A phase III study designed to support use of Alexion Pharmaceuticals Inc.'s long-acting C5 complement inhibitor, Ultomiris (ravulizumab), in complement inhibitor-naïve patients with atypical hemolytic uremic syndrome (aHUS) met its primary endpoint, putting the company on track to seek FDA approval for the indication by midyear, with EU and Japanese filings to follow. Though met with skepticism in some quarters over a perceived lack of differentiation from Soliris (eculizumab), Piper Jaffray analyst Christopher Raymond said the results showed Ultomiris holding its own in patients sicker than those in an earlier Soliris trial.