ETTX Entasis Therapeutics Holdings Inc

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35 Gatehouse Drive

Waltham, MA 02451

(781) 810-0120

(Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices)

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.   Yes  ☐    No  ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Act.   Yes  ☐    No  ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to the filing requirements for the past 90 days.   Yes  ☒    No  ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).   Yes  ☒    No  ☐

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Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act  ☒

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act.)    Yes  ☐    No  ☒

As of June 30, 2021, the last business day of the registrant’s most recently completed second fiscal quarter, the aggregate market value of shares of the registrant’s common stock held by non-affiliates of the registrant was approximately $28.6 million, based on the closing price of the registrant’s common stock on The Nasdaq Global Market on June 30, 2021 of $2.67 per share. The calculation excludes shares of the registrant’s common stock held by current executive officers, directors and stockholders that the registrant has concluded are affiliates of the registrant. The determination of affiliate status is not a determination for other purposes.

As of February 25, 2022, there were 47,851,779 shares of common stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Specified portions of the registrant’s definitive proxy statement for its 2021 Annual Meeting of Stockholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2020, are incorporated by reference into Part III of this Annual Report on Form 10-K.

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Special Note Regarding Forward-Looking Statements

This Annual Report on Form 10-K contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or Exchange Act, and the Private Securities Litigation Reform Act of 1995. All statements other than statements of historical fact are “forward-looking statements” for purposes of this Annual Report on Form 10-K for the fiscal year ended December 31, 2021, or Annual Report on Form 10-K. In some cases, you can identify forward-looking statements by terminology such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expects,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” or the negative or plural of those terms, and similar expressions. These statements relate to our future plans, objectives, expectations, intentions and financial performance and the assumptions that underlie these statements. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those anticipated in the forward-looking statements. You should read these statements carefully because they discuss future expectations, contain projections of future results of operations or financial condition, or state other “forward-looking” information. Forward-looking statements include, but are not limited to, statements about:

Factors that may cause actual results to differ materially from current expectations include, among other things, those set forth in Part I, Item 1A, “Risk Factors,” herein and for the reasons described elsewhere in this Annual Report

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on Form 10-K. These statements involve substantial known and unknown risks, uncertainties and other factors that may cause our actual results, level of activity, performance or achievements to differ materially from those currently anticipated. Forward-looking statements are neither historical facts nor assurances of future performance.

This Annual Report also contains estimates, projections and other information concerning our industry, our business, and the markets for certain diseases, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Unless otherwise expressly stated, we obtained this industry, business, market and other data from reports, research surveys, studies and similar data prepared by market research firms and other third parties, industry, medical and general publications, government data and similar sources that we cannot independently verify, but believe to be reliable.

In this Annual Report on Form 10-K, unless otherwise stated or as the context otherwise requires, references to “Entasis,” “the Company,” “we,” “us,” “our” and similar references refer to Entasis Therapeutics Holdings Inc. and its wholly owned subsidiaries. The trademarks, trade names and service marks appearing in this Annual Report on Form 10-K are the property of their respective owners.

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Our third product candidate is ETX0282CPDP which is a combination of a novel, oral BLI, ETX0282, with cefpodoxime proxetil or CPDP, which has the potential to address complicated urinary tract infections, or cUTIs, including those caused by multidrug-resistant Enterobacteriaceae. We believe there is a significant unmet need for new oral antibiotics to reliably treat the estimated 3 to 4 million patients diagnosed annually with cUTIs. We have reported preliminary Phase 1 trial results, and we are now seeking a partner to help further advance ETX0282CPDP through additional clinical trials. This program was previously supported by the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator program, or CARB-X.

We are also advancing the development of a novel class of antibiotics, non β-lactam inhibitors of penicillin-binding proteins, or NBPs. We believe NBPs constitute a potential new class of Gram-negative antibacterial agents that are designed to target a broad spectrum of multidrug resistant bacterial pathogens that overcome the main source of β-lactam resistance which is driven by β-lactamase activity. This novel class of agents is designed to potentially target a broad spectrum of multidrug resistant bacterial pathogens that are part of the CDC/World Health Organization, or WHO, list of high unmet medical need or ESKAPE pathogens. We selected ETX0462 as the initial clinical candidate for this program and with support from CARB-X we are currently working to complete additional pre-clinical activities to enable the program to advance into a Phase 1 clinical trial. In June 2020, we were awarded a contract from the National Institutes of Health, or NIH, to support research towards developing additional NBP molecules with expanded Gram-negative spectrum from this novel class. This research program, designated NBP2, is attempting to target Klebsiella, Pseudomonas and E. coli from the ESKAPE list of pathogens. In July 2021, we successfully completed the first milestones for the program and were awarded the Option 1 Period of the program to proceed with further optimization, beginning August 1, 2021. Subject to achieving pre-defined milestones, the contract is expected to sufficiently fund activities to achieve submission of an investigational new drug, or IND, application to the FDA.

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Our Strategy

Our goal is to maximize the value of our targeted antibacterial agents for the treatment of serious infections caused by multidrug-resistant pathogens. Our strategy includes the following key components:

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Product Portfolio

The following table summarizes the status of our product candidates and preclinical programs:

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Antibiotics Background

The introduction of antibiotics for the treatment of bacterial infections is recognized as one of the most transformative events in medicine. Antibiotics either kill bacteria (cytocidal) or inhibit bacterial cell growth (cytostatic), in both cases allowing the body’s natural immune system to clear the bacteria. After penicillin, a β-lactam class antibiotic, entered the market in the early 1940s, antibiotics became one of the most commonly prescribed drugs in history. The modern era of antibiotics began in the 1950s with the discovery and commercialization of a number of antibiotic classes and molecules including additional β-lactams, tetracyclines, fluoroquinolones, aminoglycosides and polymyxins.

There are two main varieties of bacteria, Gram-positive and Gram-negative, which are identified using a common laboratory staining test known as the “Gram stain.” Gram-positive bacteria are surrounded by a single membrane, while Gram-negative bacteria have both an inner membrane and an outer membrane. Due to this increased complexity, it has historically been more challenging to develop products that target Gram-negative bacteria, such as Pseudomonas, Acinetobacter and Enterobacteriaceae, a family of related organisms that includes the Enterobacter species, E. coli, and Klebsiella pneumonia. In the United States, approximately 8.2 million bacterial infections are treated in the hospital annually. Approximately 60% of hospital-treated infections are Gram-negative, and over 140,000 patients treated in the hospital for Gram-negative infections die annually in the United States.

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One of the most widely used antibiotic classes are β-lactams due to the combination of their attractive safety and efficacy profile. β-lactams work by inhibiting penicillin binding proteins, or PBPs, proteins that play an important role in bacterial cell wall synthesis and are essential for the growth and reproduction of bacteria. β-Lactam antibiotics consist of all antibiotic agents that contain a β-lactam ring in their molecular structures. Among β-lactam antibiotics, penicillin derivatives and cephalosporins are the most commonly used. Carbapenems, another class of β-lactam antibiotics, are generally more effective against Gram-negative multidrug resistant pathogens; but to preserve their activity, they are often limited for use as a last resort.

Antibiotic Resistance

Antibiotic resistance is a direct consequence of antibiotic use. No sooner was penicillin adopted in clinical use, that the first cases of penicillin-resistant infections were reported. Indeed, resistance to penicillin, as was subsequently found to be the case for other natural product-derived antibiotics, pre-dates its medicinal use. This issue has escalated in the modern era, as millions of metric tons of antibiotics have been produced for human therapeutic use and use in agriculture and animal husbandry. This increased demand and use of antibiotics has contributed significantly to the emergence of resistant strains. For a period, the discovery of new antibiotics kept pace with the emergence of resistance; however, this is no longer the case and as a result, clinicians now commonly resort to using a combination of suboptimal antibiotics in an attempt to treat antibiotic resistant infections. For example, in the United States and European Union from 2004 to 2015, the use of last-resort antibiotics, carbapenems and polymyxins, increased annually by 6% and 8%, respectively. The negative consequences of this approach are twofold, as inappropriate antibiotic therapy leads to poorer outcomes for patients and potential subinhibitory and subtherapeutic antibiotic concentrations can further promote the development of antibiotic resistance.

Antibiotic resistance is now a global health threat and when bacteria develop resistance to drugs in at least three or more antibiotic classes, they are commonly referred to as multidrug-resistant. Bacteria use a number of mechanisms to develop resistance to antibiotics. Resistance to β-lactam antibiotics primarily occurs when bacteria acquire foreign genes that encode β-lactamases, enzymes that inactivate the β-lactam antibiotic by breaking apart the β-lactam ring, which renders the antibiotic inactive. Below, a β-lactamase enzyme (blue box) is shown binding to and cleaving the blue β-lactam ring of a carbapenem antibiotic. β-lactamases are widely prevalent and are classified into four classes, Classes A, B, C and D. Since 1976, researchers have discovered and developed β-lactamase inhibitors (BLIs) that essentially restore the efficacy of the β-lactam antibiotic by neutralizing β-lactamase enzymes. Despite the discovery and regulatory approval of novel BLIs, currently marketed BLIs do not broadly inhibit Class D β-lactamases, which are a particular concern in infections caused by multidrug-resistant Acinetobacter.

Antibiotic-resistant infections often result in high morbidity and, in many cases, mortality. According to the article “Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis” published in The Lancet on February 12, 2022, antimicrobial resistance was associated with approximately 4.95 million deaths and directly attributed to 1.27 million deaths in 2019. In the United States alone, antibiotic-resistant infections are estimated to add $20 billion per year to healthcare costs. Due to the limitations of current treatment options and growing antibiotic resistance rates, the pathogens targeted by our current product candidates, Acinetobacter, Pseudomonas, CRE and N. gonorrhoeae, are all identified as high priority targets by the CDC and WHO, and the Infectious Diseases Society of America, or IDSA.

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Rising antibiotic resistance has catalyzed a global call to action. Funding from government and nonprofit agencies for antibiotic research and development and an improved regulatory environment support the efficient development of novel antibiotics targeted at unmet need areas. GARDP, NIAID, the Biomedical Advanced Research and Development Authority, or BARDA, the Defense Advanced Research Projects Agency, or DARPA, the DOD, and the Innovative Medicines Initiative, all offer funding or services to support research and development of novel antibiotics.

Changes in the legal/policy landscape in the United States have also highlighted the growing importance of addressing antimicrobial resistance. Proposed legislation includes the Developing an Innovative Strategy for Antimicrobial Resistant Microorganisms Act, or DISARM, which calls for payment of qualified infectious disease products, or QIDPs, outside of the hospital diagnosis-related group, or DRG, resulting in potentially higher Medicare reimbursement for those novel antibiotics designated as QIDPs. Qualifying hospitals would be required to participate in a specified antibiotic stewardship program in order to be eligible for higher payment. More recently, this legislation was reintroduced in the U.S. House of Representatives in June 2021, which aims to amend title XVIII of the Social Security Act to encourage the development and use of DISARM antimicrobial drugs, and for other purposes. The Pioneering Antimicrobial Subscriptions to End Upsurging Resistance Act of 2020, or PASTEUR Act, was introduced to provide a mechanism for funding designated “critical need antimicrobial” drugs following FDA approval. In return, patients covered by federal insurance programs will receive these drugs at no cost. These contracts could range from $750 million to $3 billion in value. In October 2021, the Presidential Advisory Council on Combating Antibiotic-Resistant Bacteria, or PACCARB, authored a letter to the Honorable Xavier Becerra Secretary, Department of Health and Human Services recommending the passage of both DISARM and PASTEUR and the antimicrobial stewardship provisions contained within each act.

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Our Product Candidates

Sulbactam-durlobactam (SUL-DUR)

Overview

Our lead product candidate, SUL-DUR, is a novel IV antibiotic with broad spectrum β-lactamase coverage including Classes A, C and D. The product is a combination of sulbactam, a β-lactam antibiotic, and durlobactam, our novel BLI, that we are developing for the treatment of a variety of serious infections caused by carbapenem-resistant Acinetobacter. We have completed three separate Phase 1 clinical trials, including one evaluating the penetration of SUL-DUR into the lung and one in renally impaired patients. Subsequently, we completed a Phase 2 clinical trial in patients with cUTIs. We initiated ATTACK, our single Phase 3 registration trial in 2019, that evaluated SUL-DUR in patients with confirmed carbapenem-resistant Acinetobacter pneumonia and/or bloodstream infections. We announced positive top-line Phase 3 data in October 2021 and based on our positive top-line Phase 3 data and the totality of our preclinical and clinical data, announced our intention to file an NDA with the FDA in mid-2022. We believe SUL-DUR has the ability to improve outcomes of patients with multidrug-resistant Acinetobacter infections, reducing their overall mortality.

Acinetobacter

Acinetobacter is a Gram-negative, opportunistic human pathogen that predominantly infects critically ill patients often resulting in severe pneumonia and bloodstream infections but can also infect other body sites as well. Once thought to be mostly benign, Acinetobacter is now considered a global threat in the healthcare setting due in part to its ability to acquire multidrug resistance at rates not previously seen in other bacteria. In addition, Acinetobacter has the ability to remain viable for up to 100 days in dry conditions and easily spreads via air or water droplets, which explains why the pathogen can often be found in many locations in the intensive care unit, or ICU, including bedrails, bedside tables, monitors of mechanical ventilators, intravenous pumps, door handles, stethoscopes and many other locations. Of significant concern, one study reported greater than 98% of Acinetobacter isolates in an ICU from non-clinical sources such as bedrails and door handles, were determined to be multidrug resistant.

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Pneumonia and bloodstream infections caused by drug-resistant Acinetobacter can have mortality rates approaching 50%. Antibiotic-resistance rates of Acinetobacter to current standard-of-care treatments are some of the highest reported, between 30% and 50% in the United States and greater than 90% in parts of Europe and Asia. Acinetobacter resistance to β-lactams is primarily driven by the expression of Class D β-lactamases, often in combination with Class A and/or Class C β-lactamases. There are currently no effective antibiotics indicated for the treatment of multidrug-resistant Acinetobacter infections. Durlobactam is the first clinical-stage BLI with sufficient broad-spectrum activity against class A, C, and D β-lactamases to potentially restore the efficacy of β-lactam antibiotics against multidrug-resistant Acinetobacter.

Sulbactam, the β-lactam antibiotic used in SUL-DUR has superior microbiological potency against Acinetobacter compared to other β-lactam antibiotics based on in vitro and in vivo analyses. Historically, physicians used sulbactam to successfully treat Acinetobacter infections before development of broad β-lactamase mediated resistance rendered sulbactam on its own largely ineffective. We believe our data demonstrates that combining durlobactam with sulbactam can effectively restore the activity of sulbactam against multidrug-resistant strains of Acinetobacter.

Market Opportunity

We estimate that there are 180,000 to 220,000 hospital-treated Acinetobacter infections annually in the United States and Europe, of which 65,000 to 100,000 are carbapenem-resistant Acinetobacter infections, which we regard as our initial target markets for SUL-DUR. We also believe there could be a significant market opportunity in Asia-Pacific, Central and South America, Russia and the Middle East given resistance rates exceeding 80% in some countries. If approved, we believe SUL-DUR has the potential to address the issues of resistance facing existing regimens, which is currently limiting the utility of the carbapenems, and tolerability, which is a concern with regimens containing colistin. There are currently no antibiotics indicated for the treatment of carbapenem-resistant Acinetobacter infections.

Clinical Development Plan

Completed Clinical Trials

Phase 3 registration trial: We completed ATTACK, a Phase 3 registration trial of SUL-DUR for the treatment of patients with carbapenem-resistant Acinetobacter infections, with positive top-line data announced in October 2021. ATTACK enrolled 207 patients at 95 clinical sites in 16 countries. This was a two-part trial with Part A being the randomized, comparative portion (SUL-DUR vs colistin) in patients with documented Acinetobacter hospital-acquired bacterial pneumonia (HABP), ventilator-associated bacterial pneumonia (VAPB), ventilated pneumonia (VP), or bacteremia, and Part B being an open-labeled portion including Acinetobacter infections resistant to, or having previously failed colistin or polymyxin B treatment. Baseline Acinetobacter isolates tested were greater than 95% carbapenem resistant.

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SUL-DUR met the primary efficacy endpoint of 28-day all-cause mortality compared to colistin in the CRABC m-MITT population of Part A. SUL-DUR mortality was 19.0% (12/63) compared to 32.3% (20/62) in the colistin arm (treatment difference of -13.2%; 95% CI: -30.0, 3.5). Similar trends were demonstrated in 28-day and 14-day all-cause mortality favoring SUL-DUR across all study populations evaluated to date. A statistically significant difference in clinical cure at Test of Cure (TOC) was observed with 61.9% in SUL-DUR arm compared to 40.3% in the colistin arm (95% CI 2.9-40.3). In Part B, the 28-day all-cause mortality was 17.9% (5/28) and consistent with that observed in Part A.

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Safety analyses from a total of 177 patients suggested that SUL-DUR was generally well-tolerated with a favorable safety profile compared to colistin. SUL-DUR met the primary safety objective with a statistically significant reduction in nephrotoxicity as measured by the RIFLE classification for acute kidney injury. SUL-DUR nephrotoxicity was 13.2% (12/91) versus 37.6% (32/85) in the colistin arm (p = 0. 0002). Overall adverse events (AEs) in the safety population were comparable between treatment groups with 87.9% (80/91) in the SUL-DUR arm vs. 94.2% (81/86) in the colistin arm in Part A, 89.3% (25/28) in Part B. Drug related AEs were 12.1% (10.7% in Part B) with SUL-DUR compared to 30.2% with colistin. The most common non-infectious AEs (≥10%) in the SUL-DUR arm were diarrhea (16.5%), allergic and hypersensitivity reactions (16.5%), anemia (13.2%) and hypokalemia (12.1%) in Part A. These AEs were also >10% in the colistin arm as was acute kidney injury.

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We believe that the data from the ATTACK trial, data from our other clinical trials of SUL-DUR and non-clinical data will be sufficient to submit an NDA to the FDA in mid-2022.

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Phase 2 clinical trial in cUTI patients: We completed a Phase 2 clinical trial in cUTI patients to provide additional safety and pharmacokinetic, or PK, data as well as efficacy data against carbapenem-resistant pathogens. Eighty patients were randomized to receive either a dose of SUL-DUR or placebo every six hours for seven days. Patients in both arms also received background therapy, which is current standard-of-care, with 500 mg of imipenem, or IMI, administered through IV every six hours. There were no serious adverse events reported and the adverse event profile of SUL-DUR plus IMI was similar to that of the IMI comparator arm. PK data observed in the Phase 2 trial was consistent with the PK data observed in the Phase 1 clinical trial in healthy volunteers.

We have completed three Phase 1 clinical trials, highlighted below, in addition to a Phase 2 clinical trial in patients with cUTIs. In all of these clinical trials, SUL-DUR was observed to be generally well tolerated.

Four-part Phase 1 first-in-human trial: Our four-part Phase 1 first-in-human clinical trial was conducted in Australia in 124 healthy volunteers. SUL-DUR was generally well tolerated, with no dose-related systemic adverse events or drug-related serious adverse events reported. SUL-DUR also exhibited linear dose-dependent increases in exposure and PK parameters across the dose range studied.

Phase 1 lung trial: Our Phase 1 lung trial assessed the concentration of SUL-DUR in lung fluid, an important metric to understand, because ATTACK includes patients with pneumonia and lack of appropriate lung tissue penetration has been found to contribute to reduced efficacy. We believe that the levels of SUL-DUR in the lung fluid achieved in this trial support its continued development as a potential treatment for pneumonia caused by Acinetobacter.

Phase 1 renal trial: Our Phase 1 renal trial analyzed serum levels in renally impaired patients and provided data to enable the development of a dose adjustment protocol for the type of patient targeted in our ongoing Phase 3 registration trial.

We submitted an IND for SUL-DUR to the FDA in June 2017, and the FDA notified us in July 2017 that we could proceed with this program. The FDA granted Fast Track and QIDP designation for SUL-DUR in September 2017 for the treatment of hospital-acquired and ventilator-acquired bacterial pneumonia and bloodstream infections due to Acinetobacter. 

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Global Acinetobacter Surveillance Data

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We designed durlobactam to achieve broad activity against a wide range of β-lactamases, including Classes A, C and D, unlike currently marketed BLIs that primarily cover only Class A and Class C β-lactamases. Durlobactam is the first BLI in clinical development with such a broad spectrum of in vitro activity.

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SUL-DUR has also exhibited potent microbiological activity against Acinetobacter strains in vitro. Over a series of studies summarized in the figure below, we have compared the effectiveness of SUL-DUR, sulbactam alone and comparators in inhibiting 7,221 strains of Acinetobacter that were collected from patients around the world between 2011 and 2020. Amikacin and colistin were tested against 6,418 of the 7,221 strains. The plot in the figure below

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presents the cumulative percentage of these strains inhibited by increasing concentrations of each of the tested compounds. Sulbactam alone, as well as most of the other marketed antibiotics, had a very high MIC₉₀ value of 64 mg/L, meaning that concentrations of 64 mg/L or greater were required to inhibit growth of 90% of the strains. The corresponding breakpoints, which are established by the Clinical & Lab Standards Institute, or CLSI, as the specified concentrations for each antibiotic that define whether a strain is considered resistant, are significantly lower than their MIC₉₀ values. If the MIC₉₀ of a drug is lower than its CLSI breakpoint, then that drug would be expected to be effective against more than 90% of the strains. If a drug’s MIC₉₀ is higher than its breakpoint, the drug would not be expected to have broad efficacy against those strains. This cumulative analysis suggests that recent global strains of Acinetobacter are resistant to all the comparator antibiotics other than colistin, consistent with their significantly diminished clinical utility against Acinetobacter infections. In contrast, SUL-DUR had very potent activity, with a much lower MIC₉₀ of 2 mg/L. This is lower than the CLSI breakpoint for sulbactam, which is 4 mg/L (in Unasyn®, a combination of sulbactam and ampicillin), suggesting that our chosen target exposure levels of SUL-DUR may be effective against more than 90% of global, multidrug resistant Acinetobacter strains. A subset of 926 isolates out of the 7,221 strains tested were from Chinese hospitals collected in 2016-2018. 831 of the 926 (84.6%) Chinese isolates were carbapenem-resistant. In contrast, SUL-DUR showed potent activity against this subset, with an MIC₉₀ of 2 mg/L and 97.9% of isolates susceptible to ≤ 4 mg/L of SUL-DUR.

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Competition

We are initially developing SUL-DUR for the treatment of multidrug-resistant Acinetobacter infections. Due to rising resistance rates, standard-of-care treatment for multidrug-resistant Acinetobacter infections often includes a combination of several last-line treatment options, including carbapenems, tetracyclines, polymyxins, and other generically available agents. Despite using best available therapy, mortality rates of patients with multidrug-resistant Acinetobacter infections is reported as high as 50%. As of the date of this report, we are not aware of any marketed antibiotic that is indicated for the treatment of multidrug-resistant Acinetobacter infections; however, we are aware of other potentially competitive products that have shown in vitro activity against some strains of Acinetobacter. Melinta Therapeutics Inc. currently markets minocycline while La Jolla Pharmaceutical Company, Inc. currently markets eravacycline for complicated intra-abdominal infections. Although recently approved for treating cUTIs, Fetroja^®, from Shionogi & Co., Ltd., includes in its label a specific warning of an observed increase in all-cause mortality in patients with carbapenem-resistant Gram-negative bacterial infections that were treated with the drug. BioVersys AG reported in

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March 2021 that their lead program BV100 is progressing in Phase 1 clinical development specifically for multidrug-resistant Acinetobacter infections.

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Manufacturing Approach

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We contract with third party contract manufacturing organizations for the manufacture, packaging and labeling of sulbactam and durlobactam for preclinical studies and clinical trials, and we intend to continue to use third party manufacturing organizations in connection with any future commercialization of SUL-DUR. We continue to work with our current manufacturing partners to improve processes to increase our manufacturing capacity, reduce overall cost of manufacturing, and implement other steps toward commercial readiness. Our current manufacturing partners produce drug substance and drug product pursuant to agreements that require compliance with current Good Manufacturing Practices (cGMP). We are currently negotiating commercial supply agreements with third party manufacturing organizations and will look to finalize these agreements as part of commercial readiness.

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Commercial Approach

In the United States, our commercial strategy is driven by our understanding of where Acinetobacter infections are known to exist. Given that Acinetobacter infections more commonly occur in immunocompromised patients, treatment settings for these patients are frequently large intensive care units (ICUs), specialized centers like transplant, cancer, and burn, outpatient long-term acute centers (LTACs) and home infusion.

SUL-DUR has been developed specifically for multi-drug resistant Acinetobacter infections and we believe the unmet need and value proposition of SUL-DUR will support its use for treating infections caused by this serious Gram-negative pathogen. This value proposition includes:

Current Acinetobacter treatment protocols allow for clear positioning of SUL-DUR. Patients with suspected Acinetobacter infections are frequently treated with a broad-spectrum antibiotic, commonly a carbapenem, as first-line therapy. If susceptibility testing identifies that the causative bacterial pathogen is carbapenem-resistant Acinetobacter, the patient is then frequently switched to a colistin-based antibiotic regimen in an attempt to successfully treat the infection. Published literature, however, reports greater than 50% mortality rates using colistin-based regimens. We believe that the data from the ATTACK Phase 3 registration trial demonstrate improved efficacy and safety profiles, that could result in SUL-DUR, if approved, being preferred to a colistin-based regimen for the treatment of multidrug-resistant, including carbapenem-resistant, Acinetobacter infections.

Multidrug-resistant Acinetobacter infections also present a significant unmet medical need in China and across the broader Asia/Pacific territory. Our collaboration and license agreement with Zai Lab, which included their participation in the ATTACK Phase 3 registration clinical trial, provides a potentially accelerated path for regulatory approval and commercialization in China and Asia-Pacific territories. Zai Lab supported the enrollment of approximately 25% of the evaluable patients in ATTACK from China, which we believe will support a regulatory

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submission in China. Under our agreement with Zai Lab, we receive upfront, milestone and royalty payments in addition to payment of certain Phase 3 registration clinical trial costs. We maintain 100% of the rights and associated economics in North America and Europe. Outside of the United States, we intend to work with multi-national pharmaceutical companies to leverage their commercialization capabilities in territories not covered by our agreement with Zai Lab.

