Actelion's macitentan meets primary endpoint in pivotal Phase III PAH study

Europe’s largest biotech company, Actelion (SIX: ATLN), says that initial analysis indicates that the pivotal, long-term, event-driven study SERAPHIN with macitentan, a novel dual endothelin receptor antagonist, in 742 patients suffering from pulmonary arterial hypertension (PAH) and treated for up to three and a half years, has met its primary endpoint. The news pushed Actelion’s share price up 18% to 39.98 Swiss francs by midday yesterday, having jumped as much as 23% earlier.

Macitentan, at both the 3mg and 10mg dose, decreased the risk of a morbidity/mortality event over the treatment period versus placebo. This risk was reduced by 45 percent in the 10mg dose group (p<0.0001). At 3mg, the observed risk reduction was 30% (p=0.0108). Treatment with macitentan in the SERAPHIN study was well tolerated.

Health care advisory firm Decision Resources forecasts that macitentan will earn a 20% patient share in the US PAH market by 2019, owing to its positive morbidity/mortality data, superior safety profile and lower risk of causing drug interactions compared with the current market leader, Actelion’s Tracleer (bosentan), which loses patent protection in 2015. The success of macitentan is seen as crucial for Actelion to maintain its leadership of the PAH market.