The current wave of MMN drug candidates all rely on protein engineering of antibody Fc regions — for example, argenx's NHANCE technology, used in empasiprubart, alters the antibody's interaction with FcRn to extend its half-life in the body. Different companies are also choosing to block different points in the complement cascade (C1q, C1s, or C2), each with different theoretical tradeoffs for efficacy and infection risk. This is a live, unresolved structural biology question: which complement target offers the best balance of blocking nerve damage while preserving enough immune function to fight infection.