GOSS: Announces Topline Results for Phase 3 PROSERA Trial -- LEVI & KORSINSKY, LLP

Gossamer Bio Provided Forward-Looking Trial Guidance While Omitting the Heightened Statistical Threshold That Made a Miss More Likely

NEW YORK, April 1, 2026 /PRNewswire/ -- Gossamer Bio, Inc. (NASDAQ: GOSS) lost more than 60% of its value after the Company's Phase 3 PROSERA trial of seralutinib missed its primary endpoint. In May 2025, CEO Faheem Hasnain told investors on the Q1 2025 earnings call: "We anticipate announcing top-line results in February 2026" -- guidance that set expectations for a meaningful readout. Shareholders who lost money on GOSS are encouraged to submit their information here . You may also contact Joseph E. Levi, Esq. via email at jlevi@levikorsinsky.com  or by telephone at (212) 363-7500.

The forward guidance created a specific expectation: results in February 2026, with management expressing they were "more optimistic than ever about the likelihood of achieving positive results." At the time of that statement on May 15, 2025, the Company did not disclose to investors that the PROSERA study's pre-specified statistical plan required significance at alpha = 0.025 -- a threshold twice as stringent as the conventional 0.05 level used in many pivotal trials. The actual p-value came in at 0.032, which would have cleared a 0.05 bar but failed the 0.025 requirement.

The gap between the guidance tone and the undisclosed statistical hurdle is the focus of this investigation. Investors who relied on management's forward-looking statements and timing guidance had no way to assess the elevated risk of a technical miss. Those who purchased GOSS shares and suffered a loss may click here to discuss their legal rights . You may also contact Joseph E. Levi, Esq. via email at jlevi@levikorsinsky.com  or by telephone at (212) 363-7500.

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CONTACT:

Levi & Korsinsky, LLP

Joseph E. Levi, Esq.

Ed Korsinsky, Esq.

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jlevi@levikorsinsky.com

Tel: (212) 363-7500

Fax: (212) 363-7171

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