Gossamer Bio plans a September 2026 FDA NDA submission for seralutinib in pulmonary arterial hypertension after favorable pre-NDA meeting feedback and supportive Phase 3 PROSERA data.
Written By: Rishabh Sonawane, BPharm
Reviewed By: Pharmacally Editorial Team
Gossamer Bio has advanced seralutinib toward a planned U.S. regulatory submission after completing a Type B Pre-NDA meeting with the U.S. Food and Drug Administration. Based on the agency’s official meeting minutes, the company intends to submit an NDA for seralutinib in patients with pulmonary arterial hypertension (PAH) in September 2026.
FDA indicated that questions regarding the statistical significance and magnitude of treatment effect observed in the Phase 3 PROSERA study (NCT05934526) represent review issues rather than filing issues. This feedback supports an NDA package built around the Phase 3 trial, complemented by evidence from the Phase 2 TORREY study (NCT04456998) and additional supportive analyses. If accepted for review, the application could receive an FDA decision during the third quarter of 2027.
Seralutinib Targets Key Drivers of Pulmonary Vascular Remodeling
Seralutinib (GB002) is an inhaled small-molecule inhibitor of platelet-derived growth factor receptor (PDGFR), colony stimulating factor 1 receptor (CSF1R), and c-KIT. These signaling pathways contribute to vascular remodeling, inflammation, and smooth muscle proliferation that drive progression of PAH.
Pulmonary arterial hypertension is a progressive, life-threatening disease characterized by elevated pulmonary vascular resistance and right heart failure. Although multiple vasodilator therapies are available, they primarily address symptoms and hemodynamics rather than the underlying vascular remodeling process. Seralutinib is being developed to modify disease biology through targeted inhibition of these pathogenic pathways.
FDA Meeting Supports Planned NDA Filing
The FDA provided recommendations on the planned NDA’s format and content during the pre-NDA meeting held in June 2026. The agency did not identify the observed efficacy questions as barriers to filing, allowing Gossamer to move forward with its planned regulatory submission.
The company emphasized that FDA’s comments reflect the discussion at the meeting, while the agency’s final determination on approval will depend on a complete review of the submitted NDA.
Gossamer Regains Worldwide Rights to Seralutinib
Alongside the regulatory update, Gossamer terminated its collaboration and license agreement with Chiesi, reacquiring worldwide development and commercialization rights for seralutinib.
The agreement returns full control of global development, manufacturing, pricing, commercialization, and lifecycle management to Gossamer. Chiesi will make a one-time $5 million payment to Gossamer following execution of the agreement, covering all outstanding obligations under the previous collaboration. Gossamer will not make an upfront payment to recover the rights.
Under the revised arrangement, Chiesi remains eligible for capped royalties on worldwide net sales and specified regulatory and commercial milestone payments. Once the royalty cap is reached, no further royalty payments will be owed.
Leadership Highlights Regulatory and Commercial Readiness
Chairman, Co-Founder, and Chief Executive Officer Faheem Hasnain said the FDA meeting and subsequent meeting minutes provide greater clarity on the regulatory pathway for seralutinib. He also highlighted the strategic importance of regaining worldwide rights, noting that the move gives Gossamer greater operational flexibility while preserving most of the program’s long-term commercial value.
Regulatory Path Forward
Gossamer expects to submit the seralutinib NDA in September 2026 using the Phase 3 PROSERA trial as the primary evidence of efficacy, supported by Phase 2 TORREY data and additional analyses. The company also plans to implement a reverse stock split during or shortly after the third quarter of 2026, subject to final board approval, to maintain Nasdaq listing compliance and support its anticipated transition toward potential commercialization.
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About the Writer
Rishabha Sonawane, B.Pharm (LinkedIn) is healthcare writer with a strong interest in medical writing, regulatory affairs, clinical research, and AI-driven drug discovery. He has completed specialized training from the NIH and ICMR in clinical pharmacology, clinical research, and scientific writing. Passionate about evidence-based healthcare communication, he focuses on translating complex scientific research into clear, accurate, and engaging medical content.