The study evaluated the efficacy and safety of the 10mg dose of macitentan or placebo in 178 patients with idiopathic pulmonary fibrosis.
On average, patients were exposed to study drug for more than 14 months, with a maximum exposure of 24.6 months.
The dual endothelin receptor antagonist macitentan in this patient population was generally well tolerated.
There was no difference in liver enzyme elevations between macitentan and placebo.
Actelion CEO Jean-Paul Clozel said the 10 mg dose of macitentan is the higher of two doses under evaluation in their ongoing Phase III SERAPHIN study in pulmonary arterial hypertension.
"I expect this event-driven morbidity/mortality study with over 740 patients to report in the first half of 2012," Clozel said.