Fennec Pharmaceuticals Inc美股招股说明书(2025-11-17版)

FENNEC PHARMACEUTICALS INC. Common Shares We are offering 4,666,667 of our common shares, no par value per share, pursuant to this prospectus supplement and theaccompanying prospectus.Our common shares are listed on The Nasdaq Capital Market under the symbol “FENC” and on the Toronto Stock Exchange under the symbol “FRX.” On November14, 2025, the last reported sale price of our common shares on The NasdaqCapital Market was $7.69 per share. Investing in our securities involves a high degree of risk. You should carefully review and consider the risks anduncertainties described under the heading “Risk Factors” beginning on pageS-4of this prospectus supplement and in therelated sections noted in the accompanying prospectus, and in the documents incorporated by reference herein and therein.Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation tothe contrary is a criminal offense. (1)See “Underwriting” for additional information regarding compensation payable to the underwriters.We have granted a 30-day option to the underwriters to purchase up to additional common shares. Delivery of the shares of common stock is expected to be made on or about November 17, 2025. Concurrently with the offering, we intend to complete a non-brokered offering in the provinces of Canada (the “ConcurrentLIFE Offering”) of common shares on the same terms as this offering for aggregate gross proceeds of up to $5,025,000 withcertain of our existing institutional shareholders. The Concurrent LIFE Offering has been structured under Canadian securitieslaws pursuant to the listed issuer financing exemption from Canadian prospectus requirements under Part5A of NationalInstrument 45-106 — Prospectus Exemptions. This prospectus supplement does not register or qualify for distribution thecommon shares to be offered in the Concurrent LIFE Offering. The Company expects to register any common shares issued inthe Concurrent LIFE Offering, if any, under the Securities Act in a separate prospectus supplement. We will enter into asubscription agreement with each such investor setting out the detailed terms of the Concurrent LIFE Offering. We anticipateusing the net proceeds of the Concurrent LIFE Offering for working capital and general corporate purposes. The ConcurrentLIFE Offering is expected to close at the same time or shortly after this offering. We cannot assure you that the Concurrent LIFEOffering will be completed or, if completed, on what terms it will be completed. See “Recent Developments — Concurrent LIFEOffering” on page S-2 of this prospectus supplement for more information. If the Concurrent LIFE Offering is completed, it willresult in dilution to investors participating in this offering. See “Risk Factors — Risks Related to this Offering” on page S-4. Joint Book-Running Managers Piper Sandler Craig-Hallum Lead ManagerH.C. Wainwright & Co.Co-ManagerStephens Inc.November 13, 2025 TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTS-iiNOTE REGARDING FORWARD-LOOKING STATEMENTSS-iiiSUMMARYS-1THE OFFERINGS-3RISK FACTORSS-4USE OF PROCEEDSS-5DIVIDEND POLICYS-6CAPITALIZATIONS-7DILUTIONS-9UNDERWRITINGS-10NOTICE TO INVESTORSS-14MATERIAL CANADIAN AND UNITED STATES TAX CONSEQUENCES OF THIS OFFERINGS-15LEGAL MATTERSS-21EXPERTSS-22WHERE YOU CAN FIND MORE INFORMATIONS-23INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCES-24ProspectusPageFORWARD LOOKING STATEMENTS1FENNEC PHARMACEUTICALS INC.2WHERE YOU CAN FIND MORE INFORMATION3INCORPORATION BY REFERENCE4RISK FACTORS5USE OF PROCEEDS6DESCRIPTION OF CAPITAL STOCK7CERTAIN ERISA MATTERS9PLAN OF DISTRIBUTION10LEGAL MATTERS12EXPERTS13 ABOUT THIS PROSPECTUS SUPPLEMENT This document contains two parts. The first part is this prospectus supplement, which describes theterms of this offering and also adds to and updates information contained in the accompanying prospectusandthe documents incorporated by reference in this prospectus supplement and the accompanyingprospectus.The second part,the accompanying prospectus dated December 15,2023,including thedocuments incorporated by reference therein, provides more general information, some of which may notapply to this offering. Generally, when we refer to this prospectus, we are referring to both parts of thisdocument combined. To the extent there is a conflict between the information contained in this prospectussupplement, on the one hand, and the information contained in the accompanying prospectus or in anydocument incorporated by reference that was filed with the Securities and Exchange Commission (the“SEC”) before the date of this prospectus supplement, on the other hand, you should rely on the informationin this prospectus supplement. If any statement in one of these documents is inconsistent with a statement inanotherdocument having