United Therapeutics’ drug slows progression of rare lung condition in late-stage study

By Padmanabhan Ananthan

March 2 (Reuters) – United Therapeutics said on Monday its experimental drug to treat a rare lung condition cut the risk of the disease worsening by 55% in a late-stage study.

The once-daily pill, ralinepag, was tested in patients with pulmonary arterial hypertension (PAH), a condition where small arteries in the lungs constrict causing high blood pressure in the organ and strain on the right side of the heart.

The Silver Spring, Maryland-based company said the experimental drug was generally well tolerated and it plans to file for an approval from the U.S. Food and Drug Administration in the second half of 2026. Its shares were up 1.4% in afternoon trading.

United Therapeutics already markets other FDA-approved PAH treatments, including thrice-daily oral drug Orenitram, continuous infusion therapy, Remodulin and inhaler-based Tyvaso and Tyvaso DPI.

“Anytime you can reduce the pill burden for the patient population, I think you have a great opportunity,” said Derek Solum, senior director of product development at United Therapeutics.

The company said ralinepag showed other benefits such as improvements in the distance patients could walk in a set period and a reduction in a blood marker used to track stress on the heart by week 28.

“The results look strong,” H.C. Wainwright analyst Andrew Fein told Reuters. He expects ralinepag to win the FDA approval and sees strong uptake among frontline PAH patients.

If approved, ralinepag would compete with Merck’s injectable Winrevair and orals such as Johnson & Johnson’s Opsynvi and Gilead Sciences’ Letairis in a crowded market for PAH drugs.

Alongside United Therapeutics, Johnson & Johnson is among the largest sellers of PAH drugs, with its Opsynvi and Uptravi franchise generating sales worth more than $4 billion in 2025.

(Reporting by Padmanabhan Ananthan in Bengaluru; Editing by Vijay Kishore and Diti Pujara)