WESTLAKE VILLAGE, Calif. — May 6, 2026 — Leads & Copy — MannKind Corporation (Nasdaq: MNKD) is developing a dry powder inhalation (DPI) formulation of ralinepag, known as ralinepag DPI (MNKD-1501), for United Therapeutics Corporation (Nasdaq: UTHR) under an expanded license and collaboration agreement announced in August 2025.
United Therapeutics made an additional $5 million payment to MannKind in April 2026 to support the advancement of ralinepag DPI. MannKind is eligible to receive up to $35 million in development milestone payments and 10% royalties on net sales of any resulting commercial product.
Ralinepag is an investigational prostacyclin receptor agonist that exhibits a long half-life and high potency in the pulmonary vasculature. United Therapeutics reported in March 2026 that its long-term pivotal phase 3 ADVANCE OUTCOMES study of ralinepag extended-release tablets in pulmonary arterial hypertension (PAH) met its primary endpoint with high statistical significance.
According to Martine Rothblatt, Ph.D., Chairperson and Chief Executive Officer of United Therapeutics, the company believes ralinepag has the potential to redefine the PAH treatment landscape and views ralinepag DPI as an important component of long-term success to help broaden real-world use and support patients over time.
United Therapeutics believes the half-life of ralinepag may support once-daily dosing of ralinepag DPI. The companies are currently formulating ralinepag DPI for United Therapeutics’ planned non-clinical studies and a subsequent phase 1 study in healthy volunteers to assess dosing and pharmacokinetic comparability with oral ralinepag tablets. This will inform a pivotal study in PAH patients to further assess safety and PK comparability. United Therapeutics initially intends to seek approval of ralinepag DPI for PAH and also plans to develop the product for pulmonary hypertension associated with interstitial lung disease (PH-ILD), idiopathic pulmonary fibrosis (IPF), and progressive pulmonary fibrosis (PPF), which will require additional clinical studies assessing safety and efficacy in patients with these conditions. Ralinepag is currently not approved in any jurisdiction to treat any of these conditions, in any formulation.
Michael Castagna, PharmD, Chief Executive Officer of MannKind Corporation, stated that they have been working on the ralinepag DPI formulation for the past six months. He added that the company is pleased to apply its dry powder development expertise to advance ralinepag DPI and that this program further validates MannKind’s role as a partner of choice for inhaled delivery of complex and high-value therapeutics.
Ralinepag DPI (MNKD-1501) is being advanced under the companies’ existing worldwide collaboration agreement, pursuant to which United Therapeutics leads global development, regulatory, and commercialization activities and MannKind supports formulation and supply activities.
The original 2018 agreement with United Therapeutics led to the successful development and FDA approval of Tyvaso DPI® in May 2022. In 2025, United Therapeutics reported that Tyvaso DPI generated revenue of $1.3B.
MannKind Corporation (Nasdaq: MNKD) is a biopharmaceutical company dedicated to transforming chronic disease care through innovative, patient-centric solutions. Focused on cardiometabolic and orphan lung diseases, the company develops and commercializes treatments that address serious unmet medical needs, including diabetes, pulmonary hypertension, and fluid overload in heart failure and chronic kidney disease. With deep expertise in drug-device combinations, MannKind aims to deliver therapies designed to fit seamlessly into daily life.
TYVASO DPI is a registered trademark of United Therapeutics Corporation. MANNKIND is a registered trademark of MannKind Corporation.
Source: MannKind Corporation
