Insmed (INSM) said Tuesday that its phase 2b study evaluating treprostinil palmitil inhalation powder in patients with pulmonary arterial hypertension, or PAH, met its primary endpoint and all secondary efficacy endpoints.

The company said it will "immediately" engage with the US Food and Drug Administration for a phase 3 trial design.

According to Insmed, the study met its primary endpoint of 35% placebo-adjusted reduction from baseline in pulmonary vascular resistance. The study also achieved secondary efficacy endpoints of 35.5 meters in six-minute walk distance and 60% reduction from baseline in N-terminal pro b-type natriuretic peptide concentrations, a biomarker for cardiac stress.

The company said it targets to start the phase 3 trial in pulmonary arterial hypertension in early 2026 and a phase 3 trial in patients with pulmonary hypertension associated with interstitial lung disease before the end of 2025.

Insmed also said its treprostinil palmitil inhalation powder was well tolerated in the study.

Shares of Insmed were up more than 20% in recent premarket activity Tuesday.