Argenx reported a Phase 3 win for Vyvgart Hytrulo, a subcutaneous FcRn antagonist version of its blockbuster efgartigimod alfa, in immune-mediated necrotizing myopathy. The company said the drug reached statistical significance in at least one key myositis subgroup after top-line results from a late-stage combined study. In the trial, Argenx highlighted improvements on total improvement score (TIS), including rapid and sustained benefits and steroid tapering over time. The company noted that efficacy signals were stronger in immune-mediated necrotizing myopathy (IMNM) than in dermatomyositis (DM), where investigators said statistical significance was not achieved. The readout extends the Vyvgart franchise into a broader autoimmune myositis setting and is likely to intensify competition among FcRn and other immune-modulating platforms targeting rare muscle diseases with limited options.