Efgartigimod alfa, sold under the brand name Vyvgart, is a medication used to treat myasthenia gravis.
Routes of administration Intravenous
Drug class Neonatal Fc receptor blocker
It is an antibody fragment that binds to the neonatal Fc receptor (FcRn), preventing FcRn from recycling immunoglobulin G (IgG) back into the blood.
When this binding occurs, the IgG recycling process is blocked.
The amount of circulating IgG decreases and therefore prevents the acetylcholine receptors from being degraded by the autoantibodies that are responsible for the myasthenia gravis.
The medication causes a reduction in overall levels of IgG, including the abnormal acetylcholine receptor (AChR) antibodies that are present in myasthenia gravis.
The most common side effects include respiratory tract infections, headache, urinary tract infections, and paresthesia.
Consider to be a first-in-class medication.
Efgartigimod alfa is indicated for the treatment of generalized myasthenia gravis in adults who are anti-acetylcholine receptor antibody positive.
In a 26-week clinical study of 167 participants with myasthenia gravis who were randomized to receive either efgartigimod alfa or placebo: more participants with myasthenia gravis with antibodies responded to treatment during the first cycle of efgartigimod alfa (68%) compared to those who received placebo (30%) on a measure that assesses the impact of myasthenia gravis on daily function.
More participants receiving efgartigimod alfa also demonstrated response on a measure of muscle weakness compared to placebo.
It is also under examination for the treatment of primary membranous nephropathy, idiopathic inflammatory myopathy (IIM), anti-neutrophil cytoplasmic antibody-associated vasculitis (ANCA Vasculitis), Graves’’ ophthalmopathy, antibody-mediated rejection (AMR), immune-mediated necrotizing myopathy, anti-synthetase syndrome, dermatomyositis, polymyositis, immune thrombocytopenia, primary Sjögren’s syndrome, rheumatoid arthritis and pemphigus.
The drug is mainly metabolized via proteolytic enzymes, and its termination half-life is 80 to 120 hours.
Side effects of efgartigimod alfa include respiratory tract infections, headache, urinary tract infection, numbness and tingling and muscle pain.