Investor Alert: Class Action Filed Against Gossamer Bio, Inc. Amid Significant Stock Decline

Gossamer Bio, Inc. Faces Class Action Lawsuit

Pomerantz LLP recently announced the initiation of a class action lawsuit targeting Gossamer Bio, Inc. (NASDAQ: GOSS), focused on allegations concerning securities fraud and other illicit business conduct. This lawsuit has emerged in light of severe financial repercussions following the company's Phase 3 PROSERA study announcement, which reported disheartening results regarding its treatment for pulmonary arterial hypertension.

Background on Gossamer Bio, Inc.

Gossamer Bio, a biotechnology firm, specializes in innovative therapies for various diseases. The market perception of Gossamer took a significant hit on February 23, 2026, when the company disclosed that its PROSERA study for seralutinib did not meet its primary endpoint, which was to show an improvement in the six-minute walk distance in patients after 24 weeks. The results revealed only a +13.3 meter placebo-adjusted gain, which failed to satisfy the required 0.025 alpha threshold. Such disappointing findings were attributed to an unexpectedly higher performance of the placebo group, raising concerns about the enrollment process.

Financial Impact on Investors

The announcement of the PROSERA study results had an immediate and drastic effect on Gossamer's stock price, causing it to tumble by $1.71 per share, equating to an alarming 80.13% drop. By the close of trading on that day, shares were down to $0.42. The sharp decline prompted investor scrutiny and the filing of the class action lawsuit by Pomerantz LLP. Investors who felt the brunt of financial loss are encouraged to act promptly, as there are critical deadlines approaching for those wishing to join the lawsuit.

Call to Action for Investors

Investors who acquired securities in Gossamer during the class period are urged to make contact with the Pomerantz team. Those interested should reach out to attorney Danielle Peyton directly via email at [email protected] or contact the firm toll-free at 888-4-POMLAW (Ext. 7980). When reaching out, investors are advised to provide their mailing address, phone number, and the number of shares they purchased to facilitate communication and potential participation in the legal process.

Furthermore, June 1, 2026, marks a critical deadline for filing as a Lead Plaintiff in the class action, emphasizing the urgency of taking action. Detailed information regarding the lawsuit can be acquired through the firm's website at Pomerantz.

About Pomerantz LLP

Founded over 85 years ago, Pomerantz LLP stands as one of the leading law firms in the domain of corporate, securities, and antitrust class litigation. The firm was established by Abraham L. Pomerantz, a pioneer in the class action sector, recognized for advocating the rights of investors affected by securities fraud and misconduct. With offices spanning New York, Chicago, Los Angeles, London, Paris, and Tel Aviv, Pomerantz continues to uphold its tradition of delivering robust legal representation to those pursuing justice for financial losses caused by corporate malfeasance.

Investors are reminded that prior legal outcomes do not guarantee similar results in this current action, highlighting the importance of individualized legal assessments.

For more assistance or to raise inquiries regarding your investment in Gossamer Bio, Inc., don’t hesitate to contact Pomerantz LLP today.