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Zoliflodacin

Overview

Our second late-stage product candidate is zoliflodacin, a potential single oral dose cure for the treatment of uncomplicated gonorrhea caused by the bacterial pathogen N. gonorrhoeae. Gonorrhea is an area of significant medical need and zoliflodacin is the only novel single dose treatment in development that provides a potential monotherapy oral alternative to intramuscular injections of ceftriaxone for the treatment of gonorrhea, including infections caused by drug-resistant strains. Zoliflodacin targets the validated mechanism of action of the fluoroquinolone class of antibiotics but does so in a novel manner to avoid existing fluoroquinolone resistance. We have completed several Phase 1 clinical trials and a Phase 2 clinical trial of zoliflodacin in patients with uncomplicated gonorrhea. In collaboration with GARDP, in 2019 we initiated a single Phase 3 registration trial of zoliflodacin in patients with uncomplicated gonorrhea. GARDP will fund all the Phase 3 clinical trial and pharmaceutical development costs and in return will receive commercial rights for zoliflodacin in WHO-defined low-income and select middle-income countries. We have retained commercial rights in all other countries, including the major markets in North America, Europe and Asia-Pacific.

Gonorrhea

Uncomplicated gonorrhea is an N. gonorrhoeae infection of the urethra, cervix, pharynx or rectum, and is more common than complicated gonorrhea, which includes spread of the infection to other tissues and potentially the bloodstream. Gonorrhea can be associated with serious complications, including pelvic inflammatory disease, ectopic pregnancy and infertility, as well as an increased risk of human immunodeficiency virus, or HIV. Despite the continued use of effective antibiotics, it remains one of the most common sexually transmitted bacterial infections in the world with an estimated 87 million people worldwide infected each year. The occasional absence of symptoms, more frequent in women, is thought to be one reason for sustained levels of infection. Reports on the lack of a robust immune response to infection by N. gonorrhoeae in humans is also thought to facilitate not only initial infection but also reinfection. Efforts to develop a prophylactic vaccine for N. gonorrhoeae continue; however, to date all have failed, again thought to be the result of insufficient or absent protective immunity to N. gonorrhoeae infections in humans. Taken together, antibiotics remain the mainstay for treating uncomplicated gonorrhea caused by N. gonorrhoeae.

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N. gonorrhoeae is the bacterial pathogen responsible for gonorrhea and has a strong propensity for uptake of chromosomal DNA from other genera of Neisseria which allows the bacteria to accumulate many mutations in chromosomal genes leading to frequent resistance of antibiotics. For example, penicillin was introduced for N. gonorrhoeae infections in 1943, and initial resistance was reported in 1945. Fluoroquinolone antibiotics were first used to treat gonorrhea in 1949 and have been one of the most successful classes of antibiotics against N. gonorrhoeae, but even so resistance was identified in 1969. One member of this class, ciprofloxacin, was introduced in 1980 and resistance was identified in 1990. More recently cephalosporin antibiotics, notably cefixime, had been widely used for the treatment of gonorrhea due to their oral administration along with a favorable efficacy and safety profile, although resistance by N. gonorrhoeae has been reported since 2007. As widespread use of these antibiotics drove the emergence of drug-resistant N. gonorrhoeae strains, treatment guidelines have subsequently been amended. Ceftriaxone is currently the only CDC-recommended option for the treatment of gonorrhea and, until recently, was administered with azithromycin, a broad-spectrum antibiotic, to provide coverage against other sexually transmitted diseases that tend to occur concurrently with gonorrhea. However, rising resistance of N. gonorrhoeae to azithromycin recently prompted the CDC to now recommend ceftriaxone monotherapy. Ceftriaxone is administered by intramuscular injection, which can be painful and may require patient monitoring by a healthcare administrator. Although ceftriaxone remains effective in most of the U.S., in Hawaii as well as in several countries, including China, Japan, Vietnam, South Korea, France and Spain, N. gonorrhoeae strains with resistance to azithromycin and ceftriaxone have been reported, prompting concerns that multidrug-resistant gonorrhea may become a major community health issue.

Market Opportunity

N. gonorrhoeae is an immediate global public health threat with 84.2 million cases worldwide in 2020 (WHO estimate). Cases of gonorrhea in the United States have reached an estimated 1.6 million per year. The WHO worldwide estimated of approximately 82.4 million new cases includes infected adolescents and adults aged 15–49 years. The CDC estimates that the cases of gonorrhea in the United States have been increasing at least 10% per year since 2009. In April 2021, the CDC announced that sexually transmitted diseases in the U.S. reached all-time high for 6th consecutive year, with approximately 2.6 million cases of chlamydia, gonorrhea & syphilis reported in 2019.

The results of a 2017-2018 survey of countries reporting decreased susceptibility, DS, or resistance, R, of N. gonorrhoeae to current antibiotics is reflected in the table below.

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Historically, to reduce the risk of spreading drug-resistant N. gonorrhoeae, the CDC has changed treatment guidelines when resistance rates to recommended first-line treatments reach 5%. Since 2015, there has only been one recommended treatment on CDC guidelines for gonorrhea: 250mg intramuscular injection of ceftriaxone plus 1g of oral azithromycin. In 2020 the CDC once again updated its treatment guideline, now recommending a 500mg intramuscular injection of ceftriaxone for treatment of uncomplicated gonorrhea. This follows a 2019 update in the United Kingdom where recommended empirical treatment of gonorrhea is now 1g intramuscular ceftriaxone monotherapy.

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Clinical Development Plan

Ongoing Registration Trial

Phase 3 registration trial: In 2019, we announced the initiation of a global, multi-center Phase 3 registration trial in collaboration with GARDP who is conducting and funding all Phase 3 clinical trial and pharmaceutical development costs. Up to 18 clinical trial sites are planned across the U.S., Thailand, South Africa, the Netherlands and Belgium. Our Phase 3 registration trial is a multi-center, open-label, noninferiority trial in approximately 1,000 enrolled patients with uncomplicated gonorrhea who will be randomized on a 2:1 basis to receive either a single 3.0g oral dose of zoliflodacin or a regimen of 500mg intramuscular ceftriaxone plus 1g oral azithromycin. The primary endpoint will be the proportion of patients with microbiological cure at urethral or cervical sites, approximately six days after treatment. The Data Safety Monitoring Board, or DSMB, in May 2021 recommended to continue the study without modification. Despite the ongoing challenges with the COVID-19 pandemic, we have observed an increase in the enrollment rate during the past two quarters and based on current enrollment rates we anticipate completion of trial enrollment in 2023. Based on our discussions with the FDA, we believe that the efficacy data from this single Phase 3 registration trial, if positive, along with the data from our other clinical trials of zoliflodacin, will be sufficient to support the submission of an NDA to the FDA.

Completed Clinical Trials

Phase 2 clinical proof-of-concept trial: We have completed a multi-center, randomized, open-label Phase 2 clinical trial comparing a single oral dose of 2.0g or 3.0g of zoliflodacin to 500mg intramuscular ceftriaxone for the treatment of uncomplicated gonorrhea. In this trial, 179 randomized patients received treatment and zoliflodacin was generally well tolerated, with efficacy outcomes comparable to ceftriaxone. Microbiological eradication and clinical cure in urogenital infections with a single dose of zoliflodacin, the primary endpoint of the trial, was comparable to ceftriaxone, with 100% cure rate in both the 3.0g zoliflodacin and ceftriaxone groups in the per-protocol population. The results of this clinical trial were published in The New England Journal of Medicine in 2018.

Phase 1 clinical trial: We evaluated zoliflodacin in two Phase 1 clinical trials studying 72 healthy volunteers in total. In one trial, we evaluated PKs and tolerability in 48 subjects and food effects in 18 subjects, and in the second trial, we evaluated absorption, distribution, metabolism and excretion in six subjects. Zoliflodacin was generally well tolerated in these trials at doses we would expect to be clinically active for treating uncomplicated gonorrhea. Administration of a high-fat meal was associated with an increase in zoliflodacin plasma concentration, suggesting that zoliflodacin could be administered with or without food.

Preclinical Data

We have generated biochemical, microbiological and in vivo data on zoliflodacin. The data suggest that zoliflodacin retains potent activity against contemporary clinical isolates in the U.S., Europe, China, Thailand and South Africa that are resistant to other antibiotic classes including fluroquinolones, which was expected given its novel mechanism of action. In addition, the data show significant resistance against two of the four standard antibiotics indicated for gonorrhea, ciprofloxacin, a fluoroquinolone, and azithromycin, a macrolide.

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Competition

We are initially developing zoliflodacin as a single oral dose treatment for uncomplicated gonorrhea. Gonorrhea is commonly treated with combination therapy intramuscular ceftriaxone injection and oral azithromycin, both generically available agents. Additional generic cephalosporins and fluoroquinolones are also prescribed, but not recommended as primary treatment options given current resistance rates. Gepotidacin, currently under development for a variety of infections by GlaxoSmithKline plc, is the only potentially competitive product candidate in late-stage clinical development that we are aware of that is being developed for the treatment of uncomplicated urogenital gonorrhea. A Phase 3 clinical trial (EAGLE-1) was initiated by GlaxoSmithKline in October 2019. A prior Phase 2 clinical trial revealed the emergence of resistance to gepotidacin in 2 urogenital microbiological failures following administration of a single oral dose. In an attempt to overcome this resistance, gepotidacin will be given in two oral doses in the EAGLE-1 clinical trial; a 4-tablet 3000 milligram (mg) oral dose at the study site followed by another 4-tablet 3000mg oral dose as an outpatient.

Manufacturing Approach

GARDP has partnered with third party contract manufacturing organizations for the manufacture of drug substance and drug product for zoliflodacin. These partners are capable of producing commercial scale quantities of zoliflodacin drug substance and drug product under cGMP conditions. GARDP will develop direct long-term commercial supply agreements for sales in their respective territories. As we execute upon our commercialization strategy for zoliflodacin, we intend to work with the established zoliflodacin manufacturing partners for our commercial supply.

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Commercial Approach

Antibiotics to treat uncomplicated gonorrhea will typically be available through primary care physicians, outpatient clinics and emergency rooms, and numerous community sites. In addition, placement on CDC guidelines has historically driven awareness and uptake in the U.S. We have partnered with GARDP who will lead the commercialization of zoliflodacin in certain WHO-defined low-income and specified middle-income countries.

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Zoliflodacin is a potential single dose cure (sachet in water) that can facilitate “expedited partner therapy” at home, which may lower the chance for a repeat infection from a partner. Expedited partner therapy, or EPT, is the clinical practice of treating the sex partners of patients diagnosed with chlamydia or gonorrhea by providing prescriptions or medications to the patient to take to his/her partner without the health care provider first examining the partner. Within the United States, EPT is permissible in 45 states, potentially allowable in 4 states and is only prohibited in one state.

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ETX0282CPDP

Overview

Our third product candidate is ETX0282CPDP for the potential oral treatment of cUTIs in the outpatient setting. ETX0282CPDP is a combination of ETX0282, a novel oral BLI, with cefpodoxime proxetil, or cefpodoxime, an oral β-lactam antibiotic. We believe ETX0282 is a highly differentiated oral β-lactamase inhibitor based on its broad inhibition of both Class A and Class C β-lactamases. We selected cefpodoxime as the β-lactam antibiotic to combine with ETX0282 following in vitro studies in which cefpodoxime exhibited superior activity against multidrug-resistant Enterobacteriaceae compared to other existing oral β-lactams. Cefpodoxime was once used to treat cUTIs, among other indications, but its clinical utility is currently limited by β-lactamase-mediated resistance. We believe ETX0282 has the potential to restore the efficacy of cefpodoxime against multidrug-resistant Enterobacteriaceae. We have reported initial Phase 1 results, which indicate ETX0282 is generally safe and well tolerated and supports further progression. Having successfully completed the initial Phase 1 studies and preclinical work to deliver a formulation with the desired extended release profile, we now are seeking a partner to help further advance ETX0282CPDP through additional clinical trials.

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Urinary Tract Infections

A urinary tract infection, or UTI, diagnosis can be classified as either uncomplicated or complicated. Uncomplicated UTI is an infection of one or more parts of the urinary tract system such as the kidneys, ureters, bladder or urethra with symptoms confined to the lower urinary tract and is often treated with generic oral antibiotics in the community setting. Uncomplicated UTIs, if left unresolved, can have serious consequences, including life-threatening kidney infections. cUTIs, including pyelonephritis, occur in a urinary tract that has metabolic, functional, or structural abnormality and include patients with comorbidities or patients with bladder catheters. These factors contribute to decreased resolution of such infections and therefore frequently require hospital-based therapy. ETX0282CPDP is designed to treat cUTIs, including those caused by multi-drug resistant Enterobacteriaceae, including some carbapenem-resistant strains, or CRE. Enterobacteriaceae species cause approximately 85% of all UTIs, of which E. coli is the most common pathogen, causing approximately 75% of infections. In addition, Klebsiella and Pseudomonas are also relatively common UTI pathogens. The emergence of multidrug-resistant bacteria has reduced the efficacy of commonly used oral antibiotics such as levofloxacin and ciprofloxacin, both fluoroquinolones, and trimethoprim/sulfamethoxazole. In the United States, over 30% of UTIs caused by E. coli and 10% of UTIs caused by Klebsiella are resistant to fluoroquinolones.

Market Opportunity

Patients with UTIs caused by bacteria resistant to existing oral treatment options frequently require hospital admission for treatment with IV antibiotics, even when they are otherwise healthy and fit to be treated outside the hospital setting. In the United States, it is currently estimated that between 3 and 4 million UTIs are treated in the hospital per year. Hospital admission not only leads to inconvenience for the patient and high treatment cost for the healthcare system, but it also increases the risk of transmitting drug-resistant bacterial strains to other hospitalized patients and potentially exposing UTI patients to other, more serious hospital-acquired infections. There are currently no effective oral treatments available for cUTIs, including those caused by multi-drug resistant Enterobacteriaceae. If approved, we believe ETX0282CPDP will provide clinicians a convenient, oral option to treat patients suffering from cUTIs caused by these multidrug-resistant pathogens, which could reduce the need for hospital or outpatient IV treatment of these infections. There is also an opportunity for ETX0282CPDP to facilitate early hospital discharge following a short course of IV antibiotics.

Clinical Development Plan

Phase 1 clinical trial: We conducted a multi-part Phase 1 clinical trial of ETX0282 in Australia and initial data readout in June 2019. The Phase 1 clinical trial was a randomized, double-blind and placebo-controlled study of ETX0282 alone, not in conjunction with CPDP and was designed to investigate safety, pharmacokinetics, drug-drug interactions and food effect in 99 healthy volunteers enrolled in 12 cohorts. The completed cohorts were; Part A: single-ascending dose escalation, fasted; Part B: food effect: fasted versus high fat meal; Part C: multiple dose with regular meals; Part D: drug-drug interaction with regular meals; and Part G: simulation of a high-fat PK profile (fasted).

Overall, the key findings were that ETX0282 was found to be generally safe and well tolerated, no significant adverse events were reported. ETX0282, as the prodrug, was rapidly converted to ETX1317, the active form of the drug, at all doses. Plasma concentrations were in therapeutic range and the conversion of ETX0282 to ETX1317 was not impacted by multiple dosing and with minimal accumulation. No drug-drug interactions were observed with cefpodoxime. 11 out of 77 subjects receiving ETX0282 experienced mild to moderate emesis (vomiting). The trial data indicated that emesis may be ameliorated by dosing with a high fat meal (not a normal diet). When ETX0282 was dosed in fasted healthy volunteers in a manner to mimic the PK of the high fat meal plus ETX0282 (Part G), no emesis was observed. Having reported preliminary Phase 1 trial results, we are now seeking a partner to help further advance ETX0282CPDP through additional clinical trials.

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Competition

We initially designed ETX0282CPDP for the potential oral treatment of cUTIs in the outpatient setting. There are a variety of generically available antibiotic classes with limited utility available for the treatment of such infections, including cephalosporins, carbapenems and fluoroquinolones. Additionally, there are several approved IV branded agents targeting multidrug-resistant cUTIs, including Avycaz^®, Vabomere^®, Zemdri^®, as well as the more recently approved IV products Fetroja^® (Shionogi & Co., Ltd) and Recarbrio^® (Merck & Co., Inc.). We are aware of additional potentially competitive oral product candidates that may address a limited breadth of multidrug-resistant Gram-negative pathogens including tebipenem from Spero Therapeutics Inc., which completed a Phase 3 clinical trial and filed an NDA submission to the FDA in the fourth quarter of 2021. Sulopenem, from Iterum Therapeutics Limited, has completed Phase 3 clinical trials and in the third quarter of 2021 received a Complete Response Letter, or CRL, from the FDA requesting additional data to support approval of oral sulopenem for the treatment of adult women with uncomplicated UTIs. Additional potentially competing programs in clinical development are Venatorx Pharmaceuticals’ Phase 1 VRX-7145, an orally bioavailable beta-lactamase inhibitor (BLI) in a fixed combination with the third generation orally bioavailable cephalosporin, ceftibuten. Initial Phase 1 data on VRX-7145 was announced in July 2021. Qpex Biopharma Inc. has announced the initiation of Phase 1 studies of ORAvance™, an ultra-broad-spectrum oral beta-lactamase inhibitor for use in combination with beta-lactam antibiotics for drug-resistant gram-negative bacterial infections.

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ETX0462

Overview

Leveraging our targeted-design platform, we have developed a potential new class of novel antibiotics that are non-β-lactam penicillin binding protein inhibitors which we are referring to as NBPs. In late 2019, we selected a new drug candidate from our NBP platform, ETX0462, a novel unsaturated diazabicyclooctane with antimicrobial activity against multiple Gram-negative pathogens including Pseudomonas aeruginosa, as well as a number of high-priority biothreat pathogens. If successful in development, we believe our NBPs would be the first, novel Gram-negative antibiotic class since the carbapenems were introduced in 1985. In collaboration with CARB-X, we are advancing this program through registration safety studies and pre-formulation development and there is an option for support into Phase 1 human studies upon successful completion of the ongoing studies.

Pseudomonas

Infections caused by multidrug-resistant Pseudomonas are some of the most difficult to treat bacterial infections today. Carbapenems and cephalosporins are commonly used to treat susceptible cases of Pseudomonas. However, in the United States, approximately 20% of Pseudomonas are resistant to both classes of antibiotics. Some recently approved antibiotics demonstrate improved efficacy against Pseudomonas but are still prone to multiple mechanisms of resistance. In many cases, the only treatment option for multidrug-resistant Pseudomonas is colistin or other antibiotics of the same class. While these antibiotics are potent in preclinical models, in practice, clinicians tend to reserve their use as last resort treatment options due to their toxicity in the kidney and nervous system, which limits dosing and, therefore, clinical efficacy.

Market Opportunity

Pseudomonas causes a variety of opportunistic infections, including intra-abdominal infections, surgical site infections, UTIs and nosocomial pneumonia. Pseudomonas is the most common Gram-negative pathogen associated with ventilator-acquired pneumonia. This is due in-part to the larger genome compared to other bacteria, which enables Pseudomonas to encode enzymes that metabolize, transport and efflux antibiotics. In addition, biofilm formation has been reported in the lungs of patients infected with Pseudomonas, which acts as a barrier preventing antibiotic access to the bacteria. Pseudomonas infections are on the rise with an estimated 600,000 to 750,000 cases occurring annually in the United States. In 2014, approximately 20% of Pseudomonas infections were resistant to each of carbapenems, cephalosporins and fluoroquinolones and 14% were resistant to at least three classes of antibiotics. We believe our novel class of NBPs, including ETX0462, has the potential to be used as monotherapy against infections caused by multidrug-resistant Pseudomonas.

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Competition

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We are initially developing ETX0462 for the treatment of infections caused by multidrug-resistant Pseudomonas. There are a variety of generically available antibiotic classes available for the treatment of antibiotic sensitive Pseudomonas infections, including cephalosporins, carbapenems and fluoroquinolones. However, there are fewer options for multidrug resistant Pseudomonas. Generic polymyxins like Colistin are often utilized in these infections, as are branded IV antibiotics including Avycaz® (Allergan Inc.), Zerbaxa®, and Recarbrio® (both from Merck & Co., Inc.) and Vabomere^® (Melinta, Inc.). Cayston® (Gilead Inc.) is an inhaled antibiotic addressing Pseudomonas infections in the lungs of cystic fibrosis patients. Zerbaxa® and Cayston® are unfortunately not active when Pseudomonas expresses a carbapenemase enzyme but can potentially overcome other forms of resistance. The other three branded agents are BL/BLI combinations, and Pseudomonas has begun to develop resistance to this class of antibiotics via porin channel mutations or efflux pumps. We are aware of additional potentially competitive product candidates in clinical development that may address certain Pseudomonas infections including: Ftortiazinon, a small molecule in Phase 2 from the Gamaleya Research Institute (Russia); AR101, a monoclonal antibody in Phase 2 from Aridis Pharmaceuticals Inc.; AP-PA02, a Phase 1b/2 phage candidate from Armata Pharmaceuticals Inc.

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Supply and Manufacturing

We do not own or operate manufacturing facilities to produce any of our product candidates, nor do we have plans to develop our own manufacturing operations in the foreseeable future. We currently rely on third-party contract manufacturers for our required raw materials, drug substance, and finished drug product for our preclinical research and clinical trials. Although we have contracts with these third parties to meet our current clinical supply needs, we do not have any current contractual relationships with these third parties for the manufacture of commercial supply of our product candidates after they are approved. As our product candidates approach potential approval by any regulatory agency, we intend to enter into agreements with third-party contract manufacturers for the commercial production of those products. We currently employ internal resources to manage our manufacturing vendor relationships and processes.

Government and Nonprofit Awards

Through December 31, 2021, we have received aggregate financial commitments of up to $24.4 million from the Trustees of Boston University through the CARB-X program, the U.S. Army Medical Research Acquisition Activity, a division of the U.S. Department of Defense, and NIAID in support of our ETX0282, ETX0462, NBP and discovery research programs. The CARB-X awards could provide up to a total of $18.5 million in funding and the NIH award could provide up to a total $15.5 million in funding based on the successful completion of prespecified milestones. These specified milestones include the completion of important steps for a development-stage project such as preclinical studies or clinical trials, manufacture and formulation work, submission of regulatory applications and regulatory meetings with the FDA or comparable foreign regulator.

COVID-19 Business Impact

The COVID-19 pandemic continues to impact the global economy and healthcare industry, causing disruptions to business operations, interruptions in supply chains, and crowding hospitals and other healthcare facilities. With regard to our operations ,the pandemic continues to impact our ongoing clinical trial for zoliflodacin as patients either avoid seeking treatment or fail to return for follow-up visits due to crowded healthcare facilities. Aside from this impact, the pandemic has had little to no impact on our employees, other research and development pipeline programs, our ability to communicate with and manage our key vendors, partners, and drug supply chains, and accurately and timely file our financial statements. Although we are continuing to actively monitor and assess the effects of the COVID-19 pandemic on our business and pipeline programs, the ultimate impact of the COVID-19 pandemic is highly uncertain and subject to change.

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License and Collaboration Agreements

A significant part of our strategy is to partner with established pharmaceutical companies, as well as nonprofit organizations, government agencies and other third parties to provide financial and technical support in the development and marketing of our products.

Zai Lab

In April 2018, we entered into a license and collaboration agreement with Zai Lab for the development and commercialization of products containing durlobactam or SUL-DUR in the following countries in the Asia Pacific region: China, Hong Kong, Macau, Taiwan, Korea, Vietnam, Thailand, Cambodia, Laos, Malaysia, Indonesia, the Philippines, Singapore, Australia, New Zealand and Japan, which we refer to collectively as the territory. Under the agreement, we granted Zai Lab an exclusive, royalty-bearing license, with the right to sublicense, under our technology to develop, manufacture and sell products containing durlobactam or SUL-DUR, or the licensed products, in the territory. Additionally, we granted Zai Lab a non-exclusive, worldwide license to our technology as required for Zai Lab to practice its exclusive license with respect to the licensed products. We retain the right to use our technology to perform our obligations under the agreement and retain the exclusive right to use our technology in all other countries, including North America and Europe.

Under the agreement, Zai Lab will use commercially reasonable efforts to perform and fund costs associated with our ATTACK Phase 3 registration trial of SUL-DUR in China. Zai Lab is responsible, at its expense, for developing licensed products in the territory, to be coordinated with our continued global efforts with respect to products containing SUL-DUR. Zai Lab must use commercially reasonable efforts to conduct development activities described in the agreed-upon written development plan and to obtain regulatory approval in a specified number of countries in the territory beyond China after regulatory approval of a licensed product in China. Zai Lab is also solely responsible for commercializing licensed products in the territory and must use commercially reasonable efforts to commercialize licensed products for which it has obtained regulatory approval. We are also obligated to supply Zai Lab with the licensed products for clinical development, although Zai Lab may take over manufacturing responsibilities for its own commercialization activities within a specified time period following the effective date of the agreement. Both parties are prohibited from developing and commercializing products in the territory that would compete with the licensed products.

We received an upfront, non-refundable payment of $5.0 million, milestone payments of $7.0 million, research support funding of $0.6 million and certain other reimbursable registration trial costs of $5.4 million, less applicable taxes of $2.2 million from Zai Lab through December 31, 2021. We are eligible to receive up to an aggregate of $91.0 million in additional research and development support payments and development, regulatory and sales milestone payments related to SUL-DUR, imipenem and other combinations with the licensed products. Zai Lab will pay us a tiered royalty equal to a high-single digit to low-double digit percentage based on annual net sales of licensed products in the territory, subject to specified reductions for the market entry of competing products, loss of patent coverage of licensed products and for payments owed to third parties for additional rights necessary to commercialize licensed products in the territory.

