Insmed Reports Positive 12-Month TPIP Data, Advances Phase 3 Development in Pulmonary Arterial Hypertension

Insmed Incorporated has announced positive 12-month results from its ongoing open-label extension (OLE) study evaluating treprostinil palmitil inhalation powder (TPIP) in patients with pulmonary arterial hypertension (PAH). The latest findings showed sustained improvements across multiple clinical measures while maintaining a favorable safety profile, further supporting the continued development of the investigational once-daily therapy.

The long-term data also strengthen the company's ongoing Phase 3 PALM-PAH clinical program, which is evaluating TPIP as a potential new treatment option for patients living with PAH.

One-Year Data Show Sustained Clinical Benefits

The OLE study was designed to assess the long-term safety, tolerability, and effectiveness of TPIP in patients who had completed earlier TPIP PAH studies.

According to the company, patients who continued receiving TPIP maintained improvements in several important clinical endpoints over 12 months. Patients who initially received placebo and later switched to TPIP achieved similar outcomes after one year of treatment.

The study demonstrated continued improvements in exercise capacity, heart function biomarkers, disease severity, and overall clinical risk.

Exercise Capacity Continued to Improve

One of the key findings from the study was the sustained improvement in six-minute walk distance (6MWD), an important measure of physical function in pulmonary arterial hypertension.

After 12 months of treatment:

• Patients who remained on TPIP improved their walking distance by an average of 55.7 meters from baseline.
• Patients who crossed over from placebo recorded an average improvement of 54.1 meters.

The results indicate that patients maintained better exercise performance during long-term treatment.

Heart Failure Biomarker Declined Significantly

Researchers also measured N-terminal pro-B-type natriuretic peptide (NT-proBNP), a biomarker commonly used to assess heart stress in patients with pulmonary arterial hypertension.

At Month 12, NT-proBNP levels decreased by approximately 60% in both patient groups, suggesting sustained improvement in cardiovascular status.

Functional Status Improved Across Both Groups

The study also evaluated patients using the World Health Organization (WHO) Functional Class system.

By the end of one year:

• 78.3% of patients who continued TPIP reached WHO Functional Class I or II.
• 80.6% of patients who switched from placebo also achieved WHO Functional Class I or II.

More than one-quarter of patients in both groups reached WHO Functional Class I, indicating minimal disease-related symptoms.

Risk Scores Showed Meaningful Improvement

Patients also demonstrated clinically meaningful improvements in REVEAL Lite 2.0 scores, a widely used tool for estimating disease progression and survival in pulmonary arterial hypertension.

Approximately 65% of all patients achieved Refined Low Risk status after 12 months, a level associated with lower mortality risk and reduced chances of clinical worsening.

Company Highlights Long-Term Potential of TPIP

Gene Sullivan, Chief Product Strategy Officer at Insmed, said the latest results represent another important milestone for the TPIP development program.

He noted that the therapy continued to deliver sustained clinical improvements across multiple efficacy measures while remaining well tolerated over one year of treatment.

According to Sullivan, the new findings, together with previously reported positive Phase 2b results, reinforce TPIP's potential to become a preferred prostanoid therapy for pulmonary arterial hypertension.

Experts See Encouraging Clinical Progress

Dr. Raymond Benza, a member of the Phase 2b Steering Committee and George M. and Linda H. Kaufman Academic Chair of Cardiology at Sentara Health, said the latest data are encouraging for both physicians and patients.

He highlighted the improvements seen in REVEAL Lite 2.0 scores, explaining that previous studies have linked even a one-point improvement with meaningful reductions in mortality risk and disease progression.

According to Dr. Benza, the combination of improved exercise capacity, better functional status, and favorable risk scores provides strong clinical support for advancing TPIP into Phase 3 development.

Safety Profile Remained Consistent

The primary objective of the OLE study was to evaluate long-term safety and tolerability.

Insmed reported that TPIP continued to demonstrate a generally favorable safety profile through 12 months, with no newly identified safety signals.

Among the 91 patients enrolled:

• Treatment-emergent adverse events occurred in 89.0% of patients.
• Serious adverse events occurred in 18.7%.
• Severe adverse events occurred in 16.5%.
• 7.7% of patients discontinued treatment because of adverse events.

Four deaths were reported during the study, although investigators determined that none were related to TPIP treatment.

The most commonly reported adverse events included headache, cough, nasopharyngitis, diarrhea, upper respiratory tract infection, bronchitis, dizziness, epistaxis, nausea, anemia, influenza, and pneumonia.

Phase 3 PALM-PAH Trial Continues

The positive long-term findings support Insmed's ongoing Phase 3 PALM-PAH study.

The randomized, double-blind, placebo-controlled trial is evaluating once-daily TPIP in patients with pulmonary arterial hypertension over a 24-week treatment period.

The primary endpoint is the change in six-minute walk distance, while additional assessments will evaluate safety, tolerability, and overall clinical benefit.

The company also plans to publish the complete 12-month OLE study results in a scientific journal.

About TPIP

Treprostinil palmitil inhalation powder (TPIP) is an investigational once-daily dry powder inhalation therapy developed by Insmed.

The therapy is currently being studied for pulmonary arterial hypertension as well as pulmonary hypertension associated with interstitial lung disease (PH-ILD), progressive pulmonary fibrosis (PPF), and idiopathic pulmonary fibrosis (IPF).

TPIP has not yet received regulatory approval for any indication.

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