Tracleer fails Phase IV study evaluating mortality in PAH patients - Actelion

Actelion Ltd announced the results of COMPASS-2, a Phase IV, prospective, randomized, double-blind, placebo-controlled, event-driven study evaluating the effect of Tracleer (bosentan) on the time to first morbidity or mortality event in patients with symptomatic Pulmonary Arterial Hypertension (PAH) already treated with sildenafil. COMPASS-2 did not meet the primary endpoint of time to first morbidity or mortality event; bosentan showed a risk reduction of 17% versus placebo (p=0.25). In an exploratory analysis, bosentan on top of sildenafil showed an improvement of 21.8 meters in 6MWD at week 16 (p=0.01). The well characterized safety profile of bosentan was confirmed and a placebo-corrected incidence of 15.4% in liver enzyme elevations (aspartate aminotransferase (AST) or alanine aminotransferase (ALT)) greater than three times the upper limit of normal was observed over a median exposure to double-blind treatment of 23 months.

The patent for Tracleer expires in 2015 and a positive result in the trial could have benefitted Tracleer generics and made them more effective competition to the Tracleer successor at Actelion which is Opsumit.