ATC Group: L04AL Neonatal fragment crystallizable receptor (FcRn) inhibitors

Efgartigimod alfa is a human IgG1 antibody fragment engineered for increased affinity to the neonatal Fc Receptor (FcRn). Efgartigimod alfa binds to FcRn, resulting in a reduction in the levels of circulating IgG including pathogenic IgG autoantibodies. Efgartigimod alfa does not affect the levels of other immunoglobulins (IgA, IgD, IgE or IgM), or those of albumin.

Nipocalimab is a human IgG1 monoclonal antibody specifically targeting the IgG Fc binding site of FcRn with high specificity and high affinity at both neutral (extracellular) and acidic pH (intracellular) resulting in the reduction of circulating IgG, including IgG autoantibodies, without affecting other immunoglobulins (IgA, IgE or IgM).

Rozanolixizumab is a humanised IgG4 monoclonal antibody that decreases serum IgG concentration by inhibiting the binding of IgG to FcRn, a receptor that under physiological conditions protects IgG from intracellular degradation and recycles IgG back to the cell surface. By the same mechanism, rozanolixizumab decreases the concentration of pathogenic IgG autoantibodies associated with generalised myasthenia gravis (gMG).