Core Insights - The FDA has accepted a supplemental Biologics License Application (sBLA) for VYVGART (efgartigimod alfa-fcab) for treating adults with acetylcholine receptor antibody (AChR-Ab) seronegative generalized myasthenia gravis (gMG), with a target action date of May 10, 2026 [1][2] Company Overview - Argenx SE is a global immunology company focused on improving the lives of individuals suffering from severe autoimmune diseases [1][18] - The company is developing VYVGART, the first approved neonatal Fc receptor (FcRn) blocker, and is exploring its potential across various serious autoimmune diseases [18] Clinical Study Details - The sBLA is supported by data from the Phase 3 ADAPT SERON study, which demonstrated a statistically significant improvement in Myasthenia Gravis Activities of Daily Living (MG-ADL) total score compared to placebo after four weeks [2][3] - The study included 119 participants and evaluated the safety and efficacy of efgartigimod in adults with AChR-Ab seronegative gMG across multiple regions [5] Efficacy and Safety - In the overall population, patients treated with VYVGART showed a clinically meaningful improvement of 3.35 points in MG-ADL total score at week 4 [3] - VYVGART was well-tolerated, with a safety profile consistent with previous studies, and no new safety concerns were identified [4] Patient Population - Approximately 20% of gMG patients are AChR-Ab seronegative, lacking detectable antibodies against AChR, MuSK, or LRP4, and currently have no approved treatments available [7][8]