Zai Lab may terminate the agreement upon written notice to us at any time and for any reason. Further, we can terminate the agreement if Zai Lab ceases to commercialize the licensed products or challenges any of the patents we licensed to it.

GARDP

In July 2017, we entered into a collaboration agreement with GARDP for the development and commercialization of a product candidate containing zoliflodacin in certain countries. Under the terms of the collaboration agreement, GARDP will use commercially reasonable endeavors to perform and fully fund the Phase 3 registration trial, including the manufacture and supply of the product candidate containing zoliflodacin, in uncomplicated gonorrhea. Both parties are responsible for obtaining marketing authorizations for any future product candidate in such parts of their respective territories as they elect.

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In addition, under the collaboration agreement, we have granted GARDP a worldwide, fully paid, exclusive and royalty-free license, with the right to sublicense, to use our zoliflodacin technology in connection with GARDP’s development, manufacture and commercialization of zoliflodacin in low-income and specified middle-income countries, which we refer to collectively as the GARDP territory. We have retained commercial rights in all other countries worldwide, including the major markets in North America, Europe and Asia-Pacific. We also have retained the right to use and grant licenses to our zoliflodacin technology to perform our obligations under the collaboration agreement and for any purpose other than gonorrhea or community-acquired indications. GARDP will own all intellectual property developed in its performance under the collaboration agreement regarding formulation development of zoliflodacin. In the event we undertake and fund additional efforts outside of the current agreed-upon development plan for zoliflodacin in our territory that leads to the creation of new intellectual property, we will have a right to file and maintain this new intellectual property. In addition, we are obligated to maintain the intellectual property in the countries in the GARDP territory where we filed patent rights at the date of the agreement and, under specified conditions, in our territory, and GARDP must reimburse us for costs and expenses for the maintenance of such intellectual property rights in the countries of the GARDP territory. If we believe the results of the Phase 3 registration trial of zoliflodacin would be supportive of an application for marketing approval, we are obligated to use our best efforts to file an application for marketing approval with the FDA within six months of the completion of the trial and to use commercially reasonable endeavors to file an application for marketing approval with the EMA. Each party is responsible for using commercially reasonable efforts to obtain marketing authorizations for the product candidate in their respective territories.

Both parties have the right to terminate the collaboration agreement with 90 days’ written notice if the other party is in material breach or remains in material breach after a cure period, or with immediate effect upon the occurrence of certain specified events of insolvency. Either party may terminate the collaboration agreement at any time after completion or earlier termination of the Phase 3 registration trial with 12 months’ prior notice. We may terminate the collaboration agreement if GARDP has not achieved certain clinical milestones within a specified time period, unless the nonachievement was due to specified types of delay.

AstraZeneca

In May 2015, we entered into a Business Transfer and Subscription Agreement, or the AstraZeneca Agreement, with AstraZeneca, AstraZeneca UK Limited and AstraZeneca Pharmaceuticals LP, which was amended and restated in March 2016 and further amended in August 2017, pursuant to which we obtained, among other things, worldwide rights to SUL-DUR, ETX0282 and zoliflodacin.

Pursuant to the terms of the AstraZeneca Agreement, we agreed to pay AstraZeneca a one-time milestone payment of $5.0 million within three months of achieving a specified cumulative net sales milestone for SUL-DUR. This milestone payment will be automatically waived should our common stock trade on Nasdaq at or above a specified price at the time we achieve such specified cumulative net sales milestone for SUL-DUR, subject to adjustment for share splits, dividends and other similar events. We are also obligated to pay AstraZeneca a one-time milestone payment of $10.0 million within two years of achieving the first commercial sale of zoliflodacin. If our board of directors deems the milestone payment obligation related to zoliflodacin to be significantly burdensome, AstraZeneca is required to explore in good faith, modifications to the timing of such payment. At our election, either milestone payment may be paid in cash, shares of our common stock, or a combination of cash and stock. Additionally, we are obligated to pay AstraZeneca tiered, single-digit royalties on the annual worldwide net sales of SUL-DUR and, and the lesser of tiered, single-digit royalties on the worldwide annual net sales of zoliflodacin and a specified share of the royalties we receive from sublicensees of zoliflodacin. Royalties on sales of zoliflodacin do not include sales by GARDP in low-income and select middle-income countries. Our obligation to make these royalty payments expires with respect to each product on a country-by-country basis upon the later of (i) the 10 year anniversary of the first commercial sale of a product in each such country or (ii) when the last patent right covering a product expires in each such country.

See Note 9, License and Collaboration Agreements, and Note 14, Commitments, in the accompanying notes to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K for more information on these collaborations and license agreements.

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Intellectual Property

Our commercial success depends in part on our ability to obtain and maintain proprietary or intellectual property protection for our product candidates, our core technologies, and other know-how. To accomplish this we rely on the skills, knowledge and experience of our scientific and technical personnel, as well as that of our advisors, consultants and other contractors. To help protect our proprietary know-how that is not patentable, we rely on trade secret protection and confidentiality agreements to protect our interests. We require our employees, consultants and advisors to enter into confidentiality agreements prohibiting the disclosure of confidential information and requiring disclosure and assignment to us of the ideas, developments, discoveries and inventions important to our business. We file patent applications directed to our key product candidates to establish intellectual property positions. These patent applications are intended to protect new chemical entities relating to these product candidates as well as their manufacturing processes, intermediates and uses in the treatment of diseases.

The intellectual property portfolios for our most advanced product candidates are summarized below.

Durlobactam

Our intellectual property portfolio for our durlobactam program contains patent applications directed to compositions of matter for durlobactam and other chemical analogs, as well as methods of making, referred to as synthetic methods, and methods of use and modes of treatment using durlobactam in combination with one or more antibiotic compounds. As of December 31, 2021, we owned four issued U.S. patents, one pending provisional application, 69 issued foreign patents as well as 12 pending foreign patent applications, of which two are allowed. The issued foreign patents are in several jurisdictions including Australia, the European Union, Canada, China, Hong Kong, Israel, India, Japan, Macau, Mexico, New Zealand, the Philippines, the Russian Federation, Singapore, South Africa, South Korea, Taiwan and the United Kingdom. Issued U.S. and foreign patents and patents issuing from pending U.S. and foreign applications will have expiration dates of April 2033 and November 2035.

Zoliflodacin

Our intellectual property portfolio for zoliflodacin contains patent applications directed to compositions of matter for zoliflodacin and other chemical analogs, as well as synthetic methods and methods of use and modes of treatment. As of December 31, 2021, we owned 7 issued U.S. patents, 71 issued foreign patents as well as six pending foreign patent applications. The issued foreign patents are in several jurisdictions, including Australia, Brazil, Canada, China, Eurasia, the European Union, Hong Kong, India, Israel, Japan, Mexico, New Zealand, Philippines, Singapore, South Africa, South Korea, Taiwan and the United Kingdom. Issued U.S. and foreign patents and patents issuing from pending U.S. and foreign applications have expiration dates of October 2029, January 2034 and May 2035.

ETX0282

Our intellectual property portfolio for our ETX0282 program contains patent applications directed to compositions of matter for the prodrug ETX0282, the active molecule, ETX1317, and other chemical analogs, as well as synthetic methods, and methods of use and modes of treatment using ETX0282 and ETX1317 in combination with one or more antibiotic compounds. As of December 31, 2021, we owned one issued U.S. patent, one pending U.S. application, two issued foreign patents, four allowed foreign patents and 15 pending foreign patent applications, of which one is allowed. Issued U.S. and foreign patents and patents issuing from pending U.S. and foreign applications will have expiration dates of September 2037.

ETX0462

Our intellectual property portfolio for our ETX0462 program contains patent applications directed to compositions of matter for ETX0462 and other chemical analogs, as well as synthetic methods, and methods of use and modes of treatment. As of December 31, 2021, we owned one granted U.S. patent application, one pending U.S. patent application, three issued foreign patents, and 17 pending foreign patent applications. Issued U.S. and foreign patents and patents issuing from pending U.S. and foreign applications will have expiration dates of May 2038.

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Provisional Patents

In addition to the issued and pending patent applications covering our most advanced product candidates, our portfolio also includes one pending PCT application relating to an early stage discovery project.

Trademarks, Trade Secrets and Know-How

Our trademark portfolio currently consists of registered trademark and service mark rights for ENTASIS THERAPEUTICS in several jurisdictions, including the United States, the European Union, Japan, Argentina, Australia, Brazil, Canada, India, Mexico, Norway, the Russian Federation, South Korea, Switzerland, Taiwan, Turkey and the United Kingdom, and pending applications in other jurisdictions. In addition, we have registered trademark and service mark rights for ENTASIS THERAPEUTICS (plus design) in the United States, the European Union, Argentina, Brazil, Canada, Japan, Australia, India, Norway, the Russian Federation, South Korea, Switzerland, Taiwan, Turkey, Mexico and the United Kingdom, and pending applications in other jurisdictions. We have also registered trademark rights for XACDURO and XULDURO in the United States, the European Union, Brazil, China, Hong Kong, India, Macau, New Zealand, the Philippines, Taiwan, the United Arab Emirates, Argentina, Albania, Australia, Egypt, Macedonia, Mexico, Malaysia, Saudi Arabia, the United Kingdom, Belarus, Bosnia-Herzegovina, Cambodia, Indonesia, Israel, Laos, Japan, Moldova, Montenegro, Norway, the Russian Federation, Serbia, Singapore, South Korea, Switzerland, Turkey, Ukraine and Vietnam, and pending applications in other jurisdictions. In connection with the ongoing development and advancement of our products and services in the United States and various international jurisdictions, we routinely seek to create protection for our marks and enhance their value by pursuing trademarks and service marks where available and when appropriate. In addition to patents and trademark protection, we rely upon unpatented trade secrets and know-how and continuing technological innovation to develop and maintain our competitive position. We seek to protect our proprietary information, in part, using confidentiality agreements with our commercial partners, collaborators, employees, and consultants, and invention assignment agreements with our employees. These agreements are designed to protect our proprietary information and, in the case of the invention assignment agreements, to grant us ownership of technologies that are developed through a relationship with a third party. These agreements may be breached, and we may not have adequate remedies for any breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that our commercial partners, collaborators, employees, and consultants use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting know-how and inventions.

Government Regulation

Government authorities in the United States, at the federal, state and local level, and in other countries extensively regulate, among other things, the research, development, testing, manufacture, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, import and export of our products and reimbursement. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulation require the expenditure of substantial time and financial resources.

U.S. Government Regulation

In the United States, the process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local statutes and regulations requires the expenditure of substantial time and financial resources. The failure to comply with the applicable requirements at any time during the product development process, approval process or after approval may subject an applicant to a variety of administrative or judicial sanctions, such as the FDA’s refusal to approve pending applications, withdrawal of an approval, imposition of a clinical hold, issuance of warning letters and untitled letters, product recalls, product seizures, total or partial suspension of production or distribution injunctions, fines, refusals of government contracts, restitution, disgorgement of profits or civil or criminal penalties.

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Approval Processes

In the United States, the FDA regulates drugs under the Federal Food, Drug and Cosmetic Act, or the FDCA, the Public Health Service Act, or PHSA, and implementing regulations. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulation require the expenditure of substantial time and financial resources. Failure to comply with the FDCA and other applicable U.S. requirements at any time during the product development process, approval process or after approval may subject us to a variety of administrative or judicial sanctions, any of which could have a material adverse effect on us. These sanctions could include:

The process required by the FDA before a drug may be marketed in the United States generally involves the following:

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Once a pharmaceutical candidate is identified for development, it enters the preclinical testing stage. Preclinical tests include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies. An IND sponsor must submit the results of the preclinical tests, together with manufacturing information and analytical data, to the FDA as part of the IND. Some preclinical or nonclinical testing may continue even after the IND is submitted. In addition to including the results of the preclinical studies, the IND will also include one or more protocols detailing, among other things, the objectives of the clinical trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated if the first phase lends itself to an efficacy determination. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, places the IND on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin. A clinical hold may occur at any time during the life of an IND and may affect one or more specific studies or all studies conducted under the IND.

All clinical trials must be conducted under the supervision of one or more qualified investigators in accordance with cGCP. They must be conducted under protocols detailing, among other things, the objectives of the trial, dosing procedures, subject selection and exclusion criteria and the safety and effectiveness criteria to be evaluated. Each protocol and any amendments must be submitted to the FDA as part of the IND, and progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more frequently in other situations, including the occurrence of serious adverse events. An IRB at each institution participating in the clinical trial must review and approve the protocol and any amendments before a clinical trial commences or continues at that institution, approve the information regarding the clinical trial and the informed consent form that must be provided to each trial subject or his or her legal representative, monitor the study until completed and otherwise comply with IRB regulations. Information about certain clinical trials must be submitted within specific timeframes to the National Institutes of Health for public dissemination on their ClinicalTrials.gov website.

Human clinical trials are typically conducted in three sequential phases that may overlap or be combined:

Phase 1, Phase 2 and Phase 3 testing may not be completed successfully within any specified period, if at all. The FDA or the sponsor may suspend or terminate a clinical trial at any time for a variety of reasons, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or

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terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients.

During the development of a new drug, sponsors are given opportunities to meet with the FDA at certain points, including prior to submission of an IND, at the end of Phase 2 and before an NDA is submitted. Meetings at other times may also be requested. These meetings can provide an opportunity for the sponsor to share information about the data gathered to date, for the FDA to provide advice and for the sponsor and the FDA to reach agreement on the next phase of development. Sponsors typically use the end-of-Phase 2 meeting to discuss their Phase 2 clinical results and present their plans for the pivotal Phase 3 clinical trial or trials that they believe will support approval of the new drug.

The Pediatric Research Equity Act, or PREA, requires a sponsor to conduct pediatric studies for certain drugs and biologics. Specifically, PREA requires original NDAs, biologic license applications, or BLAs, and supplements thereto for a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration to contain a pediatric assessment unless the sponsor has received a deferral or waiver.

Concurrent with clinical trials, companies usually complete additional animal safety studies and must also develop additional information about the chemistry and physical characteristics of the drug and finalize a process for manufacturing the product in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the drug candidate and the manufacturer must develop methods for testing the quality, purity and potency of the final drugs. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the drug candidate does not undergo unacceptable deterioration over its shelf-life.

The results of product development, preclinical studies and clinical trials, along with descriptions of the manufacturing process, analytical tests conducted on the chemistry of the drug, proposed labeling and other relevant information are submitted to the FDA as part of an NDA requesting approval to market the product for one or more indications. The submission of an NDA is subject to the payment of user fees, but a waiver of such fees may be obtained under specified circumstances. The FDA reviews all NDAs submitted to ensure that they are sufficiently complete for substantive review before it accepts them for filing. It may request additional information rather than accept an NDA for filing. In this event, the NDA must be resubmitted with the additional information. The resubmitted application also is subject to completeness review before the FDA accepts it for filing.

Once the submission is accepted for filing, the FDA begins an in-depth review. NDAs receive either standard or priority review. A drug that, if approved, would represent a significant improvement in the safety or effectiveness of the treatment, prevention or diagnosis of a serious disease or condition may receive priority review. Requests for priority review generally must be submitted at the time of NDA submission. The FDA has agreed to specified performance goals in the review process of NDAs. Under that agreement, 90% of applications seeking approval of new molecular entities, or NMEs, are meant to be reviewed within ten months from the date on which FDA accepts the NDA for filing, and 90% of applications for NMEs that have been designated for “priority review” are meant to be reviewed within six months of the filing date. For applications seeking approval of drugs that are not NMEs, the ten-month and six-month review periods run from the date that FDA receives the application. The review process may be extended by the FDA for three additional months to consider a major amendment to the application following the original submission.

The FDA reviews an NDA to determine, among other things, whether a product is safe and effective for its intended use and whether its manufacturing complies with cGMP requirements to assure and preserve the product’s safety, identity, strength, quality and purity. The FDA may refer the NDA to an advisory committee for review and recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendation.

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Before approving an NDA, the FDA will typically inspect the facility or facilities where the product is manufactured and tested. These pre-approval inspections may cover all facilities associated with NDA submission, including drug component manufacturing (such as active pharmaceutical ingredients), finished drug product manufacturing, and control testing laboratories. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with cGCP. In addition, the FDA may require, as a condition of approval, risk evaluation and mitigation strategies, or REMS (which may include requirements for, restricted distribution and use), enhanced labeling, special packaging or labeling, expedited reporting of certain adverse events, pre-approval of promotional materials, restrictions on direct-to-consumer advertising or commitments to conduct additional research post-approval.

On the basis of the FDA’s evaluation of the NDA and accompanying information, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. If the FDA ultimately decides that the NDA does not satisfy the criteria for approval, the FDA will issue a complete response letter to indicate that the agency will not approve the NDA in its present form. The complete response letter usually describes all of the specific deficiencies in the NDA identified by the FDA. If a complete response letter is issued, the applicant may either resubmit the NDA, addressing all of the deficiencies identified in the letter, or withdraw the application.

Expedited Review and Approval

The FDA has various programs, including Fast Track and priority review, which are intended to expedite or simplify the process for developing and/or reviewing drugs. Even if a drug qualifies for one or more of these programs, the FDA may later decide that the drug no longer meets the conditions for qualification or that the time period for FDA review or approval will not be shortened. Generally, drugs that may be eligible for these programs are those for serious or life-threatening conditions, those with the potential to address unmet medical needs and those that offer meaningful benefits over existing treatments. For example, Fast Track is a process designed to facilitate the clinical development and expedite the review of drugs to treat serious diseases with the potential, based on nonclinical or clinical data, to fill an unmet medical need. Priority review is designed to give drugs that offer a significant improvement in safety or effectiveness of treatment for a serious condition an expedited review within eight months from the completed submission (six months from filing) as compared to a standard review time of twelve months from the completed submission (10 months from filing) for a standard new molecular entity NDA. Although Fast Track and priority review do not affect the standards for approval, the FDA will attempt to facilitate early and frequent meetings with a sponsor of a Fast Track designated drug and expedite review of the application for a drug designated for priority review.

The Generating Antibiotic Incentives Now Act, or GAIN Act, is intended to provide incentives for the development of new QIDPs. A new drug that is designated as a QIDP after a request by the sponsor that is made before an NDA is submitted will be eligible, if approved, for an additional five years of exclusivity beyond any period of exclusivity to which it would have previously been eligible. In addition, a QIDP will receive priority review and qualify for a Fast Track designation. QIDPs are defined as antibacterial or antifungal drugs intended to treat serious or life-threatening infections, including those caused by an antibacterial or antifungal resistant pathogen or qualifying pathogens identified by the FDA. SUL-DUR has been designated by the FDA as a QIDP for the treatment of hospital-acquired and ventilator-acquired bacterial pneumonia and bloodstream infections due to A. baumannii. Zoliflodacin has also been designated as a QIDP by the FDA for the treatment of uncomplicated gonorrhea.

Patent Term Restoration and Data Exclusivity

Depending upon the timing, duration and specifics of FDA approval of the use of our drugs, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch-Waxman Amendments. As noted above, the Hatch-Waxman Amendments permit a patent restoration term of up to five years for a single patent for an approved product as compensation for patent term lost during product development and the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date and only those claims covering such approved drug product, a method for using it or a method for manufacturing it may be extended. Only one patent applicable to an approved drug is eligible for the extension and the application for the

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extension must be submitted prior to the expiration of the patent. The USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we may apply for restoration of patent term for our currently owned or licensed patents to add patent life beyond its current expiration date, depending on the expected length of the clinical trials and other factors involved in the filing of the relevant NDA.

Data exclusivity provisions under the FDCA also can delay the submission or the approval of certain applications. The FDCA provides a five-year period of non-patent data exclusivity within the United States to the first applicant to gain approval of an NDA for a new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or ion responsible for the action of the drug substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application, or ANDA, or a 505(b)(2) NDA submitted by another company using the drug entitled to data exclusivity as the reference listed drug, or RLD. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement. The FDCA also provides three years of data exclusivity for an NDA, 505(b)(2) NDA or supplement to an existing NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application, for example, for new indications, dosages or strengths of an existing drug. This three-year exclusivity covers only the use or conditions of use associated with the new clinical investigations and does not prohibit the FDA from approving ANDAs for drugs containing the original active agent for other uses or conditions of use. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA. However, an applicant submitting a full NDA would be required to conduct its own preclinical and clinical studies in support of its application or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

In addition, as described above, under the GAIN Act a new drug that is designated as a QIDP is eligible for an additional five years of exclusivity to be added to certain other exclusivity periods that the application may qualify for upon approval, specifically five-year exclusivity, three-year exclusivity, and orphan exclusivity.

Pediatric Exclusivity

The Best Pharmaceuticals for Children Act provides for an additional six months of exclusivity, which is added on to patent and exclusivity periods in effect at the time the pediatric exclusivity award is granted, if a sponsor conducts clinical trials in children in response to a written request from the FDA, or a Written Request. The FDA may request studies on approved indications in separate Written Requests. The issuance of a Written Request does not require the sponsor to undertake the described studies. To date, we have not received any Written Requests.

Post-approval Requirements

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems, including safety issues, with a product may result in restrictions on the product or even complete withdrawal of the product from the market. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further FDA review and approval. In addition, the FDA may require testing and surveillance programs to monitor the effect of approved products that have been commercialized, and the FDA has the power to prevent or limit further marketing of a product based on the results of these post-marketing programs. The FDA and other authorities also strictly regulate the promotional claims that may be made about prescription products. Under the FDCA the sponsor of an approved drug in the United States may not promote that drug for unapproved, or off-label, uses, although a physician may prescribe a drug for an off-label use in accordance with the practice of medicine. If we are found to have promoted off-label uses, we may be subject to significant liability, including sanctions, civil and criminal fines and penalties, and injunctions prohibiting us from engaging in specified promotional conduct.

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Moreover, any drug products manufactured or distributed pursuant to FDA approvals are subject to continuing regulation by the FDA, including, among other things:

Drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and some state agencies for compliance with cGMP requirements and other laws.

Failure to comply with the FDCA and other applicable U.S. requirements at any time during the product development process, approval process or after approval may subject us to a variety of administrative or judicial sanctions, any of which could have a material adverse effect on us. These sanctions could include:

From time to time, legislation is drafted, introduced and passed in Congress that could significantly change the statutory provisions governing the approval, manufacturing and marketing of products regulated by the FDA. In addition, FDA regulations and guidance are often revised or reinterpreted by the agency in ways that may significantly affect our business and our products. It is impossible to predict whether legislative changes will be enacted, or FDA regulations, guidance or interpretations changed or what the impact of such changes, if any, may be.

Foreign Regulation

In addition to regulations in the United States, we will be subject to a variety of foreign regulations governing clinical trials and commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we must obtain approval by the comparable regulatory authorities of foreign countries or economic areas, such as the EU, before we may commence clinical trials or market products in those countries or areas. The approval process

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and requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from place to place, and the time may be longer or shorter than that required for FDA approval.

Under EU regulatory systems, a company may submit marketing authorization applications under the centralized, decentralized or mutual recognition procedures, or under the purely national route of approval. The centralized procedure is compulsory for medicinal products produced by biotechnology or those medicinal products containing new active substances for specific indications such as the treatment of acquired immune deficiency syndrome, or AIDS, cancer, neurodegenerative disorders, diabetes, viral diseases, and designated orphan medicines, and is optional for other medicines that are highly innovative. Under the centralized procedure, a marketing application is submitted to the European Medicines Agency, or EMA, where it will be evaluated by the relevant scientific committee, in most cases the Committee for Medicinal Products for Human Use, and a favorable opinion typically results in the grant by the European Commission of a single marketing authorization that is valid for all EU member states and, by extension (after national implementing measures), in Norway, Iceland and Liechtenstein. In general, an initial marketing authorization is valid for five years, but once renewed is usually valid for an unlimited period. The decentralized procedure allows marketing authorization applications to be submitted simultaneously in two or more EU member states, whereas the mutual recognition procedure must be used if the product has already been authorized in at least one other EU member state. Both the decentralized and mutual recognition procedures provide for approval by one or more “concerned” member states based on an assessment of an application performed by one-member state, known as the “reference” member state.

Under the decentralized approval procedure, an applicant submits an application, or dossier, and related materials to the reference member state and concerned member states. The reference member state prepares a draft assessment and drafts of the related materials within 120 days after receipt of a valid application. Within 90 days of receiving the reference member state’s assessment report, each concerned member state must approve the assessment report and related materials, unless they identify a serious risk to public health. Under the mutual recognition procedure, the concerned member states have the same 90-day period to recognize the marketing authorization in the reference member state. In either case, concerns about serious risks to public health escalate through the relevant EMA scientific committees, and the disputed points may eventually result in a consensus opinion from the Committee for Medicinal Products for Human Use that is referred to the European Commission, whose decision is binding on all member states. The purely national procedure results in a marketing authorization in a single EU member state.

Following the result of a referendum in 2016, the United Kingdom left the EU on January 31, 2020, and as of January 1, 2021, the United Kingdom and EU operate separate regulatory regimes. The UK and EU announced on December 24, 2020, that they had agreed a Trade and Cooperation Agreement, or TCA, to govern their future relationship. The TCA remains provisional until formally ratified by the EU, which is expected to occur in early 2021. The TCA sets out the new arrangements for trade of goods, including medicines and medical devices, which aims to ensure goods continue to flow between the EU and the UK and also has implications for product regulation and mutual recognition.

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As a result of the United Kingdom’s departure from the EU, if a company wishes to sell its products in the United Kingdom, it will need to seek and maintain appropriate national marketing authorizations. The TCA does not provide for wholesale mutual recognition of the regulatory regimes and so products exported from the UK to the EU must comply with the EU’s regulatory requirements. In the pharmaceutical context, this has had a number of implications. From January 31, 2020, the UK no longer participated in EU institutions and their decision-making, including approval decisions under the centralized procedure. Moreover, the movement of finished pharmaceutical products into the EU from the UK is treated as an import from a third country. Since the TCA does not provide for mutual recognition of batch testing and release, products must be quality control tested and released in the EU. However, the UK will unilaterally waive batch testing requirements for UK imports from the EU for products placed on the market before January 2023. It remains to be seen how these developments will impact regulatory requirements for product candidates and products in the United Kingdom.

