Population pharmacokinetic analysis of bevacizumab in Japanese cancer patients with proteinuria: a prospective cohort study.

Purpose: Bevacizumab (BV) is an effective therapeutic antibody utilized in various cancers. Serum BV concentration can be a factor that potentially affects its therapeutic efficacy. Although proteinuria could affect BV pharmacokinetics, its influence was not evaluated in the previous population pharmacokinetic (PopPK) studies. Because BV can cause proteinuria as an adverse event, the present study aimed to develop a PopPK model in patients with proteinuria and to evaluate the influence of proteinuria on BV pharmacokinetics.

Methods: This prospective cohort study enrolled 70 Japanese cancer patients newly starting BV, and 368 concentration samples from these patients were analyzed. Serum BV concentrations were measured at several time points including at the onset of proteinuria. PopPK analysis was conducted using a non-linear mixed-effects modeling program. A two-compartment model was used to estimate total body clearance (CL).

Results: Serum BV concentrations divided by the dose per body weight and dosing interval tended to be lower in patients with higher urinary protein to creatinine ratio (UPCR). The covariate analysis showed that increasing BV CL was associated with decreasing serum albumin concentration and increasing body weight and UPCR. The simulated median trough concentrations of BV in patients with Common Terminology Criteria for Adverse Events grades 1, 2, and 3 proteinuria were decreased by 12.0%, 20.6%, and 31.5%, respectively, compared to those in patients with grade 0.

Conclusion: We successfully established a PopPK model incorporating UPCR to predict serum BV concentrations in patients with proteinuria. Our study provides additional insights to better understand BV pharmacokinetics.