Phase 2 Study to Assess Safety, Tolerability and Efficacy of Once Weekly SC Pemziviptadil (PB1046) in Subjects With Symptomatic PAH

Inclusion Criteria: * Male and female subjects with PAH, ≥18 and ≤ 79 years of age, who are symptomatic and have reduced exercise capacity due primarily to their PAH diagnosis and have been assessed by a qualified individual (i.e. physician, physician assistant, nurse practitioner) to be in NYHA/WHO functional class II or III; * Willing and able to sign a written informed consent prior to all study-related procedures; * Subjects with PAH belonging to one of the following subgroups of the Nice Clinical Classification of Pulmonary Hypertension Group 1: a. Idiopathic, b. Heritable, c. Drug or toxin-induced, d. Associated with connective tissue disease, HIV infection, portal hypertension, congenital heart disease (pulmonary-to-systemic shunt; * Two 6MWD test results \> 50 m and \< 550 m prior to randomization with results +/- 10% of each other. Note: Up to four tests may be conducted between Screening and Randomization for eligibility purposes; * Hemodynamic assessment of PAH demonstrating elevated mPAP and PVR as indicated below during the Screening Period: a. mean pulmonary artery pressure (mPAP) of ≥ 25 mmHg; and, b. pulmonary vascular resistance (PVR) ≥ 400 dyne•sec/cm5; and, c. pulmonary capillary wedge pressure (PCWP) or left ventricular end diastolic pressure (LVEDP) of ≤ 12 mmHg if PVR ≥ 400 and \< 500 dynes•sec/cm5; or PCWP/LVEDP ≤ 15 mmHg if PVR ≥ 500 dynes•sec/cm5; * Body mass index ≥ 18 kg/m2 and ≤ 40 kg/m2 at screening; * Meet the following criteria determined by pu…