Ra hopes to launch a Phase III program for zilucoplan next year, with a goal of bringing an alternative therapy for MG patients into competition with Alexion’s Soliris.

Alexion’s third deal this year brings privately held Syntimmune and its Phase Ib/IIa candidate for three IgG-mediated rare disorders, including warm autoimmune hemolytic anemia, for a $400m upfront price tag.

Switching patients from the very expensive ultra rare disorder drug to ravulizumab will be a key strategy for Alexion if the latter is approved. Recent compelling data in paroxysmal nocturnal hemoglobinuria patients suggests the long-acting C5 complement inhibitor could offer more benefit than its predecessor with more convenient dosing.