分子生物技术股份有限公司美股招股说明书（2025-07-11版）

On July 11, 2025, we entered into a certain At The Market Offering Agreement (“ATM Agreement”) with Roth Capital Partners, LLC as sales agent (“Roth”) relating to the sale of shares of our common stock, par value $0.001 per share, offered by thisprospectus supplement and the accompanying prospectus. In accordance with the terms of the ATM Agreement, under this prospectus supplement and the accompanying prospectus, we may offer and sell shares of our common stock having an aggregateoffering price of up to $6.5 million from time to time through or to Roth, acting as our sales agent or principal. “Securities Act”). If authorized by us in writing, Roth may also sell shares of our common stock in negotiated transactions atmarket prices prevailing at the time of sale or at prices related to such prevailing market prices. If we and Roth agree on anymethod of distribution other than sales of shares of our common stock on or through the Nasdaq Capital Market or another existingtrading market in the United States at market prices, we will file a further prospectus supplement providing all information about similar arrangement.Compensation to Roth for sales of common stock sold pursuant to the ATM Agreement will be equal to up to 3.0%of the grossproceeds of any shares of common stock sold under the ATM Agreement, in addition to the reimbursement of certain expenses. Inconnection with the sale of our common stock on our behalf, Roth will be deemed to be an “underwriter” within the meaning ofthe Securities Act and the compensation paid to Roth will be deemed to be underwriting commissions or discounts. We have alsoagreed to provide indemnification and contribution to Roth with respect to certain liabilities, including liabilities under the As of July 10, 2025, the aggregate market value of the voting and non-voting common equity held by non-affiliates, our publicfloat, was approximately $31.5 million, , based on 30,207,494shares of outstanding common stock as of July 10, 2025, of which29,165,169 shares were held by non-affiliates, and at a price of $1.08 per share, the closing sale price of our common stock onMay 12, 2025, which is the highest closing sale price of our common stock on Nasdaq within the prior 60 days of this prospectussupplement. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities in a public primary offering with Investing in our securities involves a high degree of risk. See“Risk Factors”beginning on page S-9 of this prospectussupplement and the risk factors incorporated by reference into this prospectus supplement and the accompanying prospectus.Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these LEGAL MATTERSEXPERTS WHERE YOU CAN FIND MORE INFORMATION PROSPECTUSABOUT THIS PROSPECTUSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION BY REFERENCEABOUT MOLECULIN BIOTECH, INC.RISK FACTORSFORWARD-LOOKING STATEMENTSUSE OF PROCEEDSDESCRIPTION OF COMMON STOCK LEGAL MATTERS securities under the accompanying prospectus we will provide a prospectus supplement that will contain specific information aboutthe terms of that offering, including the price, the amount of securities being offered and the plan of distribution. The shelf This prospectus supplement describes the specific details regarding this offering and may add, update or change informationcontained in the accompanying prospectus and the documents incorporated by reference herein and therein. The accompanyingprospectus provides general information about us and our securities, some of which, such as the section entitled “Plan ofDistribution,” may not apply to this offering. This prospectus supplement and the accompanying prospectus are an offer to sellonly the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. We are not makingoffers to sell or solicitations to buy our common stock in any jurisdiction in which an offer or solicitation is not authorized or inwhich the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer orsolicitation. accompanying prospectus and any free writing prospectus we have authorized for use in connection with this offering include all material information relating to this offering. We have not, authorized anyone to provide you with different or additionalinformation and you must not rely on any unauthorized information or representations. We and Roth take no responsibility for, andcan provide no assurance as to the reliability of, any other information that others may give you. You should assume that theinformation appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference inthis prospectus supplement and the accompanying prospectus and any free writing prospectus we have authorized for use inconnection with this offering is accurate only as of