Argenx's Autoimmune Myositis Treatment Meets Primary Endpoint in Late-stage Trial

01:50 AM EDT, 08/17/2026 (MT Newswires) -- Belgium-listed immunology company Argenx (ARGX.BR) said Monday that a phase 3 Alkivia trial evaluating its autoimmune myositis treatment efgartigimod met its primary endpoint. In the combined population of patients with immune-mediated necrotizing myopathy and dermatomyositis, those receiving efgartigimod showed a 15.4-point greater mean total improvement score at week 52 compared with placebo. The study also met its primary endpoint in the IMNM subgroup, while patients with dermatomyositis showed a similar magnitude of improvement that did not reach statistical significance.