Gossamer Bio submits first NDA, for seralutinib in pulmonary arterial hypertension

Gossamer Bio, Inc. disclosed in an 8-K dated September 23, 2026 that it submitted a New Drug Application to the U.S. Food and Drug Administration in September 2026 for seralutinib for the treatment of pulmonary arterial hypertension.¹ The filing marks the company's first NDA submission.¹

The NDA rests on the company's Phase 3 PROSERA Study as one adequate and well-controlled clinical investigation, along with confirmatory evidence from the Phase 2 TORREY Study and supportive analyses.¹

The submission followed earlier regulatory contact. Gossamer held a Pre-NDA Type B meeting with the FDA in June 2026, and the agency's official written minutes described the statistical significance and treatment effect magnitude seen in PROSERA as review issues rather than filing issues, while also giving feedback on the format and content of the planned submission.¹

Looking ahead, the FDA will decide whether to accept the NDA for filing after its initial review, which the company expects could happen later in 2026.¹ Whether the individual elements of the application, including efficacy and safety evidence, are acceptable will be determined by the FDA during its substantive review of the full NDA.¹

Gossamer flagged several risks tied to the process, noting that the FDA may ultimately determine the NDA does not qualify for filing or may decline to accept or approve it, and that the agency could find the overall benefit-risk profile of seralutinib unfavorable.¹ The company also said its future performance depends entirely on seralutinib's success, according to the filing. The report was signed by Bryan Giraudo, Gossamer's Chief Financial Officer and Chief Operating Officer.