windtree therapeutics inc美股招股说明书(2025-11-21版)

WINDTREE THERAPEUTICS, INC.Up to 751,872,888 Shares of Common Stock This prospectus supplement (this “Prospectus Supplement”) amends and supplements the prospectus dated November 13, 2025 (as maybe supplemented or amended from time to time, the “Prospectus”), which forms part of our Registration Statement on Form S-1(Registration Statement No. 333-291056). This Prospectus Supplement is being filed to update and supplement the informationincluded or incorporated by reference in the Prospectus with the information contained in the attached Quarterly Report on Form 10-Q,filed with the Securities and Exchange Commission (the “Securities and Exchange Commission”) on November 19, 2025 (the “Form10-Q”). Accordingly, we have attached the Form 10-Q to this Prospectus Supplement. This Prospectus Supplement updates and supplements the information in the Prospectus and is not complete without, and may not bedelivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This ProspectusSupplement should be read in conjunction with the Prospectus, and if there is any inconsistency between the information in theProspectus and this Prospectus Supplement, you should rely on this Prospectus Supplement. Our common stock is traded on the over-the-counter market (“OTCID”) under the symbol “WINT”. On November 19, 2025, the lastquoted bid price of our common stock as reported on OTCID was $0.05 per share. We are an“emerging growth company”under applicable federal securities laws and will be subject to reduced public companyreporting requirements. Investing in our securities involves a high degree of risk. Before buying any securities, you should carefully read the discussionof the risks of investing in our securities in“Risk Factors”beginning on page 8of the Prospectus. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesecurities to be issued under the Prospectus or determined if the Prospectus is truthful or complete. Any representation to thecontrary is a criminal offense. The date of this Prospectus Supplement is November 21, 2025. Table of Contents UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C. 20549FORM 10-Q QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period endedSeptember 30, 2025 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition periodfrom_____to_____ CommissionFile Number: 001-39290 WINDTREE THERAPEUTICS, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) 2600 Kelly Road, Suite 100Warrington, Pennsylvania(Address of principal executive offices) Registrant’s telephone number, including area code:(215) 488-9300 Securities registered pursuant to Section 12(b) of the Act: Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the SecuritiesExchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file suchreports),and (2) has been subject to such filing requirements for the past 90 days.Yes☒No☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuantto Rule405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrantwas required to submit such files).Yes☒No☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reportingcompany, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reportingcompany,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. Accelerated filer☐ Large accelerated filer☐ Non-accelerated filer☒ Emerging growth company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).Yes☐No☒ Table of Contents PART I - FINANCIAL INFORMATION Item 1.Financial Statements4CONDENSED CONSOLIDATED BALANCE SHEETS4As of September 30, 2025 (unaudited) and December 31, 2024CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited)5For the Three and Nine Months Ended September 30, 2025and 2024CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN MEZZANINE EQUITY ANDSTOCKHOLDERS’ EQUITY (unaudited)For the Three and Nine Months Ended September30, 2025and 20246CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited)8For the NineMonths Ended September 30, 2025and 2024