Gossamer Bio, Inc. filed a current report on Form 8-K on September 23, 2026, announcing that it submitted a New Drug Application to the U.S. Food and Drug Administration for seralutinib for the treatment of pulmonary arterial hypertension.

Key Highlights

  • First NDA submission: Gossamer Bio disclosed that this is the company's first NDA submission.
  • Drug and indication: The NDA covers seralutinib for the treatment of pulmonary arterial hypertension (PAH).
  • Supporting studies: The NDA is supported by the Phase 3 PROSERA Study as one adequate and well-controlled clinical investigation, together with confirmatory evidence from the Phase 2 TORREY Study and supportive analyses.
  • Pre-NDA meeting: The company held a Pre-NDA Type B meeting with the FDA in June 2026, following which the FDA characterized the degree of statistical significance and the magnitude of the treatment effect observed in PROSERA as review issues rather than filing issues.
  • FDA filing decision: According to the filing, the company anticipates the FDA's initial review, which would determine whether to accept the NDA for filing, could occur later this year.

Gossamer Bio Submits First-Ever NDA to FDA for PAH Drug Seralutinib

Gossamer Bio, Inc. (NASDAQ:GOSS), headquartered in San Diego, California, disclosed in an 8-K filed September 23, 2026, that it submitted a New Drug Application to the FDA for seralutinib in September 2026. The company described the submission as its first NDA, targeting pulmonary arterial hypertension, a serious cardiovascular condition.

According to the filing, the NDA package rests on the Phase 3 PROSERA Study as one adequate and well-controlled clinical investigation, supplemented by confirmatory evidence from the Phase 2 TORREY Study and supportive analyses. The submission followed a Pre-NDA Type B meeting with the FDA in June 2026. The filing states that in the FDA's official written meeting minutes from that interaction, the FDA "characterized the degree of statistical significance and the magnitude of the treatment effect observed in PROSERA as review issues rather than filing issues," and provided feedback on the format and content of the planned submission.

The filing notes that the FDA will determine whether to accept the NDA for filing following its initial review, which the company anticipates could occur later this year. The company also cautioned that "the acceptability of the individual elements of the application, including the efficacy and safety evidence, would be determined by the FDA during its substantive review of the complete NDA." The 8-K was signed by Bryan Giraudo, Chief Financial Officer and Chief Operating Officer, and contains forward-looking statements that the company cautions are subject to risks and uncertainties, including the possibility that the FDA may not accept or approve the filing.

What Was Disclosed

Gossamer Bio reported submitting its first NDA to the FDA for seralutinib to treat PAH, supported by Phase 3 PROSERA and Phase 2 TORREY study data, following a Pre-NDA Type B meeting with the FDA in June 2026. FDA acceptance for filing is anticipated later this year.