CPRX Catalyst Pharmaceuticals Inc

Catalyst Pharmaceuticals, Inc. ("Catalyst") (Nasdaq: CPRX), a commercial-stage, patient-centric biopharmaceutical company focused on in-licensing, developing and commercializing novel high-quality medicines for patients living with rare diseases, today announced that multiple abstracts highlighting FYCOMPA® (perampanel) CIII will be presented at the upcoming 35th International Epilepsy Congress (“IEC”) taking place on September 2 – 6, 2023 in Dublin, Ireland. These are presentations by Eisai Co., Ltd. ("Eisai"), which holds the rights to FYCOMPA in countries and regions outside the U.S. Some abstracts will also be considered for publication in Epilepsia following the IEC.

The accepted abstracts and presentations detail the results from clinical and real-world studies, further documenting the uses of perampanel in both focal and generalized epilepsy across a diverse range of patients.

“These findings, which are being presented at IEC, further validate and add to the growing body of evidence supporting the benefits of perampanel in the treatment of seizure disorders,” said Gary Ingenito, MD, PhD, Chief Medical and Regulatory Officer of Catalyst. “We are pleased this investigative work will be presented at such a prestigious forum.”

Details of the Accepted Abstracts are as follows:

Title: Perampanel for Treatment of Focal and Generalised Epilepsy in Everyday Clinical Practice: Evidence from PERMIT 2Authors: Eugen Trinka, Robert Wechsler, Wendyl D’Souza, Tony Wu, Imad Najm, Leock Ngo, Rob McMurray, Vicente VillanuevaOral Presentation number: 370Oral Presentation Session Name: Drug Therapy 1Session: Sunday, September 3, 2023, at 3:30 PM-4:30 PM BST(Eugen Trinka will present for 10 minutes: 3:35 PM-3:45 PM)Presenter: Eugen TrinkaLocation: Room Liffey B

Title: Study 603: Analysis of Effectiveness and Safety of Perampanel in a Multicentre, Retrospective Study in Patients from Korea with Focal-Onset Seizures who Converted to MonotherapyAuthors: Sung Chul Lim, Won Gu Lee, Dong Wook Kim, Kwang Ki Kim, Young-Min Shon, Jihyun Park, Yoona Lee, Dae-Won SeoPoster number: P048Digital Poster* Session and Rapid-Fire Presentation Name:  Drug Therapy 2Rapid Fire Presentation (2-minute session):Time and Date: Sunday, September 3, 2023, at 2:00 PM-2:30 PM BSTPresenter: Sung Chul LimLocation: Digital Poster Station: Level 3 Foyer - Station C

Title: ELEVATE Study 410: Assessment of Cognition (EpiTrack®) Following Perampanel (Monotherapy/First Adjunctive) in Patients with Epilepsy and a History of Psychiatric/Behavioral EventsAuthors: Vineet Punia, Omar Samad, Stella Ngo, Dinesh Kumar, Manoj Malhotra  Poster number: P149In-person & Digital Poster Session Name:  Drug TherapyPresentation: Monday, September 4, 2023, at 1:30 PM-3:00 PM BSTPresenter: Vineet PuniaLocation: Poster Hall

Title: A Mirroring Clinical Practice Study of Perampanel in Adults and Adolescents (AMPA): Assessment of Impact of Perampanel on Seizure Control, Sleep and Quality of LifeAuthors: Giovanni Assenza, Martina Chiacchiaretta, Anna Patten, Ricardo Sáinz-Fuertes, Anna GentilePoster number: P240Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: Perampanel for Treatment of Adolescent Patients (Aged ≥12 to <18 years): Real-World Evidence from PERMIT 2Authors: Francisco José Gil-López, Patricia Penovich, Rohit Shankar, Takamichi Yamamoto, Omar Samad, Eugen Trinka, Vicente VillanuevaPoster number: P364Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: Real-World Experience of Treating Patients Aged <12 Years with PerampanelAuthors: Adrián Garcia-Ron, Michael Chez, Stéphane Auvin, Tony Wu, Wendyl D´Souza, Leock Y Ngo, Omar Samad, Vicente VillanuevaPoster number: P366Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: Perampanel for Treatment of Focal and Generalised Epilepsy in Elderly Patients (Aged ≥65 years) in Clinical Practice: Evidence from PERMIT 2 Authors: Motoki Inaji, James Wheless, Rob McMurray, Ricardo Sainz Fuertes, Alexandra Astner-Rohracher, Dong Wook Kim, Eugen Trinka, Claudio Liguori, Vicente VillanuevaPoster number: P367Digital Poster* Session and Rapid-Fire Presentation Name:  Drug Therapy 2Rapid Fire Presentation (2-minute session):Time and Date: Saturday, September 2, 2023, at 2:00 PM-2:30 PM BSTLocation: Digital Poster Station: Level 3 Foyer - Station C

