This study is an international, open-label, multi-center, Phase II, multiple dose, dose-finding study to investigate the safety, tolerability and pharmacokinetic characteristics of BPS-MR tablets in male and female patients with PAH. All patients will be receiving background therapy with either a phosphodiesterase (PDE-5) inhibitor, endothelin receptor antagonist (ERA), or the combination of these two.~The study is divided into two phases:~The Treatment Phase and~The Down-Titration Phase~Screening will be conducted on an outpatient basis within 21 days prior to the Baseline visit. Patients meeting the inclusion/exclusion criteria at the Baseline visit will enter the Treatment Phase and begin taking one BPS-MR tablet (60µg) b.i.d. and escalating by one tablet b.i.d. each week to a maximum dose of 600µg (ten tablets) b.i.d. or until the patient reaches an intolerable dose.~Patients who reach an intolerable dose will be instructed to continue treatment at the previous dose, which will be considered as their individual MTD. For example, if a patient attains a full week of six BPS-MR tablets b.i.d. (360µg) but is unable to tolerate seven tablets (420µg) then the patient will return to using six tablets of BPS-MR b.i.d. (360µg) for up to an additional week of treatment. In this scenario, BPS-MR 360µg b.i.d. is the patient's MTD. Patients who do not reach an intolerable dose and tolerate the full ten weeks of BPS-MR dosing will be considered to have their individual MTD as BPS-MR 600µg b.i.d.~When patients reach their individual MTD (either at 10 weeks or earlier) they will return to the site 3-7 days after for an End of Treatment Phase assessment to be evaluated for safety and, optionally, a PK assessment. Subsequent to the End of Treatment Phase visit patients will be instructed to begin down-titration off of BPS-MR in weekly increments. However, patients may alternatively elect to continue taking BPS-MR at their MTD in a separate open-label extension study.
This study is an international, open-label, multi-center, Phase II, multiple dose, dose-finding study to investigate the safety, tolerability and pharmacokinetic characteristics of BPS-MR tablets in male and female patients with PAH.~Patients who meet the inclusion/exclusion criteria will enter the Treatment Phase at a Baseline visit. Patients will begin taking one BPS-MR tablet (60µg) twice daily (b.i.d.) escalating by one tablet b.i.d. each week to a maximum dose of 600µg (ten tablets) b.i.d or until the patient reaches their MTD. Following the achievement of the MTD, patients will be down-titrated off BPS-MR in weekly one tablet b.i.d. decrements. Patients may, alternatively, elect to continue taking the study drug at their MTD in a separate open-label extension study.