Alexion Pharmaceuticals Inc. gained air time in mid-March for proving in phase III the long-acting, intravenous (I.V.) C5 complement inhibitor ALXN-1210 non-inferior to the company's own Soliris (eculizumab) in complement inhibitor treatment-naïve patients with paroxysmal nocturnal hemoglobinuria (PNH). But the company's hardly the only game in town.