FDA expands Vyvgart label to all adults with generalized MG

argenx said on May 8, 2026, that the US Food and Drug Administration approved a label expansion for Vyvgart and Vyvgart Hytrulo in generalized myasthenia gravis, broadening use from adults with anti-acetylcholine receptor antibody-positive disease to all adult patients with gMG. The expanded indication covers anti-AChR-positive, anti-MuSK-positive, anti-LRP4-positive, and triple seronegative disease, based on the phase 3 ADAPT SERON study. In that trial, argenx said efgartigimod met its primary endpoint, with a statistically significant improvement in MG-ADL score versus placebo at week 4, and showed clinically meaningful benefit across serotypes. (argenx.com)

Why it matters: For veterinary professionals tracking translational neurology and immunology, this is a notable example of precision autoimmune therapy moving beyond a narrower biomarker-defined label into a broader clinically diagnosed population. FcRn blockade was first approved in 2021 for anti-AChR-positive gMG, and the subcutaneous Hytrulo formulation followed in 2023, so this decision marks a meaningful expansion of the class in neuromuscular disease. It also reflects a regulatory shift toward including historically under-studied seronegative patients, a group argenx says represents about 20% of people with gMG. (fda.gov)

What to watch: Watch for updated FDA labeling language, payer and guideline uptake, and whether argenx can extend the franchise further through pediatric gMG work and additional MG subtypes. (argenx.com)