Argenx said its subcutaneous FcRn antagonist Vyvgart Hytrulo hit a Phase 3 endpoint in a late-stage combined study of immune-mediated necrotizing myopathy (IMNM), a myositis subtype with limited targeted options. The company reported rapid and sustained benefit starting as early as week four and framed the program as steroid-sparing. In the trial, Vyvgart showed improvements on the Total Improvement Score (TIS) at 52 weeks versus placebo, with results particularly driven by the IMNM subgroup. Argenx also reported that a dermatomyositis (DM) subset showed meaningful improvements but did not reach statistical significance. Separate reporting indicates that investors have been quick to reprice the opportunity: one analyst characterized the readout as an expansion path for the Vyvgart franchise, especially in IMNM where currently no approved targeted therapy exists. Argenx will now move toward the regulatory and label-expansion pathway consistent with the Phase 3 dataset.