FDA Accepts UTHR Once-Daily Oral Ralinepag for PAH

The FDA accepted United Therapeutics’ (Nasdaq: UTHR) new drug application for ralinepag, an oral prostacyclin receptor agonist for pulmonary arterial hypertension (PAH), and set a target decision date of June 24, 2027.

If approved, ralinepag would be the first once-daily oral prostacyclin for PAH. Today’s oral options require more frequent dosing: selexipag (Uptravi) is taken twice daily, and oral treprostinil (Orenitram) multiple times daily. A once-daily pill closes a real convenience gap in a disease where United Therapeutics already leads through its Tyvaso and Orenitram franchises.

The filing rests on ADVANCE OUTCOMES, a global Phase 3 trial of 687 patients randomized 1:1 to ralinepag or placebo on top of standard background therapy, with once-daily dosing titrated to tolerability. It met its primary endpoint with a 55% reduction in the risk of clinical worsening versus placebo. Ralinepag also lowered NT-proBNP, a biomarker tied to heart-failure strain, improved six-minute walk distance, and raised the odds of clinical improvement by 47% (p=0.015). The results were published in The Lancet.

Ralinepag is a highly selective prostacyclin (IP) receptor agonist. United Therapeutics says it binds the IP receptor roughly six-fold more tightly than the active metabolite of selexipag and sustains receptor occupancy closer to parenteral (injected or inhaled) therapy. That is the mechanistic case for durable, disease-mitigating effect rather than temporary symptom relief. PAH is a progressive disease in which rising pressure in the lung’s arteries strains the right side of the heart, advancing toward right heart failure.

United Therapeutics in-licensed ralinepag from Arena Pharmaceuticals in 2018 in a deal carrying $800 million upfront, an outsized bet on a still-unapproved molecule. The company, founded by CEO Martine Rothblatt to treat her daughter’s rare form of the disease, has built its franchise on PAH therapies.

The competitive picture favors United Therapeutics. Gossamer Bio’s seralutinib, another oral PAH candidate, failed its Phase 3 program this summer, leaving the field less crowded. PAH affects roughly 50,000 people in the U.S. and about 500,000 worldwide, and ralinepag extends a franchise United Therapeutics already monetizes at multibillion-dollar scale rather than opening a new market.

United Therapeutics shares closed at $512.88 Monday, little changed on the news.

Source: United Therapeutics ralinepag NDA acceptance press release

What to watch: the June 2027 decision is 10 months out, so the near-term action is limited to any advisory committee the FDA schedules and how a once-daily label, if granted, stacks up against Uptravi. The real question is whether once-daily dosing is enough to dislodge selexipag’s entrenched position in oral PAH.