Pharmacokinetic/LDL‐C and exposure–response analysis of tafolecimab in Chinese hypercholesterolemia patients: Results from phase I, II, and III studies

Abstract

Abstract Tafolecimab, a novel fully human monoclonal antibody targeting PCSK9, has been assessed in Chinese healthy volunteers and patients with hypercholesterolemia. This analysis is to develop and qualify a population pharmacokinetics (PopPKs)/LDL‐C model to characterize tafolecimab PK and LDL‐C profiles, evaluate the impact of potential covariates on tafolecimab, estimate individual predicted exposure, and LDL‐C decreasing, furthermore, explore exposure–response relationship to support clinical use. Data from six clinical trials in China were used to develop the PopPK/LDL‐C model. A Michaelis–Menten approximation of the target‐mediated drug disposition (TMDD) model was used to describe PK data and indirect response (IDR) model was developed to estimate the LDL‐C profile. A stochastic approximation expectation maximization algorithm was applied to estimate PopPK/LDL‐C parameters. The PK/LDL‐C time course data for tafolecimab were well described by TMDD/IDR model. Baseline covariates resulting in statistically significant changes in PK/LDL‐C parameters included: body weight and sex on absorption rate constant; body weight, sex, and unbound PCSK9 on central volume; body weight and sex on clearance; baseline LDL‐C on first‐order rate constants for the removal of an effect); and disease and sex on maximum effect. However, the magnitudes of changes associated with these covariates do not necessitate dose adjustment. Exposure–efficacy relationship indicated that the nadir of LDL‐C reduction achieved with the steady‐state trough plasma concentration (Ctrough) of tafolecimab at 5 μg/mL, and no further LDL‐C decreasing with the increasing Ctrough. There was no exposure dependency observed in exposure‐safety exploration. The PopPK/LDL‐C model was successfully developed, validated, and predicted tafolecimab/LDL‐C concentrations and individual exposures.