Gossamer Bio's Seralutinib Misses Primary Endpoint but Shows Promise in High-Risk PAH Patients
Event summary
- Gossamer Bio's Phase 3 PROSERA study of seralutinib in PAH patients missed the primary endpoint (p=0.0320 vs. prespecified α=0.025) but showed a statistically significant improvement in 6MWD (+13.3m, p=0.0320).
- In high-risk patients (REVEAL Lite 2 score ≥6), seralutinib demonstrated a +20.0m placebo-adjusted improvement in 6MWD (p=0.0207) and strong results across key secondary endpoints.
- The study enrolled 390 patients, with 55% on triple/quadruple background PAH therapy and 61% on prostacyclin therapy.
- Gossamer Bio plans to discuss the path forward for seralutinib with the FDA and is pausing enrollment in the SERANATA study.
The big picture
Gossamer Bio's seralutinib represents a novel approach to PAH treatment, targeting key growth factor receptors implicated in the disease. While the Phase 3 PROSERA study missed its primary endpoint, the robust results in high-risk patients highlight the drug's potential in a population with significant unmet need. The company's collaboration with Chiesi Group underscores the strategic importance of seralutinib in addressing this rare and progressive condition.
What we're watching
- Regulatory Strategy
- Whether the FDA will accept the compelling data in high-risk patients as sufficient for approval, given the narrow miss on the primary endpoint.
- Clinical Development
- The pace at which Gossamer Bio can design and execute a new clinical strategy that leverages the strong signals in high-risk PAH patients.
- Competitive Positioning
- How seralutinib's differentiated, nonvasodilatory mechanism will position it against existing and emerging PAH therapies if approved.