Selexipag (ACT-293987) in Pulmonary Arterial Hypertension

Inclusion Criteria:

- Male and female patients 18-75 years old, with symptomatic PAH

- PAH belonging to the following subgroups of the updated Dana Point Clinical
Classification Group 1 (Idiopathic, or Heritable, or Drug or toxin induced, or
Associated (APAH) with Connective tissue disease, Congenital heart disease with simple
systemic-to-pulmonary shunt at least 1 year after surgical repair, or HIV infection)

- Documented hemodynamic diagnosis of PAH by right heart catheterization, performed at
any time prior to Screening

- Six minute walk distance (6MWD) between 50 and 450 m at Screening within 2 weeks prior
to the Baseline Visit

- Signed informed consent

Exclusion Criteria:

- Patients with pulmonary hypertension (PH) in the Updated Dana Point Classification
Groups 2-5, and PAH Group 1 subgroups that are not covered by the inclusion criteria

- Patients who have received prostacyclin or its analogs within 1 month before Baseline
Visit, or are scheduled to receive any of these compounds during the trial

- Patients with moderate or severe obstructive lung disease

- Patients with moderate or severe restrictive lung disease

- Patients with moderate or severe hepatic impairment (Child-Pugh B and C)

- Patients with documented left ventricular dysfunction

- Patients with severe renal insufficiency

- Patients with BMI <18.5 Kg/m2

- Patients who are receiving or have been receiving any investigational drugs within 1
month before the Baseline Visit

- Acute or chronic impairment (other than dyspnea), limiting the ability to comply with
study requirements, in particular with 6MWT

- Recently conducted or planned cardio-pulmonary rehabilitation program based on
exercise training

- Psychotic, addictive or other disorder limiting the ability to provide informed
consent or to comply with study requirements

- Life expectancy less than 12 months

- Females who are lactating or pregnant or plan to become pregnant during the study

- Known hypersensitivity to any of the excipients of the drug formulations