Windtree Therapeutics Inc.'s istaroxime improved cardiac function in patients with acute heart failure compared to placebo during a mid-stage study.

The Warrington, Pa.-based biotechnology company evaluated 24-hour infusions of 0.5 and 1 micrograms per kilogram per minute doses for safety and efficacy in 120 patients with acute heart failure. The disease is characterized by the sudden appearance or abrupt worsening of heart failure symptoms.

Patients taking the drug saw cardiac function improvements in both dose arms of the trial, meeting the study's main goal. A secondary goal of decreasing stroke volume was also met. Windtree said that common complications of existing acute heart failure treatments were not observed in the trial, including instances of irregular heartbeats. The drug significantly improved blood pressure during treatment, contributing to improved kidney function.

Windtree said istaroxime was well-tolerated among patients: 10% of the participants in the low-dose arm of the trial and 18% in the high-dose arm experienced cardiovascular-related adverse events. In comparison, 23% of the patients in the placebo group reported these adverse events.

Patients taking istaroxime did, however, see a slightly elevated occurrence of heart failure, at 5% in the low dose arm and 8% in the high dose, compared to 3% with placebo. The most common reported adverse event was pain at the infusion site and gastrointestinal events.

Windtree Chief Medical Officer Steve Simonson said the company looks forward to advancing istaroxime's development based on the results, which were presented during a session at the European Society of Cardiology Heart Failure Congress, according to a May 30 press release.