Insmed’s Inhalation Powder meets endpoints in Phase 2b PAH trial

Insmed (INSM) announced positive topline results from its randomized, double-blind, placebo-controlled Phase 2b study evaluating the efficacy and safety of treprostinil palmitil inhalation powder, or TPIP, administered once daily in patients with pulmonary arterial hypertension – PAH -. The study met its primary endpoint and all secondary efficacy endpoints. For the primary endpoint, the placebo-adjusted reduction from baseline in pulmonary vascular resistance, or PVR, was 35%. For the secondary efficacy endpoints, the placebo-adjusted improvement in six-minute walk distance was 35.5 meters and the placebo-adjusted reduction from baseline in N-terminal pro b-type natriuretic peptide concentrations, a biomarker for cardiac stress, was 60% with LS mean ratio of 0.40. These results demonstrate the durability of TPIP’s therapeutic effect as a once-daily therapy based on efficacy being evaluated approximately 24 hours after therapy was administered. Based on these results, Insmed will immediately engage with the FDA regarding the Phase 3 trial design for PAH. Insmed plans to initiate a Phase 3 trial in patients with pulmonary hypertension associated with interstitial lung disease before the end of 2025 and a Phase 3 trial in patients with PAH in early 2026. Once-daily TPIP therapy was well tolerated in the study. Treatment-emergent adverse events occurred in 88.4% of patients who received TPIP versus 75.8% of patients who received placebo; serious TEAEs were observed in 7.2% of patients who received TPIP versus 3.0% of patients who received placebo; and severe TEAEs were observed in 5.8% of patients who received TPIP versus 3.0% of patients who received placebo. TEAEs leading to treatment discontinuation were experienced by 5.8% of patients taking TPIP; there were none in the placebo arm.