Key Takeaways:
The Schall Law Firm has filed a class-action lawsuit against Gossamer Bio, Inc. (NASDAQ: GOSS), accusing the biotechnology company of making false and misleading statements to investors regarding a key clinical trial.
The lawsuit, filed on behalf of investors who purchased securities between June 16, 2025, and February 20, 2026, centers on the company’s Phase 3 PROSERA study for its pulmonary arterial hypertension (PAH) drug candidate, seralutinib.
According to the complaint, Gossamer failed to disclose that patients at its Latin American trial sites were heavily-treated and lower-risk, which resulted in them performing unusually well on the placebo. This allegedly skewed the results, causing the PROSERA study to miss its primary endpoint of improved six-minute walk distance at week 24, a critical measure of the drug's efficacy.
The failure to meet this endpoint, announced in February 2026, allegedly caused significant losses for investors who had purchased stock based on the company's prior positive statements about the trial's prospects. The lawsuit seeks to recover these damages. The deadline for investors to file a lead plaintiff motion is June 1, 2026.
The allegations put Gossamer's clinical trial disclosures and management of its global studies under scrutiny. Investors will be watching for the company's formal response to the lawsuit and the court's appointment of a lead plaintiff after the June 1 deadline.
This article is for informational purposes only and does not constitute investment advice.
