Jazz Pharmaceuticals' Zepzelca Misses OS Endpoint with 8.7-Month vs 10.7-Month Control
JAZZ•Jazz Pharmaceuticals' Phase 3 LAGOON trial for Zepzelca in second-line SCLC failed its primary OS endpoint, with median survival of 8.7 months for monotherapy and 10.9 months for the irinotecan combination versus 10.7 months for control. Safety findings were consistent and 2026 guidance is unaffected.
1. LAGOON Trial Overall Survival Results
The randomized Phase 3 LAGOON trial enrolled 724 relapsed SCLC patients and compared Zepzelca monotherapy, Zepzelca plus irinotecan, and investigator’s choice of topotecan or irinotecan. Median overall survival was 8.7 months for monotherapy (HR 1.19 vs control) and 10.9 months for the combination (HR 0.90 vs control) versus 10.7 months for control, missing the primary endpoint.
2. Safety Profile and Adverse Events
No new safety signals emerged. Treatment-related adverse events occurred in 78.5% of patients on Zepzelca monotherapy, 95% on the combination, and 93.8% in the control arm. Grade ≥3 adverse events were reported in 35% of the monotherapy arm, 62.6% of the combination arm, and 64.4% of control.
3. Regulatory Impact and Financial Guidance
Jazz Pharmaceuticals will engage with the FDA on post-marketing requirements for the second-line indication. These LAGOON results do not affect Zepzelca’s first-line maintenance approval or the company’s 2026 financial guidance.
