Brensocatib Phase 2b Study in HS Does Not Meet Endpoints, Program Discontinued

Insmed Incorporated has announced its phase 2b CEDAR trial evaluating brensocatib, a dipeptidyl peptidase 1 (DPP1) inhibitor, in adults with moderate to severe hidradenitis suppurativa (HS) failed to achieve both its primary and secondary efficacy endpoints.1

In their April 2026 release, the failure of brensocatib to meet its efficacy endpoints in this new analysis and led the company to discontinue any further development of the therapy for this indication. Despite this, Insmed is slated to present full study results at a future scientific meeting.

"The CEDAR study was designed as a proof-of-concept study to determine whether brensocatib could provide benefit for patients with HS—a disease where the lack of established animal models makes clinical development particularly challenging," Martina Flammer, MD, MBA, Chief Medical Officer of Insmed, said in a statement.1

The CEDAR analysis was designed as a randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of brensocatib across a global cohort of 214 patients, all of whom were enrolled at 72 sites. Those involved were given an assigment, in a 1:1:1 ratio, to once-daily receive brensocatib either at a 10 mg or 40 mg dose or placebo. This treatment schedule took place over an initial 16-week treatment period.

Following this phase of CEDAR, investigators had subjects either continue their assigned brensocatib dose or, if originally assigned to placebo, re-randomized them to be given active treatment. CEDAR’s primary endpoint was the percent change from the point of baseline in participants’ total abscess and inflammatory nodule (AN) count by the 16-week mark. At that time point, reductions in AN count were observed across all groups.

However, the investigative team noted outcomes in the active treatment arms did not surpass those observed among patients treated with placebo. Those on brensocatib 10 mg and 40 mg experienced mean reductions of 45.5% and 40.3%, respectively. This was compared with a 57.1% reduction among those in the placebo arm of the study.

Despite the lack of demonstrated efficacy, the team highlighted brensocatib’s consistent safety profile with prior clinical research. The CEDAR investigators reported a lack of new safety concerns, including in the higher 40 mg dosing arm, which represents the highest dose evaluated by Insmed to date. Rates of treatment-emergent adverse events (TEAEs) were noted as comparable across study cohorts.

During the placebo-controlled period, TEAEs took place among 41 individuals in the 10 mg arm, 30 in the 40 mg arm, and 32 on placebo. Severe adverse events (AEs) were rare, with a single event reported in the 10 mg arm and none in the other arms. Serious AEs were identified by the investigators in 3, 1, and 1 individuals in the 10 mg, 40 mg, and placebo arms, respectively.

Brensocatib previously received approval from the US Food and Drug Administration for the treatment of adult and pediatric patients aged 12 years and older with non-cystic fibrosis bronchiectasis at doses of 10 mg and 25 mg.2 While it discontinued its HS program for this drug, the company’s release highlights the benefits of these findings.

"While we are disappointed in the results, we hope that insights gained from this study will contribute to the broader scientific understanding of HS,” Flammer said in a statement.1 “We are grateful to the patients and investigators who participated in this study."

References

1. Insmed Provides Clinical Update on Phase 2b CEDAR Study. Insmed. April 7, 2026. Accessed April 14, 2026. https://www.prnewswire.com/news-releases/insmed-provides-clinical-update-on-phase-2b-cedar-study-302736190.html.

2. FDA Approves BRINSUPRI™ (brensocatib) as the First and Only Treatment for Non-Cystic Fibrosis Bronchiectasis, a Serious, Chronic Lung Disease. News release. Insmed. August 12, 2025. Accessed April 14, 2026. https://investor.insmed.com/2025-08-12-FDA-Approves-BRINSUPRI-TM-brensocatib-as-the-First-and-Only-Treatment-for-Non-Cystic-Fibrosis-Bronchiectasis,-a-Serious,-Chronic-Lung-Disease.