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Reimbursement

Significant uncertainty exists as to the coverage and reimbursement status of products approved by the FDA and other government authorities. Sales of products will depend, in part, on the extent to which third-party payors, including government health programs in the United States such as Medicare and Medicaid, commercial health insurers and managed care organizations, provide coverage, and establish adequate reimbursement levels for, such products. The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is approved. Third-party payors are increasingly challenging the prices charged, examining the medical necessity, and reviewing the cost-effectiveness of medical products and services and imposing controls to manage costs. Third-party payors may limit coverage to specific products on an approved list, or formulary, which might not include all the approved products for a particular indication.

To secure coverage and reimbursement for any product that might be approved for sale, a company may need to conduct expensive pharmacoeconomic studies to demonstrate the medical necessity and cost effectiveness of the product, in addition to the costs required to obtain FDA or other comparable regulatory approvals. Nonetheless, product candidates may not be considered medically necessary or cost effective. Additionally, a payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved. Further, one payor’s determination to provide coverage for a drug product does not ensure that other payors will also provide coverage for the drug product. Third-party reimbursement may not be sufficient to maintain price levels high enough to realize an appropriate return on investment in product development.

Health Care Laws Governing Interactions with Healthcare Providers

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws restrict our business activities, including certain marketing practices. These laws include, without limitation, anti-kickback laws, false claims laws, data privacy and security laws, as well as transparency laws regarding payments or other items of value provided to healthcare providers.

The federal Anti-Kickback Statute prohibits, among other things, knowingly and willfully offering, paying, soliciting or receiving remuneration to induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any healthcare item, good, facility or service reimbursable under Medicare, Medicaid or other federal healthcare programs. The term “remuneration” has been broadly interpreted to include anything of value. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on the one hand and prescribers, purchasers and formulary managers, among others, on the other. Although there are several statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution or other regulatory sanctions, the exceptions and safe harbors are drawn narrowly, and practices that involve remuneration that are alleged to be intended to induce prescriptions, purchases or recommendations may be subject to scrutiny if they do not qualify for an exception or safe harbor. Failure to meet all requirements of a particular applicable statutory exception or regulatory safe harbor does not make the conduct per se illegal under the federal Anti-Kickback Statute. Instead, the legality of the arrangement will be evaluated on a case-by-case basis based on a cumulative review of all its facts and circumstances. Several courts have interpreted the statute’s intent requirement to mean that if any one purpose of an arrangement involving remuneration is to induce referrals of federal healthcare covered business, the federal Anti-Kickback Statute has been violated. Additionally, the intent standard under the federal Anti-Kickback Statute was amended by the Patient Protection and Affordable Care Act of 2010, as amended by the Health Care and Education Reconciliation Act of 2010, collectively the Affordable Care Act, or ACA, to a stricter standard such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the ACA codified case law that a claim for payment for items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act.

Federal false claims laws, including the civil False Claims Act, and civil monetary penalties laws prohibit any person or entity from, among other things, knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making, or causing to be made, a false statement to have a claim paid. Pharmaceutical and other healthcare companies have been prosecuted under these laws for, among other things, allegedly inflating drug prices they report to pricing services, which in turn were used by the government to set Medicare

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and Medicaid reimbursement rates, and for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. In addition, certain marketing practices, including off-label promotion, have also been alleged to violate false claims laws.

The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created additional federal criminal and civil statutes that prohibit among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. As with the federal Anti-Kickback Statute, the ACA amended the intent standard for certain healthcare fraud under HIPAA such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it to have committed a violation.

In addition, we may be subject to data privacy and security regulations promulgated by both the federal government and the states in which we conduct our business. HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and its implementing regulations, impose certain requirements on covered entities (i.e., certain healthcare providers, health plans and healthcare clearinghouses) relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s security standards directly applicable to business associates, independent contractors or agents of covered entities that receive or obtain protected health information in connection with providing a service on behalf of a covered entity. HITECH also created four new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions.

Additionally, the federal Physician Payments Sunshine Act, created under the ACA, and its implementing regulations, require certain manufacturers of drugs, devices, biologicals and medical supplies for which payment is available under Medicare, Medicaid or the children’s health insurance program (with certain exceptions) to annually report information related to certain payments or other transfers of value provided to covered recipients, including physicians, as defined by such law, and teaching hospitals, or to entities or individuals at the request of, or designated on behalf of, the physicians and teaching hospitals’ covered recipients and information related to certain ownership and investment interests held by physicians and their immediate family members.

Finally, the majority of states also have statutes or regulations similar to the aforementioned federal laws, some of which are broader in scope and apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor. Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government. In addition, some state laws require drug manufacturers to report information related to payments to clinicians and other healthcare providers or marketing expenditures and drug pricing. Further, some state and local laws require the licensure of pharmaceutical sales representatives. State and foreign laws also govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Healthcare and Other Reform

In the United States, there have been and continue to be a number of significant legislative initiatives to contain healthcare costs. Federal and state governments continue to propose and pass legislation designed to reform delivery of, or payment for, healthcare, which include initiatives to reduce the cost of healthcare. For example, in March 2010, the United States Congress enacted the ACA, which expanded health care coverage through Medicaid expansion and the implementation of the individual mandate for health insurance coverage and which included changes to the coverage and reimbursement of drug products under government healthcare programs. Under the Trump administration, there were ongoing efforts to modify or repeal all or certain provisions of the ACA. For example, tax reform legislation was enacted at the end of 2017 that eliminated the tax penalty established under the ACA for individuals who do not maintain

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mandated health insurance coverage beginning in 2019. The ACA has also been subject to judicial challenge. In December 2018, a federal district court, in a challenge brought by a number of state attorneys general, found the ACA unconstitutional in its entirety because, once Congress repealed the individual mandate provision, there was no longer a basis to rely on Congressional taxing authority to support enactment of the law. In December 2019, the federal appellate court upheld the district court ruling that the individual mandate was unconstitutional and remanded the case back to the district court to determine whether the remaining provisions of the ACA are invalid as well. The case has been appealed to the U.S. Supreme Court where a ruling remains pending.

There were other reform initiatives under the former Trump Administration, including initiatives focused on drug pricing. For example, the Bipartisan Budget Act of 2018 contained various provisions that affect coverage and reimbursement of drugs, including an increase in the discount that manufacturers of Medicare Part D brand name drugs must provide to Medicare Part D beneficiaries during the coverage gap from 50% to 70% starting in 2019. As another example, in 2018, President Trump and the Secretary of the HHS, released a “blueprint” to lower prescription drug prices and out-of-pocket costs. Certain proposals in the blueprint, and related drug pricing measures proposed since the blueprint, could cause significant operational and reimbursement changes for the pharmaceutical industry. HHS has solicited feedback on some of these measures and, at the same, has implemented others under its existing authority. On November 20, 2020, CMS issued an interim final rule through the CMS Innovation Center whereby Medicare Part B reimbursement for “certain high-cost prescriptions drugs” would be no more than most-favored-nation price (i.e., the lowest price) after adjustments, for a pharmaceutical product that the drug manufacturer sells in a member country of the Organization for Economic Cooperation and Development that has a comparable per-capita gross domestic product. On December 28, 2020, the United States District Court in Northern California issued a nationwide preliminary injunction against implementation of the interim final rule. While some of these and other measures may require additional authorization to become effective, members of Congress and the new Biden administration have indicated that lowering prescription drug prices is a priority, but it is not yet clear what steps the Biden Administration will take or whether such steps will be successful.

There have also been recent state legislative efforts to address drug costs, which generally have focused on increasing transparency around drug costs or limiting drug prices and address price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

In 2019, the DISARM Act of 2019 was introduced in Congress as new legislation to provide financial incentives for pharmaceutical companies to develop new antibiotics. This new legislation was guided by input from the IDSA and will help to ensure that patients can access new antibiotics when they are clinically appropriate, require hospitals to establish antibiotic stewardship programs, and spur improved reporting of antibiotic use and resistance to more rapidly identify challenges and inform best practices. More recently, this legislation was reintroduced in the U.S. House of Representatives in June 2021 which aims to amend title XVIII of the Social Security Act to encourage the development and use of DISARM antimicrobial drugs, and for other purposes.

General legislative cost control measures may also affect reimbursement for our product candidates. The Budget Control Act, as amended, resulted in the imposition of 2% reductions in Medicare, but not Medicaid, payments to providers in 2013 and will remain in effect through 2029 unless additional Congressional action is taken. There was a temporary suspension of the 2% reduction during the pandemic; that temporary suspension is scheduled to expire on March 31, 2021. Any significant spending reductions affecting Medicare, Medicaid or other publicly funded or subsidized health programs that may be implemented and/or any significant taxes or fees that may be imposed on us could have an adverse impact on our results of operations.

Legislation was introduced to the U.S. Senate in September 2020 which aims to reinvigorate innovation for the development of new antibiotics through a subscription contract program managed by HHS. The PASTEUR Act was introduced to provide a mechanism for funding designated ‘critical need antimicrobial’ drugs post FDA approval. In return, patients covered by federal insurance programs will receive these drugs at no cost. These Contracts under the PASTEUR Act could range from $750 million to $3 billion in value. It is unclear when or if the PASTEUR Act or similar incentive programs will become law. In October 2021, the PACCARB authored a letter to the Honorable Xavier

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Becerra, Secretary, Department of Health and Human Services recommending the passage of both DISARM and PASTEUR and the antimicrobial stewardship provisions contained within each act.

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Adoption of new legislation at the federal or state level could affect demand for, or pricing of, our current or future products if approved for sale. We cannot, however, predict the ultimate content, timing or effect of any changes to the ACA or other federal and state reform efforts. There is no assurance that federal or state health care reform will not adversely affect our future business and financial results.

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Human Capital

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As of December 31, 2021, we employed 51 people. We have no hourly employees. Thirteen of our employees work in our laboratory facilities while the remaining are office personnel. None of our employees are represented by a labor union or covered by a collective bargaining agreement.

The Human Resources Associate is responsible for developing and executing our human capital resources strategy. This includes the attraction, acquisition, development, engagement of talent and the design of employee compensation and benefits programs. The Chief Executive Officer regularly updates our board of directors and our committees on the operation and status of these human capital trends and activities.

Diversity, Equity and Inclusion

We have created an environment that fosters individual development while maintaining consistency in our corporate values and code of conduct. In 2020, we signed MassBio's Open Letter 2.0 ⸻ The CEO Pledge for a More Equitable & Inclusive Life Sciences Industry. By signing this Pledge, we are committing ourselves to take actions to foster a more diverse and inclusive environment in the life sciences industry. We continue to offer seminars from external consultants on diversity, equity and inclusion, or DEI, best practices and provide ongoing support to an internal discussion group focused on DEI topics important to the workplace.

Health, Safety and Wellness

We strive to provide pay, benefits and other employee services that are competitive to market in the life sciences industry and create incentives to attract and retain employees. Our compensation package includes market-competitive pay, stock options and restrictive stock units, bonuses, employee spot awards, health care and retirement benefits, paid time off and family leave. We utilize third party consultants to review and update our compensation practices annually. We are also committed to the continued development of its people, providing opportunities for employees to further their career development through internal training and education programs and third party online training programs. We have been certified as a “Great Place to Work” for the past three years and we believe our relationship with our employees to be good.

Corporate and Other Information

Entasis Therapeutics Holdings Inc. was incorporated under the laws of the State of Delaware in March 2018. Our shares are listed on The Nasdaq Global Market, where our trading symbol is ETTX. Our principal executive offices are located at 35 Gatehouse Drive, Waltham, Massachusetts 02451 and our telephone number is (781) 810-0120.

Entasis, the Entasis logo and other trademarks or service marks of Entasis Therapeutics Holding, Inc. appearing in this Annual Report on Form 10-K are the property of Entasis. This Annual Report on Form 10-K contains additional trade names, trademarks, and service marks of other companies. We do not intend our use or display of other companies’ trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of us, by these other companies. Other trademarks appearing in this Annual Report on Form 10-K are the property of their respective holders.

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Available Information

You may read our SEC filings, including our proxy statements, annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act, over the internet at the SEC’s website at www.sec.gov. We also maintain a website at www.entasistx.com, at which you may access these materials free of charge as soon as reasonably practicable after they are electronically filed with, or furnished to, the SEC. The information contained in, or that can be accessed through, our website is not part of, and is not incorporated into, this Annual Report on Form 10-K.

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Risks Related to Our Dependence on Third Parties

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Risks Related to the Commercialization of Our Product Candidates

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Risks Related to Our Business and Managing Our Growth

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Risks Related to Our Intellectual Property

Risks Related to Ownership of Our Common Stock

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Risks Resulting from the Current Global Pandemic

The COVID-19 pandemic has had, and may continue to have, an adverse effect on our business, development programs and access to capital, and additional COVID-19 outbreaks may have a similar or worse impact on us.

The COVID-19 pandemic has had, and will continue to have, an unprecedented impact on the U.S. economy in general and large and small businesses in particular. Virus mutations have resulted in repeated surges in infection rates, resulting in disruptions to business operations as employers and workforces adapt to new working conditions and requirements. Since the onset of the pandemic, the majority of our employees have been working remotely and our laboratory workers have operated in reduced and/or staggered shifts. As regulatory agencies prioritize the review of therapies with the potential to minimize the extent and/or severity of the pandemic, review of regulatory submissions of other therapeutic products may experience delays. As healthcare systems focus on patients affected by the COVID-19 pandemic, global clinical trials, including our ongoing Phase 3 registration trial with zoliflodacin, have seen declines in activity or have been suspended temporarily. For instance, for the Phase 3 registration trial for zoliflodacin some clinical sites in high COVID-19 impact areas, have experienced periodic delays in new patient enrollment due to redirection of resources or hospital access restrictions as required by local conditions. GARDP, with our full agreement, had temporarily paused patient enrollment and activation of new clinical trial sites in March 2020. In June 2020, GARDP resumed patient enrollment into the Phase 3 registration trial at U.S. sites and ten new clinical trial sites were activated in the Netherlands (1), South Africa (5), Thailand (3) and the U.S. (1) during 2021. While we have not experienced material disruptions in our supply chain to date due to the COVID-19 pandemic, it may in the future impact our ability to procure resources, raw materials or components necessary for our development programs. For example, our contract manufacturing partners may see pandemic related disruptions, which could impede their ability to produce supply of our product candidates sufficient for further clinical testing and/or commercialization. As a result of the unpredictability surrounding the COVID-19 pandemic, the timelines for completion of our planned regulatory filing, registration trial and earlier-stage development programs may be materially impacted. Significant delays in the development of any of our product candidates will be costly and could adversely affect our ability to obtain regulatory approval for and successful commercialization of our product candidates. The nature and extent of the impact remains uncertain as the duration of the COVID-19 pandemic and the time needed for businesses and healthcare systems to recover remains unknown. Although we are continuing to actively monitor and assess the effects of the COVID-19 pandemic on our business and development programs, the ultimate impact of the COVID-19 pandemic is highly uncertain and subject to change.

Our ability to raise additional capital may be adversely impacted by worsening global economic conditions and the continuing disruptions to, and volatility in, financial markets in the United States and worldwide resulting from the ongoing COVID-19 pandemic. The continuation of prolonged adverse economic conditions (including due to a resurgence or subsequent waves of COVID-19 infections and delays in completing the distributions of COVID-19 vaccines) could limit our access to financial resources from the capital markets and other sources. 

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We are not yet certain about the full extent of the long-term potential impact of COVID-19 on our business, development programs and access to capital. To the extent COVID-19 continues to adversely affect our business, financial condition and results of operations, as well as global economic conditions more generally, it may also heighten many of the other risk factors described in this Annual Report on Form 10-K.

Risks Related to Our Financial Position and Capital Needs

We have incurred significant losses since our inception. We expect to incur losses over the next several years and may never achieve or maintain profitability.

We are an advanced, clinical-stage, biopharmaceutical company with a limited operating history. We have not generated any revenue from the sale of products and have incurred losses in each year since our inception in 2015. Our net loss was $47.1 million and $50.5 million for the years ended December 31, 2021 and 2020, respectively. As of December 31, 2021, we had an accumulated deficit of $231.6 million. We have funded our operations to date primarily with proceeds from the sale of common stock, warrants and convertible preferred stock. We have also either directly received funding or financial commitments from, or have had our program activities conducted and funded by, the U.S. government through our arrangements with the NIH, NIAID, CARB-X, and the DOD, and have received non-profit awards from GARDP, and upfront and milestone payments of $12.0 million, research support funding of $0.6 million and other reimbursable registration trial costs of $5.4 million, less applicable taxes, from our license and collaboration agreement with Zai Lab.

We have devoted substantially all of our financial resources and efforts to research and development, including preclinical studies and clinical trials. While we are advancing development of our product candidates, we have not completed development of any drugs. We expect to continue to incur significant expenses and operating losses over the next several years. Our net losses may fluctuate significantly from quarter to quarter and year to year. We anticipate that our expenses will increase substantially as we:

To become and remain profitable, we and our collaborators must succeed in developing and eventually commercializing drugs that generate significant revenue. This will require us, and in some cases our collaborators, to be successful in a range of challenging activities, including completing preclinical studies and clinical trials of our product

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candidates, obtaining regulatory approval, manufacturing, marketing and selling any products for which we may obtain regulatory approval, as well as discovering and developing additional product candidates. We may never succeed in these activities and, even if we do, may never generate revenues that are significant enough to achieve profitability.

Because of the numerous risks and uncertainties associated with drug development, we are unable to accurately predict the timing or amount of expenses or when, or if, we will be able to achieve profitability. If we are required by regulatory authorities to perform studies in addition to those currently completed or expected, or if there are any delays in the initiation and completion of our clinical trials, the submission or approval of our regulatory submissions, or the development of any of our product candidates, our expenses could increase.

Even if we achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would depress the value of our common stock and could impair our ability to raise capital, expand our business, maintain our research and development efforts or continue our operations. A decline in the value of our common stock could also cause you to lose all or part of your investment.

Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future viability.

We commenced active operations in 2015, and our operations to date have been largely focused on raising capital, identifying and developing our product candidates and preclinical program, broadening our expertise in the development of our product candidates, and undertaking preclinical studies and conducting clinical trials. As an organization, we have not yet demonstrated an ability to successfully file an NDA and obtain regulatory approval, manufacture a commercial-scale product or arrange for a third party to do so on our behalf, or conduct, or secure a collaborator to conduct, sales and marketing activities necessary for successful commercialization. Consequently, any predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history.

We may encounter unforeseen expenses, difficulties, complications, delays and other known or unknown factors in achieving our business objectives. We will need to transition at some point from a company with a research and development focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

We expect our financial condition and operating results to continue to fluctuate significantly from quarter to quarter and year to year due to a variety of factors, many of which are beyond our control. Accordingly, you should not rely upon the results of any quarterly or annual periods as indications of future operating performance.

We require substantial additional funding to be able to continue as a going concern and to pursue our business objectives. If we are unable to raise capital when needed, we could be forced to delay, reduce or altogether cease our product development programs or commercialization efforts.

Absent any additional financing, our cash and cash equivalents as of December 31, 2021 together with the $15.0 million received in February 2022 from Innoviva as part of the securities purchase agreement, or the Fourth Securities Purchase Agreement, are expected to fund our operating expenses and capital expenditure requirements through the end of the third quarter of 2022 but are not sufficient to sustain our operations in the long term. As a result, our management has concluded that there is substantial doubt about our ability to continue as a going concern for the one-year period following the issuance of our financial statements for the year ended December 31, 2021. We will need to obtain substantial additional funding in connection with our continuing operations, which cannot be assured. Our future capital requirements will depend on many factors, including:

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Identifying potential product candidates and conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain regulatory approval and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of drugs that we do not expect to be commercially available until at least 2023, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all. In addition, we may seek additional capital due to favorable market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce the scope of, suspend or altogether cease our research and development programs or future commercialization efforts. We can provide no assurance that such actions would be adequate to sustain our operations in the long-term, and such actions may adversely affect our ability to grow in the future.

Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to relinquish rights to our technologies or product candidates.

Until such time, if ever, as we can generate substantial product revenue, we expect to finance our cash needs through a combination of equity offerings, debt and/or royalty financings and potential collaboration, license and development agreements and government/non-profit grants and awards. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect your rights as a stockholder. Debt or royalty financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.

If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may be required to relinquish valuable rights to, or control of, our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our drug development or future commercialization efforts or grant rights to a third party to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

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Provisions in the Company’s securities purchase agreement with Innoviva Inc. and related documents may make it more difficult for us to raise additional capital to fund our operations.

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Provisions in the agreements we entered into in April 2020 in connection with the first private placement transaction, or the First Private Placement, may deter or prevent us from raising additional capital to fund our operations as and when needed. For example, the Investor Rights Agreement we entered into with Innoviva, or the Investor Rights Agreement, in connection with the First Private Placement provides participation rights for Innoviva to participate pro rata in our future offerings of securities. These and other provisions in the First Private Placement documents could deter or prevent us from raising additional capital. Our failure to raise capital as and when needed would have a negative effect on our financial condition and our ability to develop and commercialize our pipeline and otherwise pursue our business strategy and we may be unable to continue as a going concern.

Our ability to use our net operating loss carryforwards and certain other tax attributes may be limited.

As of December 31, 2021, we had U.S. federal and state net operating loss carryforwards, or NOLs, of $166.3 million and $167.4 million, respectively. We do not anticipate generating revenue from sales of products until 2023 at the earliest, if ever, and we may never achieve profitability. Unused NOLs generated in tax years ending on or prior to December 31, 2017 will carry forward for twenty years and, subject to the limitations as a result of an ownership change described below, will be available to offset future taxable income, if any, until they expire. Unused tax losses generated after December 31, 2017, will not expire and may be carried forward indefinitely, but will be deductible only to the extent of 80% of current taxable income in any given year (after deduction, if any of any pre-2018 NOLs). It is uncertain if and to what extent various U.S. states will conform to the U.S. federal income tax treatment of post-2017 NOLs.

Sections 382 and 383 of the U.S. Internal Revenue Code of 1986, as amended, which we refer to as the Code, provide additional limitations on the use of NOLs if a corporation undergoes an “ownership change.” This is defined as a greater than 50 percentage point shift (by value) in the corporation’s equity ownership by certain stockholders, generally over a three-year period. After an ownership change, a corporation’s ability to use its pre-change NOLs and other pre-change tax attributes to offset its post-change taxable income or tax liabilities, both as determined for U.S. federal income tax purposes, is limited. We have experienced ownership changes in the past, and we may experience further ownership changes in the future as a result of future shifts in our share ownership, some of which shifts are outside our control. Accordingly, our ability to use our pre-change NOLs to offset taxable income, as determined for U.S. federal income tax purposes, may be subject to limitations. Similar limitations under U.S. state tax law may also apply to our use of accumulated state tax attributes, including our state NOLs. In addition, at the state level, there may be periods during which the use of NOLs is suspended or otherwise limited, which could accelerate or permanently increase state taxes owed. As a result, even if we attain profitability, we may be unable to use a material portion of our NOLs and other tax attributes, which could negatively impact our future cash flows.

Risks Related to the Development of Our Product Candidates and Preclinical Program

We depend to a large degree on the success of our most advanced product candidates, which remain in clinical development and for which we have not yet successfully submitted an NDA. If we do not successfully complete our clinical trials, submit our NDA or obtain regulatory approval for and successfully generate revenue from one or more of our product candidates or if we experience significant delays in doing so, we may never become profitable.

We currently have no products approved for sale and have invested a significant portion of our efforts and financial resources on the development of our product candidates for the treatment of serious infections caused by multidrug-resistant Gram-negative bacteria. We expect that a substantial portion of our efforts and expenses over the next few years will be devoted to the submission of applications for marketing authorization and potential FDA approval of SUL-DUR as well as development of our current product candidates. As a result, our business currently depends heavily on the successful development, regulatory approval and, if approved, commercialization of our product candidates. We cannot be certain that our product candidates will receive regulatory approval or will be successfully commercialized even if they receive regulatory approval. The research, development, manufacturing, safety, efficacy, labeling, approval, sale, marketing and distribution of our product candidates are, and will remain, subject to comprehensive regulation by the FDA, the EMA, and comparable foreign regulatory authorities. Before obtaining

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regulatory approvals for the commercial sale of any product candidate, we must demonstrate through preclinical studies and clinical trials that the product candidate is safe and effective for use in each target indication. Drug development is a long, expensive and uncertain process, and delay or failure can occur at any stage of any of our clinical trials. Failure to obtain regulatory approval for our product candidates in the United States will prevent commercialization and marketing of our product candidates. The success of our product candidates and preclinical programs will depend on several additional factors, including:

If we do not achieve one or more of these factors in a timely manner or at all, our product candidates could experience significant delays to market or result in unsuccessful commercialization which would harm our business. If we do not successfully develop and commercialize product candidates or collaborate with others to do so, we will not be able to obtain product revenue in future periods, which could significantly harm our financial position and adversely affect the trading price of our common stock.

Success in preclinical studies or clinical trials may not be indicative of results in current or future clinical trials.

Success in preclinical testing and early clinical trials does not ensure that later clinical trials will generate the same results or otherwise provide adequate data to demonstrate the efficacy and safety of a product candidate. Our product candidates may fail to show the necessary safety and efficacy in clinical development despite positive results in preclinical studies or having successfully advanced through initial clinical trials.

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In addition, the design of a clinical trial can determine whether its results will support approval of a product and flaws in the design of a clinical trial may not become apparent until the clinical trial is well advanced. As an organization, we have limited experience designing clinical trials and may be unable to design and execute a clinical trial to support regulatory approval. There is a high failure rate for drugs and biologic products proceeding through clinical trials. Many companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials even after achieving promising results in preclinical testing and earlier-stage clinical trials. Data obtained from preclinical and clinical activities are subject to varying interpretations, which may delay, limit or prevent regulatory approval. In addition, we may experience regulatory delays or rejections because of many factors, including changes in regulatory policy during the period of our product candidate development. Any such delays could negatively impact our business, financial condition, results of operations and prospects.

