INSM · Insmed Incorporated

Summary

Insmed Incorporated announced positive topline results from the Phase 3b ENCORE study evaluating ARIKAYCE plus azithromycin and ethambutol versus placebo plus the same multidrug therapy in 425 patients with newly diagnosed Mycobacterium avium complex lung infection, meeting the primary endpoint of change from baseline in Respiratory Symptom Score at Month 13 (17.77 vs 14.66 points, p=0.0299) and all multiplicity-controlled secondary culture conversion endpoints. The company plans supplemental NDA filing with FDA and data submission to PMDA in second half of 2026 for potential label expansion.

Key takeaways

• ENCORE study met primary endpoint: ARIKAYCE arm 17.77 point improvement vs 14.66 placebo at Month 13, treatment difference 3.11 points, p=0.0299
• Culture conversion by Month 6: 87.8% ARIKAYCE (N=213) vs 57.0% placebo (N=212), p<0.0001
• Durable culture conversion at Month 15: 76.2% vs 47.6%, p<0.0001
• Plans sNDA with FDA in H2 2026 for MAC lung disease label expansion and traditional approval
• Study enrolled 425 patients at 177 global sites; safety profile consistent with known ARIKAYCE profile
• Conference call held March 23, 2026 at 8:00 a.m. ET with webcast on company website