Actelion Ltd ATLN.VX Monday said a late-clinical study of its hypertension drug macitentan has met its primary end point, and it will seek global registration of the remedy by the fourth quarter of the year. The approval of macitentan is seen as key for Actelion’s future as the company stands to lose the patent protection of its key drug, Tracleer for pulmonary hypertension, in 2015. Tracleer makes up the bulk of Actelion’s revenue but competition from generic products, once the drug loses its patent, could cut more than 50% of the medicine’s revenue, analysts say.