Gossamer Bio targets September NDA for seralutinib and reacquires global rights

• Gossamer Bio (NASDAQ:GOSS) plans to submit a New Drug Application (NDA) for seralutinib in pulmonary arterial hypertension (PAH) in September 2026.
• The company has reacquired full worldwide development and commercial rights to seralutinib following the termination of its collaboration with Chiesi.
• Stockholders approved a convertible note exchange that reduces corporate debt by $115.9 million and authorized a reverse stock split to maintain Nasdaq compliance.

Gossamer Bio (NASDAQ:GOSS) has announced a series of strategic and regulatory updates, highlighted by plans to submit a New Drug Application (NDA) for its lead candidate, seralutinib, in September 2026.

The clinical-stage biopharmaceutical company is developing the inhaled inhibitor for the treatment of pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD).

Following a productive Pre-NDA Type B meeting with the U.S. Food and Drug Administration (FDA) in mid-June 2026, the agency indicated that the statistical significance and treatment effect magnitude observed in the Phase 3 PROSERA study are review issues rather than filing issues.

Consequently, Gossamer intends to submit an NDA supported by the PROSERA trial and confirmatory evidence from the Phase 2 TORREY study.

If accepted for filing, seralutinib could see an FDA approval decision by the third quarter of 2027.

In a major strategic shift, Gossamer Bio has agreed to terminate its collaboration and license agreement with Chiesi, reacquiring the worldwide development and commercial rights to seralutinib.

Under the termination terms, Chiesi will make a one-time $5 million payment to Gossamer.

In exchange, Chiesi will be entitled to a capped royalty on global net sales and specified regulatory and commercial milestone payments.

This consolidation gives Gossamer full operational control over the asset without requiring an upfront cash payment from the company.

Reflecting these updates, Gossamer Bio shares traded near $0.14.

On the corporate front, the company held a special meeting on July 14, 2026, where stockholders approved proposals related to a convertible note exchange.

The transaction exchanged approximately $181.1 million of 2027 notes for $65.2 million of new 7.50% convertible notes due in 2030, effectively reducing the company's debt by $115.9 million.

Furthermore, stockholders authorized the Board to implement a reverse stock split, expected to occur in or after the third quarter of 2026, to ensure compliance with Nasdaq’s minimum bid price requirement.

Gossamer Bio also reported a preliminary cash, cash equivalents, and marketable securities balance of approximately $57 million as of June 30, 2026.