Argenx reported that Vyvgart Hytrulo, a subcutaneous FcRn antagonist formulation, met a key Phase 3 endpoint in immune-mediated necrotizing myopathy (IMNM), delivering rapid and sustained benefit in steroid-tapering patients. The company said results were statistically significant for IMNM, while a dermatomyositis (DM) subset showed improvement without statistical significance. The combined late-stage study evaluated improvements using the Total Improvement Score (TIS), with Argenx highlighting a mean TIS gain at 52 weeks and consistent safety compared with prior Vyvgart experience. Investor focus sharpened on the IMNM subgroup because it has limited targeted options. Analysts framed the data as a meaningful expansion lever for the Vyvgart franchise, potentially broadening label scope beyond existing myasthenia gravis and other indications.