Windtree Announces Istaroxime Phase 2 Cardiogenic Shock Study Hits Enrollment Target for Planned Interim Analysis

The SEISMiC C Study is the third study in the istaroxime cardiogenic shock development program - SEISMiC C is studying more severely ill SCAI Stage C cardiogenic shock patients

Windtree has previously reported two positive early cardiogenic shock Phase 2 studies in SCAI Stage B patients

The SEISMiC C interim analysis will provide a preliminary assessment of istaroxime safety in treating more severe cardiogenic shock patients who may be receiving standard of care with inotropes and vasopressors

SCAI Stage C is a sicker patient population than early cardiogenic shock and has high mortality despite currently used drug treatments

WARRINGTON, Pa., June 30, 2025 (GLOBE NEWSWIRE) --  Windtree Therapeutics, Inc. (“Windtree” or the “Company”) (NasdaqCM: WINT), a diversified company focused on revenue generation in multiple growing industries is pleased to announce that the Company has reached the planned enrollment of 20 patients for the interim analysis in its istaroxime Phase 2 SEISMiC C study in SCAI Stage C cardiogenic shock patients.

The SEISMiC C Study is a global trial including sites in the U.S., Europe and Latin America. It is a placebo-controlled, double-blinded study with istaroxime being added to current standard of care, including inotropes or vasopressors. The primary endpoint of the study is the systolic blood pressure (“SBP”) profile over the first six hours of treatment when istaroxime is used with this background therapy in more severe patients. Other key study measurements include various measures of cardiac function, SBP changes at specified timepoints, the vasopressor-inotrope score, avoidance of progression to more severe shock in addition to other clinical assessments. The interim analysis will be primarily looking at preliminary safety and tolerability in this setting and an assessment of preliminary efficacy signals to appropriately size the remainder of the SEISMiC C trial. A statistically significant efficacy signal is not anticipated at the interim analysis.

The Company believes that this SCAI stage C study will be valuable for Phase 3 readiness of istaroxime in cardiogenic shock because these patients will be an important population for the target indication in the Phase 3 study. The Company also expects these data to be useful in its planned end of Phase 2 meeting with FDA.

“We are pleased to reach the study enrollment needed for the interim analysis in SCAI Stage C patients with cardiogenic shock,” said Steve Simonson, M.D., Chief Medical Officer of Windtree. “As we make progress toward Phase 3 readiness for istaroxime, we believe the profile of istaroxime is being differentiated from currently available drugs used for this condition.”

“The Company continues to make progress towards its ultimate goal of assisting in bringing this drug candidate to market,” said Jed Latkin, Chief Executive Officer of Windtree. “The current treatment regime isn’t doing enough to help with this very severe condition, and we hope that as istaroxime advances to Phase 3, a new treatment paradigm will emerge. This interim look is yet another step on that path towards what we hope will be its eventual approval.”

About Istaroxime

Istaroxime is a first-in-class dual-mechanism therapy designed to improve both systolic and diastolic cardiac function. Istaroxime is a positive inotropic agent that increases myocardial contractility through inhibition of Na+/K+- ATPase with a complimentary mechanism that facilitates myocardial relaxation through activation of the SERCA2a calcium pump on the sarcoplasmic reticulum enhancing calcium reuptake from the cytoplasm. Data from multiple Phase 2 studies in patients with early cardiogenic shock or acute decompensated heart failure demonstrate that istaroxime infused intravenously can significantly improve cardiac function and blood pressure without increasing heart rate or the incidence of clinically significant cardiac rhythm disturbances.

About Windtree Therapeutics, Inc.

Windtree Therapeutics, Inc. is a diversified company focused on becoming a revenue generating company in a multitude of growing industries to drive toward overall profitability.

Forward Looking Statements

The Company may, in some cases, use terms such as “predicts,” “believes,” “potential,” “proposed,” “continue,” “estimates,” “anticipates,” “expects,” “plans,” “intends,” “may,” “could,” “might,” “will,” “should” or other words that convey uncertainty of future events or outcomes to identify these forward-looking statements. Such statements are based on information available to the Company as of the date of this press release and are subject to numerous important factors, risks and uncertainties that may cause actual events or results to differ materially from the Company’s current expectations. Examples of such risks and uncertainties include, among other things: the Company’s risks and uncertainties associated with the success and advancement of its product candidates; the Company’s ability to manage costs and execute on its operational and budget plans; risks related to technology transfers to contract manufacturers and manufacturing development activities; delays encountered by the Company, contract manufacturers or suppliers in manufacturing drug products, drug substances, and other materials on a timely basis and in sufficient amounts; risks relating to regulatory requirements; risks related to the size and growth potential of the markets for the Company’s product candidates, and the Company’s ability to service those markets; the Company’s ability to develop sales and marketing capabilities, whether alone or with potential future collaborators; the rate and degree of market acceptance of the Company’s product candidates, if approved; the impacts of political unrest, including as a result of geopolitical tension, and any sanctions, export controls or other restrictive actions that may be imposed by the United States and/or other countries which could have an adverse impact on the Company’s operations, including through disruption in supply chain or access to potential international clinical trial sites. These and other risks are described in the Company’s periodic reports, including its Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, filed with or furnished to the Securities and Exchange Commission and available at . Any forward-looking statements that the Company makes in this press release speak only as of the date of this press release. The Company assumes no obligation to update forward-looking statements whether as a result of new information, future events or otherwise, after the date of this press release.

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Eric Curtis