Pharmacokinetics and Pharmacodynamics of Nipocalimab Administered at Different Rates of Intravenous Infusion in Healthy Participants: Results of a Phase 1 Placebo-Controlled Single-Dose Study

Abstract

Background: Warm autoimmune hemolytic anemia (wAIHA) is a rare autoimmune condition driven by autoantibodies that can significantly impact a patient's quality of life. wAIHA is characterized by the premature destruction of red blood cells (RBCs) in the presence of autoantibodies which preferentially bind to RBCs at 37°C. There is currently no approved treatment for wAIHA. Patients with severely symptomatic anemia are typically managed with corticosteroids and rituximab, both of which are associated with potential relapse and adverse events. Nipocalimab, which is in clinical development for the treatment of wAIHA (NCT04119050), is a fully human, aglycosylated, effectorless IgG1 monoclonal antibody that targets the IgG binding site on the neonatal Fc receptor (FcRn) with high affinity to lower circulating IgG levels. This study assessed the pharmacokinetics (PK) and pharmacodynamics (PD) of single doses of nipocalimab administered at different IV infusion rates in healthy adults to support the potential use of shortened infusions in future studies. Nipocalimab was generally safe and well-tolerated at all doses and infusion rates; detailed safety results have been presented separately [Leu JH, et al. EHA 2022. Presentation P1534]. Methods: The trial was a single dose, sequential, randomized, double-blind, placebo-controlled, escalating dose and infusion rate study. Eligible participants were males or females aged 18-55 years with no clinically significant medical or physical conditions. Participants were randomized to 1 of 5 cohorts (n=8 per cohort [6 nipocalimab, 2 placebo]) to receive nipocalimab 30 mg/kg IV infused over 60, 30, 15 or 7.5 min (0.5, 1, 2, or 4 mg/kg/min), nipocalimab 60 mg/kg IV infused over 15 min (4 mg/kg/min) or matching placebo. Escalation to the next dose level was permitted following review by a safety monitoring committee. Pharmacokinetic sampling of nipocalimab was conducted predose, midpoint of infusion (MOI), end of infusion (EOI), EOI + 0.083h, EOI + 0.25h, EOI + 1h, start of infusion + 24h, Day 8, and Day 15 postdose; MOI and EOI varied for each dose. In terms of PD, total serum IgG was assessed. Results: A total of 40 participants (70% female, 93% white) received study drug, of which 30 were included in the PK analysis; 39 completed the study. Mean serum nipocalimab concentration-time profiles were similar following all 30 mg/kg doses regardless of infusion rate; mean serum concentrations were ~2 times higher following a 60 mg/kg infusion. Nipocalimab remained detectable up to ~169 hours postdose for 30 mg/kg groups and ~337 hours postdose for the 60 mg/kg group. Geometric mean peak (Cmax) and overall exposure (AUC) to nipocalimab were unaffected by infusion rate when administered at 30 mg/kg. Following a 60 mg/kg infusion, AUCs were 2.4-2.8 times higher and Cmax was 2.0-2.2 times higher than with 30 mg/kg infusions. Median Tmax was approximately at EOI following the 60 mg/kg infusion. Mean half-life (t½) values were similar in all treatment groups. In terms of total serum IgG, changes from baseline were decreased among all nipocalimab cohorts at all postdose time points. The maximum decrease in mean serum IgG levels was 79% at day 15 with nipocalimab 60 mg/kg. Conclusion: Nipocalimab Cmax and AUC were not affected by infusion rates when given at a dose of 30 mg/kg, but Tmax was delayed at the fastest infusion rates. Following the 60 mg/kg infusion, peak and overall nipocalimab exposures were 2-2.8 times higher than following 30 mg/kg infusions.