Insmed reports 12-month OLE data for TPIP in pulmonary arterial hypertension

Insmed Incorporated announced on July 16, 2026 positive 12-month data from its ongoing open-label extension (OLE) study of treprostinil palmitil inhalation powder (TPIP) in patients with pulmonary arterial hypertension (PAH, WHO Group 1). The OLE study is a non-placebo-controlled trial designed to evaluate the long-term safety, tolerability, and effectiveness of TPIP over 24 months in patients who completed the lead-in TPIP PAH studies.¹

Patients in the Placebo Crossed group (N=31) showed outcomes similar to patients in the TPIP Continued group (N=60) across all efficacy measures at Month 12, with mean 6MWD improvement of +55.7 meters in the TPIP Continued group versus +54.1 meters in the Placebo Crossed group.¹ NT-proBNP concentration fell by roughly 60% in both groups, with geometric mean ratios to baseline of 0.40 and 0.41 in the TPIP Continued and Placebo Crossed groups, respectively.¹ WHO Functional Class I or II was reached by 78.3% of the TPIP Continued group and 80.6% of the Placebo Crossed group.¹ Mean REVEAL Lite 2.0 score improved 2.0 points in the TPIP Continued group and 1.4 points in the Placebo Crossed group, and about 65% of all patients reached Refined Low Risk status.¹

On safety, once-daily TPIP was generally well tolerated with no newly identified safety signals at doses up to 1,280 µg through month 12; treatment-emergent adverse events occurred in 89.0% of the 91 patients, serious TEAEs in 18.7%, severe TEAEs in 16.5%, discontinuations due to TEAEs in 7.7%, and there were four deaths, none considered related to TPIP.¹

The findings support continued development of TPIP, including the recently initiated Phase 3 PALM-PAH trial, a randomized, double-blind, placebo-controlled study evaluating once-daily TPIP over 24 weeks with change in 6MWD as the primary endpoint.¹ Insmed said it plans to publish the full 12-month OLE results in the future.¹