Gossamer Bio's Seralutinib Misses Primary Endpoint but Shows Promise in Subgroups
Event summary
- Gossamer Bio reported Q4 and full-year 2025 financial results, with cash reserves of $136.9M expected to last into Q1 2027.
- Seralutinib's Phase 3 PROSERA study narrowly missed the primary endpoint but showed significant benefits in high-risk PAH subgroups.
- The company paused enrollment in the SERANATA study for PH-ILD pending further analysis and FDA discussions.
- Gossamer implemented cost-cutting measures, including a reduction in force, to align resources with near-term priorities.
The big picture
Gossamer Bio faces a critical juncture as it navigates the mixed results from its Phase 3 PROSERA study. While the primary endpoint was missed, the promising data in specific patient populations could still position seralutinib as a differentiated therapy if regulatory hurdles are overcome. The company's ability to secure a viable path forward will depend on FDA flexibility and Gossamer's strategic execution amid tightening financial constraints.
What we're watching
- Regulatory Pathway
- Whether the FDA will accept the subgroup data as sufficient for approval during the planned Type C meeting in June 2026.
- Strategic Pivot
- How Gossamer allocates capital and resources following the PROSERA results and workforce reduction.
- Subgroup Validation
- The pace at which additional analyses confirm seralutinib's efficacy in high-risk PAH patients and CTD-PAH subgroups.