Title: Perampanel for Treatment of Asian Patients with Focal and Generalised Epilepsy in Clinical Practice: Evidence from PERMIT 2Authors: Tony Wu, James Wheless, Dong Wook Kim, Taoufik Alsaadi, Kousuke Kanemoto, Yotin Chinvarun, Amitabh Dash, Vicente VillanuevaPoster number: P371Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: Treatment of Adult Epilepsy Patients with Perampanel: Evidence from Real-World StudiesAuthors: Adam Strzelczyk, Eric Segal, Tim Wehner, Leock Y Ngo, Ricardo Sainz Fuertes, Mar Carreño, Tony Wu, Bernhard J. Steinhoff, Vicente VillanuevaPoster number: P373Digital Poster* Session and Rapid-Fire Presentation Name:  Drug Therapy 4Rapid Fire Presentation (2-minute session):Time and Date: Monday, September 4, 2023, at 2:00 PM-2:30 PM BSTLocation: Digital Poster Station: Level 3 Foyer - Station C

Title: Study 512 Design: Perampanel as First Adjunctive Therapy in Patients Aged ≥12 Years with Focal-Onset Seizures or Generalised Tonic-Clonic Seizures Associated With Genetic Generalised Epilepsy Authors: Sergey Burd, Giovanni Assenza, Sofia Quintas, Francisco José Gil López, Jan Wagner, Anna Patten, Ricardo Sáinz-Fuertes, Stanislas Lagarde, Tobias Sejbaek, Pavel Vlasov, Vadim Kharkovskiy, Anna LebedevaPoster number: P505Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: PERPRISE (PERampanel in patients with PRImary or SEcondarily generalised seizures): First Interim Analysis of the Observational Study Assessing Perampanel as the Only Adjunctive TherapyAuthors: Bernhard J Steinhoff, Tobias Goldmann, Yaroslav WinterPoster number: P534Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: Outcomes by Seizure Type from A Mirroring Clinical Practice Study of Perampanel in Adults and Adolescents (AMPA)Authors: Sara Casciato, Martina Chiacchiaretta, Paola Mansi, Ricardo Sáinz-Fuertes, Anna Patten, Anna GentilePoster number: P529Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

Title: ELEVATE Study 410: Analysis of Time to First Seizure with Perampanel as Monotherapy or First Adjunctive Therapy in Patients with Focal-Onset Seizures or Generalised Tonic-Clonic SeizuresAuthors: Pavel Klein, Omar Samad, Leock Y Ngo, Dinesh Kumar, Manoj MalhotraPoster number: P540Digital Poster* (Available on the Congress app, online platform, and digital poster terminals at the congress venue; Q&A chat box function also available)

About Catalyst PharmaceuticalsWith exceptional patient focus, Catalyst is committed to developing and commercializing innovative first-in-class medicines that address rare neurological and epileptic diseases. Catalyst’s flagship U.S. commercial product is FIRDAPSE® (amifampridine) Tablets 10 mg, approved for the treatment of Lambert-Eaton myasthenic syndrome ("LEMS") for adults and for children ages six to seventeen. In January 2023, Catalyst acquired the U.S. commercial rights to FYCOMPA® (perampanel) CIII, a prescription medicine approved in people with epilepsy aged four and older alone or with other medicines to treat partial-onset seizures with or without secondarily generalized seizures and with other medicines to treat primary generalized tonic-clonic seizures for people with epilepsy aged 12 and older. Further, Canada’s national healthcare regulatory agency, Health Canada, has approved the use of FIRDAPSE for the treatment of adult patients in Canada with LEMS. Finally, on July 18, 2023, Catalyst acquired an exclusive license for North America for vamorolone, a promising best-in-class dissociative anti-inflammatory steroid treatment for patients suffering from Duchenne muscular dystrophy. Vamorolone has received FDA Orphan Drug and Fast Track designations and has been granted a PDUFA action date of October 26, 2023.

