An Open-Label Extension of BPS-MR-PAH-201 in Pulmonary Arterial Hypertension (PAH) Patients

This is an open-label study for patients who participated in the BPS-MR-PAH-201 study and have volunteered to continue treatment for PAH with BPS-MR tablets. Each patient will return to the clinic following enrollment in the study at 3, 6, and 12 months, and annually thereafter for assessment. Currently enrolled patients may be invited to participate in an optional four times daily (QID) dosing substudy of BPS-MR with total daily dose of BPS-MR achieved previously in the main study. Patients will return to the clinic for baseline visit, week 12, and then will follow the visit schedule provided to them in BPS-MR-PAH-202 main study.