A Study of a Mean Pulmonary Artery Pressure-Targeted Approach With Early and Rapid Treprostinil Therapy to Reverse Right Ventricular Remodeling in Participants With Pulmonary Arterial Hypertension

Inclusion Criteria: * Confirmed PAH (WHO Group 1) classified by one of the following subgroups: * Idiopathic, heritable or drug/toxin induced (with the exception of amphetamine-induced PAH) * Associated with repaired congenital systemic-to-pulmonary shunts (repaired ≥1 year) * Associated with connective tissue disease * Associated with human immunodeficiency virus infection * Baseline visit right heart catheterization (RHC) must also meet the following criteria: * mPAP \>35 mmHg * Pulmonary vascular resistance (PVR) \>2 Wood units * Pulmonary artery wedge pressure (PAWP) ≤15 mmHg * On a stable dose of an endothelin receptor antagonist (ERA) and/or phosphodiesterase type 5 inhibitor (PDE-5i) or soluble guanylate cyclase stimulator (sGC) therapy or if treatment naïve, willing to take one of these medications in addition to study drug * REVEAL Lite 2 risk score ≤9 * WHO FC II or III * 6MWD \>165 meters Exclusion Criteria: PAH-related Exclusion Criteria: * Prior or current use of epoprostenol, treprostinil, iloprost, beraprost, or selexipag * Positive vasoreactivity test in idiopathic, heritable, or drug/toxin induced PAH * Amphetamine use within the past 12 months * WHO Groups 2, 3, 4, and 5 * Use of any other investigational drug, device, or therapy within 30 days of the Baseline visit * Moderate or severe hepatic impairment (Child-Pugh Class B and C) * Any other clinically significant illness or abnormal laboratory value(s) measured during screening that, i…