Gossamer Bio, Inc., a clinical-stage biopharmaceutical company focused on pulmonary hypertension, has submitted a New Drug Application (NDA) to the US Food and Drug Administration (FDA) for seralutinib for the treatment of Pulmonary Arterial Hypertension (PAH).

The company submitted the NDA in September 2026, marking its first NDA submission. Seralutinib is being developed for PAH as well as pulmonary hypertension associated with interstitial lung disease (PH-ILD).

The NDA is supported by the Phase 3 PROSERA study as one adequate and well-controlled clinical investigation, along with confirmatory evidence from the Phase 2 TORREY study and additional supportive analyses.

The submission follows Gossamer Bio's Pre-NDA Type B meeting with the FDA in June 2026. According to the company, the FDA's official written meeting minutes characterised the statistical significance and magnitude of the treatment effect observed in PROSERA as review issues rather than filing issues. The agency also provided feedback on the format and content of the planned NDA submission.

Faheem Hasnain, Chairman, Co-Founder and chief executive officer of Gossamer Bio, said the submission represents a significant milestone for the company and for patients living with PAH. He also acknowledged the patients, families, investigators, site staff and employees involved in the PROSERA and TORREY studies.

Caryn Peterson, chief development officer of Gossamer Bio, said the NDA reflects work across clinical development, biostatistics, regulatory affairs, manufacturing, quality and other functions. She added that the submission brings the company closer to potentially making seralutinib available as a new treatment option for patients with PAH.

The FDA will conduct an initial review to determine whether the NDA is acceptable for filing. Gossamer Bio expects this determination could occur later in 2026.

The FDA will assess the individual components of the application, including the efficacy and safety evidence, as part of its review of the complete NDA.

Gossamer Bio is focused on the development and commercialisation of seralutinib for PAH and PH-ILD. The company aims to advance treatments for pulmonary hypertension and address the needs of patients living with the disease.