FDA Approves Argenx’s Vyvgart to Treat MG

The U.S. Food and Drug Administration (FDA) has approved Vyvgart (efgartigi-mod) to treat generalized myasthenia gravis (gMG) in adults who test positive for the anti-acetylcholine receptor (AChR) antibody. In MG, the immune system produces AChR antibodies that interfere with communication between nerves and muscles, resulting in weakness. Severe attacks of weakness can cause breathing and swallowing problems that can be life-threatening.

Vyvgart is the first approval of a new class of medication. It is an antibody fragment that binds to the neonatal Fc receptor (FcRn), preventing FcRn from recycling immunoglobulin G (IgG) back into the blood. The medication causes a reduction in overall levels of IgG, including the abnormal AChR antibodies present in MG.

The safety and efficacy of Vyvgart were evaluated in a 26-week clinical study of 167 patients with MG who were randomized to receive either Vyvgart or placebo. The study showed that more patients with MG with antibodies responded to treatment during the first cycle of Vyvgart (68 percent) compared to those who received placebo (30 percent) on a measure that assesses the impact of MG on daily function. More patients receiving Vyvgart also demonstrated response on a measure of muscle weakness compared to placebo.

The most common side effects associated with the use of Vyvgart include respiratory tract infections, headache and urinary tract infections. Since Vyvgart causes a reduction in IgG levels, the risk of infections may increase. Hypersensitivity reactions such as eyelid swelling, shortness of breath and rash have occurred.