The aim of this study is to demonstrate that clazosentan, administered as a continuous intravenous infusion at either 5 mg/h or 15 mg/h until Day 14 post aneurysmal subarachnoid hemorrhage (aSAH), reduces the incidence of cerebral vasospasm-related morbidity and all-cause mortality within 6 weeks post-aSAH treated by endovascular coiling.