Vyvgart/Vyvgart Hytrulo Label Expanded to Include Those with AChR-Negative gMG

The label for Vyvgart (efgartigimod alfa-fcab; Argenx, Amsterdam, the Netherlands) and Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase-qvfc; argenx, the Netherlands) for the treatment of adults with generalized myasthenia gravis (gMG) was expanded in a new Food and Drug Administration (FDA) decision. In addition to anti-acetylcholine receptor antibody–positive (AChR+) gMG, the updated indication now includes AChR-negative (AChR–) serotypes: anti–muscle-specific kinase antibody–positive (MuSK+), anti-low-density lipoprotein receptor–related protein 4 antibody–positive (LRP4+), and triple-seronegative disease.

The approval was based on results from the phase 3 ADAPT SERON study (NCT06298552), which evaluated Vyvgart treatment in adults with AChR– gMG. According to a statement released by Argenx, approximately 20% of individuals with gMG do not have detectable anti-AChR antibodies, a group that has historically been underrepresented in clinical trials.

ADAPT SERON was a randomized, double-blind, placebo-controlled, multicenter study that included 119 adults across North America, Europe, China, and the Middle East. In Part A, participants were randomized 1:1 to receive 4 once-weekly intravenous infusions of Vyvgart or placebo, followed by 5 weeks of follow-up. Participants had confirmed myasthenia gravis diagnosis by an independent expert panel, Myasthenia Gravis Activities of Daily Living (MG-ADL) total score ≥5, and stable background gMG therapy before randomization.

Key Findings

• The study met its primary end point, with Vyvgart-treated participants demonstrating statistically significant improvement in MG-ADL total score vs placebo at week 4 (P=.0068).
• In the overall AChR– study population, Vyvgart treatment was associated with a mean 3.35-point improvement from baseline in MG-ADL total score at week 4.
• Improvements in MG-ADL and Quantitative Myasthenia Gravis (QMG) scores were observed across subsequent treatment cycles and across the serotypes studied.
• Vyvgart was well tolerated across serotypes, with safety consistent with its established profile in AChR+.

Vyvgart is now available for adult gMG patients across antibody-defined subgroups, including those without detectable AChR antibodies. The company also noted that Vyvgart is available in 3 administration options, including Vyvgart Hytrulo self-injection with a prefilled syringe.

Source

Argenx. Argenx announces U.S. FDA approval expanding Vyvgart and Vyvgart Hytrulo for use in all adult patients living with gMG. Published May 8, 2026. Accessed May 12, 2026. https://argenx.com/news/2026/press-release-3291372