Argenx SE (NASDAQ:ARGX) shares are in focus after the U.S. Food and Drug Administration accepted a supplemental Biologics License Application for Vyvgart with Priority Review, potentially expanding the drug's reach to a difficult-to-treat subset of patients with generalized myasthenia gravis (gMG).
The application seeks approval for adults with acetylcholine receptor antibody (AChR-Ab) seronegative gMG, a group that represents approximately 20% of the total gMG population and currently faces limited therapeutic options.
The FDA has set a PDUFA target action date of May 10, 2026.
The submission is anchored by data from the Phase 3 ADAPT SERON trial, which enrolled 119 participants.
The study met its primary endpoint with high statistical significance (p=0.0068), demonstrating a mean improvement of 3.35 points on the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale at week four, compared to those receiving a placebo.
Beyond the primary results, Argenx reported consistent efficacy signals across multiple seronegative subgroups, including those positive for MuSK and LRP4 antibodies, as well as triple-seronegative patients.
The safety profile observed in the trial remained consistent with Vyvgart’s established record, with no new safety signals identified.
If approved, the expansion would solidify Vyvgart’s position as a cornerstone therapy in the gMG market, where it is already a leading biologic for seropositive patients.