6 MWD was the distance that a participant could walk in 6 minutes. Participants were asked to perform the test at a pace that was comfortable to them, with as many breaks as they needed. Continuous pulse oximetry was conducted during the test for safety. Change is Week 12 results minus baseline results.

Intent to treat population (ITT): all participants who were randomized; missing value at Week 12 imputed with last non-missing value, including the non-missing value obtained at early termination based on last observation carried forward (LOCF)

WHO functional classification for PAH ranges from Class I (no limitation in physical activity, no dyspnea with normal activity) to Class IV (cannot perform a physical activity without any symptoms, dyspnea at rest). Improvement = reduction in functional class, deterioration = increase in functional class, no change = no change in functional class.

ITT; N=number of participants with analyzable data; n=number of participants with analyzable data at the specific time point

TTCW defined as the number of days between first dose of study drug and the occurrence of a predefined clinical worsening event. Predefined clinical worsening events included: hospitalization for worsening PAH, on-study death, heart-lung or lung transplant, atrial septostomy or withdrawal due to the addition of any chronic medications for the treatment of worsening PAH.

ITT; N=number of participants with analyzable data