Efgartigimod alfa - the importance of FcRn blockade in the treatment of generalized myasthenia gravis
Abstract
Inhibitor of neonatal Fc receptors (FcRn), efgartigimod alfa, is indicated as an adjunctive therapy to standard treatment for adult patients with generalized myasthenia gravis and positivity of antibodies against acetylcholine receptors (AChR). IgG antibodies bound to FcRn escape lysosomal degradation and return to circulation.
Efgartigimod alfa is a naturally occurring FcRn ligand modified to bind to it with higher affinity. By blocking FcRn, the concentration of autoreactive IgG antibodies in serum decreases, while the treatment does not affect the levels of other immunoglobulins (IgA, IgD, IgE, or IgM) or albumin levels.
In the ADAPT clinical trial, 68% of patients treated with efgartigimod alfa achieved the primary endpoint, which was defined as a reduction of at least 2 points in the MG-ADL score one week after the fourth infusion, which was sustained for at least 4 consecutive weeks.