Population PK/PD Modeling and Simulation to Predict the Comparative Long-Term Efficacy of Olokizumab in Rheumatoid Arthritis Patients

Background/Objectives: Olokizumab (OKZ) is a humanized monoclonal antibody targeting interleukin-6 (IL-6). OKZ demonstrated efficacy in subjects with active rheumatoid arthritis (RA) in randomized controlled trials versus adalimumab (ADLM) and placebo over 24 weeks, with sustained efficacy confirmed through 106 weeks in an open-label single-arm extension study (OLE). This analysis aimed to predict 1-year efficacy of OKZ 64 mg administered every two weeks (q2w) and every four weeks (q4w) compared with ADLM and placebo through virtual clinical trial simulations based on population pharmacokinetic/pharmacodynamic (PK/PD) models.

Methods

Nonlinear mixed-effects models were developed using pooled data from phase III studies. Turnover models with a maximum inhibition Imax-type relationship between OKZ concentrations and clinical scores were applied. Simulated clinical trials were performed to estimate 52-week response rates, defined as proportions of patients achieving low disease activity (DAS28-CRP ≤ 3.2) and remission (CDAI ≤ 2.8). The reliability of the simulated extrapolations was validated against published data.