Insmed’s ‘Unprecedented’ Phase 2 PAH Results Propel Stock and Next-Phase Plans

Insmed announced positive topline results from its Phase 2b study of treprostinil palmitil inhalation powder (TPIP) as a once-daily therapy for pulmonary arterial hypertension (PAH)15.

The trial met its primary endpoint, showing a 35% placebo-adjusted reduction in pulmonary vascular resistance (PVR) at week 16 (p<0.001)35.

Secondary endpoints were also achieved, including a 35.5-meter placebo-adjusted improvement in six-minute walk distance and a 60% reduction in NT-proBNP, a cardiac stress biomarker35.

75% of patients reached the maximum tolerated dose, and the safety profile was favorable with no deaths or significant red flags, though some mild adverse events (e.g., cough, headache) were more common in the TPIP group3.

The results were described as "statistically significant and clinically meaningful," prompting a surge of more than 27% in Insmed's stock price5.

Insmed immediately began engagement with the US FDA to discuss Phase 3 trial design and plans to launch two large Phase 3 studies—one in PAH next year, and one in pulmonary hypertension associated with interstitial lung disease before year-end52.

TPIP offers once-daily inhaled dosing, a significant improvement over existing prostanoids that require more frequent administration, potentially boosting patient adherence and outcomes3.

Sources:

1. https://investor.insmed.com/2025-06-10-Insmed-Announces-Positive-Topline-Results-from-Phase-2b-Study-of-Treprostinil-Palmitil-Inhalation-Powder-TPIP-as-Once-Daily-Therapy-in-Patients-with-Pulmonary-Arterial-Hypertension

2. https://investor.insmed.com/image/Insmed+TPIP+Phase+2b+in+PAH+Topline+Results+Presentation+(PDF).pdf

3. https://www.ainvest.com/news/insmed-phase-2b-breakthrough-era-pah-treatment-investor-opportunities-2506/

5. https://www.proactiveinvestors.com/companies/news/1072717/insmed-shares-surge-on-positive-trial-results-for-pulmonary-arterial-hypertension-therapy-1072717.html