Insmed Incorporated (NASDAQ:INSM) on Thursday reported 12-month results from the ongoing open-label extension (OLE) study of its once-daily treprostinil palmitil inhalation powder (TPIP) in pulmonary arterial hypertension (PAH) patients.
PAH is a rare, progressive disease where the tiny arteries in the lungs narrow, increasing blood pressure and forcing the heart to work harder.
Sustained Efficacy Seen Across Key Clinical Measures
The company said the data showed sustained improvements across multiple efficacy measures and similar benefits among patients who switched from placebo to TPIP, reinforcing its confidence as the Phase 3 PALM-PAH trial moves forward.
The OLE study was designed to assess the long-term safety, tolerability, and effectiveness of TPIP over 24 months in patients who completed earlier TPIP PAH studies.
The non-placebo-controlled trial enrolled patients who either continued TPIP treatment or crossed over from placebo.
Patients Continuing And Switching To TPIP Posted Similar Results
At the 12-month mark, patients who remained on TPIP (n=60) and those who switched from placebo (n=31) produced comparable outcomes across all major efficacy endpoints.
Patients continuing TPIP improved their six-minute walk distance by an average of 55.7 meters from baseline, while those crossing over from placebo improved by 54.1 meters.
Both groups also recorded roughly a 60% reduction in N-terminal fragment pro-B-type natriuretic peptide (NT-proBNP, a biomarker for heart failure) concentrations.
In addition, 78.3% of patients in the TPIP continued group and 80.6% in the placebo crossover group achieved World Health Organization Functional Class I or II by Month 12.
More than one-quarter of patients across both groups reached Functional Class I.
The mean REVEAL Lite 2.0 score improved by 2.0 points in the TPIP continued group and 1.4 points among patients who switched from placebo.
Approximately 65% of patients achieved Refined Low Risk status, which is associated with an estimated mortality risk of less than 5% over three years and about a 7% risk of clinical worsening within one year.
Safety Profile Supports Ongoing Phase 3 Development
Insmed said once-daily TPIP remained generally well tolerated at doses up to 1,280 micrograms through Month 12, with no newly identified safety signals.
The company said the findings support continued development of TPIP and the recently initiated Phase 3 PALM-PAH trial.
INSM Stock Price Activity: Insmed shares were down 3.67% at $105.77 at the time of publication on Thursday, according to Benzinga Pro data.
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