The Food and Drug Administration (FDA) has approved Vyvgart™ (efgartigimod alfa-fcab) for the treatment of generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) antibody positive.
Vyvgart is a neonatal Fc receptor antagonist designed to reduce immunoglobulin G (IgG) antibody levels and block the IgG recycling process. The application is supported by data from the multicenter, randomized, double-blind phase 3 ADAPT trial (ClinicalTrials.gov: NCT03669588) that evaluated the efficacy and safety of efgartigimod in 167 adults with gMG. Patients were randomly assigned 1:1 to receive efgartigimod 10mg/kg via intravenous infusion or placebo.
The primary endpoint was the percentage of responders on the Myasthenia Gravis Activities of Daily Living (MG-ADL) score among acetylcholine receptor-antibody positive (AChR-Ab+) generalized myasthenia gravis patients. Responders were defined as having at least a 2-point improvement on the MG-ADL score for at least 4 consecutive weeks.
Findings showed that a significantly greater proportion of AChR-Ab+ patients treated with efgartigimod met the primary end point compared with placebo (67.7% vs 29.7%, respectively; P <.0001). Additionally, a greater proportion of efgartigimod-treated AChR-Ab+ patients responded on the Quantitative Myasthenia Gravis (QMG) score compared with placebo (63.1% vs 14.1%, respectively; P <.0001); a responder was defined as having at least a 3-point improvement for at least 4 consecutive weeks.
The most common adverse reactions reported with efgartigimod were respiratory tract infections, headache, and urinary tract infection.
Vyvgart is supplied as a 20mL single-dose vial containing 400mg of efgartigimod alfa-fcab for intravenous infusion after dilution.
“The approval of Vygart represents many achievements: our first approved product; the first-and-only FDA-approved neonatal Fc receptor blocker; and the first approved therapy designed to reduce pathogenic IgGs, an underlying driver of gMG,” said Tim Van Hauwermeiren, Chief Executive Officer of argenx.
The Company will be launching a patient assistance program called My Vyvgart Path.
- FDA approves new treatment for myasthenia gravis. News release. US Food and Drug Administration. December 17, 2021. Accessed December 20, 2021. https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-myasthenia-gravis.
- argenx announces US Food and Drug Administration (FDA) approval of Vyvgart™ (efgartigimod alfa-fcab) in generalized myasthenia gravis. News release. argenx SE. December 17, 2021. Accessed December 20, 2021. https://www.businesswire.com/news/home/20211217005641/en/argenx-Announces-U.S.-Food-and-Drug-Administration-FDA-Approval-of-VYVGART%E2%84%A2-efgartigimod-alfa-fcab-in-Generalized-Myasthenia-Gravis.
- Vyvgart. Package insert. argenx SE; 2021. Accessed December 20, 2021. https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/761195s000lbl.pdf.