Insmed Stock Jumps 29% on Encouraging PAH Study Results

Shares of Insmed INSM soared nearly 29% yesterday after the company reported positive top-line data from a phase IIb study evaluating its investigational treprostinil palmitil inhalation powder (TPIP) in patients with pulmonary arterial hypertension (PAH).

The study achieved its primary endpoint – TPIP-treated participants achieved a statistically significant reduction in pulmonary vascular resistance (PVR) levels. Specifically, treatment with the drug led to placebo-adjusted reductions of 35%. PVR measures pressure in the lung blood vessels.

The study also met all secondary efficacy endpoints. Treatment with the drug showed a placebo-adjusted improvement in a six-minute walk distance (6MWD) of 35.5 meters and a placebo-adjusted reduction of 60% in N-terminal pro b-type natriuretic peptide (NT-proBNP) concentrations. The 6MWD measures a patient’s exercise capacity, while NT-proBNP is a biomarker of heart strain.

Based on the above results, Insmed plans to “immediately engage” with the FDA on the design for a late-stage study on the drug in the PAH indication. It aims to start this study in early 2026. The company also plans to present detailed results from the study at a future medical meeting.

PAH is a rare, progressive disease in which the blood vessels in the lungs narrow or become obstructed, leading to high blood pressure in the pulmonary arteries and forcing the heart to work harder. Common symptoms include shortness of breath, chest pain, dizziness or fainting, fatigue and weakness. Insmed estimates that nearly 90,000 patients living across the United States, Europe and Japan are diagnosed with PAH.

INSM Stock Performance

Year to date, shares of Insmed have surged 32% against the industry’s 1% decline.

More on INSM’s TPIP

Apart from PAH, Insmed is also developing TPIP for patients with pulmonary hypertension associated with interstitial lung disease (PH-ILD). Last year, the company reported results from a mid-stage study on the drug in PH-ILD patients. The data showed that treatment with TPIP has the potential to prolong the duration of the effect and reduce dose frequency compared with existing inhaled prostanoid therapies.

Based on these findings, Insmed intends to initiate a late-stage PH-ILD study in the second half of 2025, which may further expand TPIP’s competitive reach if successful.

Why Did UTHR Stock Decline on INSM’s News?

Insmed’s TPIP is a prodrug of United Therapeutics' UTHR treprostinil, the active ingredient in its blockbuster Tyvaso products. A prodrug is an inactive compound that becomes active once inside the body, allowing TPIP to release treprostinil more gradually. This extended-release design enables once-daily dosing, compared to United Therapeutics’ Tyvaso, which requires multiple daily doses using either a nebulizer or a dry powder inhaler. Tyvaso products are approved for PAH and PH-ILD indications.

Across both the PAH & PH-ILD studies, Insmed claimed that a majority of patients who received TPIP reached the maximum dose of 640 micrograms (µg) following five weeks of treatment. This once-daily 640 µg dose of TPIP contains approximately 60% more treprostinil than current market products, which are dosed four times daily. If approved, TPIP’s simplified, once-daily, capsule-based inhalation could offer a meaningful advantage in convenience and adherence over Tyvaso’s more frequent dosing.

This potential threat to Tyvaso’s franchise likely contributed to the 14% decline in UTHR’s stock price yesterday. Shares of Liquidia Corporation LQDA also declined 17% on the news, as Insmed’s promising data may create long-term headwinds for its newly approved Yutrepia, another inhaled treprostinil product that requires multiple daily doses.

Liquidia’s Yutrepia only recently entered the market after years of legal battles with United Therapeutics, which had sought to block its approval. UTHR sued both Liquidia and the FDA, but its broad exclusivity on dry-powder treprostinil expired last month, clearing the way for Yutrepia’s long-awaited FDA approval. While Tyvaso has been on the market since 2009 for PAH and was approved for PH-ILD in 2021, Yutrepia marked the first inhaled competitor for both indications.

Insmed, Inc. Price

 

Insmed, Inc. price | Insmed, Inc. Quote

INSM’s Zacks Rank

Insmed currently carries a Zacks Rank #4 (Sell).

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This article originally published on Zacks Investment Research (zacks.com).

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