Pharmacokinetics and Pharmacodynamics of Nipocalimab, a Neonatal Fc Receptor Blocker, in Healthy Japanese Volunteers

Nipocalimab is a high-affinity, fully human, effectorless immunoglobulin G1 monoclonal antibody targeting the neonatal Fc receptor and is currently under evaluation for the treatment of rare and prevalent immunoglobulin G autoantibody-mediated and alloantibody-mediated diseases. This phase I, randomized, double-blind, placebo-controlled, single-dose escalation study in healthy Japanese volunteers (N = 24) assessed the safety, pharmacokinetics, and effect on the serum immunoglobulin G level of single doses of nipocalimab. Volunteers were grouped into three cohorts and received intravenous nipocalimab at 10, 30, or 60 mg/kg or placebo. To complement the study, genetic variation in the Fcγ receptor and transporter subunit of the neonatal Fc receptor was analyzed in Japanese and diverse populations. Nipocalimab was generally safe and well tolerated at all dose levels, with three (12.5% 3/24) volunteers experiencing treatment-emergent adverse events across all nipocalimab doses. Mean serum immunoglobulin G levels decreased in a dose-dependent manner from baseline with nipocalimab treatment compared with placebo. Maximum serum nipocalimab concentrations demonstrated proportional increases with dose, while the area under the concentration-time curve was dose dependent and demonstrated non-linear increases with dose. Mean observed half-life was longer as the dose increased. Analysis of genetic variation in Fcγ receptor and transporter identified no unique Japanese variants or variants that alter amino acid sequences in or near the neonatal Fc receptor immunoglobulin G binding site targeted by nipocalimab. The comparable pharmacokinetic/pharmacodynamic profiles and highly conserved neonatal Fc receptor structure among diverse populations further support the clinical development of nipocalimab for the treatment of various immunoglobulin G autoantibody-mediated and alloantibody-mediated diseases across global sites and populations, including the Japanese population.