Pulmonary arterial hypertension outcomes upon endothelin-1 receptor antagonist switch to macitentan

OBJECTIVES: To assess whether switching patients with suboptimally controlled pulmonary arterial hypertension from bosentan or ambrisentan to macitentan would improve six-minute walk test (6MWT) distance and World Health Organization functional class. METHODS: This was a retrospective cohort analysis of 37 patients from a single center. Patients were separated into three heterogeneous treatment groups and followed for 18 months: switch group (n = 14): patients switched to macitentan from bosentan/ambrisentan; added group (n = 11): patients who began macitentan as de novo therapy (n = 5) or who added macitentan to an existing sildenafil regimen (n = 6); and control group (n = 12): patients for whom sildenafil and/or bosentan/ambrisentan therapy was unchanged. RESULTS: Mortality was observed in two patients (one each, switch and added groups). Patients in the control group had one hospital admission and 100% survival. There was significant improvement in functional class for the switch and added groups. Statistically significant improvement was observed in 6MWT distance in the added group alone. Overall, 92% of patients continued macitentan throughout the study. CONCLUSION: Macitentan was well tolerated. For bosentan/ambrisentan-treated patients with suboptimally controlled pulmonary arterial hypertension, switching to macitentan may facilitate an improvement in functional class.