Argenx’s Regulatory Milestone Offers New Hope for gMG Patients
argenx announced Friday that the U.S. Food and Drug Administration had approved VYVGART™ (efgartigimod alfa-fcab) for the treatment of generalized myasthenia gravis (gMG) in adult patients positive for anti-acetylcholine receptor (AChR) antibody. This represents 85% of the total gMG population. The news comes as an achievement for the scientific community on a whole, as VYVGART is the first-and-only neonatal Fc receptor (FcRn) blocker to be approved by the FDA.
argenx, a global immunology company, is focused on providing effective products against known but complex targets in order to treat diseases with a significant unmet medical like severe autoimmune diseases and cancer.
Generalized myasthenia gravis is a rare and chronic neuromuscular disease that causes debilitating skeletal (voluntary) muscle weakness. The voluntary muscles are responsible for controlling movements pertaining to the eyes, face, mouth, throat and limbs. In gMG, the immune system produces AChR antibodies that interfere with neuro-muscular signaling, resulting in weakness. Severe attacks of weakness can cause breathing and swallowing problems that turn fatal if not treated on time.
The approval was based on VYVGART’s strong efficacy and safety profile. There were significantly more responders on the Quantitative Myasthenia Gravis (QMG) scale following treatment with VYVGART compared with placebo (63% vs. 14%). Responders were defined as those having at least a three-point reduction on the QMG scale sustained for four or more consecutive weeks during the first treatment cycle.
VYVGART also demonstrated robust safety in the ADAPT clinical trial. The most common adverse events were respiratory tract infection (33% vs 29% in placebo), headache (32% vs 29% in placebo) and urinary tract infection (10% vs. 5% in placebo).
VYVGART is a human IgG1 antibody fragment that binds to the neonatal Fc receptor (FcRn) and effectively reduces levels of circulating immunoglobulin G (IgG) antibodies and serum AChR auto-antibody levels. The action of AChR auto-antibodies at the neuromuscular junction is a key driver of gMG. IgG antibodies are the most common antibodies found in blood and are one of the most common indicators of infection or disease in the body. They are also one of the most common therapeutic targets owing to their unique ability to link foreign particles to innate immune cells. IgG antibodies recognize antigens with high affinity and bind cellular Fc receptors with otherwise low affinity individually. These interactions occur in the form of immune complexes, resulting in high-avidity interactions.
Noting the possible impact of this regulatory milestone, Samantha Masterson, president and chief executive officer of the Myasthenia Gravis Foundation of America commented, “The gMG community has long-awaited the FDA approval of VYVGART, especially for those patients who struggle with basic personal tasks such as speaking, chewing and swallowing food, brushing teeth and hair, and in some severe cases, breathing. We thank argenx for its continued commitment to the gMG patient community, which led them to deliver this much-needed new treatment option with the potential to change the lives of many gMG patients.”
argenx is also celebrating its first commercial product approval.
“Today is the start of a new era for argenx and the gMG community as we honor our commitment to bring forward an innovative treatment option for people living with this debilitating disease,” Argenx CEO Tim Van Hauwermeiren said in a statement. “The approval of VYVGART 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.”