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 ( 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.


  1. FDA approves new treatment for myasthenia gravis. News release. US Food and Drug Administration. December 17, 2021. Accessed December 20, 2021.
  2. 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.
  3. Vyvgart. Package insert. argenx SE; 2021. Accessed December 20, 2021.