For more information about Catalyst Pharmaceuticals, Inc., visit the Company’s website at: www.catalystpharma.com. For the Full Prescribing and Safety Information for FIRDAPSE®, please visit www.firdapse.com. For the Full Prescribing Information for FYCOMPA®, please visit www.fycompa.com.

Forward-Looking StatementsThis press release contains forward-looking statements. Forward-looking statements involve known and unknown risks and uncertainties, which may cause Catalyst's actual results in future periods to differ materially from forecasted results. A number of factors, including those factors described in Catalyst's Annual Report on Form 10-K for the fiscal year 2022 and its other filings with the U.S. Securities and Exchange Commission (“SEC”), could adversely affect Catalyst. Copies of Catalyst's filings with the SEC are available from the SEC, may be found on Catalyst's website, or may be obtained upon request from Catalyst. Catalyst does not undertake any obligation to update the information contained herein, which speaks only as of this date.

Important Safety Information: INDICATION FOR FYCOMPAFYCOMPA® (perampanel) is indicated in patients with epilepsy aged 4 years and older for partial-onset seizures (POS) with or without secondarily generalized seizures and adjunctive therapy for patients aged 12 years and older for primary generalized tonic-clonic (PGTC) seizures.

IMPORTANT SAFETY INFORMATION FOR FYCOMPA

WARNING: SERIOUS PSYCHIATRIC AND BEHAVIORAL REACTIONS Serious or life-threatening psychiatric and behavioral adverse reactions including aggression, hostility, irritability, anger, and homicidal ideation and threats have been reported in patients taking FYCOMPA These reactions occurred in patients with and without prior psychiatric history, prior aggressive behavior, or concomitant use of medications associated with hostility and aggression Advise patients and caregivers to contact a healthcare provider immediately if any of these reactions or changes in mood, behavior, or personality that are not typical for the patient are observed while taking FYCOMPA or after discontinuing FYCOMPA Closely monitor patients particularly during the titration period and at higher doses FYCOMPA should be reduced if these symptoms occur and should be discontinued immediately if symptoms are severe or are worsening

SERIOUS PSYCHIATRIC AND BEHAVIORAL REACTIONSIn the partial-onset seizures clinical trials, hostility- and aggression-related adverse reactions occurred in 12% and 20% of patients randomized to receive FYCOMPA at doses of 8 mg and 12 mg per day, respectively, compared to 6% of patients in the placebo group. These effects were dose-related and generally appeared within the first 6 weeks of treatment, although new events continued to be observed through more than 37 weeks. These effects in FYCOMPA-treated patients led to dose reduction, interruption, and discontinuation more frequently than placebo-treated patients. Homicidal ideation and/or threat have also been reported postmarketing in patients treated with FYCOMPA. The combination of alcohol and FYCOMPA significantly worsened mood and increased anger. Patients taking FYCOMPA should avoid the use of alcohol. Patients, their caregivers, and families should be informed that FYCOMPA may increase the risk of psychiatric events. Patients should be monitored during treatment and for at least one month after the last dose of FYCOMPA, and especially when taking higher doses and during the initial few weeks of drug therapy (titration period) or at other times of dose increases. Similar serious psychiatric and behavioral events were observed in the primary generalized tonic-clonic (PGTC) seizure clinical trial.

SUICIDAL BEHAVIOR AND IDEATIONAntiepileptic drugs (AEDs), including FYCOMPA, increase the risk of suicidal thoughts or behavior in patients. Anyone considering prescribing FYCOMPA or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Patients, their caregivers, and families should be informed of the risk and advised to monitor and immediately report the emergence or worsening of depression, suicidal thoughts or behavior, thoughts about self-harm and/or any unusual changes in mood or behavior. Should suicidal thoughts and behavior emerge during treatment, consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.

