Tadalafil for the Treatment of Pulmonary Arterial Hypertension: A Double-Blind 52-Week Uncontrolled Extension Study

Study Questions:

What is the long-term safety and durability of efficacy of tadalafil for patients with pulmonary arterial hypertension (PAH) enrolled in the extension of the PHIRST (Pulmonary Arterial Hypertension and Response to Tadalafil) study?