Neonatal Fc receptors (FcRn) prevent the degradation of immunoglobulins G (IgG), promoting their recycling. Nipocalimab is a monoclonal antibody directed against FcRn giving hope for a drop in the serum IgG level and therefore a reduction in circulating autoantibodies in various autoimmune diseases.
Biological and clinical benefits
Developed by Momenta Pharmaceuticals, a biotech acquired by Johnson & Johnson in August 2020, nipocalimab received orphan drug status from US health authorities in 2019 for autoimmune hemolytic anemia. The same year began the international phase II trial Vivacity-MG, to evaluate the drug candidate in myasthenia gravis, a pathology in which antibodies (anti-RACh, anti-MuSK, etc.) directed against the neuromuscular junction alter its operation.
Vivacity-MG included 68 adults with generalized myasthenia gravis inadequately responding to usual treatments, and tested against placebo for eight weeks four different doses of nipocalimab, infused every two weeks. Its results, released at the American Academy of Neurology (AAN) meeting, show that the drug candidate:
- is well tolerated, with an incidence of infections and headaches comparable to that of placebo;
- causes a rapid and significant reduction in total serum IgG and anti-RACh IgG, correlated with an improvement in the MG-ADL score;
- results in, at all doses, a mean decrease in the MG-ADL score greater than that of placebo (significant difference) after eight weeks of treatment;
- rapidly improves, more often than placebo, the MG-ADL score (within two weeks) and sustainably (51.9% vs. 15.4%).
