ACTELION REPORTS NEW DATA ON TRACLEER

Actelion announced that initial results from the double-blind, placebo-controlled, multicenter EARLY study indicate that six months of treatment with the dual endothelin receptor antagonist Tracleer (bosentan) showed a significant reduction in pulmonary vascular resistance, a strong trend toward improved exercise capacity and a significant delay in the time to clinical worsening.

The Phase IIIb study enrolled a total of 185 pulmonary arterial hypertension (PAH) patients in 52 centers in 22 countries. EARLY was a double-blind, placebo-controlled study, which enrolled male and female patients ages 12 and over with mildly symptomatic (modified with New York Heart Association (NYHA) functional class II) PAH. Strict inclusion and exclusion criteria were applied to ensure that only mildly symptomatic patients were enrolled and the PAH status was confirmed by invasive hemodynamic assessment at baseline.

The primary objective of the study was to demonstrate that bosentan improves cardiac hemodynamics and, as subordinate, exercise capacity in mildly symptomatic PAH patients. The main secondary objective of the study was the evaluation of the effect of bosentan on time to clinical worsening. Other secondary objectives included dyspnea, NYHA class and quality of life. The study also evaluated safety and tolerability.

Treatment with Tracleer was associated with a highly significant reduction in pulmonary vascular resistance compared with placebo. Patients on Tracleer also showed a strong trend towards improvement in six-minute-walk test compared with placebo. The study met its main secondary endpoint, as treatment with Tracleer was associated with a significant delay in time to clinical worsening compared with placebo, representing a 70 percent reduction in risk. The drug's safety and tolerability profile was consistent with that observed in previous placebo-controlled clinical trials.

The company will now fully analyze the data in anticipation of planned upcoming regulatory filings worldwide to expand the Tracleer indication to include mildly symptomatic PAH patients. Tracleer -- first approved in the United States in late 2001 for PAH patients with NYHA modified functional class III and IV -- is already available in all major pharmaceutical markets worldwide.