$WINT Successful Completion of Second and Final AEROSURF Phase 2b

DSMB Recommends Continued Enrollment in AEROSURF Phase 2b Clinical Trial Without Modifications- -Company Remains on Track to Release Phase 2b Results Mid-Year 2017

WARRINGTON, Pa., April 11, 2017 — Windtree Therapeutics, Inc. (Nasdaq: WINT), a biotechnology company focused on developing aerosolized KL4 surfactant therapies for respiratory diseases, today announced that the AEROSURF® (lucinactant for inhalation) phase 2b independent Data Safety Monitoring Board (DSMB) has completed its second and final interim safety review and has recommended continuing the trial without modification. The final DSMB interim review was convened following achievement in mid-March 2017 of a pre-specified patient enrollment milestone.  In addition, the Company reaffirms its plan to announce top-line results from the AEROSURF phase 2b clinical trial in mid-year 2017.

“We are very encouraged by the AEROSURF safety and tolerability profile to date and by the progress we have made with patient enrollment in this trial,” said Steve Simonson, M.D., Senior Vice President and Chief Development Officer of Windtree Therapeutics.  “We believe that AEROSURF, if successful, has the potential to transform the treatment of RDS in premature infants. We look forward to completing this clinical trial and sharing top-line results in mid-2017.”

AEROSURF is a novel, investigational drug/device combination product that combines the Company’s proprietary KL4 surfactant and aerosolization technologies.  AEROSURF is being developed to potentially reduce the need for endotracheal intubation and mechanical ventilation in the treatment of premature infants with respiratory distress syndrome (RDS).  The AEROSURF phase 2b clinical trial is a multicenter, randomized, controlled study with masked treatment assignment in up to 240 premature infants receiving nasal continuous positive airway pressure (nCPAP) for RDS, and is designed to evaluate aerosolized KL4 surfactant administered to premature infants 28 to 32 week gestational age in two dose groups (25 and 50 minutes), with up to two potential repeat doses, compared to infants receiving nCPAP alone. The key objectives of this trial are to:

• evaluate efficacy by: (i) incidence of nCPAP failure, (ii) time to nCPAP failure (defined as the need for intubation and delayed surfactant therapy), and (iii) physiological parameters indicating the effectiveness of lung function;
• define the dose regimen(s) for the planned phase 3 clinical program
• provide an estimation of the expected efficacy margin of AEROSURF treatment; and
• further characterize the AEROSURF safety profile

The trial is being conducted in approximately 50 clinical sites in North America, Europe and Latin America.

About Windtree Therapeutics

Windtree Therapeutics, Inc. is a clinical-stage biotechnology company focused on developing novel surfactant therapies for respiratory diseases and other potential applications. Windtree’s proprietary technology platform includes a synthetic, peptide-containing surfactant (KL4 surfactant) that is structurally similar to endogenous pulmonary surfactant and novel drug-delivery technologies being developed to enable noninvasive administration of aerosolized KL4 surfactant. Windtree is focused initially on improving the management of respiratory distress syndrome (RDS) in premature infants and believes that its proprietary technology may make it possible, over time, to develop a pipeline of KL4 surfactant product candidates to address a variety of respiratory diseases for which there are few or no approved therapies.

For more information, please visit the Company’s website at www.windtreetx.com.

Forward-Looking Statements

To the extent that statements in this press release are not strictly historical, all such statements are forward-looking, and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.  These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from the statements made.    Examples of such risks and uncertainties include: the risk that the Company is a development company with limited resources and no operating revenues and its ability to continue as a going concern in the near term is highly dependent upon obtaining results from the AEROSURF phase 2b clinical trial in mid-2017 that are sufficient to support a strategic or financing transaction; risks affecting the Company’s ability to raise capital, including pursuant to its universal shelf registration statement, which permits only limited primary offerings and expires in June 2017, a pending delisting notice from The Nasdaq Market, a potential shortage of available shares of common stock, and a complex capital structure; risks affecting the timing of the Company’s planned clinical trials, which may involve time-consuming and expensive clinical trials and be subject to potentially significant delays or regulatory holds, or fail, and its ability successfully to complete its development programs, secure regulatory approval of its product candidates in the U.S. and in markets outside the U.S.; risks related to development of the aerosol delivery systems (ADS) and related components; risks related to the manufacture of drug products, drug substances, ADS and other materials on a timely basis and in sufficient amounts; risks relating to rigorous regulatory requirements of the U.S. Food and Drug Administration or other regulatory authorities that may require significant additional activities, or may not accept or may withhold or delay consideration of applications, or may not approve or may limit approval of Windtree’s products; and other risks and uncertainties described in Windtree’s filings with the Securities and Exchange Commission including the most recent reports on Forms 10-K, 10-Q and 8-K, and any amendments thereto.