SHAREHOLDER ALERT: Levi & Korsinsky, LLP Notifies Investors It Has Filed a Complaint to Recover Losses Suffered by Purchasers of Gossamer Bio, Inc. Securities and Sets a Lead Plaintiff Deadline of June 1, 2026

SHAREHOLDER ALERT: Levi & Korsinsky, LLP Notifies Investors It Has Filed a Complaint to Recover Losses Suffered by Purchasers of Gossamer Bio, Inc. Securities and Sets a Lead Plaintiff Deadline of June 1, 2026 NEW YORK, March 31, 2026 (GLOBE NEWSWIRE) -- The following statement is being issued by Levi & Korsinsky, LLP:

To: All persons or entities who purchased or otherwise acquired securities of Gossamer Bio, Inc. (“Gossamer” or the “Company”) (NASDAQ: GOSS) between June 16, 2025, and February 20, 2026, inclusive. You are hereby notified that the class action lawsuit Daniel Kinnamon v. Gossamer Bio, Inc., et al. (Case No. 3:26-cv-02016) has been commenced in the United States District Court for the Southern District of California. To get more information go to:

https://zlk.com/pslra-1/gossamer-bio-inc-lawsuit-submission-form

or contact Joseph E. Levi, Esq. either via email at jlevi@levikorsinsky.com or by telephone at (212) 363-7500. There is no cost or obligation to you.

According to the complaint, defendants provided overwhelmingly positive statements to investors while, at the same time, disseminating false and misleading statements and/or concealing material adverse facts concerning the study design for the Company’s Phase 3 PROSERA study, particularly, controlling for the placebo response at the Latin American testing sites.

On February 23, 2026, Gossamer published a press release and hosted a Special Call announcing topline results for its Phase 3 PROSERA study, which failed to meet the primary endpoint of improved six-minute walk distance (6MWD) at Week 24, with a +13.3 meter placebo-adjusted gain (p-0.0320) failing to meet the required 0.025 alpha threshold. Gossamer attributed this miss to patients at Latin American sites performing particularly well on placebo due to enrollment of a heavily-treated lower-risk population.

Following this news, the price of Gossamer’s common stock declined from a closing market price of $2.13 per share on February 20, 2026 to $0.42 per share on February 23, 2025, a decline of over 80% in the span of just a single day.

“Our firm is committed to ensuring that investors receive full compensation for losses caused by corporate misrepresentations,” said Joseph E. Levi, a partner at Levi & Korsinsky. “We encourage GOSS shareholders to step forward before the June 1, 2026 deadline so we can pursue justice on their behalf.”

If you suffered a loss in GOSS securities, you have until June 1, 2026 to request that the Court appoint you as lead plaintiff. Your ability to share in any recovery doesn’t require that you serve as a lead plaintiff.

WHY LEVI & KORSINSKY: Over the past 20 years, the team at Levi & Korsinsky has secured hundreds of millions of dollars for aggrieved shareholders and built a track record of winning high-stakes cases. Our firm has extensive expertise representing investors in complex securities litigation and a team of over 70 employees to serve our clients. For seven years in a row, Levi & Korsinsky has ranked in ISS Securities Class Action Services’ Top 50 Report as one of the top securities litigation firms in the United States.

CONTACT:

Levi & Korsinsky, LLP

Joseph E. Levi, Esq.

Ed Korsinsky, Esq.

33 Whitehall Street, 27th Floor

New York, NY 10004

jlevi@levikorsinsky.com

Tel: (212) 363-7500

Fax: (212) 363-7171