The Phase IIb CEDAR trial evaluated Brinsupri at 10mg and 40mg doses in HS patients, measuring reductions in total abscess and inflammatory nodules from baseline. Both doses achieved 45.5% and 40.3% reductions versus a 57.1% placebo decline, missing the study’s primary efficacy endpoint.

Brinsupri also failed all secondary endpoints, including clinical response rates, number of flares, symptomatic severity and quality-of-life scores. Safety data showed one severe treatment-emergent adverse event (1.4%) and three serious events (4.1%) in the 10mg cohort, with overall tolerability consistent across groups.

This halt follows Brinsupri’s December 2025 Phase II miss in chronic rhinosinusitis without nasal polyps, marking a second unsuccessful label-expansion effort. Market sentiment had already tempered expectations due to limited preclinical support for DPP1 inhibition in HS.

Insmed’s focus now shifts to Brinsupri’s approved non-cystic fibrosis bronchiectasis indication, secured in August 2025. Sales forecasts anticipate blockbuster status by 2027 and $5.5 billion revenues by 2031, and analysts expect this HS setback to have minimal impact on investor sentiment.