Argenx Plans FDA Label Expansion for Vyvgart Following Successful Trial Results

Argenx has announced positive topline data from the Phase 3 ADAPT SERON study of Vyvgart (IV: efgartigimod alfa-fcab) for adult patients with generalized myasthenia gravis. The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in MG-ADL total score compared to placebo. The company plans to submit a supplemental marketing application to the FDA by the end of 2025, seeking expansion of the Vyvgart label to include adult AChR-Ab seronegative gMG patients across all three subtypes.

Argenx SE has announced positive topline data from the Phase 3 ADAPT SERON study of Vyvgart (IV: efgartigimod alfa-fcab) for adult patients with generalized myasthenia gravis (gMG). The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in MG-ADL (Myasthenia Gravis Activities of Daily Living) total score compared to placebo. The company plans to submit a supplemental marketing application (sBLA) to the FDA by the end of 2025, seeking expansion of the Vyvgart label to include adult AChR-Ab seronegative gMG patients across all three subtypes—MuSK+, LRP4+, and triple seronegative.

The ADAPT SERON study was a randomized, double-blind, placebo-controlled, multi-center trial evaluating the safety and efficacy of efgartigimod in adults with AChR-Ab seronegative gMG (n=119) across North America, Europe, China, and the Middle East. The study met its primary endpoint with a p-value of 0.0068, showing that patients treated with Vyvgart experienced a statistically significant and clinically meaningful improvement in MG-ADL total score compared to placebo.

Vyvgart was well tolerated and safe across all AChR-Ab seronegative subtypes, consistent with its established safety profile in patients with AChR-Ab seropositive gMG and other indications. No new safety concerns were identified.

The study's principal investigator, James F. Howard Jr., M.D., highlighted the significance of the results, stating, "The results of the ADAPT SERON study confirm that Vyvgart has the potential to be a targeted, effective, and safe treatment for patients living with gMG, regardless of autoantibody status." Luc Truyen, M.D. Ph.D., Chief Medical Officer at Argenx, added, "The positive outcome of the ADAPT SERON study demonstrates Vyvgart’s ability to provide meaningful benefit across all AChR-ab seronegative gMG subtypes."

The Phase 3 ADAPT SERON study was designed to evaluate the safety and efficacy of efgartigimod in adults with AChR-Ab seronegative gMG. The primary endpoint was the MG-ADL total score change from baseline to day 29. Enrolled participants had a confirmed MG diagnosis by an independent panel of experts and an MG-ADL total score of 5 or greater. Participants were on a stable dose of at least one gMG treatment prior to randomization.

About 20% of patients with gMG are AChR-Ab seronegative, including those with detectable autoantibodies targeting other NMJ proteins such as MuSK and LRP4, or those who are triple seronegative. Currently, there are no approved treatments available for patients with anti-LRP4 antibodies or for triple seronegative patients. The results from the ADAPT SERON study represent a significant advancement in the management of this debilitating and unpredictable disease for patients with limited treatment options.

Argenx's commitment to the MG community and its ambition to help as many MG patients as possible are evident in the company's longstanding dedication to developing effective treatments for gMG.

References:
[1] https://www.marketscreener.com/news/argenx-se-announces-positive-topline-results-from-adapt-seron-study-of-vyvgart-in-patients-with-achr-ce7c50dbd08ff626
[2] https://www.nasdaq.com/articles/argenxs-vyvgart-achieves-primary-endpoint-pivotal-study-achr-ab-seronegative-gmg
[3] https://finance.yahoo.com/news/argenx-announces-positive-topline-results-050000095.html