Gossamer Bio Investors Face June 1 Deadline in Securities Class Action

Investors have until June 1 to ask the court to serve as lead plaintiff in the case.

Overview

Investor law firms report a class action is on file and urge Gossamer shareholders to seek lead‑plaintiff status by June 1, 2026.
The case covers purchases between June 16, 2025 and February 20, 2026 and claims the company misled investors about the PROSERA trial design.
Filings center on controls for the placebo response at Latin American trial sites that plaintiffs say were inadequate.
Gossamer disclosed on February 23, 2026 that the study missed its main goal on six‑minute walk distance, with a 13.3‑meter placebo‑adjusted gain that fell short of the 0.025 significance level at p=0.0320.
Shares dropped more than 80% to $0.42 that day, and no class has been certified or liability established.