Argenx Prepares FDA Filing to Expand Vyvgart Use in Myasthenia Gravis After Late-Stage Trial Win on August 25, 2025 Approved Argenx Myasthenia Gravis Myasthenia Gravis, Generalized Polyradiculoneuropathy, Chronic Inflammatory Demyelinating Self-injection Syringes United States Food and Drug Administration Vyvgart +