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Dec 18, 2025 12:40 PM

Why Is Insmed Stock Falling Thursday?

Insmed Incorporated (NASDAQ:INSM) stock plunged on Thursday.

• Insmed stock is showing notable weakness. What’s behind INSM decline?

The company released data from the Phase 2b BiRCh study of brensocatib in patients with chronic rhinosinusitis without nasal polyps (CRSsNP).

The trial 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.

Also Read: Lung Disease-Focused Insmed ‘Must-Own’ Name For Investors

“Given that there are no animal models in this disease, the purpose of this proof-of-concept study was to determine if brensocatib could provide ...