A Study of Ubenimex in Patients With Pulmonary Arterial Hypertension (WHO Group 1)

Ubenimex is being developed for the treatment of PAH (WHO Group 1) to improve exercise capacity and delay clinical worsening. This proof-of-concept study is designed as a Phase 2, multicenter, randomized, double-blind, placebo controlled study comparing ubenimex with placebo in patients with PAH (WHO Group 1) and have a WHO/NYHA Functional Classification (WHO/NYHA-FC) of II or III. The Primary Objectives for the study are: * To evaluate the efficacy of ubenimex in patients with PAH (WHO Group 1). * To evaluate the safety and tolerability of ubenimex in patients with WHO Group 1 PAH.