Population Pharmacokinetic and Exposure-Response Model Simulations: Predicted Exposure and Efficacy for Maintenance Doses of Intravenous Golimumab Every 6 or 8 Weeks in Patients With Moderately to Severely Active Rheumatoid Arthritis.

PURPOSE: Golimumab is approved to treat moderate-to-severe active rheumatoid arthritis when given intravenously at weeks 0 and 4, then every 8 weeks (Q8W) with concomitant methotrexate. These analyses assessed whether a shorter dosing interval could ameliorate diminished efficacy experienced by a small proportion of patients toward the end of the dosing interval. METHODS: Population pharmacokinetic and exposure-response modeling simulations were performed for intravenous golimumab 2 mg/kg at weeks 0 and 4, then Q8W or every 6 weeks (Q6W) through 1 year. A 2-compartment pharmacokinetic model with linear clearance developed based on GO-FURTHER (A Multicenter, Randomized, Double-blind, Placebo-controlled Trial of Golimumab, an Anti-TNFα Monoclonal Antibody, Administered Intravenously, in Patients With Active Rheumatoid Arthritis Despite Methotrexate Therapy) study data was used for pharmacokinetic simulations. A latent-variable indirect exposure-response model developed based on GO-FURTHER American College of Rheumatology (ACR) 20%/50%/70% improvement (ACR20, ACR50, and ACR70, respectively) data was used to predict clinical endpoints of ACR20/ACR50/ACR70 response rates. FINDINGS: For Q6W and Q8W dosing, respectively, predicted median golimumab steady-state trough (Ctrough,ss) concentrations were 0.57 and 0.24 µg/mL, and Cmax at steady state values were 33.1 and 32.9 µg/mL. Predicted peak median ACR20 steady-state response rates were 76.7% (Q6W) and 75.6% (Q8W). Predicted median ACR20 response rates at Ctrough,ss increased by 4.7 percentage points with Q6W (73.7%) versus Q8W (69.0%) dosing. Greater improvement in ACR20 response rates at trough time points was predicted in patients with lower golimumab trough serum concentrations. Consistent findings were observed for ACR50/ACR70 response rates. IMPLICATIONS: These simulations suggest that intravenous golimumab Q6W dosing increases golimumab Ctrough,ss, which may improve clinical response in the small proportion of patients with rheumatoid arthritis with waning efficacy at the end of the standard dosing interval. CLINICALTRIALS: gov identifier: NCT00973479. Clinicaltrialsregister.eu: EudraCT 2008-006064-11.