United Therapeutics is a specialty pharmaceutical company focused on treating rare cardiopulmonary diseases, primarily pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD). The company's core product portfolio centers on treprostinil, a prostacyclin analogue that relaxes pulmonary blood vessels, marketed in multiple delivery forms to serve patients across different stages of disease severity. Tyvaso DPI (inhaled dry powder) and Nebulized Tyvaso together drive the majority of revenue, with Remodulin (continuous injection for severe PAH patients) and Orenitram (oral tablets) rounding out the prostacyclin franchise. United Therapeutics also sells Unituxin, a biologic for pediatric neuroblastoma. In the U.S., United Therapeutics sells exclusively through two specialty distributors, Accredo and CVS Specialty. The business model benefits from chronic, progressive diseases that keep patients on therapy indefinitely, often at escalating doses and across multiple formulations, creating a natural treatment continuum within the portfolio. United Therapeutics typically raises prices annually and operates with notable efficiency — roughly 1,400 employees and a self-imposed cap of 50% of prior-year revenue on cash operating expenses. Key near-term growth catalysts include a potential Tyvaso approval in idiopathic pulmonary fibrosis, where a Phase 3 trial met its primary endpoint in 2025, and ralinepag, a once-daily oral prostacyclin receptor agonist in Phase 3. Longer term, United Therapeutics is investing heavily in xenotransplantation, developing gene-edited pig organs as alternatives to human donor transplants.