Phase 1/1b Study With Nab-sirolimus for Patients With Severe Pulmonary Arterial Hypertension

nab-Sirolimus, an mTOR inhibitor, is a novel formulation of albumin-bound sirolimus nanoparticles and has produced encouraging results in oncology at doses up to 100 mg/m2 given once weekly IV. This study is aimed to determine the optimal clinial dose of once weekly IV nab-sirolimus in patients with PAH and safety of 16 weeks of therapy (Phase 1, Dose finding Safety Part) followed optionally by up to 32 weeks of therapy (Extension Part).