ACE2 and pulmonary arterial hypertension: This Phase IIa, multi‐center, open‐label, exploratory, single‐dose, dose‐escalation study (NCT03177603) assessed the potential vasodilatory effects of single doses of GSK2586881 (a recombinant human ACE2) on acute cardiopulmonary hemodynamics in hemodynamically stable adults with documented PAH who were receiving background PAH therapy.