Gossamer Bio Investors Face June 1 Deadline to Seek Lead Role in Securities Class Action
Plaintiffs allege the company misled the market about placebo handling in its Phase 3 PROSERA trial at Latin American sites.
Overview
- A securities class action has been filed for buyers of Gossamer Bio shares purchased from June 16, 2025 through February 20, 2026.
- Investors who want to serve as lead plaintiff must ask the court by June 1, 2026.
- The complaints say executives promoted the program while hiding study design problems tied to how placebo response was managed at Latin American trial locations.
- One filing claims patients at those sites were lower risk and heavily treated, which left the placebo group performing well and the study missing the six‑minute walk test goal at week 24.
- No class has been certified, so investors are not represented unless they hire a lawyer or the court later appoints class counsel.