If clinical trials of any of our product candidates fail to demonstrate safety and efficacy to the satisfaction of the FDA, the EMA or other comparable regulatory authorities, or do not otherwise produce favorable results, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of that product candidate.

We, or our potential collaborates, may not commercialize, market, promote, or sell any product candidate without obtaining marketing approval from the FDA, the EMA or other comparable regulatory authority, and we may never receive such approvals. Even if our product candidates appear sufficiently effective and/or safe in patients in well-controlled clinical trials, it is impossible to predict if or when these product candidates will receive regulatory approval. Before obtaining marketing approval from regulatory authorities for the sale of any product candidate, we must complete preclinical development and then conduct extensive clinical trials to demonstrate the safety and efficacy of our product candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and is uncertain as to outcome. A failure of one or more clinical trials can occur at any stage of testing. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their products.

We may experience numerous unforeseen events prior to, during, or because of, clinical trials that could delay or prevent our ability to receive marketing approval or commercialize our product candidates, including:

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If we are required to conduct additional clinical trials or other testing of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials or other testing of those product candidates, if the results of these trials or tests are not positive or are only modestly positive or if there are safety concerns, we may:

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Our product development costs may also increase if we experience delays in testing and we may be required to obtain additional funds to complete clinical trials. We do not know whether any of our preclinical studies or clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all. Significant preclinical study or clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize our product candidates. In addition, many of the factors that cause, or lead to, delays of clinical trials may ultimately lead to the denial of regulatory approval of a product candidate.

If we are not successful in discovering, developing, and commercializing additional product candidates, our ability to expand our business and achieve our strategic objectives would be impaired.

Although a substantial amount of our effort will focus on the continued clinical testing and potential regulatory approval of our product candidates, an element of our strategy is to develop and commercialize, either by ourselves or with a collaborator, our highly differentiated, targeted product candidates to treat serious infections caused by multidrug-resistant Gram-negative bacteria and discover and develop novel product candidates in other therapeutic areas. We are seeking to do so by utilizing our discovery research experience and capabilities to design active new compounds that target causative mechanisms of disease. To date we have focused our clinical development on multidrug-resistant pathogens and plan to leverage this experience in the development and regulatory paths available for first-in-class or best-in-class molecules in other therapeutic areas. Research efforts to identify and develop product candidates require substantial technical, financial and human resources, whether or not any product candidates are ultimately identified. Our research programs may initially show promise in identifying potential product candidates, yet fail to yield product candidates for clinical development for many reasons, including the following:

If we fail to develop and successfully generate revenue from other current and future product candidates, our business and future prospects may be harmed, and our business will be more vulnerable to any problems that we or potential collaborates may encounter in developing and commercializing our current product candidates.

If we or our collaborators experience delays or difficulties in the enrollment of patients in clinical trials, our receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate, continue or complete clinical trials of our product candidates that we develop if we and our collaborators are unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required by the FDA, the EMA or other comparable regulatory authority. We have limited experience enrolling patients in our clinical trials and cannot predict how successful we will be in enrolling patients in future clinical trials.

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For instance, patients involved in our clinical trials are generally in the hospital setting and the decision to participate can be made by the caregiver or doctor. Accordingly, seeking consent for patient participation may become difficult when the family and/or the patient may not be available to consider participation in a clinical trial and the providers/investigators seeking the consent often have no established relationship with the family or patient. The challenges of obtaining consent for patient participation have increased during the COVID-19 pandemic as hospitals have imposed restrictions on visitation by friends or family members who may be able to provide consent on behalf of patients. The COVID-19 pandemic may make patients less willing to seek medical attention or return for follow-up visits post-treatment. In addition, some of our competitors have ongoing clinical trials to treat the same indications as our product candidates, and patients who would otherwise be eligible for our clinical trials may instead enroll in clinical trials of our competitors. If we are not successful at enrolling patients in one clinical trial, it may affect when we are able to initiate our next clinical trial, which could result in significant delays in our efforts to pursue regulatory approval of and commercialize our product candidates. Patient enrollment is affected by other factors including:

Our inability to enroll a sufficient number of patients for clinical trials would result in significant delays and could require us to abandon one or more clinical trials altogether. Enrollment delays in these clinical trials may result in increased development costs for our product candidates, which would reduce the capital we have available to support our current and future product candidates and may result in our need to raise additional capital earlier than planned and could cause the value of our common stock to decline and limit our ability to obtain additional financing.

Our product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial potential or result in significant negative consequences following any potential marketing approval.

During the conduct of clinical trials, patients report changes in their health, including illnesses, injuries and discomforts (generally referred to as adverse events), to their doctor. We are required to report adverse events to the FDA and other regulatory authorities. Often, it is not possible to determine whether the product candidate being studied caused these conditions. Regulatory authorities may draw different conclusions or require additional testing to confirm

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or refute these observations, if they occur. In addition, it is possible that as we test our product candidates in larger, longer and more extensive clinical programs, or as use of these product candidates becomes more widespread if they receive regulatory approval, illnesses, injuries, discomforts and other adverse events that were observed in earlier trials, as well as conditions that did not occur or went undetected in previous trials, will be reported by subjects. Many times, side effects are only detectable after investigational drugs are tested in large-scale, Phase 3 clinical trials or, in some cases, after they are made available to patients on a commercial scale after approval. If additional clinical experience indicates that any of our current product candidates or any future product candidates of ours, has side effects or causes serious or life-threatening side effects, the development of the product candidate may fail or be delayed, or, if the product candidate has received regulatory approval, such approval may be revoked, which would harm our business, prospects, operating results and financial condition.

Moreover, if we elect, or are required, to delay, suspend or terminate any clinical trial of our product candidates, the commercial prospects of our product candidates may be harmed and our ability to generate revenue through their sale may be delayed or eliminated. Any of these occurrences may significantly harm our business, financial condition and prospects.

Additionally, if any of our product candidates receive marketing approval, regulatory authorities may require the addition of labeling statements, such as a “black box” warning or a contraindication, or the adoption of a REMS program to ensure that the benefits outweigh its risks, which may include, among other things, a medication guide outlining the risks of the drug for distribution to patients and a communication plan to health care practitioners, and/or significant restrictions on distribution or use of the drug. Furthermore, if we or others later identify undesirable side effects caused by our product candidates, several potentially significant negative consequences could result, including:

Any of these events could prevent us from achieving or maintaining market acceptance of the affected product candidate, if approved, or could substantially increase commercialization costs and expenses, which could delay or prevent us from generating revenue from the sale of our products and harm our business and results of operations.

We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product candidates or indications that may be more profitable or have a greater likelihood of success.

Because we have limited financial and management resources, we focus on research programs and product candidates that we identify for specific indications. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial drugs or profitable market opportunities. Our spending on current and future research and development programs and product candidates for specific indications may not yield any commercially viable products. If we do not accurately evaluate the commercial potential or target market

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for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

Interim “top-line” and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may announce interim top-line or preliminary data from our clinical trials. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and/or more patient data become available. Preliminary or top-line data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, interim and preliminary data should be viewed with caution until the final data are available. Differences between preliminary or interim data and final data could significantly harm our business prospects and may cause the trading price of our common stock to fluctuate significantly.

Two of our product candidates are β-lactamase inhibitors developed in combination with approved β-lactam antibiotics. If the FDA, the EMA or a comparable regulatory authority revokes the approval of one or both of β-lactam antibiotics, we may be unable to obtain approval for our product candidates.

Two of our product candidates inhibit one of the most prevalent forms of bacterial resistance, β-lactamase enzymes, so-named because of their ability to inactivate β-lactam antibiotics, one of the most commonly used classes of antibiotics. By blocking this resistance mechanism, these product candidates, when administered in combination with β-lactam antibiotics, are designed to restore the efficacy of those antibiotics. Durlobactam is a novel IV, broad-spectrum BLI that we are developing in combination with sulbactam, an IV β-lactam antibiotic, for the treatment of a variety of serious multidrug-resistant infections caused by Acinetobacter. ETX0282 is a novel, oral BLI that we are developing in combination with cefpodoxime, an oral β-lactam antibiotic, for the treatment of cUTIs, including those caused by Enterobacteriaceae.

Sulbactam and cefpodoxime are both FDA approved antibiotics. However, we did not develop or obtain marketing approval for, nor do we manufacture or sell, sulbactam or cefpodoxime or any other currently approved drug that we may study in combination with our product candidates. If the FDA, the EMA or a comparable regulatory authority revokes the approval of the drug or drugs in combination with which we determine to develop our product candidates, we may not be able to market our product candidates in such jurisdictions.

Furthermore, if safety or efficacy issues arise with any of these drugs, we could experience significant regulatory delays, and the FDA, the EMA or a comparable regulatory authority may require us to redesign or terminate the applicable clinical trials. In addition, if manufacturing or other issues result in a shortage of supply of the drugs with which we determine to combine with our product candidates, we may not be able to complete their clinical development on our current timeline or at all.

Even if our product candidates were to receive marketing approval or be commercialized for use in combination with other existing drugs, we would continue to be subject to the risks that the FDA, the EMA or a comparable regulatory authority could revoke approval of the drug used in combination with our product candidates or that safety, efficacy, manufacturing or supply issues could arise with these existing drugs.

Demand for our product candidates, if approved, will depend in part on continued resistance to empirically used broad-spectrum antibiotics and continued use of pathogen identification and resistance profiling.

Each of our product candidates, is aimed at treating antibiotic resistant gram-negative bacteria of a specific genus and/or species, such as Acinetobacter baumannii, Pseudomonas aeruginosa or certain strains of Enterobacteriaceae. Typically, when a patient presents with an infection and the bacteria causing the infection is not known or only suspected, a broad-spectrum antibiotic is administered as a first-line empiric treatment pending tests to identify the bacterial pathogen causing the infection and resistance profile. Our product candidates are being developed

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for use following the identification of the bacterial pathogen and if the resistance profile of the bacterial pathogen suggests that the first-line broad-spectrum antibiotic is not likely to be effective. Our product candidates are designed to treat specific antibiotic-resistant bacteria where broad-spectrum antibiotics are typically not effective due to the development of antibiotic resistance. However, in those cases when empiric treatment with a broad-spectrum antibiotic has been effective, or in other words the bacteria remain susceptible to existing antibiotics, there would not be a need for treatment of drug-resistant bacteria with our product candidates. If the bacteria we target become less resistant to existing broad-spectrum antibiotics, or if new broad-spectrum antibiotics are developed that are equally effective against the specific bacteria we target, then the potential demand for our product candidates could be diminished.

In addition, while pathogen identification and resistance profiling are common tests that have been employed for decades and are standard practice in hospital microbiology laboratories, and as more recently developed and approved rapid diagnostic technologies have demonstrated utility to guide the appropriate use of antibiotics, both these approaches can be costly and/or time consuming. If these tests do not remain standard procedure and available for clinicians, for example because their coverage and reimbursement status by third-party payors is reduced or eliminated, this could also limit the potential demand for our product candidates.

Risks Related to Our Dependence on Third Parties

We rely on third parties to conduct the clinical trials for our product candidates, and those third parties may not perform satisfactorily, including failing to meet deadlines for the completion of such trials or failing to comply with applicable regulatory requirements.

We have engaged contract research organizations, or CROs, to conduct our ongoing and planned clinical trials. We also expect to engage CROs for any of our other product candidates that may progress to clinical development. We expect to rely on CROs, as well as other third parties, such as clinical data management organizations, medical institutions and clinical investigators, to conduct those clinical trials. Agreements with such third parties might terminate for a variety of reasons, including a failure to perform by the third parties. If we need to enter into alternative arrangements, our product development activities would be delayed.

Our reliance on these third parties for research and development activities will reduce our control over these activities but will not relieve us of our responsibilities. For example, we will remain responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trial. Moreover, the FDA requires us to comply with regulatory standards, commonly referred to as good clinical practices, or GCPs, for conducting, recording and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. Similar regulatory requirements apply outside the United States, including the International Council for Harmonisation of Technical Requirements for the Registration of Pharmaceuticals for Human Use, or ICH.

We are also required to register certain ongoing clinical trials and post the results of certain completed clinical trials on government-sponsored, publicly accessible databases, such as, ClinicalTrials.gov, within specified timeframes. Failure to do so by us or third parties can result in FDA refusal to approve applications based on the clinical data, enforcement actions, adverse publicity and civil and criminal sanctions.

Furthermore, these third parties may also have relationships with other entities, some of which may be our competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or conduct our clinical trials in accordance with regulatory requirements or our stated protocols, we will not be able to obtain, or may be delayed in obtaining, marketing approvals for our product candidates and will not be able to, or may be delayed in our efforts to, successfully commercialize our product candidates.

In addition, principal investigators for our clinical trials may serve as scientific advisors or consultants to us from time to time and may receive cash or equity compensation in connection with such services. If these relationships and any related compensation result in perceived or actual conflicts of interest, or the FDA concludes that the financial relationship may have affected the results of the trial, the integrity of the data generated at the applicable clinical trial site may be questioned and the utility of the clinical trial itself may be jeopardized, which could result in the delay or

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rejection by the FDA of any NDA we submit. Any such delay or rejection could prevent us from commercializing our product candidates.

We also expect to rely on other third parties to store and distribute product supplies for our clinical trials. Any performance failure or regulatory noncompliance on the part of our distributors could delay clinical development or marketing approval of our product candidates or commercialization of our products, resulting in additional losses and depriving us of potential product revenue.

We rely on collaborations with third parties for the development of our product candidates, and we may seek additional collaborations in the future. If those collaborations are not successful, we may not be able to capitalize on the market potential of these product candidates.

We have limited capabilities for drug development and do not yet have any capabilities for sales, marketing or distribution. Additionally, our product development programs and the commercialization of our product candidates will require substantial additional cash to fund expenses. As a result of these factors, we are, and expect to continue to be, dependent on collaborations relating to the development and commercialization of our existing and future product candidates. We currently have a collaborative relationship with Zai Lab to develop durlobactam and SUL-DUR in the Asia-Pacific region and with GARDP to develop zoliflodacin in a Phase 3 registration trial in uncomplicated gonorrhea. We have had and will continue to have discussions on potential partnering opportunities with various pharmaceutical companies. In addition, we may seek third-party collaborators for the development and commercialization of our product candidates, particularly for the commercialization of our product candidates either within or outside the United States. Our likely collaborators for any collaboration arrangements include large and mid-size pharmaceutical companies, regional and national pharmaceutical companies and biotechnology companies and we may face significant competition in seeking appropriate collaborators. If we fail to enter into or maintain collaborations on reasonable terms or at all, our ability to develop our existing or future product candidates could be delayed, the commercial potential of our products could change, and our costs of development and commercialization could increase. If we enter into any future collaboration arrangements with any third parties, we will likely have limited control over the amount and timing of resources that our collaborators dedicate to the development or commercialization of our product candidates. Our ability to generate revenues from these arrangements will depend on our collaborators’ abilities to successfully perform the functions assigned to them in these arrangements.

Our collaborations with Zai Lab, NIAID and GARDP and any future collaborations we might enter into may pose a number of risks, including:

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Collaboration agreements may not lead to development or commercialization of product candidates in the most efficient manner or at all. If a present or future collaborator of ours were to be involved in a business combination, the continued pursuit and emphasis on our drug development or commercialization program could be delayed, diminished or terminated.

The failure of Zai Lab or GARDP to adequately perform their obligations and responsibilities in connection with the regulatory submissions for the approval of SUL-DUR or the conduct of the Phase 3 registration trial of zoliflodacin, respectively, could harm our business because we may not obtain regulatory approval for SUL-DUR or zoliflodacin in a timely manner, or at all.

We have entered into a license and collaboration agreement with Zai Lab, pursuant to which they managed the portion of our Phase 3 registration trial of SUL-DUR for Acinetobacter infections conducted in China and are responsible for all interactions with regulatory authorities within their territory, including China. We have also entered into an arrangement with GARDP pursuant to which it is conducting the Phase 3 registration trial of zoliflodacin in patients with uncomplicated gonorrhea. Under our arrangement with Zai Lab, Zai Lab funded most of our clinical trial costs in China for SUL-DUR, including all costs for our Phase 3 registration trial for Acinetobacter infections. Under our agreement with GARDP, GARDP will fund all the Phase 3 development costs for zoliflodacin, including costs of the manufacture and supply of the product candidate, and will take the lead in Phase 3 clinical development activities. While we continue to provide operational and logistical support for the Phase 3 registration trials, we have limited control of the activities of our collaborators. We cannot control whether our collaborators will devote sufficient time and resources to the Phase 3 registration trials or subsequent regulatory interactions, or if they will comply with applicable regulations and other requirements in jurisdictions where they operate. If either Zai Lab or GARDP does not successfully carry out its obligations and responsibilities or meet expected deadlines, or if the quality or accuracy of the clinical data either obtains is compromised due to the failure to adhere to clinical protocols, regulatory requirements or for other reasons, the Phase 3 registration trial of zoliflodacin may be extended, delayed or terminated, and we may not be able to obtain regulatory approval for, or successfully commercialize, either SUL-DUR or zoliflodacin. As a result, our results of

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operations and the commercial prospects for SUL-DUR or zoliflodacin would be harmed, our costs could increase and our ability to generate revenues could be delayed.

Although Zai Lab and GARDP are each responsible for conducting specified Phase 3 registration trial activities, we are responsible for ensuring that each of our clinical trials is conducted in accordance with the applicable protocol and legal, regulatory and scientific standards, and our reliance on our collaborators does not relieve us of our regulatory responsibilities. We are required to comply with GCP for any product candidate of ours in clinical development. Regulatory authorities enforce GCP through periodic inspections of trial sponsors, principal investigators and clinical trial sites. If we fail to comply with applicable GCP, the clinical data generated in our trials may be deemed unreliable and the FDA or foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials comply with GCP requirements. In addition, we must conduct our clinical trials with drug product manufactured under current good manufacturing practices, or cGMP, requirements. Failure to comply with any of these regulations may require us to repeat preclinical studies and clinical trials, which would delay the regulatory approval process.

Our reliance on third parties to manufacture our product candidates increases the risk that we will not have sufficient quantities of our product candidates or products or such quantities at an acceptable cost, which could delay, prevent or impair our development or commercialization efforts.

We do not own or operate manufacturing facilities to produce clinical or commercial supplies of the product candidates that we are developing or evaluating. We have limited personnel with experience in drug manufacturing and lack the resources and the capabilities to manufacture any of our product candidates on a clinical or commercial scale. We currently rely on third parties for supply of our product candidates, and our strategy is to outsource all manufacturing of our product candidates and approved products, if any, to third parties.

To conduct clinical trials of our product candidates, we will need to identify suitable manufacturers with the capabilities to manufacture our compounds in large quantities in a manner consistent with existing regulations. Our third-party manufacturers may be unable to successfully increase the manufacturing capacity for any of our product candidates in a timely or cost-effective manner, or at all. In addition, quality issues may arise during scale-up activities and at any other time. If our manufacturers are unable to successfully scale up the manufacture of our product candidates in sufficient quality and quantity, the development, testing and clinical trials of that product candidate may be delayed, or infeasible, and regulatory approval or commercial launch of that product candidate may be delayed or not obtained, which could significantly harm our business.

In addition, we plan to develop certain product candidates for use as a fixed-dose combination therapy. If manufacturing or other issues result in a supply shortage of sulbactam, cefpodoxime or any other currently approved drug that we may study in combination with durlobactam, ETX0282 or any of our future product candidates, we may not be able to complete clinical development of our product candidates on our current timeline or at all.

We do not currently have any agreements with third-party manufacturers for the long-term commercial supply of any of our product candidates. In the future, we may be unable to enter into agreements with third-party manufacturers for commercial supplies of our product candidates or may be unable to do so on acceptable terms.

Even if we can establish and maintain arrangements with third-party manufacturers, reliance on third-party manufacturers entails risks, including:

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Third-party manufacturers may not be able to comply with cGMP regulations or similar regulatory requirements outside the United States. Our failure, or the failure of our third-party manufacturers, to comply with applicable regulations could result in sanctions being imposed on us, including fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates or products, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect supplies of our product candidates.

Our product candidates and any products that we may develop may compete with other product candidates and products for access to manufacturing facilities. There are a limited number of manufacturers that operate under cGMP regulations and that might be capable of manufacturing for us. Furthermore, we intend to develop certain product candidates as a fixed-dose combination with β-lactams and only a limited number of cGMP manufacturers are capable of handling β-lactam antibiotics.

If the third parties that we engage to supply any materials or manufacture product for our preclinical tests and clinical trials should cease to continue to do so for any reason, we likely would experience delays in advancing these trials while we identify and qualify replacement suppliers, and we may be unable to obtain replacement supplies on terms that are favorable to us. In addition, if we are not able to obtain adequate supplies of our product candidates or the substances used to manufacture them or any of the approved drugs we use in our combination trials, it will be more difficult for us to develop our product candidates and compete effectively.

Our current and anticipated future dependence upon others for the manufacture of our product candidates may adversely affect our future profit margins and our ability to develop product candidates and commercialize any products that receive marketing approval on a timely and competitive basis.

We may not be able to win government or non-profit contracts or grants to fund our product development activities.

Historically, we have relied in part on funding from contracts or grants from government agencies and non-profit entities and it is part of our strategy to continue to do so. Such contracts or grants can be highly attractive because they provide capital to fund the on-going development of our product candidates without diluting our stockholders. However, there is often significant competition for these contracts or grants. Entities offering contracts or grants may have requirements to apply for or to otherwise be eligible to receive certain contracts or grants that our competitors may be able to satisfy that we cannot. In addition, such entities may make arbitrary decisions as to whether to offer contracts or make grants, to whom the contracts or grants will be awarded and the size of the contracts or grants to each awardee. Even if we can satisfy the award requirements, there is no guarantee that we will be selected to receive any contract or grant. If we are not successful in achieving this form of funding for our clinical trials, we will need to seek alternative means of funding which may not be available to the same extent, if at all.

Our reliance on government funding for certain of our programs adds uncertainty to our research, development and commercialization efforts with respect to those programs and may impose requirements that increase the costs of the research, development and commercialization of product candidates developed under those government-funded programs.

Aspects of our development programs are currently being supported, in part, with funding from the NIH, NIAID, CARB-X and the DOD. Contracts and grants awarded by the U.S. government, its agencies and its partners, including our awards from the NIH, NIAID, CARB-X, and the DOD, include provisions that reflect the government’s

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substantial rights and remedies, many of which are not typically found in commercial contracts, including powers of the government to:

We may not have the right to prohibit the U.S. government from using certain technologies developed by us, and we may not be able to prohibit third-party companies, including our competitors, from using those technologies in providing products and services to the U.S. government. The U.S. government generally takes the position that it has the right to royalty-free use of technologies that are developed under U.S. government contracts.

In addition, government contracts and grants, and subcontracts and subawards awarded in the performance of those contracts and grants, normally contain additional requirements that may increase our costs of doing business, reduce our profits, and expose us to liability for failure to comply with these terms and conditions. These requirements include, for example:

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As an organization, we are relatively new to government contracting and new to the regulatory compliance obligations that such contracting entails. If we fail to maintain compliance with those obligations, we may be subject to potential liability and termination of our contracts.

As a U.S. government contractor, we are subject to financial audits and other reviews by the U.S. government of our costs and performance on their contracts, as well as our accounting and general business practices related to these contracts. Based on the results of its audits, the government may adjust our contract-related costs and fees, including allocated indirect costs.

Risks Related to the Commercialization of Our Product Candidates

If we are unable to establish sales, marketing, market access, manufacturing and distribution capabilities for our product candidates, or enter into sales, marketing and distribution agreements with third parties, we may not be successful in commercializing our product candidates, if and when they are approved.

We do not have a sales, marketing, or market access infrastructure and have no experience in the sale, marketing or distribution of pharmaceutical products. To achieve commercial success for any product candidate for which we may obtain marketing approval, we will need to establish a sales, marketing and market access organization or enter into collaboration, distribution and other sales, marketing and/or market access arrangements with one or more third parties to commercialize our product candidates. In the United States, we are evaluating whether to build our own commercial organization to target sites of care with the greatest incidence of serious and life-threatening multidrug-resistant infections and recruit experienced sales, marketing, market access and distribution professionals, leverage the experience and capabilities of an established commercial organization, or engage a third party who will establish select commercial capabilities on our behalf. The development of sales, marketing, market access and distribution capabilities will require substantial resources, will be time-consuming and could delay any product launch. We are considering working with multi-national pharmaceutical companies or experienced regional healthcare companies to leverage their commercialization capabilities to commercialize any product candidate for which we may obtain regulatory approval either within and/or outside of the United States.

If the commercial launch of a product candidate for which we, or a third party, recruit a sales force and establish marketing, market access and distribution capabilities is delayed or does not occur for any reason, we would have prematurely or unnecessarily incurred these commercialization costs. This may be costly, and our investment would be lost if we cannot retain or reposition our sales, marketing and market access personnel. In addition, we may not be able to hire a sales force in the United States that is sufficient in size or has adequate expertise to target the sites of care that we intend to target. If we are unable to establish a sales force, marketing, market access and distribution capabilities, our operating results may be adversely affected.

Factors that may inhibit our or our collaborators efforts to commercialize our drugs include:

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If we are unable to establish our own sales, marketing, market access and distribution capabilities in the United States and, instead, enter into arrangements with third parties to perform these services, our revenues from these products and our profitability, if any, could potentially be lower than if we were to sell, market and distribute any product candidates that we develop ourselves. We intend to work with multi-national pharmaceutical companies or experienced healthcare companies to assist with the commercialization outside the United States of any of our product candidates that receive regulatory approval. In addition, we may not be successful in entering into arrangements with third parties to sell, market and distribute our product candidates or may be unable to do so on terms that are favorable to us. We likely will have limited control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market our product candidates effectively. If we do not establish sales, marketing, market access and distribution capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our product candidates.

