BREATHE-1 Trial (Bosentan in PAH) Summary
Published in 2002, the BREATHE-1 trial investigated the effect of bosentan on exercise capacity in a larger number of patients with pulmonary arterial hypertension (PAH) (including patients in WHO functional class IV).
In total, 213 patients who had symptomatic, severe PAH (WHO functional class III or IV) despite treatment with anticoagulant drugs, vasodilators, diuretics, cardiac glycosides, or supplemental oxygen were randomized to receive 2 different doses of bosentan or placebo.
The primary outcome of the BREATHE-1 trial was change from base line to week 16 in exercise capacity (meters). Based on the results, patients who were treated with bosentan showed significant more exercise capacity with increase in 36 m walk capacity compared to deterioration of -8 m in the placebo group. Additionally, patients on bosentan showed significant improvement in WHO functional class compared to placebo.
The authors concluded that bosentan is beneficial in patients with pulmonary arterial hypertension and is well tolerated at a dose of 125 mg twice daily. Endothelin-receptor antagonism with oral bosentan is an effective approach to therapy for pulmonary arterial hypertension.