Filed Pursuant to Rule 424(b)(3)
Registration No. 333-278989
1,918,140 Shares of Common Stock Offered by the Selling Stockholders
This prospectus relates to the offer and resale, from time to time, by the selling stockholders named under the heading Selling Stockholders in
this prospectus, or their assigns (the Selling Stockholders), of 1,918,140 shares (the Shares) of the Companys common stock, par value $0.01 per share (the Common Stock), which consist of (i)
1,806,427 shares of Common Stock, (ii) 77,641 shares of Common Stock (the PIPE Warrant Shares and together with the 1,806,427 Shares, the PIPE Securities) issuable upon the exercise of pre-funded warrants (the
PIPE Warrants) held by certain Selling Stockholders, and (iii) 34,072 shares of Common Stock that were issued upon the exercise of pre-funded warrants to purchase Common Stock (the Avenue Amendment Warrants) previously
issued by the Company pursuant to an amendment to the Loan and Security Agreement dated as of March 31, 2023 (the Amended Avenue Agreement) with Avenue Venture Opportunities Fund, L.P. (Avenue), all of which were
exercised. We are registering the offer and sale of the PIPE Securities to satisfy the registration rights they were granted pursuant to a registration rights agreement entered into on March 14, 2024 in connection with the securities purchase
agreement entered into on March 14, 2024. We are registering the offer and sale of the shares of Common Stock outstanding upon exercise of the Avenue Amendment Warrants to satisfy the registration rights that were granted pursuant to the
Amended Avenue Agreement. While we will not receive any proceeds from the sale of the Shares by the Selling Stockholders, we will receive proceeds from the exercise of any PIPE Warrants for cash.
Our registration of the Shares covered by this prospectus does not mean that the Selling Stockholders will offer or sell any such Shares. The Selling
Stockholders may sell Shares covered by this prospectus in a number of different ways and at varying prices. For additional information on the possible methods of sale that may be used by the Selling Stockholders, you should refer to the section of
this prospectus entitled Plan of Distribution. The Selling Stockholders may, individually but not severally, be deemed to be an underwriter within the meaning of the Securities Act of 1933, as amended (the Securities
Act), of the Shares that they are offering pursuant to this prospectus. The Selling Stockholders will bear all commissions and discounts, if any, attributable to their respective sales of Common Stock hereunder. We will bear all costs,
expenses and fees in connection with the registration of the Common Stock. We will not be paying any underwriting discounts or commissions in this offering.
A prospectus supplement may add, update, or change information contained in this prospectus. You should carefully read this prospectus, any applicable
prospectus supplement, and the information incorporated by reference in this prospectus and any applicable prospectus supplement before you make your investment decision.
Our Common Stock is traded on The Nasdaq Capital Market under the symbol DCTH. On May 9, 2024, the closing price for our Common Stock, as reported
on The Nasdaq Capital Market, was $5.56 per share. Our common stock outstanding as of April 24, 2024 was 27,784,384. Our principal executive offices are located at 566 Queensbury Avenue, Queensbury, NY 12804.
Investing in these securities involves certain risks. See Risk Factors on page 6 of this prospectus and in
the documents incorporated by reference in this prospectus for a discussion of the factors you should carefully consider before deciding to purchase these securities.
Neither the SEC nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or
complete. Any representation to the contrary is a criminal offense.
The date of
this prospectus is May 9, 2024