Actelion announced that the FDA has officially accepted the New Drug Application (NDA) for macitentan (Opsumit) for the treatment of patients with pulmonary arterial hypertension. Macitentan is a novel dual endothelin receptor antagonist.

Opsumit was studied in the pivotal, long-term, event-driven Phase 3 outcome study, SERAPHIN, in which 742 patients suffering from pulmonary arterial hypertension were randomized to receive either placebo or macitentan at 3mg or 10mg once daily. Treatment with macitentan has demonstrated a reduction in the risk of morbidity and mortality event over the treatment period vs. placebo. This risk was reduced by 45% for patients in the 10mg dose group (P<0.0001). The observed risk reduction was 30% (P=0.0108) for patients receiving the 3mg dose.

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