Japan's Ministry of Health, Labour and Welfare (MHLW) has approved Brinsupri (brensocatib) for non-cystic fibrosis bronchiectasis (NCFB) in adults and pediatric patients aged 12 years and older, making it the first approved treatment for the condition in Japan. Bridgewater, New Jersey-based Insmed Incorporated (Nasdaq: INSM) now holds approvals in the US, EU, and Japan for the oral, once-daily dipeptidyl peptidase 1 (DPP1) inhibitor, which received US FDA approval in August 2025 as the first therapy specifically indicated for NCFB.
The Japan approval covers brensocatib 25 mg tablets taken once daily, with no additional biomarker or exacerbation-history qualifier — a broader label than the EU and UK, where approval requires at least two exacerbations in the prior 12 months. Brensocatib acts by reversibly inhibiting DPP1, a lysosomal cysteine protease that activates neutrophil serine proteases during neutrophil maturation in the bone marrow; blocking this upstream step reduces chronic neutrophilic airway inflammation without directly depleting circulating neutrophils.
The MHLW decision is based on the Phase III ASPEN study, in which brensocatib 25 mg significantly reduced pulmonary exacerbation rates versus placebo over 52 weeks, prolonged time to first exacerbation, and increased the proportion of patients remaining exacerbation-free. Patients on the 25 mg dose also showed significantly lower lung function decline at week 52, measured by post-bronchodilator forced expiratory volume in one second (FEV1). The most common treatment-emergent adverse events occurring in at least 5% of patients were COVID-19, nasopharyngitis, cough, and headache.