Insmed Halts Brensocatib CRSsNP Program After Phase 2b Misses Both Primary And Secondary Endpoints; Acquires Phase 2 Ready Monoclonal Antibody For Potential Respiratory And Immunological & Inflammatory Indications

—Phase 2b BiRCh Study of Brensocatib in CRSsNP Did Not Meet Primary or Secondary Efficacy Endpoints; Safety Consistent with Previous Studies; Insmed Discontinues CRSsNP Program—

—Company Acquires Phase 2 Ready Monoclonal Antibody for Potential Respiratory and Immunological & Inflammatory Indications—

BRIDGEWATER, N.J., Dec. 17, 2025 /PRNewswire/ -- Insmed Incorporated (NASDAQ:INSM), a people-first global biopharmaceutical company striving to deliver first- and best-in-class therapies to transform the lives of patients facing serious diseases, announced today that the Phase 2b BiRCh study of brensocatib in patients with chronic rhinosinusitis without nasal polyps (CRSsNP) did not meet its primary or secondary efficacy endpoints in either the 10 mg or 40 mg treatment arms. Brensocatib was well tolerated, with no new safety signals identified, including in the 40 mg arm, which is the highest dose Insmed has studied to date. Insmed has discontinued its development program of brensocatib in CRSsNP effective immediately and intends to present these data at a future congress.