Insmed Eyes Label Expansion After 82.4% Culture Conversion in ENCORE Trial
Insmed’s ENCORE Phase IIIb trial of inhaled Arikayce plus azithromycin and ethambutol hit its primary respiratory symptom endpoint and delivered 82.4% culture conversion versus 55.6% placebo at month 13. The company will submit supplemental NDAs in the US and Japan in H2 2026 seeking earlier label expansion.
1. ENCORE Phase IIIb Trial Outcomes
Insmed enrolled 425 treatment-naïve patients across 258 sites in its ENCORE Phase IIIb study, evaluating inhaled Arikayce combined with azithromycin and ethambutol. The trial met its primary endpoint by significantly improving respiratory symptom scores at month 13 versus placebo.
2. Culture Conversion and Safety
Arikayce achieved an 82.4% culture conversion rate at 13 months compared to 55.6% with placebo; severe treatment-emergent adverse events occurred in 32% of patients on Arikayce, leading to a 31% discontinuation rate versus 18% for placebo.
3. Planned Label Expansion
Insmed plans to submit supplemental NDAs in the US and Japan in H2 2026 to expand Arikayce’s label into earlier treatment lines, targeting a potential launch in the expanded population by 2027.