FDA Grants Priority Review to argenx for VYVGART Label Expansion
Immunology company argenx announces that the U.S. Food and Drug Administration has agreed to prioritize the review of a supplemental indication for its VYVGART treatment in seronegative generalized myasthenia. The FDA has set a target decision date of May 10, 2026, according to the press release.
Priority Review Status Granted
The FDA has granted priority review status to the supplemental biologics license application (sBLA) for VYVGART (efgartigimod alfa-fcab) in the treatment of adults with seronegative generalized myasthenia (gMG) to acetylcholine receptor antibodies (AChR-Ab), the company states. This expedited process reflects, according to argenx, the drug's potential to meet an unmet medical need for these patients who have limited therapeutic options. The target action date set by the FDA under the Prescription Drug User Fee Act (PDUFA) is May 10, 2026. VYVGART is already approved in the United States, European Union, China, and Canada for adults with seropositive gMG to anti-AChR antibodies, the press release specifies.
Supporting Data from Phase 3 Study
The application is supported by data from the phase 3 ADAPT SERON study, which assessed the efficacy and safety of VYVGART in adults with seronegative gMG to AChR-Ab antibodies, including the three subtypes: MuSK+, LRP4+, and triple seronegative. The study met its primary endpoint with a p-value of 0.0068, demonstrating a statistically significant improvement in the total Myasthenia Gravis Activities of Daily Living (MG-ADL) score compared to placebo after four weeks, according to the group. In the overall population, the mean change from baseline in patients treated with VYVGART was a clinically significant improvement of 3.35 points in the total MG-ADL score at week 4. Improvements in MG-ADL and QMG (Quantitative Myasthenia Gravis) scores were observed during subsequent treatment cycles in the overall population and in all patient subgroups, the company indicates.
Safety Profile of VYVGART
VYVGART was well tolerated with a safety profile consistent with that established in patients with seropositive gMG to AChR-Ab antibodies and in other indications, according to the press release. No new safety issues were identified during the study. The ADAPT SERON study, a randomized, double-blind, placebo-controlled trial, included 119 adults with seronegative gMG to AChR-Ab antibodies across North America, Europe, China, and the Middle East. Participants had a confirmed diagnosis of myasthenia by an independent expert panel and a total MG-ADL score of 5 or more. Currently, there are no approved treatments for patients with anti-LRP4 antibodies or for triple seronegative patients, argenx reminds.