Even if any of our product candidates receives marketing approval, it may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success.

Even if we obtain approvals from the FDA, the EMA or other comparable regulatory agencies and can initiate commercialization of a product candidate we develop, the product candidate may not achieve market acceptance among physicians, patients, hospitals, including pharmacy directors, and third-party payors and, ultimately, may not be commercially successful. The degree of market acceptance of our product candidates, if approved for commercial sale, will depend on several factors, including:

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Any failure by any of our product candidates that obtains regulatory approval to achieve market acceptance or commercial success would have a material adverse effect on our business prospects.

We face substantial competition, which may result in others discovering, developing, or commercializing products before or more successfully than we do.

The development and commercialization of new drug products is highly competitive. We face competition from major multi-national pharmaceutical companies, biotechnology companies, specialty pharmaceutical companies and generic drug companies with respect to our current and future product candidates. There are several large pharmaceutical and biotechnology companies that currently market and sell products or are pursuing the development of product candidates for the treatment of drug-resistant infections. Potential competitors also include academic institutions, government agencies and other public and private research organizations. Our competitors may succeed in developing, acquiring or licensing technologies and drug products that are more effective, more effectively marketed and sold or less costly than our product candidates, which could render our product candidates non-competitive and obsolete.

We are initially developing SUL-DUR for the treatment of pneumonia and bloodstream infections caused by multidrug-resistant Acinetobacter. Due to rising resistance rates, standard-of-care treatment for multidrug-resistant Acinetobacter often includes a combination of several last-line treatment options, including carbapenems, tetracyclines and polymyxins, all generically available agents. As of the date of this report, we are not aware of any marketed antibiotic that is indicated for the treatment of multidrug-resistant Acinetobacter infections; however, we are aware of other potentially competitive products that have shown in vitro activity against some strains of Acinetobacter.

We are initially developing zoliflodacin for the treatment of uncomplicated gonorrhea due to N. gonorrhoeae infections, including multidrug-resistant strains. Gonorrhea is commonly treated with the combination therapy of intramuscular ceftriaxone injection and oral azithromycin, both generically available agents. Additional generic cephalosporins and fluoroquinolones are also prescribed, but not recommend as primary treatment options given current resistance rates. Gepotidacin, currently under development for a variety of infections by GlaxoSmithKline plc, is the only potentially competitive product candidate in late-phase clinical development that we are aware of that is addressing gonorrhea.

We have initially developed ETX0282CPDP for the treatment of cUTIs, including those caused by multidrug-resistant Enterobacteriaceae. There are a variety of generically available antibiotic classes available for the treatment of such infections, including cephalosporins, carbapenems and fluoroquinolones. Additionally, there are several IV approved branded agents targeting multidrug-resistant cUTIs. We are aware of additional potentially competitive oral product candidates that may address a limited breadth of multidrug-resistant Gram-negative pathogens.

If our competitors obtain marketing approval from the FDA, the EMA or other comparable regulatory authorities for their product candidates more rapidly than we do, it could result in our competitors establishing a strong market position before we are able to enter the market.

Many of our competitors have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do as an organization. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller and other early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These third parties compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

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Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any product candidates that we may develop. Our competitors also may obtain approval from the FDA, the EMA or other comparable regulatory agencies for their product candidates more rapidly than we may obtain approval for ours, which could result in product approval delays if a competitor obtains market exclusivity from the FDA or the EMA, or our competitors establishing a strong market position before we are able to enter the market. In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic drugs. Additional drugs may become available on a generic basis over the coming years. If our product candidates achieve marketing approval, we expect that they will be priced at a significant premium over competitive generic drugs.

Coverage and adequate reimbursement may not be available for our current or any future product candidates, which could make it difficult for us to sell profitably, if approved.

Market acceptance and sales of any product candidates that we or our collaborators commercialize will depend in part on the extent to which reimbursement for these drugs and related treatments will be available from third-party payors, including government health care programs (such as Medicare and Medicaid), government health administration authorities, managed care organizations and other private health insurers. Third-party payors decide which therapies they will pay for and establish reimbursement levels. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own coverage and reimbursement policies. However, decisions regarding the extent of coverage and amount of reimbursement to be provided for any product candidates that we develop will be made on a payor-by-payor basis. One payor’s determination to provide coverage for a drug does not assure that other payors will also provide coverage and adequate reimbursement for the drug. Additionally, a third-party payor’s decision to provide coverage for a therapy does not imply that an adequate reimbursement rate will be approved. Each payor determines whether it will provide coverage for a therapy, what amount it will pay the manufacturer for the therapy, and on what tier of its list of covered drugs, or formulary, it will be placed. The position on a payor’s formulary, generally determines the co-payment that a patient will need to make to obtain the therapy and can strongly influence the adoption of such therapy by patients and physicians. Patients who are prescribed treatments for their conditions and providers prescribing such services generally rely on third-party payors to reimburse all or part of the associated healthcare costs. Patients are unlikely to use our drugs, and providers are unlikely to prescribe our drugs, unless coverage is provided, and reimbursement is adequate to cover a significant portion of the cost of our drugs and their administration.

A primary trend in the United States healthcare industry and elsewhere is cost containment. Third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. We cannot be sure that coverage and reimbursement will be available for any drug that we commercialize and, if reimbursement is available, what the level of reimbursement will be. Inadequate coverage and reimbursement may impact the demand for, or the price of, any drug for which we obtain marketing approval. If coverage and adequate reimbursement are not available, or are available only to limited levels, we may not be able to successfully commercialize our current and any future product candidates that we develop.

Product liability lawsuits against us could cause us to incur substantial liabilities and to limit commercialization of any products that we may develop.

We face an inherent risk of product liability exposure related to the testing of our product candidates in human clinical trials and will face an even greater risk if we commercially sell any drugs that we may develop. If we cannot successfully defend ourselves against claims that our product candidates or products caused injuries, we will incur substantial liabilities. Regardless of merit or eventual outcome, liability claims may result in:

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We currently hold $10.0 million in product liability insurance coverage in the aggregate, with a per incident limit of $10.0 million, which may not be adequate to cover all liabilities that we may incur. We may need to increase our insurance coverage as we expand our clinical trials or if we commence commercialization of our product candidates. Insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a reasonable cost or in an amount adequate to satisfy any liability that may arise.

There are a variety of risks associated with marketing our product candidates internationally, which could affect our business.

We or our collaborators may seek regulatory approval for our product candidates outside of the United States and, accordingly, we expect that we will be subject to additional risks related to operating in foreign countries if we obtain the necessary approvals, including:

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These and other risks associated with our international operations may compromise our ability to achieve or maintain profitability.

Risks Related to Our Business and Managing Our Growth

Our future success depends on our ability to retain key executives and to attract, retain and motivate qualified personnel.

We are highly dependent on the management, research and development, clinical, financial and business development expertise of Manoussos Perros, Ph.D., our chief executive officer, David Altarac, M.D., our chief medical officer, John Mueller, Ph.D., our chief development officer, Ruben Tommasi, Ph.D., our chief scientific officer, Matt Ronsheim, Ph.D., our chief pharmaceutical sciences and manufacturing officer, and Anna Diaz Triola, our chief commercial officer, as well as the other members of our scientific and clinical teams. Although we have employment agreements with our executive officers, each of them may nevertheless terminate their employment with us at any time. We do not maintain “key person” insurance for any of our executives or employees.

Recruiting and retaining qualified scientific and clinical personnel and, if we progress the development of any of our product candidates, commercialization, manufacturing and sales and marketing personnel, will be critical to our success. The loss of the services of our executive officers or other key employees could impede the achievement of our research, development and commercialization objectives and seriously harm our ability to successfully implement our business strategy. Furthermore, replacing executive officers and key employees may be difficult and may take an extended period of time because of the limited number of individuals in our industry with the breadth of skills and experience required to successfully develop, gain regulatory approval of and commercialize our product candidates. Competition to hire from this limited pool is intense, and we may be unable to hire, train, retain or motivate these key personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for similar personnel. We also experience competition for the hiring of scientific and clinical personnel from universities and research institutions. In addition, we rely on consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and development and commercialization strategy. Our consultants and advisors may have commitments under consulting or advisory contracts with other entities that may limit their availability to us. If we are unable to continue to attract and retain high-quality personnel, our ability to pursue our growth strategy will be limited.

We expect to expand our development and regulatory capabilities and potentially implement sales, marketing and distribution capabilities, and as a result, we may encounter difficulties in managing our growth, which could disrupt our operations.

As of December 31, 2021, we had 51 full-time employees. As the clinical development of our product candidates progresses, we also expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of quality and regulatory and medical affairs and, if any of our product candidates receives marketing approval, sales, marketing, product supply chain as well as G&A functions including IT and finance. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, potentially expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or

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recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

Risks Related to Our Intellectual Property

If we are unable to obtain and maintain patent protection for our technology and product candidates, or if the scope of the patent protection obtained is not sufficiently broad, our competitors could develop and commercialize technology and drugs similar or identical to ours, and our ability to successfully commercialize our technology and product candidates may be adversely affected.

Our success depends in large part on our ability to obtain and maintain patent protection in the United States and other countries with respect to our product candidates. We seek to protect our proprietary position by filing patent applications in the United States and abroad related to our technology and product candidates. If we do not adequately protect our intellectual property, competitors may be able to use our technologies and erode or negate any competitive advantage that we may have, which could harm our business and ability to achieve profitability. To protect our proprietary positions, we file patent applications in the United States and abroad related to our novel technologies and product candidates that are important to our business.

The patent application and prosecution process are expensive and time-consuming. We and our current licensees, or any future licensors and licensees may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. We or our current licensees, or any future licensors or licensees may also fail to identify patentable aspects of our research and development before it is too late to obtain patent protection.

Therefore, these and any of our patents and applications may not be prosecuted and enforced in a manner consistent with the best interests of our business. It is possible that defects of form in the preparation or filing of our patents or patent applications may exist, or may arise in the future, such as with respect to proper priority claims, inventorship, claim scope or patent term adjustments. If our current licensees, or any future licensors or licensees, are not fully cooperative or disagree with us as to the prosecution, maintenance or enforcement of any patent rights, such patent rights could be compromised, and we might not be able to prevent third parties from making, using and selling competing products. If there are material defects in the form or preparation of our patents or patent applications, such patents or applications may be invalid and/or unenforceable. Moreover, our competitors may independently develop equivalent knowledge, methods and know-how. Any of these outcomes could impair our ability to prevent competition from third parties.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain. Changes in either the patent laws or interpretation of the patent laws in the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection. In addition, the laws of foreign countries may not protect our rights to the same extent as the laws of the United States. No consistent policy regarding the breadth of claims allowed in biotechnology and pharmaceutical patents has emerged to date in the United States or in many foreign jurisdictions. For example, European patent law currently restricts the patentability of methods of treatment of the human body more than United States law does. In addition, the determination of patent rights with respect to pharmaceutical compounds and technologies commonly involves complex legal and factual questions, which has in recent years been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our patent rights are highly uncertain. Furthermore, recent changes in patent laws in the United States, including the America Invents Act of 2011, may affect the scope, strength and enforceability of our patent rights or the nature of proceedings that may be brought by us related to our patent rights.

We may not be aware of all third-party intellectual property rights potentially relating to our current and future our product candidates. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing, or in some cases not at all. Therefore, we cannot be certain that we were the first to make the inventions claimed in our patents or pending patent applications, or that we were the first to file for patent protection of such inventions. Similarly,

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should we own any patents or patent applications in the future, we may not be certain that we were the first to file for patent protection for the inventions claimed in such patents or patent applications. As a result, the issuance, scope, validity and commercial value of our patent rights cannot be predicted with any certainty. Moreover, we may be subject to a third-party pre-issuance submission of prior art to the U.S. Patent and Trademark Office, or USPTO, or become involved in derivation, ex-parte reexamination, or inter partes review proceedings in the USPTO or similar proceedings elsewhere, challenging our patent rights or the patent rights of others. An adverse determination in any such submission, proceeding or litigation could reduce the scope of, or invalidate, our patent rights, allow third parties to commercialize our technology or product candidates and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize products without infringing third-party patent rights. If the breadth or strength of protection provided by our patents and patent applications is threatened, regardless of the outcome, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

Our pending and future patent applications may not result in patents being issued that protect our technology or product candidates, in whole or in part, or which effectively prevent others from commercializing competitive technologies and products. Even if our patent applications issue as patents, they may not issue in a form that will provide us with any meaningful protection against competing products or processes sufficient to achieve our business objectives, prevent competitors from competing with us or otherwise provide us with any competitive advantage. Our competitors may be able to circumvent our owned or licensed patents by developing similar or alternative technologies or products in a non-infringing manner. Our competitors may seek to market generic versions of any approved products by submitting abbreviated new drug applications to the FDA in which they claim that patents owned or licensed by us are invalid, unenforceable and/or not infringed. Alternatively, our competitors may seek approval to market their own products similar to or otherwise competitive with our products. In these circumstances, we may need to defend and/or assert our patents, including by filing lawsuits alleging patent infringement. In any of these types of proceedings, a court or other agency with jurisdiction may find our patents invalid and/or unenforceable.

The issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, and our owned and licensed patents may be challenged in the courts or patent offices in the United States and abroad. Such challenges may result in loss of exclusivity or freedom to operate, a patent being held unenforceable, and/or in one or more or in patent claims being narrowed or invalidated or held unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar or identical technology and products or limit the duration of the patent protection of our technology and products.

Patent terms may be inadequate to protect our competitive position on our product candidates for an adequate amount of time.

Patents have a limited lifespan. In the U.S., if all maintenance fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest filing date of a non-provisional application to which the patent claims priority. Various extensions may be available, but the life of a patent, and the protection it affords, is limited. Even if patents covering our product candidates are obtained, once the patent life has expired for a product candidate, we may be open to competition from competitive medications, including generic medications. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such product candidates might expire before or shortly after such product candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing product candidates similar or identical to ours.

In addition, given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. Depending upon the timing, duration and conditions of any FDA marketing approval of our product candidates, one or more of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Amendments, and similar legislation in the European Union, as discussed above. As a result, our revenue from applicable products could be reduced. Further, if this occurs, our competitors may take advantage of our investment in development and trials by referencing our clinical and preclinical data and launch their product earlier than might otherwise be the case, and our competitive position, business, financial condition, results of operations, and prospects could be materially harmed.

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We may become involved in lawsuits to protect or enforce our patents or other intellectual property, which could be expensive, time-consuming and unsuccessful.

Competitors and other third parties may infringe our issued patents, trademarks, copyrights or other intellectual property. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time-consuming and divert the time and attention of our management and scientific personnel. Any claims we assert against perceived infringers could provoke these parties to assert counterclaims against us alleging that we infringe their patents, trademarks, copyrights or other intellectual property. In addition, in a patent infringement proceeding, there is a risk that a court will decide that a patent of ours is invalid or unenforceable or that one or more claims of a patent are invalid, in whole or in part, and that we do not have the right to stop the other party from using the invention at issue. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the USPTO, or made a misleading statement, during prosecution. There is also a risk that, even if the validity of such patents is upheld, the court will construe the patent’s claims narrowly or decide that we do not have the right to stop the other party from using the invention at issue on the basis that our patents do not cover the invention. An adverse outcome in a litigation or proceeding involving our patents could limit our ability to assert our patents against those parties or other competitors and may curtail or preclude our ability to exclude third parties from making and selling similar or competitive products. Similarly, if we assert trademark infringement claims, a court may determine that the marks we have asserted are invalid or unenforceable, or that the party against whom we have asserted trademark infringement has superior rights to the marks in question. In this case, we could ultimately be forced to cease use of such trademarks.

In any infringement litigation, any award of monetary damages we receive may not be commercially valuable. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. Moreover, there can be no assurance that we will have sufficient financial or other resources to file and pursue such infringement claims, which typically last for years before they are concluded. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources and more mature and developed intellectual property portfolios. Even if we ultimately prevail in such claims, the monetary cost of such litigation and the diversion of the attention of our management and scientific personnel could outweigh any benefit we receive because of the proceedings. Accordingly, despite our efforts, we may not be able to prevent third parties from infringing, misappropriating or successfully challenging our intellectual property rights. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a negative impact on our ability to compete in the marketplace.

Third parties may initiate legal proceedings alleging that we are infringing their intellectual property rights, the outcome of which would be uncertain and could significantly harm our business.

Our business success depends, in part, on our ability to discover, develop, manufacture, market and sell our product candidates without infringing the intellectual property and other proprietary rights of third parties. Numerous third-party U.S. and non-U.S. issued patents exist in the area of antibacterial treatment, including compounds, formulations, treatment methods and synthetic processes that may be applied towards the synthesis of antibiotics. If any of their patents cover our product candidates or technologies, we may not be free to manufacture or market our product candidates as planned.

There is a substantial amount of intellectual property litigation in the biotechnology and pharmaceutical industries, and we may become party to, or threatened with, litigation or other adversarial proceedings regarding intellectual property rights with respect to our technology or product candidates, including interference proceedings before the USPTO. Intellectual property disputes arise in several areas including with respect to patents, use of other proprietary rights and the contractual terms of license arrangements. Third parties may assert claims against us based on existing or future intellectual property rights. The outcome of intellectual property litigation is subject to uncertainties that cannot be adequately quantified in advance.

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If we are found to infringe a third-party’s intellectual property rights, we could be forced, including by court order, to cease developing, manufacturing or commercializing the infringing product candidate or product. Alternatively, we may be required to obtain a license from such third party to use the infringing technology and continue developing, manufacturing or marketing the infringing product candidate. However, we may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. In addition, we could be found liable for monetary damages, including treble damages and attorneys’ fees if we are found to have willfully infringed a patent. A finding of infringement could prevent us from commercializing our product candidates or force us to cease some of our business operations. Claims that we have misappropriated the confidential information or trade secrets of third parties could have a similar negative effect on our business.

We may need to license intellectual property from third parties, and such licenses may not be available or may not be available on commercially reasonable terms.

A third party may hold intellectual property rights, including patent rights, that are important or necessary to the development of our product candidates. It may be necessary for us to use the patented or proprietary technology of third parties to commercialize our product candidates, in which case we would be required to obtain a license from these third parties. Such a license may not be available on commercially reasonable terms, or at all, and we could be forced to accept unfavorable contractual terms. If we are unable to obtain such licenses on commercially reasonable terms, our business could be harmed.

If we are unable to obtain rights to required third-party intellectual property rights or maintain the existing intellectual property rights we have, we may be required to expend significant time and resources to redesign our technology, product candidates, or the methods for manufacturing them or to develop or license replacement technology, all of which may not be feasible on a technical or commercial basis. If we are unable to do so, we may be unable to develop or commercialize the affected technology and product candidates, which could materially harm our business, financial condition, results of operations, and prospects.

We may be subject to claims by third parties asserting that we or our employees, consultants or contractors have wrongfully used or disclosed confidential information of third parties, or we have wrongfully used or disclosed alleged trade secrets of their current or former employers, or claims asserting we have misappropriated their intellectual property or claiming ownership of what we regard as our own intellectual property.

Many of our employees were previously employed at universities or other biotechnology or pharmaceutical companies. Although we try to ensure that our employees do not use the proprietary information or know-how of third parties in their work for us, we may be subject to claims that these employees or we have inadvertently or otherwise used intellectual property, including trade secrets or other proprietary information, of any such employee’s former employer. We may also in the future be subject to claims that we have caused an employee to breach the terms of his or her non-competition or non-solicitation agreement. Litigation may be necessary to defend against these potential claims.

In addition, while it is our policy to require our employees and contractors who may be involved in the development of intellectual property to execute agreements assigning such intellectual property to us, such employees and contractors may breach the agreement and claim the developed intellectual property as their own.

Our business was founded in 2015 as a spin-out from AstraZeneca AB, or AstraZeneca. Although all patent applications are fully owned by us and were either filed by AstraZeneca with all rights fully transferred to us, or filed in our sole name, because we acquired certain of our patents from AstraZeneca, we must rely on their prior practices, regarding the assignment of such intellectual property. Our and their assignment agreements may not be self-executing or may be breached, and we may be forced to bring claims against third parties or defend claims they may bring against us, to determine the ownership of what we regard as our intellectual property.

If we fail in prosecuting or defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. A court could prohibit us from using technologies or features that are essential to our products if such technologies or features are found to incorporate or be derived from the trade secrets or

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other proprietary information of the former employers. Even if we are successful in prosecuting or defending against such claims, litigation could result in substantial costs and could be a distraction to management. In addition, any litigation or threat thereof may adversely affect our ability to hire employees or contract with independent service providers. Moreover, a loss of key personnel or their work product could hamper or prevent our ability to commercialize our products.

Any trademarks we may obtain may be infringed or successfully challenged, resulting in harm to our business.

We expect to rely on trademarks as one means to distinguish any of our product candidates that are approved for marketing from the products of our competitors. Once we select trademarks and apply to register them, our trademark applications may not be approved. Third parties may oppose our trademark applications, or otherwise challenge our use of the trademarks. If our trademarks are successfully challenged, we could be forced to rebrand our products, which could result in loss of brand recognition and could require us to devote resources to advertising and marketing new brands. Our competitors may infringe our trademarks and we may not have adequate resources to enforce our trademarks.

In addition, any proprietary name we propose to use with a product candidate in the United States must be approved by the FDA, regardless of whether we have registered it, or applied to register it, as a trademark. The FDA typically conducts a review of proposed product names, including an evaluation of the potential for confusion with other product names. If the FDA objects to any of our proposed proprietary product names, we may be required to expend significant additional resources to identify a suitable proprietary product name that would qualify under applicable trademark laws, not infringe the existing rights of third parties and be acceptable to the FDA.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patent and trademark protection for our product candidates, we also rely on trade secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive position. We seek to protect our trade secrets, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to them, such as our employees, corporate collaborators, outside scientific collaborators, contract manufacturers, consultants, advisors and other third parties prior to beginning research or disclosing proprietary information. We also enter into confidentiality and invention or patent assignment agreements with our employees and consultants. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets. Despite these efforts and the contractual provisions employed when working with third parties, the need to share trade secrets and other confidential information due to our reliance on third parties, increases the risk that such trade secrets become known by our competitors, are inadvertently incorporated into the technology of others, or are disclosed or used in violation of these agreements.

Monitoring unauthorized uses and disclosures of our intellectual property is difficult, and we do not know whether the steps we have taken to protect our intellectual property will be effective. In addition, we may not be able to obtain adequate remedies for any such breaches. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and outside the United States are less willing or unwilling to protect trade secrets.

Moreover, our competitors may independently develop knowledge, methods and know-how equivalent to our trade secrets. Competitors could purchase our products and replicate some or all the competitive advantages we derive from our development efforts for technologies on which we do not have patent protection. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them, or those to whom they communicate it, from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed.

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We may not be able to protect our intellectual property rights throughout the world.

Filing, prosecuting and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the United States could be less extensive than those in the United States. In some cases, we may not be able to obtain patent protection for certain licensed technology outside the United States. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States, even in jurisdictions where we do pursue patent protection. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, even in jurisdictions where we do pursue patent protection or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions.

Competitors may use our technologies in jurisdictions where we have not pursued and obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories where we have patent protection, but enforcement is not as strong as that in the United States. These products may compete with our product candidates and preclinical programs and our patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets and other intellectual property protection, particularly those relating to biotechnology products, which could make it difficult for us to stop the infringement of our patents, if pursued and obtained, or marketing of competing products in violation of our proprietary rights generally. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate, and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Risks Related to Regulatory Approval of Our Product Candidates and Other Legal Compliance Matters

Even if we complete the necessary preclinical studies and clinical trials, the regulatory approval process is expensive, time-consuming and uncertain and may prevent us or any future collaborators from obtaining approvals for the commercialization of some or all of our product candidates. As a result, we cannot predict when or if, and in which territories, we, or any future collaborators, will obtain marketing approval to commercialize a product candidate.

Our product candidates and the activities associated with their development and commercialization, including their design, research, testing, manufacture, safety, efficacy, quality control, recordkeeping, labeling, packaging, storage, approval, advertising, promotion, sale, distribution, import, export, and reporting of safety and other post-market information, are subject to comprehensive regulation by the FDA, the EMA and other foreign regulatory agencies. Failure to obtain marketing approval for a product candidate will prevent us or a potential collaborator from commercializing the product candidate. We have not received approval to market any of our product candidates from regulatory authorities in any jurisdiction. We have only limited experience in filing and supporting the applications necessary to gain marketing approvals and will rely on third parties to assist us in this process. Securing marketing approval requires the submission of extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. Our product candidates may not be effective, may be only moderately effective or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing approval or prevent or limit commercial use. We may not be able to successfully manufacture our products in compliance with applicable requirements such as GMPs. If any of our product candidates

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receives marketing approval, the accompanying label may limit its approved use more narrowly than we anticipate, which could limit sales of the product.

The process of obtaining marketing approvals, both in the United States and abroad, is expensive and may take many years, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. Securing marketing approval requires the submission of extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. The FDA, the EMA or other regulatory authorities may determine that our product candidates are not safe and effective, only moderately effective or have undesirable or unintended side effects, toxicities or other characteristics that preclude our obtaining marketing approval or prevent or limit commercial use. Any marketing approval we ultimately obtain may be limited or subject to restrictions or post-approval commitments that render the approved product not commercially viable.

In addition, changes in marketing approval policies during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory review for each submitted product application, may cause delays in the approval or rejection of an application. Regulatory authorities have substantial discretion in the approval process and may refuse to accept any application or may decide that our data is insufficient for approval and require additional preclinical, clinical or other studies. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate. Any marketing approval we ultimately obtain may be limited or subject to restrictions or post-approval commitments that render the approved product not commercially viable. Any marketing approval we, or any future collaborators, ultimately obtain may be limited or subject to restrictions or post-approval commitments that render the approved product not commercially viable.

