Argenx reported a positive Phase 3 readout for Vyvgart Hytrulo (efgartigimod alfa) in immune-mediated necrotizing myopathy, a more aggressive myositis subtype with limited targeted treatment options. The subcutaneous, prefilled-syringe version met statistical significance in the study’s primary endpoint based on Total Improvement Score (TIS). Argenx said the program showed rapid and sustained benefit starting as early as week four, including steroid tapering, with efficacy driven largely by the immune-mediated necrotizing myopathy (IMNM) subset. Safety was described as consistent with prior studies, while benefit in dermatomyositis did not reach statistical significance. The result broadens the commercial case for the Vyvgart franchise by adding a potential expansion into a large-but-underdocumented unmet-need patient segment.