Clinical Trials

Inclusion Criteria:

• Diagnosis of idiopathic pulmonary arterial hypertension (IPAH), heritable pulmonary arterial hypertension (HPAH), drug- and toxin-induced PAH, or PAH associated with connective tissue disease, HIV infection, or congenital heart defects (repaired greater than 1 year prior to Screening)

• Meet all of the following hemodynamic criteria by means of a screening right heart catheterization (RHC) completed prior to randomization:

  • Mean pulmonary artery pressure (mPAP) of ≥ 25 mm Hg
  • Pulmonary vascular resistance (PVR) ≥ 400 dyne•sec/cm^5
  • Pulmonary capillary wedge pressure (PCWP) or left ventricular end diastolic pressure (LVEDP) of ≤ 12 mm Hg if PVR ≥ 400 and < 500 dynes•sec/cm^5, or PCWP/LVEDP ≤ 15 mm Hg if PVR ≥ 500 dynes•sec/cm^5
• Be able to walk a distance of at least 100 m
• Have World Health Organization (WHO) Functional Class II or III symptoms

• Meet the following criteria determined by pulmonary function tests completed no more than 24 weeks prior to screening, performed with or without bronchodilation:

  • Forced expiratory volume in one second (FEV1) ≥ 55% of predicted normal
  • FEV1:forced vital capacity (FVC) ratio ≥ 0.60
• Receiving treatment with one or more drugs approved for PAH for ≥ 12 consecutive weeks and at stable dose for ≥ 8 consecutive weeks

Exclusion Criteria:

• Diagnosis of PAH associated with significant venous or capillary involvement (PCWP > 15 mm Hg), pulmonary capillary hemangiomatosis, portal hypertension, or unrepaired congenital heart defects
• Pulmonary hypertension (PH) belonging to groups 2 to 5 of the 2013 NICE classification
• Left ventricular ejection fraction (LVEF) ≤ 40% or clinically significant ischemic, valvular or constrictive heart disease
• Uncontrolled hypertension (≥ 180/110 mm Hg) at Screening
• End stage renal disease (receiving peritoneal dialysis, hemodialysis, or status after renal transplantation)
• Severe liver disease (Child-Pugh Class C, with or without cirrhosis)

Individuals may be rescreened one additional time with prior notification to and approval by the sponsor.