- Subjects with PAH (i.e. IPAH or secondary to connective tissue disease or with
surgical repair of ASD, VSD, PDA, aorto-pulmonary window) whose baseline six minute
walk test distance is >/= 100 m and = 450 m.
- Subjects with a mean pulmonary artery pressure of >/= 25 mmHg and a pulmonary artery
wedge pressure of = 15 mmHg at rest via right heart catheterization performed within
12 weeks prior to randomization.
- Subjects whose 6 Minute Walk Distance may be limited by conditions other than PAH
related dyspnoea or fatigue, e.g. claudication from vascular insufficiency or
significant arthritis.
- Subjects who are currently receiving any forms of chronic treatment for PAH such as
prostacyclin, PDE-5 inhibitors, endothelin-receptor antagonists, nitrates or nitric
oxide donors (e.g. arginine supplement, nicorandil) in any form, protease inhibitors
such as ritonavir and saquinavir, ketoconazole, itraconazole, and alpha blockers.
Subjects previously receiving any of these drugs must have stopped use for a period of
at least 1 month prior to screening, except in the case of bosentan or prostacyclin (3
months).