Evaluate the Efficacy, Safety and Pharmacokinetics of GSK1325760A in the Treatment of Pulmonary Arterial Hypertension

You may be eligible if

• Subjects must have a diagnosis of Pulmonary Arterial Hypertension (PAH) in clinical classification of Pulmonary Hypertension Group1
• The mean right heart catheterization parameters measured from 6 months prior to the administration of the investigational drug must meet the criteria below:
• Mean pulmonary arterial pressure (mPAP) of \>25 mmHg
• Pulmonary vascular resistance (PVR) of \>3 mmHg/L/min
• Mean pulmonary capillary wedge pressure or left ventricular end diastolic pressure of \<15 mmHg (if measurable)
• The measured six minutes walk distance (6MWD) at screening visit is in the range of =\>150m and \<=450m