DIZZINESS AND GAIT DISTURBANCEFYCOMPA caused dose-related increases in events related to dizziness and disturbance in gait or coordination. Dizziness and vertigo were reported in 35% and 47% of patients in the partial-onset seizure trials randomized to receive FYCOMPA at doses of 8 mg and 12 mg per day, respectively, compared to 10% of placebo-treated patients. Gait disturbance related events were reported in 12% and 16% of patients in the partial-onset seizure clinical trials randomized to receive FYCOMPA at doses of 8 mg and 12 mg per day, respectively, compared to 2% of placebo-treated patients. These adverse reactions occurred mostly during the titration phase. These adverse reactions were also observed in the PGTC seizure clinical trial.

SOMNOLENCE AND FATIGUEFYCOMPA caused dose-dependent increases in somnolence and fatigue-related events. Somnolence was reported in 16% and 18% of patients in the partial-onset seizure trials randomized to receive FYCOMPA at doses of 8 mg and 12 mg per day, respectively, compared to 7% of placebo-treated patients. Fatigue-related events were reported in 12% and 15% of patients in the partial-onset seizure trials randomized to receive FYCOMPA at doses of 8 mg and 12 mg per day, respectively, compared to 5% of placebo-treated patients. These adverse reactions occurred mostly during the titration phase. These adverse reactions were also observed in the PGTC seizure clinical trial. Patients should be advised against engaging in hazardous activities requiring mental alertness, such as operating motor vehicles or dangerous machinery, until the effect of FYCOMPA is known. Patients should be carefully observed for signs of central nervous system (CNS) depression when FYCOMPA is used with other drugs with sedative properties because of potential additive effects.

FALLSFalls were reported in 5% and 10% of patients in the partial-onset seizure clinical trials randomized to receive FYCOMPA at doses of 8 mg and 12 mg per day, respectively, compared to 3% of placebo-treated patients.

DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS)DRESS, also known as multiorgan hypersensitivity, has been reported in patients taking AEDs, including FYCOMPA. DRESS may be fatal or life-threatening. DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling, in association with other organ system involvement. If signs or symptoms are present, immediately evaluate the patient and discontinue FYCOMPA if an alternative etiology for signs or symptoms cannot be established.

WITHDRAWAL OF AEDsA gradual withdrawal is generally recommended with AEDs to minimize the potential of increased seizure frequency, but if withdrawal is a response to adverse events, prompt withdrawal can be considered.

MOST COMMON ADVERSE REACTIONSThe most common adverse reactions in patients aged 12 years and older receiving FYCOMPA (≥5% and ≥1% higher than placebo) include dizziness, somnolence, fatigue, irritability, falls, nausea, weight gain, vertigo, ataxia, headache, vomiting, contusion, abdominal pain, and anxiety. Adverse reactions in patients aged 4 to <12 years were generally similar to patients aged 12 years and older.

DRUG INTERACTIONSFYCOMPA may decrease the efficacy of contraceptives containing levonorgestrel. Plasma levels of perampanel were decreased when administered with known moderate and strong CYP3A4 inducers, including, carbamazepine, phenytoin, or oxcarbazepine. Multiple dosing of FYCOMPA 12 mg per day enhanced the effects of alcohol on vigilance and alertness, and increased levels of anger, confusion, and depression. These effects may also be seen when FYCOMPA is used in combination with other CNS depressants.

PREGNANCY AND LACTATIONPhysicians are advised to recommend that pregnant patients taking FYCOMPA enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. Caution should be exercised when FYCOMPA is administered to pregnant or nursing women as there are no adequate data on the developmental risk associated with use in pregnant women, and no data on the presence of perampanel in human milk, the effects on the breastfed child, or the effects of the drug on milk production.

HEPATIC AND RENAL IMPAIRMENTUse in patients with severe hepatic or severe renal impairment is not recommended. Dosage adjustments are recommended in patients with mild or moderate hepatic impairment. Use with caution in patients with moderate renal impairment.

DRUG ABUSE AND DEPENDENCEFYCOMPA is a Schedule III controlled substance and has the potential to be abused and lead to drug dependence and withdrawal symptoms including anxiety, nervousness, irritability, fatigue, asthenia, mood swings, and insomnia.

Please see the full Prescribing Information, including Boxed WARNING.

Source: Catalyst Pharmaceuticals, Inc.

Investor Contact
Mary Coleman
Catalyst Pharmaceuticals, Inc.
(305) 420-3200
mcoleman@catalystpharma.com

Media Contact
David Schull
Russo Partners
(858) 717-2310
david.schull@russopartnersllc.com