The FDA decision on United Therapeutics Corp.’s (UTHR) Tyvaso DPI, a novel dry powder inhalation formulation of treprostinil, is expected in October.Tyvaso DPI is proposed for the treatment of pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD).Pulmonary arterial hypertension (PAH) is a rare, progressive disorder characterized by high blood pressure (hypertension) in the arteries of the lungs (pulmonary artery) for no apparent reason. (Source: NORD)Interstitial lung disease (ILD) is a group of lung diseases that are characterized by marked scarring or fibrosis of the bronchioles and alveolar sacs within the lungs. Pulmonary hypertension (PH) frequently complicates the course of patients with interstitial lung disease. Treprostinil in inhaled formulation, developed by United Therapeutics, secured FDA approval in 2009 for the treatment of pulmonary arterial hypertension to improve exercise ability, and in April of this year for the treatment of patients with pulmonary hypertension associated with interstitial lung disease.MannKind and United Therapeutics have a worldwide exclusive licensing and collaboration agreement that was signed in September 2018 for the development and commercialization of Tyvaso DPI.UTHR closed Wednesday’s trading at $185.50, down 1.15%.