If we experience delays in obtaining approval or if we fail to obtain approval of our product candidates, the commercial prospects for our product candidates may be harmed and our ability to generate revenues will be impaired.

Failure to obtain marketing approval in foreign jurisdictions would prevent our product candidates from being marketed in these territories. Any approval we are granted for our product candidates in the United States would not assure approval of our product candidates in foreign jurisdictions.

To market and sell our products in the European Union, or EU, and any other jurisdictions, we must obtain separate marketing approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among countries and can involve additional testing. The time required to obtain approval may differ substantially from that required to obtain approval from the FDA. The regulatory approval process outside the United States generally includes all the risks associated with obtaining approval from the FDA. In addition, in many countries outside the United States, it is required that the product be approved for reimbursement before the product can be approved for sale in that country. We may not obtain approvals from regulatory authorities outside the United States on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries or jurisdictions, and approval by one regulatory authority outside the United States does not ensure approval by regulatory authorities in other countries or jurisdictions or by the FDA. However, denial of approval in one jurisdiction may impact our ability to obtain approval elsewhere. We may not be able to file for marketing approvals and may not receive necessary approvals to commercialize our products in any market.

Even if we obtain marketing approvals for our product candidates, the terms of approvals and ongoing regulation of our products may limit how we or our collaborators manufacture and market our products and compliance with such requirements may involve substantial resources, which could materially impair our ability to generate revenue.

Even if marketing approval of a product candidate is granted, an approved product and its manufacturer and marketer are subject to ongoing review and extensive regulation, including the potential requirements to implement a REMS or to conduct costly post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of the product. We must also comply with requirements concerning advertising and promotion for any of our product

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candidates for which we obtain marketing approval. Promotional communications with respect to prescription drugs are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the product’s approved labeling. Thus, we will not be able to promote any products we develop for indications or uses for which they are not approved. In addition, manufacturers of approved products and those manufacturers’ facilities are required to comply with extensive FDA requirements including ensuring that quality control and manufacturing procedures conform to cGMP, which include requirements relating to quality control and quality assurance as well as the corresponding maintenance of records and documentation and reporting requirements, among other things. We and our contract manufacturers could be subject to periodic unannounced inspections by the FDA to monitor and ensure compliance with cGMP. We must also comply with FDA requirements for adverse event reporting for commercial products.

Accordingly, assuming we receive marketing approval for one or more of our product candidates, we and our contract manufacturers will continue to expend time, money and effort in all areas of regulatory compliance, including manufacturing, production, product surveillance and quality control. If we are not able to comply with post-approval regulatory requirements, we could have the marketing approvals for our products withdrawn by regulatory authorities and our ability to market any future products could be limited, which could adversely affect our ability to achieve or sustain profitability. We could also be subject to other civil or criminal penalties. Thus, the cost of compliance with post-approval regulations may have a negative effect on our operating results and financial condition.

Any product candidate for which we obtain marketing approval could be subject to post-marketing restrictions or recall or withdrawal from the market, and we may be subject to penalties if we fail to comply with regulatory requirements or if we experience unanticipated problems with our product candidates, when and if any of them are approved.

The FDA and other federal and state agencies, including the U.S. DOJ, closely regulate compliance with all requirements governing prescription drug products, including requirements pertaining to marketing and promotion of drugs in accordance with the provisions of the approved labeling and manufacturing of products in accordance with cGMP requirements. The FDA and DOJ impose stringent restrictions on manufacturers’ communications regarding off-label use and if we market our products for indications other than their approved indications, we may be subject to enforcement action for off-label marketing. Violations of such requirements may lead to investigations alleging violations of the Food, Drug and Cosmetic Act and other statutes, including the False Claims Act and other federal and state health care fraud and abuse laws as well as state consumer protection laws.

Our failure to comply with all regulatory requirements, and later discovery of previously unknown adverse events or other problems with our products, manufacturers or manufacturing processes, may yield various results, including:

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Non-compliance by us or any future collaborator with regulatory requirements regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, can also result in significant financial penalties. Similarly, failure to comply with regulatory requirements regarding the protection of personal information can also lead to significant penalties and sanctions.

Non-compliance with U.K. and EU requirements regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, also can result in significant financial penalties. Similarly, failure to comply with the U.K.’s or EU’s requirements regarding the protection of personal information can also lead to significant penalties and sanctions.

Our employees, independent contractors, principal investigators, CROs, CMOs, consultants, commercial partners and vendors may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements.

We are exposed to the risk of employee fraud or other misconduct or failure to comply with applicable regulatory requirements. Misconduct by employees and independent contractors, such as principal investigators, CROs, consultants, commercial partners and vendors, could include failures to comply with regulations of the FDA, the EMA and other comparable regulatory authorities, to provide accurate information to such regulators, to comply with manufacturing standards we have established, to comply with healthcare fraud and abuse laws, to report financial information or data accurately or to disclose unauthorized activities to us. Sales, marketing and other business arrangements in the healthcare industry are subject to extensive laws intended to prevent fraud, kickbacks, self-dealing and other abusive practices. Employee and independent contractor misconduct could also involve the improper use of individually identifiable information, including, without limitation, information obtained during clinical trials, which could result in regulatory sanctions and serious harm to our reputation. In addition, federal procurement laws impose substantial penalties for misconduct in connection with government contracts and require certain contractors to maintain a code of business ethics and conduct. It is not always possible to identify and deter employee and independent contractor misconduct, and any precautions we take to detect and prevent improper activities may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws. If any such actions are instituted against us, those actions could have a significant impact on our business, including the imposition of civil, criminal and administrative penalties, damages, monetary fines, disgorgement, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, additional reporting or oversight obligations if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with the law and curtailment or restructuring of our operations, any of which could adversely affect our ability to operate.

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Our current and future relationships with healthcare professionals, principal investigators, consultants, customers and third-party payors in the United States and elsewhere may be subject, directly or indirectly, to applicable anti-kickback, fraud and abuse, false claims, physician payment transparency, health information privacy and security and other healthcare laws and regulations, which could expose us to penalties.

Our current and future arrangements with healthcare professionals, principal investigators, consultants, customers and third-party payors may expose us to broadly applicable fraud and abuse and other healthcare laws, including, without limitation, the federal Anti-Kickback Statute and the federal False Claims Act, that may constrain the business or financial arrangements and relationships through which we research, sell, market and distribute any product candidates for which we obtain marketing approval. In addition, we may be subject to physician payment transparency laws and patient privacy and security regulation by the federal government and by the states and foreign jurisdictions in which we conduct our business. The applicable federal, state and foreign healthcare laws that may affect our ability to operate include the following:

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Further, the ACA, among other things, amended the intent requirement of the federal Anti-Kickback Statute and certain criminal statutes governing healthcare fraud. A person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it. In addition, the ACA provided that the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the False Claims Act.

Efforts to ensure that our future business arrangements with third parties will comply with applicable healthcare laws and regulations may involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, including, without limitation, damages, monetary fines, disgorgement, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, additional reporting or oversight obligations if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with the law and curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and pursue our strategy. If any of the physicians or other healthcare providers or entities with whom we expect to do business, including future collaborators, are found not to be in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from participation in government healthcare programs, which could also affect our business.

Future legislation, and/or regulations and policies adopted by the FDA, the EMA or comparable regulatory authorities, may increase the time and cost required for us or our collaborators to conduct and complete clinical trials of our current and future product candidates.

The FDA and the EMA have each established regulations to govern the product development and approval process, as have other foreign regulatory authorities. The policies of the FDA, the EMA and other regulatory authorities may change. For example, in December 2016, the 21st Century Cures Act, or Cures Act, was signed into law. The Cures Act, among other things, is intended to modernize the regulation of drugs and spur innovation, but not all its provisions have yet been implemented. Additionally, in August 2017, the FDA issued final guidance setting forth its current thinking with respect to development programs and clinical trial designs for antibacterial drugs to treat serious bacterial diseases in patients with an unmet medical need. We cannot predict what if any effect the Cures Act or any existing or future guidance from the FDA or other regulatory authorities will have on the development of our product candidates.

Recently enacted and future legislation may increase the difficulty and cost for us and our collaborators to obtain marketing approval of and commercialize our product candidates and affect the prices we may obtain.

In the United States and some foreign jurisdictions, there have been several legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product candidates, restrict or regulate post-approval activities and affect our ability to profitably sell any product candidates for which we obtain marketing approval.

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Among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access.

Other federal health reform measures have been proposed and adopted in the United States. For example, the Medicare Access and CHIP Reauthorization Act of 2015 ended the use of the statutory formula for clinician payment and established a quality payment incentive program, also referred to as the Quality Payment Program. This program provides clinicians with two ways to participate, including through the Advanced Alternative Payment Models, or APMs, and the Merit-based Incentive Payment System, or MIPS. In November 2019, CMS issued a final rule finalizing the changes to the Quality Payment Program. It is unclear how payment reductions or the introduction of the Quality Payment Program will impact overall physician reimbursement under the Medicare program. It is also unclear if changes in Medicare payments to providers would impact such providers’ willingness to prescribe and administer our products, if approved.

Further, there has been heightened governmental scrutiny over the way companies set prices for their marketed products. For example, there have been several recent Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and patient programs, and reform government program reimbursement methodologies for drug products.

We expect that the ACA, as well as other healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and in additional downward pressure on the price that we receive for any approved product. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us or our collaborators from being able to generate revenue, attain profitability, or commercialize our drugs.

Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for drugs. We cannot be sure whether additional legislative changes will be enacted, or whether the FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals of our product candidates, if any, may be. In addition, increased scrutiny by the U.S. Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing testing and other requirements.

Our product candidates may be subject to government price controls that may affect our revenue.

There has been heightened governmental scrutiny in the United States and abroad of pharmaceutical pricing practices considering the rising cost of prescription drugs and biologics. In the United States, such scrutiny has resulted in several recent Congressional inquiries and proposed and enacted federal legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for products. At the federal level, the former Trump Administration’s budget proposal for fiscal year 2020 contained further drug price control measures that could be enacted during the 2020 budget process or in other future legislation, including, for example, measures to permit Medicare Part D plans to negotiate the price of certain drugs under Medicare Part B, to allow some states to negotiate drug prices under Medicaid, and to eliminate cost sharing for generic drugs for low-income patients. The former Trump Administration also released a “Blueprint”, or plan, to lower drug prices and reduce out of pocket costs of drugs that contains additional proposals to increase drug manufacturer competition, increase the negotiating power of certain federal healthcare programs, incentivize manufacturers to lower the list price of their products, and reduce the out-of-pocket costs of drug products paid by consumers.

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HHS has solicited feedback on some of these measures and has implemented others under its existing authority. For example, in May 2019, CMS issued a final rule to allow Medicare Advantage plans the option to use step therapy for Part B drugs beginning January 1, 2020. This final rule codified CMS’s policy change that was effective January 1, 2019. On November 20, 2020, CMS issued an interim final rule through the CMS Innovation Center whereby Medicare Part B reimbursement for “certain high-cost prescriptions drugs” would be no more than most-favored-nation price (i.e.,

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the lowest price) after adjustments, for a pharmaceutical product that the drug manufacturer sells in a member country of the Organization for Economic Cooperation and Development that has a comparable per-capita gross domestic product. On December 28, 2020, the United States District Court in Northern California issued a nationwide preliminary injunction against implementation of the interim final rule. While some of these and other measures may require additional authorization to become effective, members of Congress have and the new Biden Administration have indicated that they will continue to seek new legislative and/or administrative measures to control drug costs. At the state level, legislatures have become increasingly aggressive in passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

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Outside of the United States, particularly in the European Union, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain coverage and reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business could be harmed.

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We are subject to the U.K. Bribery Act, the U.S. Foreign Corrupt Practices Act and other anti-corruption laws, as well as export control laws, import and customs laws, trade and economic sanctions laws and other laws governing our operations.

Our operations are subject to anti-corruption laws, including the U.K. Bribery Act 2010, or the Bribery Act, the U.S. Foreign Corrupt Practices Act of 1977, as amended, or the FCPA, the U.S. domestic bribery statute contained in 18 U.S.C. §201, the U.S. Travel Act, and other anti-corruption laws that apply in countries where we do business. The Bribery Act, the FCPA and these other laws generally prohibit us and our employees and intermediaries from authorizing, promising, offering, or providing, directly or indirectly, improper or prohibited payments, or anything else of value, to government officials or other persons to obtain or retain business or gain some other business advantage.

Under the Bribery Act, we may also be liable for failing to prevent a person associated with us from committing a bribery offense. We, our collaborators, and those acting on our behalf operate in a number of jurisdictions that pose a high risk of potential Bribery Act or FCPA violations, and we participate in collaborations and relationships with third parties whose corrupt or illegal activities could potentially subject us to liability under the Bribery Act, FCPA or local anticorruption laws, even if we do not explicitly authorize or have actual knowledge of such activities. In addition, we cannot predict the nature, scope or effect of future regulatory requirements to which our international operations might be subject, or the way existing laws might be administered or interpreted.

Compliance with the Bribery Act, the FCPA and these other laws is expensive and difficult, particularly in countries in which corruption is a recognized problem. In addition, anti-corruption laws present challenges in the pharmaceutical industry, because, in many countries, hospitals are operated by the government, and doctors and other hospital employees are considered foreign officials. Certain payments to hospitals in connection with clinical trials and other work have been deemed to be improper payments to government officials and have led to enforcement actions.

We are also subject to other laws and regulations governing our international operations, including regulations administered by the governments of the United States and the United Kingdom, and authorities in the European Union, including applicable export control regulations, economic sanctions and embargoes on certain countries and persons, anti-money laundering laws, import and customs requirements and currency exchange regulations, collectively referred to as the Trade Control laws.

There is no assurance that we will be completely effective in ensuring our compliance with all applicable anti-corruption laws, including the Bribery Act, the FCPA or other legal requirements, including Trade Control laws. If we are not in compliance with the Bribery Act, the FCPA and other anti-corruption laws or Trade Control laws, we may be subject to criminal and civil penalties, disgorgement and other sanctions and remedial measures, and legal expenses, which could have an adverse impact on our business, financial condition, results of operations and liquidity. Likewise,

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any investigation of any potential violations of the Bribery Act, the FCPA, other anti-corruption laws or Trade Control laws by United States, United Kingdom or other authorities could also have an adverse impact on our reputation, our business, results of operations and financial condition. Further, the failure to comply with laws governing international business practices may result in substantial civil and criminal penalties and suspension or debarment from government contracting.

If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could harm our business.

We are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous materials, including chemicals and biological materials. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties for failure to comply with such laws and regulations.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological or hazardous materials.

In addition, we may incur substantial costs to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Our failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

Recent and potential future changes to U.S. and non-U.S. tax laws could materially adversely affect our company. 

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Existing, new or future changes in tax laws, regulations and treaties, or the interpretation thereof, in addition to tax policy initiatives and reforms under consideration in the United States or internationally and other initiatives could have an adverse effect on the taxation of international businesses. Furthermore, countries where we are subject to taxes, including the United States, are independently evaluating their tax policy and we may see significant changes in legislation and regulations concerning taxation. On December 22, 2017, President Trump signed into law the Tax Act, which significantly revised the Code. The Tax Act, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses), limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, one time taxation of offshore earnings at reduced rates regardless of whether they are repatriated, elimination of U.S. tax on foreign earnings (subject to certain important exceptions), immediate deductions for certain new investments instead of deductions for depreciation expense over time, and modifying or repealing many business deductions and credits.

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Notwithstanding the reduction in the corporate income tax rate, the overall impact of the Tax Act is uncertain and our business and financial condition could be adversely affected. The impact of this tax reform on holders of our common stock is also uncertain and could be adverse. Other legislative changes could also affect the taxation of holders of our common stock. We are unable to predict what tax reform may be proposed or enacted in the future or what effect such changes would have on our business, but such changes, to the extent they are brought into tax legislation, regulations, policies or practices, could affect our effective tax rates in the future in countries where we have operations and have an adverse effect on our overall tax rate in the future, along with increasing the complexity, burden and cost of tax compliance. We urge our stockholders to consult with their legal and tax advisors with respect to any such legislative changes and the potential tax consequences of investing in or holding our common stock. 

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Risks Related to Ownership of Our Common Stock

Innoviva, Inc. may exert a substantial influence on actions requiring stockholder vote, potentially in a manner that you do not support.

As of December 31, 2021, Innoviva, held approximately 59.9% of our issued and outstanding shares of common stock, and accordingly controls 59.9% of our voting power. Innoviva’s large ownership stake may allow it to exert a significant influence on actions requiring a stockholder vote, potentially including amendments to our certificate of incorporation, election of our board of directors, removal of any of our directors, adoption of measures that could delay or prevent a change in control or impede a merger, takeover, or other business combination involving us, and approval of other major corporate transactions. In addition, Innoviva’s stock ownership may discourage a potential acquirer from making a tender offer or otherwise attempting to obtain control of us, which in turn could reduce our stock price or prevent our stockholders from realizing a premium over our stock price. Innoviva has appointed an Observer to our Board, and retains the right to appoint two directors to our Board so long as it maintains certain thresholds of stock ownership, which it presently exceeds. As a result of its stock ownership and ability to appoint directors to our Board, Innoviva has the ability to significantly influence management and to exercise control over our business. Stockholders other than Innoviva correspondingly do not have the ability to influence management or exercise control over the business.

The trading price of our common stock may be volatile and fluctuate substantially, and you could lose all or part of your investment.

Since our initial public offering, our stock price has been and is likely to continue to be highly volatile and could be subject to wide fluctuations in response to several factors, some of which are beyond our control, including limited trading volume. The stock market in general and the market for biopharmaceutical companies have experienced extreme volatility that has often been unrelated to the operating performance of companies. As a result of this volatility, investors may not be able to sell their shares at or above the price paid for the shares. In addition to the factors discussed in this “Risk Factors” section, these factors include:

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These and other market and industry factors may cause the market price and demand for our common stock to fluctuate substantially, regardless of our actual operating performance, which may limit or prevent investors from selling their shares of our common stock at or above the price paid for the shares and may otherwise negatively affect the liquidity of our common stock. In addition, the stock market in general, and biopharmaceutical companies, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies.

Some companies that have experienced volatility in the trading price of their shares have been the subject of securities class action litigation. Any lawsuit to which we are a party, with or without merit, may result in an unfavorable judgment. We also may decide to settle lawsuits on unfavorable terms. Any such negative outcome could result in payments of substantial damages or fines, damage to our reputation or adverse changes to our business practices. Defending against litigation is costly and time-consuming and could divert our management’s attention and our resources. Furthermore, during litigation, there could be negative public announcements of the results of hearings, motions or other interim proceedings or developments, which could have a negative effect on the market price of our common stock.

The issuance of additional shares of stock, or actual or perceived sales by large holders, could depress the market price of our common stock.

Our certificate of incorporation authorizes us to issue up to 125,000,000 shares of common stock and up to 10,000,000 shares of preferred stock with such rights and preferences as may be determined by our board of directors. Subject to compliance with applicable rules and regulations, we may issue our shares of common stock or securities convertible into our common stock from time to time in connection with a financing, acquisition, investment, our equity incentive plans or otherwise. Any such issuance could result in substantial dilution to our existing stockholders and cause the trading price of our common stock to decline.

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Our common stock is concentrated in several shareholders who hold large positions. For example, Innoviva, held 59.9% of our issued and outstanding common stock and AstraZeneca held 4.5% of our issued and outstanding common stock as of December 31, 2021. If holders of large numbers of our shares sell a substantial number of our shares of common stock in the public markets, or if there is the perception that such sales could occur, such sales could depress the market price of our shares of common stock and impair our ability to raise capital through the sale of additional equity securities. We cannot predict neither the number of shares that might be sold by our current or future

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investors nor the effect that future sales of our shares of common stock would have on the market price of our shares of common stock.

Concentration of ownership of our common stock among our existing executive officers, directors and principal stockholders may prevent new investors from influencing significant corporate decisions and matters submitted to stockholders for approval.

Our executive officers, directors and current beneficial owners of 5% or more of our common stock and their respective affiliates beneficially own, in the aggregate, greater than 50% of our outstanding common stock, based on the number of shares of our common stock outstanding as of December 31, 2021. As a result, these persons, acting together, would be able to control all matters requiring stockholder approval, including the election and removal of directors, any merger, consolidation or sale of all or substantially all our assets, or other significant corporate transactions. The interests of this group of stockholders may not coincide with our interests or the interests of other stockholders. In addition, these persons, acting together, may have the ability to control the management and affairs of our company. Accordingly, this concentration of ownership may harm the market price of our common stock by: delaying, deferring, or preventing a change in control; entrenching our management and/or the board of directors; impeding a merger, consolidation, takeover, or other business combination involving us; or by discouraging a potential acquirer from making a tender offer or otherwise attempting to obtain control of us.

Provisions in our corporate charter documents and under Delaware law could make the acquisition of our company, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.

Provisions in our amended and restated certificate of incorporation and our amended and restated bylaws may discourage, delay or prevent a merger, acquisition or other change in control of our company that stockholders may consider favorable, including transactions in which you might otherwise receive a premium for your shares. These provisions also could limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of our common stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Among other things, these provisions:

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Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which prohibits a person who owns in excess of 15% of our outstanding voting stock from merging or combining with us for a period of three years after the date of the transaction in which the person acquired more than 15% of our outstanding voting stock, unless the merger or combination is approved in a prescribed manner. These provisions could discourage potential acquisition proposals and could delay or prevent a change in control transaction. They could also have the effect of discouraging others from making tender offers for our common stock, including transactions that may be in your best interests. These provisions may also prevent changes in our management or limit the price that investors are willing to pay for our stock.

We are an “emerging growth company” and because of the reduced disclosure and governance requirements applicable to emerging growth companies, our common stock may be less attractive to investors.

We are an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and we intend to take advantage of some of the exemptions from reporting requirements that are applicable to other public companies that are not emerging growth companies, including:

We currently take advantage of some or all these reporting exemptions and we may continue to do so until we are no longer an emerging growth company, or EGC. We will remain an EGC until the earlier of (1) the last day of 2023, (2) the last day of the fiscal year in which we have total annual gross revenue of at least $1.07 billion, (3) the last day of the fiscal year in which we are deemed to be a large accelerated filer, which means the market value of our common stock that is held by non-affiliates exceeds $700 million as of the prior June 30th, and (4) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period.

Under Section 107(b) of the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards until those standards apply to private companies. We have irrevocably elected not to avail ourselves of this exemption from new or revised accounting standards and, therefore, we are subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

If we fail to maintain proper and effective internal controls, our ability to produce accurate financial statements on a timely basis could be impaired.

The Sarbanes-Oxley Act requires, among other things, that we maintain effective disclosure controls and procedures and internal control over financial reporting.

Our internal control over financial reporting will not prevent or detect all errors and all fraud. A control system, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the control system’s objectives will be met. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all control issues and instances of fraud will be detected.

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If we are not able to comply with the requirements of Section 404 of the Sarbanes-Oxley Act in a timely manner, or if we are unable to maintain proper and effective internal controls, we may not be able to produce timely and accurate financial statements. If that were to happen, the market price of our common stock could decline, and we could be subject to sanctions or investigations by Nasdaq, the SEC, or other regulatory authorities.

We have broad discretion in the use of our cash and cash equivalents and may invest or spend them in ways with which you do not agree and in ways that may not increase the value of your investment.

Our management will have broad discretion in the application of our cash and cash equivalents and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our common stock. The failure by our management to apply these funds effectively could result in financial losses that could have a negative impact on our business, cause the price of our common stock to decline and delay the development of our product candidates and preclinical program. Pending their use, we may invest our cash and cash equivalents in a manner that does not produce income or that loses value.

Because we do not anticipate paying any cash dividends on our common stock in the foreseeable future, capital appreciation, if any, will be your sole source of gains and you may never receive a return on your investment.

You should not rely on an investment in our common stock to provide dividend income. Pursuant to our Business Transfer and Subscription Agreement with AstraZeneca, we also agreed to pay AstraZeneca a one-time milestone payment of $5.0 million within three months of achieving a specified cumulative net sales milestone for durlobactam. This milestone payment will be automatically waived should our common stock trade on Nasdaq at or above a specified price at the time we achieve such specified cumulative net sales milestone for durlobactam, subject to adjustment for share splits, dividends and other similar events. We are also obligated to pay AstraZeneca a one-time milestone payment of $10.0 million within two years of achieving the first commercial sale of zoliflodacin. Following the achievement of either milestone, we are not permitted to pay dividends or make other distributions to any of our stockholders until the applicable milestone payment has been paid in full or otherwise waived. We have never declared or paid a dividend on our common stock to date, and we currently intend to retain our future earnings, if any, to fund the development and growth of our business. As a result, capital appreciation, if any, on our common stock will be your sole source of gains for the foreseeable future. Investors seeking cash dividends should not purchase our common stock.

We incur significantly increased costs because of operating as a company whose common stock is publicly traded in the United States, and our management is required to devote substantial time to new compliance initiatives.

As a public company in the United States, we incur significant legal, accounting and other expenses that we did not incur previously. These expenses will likely be even more significant after we no longer qualify as an EGC. The Sarbanes-Oxley Act, the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of Nasdaq and other applicable securities rules and regulations impose various requirements on public companies in the United States, including the establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Our senior management and other personnel devote a substantial amount of time to these compliance initiatives. Moreover, these rules and regulations have increased and will continue to increase our legal and financial compliance costs and will make some activities more time-consuming and costly. For example, we expect that these rules and regulations may make it more difficult and more expensive for us to obtain director and officer liability insurance, which in turn could make it more difficult for us to attract and retain qualified senior management personnel or members for our board of directors.

However, these rules and regulations are often subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices.

