Vyvgart Tx Associated with Significant Functional Benefits in Those with AChR Ab Negative Generalized Myasthenia Gravis
KEY TAKEAWAYS
- Treatment with Vyvgart significantly improved ADLs in adults with AChR-Ab-negative gMG at 4 weeks.
- Subsequent treatment cycles led to incremental improvements in ADLs during an open-label extension.
- Vyvgart was well tolerated, and no new safety signals were identified.
Results from the Phase 3 ADAPT SERON trial (NCT06298552) showed that treatment with intravenous (IV) Vyvgart (efgartigimod alfa-fcab; Argenx, Amsterdam, Netherlands) significantly improved activities of daily living (ADLs) compared with placebo in adults with anti-acetylcholine receptor antibody (AChR-Ab)–negative generalized myasthenia gravis (gMG). The results were presented at the 2026 American Academy of Neurology (AAN) Annual Meeting.
Vyvgart, a human immunoglobulin G1 (IgG1) antibody Fc fragment, reduces total IgG levels—including pathogenic autoantibodies such as muscle-specific kinase antibodies (MuSK-Ab) and low-density lipoprotein receptor-related protein 4 antibodies (LRP4-Ab)—through neonatal Fc receptor (FcRn) blockade.
ADAPT SERON enrolled 119 adult participants with a confirmed gMG diagnosis who were MuSK-Ab+ (n=40), LRP4-Ab+ (n=6), or triple seronegative (n=73). In the double-blind, placebo-controlled part A, participants were randomized 1:1 to receive 4 once-weekly infusions of 10 mg/kg Vyvgart (n=58) or placebo (n=61), followed by a 5-week follow-up period. The primary end point was the change in the Myasthenia Gravis Activities of Daily Living (MG-ADL) total score from baseline to week 4. Part B included a ≤2-year open-label extension.
Key Findings
- The change in the MG-ADL total score from baseline to week 4 was significantly greater in the Vyvgart group compared with placebo (least squares mean difference, -3.35 [90% CI, -3.98 to -2.72] vs -1.90 [90% CI, -2.51 to -1.28]; P=.0068).
- Incremental improvements in the MG-ADL total scores were observed during part B across subsequent treatment cycles in all three subgroups (MuSK-Ab+, LRP4-Ab+, and triple seronegative).
- Vyvgart was well tolerated, and no new safety signals were identified.
Source
Howard J, Vu T, Zhao C, et al. Efficacy and safety of efgartigimod in anti-acetylcholine receptor antibody-negative generalized myasthenia gravis: initial results of ADAPT SERON. Presented at: American Academy of Neurology Annual Meeting; April 18-22, 2026; Chicago, IL.