Insmed shares surge on Phase III brensocatib results in bronchiectasis

Insmed's shares soared by up to 140% on Tuesday following the announcement that its drug brensocatib achieved positive results in a Phase III clinical trial for patients with non-cystic fibrosis bronchiectasis. The trial revealed that brensocatib significantly reduced pulmonary exacerbations compared to a placebo. The company is preparing to submit a new drug application to the FDA in the fourth quarter, with a projected U.S. launch in mid-2025. If approved, brensocatib would become the first authorized treatment for bronchiectasis and the first DPP1 inhibitor on the market.

Martina Flammer, Insmed's chief medical officer, stated, "We now look forward to further analysing the data while rapidly advancing toward regulatory filings in our key regions, where we believe approximately 1 million bronchiectasis patients may benefit from an approved treatment."

The ASPEN study, which underpinned these findings, involved 1680 adults who were randomly assigned to receive either a 10 mg dose, a 25 mg dose of brensocatib, or a placebo daily for 52 weeks, followed by a four-week off-treatment period. Additionally, 41 adolescents participated, randomized in a 2:2:1 ratio. The primary endpoint was met with significant reductions in the annual rate of pulmonary exacerbations, showing a decrease of 21.1% with the 10 mg dose and 19.4% with the 25 mg dose compared to the placebo. Both dosages also successfully achieved several secondary endpoints, such as prolonging the time to the first pulmonary exacerbation and increasing the likelihood of remaining exacerbation-free over the 52-week period. Importantly, the higher dose resulted in a significant 38 mL improvement from baseline in post-bronchodilator forced expiratory volume in one second (FEV1) at week 52.

Brensocatib was generally well-tolerated among participants. The most common treatment-emergent adverse events, occurring in at least 5% of patients on either dose and more frequently than in the placebo group, included COVID-19, nasopharyngitis, cough, and headache.

Insmed plans to launch brensocatib as a bronchiectasis treatment in Europe and Japan in the first half of 2026. Beyond bronchiectasis, the company is also exploring the potential of brensocatib in treating other neutrophil-driven inflammatory diseases, such as chronic rhinosinusitis without nasal polyps and hidradenitis suppurativa.

JPMorgan analyst Jessica Fye described the study's results as a "home run scenario," suggesting that these findings could significantly enhance Insmed's value and transform the company. Similarly, TD Cowen analyst Ritu Baral emphasized the substantial unmet need for bronchiectasis treatments and noted that the data supports brensocatib's approval, potentially creating a significant blockbuster market opportunity.

In summary, Insmed's brensocatib has shown promising results in reducing pulmonary exacerbations in non-cystic fibrosis bronchiectasis patients during a Phase III study. The drug is on track for an FDA submission and potential U.S. launch by mid-2025, with subsequent launches in Europe and Japan anticipated for 2026. If approved, brensocatib could become a pioneering treatment for bronchiectasis and open new avenues for treating other inflammatory conditions.