Pursuant to Section 404, we will be required to furnish a report by our senior management on our internal control over financial reporting. However, while we remain an EGC, we will not be required to include an attestation report on internal control over financial reporting issued by our independent registered public accounting firm. To

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prepare for compliance with Section 404, we will be engaged in a process to document and evaluate our internal control over financial reporting, which is both costly and challenging. In this regard, we will need to continue to dedicate internal resources, potentially engage outside consultants and adopt a detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to improve control processes as appropriate, validate through testing that controls are functioning as documented and implement a continuous reporting and improvement process for internal control over financial reporting. Despite our efforts, there is a risk that we will not be able to conclude, within the prescribed timeframe or at all, that our internal control over financial reporting is effective as required by Section 404. If we identify one or more material weaknesses, it could result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of our consolidated financial statements.

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General Risk Factors

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Significant disruptions of our information technology systems or data security incidents could result in significant financial, legal, regulatory, business, and reputational harm to us.

We are increasingly dependent on information technology systems and infrastructure, including mobile technologies, to operate our business. In the ordinary course of our business, we collect, store, process and transmit substantial amounts of sensitive information, including intellectual property, proprietary business information, personal information and other confidential information. It is critical that we do so in a secure manner to maintain the confidentiality, integrity and availability of such sensitive information. We have also outsourced elements of our operations, including elements of our information technology infrastructure, to third parties and, as a result, we manage several third-party vendors who may or could have access to our computer networks or our confidential information. In addition, many of those third parties in turn subcontract or outsource some of their responsibilities to other third parties. While all information technology operations are inherently vulnerable to inadvertent or intentional security breaches, incidents, attacks and exposures, the accessibility and distributed nature of our information technology systems, and the sensitive information stored on those systems, make such systems potentially vulnerable to unintentional or malicious, internal and external attacks on our technology environment. Potential vulnerabilities can be exploited from inadvertent or intentional actions of our employees, third-party vendors, business partners, or by malicious third parties. Attacks of this nature are increasing in their frequency, levels of persistence, sophistication and intensity, and are being conducted by sophisticated and organized groups and individuals with a wide range of motives (including industrial espionage) and expertise, including organized criminal groups, “hacktivists,” nation states and others. In addition to the extraction of sensitive information, such attacks could include the deployment of harmful malware, ransomware, denial-of-service attacks, social engineering and other means to affect service reliability and threaten the confidentiality, integrity and availability of information. In addition, the prevalent use of mobile devices increases the risk of data security incidents.

Significant disruptions of our, our third-party vendors’ or business partners’ information technology systems or other similar data security incidents could adversely affect our business operations and result in the loss, misappropriation, and unauthorized access, use or disclosure of, or the prevention of access to, sensitive information, which could result in financial, legal, regulatory, business and reputational harm to us. In addition, information technology system disruptions, whether from attacks on our technology environment or from computer viruses, natural disasters, terrorism, war and telecommunication and electrical failures, could result in a material disruption of our development programs and our business operations. For example, the loss of clinical trial data from completed or future clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data.

There is no way of knowing with certainty whether we have experienced any data security incidents that have not been discovered. While we have no reason to believe this to be the case, attackers have become very sophisticated in the way they conceal access to systems, and many companies that have been attacked are not aware that they have been attacked. Any event that leads to unauthorized access, use or disclosure of personal information, including personal information regarding our patients or employees, could disrupt our business, harm our reputation, compel us to comply with applicable federal and state breach notification laws and foreign law equivalents, subject us to time-consuming, distracting and expensive litigation, regulatory investigation and oversight, mandatory corrective action, require us to verify the correctness of database contents, or otherwise subject us to liability under laws, regulations and contractual

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obligations, including those that protect the privacy and security of personal information. This could result in increased costs to us and result in significant legal and financial exposure and reputational harm. In addition, any failure or perceived failure by us or our vendors or business partners to comply with our privacy, confidentiality or data security-related legal or other obligations to third parties, or any further security incidents or other inappropriate access events that result in the unauthorized access, release or transfer of sensitive information, which could include personally identifiable information, may result in governmental investigations, enforcement actions, regulatory fines, litigation, or public statements against us by advocacy groups or others, and could cause third parties, including clinical sites, regulators or current and potential partners, to lose trust in us, or we could be subject to claims by third parties that we have breached our privacy- or confidentiality-related obligations. Moreover, data security incidents and other inappropriate access can be difficult to detect, and any delay in identifying them may lead to increased harm of the type described above. While we have implemented security, measures intended to protect our information technology systems and infrastructure, there can be no assurance that such measures will successfully prevent service interruptions or security incidents.

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If we engage in future acquisitions or strategic collaborations, this may increase our capital requirements, dilute our stockholders, cause us to incur debt or assume contingent liabilities and subject us to other risks.

From time to time, we may evaluate various acquisitions and strategic collaborations, including licensing or acquiring complementary drugs, intellectual property rights, technologies or businesses, as deemed appropriate to carry out our business plan. Any potential acquisition or strategic collaboration may entail numerous risks, including:

Tax authorities may disagree with our positions and conclusions regarding certain tax positions, resulting in unanticipated costs, taxes, or non-realization of expected benefits.

A tax authority may disagree with tax positions that we have taken, which could result in increased tax liabilities. For example, the Internal Revenue Service or another tax authority could challenge our allocation of income by tax jurisdiction and the amounts paid between our affiliated companies pursuant to our intercompany arrangements and transfer pricing policies, including amounts paid with respect to our intellectual property development. Similarly, a tax authority could assert that we are subject to tax in a jurisdiction where we believe we have not established a taxable connection, often referred to as a “permanent establishment” under international tax treaties, and such an assertion, if successful, could increase our expected tax liability in one or more jurisdictions. The foregoing are only selected examples of potential challenges, and other tax positions we have taken or may take in the future could become the subject of disputes with one or more tax authorities. A tax authority may take the position that material income tax liabilities, interest and penalties are payable by us, in which case, we expect that we might contest such assessment.

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Contesting such an assessment may be lengthy and costly and if we were unsuccessful in disputing the assessment, the implications could increase our anticipated effective tax rate, where applicable.

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Recent Sales of Unregistered Equity Securities

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On June 11, 2020, we completed a private placement transaction, the First Private Placement, in which we sold to Innoviva a total of 14,000,000 shares of our common stock and issued warrants to purchase an additional 14,000,000 shares of our common stock, with an exercise price per share of $2.50. The First Private Placement was closed in two tranches for total aggregate gross proceeds of $35.0 million.

On September 1, 2020, we completed a private placement transaction pursuant to a securities purchase agreement with the purchasers named therein, or the Investors, in which we sold to the Investors a total of 8,183,878 shares of our common stock, issued warrants to purchase an additional 9,345,794 shares of our common stock, with an exercise price per share of $2.675, and issued pre-funded warrants to purchase an additional 1,161,916 shares of our common stock, with an exercise price per share of $0.001, collectively, the Second Private Placement. The Second Private Placement resulted in total aggregate gross proceeds of approximately $25.0 million.

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On June 11, 2021, we completed a private placement transaction, the Third Private Placement, in which we sold to Innoviva a total of 10,000,000 shares of our common stock and issued warrants to purchase an additional 10,000,000 shares of our common stock, with an exercise price per share of $2.00. The Third Private Placement was closed in two tranches for total aggregate gross proceeds of $20.0 million.

Purchases of Equity Securities by the Issuer and Affiliated Purchasers

None.

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Item 6. Reserved

Not applicable.

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data set, we believe will also support a regulatory submission in China. Zai Lab has an exclusive license to develop and commercialize SUL-DUR in mainland China as well as the broader Asia-Pacific region.

Our second late-stage product candidate, zoliflodacin, is a novel orally administered molecule being developed for the treatment of uncomplicated gonorrhea. The bacterial pathogen responsible for gonorrhea is Neisseria gonorrhoeae, or N. gonorrhoeae, including multidrug-resistant strains. Intramuscular injections of ceftriaxone now represent the only U.S. Centers for Disease Control and Prevention, or CDC, recommended treatment option for the estimated 1.6 million annual cases of gonorrhea in the United States. We believe there is a growing unmet need for a single-dose oral antibiotic that will reliably treat patients with gonorrhea, including infections caused by multidrug-resistant strains of N. gonorrhoeae, which are emerging globally. The Phase 3 registration trial, initiated in September 2019, is sponsored by our nonprofit collaborator, the Global Antibiotic Research and Development Partnership, or GARDP, which as the sponsor is also responsible for all Phase 3 clinical trial and pharmaceutical development expenses. GARDP has commercial rights to zoliflodacin in up to 168 low- and select middle-income countries, while Entasis retains commercial rights in the major markets in North America, Europe and Asia-Pacific. Based on current enrollment rates, we anticipate the trial to be fully enrolled in 2023.

Our third product candidate is ETX0282CPDP which is a combination of a novel, oral BLI, ETX0282, with cefpodoxime proxetil or CPDP, which has the potential to address complicated urinary tract infections, or cUTIs, including those caused by multidrug-resistant Enterobacteriaceae. We believe there is a significant unmet need for new oral antibiotics to reliably treat the estimated 3 to 4 million patients diagnosed annually with cUTIs. We have reported preliminary Phase 1 trial results, and we are now seeking a partner to help further advance ETX0282CPDP through additional clinical trials. This program was previously supported by the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator program, or CARB-X.

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We are also advancing the development of a novel class of antibiotics, non β-lactam inhibitors of penicillin-binding proteins, or NBPs. We believe NBPs constitute a potential new class of Gram-negative antibacterial agents that are designed to target a broad spectrum of multidrug resistant bacterial pathogens that overcome the main source of β-lactam resistance which is driven by β-lactamase activity. This novel class of agents is designed to potentially target a broad spectrum of multidrug resistant bacterial pathogens that are part of the CDC/World Health Organization, or WHO, list of high unmet medical need or ESKAPE pathogens. We selected ETX0462 as the initial clinical candidate for this program and with support from CARB-X we are currently working to complete additional pre-clinical activities to enable the program to advance into a Phase 1 clinical trial. In June 2020, we were awarded a contract from the National Institutes of Health, or NIH, to support research towards developing additional NBP molecules with expanded Gram-negative spectrum from this novel class. This research program, designated NBP2, is attempting to target Klebsiella, Pseudomonas and E. coli from the ESKAPE list of pathogens. In July 2021, we successfully completed the first milestones for the program and have been awarded the Option 1 Period of the program to proceed with further optimization, beginning August 1, 2021. Subject to achieving pre-defined milestones, the contract is expected to sufficiently fund activities to achieve submission of an Investigational New Drug, or IND, application to the FDA.

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Since our inception in May 2015, we have devoted substantially all of our resources to organizing and staffing our company, business planning, raising capital, discovering product candidates and securing related intellectual property rights, conducting discovery and development activities for our programs and planning for potential commercialization. We do not have any products approved for sale and have not generated any revenue from product sales. As of December 31, 2021, we have funded our operations primarily with net cash proceeds of $104.2 million from the sale of our preferred stock, net cash proceeds of $65.6 million from the sale of common stock in our initial public offering, and net cash proceeds of $78.5 million from the sale of common stock, warrants and pre-funded warrants in private placements and at-the-market sales to certain investors in 2021 and 2020. We have also either directly received funding or financial commitments from, or have had our program activities conducted and funded by, the U.S. government through our arrangements with NIAID, CARB-X, and the U.S. Department of Defense, or DOD, and we have received non-profit awards from GARDP and upfront and milestone payments from our license and collaboration agreement with Zai Lab.

Funding Arrangements

NIH

In June 2020, we entered into a contract with NIAID, part of the NIH, with an effective date of July 1, 2020. The contract consists of an initial award of approximately $3.0 million, with the potential to increase it up to $15.5 million, that will be used to develop novel molecules from our NBP platform. In July 2021, we successfully completed the first milestones for the program associated with the initial award and have been awarded the Option 1 Period of the program to proceed with further optimization, beginning August 1, 2021. This option consists of any additional $2.9 million, bringing the total award to $5.9 million. Funding from the contract will support research towards developing molecules with expanded Gram-negative spectrum against antibiotic-resistant bacterial pathogens including E. coli, Acinetobacter, Pseudomonas and Klebsiella. Through December 31, 2021, we had received $3.2 million in payments and we have recorded $3.9 million of grant income under this funding arrangement.

CARB-X

In March 2017 and October 2017, we entered into funding arrangements with the Trustees of Boston University to utilize funds from the U.S. government, through the CARB-X program, for support of our ETX0282CPDP and ETX0462 programs. These funding arrangements could cover up to $18.5 million of our specified research expenditures from April 2017 through May 2023. Through December 31, 2021, we had received $12.6 million in payments and we have recorded $12.9 million of grant income under these funding arrangements. The remaining $5.6 million of grant income that could be recorded is related to our ETX0462 program.

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License and Collaboration Agreements

GARDP

In July 2017, we entered into a collaboration agreement with GARDP for the development and commercialization of a product candidate containing zoliflodacin in certain countries. Under the terms of the

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collaboration agreement, GARDP will fully fund the ongoing Phase 3 registration trial, including the manufacture and supply of the product candidate containing zoliflodacin, in uncomplicated gonorrhea.

Zai Lab

In April 2018, we entered into a license and collaboration agreement with Zai Lab pursuant to which Zai Lab licensed exclusive rights to durlobactam and SUL-DUR in the Asia-Pacific region. Under the terms of the agreement, Zai Lab will fund most of our registration trial costs in China for SUL-DUR, with the exception of Phase 3 patient drug supply of licensed product. As of December 31, 2021, we have received net payments of $15.8 million, representing the $5.0 million upfront payment, $7.0 million of milestone payments, $0.6 million of research support payments and $5.4 million of certain other reimbursable registration trial costs, less applicable taxes of $2.2 million, from Zai Lab and we have recognized revenue of $12.0 million under this agreement.

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include fees incurred under service, license or option agreements. We do not allocate employee costs or facility expenses to specific programs because these costs are deployed across multiple programs and, accordingly, are not separately classified. We primarily use internal resources and our own employees to conduct our research and discovery as well as for managing our preclinical development, process development, manufacturing and clinical development activities.

To date, substantially all of our research and development expenses have been related to the preclinical and clinical development of our product candidates and preclinical programs. The following table shows our research and development expenses by development program and type of activity for the years ended December 31, 2021 and 2020:

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Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. It is difficult to determine with certainty the duration and completion costs of our current or future preclinical programs and clinical trials of our product candidates, or if, when or to what extent we will generate revenues from the commercialization and sale of any of our product candidates that obtain regulatory approval. We may never succeed in achieving regulatory approval for any of our product candidates.

The duration, costs and timing of clinical trials and development of our product candidates and preclinical program will depend on a variety of factors that include, but are not limited to, the following:

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Any changes in the outcome of any of these factors with respect to the development of our product candidates could mean a significant change in the costs and timing associated with the development of these product candidates. In addition, the probability of success for each product candidate will depend on numerous factors, including competition, manufacturing and supply, and commercial viability. We will determine which programs to pursue and how much to fund each program based on the scientific and clinical success of each product candidate, as well as an assessment of each candidate’s commercial potential.

General and Administrative Expenses

General and administrative expenses consist of salaries and benefits and stock-based compensation expense for personnel in executive, finance and administrative functions. General and administrative costs also include facilities-related costs not otherwise included in research and development expenses and professional fees for legal, patent, consulting, insurance, accounting and audit services.

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support our continued research, development and commercialization activities of our product candidates. Additionally, if and when we believe a regulatory approval of a product candidate appears likely, we anticipate an increase in payroll and other employee-related expenses as a result of our preparation for commercial operations, especially as it relates to the sales and marketing functions for that product candidate.

Other Income

Grant Income

Grant income consists of income recognized in connection with grants we received under our funding arrangements with the Trustees of Boston University through the CARB-X program, as well as amounts received under our NIH contract. Grant income is recognized in the period during which the related specified expenses are incurred.

Interest Income

Interest income consists of interest earned on our cash and investment balances, which are primarily held in money market funds and U.S. Treasury Securities.

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Research and Development Expenses

Research and development expenses were $37.1 million for the year ended December 31, 2021, compared to $41.0 million for the year ended December 31, 2020. The decrease of $3.9 million was primarily due to a decrease of $6.5 million in clinical development expenses related to the advancement of SUL-DUR; offset in part by an increase of $2.1 million of personnel expenses associated with higher headcount, higher salaries and higher stock-based compensation expense resulting from options and restricted stock units granted during the year ended December 31, 2021, an increase of $0.3 million in preclinical and clinical development expenses related to the advancement of ETX0462 and an increase of $0.3 million in other preclinical programs. The decrease in preclinical and clinical development expenses of $6.5 million associated with SUL-DUR was primarily due to a decrease of $5.4 million in clinical trial costs, a decrease of $1.3 million in drug manufacturing costs, and a decrease of $0.4 million in commercial readiness activities; partially offset by an increase of $0.6 million in NDA filing support fees. The increase in clinical development expenses of $0.3 million associated with the advancement of ETX0462 was primarily due to an increase of $0.7 million in drug manufacturing costs, offset by a decrease of $0.4 million in toxicology studies.

General and Administrative Expenses

General and administrative expenses were $15.2 million for the year ended December 31, 2021, compared to $13.2 million for the year ended December 31, 2020. The increase of $2.0 million was driven by an increase of $1.0 million in personnel expenses associated with higher headcount and higher salaries, an increase of $0.6 million in professional expenses and an increase of $0.4 million in insurance expenses. The increase of $0.6 million in professional expenses was primarily due to an increase of $0.3 million in consulting expenses, an increase of $0.2 million in investor and public relations expenses and an increase of $0.1 million in legal expenses.

Other Income

Other income was $5.2 million for the year ended December 31, 2021, compared to $3.7 million for the year ended December 31, 2020. The increase of $1.4 million was due to an increase in grant income of $1.6 million from our agreements with CARB-X and NIH; offset by a decrease in interest income of $0.2 million.

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A change in the outcome of any of these variables with respect to the development of any of our product candidates would significantly change the costs and timing associated with the development of that product candidate.

We will not generate revenue from product sales unless and until we or a collaborator successfully complete clinical development and obtain regulatory approval for our current and future product candidates. If we obtain regulatory approval for any of our product candidates that we ultimately decide to commercialize on our own, we will incur significant expenses related to commercialization, including developing our internal commercialization capability to support product sales, marketing and distribution.

As a result, we will need substantial additional funding to support our continuing operations and to pursue our growth strategy. Until such time, if ever, when we can generate substantial product revenue, we expect to finance our cash needs through a combination of equity offerings, debt financings and potential collaboration, license and development agreements. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.

If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may be required to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our drug development or future commercialization efforts or grant rights to a third party to develop and market product candidates that we would otherwise prefer to develop and market ourselves. Our failure to raise capital as and when needed would compromise our ability to pursue our business strategy.

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We will also continue to incur costs as a public company that we did not incur or incurred at lower rates prior to our initial public offering, including increased fees payable to the nonemployee members of our board of directors, increased personnel costs, increased director and officer insurance premiums, audit and legal fees, investor relations fees and expenses for compliance with public-company reporting requirements under the Exchange Act and rules implemented by the SEC and Nasdaq.

Because of the numerous risks and uncertainties associated with product development, we are unable to predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

At-the-Market Facility

In August 2021, we entered into a Controlled Equity Offering Sales Agreement, or Sales Agreement, with Cantor Fitzgerald & Co, or Cantor, for the offer and sale of up to $17.5 million of its common stock at the then current market prices in amounts to be determined from time to time. On October 21, 2021, the Company sold an aggregate of 200,000 shares of common stock at a sale price of $3.25 per share, for gross proceeds of $0.7 million. Proceeds, net of fees, were $0.6 million.

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Innoviva, Inc. Securities Purchase Agreement

On May 3, 2021, we entered into a securities purchase agreement, or the Third Securities Purchase Agreement, with a subsidiary Innoviva, Inc., or Innoviva, pursuant to which we agreed to issue and sell to the Innoviva subsidiary, in a private placement up to 10,000,000 newly issued shares of our common stock at $2.00 per share and warrants to purchase up to 10,000,000 shares of common stock, each with an exercise price per share of $2.00, collectively the Third Private Placement. The warrants will be exercisable immediately and will have a five-year term.

The Third Private Placement occurred in two tranches. At the closing of the first tranche, or the First Closing, which occurred on May 3, 2021, Innoviva purchased 3,731,025 shares of common stock and warrants to purchase 3,731,025 shares of common stock, for aggregate gross proceeds of $7.5 million. At the closing of the second tranche, or the Second Closing, which occurred on June 30, 2021, Innoviva purchased the remaining 6,268,975 shares of common stock and warrants to purchase 6,268,975 shares of common stock for aggregate gross proceeds of $12.5 million.

As of December 31, 2021, Innoviva owns approximately 59.9% of our outstanding common stock, without giving effect to the potential exercise of warrants. On February 1, 2022, our Board of Directors received a preliminary, non-binding proposal from Innoviva to acquire all the outstanding equity securities of the Company that are not currently owned by Innoviva for a per share consideration of $1.80 payable in cash. The offer letter delivered by Innoviva to our Board of Directors is publicly available in the Schedule 13D amendment dated February 1, 2022, filed by Innoviva with the SEC. Our Board of Directors, which does not include any members appointed by or affiliated with Innoviva, has retained MTS Health Partners, L.P. and Covington & Burling, LLP to explore alternatives and to assist the board of directors in its evaluation of the proposal consistent with fiduciary duties.

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On February 17, 2022, we entered into a securities purchase agreement, or the Fourth Securities Purchase Agreement, with a subsidiary of Innoviva, pursuant to which we issued and sold to Innoviva, in a private placement which closed on February 18, 2022, a convertible promissory note having a principal amount of $15.0 million, or Convertible Note. The Convertible Note is convertible at maturity at the election of us or Innoviva into shares of our common stock at a conversion price of $1.48 per share of common stock and warrants to purchase an equal number of shares of common stock with an exercise price of $1.48 per share of common stock, or the Warrants. The Convertible Note will also be convertible at the option of Innoviva if we engage in certain capital markets transactions, asset sales or royalty transactions. If we are acquired prior to the maturity date of the Convertible Note, the Convertible Note will be payable in cash at the time of such acquisition. The Convertible Note will mature on August 18, 2022 and bears interest at a rate of 0.59% per annum to, but excluding, the date of repayment or conversion of the Convertible Note. From and

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including the date of maturity, if not converted, the Convertible Note will bear interest at a rate of 10.00% per annum to, but excluding, the date of repayment or conversion of the Convertible Note.

The Convertible Note and the Warrants will have provisions that preclude conversion or exercise, respectively, if such conversion or exercise would result in the issuance of more than 19.99% of the our currently outstanding common stock in the aggregate prior to obtaining stockholder approval.

Registration Rights Agreement

On February 18, 2022, we and Innoviva entered into a registration rights agreement, or the Registration Rights Agreement, pursuant to which, among other things, we must prepare and file with the Securities and Exchange Commission, or the SEC, a registration statement with respect to the resale of shares of common stock and the warrants issuable upon conversion of the Convertible Note and shares of common stock issuable upon exercise of the Warrants.

Operating Activities

During the year ended December 31, 2021, operating activities used $43.0 million of cash, resulting from our net loss of $47.1 million partially offset by non-cash charges of $4.1 million. Non-cash charges were primarily comprised of stock-based compensation expense of $4.0 million.

During the year ended December 31, 2020, operating activities used $45.4 million of cash, resulting from our net loss of $50.5 million partially offset by non-cash charges of $3.1 million and net cash provided by changes in operating assets and liabilities of $2.0 million. Net cash provided by changes in operating assets and liabilities for the year ended December 31, 2020 consisted primarily of a $1.9 million decrease in other assets, a $1.0 million increase in accrued expenses and other liabilities, and a $0.4 million decrease in prepaid expenses. These were partially offset by a $0.7 million increase in grants receivable and a $0.6 million decrease in accounts payable.

Investing Activities

During the year ended December 31, 2021, net cash used in investing activities was $70,000, consisting of purchases of property and equipment.

During the year ended December 31, 2020, net cash provided by investing activities was $25.0 million, consisting primarily of proceeds from maturities of short-term investments.

Financing Activities

During the year ended December 31, 2021, net cash provided by financing activities was $22.1 million, which consisted of $20.0 million of proceeds from the issuance of common stock and warrants in the Third Private Placement, net of financing costs, $1.8 million of proceeds from the exercise of warrants, and $0.4 million of proceeds from the sale of common stock related to our at-the-market offering.

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During the year ended December 31, 2020, net cash provided by financing activities was $57.7 million, which consisted of proceeds from the issuance of common stock and warrants in the First Private Placement and Second Private Placement, net of issuance costs.

Off-Balance Sheet Arrangements

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the SEC.

Critical Accounting Policies and Significant Judgments and Estimates

Our consolidated financial statements are prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in more detail in Note 2 , Summary of Significant Accounting Policies, in the accompanying notes to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Research and Development Expenses

All research and development expenses are expensed as incurred. Research and development expenses comprise costs incurred in performing research and development activities, including compensation, benefits and other employee costs; equity‑based compensation expense; laboratory and clinical supplies and other direct expenses; facilities expenses; overhead expenses; fees for contractual services, including preclinical studies, clinical trials, clinical manufacturing and raw materials; and other external expenses. Nonrefundable advance payments for research and development activities are capitalized and expensed over the related service period or as goods are received. When third-party service providers’ billing terms do not coincide with our period-end, we are required to make estimates of our obligations to those third parties, including clinical trial costs, contractual service costs and costs for supply of our drug candidates, incurred in a given accounting period and record accruals at the end of the period. We base our estimates on our knowledge of the research and development programs, services performed for the period and the expected duration of the third-party service contract, where applicable.

Recent Accounting Pronouncements

Refer to Note 2, Summary of Significant Accounting Policies, in the accompanying notes to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K for a discussion of recent accounting pronouncements.

Emerging Growth Company Status

The Jumpstart Our Business Startups Act of 2012 permits an “emerging growth company” such as us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have irrevocably elected to “opt out” of this provision and, as a result, we will comply with new or revised accounting standards when they are required to be adopted by public companies that are not emerging growth companies.

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(a)(3) Exhibits.

The exhibits listed below are filed as part of this Form 10-K other than Exhibit 32.1, which shall be deemed furnished.

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