Citius Oncology Inc美股招股说明书(2025-12-10版)

Prospectus Supplement(to prospectus dated September 4, 2025) 1,284,404 Shares of Common Stock Pursuant to this prospectus supplement and the accompanying prospectus, we are offering 1,284,404 shares of our commonstock, $0.0001 par value per share, to a single institutional investor, at an offering price of $1.09 per share of common stock. In a concurrent private placement, we are also selling to such institutional investor warrants to purchase up to 1,284,404shares of common stock (the “Common Warrants), with an exercise price of $1.09 per share of our common stock, which areexercisable upon Stockholder Approval (as defined in the Common Warrant), and with a term of five years from the date ofStockholder Approval. The Common Warrants are being offered pursuant to the exemption provided in Section 4(a)(2) under theSecurities Act of 1933, as amended (the “Securities Act”), and/or Rule 506(b) promulgated thereunder, and they are not being offeredpursuant to this prospectus supplement and the accompanying prospectus. On December 8, 2025, we also entered into a securities purchase agreement with such institutional investor to issue in aconcurrent private placement (the “Private Placement”) pre-funded warrants to purchase up to 15,229,358 shares of common stock(the “Pre-funded Warrants”) and 15,229,358 Common Warrants, at a combined price of $1.0899 per Pre-funded Warrant andaccompanying Common Warrant. The exercise price of each Pre-funded Warrant is $0.0001 per share. The Pre-funded Warrants andCommon Warrants are being offered pursuant to the exemption provided in Section 4(a)(2) under the Securities Act, and/or Rule506(b) promulgated thereunder, and they are not being offered pursuant to this prospectus supplement and the accompanyingprospectus. The securities offered in the concurrent Private Placement are more fully described in the section of this prospectusentitled “Private Placement Transaction.” Our common stock is traded on Nasdaq under the symbol “CTOR”. The last reported sale price of our common stock onNasdaq on December 8, 2025 was $1.09 per share. We have engaged H.C. Wainwright & Co., LLC (the “placement agent”) to act as our placement agent in connection with thisoffering. The placement agent has agreed to use their reasonable best efforts to place the securities offered by this prospectussupplement. We have agreed to pay the placement agent the placement agent fees set forth in the table below. The placement agent isnot purchasing or selling any of the securities offered pursuant to this prospectus supplement. The securities will be sold directly to thepurchasers pursuant to the securities purchase agreement. See “Plan of Distribution” in this prospectus supplement for moreinformation. Proceeds to us (before expenses)(2) (1)We have agreed to pay the placement agent a cash fee equal to 7.0% of the gross proceeds raised in this offering. We also haveagreed to reimburse the placement agent for certain of its offering-related expenses. In addition, we have agreed to issue theplacement agent or its designees warrants to purchase up to 89,908 shares of common stock at an exercise price of $1.3625 pershare. We refer to these warrants in this prospectus supplement as the “Placement Agent Warrants.” See “Plan of Distribution” fora complete description of the compensation to be received by the placement agent.(2)The amount of offering proceeds to us presented in this table does not give effect to any exercise of the Private Placement Pre- funded Warrants, Common Warrants or Placement Agent Warrants. The aggregate market value of our outstanding common stock held by non-affiliates as of the date of this prospectus is$31,222,252, based on 17,442,599 shares of outstanding common stock held by non-affiliates as of December 8, 2025, and a per shareprice of $1.79 the closing sale price of our common stock on October 21, 2025 (a date within 60 days of the date hereof). Pursuant toGeneral Instruction I.B.6 of Form S-3, in no event will we sell the securities described in this prospectus in a primary public offeringwith a value exceeding more than one-third of the aggregate market value of our common stock held by non-affiliates in the twelve-month period prior to the date of the sale of any such securities, so long as the aggregate market value of our outstanding commonstock held by non-affiliates remains below $75.0 million. During the 12 calendar months prior to this offering, we have sold $9 millionof securities pursuant to General Instruction I.B.6 of Form S-3. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-5 of this prospectussupplement and on page 3 of the accompanying prospectus, as well as the documents incorporated by reference into thisprospectus supplement and accompanying prospectus, to read about factors you should consider before investing in oursecurities. We anticipate that delivery of the shares of common stock against payment there