- Subjects weighing ≥8 kg.
- Subjects who have symptomatic pulmonary arterial hypertension due to one of the
- Idiopathic pulmonary arterial hypertension; or
- Heritable pulmonary arterial hypertension; or
- Pulmonary arterial hypertension associated with congenital systemic-to-pulmonary
shunts. If the defect(s) is repaired, the subject's condition should be stabilized
- Pulmonary arterial hypertension associated with d-transposition of the great arteries
repaired within the first 30 days of life; or
- Pulmonary arterial hypertension in subjects who have undergone surgical repair of
other congenital heart lesions and the condition should be stabilized hemodynamically
and do not have clinically significant residual left-sided heart disease.
- Subjects with a mean pulmonary artery pressure ≥25 mmHg at rest, PCWP ≤15 mmHg, and
PVRI ≥3 Wood units x m2. If PCWP is not available, then mean LA pressure ≤15 mmHg or
LVEDP ≤15 mmHg in the absence of left atrial obstruction.
- Left-sided heart disease.
- Subjects with Down syndrome.
- Subjects with Obstructive Sleep Apnea, regardless of treatment status.
- Pericardial constriction.
- Subjects with significant (2+ for regurgitation) valvular disease other than tricuspid
or pulmonary regurgitation.
- Acutely decompensated heart failure within previous 30 days from screening.
- Subjects who have had an atrial septostomy within previous 6 months of screening.
- Subjects with hemodynamic instability or hypo- or hypertension at screening.
- Subjects with a history of stroke, myocardial infarction or life threatening
arrhythmia within 6 months of screening.
- Subjects with moderate to severe restrictive pulmonary disease (Total Lung Capacity or
Forced Vital Capacity ?60% of normal) or history of severe lung disease.
- Subjects with bronchopulmonary dysplasia (BPD) and other chronic lung diseases.
- Subjects with history of pulmonary embolism.
- Subjects with known hereditary degenerative retinal disorders (such as retinitis
pigmentosa) or history of non-arteritic anterior ischemic optic neuropathy (NAION).
- Subjects who are known to be HIV positive.
- Subjects with impairment of renal function (serum creatinine >2.5 × ULN) or hepatic
function (ALT and/or AST >3 × ULN; and/or bilirubin ?2 mg/dL). Hematological
abnormalities (e.g., severe anemia, Hgb
- Subjects with severe hepatic dysfunction (Child-Pugh classification C).
- Change in class of medication for CHF or PAH within the 10 days prior to qualifying
right heart catheterization.
- Subjects who are currently prescribed and/or taking nitrates or nitric oxide donors in
- Subjects taking chronic arginine supplementation.
- Subjects who have received parenteral inotropic medication or parenteral vasodilators
within 30 days of Day 1.
- Subjects who are receiving alpha-blockers, nicorandil, amiodarone or potent cytochrome
P450 3A4 inhibitors.
- Subjects receiving chronic treatment with off-label sildenafil within 30 days of Day 1
are excluded. Subjects receiving an endothelin antagonist?PED5 inhibitor or,
prostacyclin/prostacyclin analogue within 30 days of randomization are excluded except
- Pregnant females; breastfeeding females; males and females of childbearing potential
not using highly effective contraception or not agreeing to continue highly effective
contraception for at least 28 days after last dose of investigational product.
- Current or past illicit drug use or alcoholism excepting if abstinence can be
documented for ?1 year.
- Participation in another clinical trial of an investigational drug or device
(including placebo) within 30 days of screening for entry into the present study.
- Other severe acute or chronic medical or psychiatric condition or laboratory
abnormality that may increase the risk associated with study participation or
investigational product administration or may interfere with the interpretation of
study results and, in the judgment of the investigator, would make the subject
inappropriate for entry into this study.