Covariate-based dose individualization of the cytotoxic drug indisulam to reduce the risk of severe myelosuppression

Aim Chemotherapy with indisulam causes myelosuppression. This study aimed to evaluate the influence of patient-related covariates on pharmacokinetics and pharmacodynamics, to identify patients at risk for severe myelosuppression and to develop a dosing algorithm for treatment optimization. Methods Pharmacokinetic and pharmacodynamic data of 412 patients were available. Non-linear mixed effects modeling was used to determine the relative risk of dose-limiting myelosuppression for various covariates (demographics, physical condition, prior treatment, comedication, CYP2C genotype and biochemistry). Results Body surface area (BSA), race and CYP2C genotype had a significant impact on indisulam elimination (P <0.001). Low BSA, Japanese race, variant CYP2C genotype, low baseline neutrophil and thrombocyte counts and female sex were clinically relevant risk factors of dose-limiting myelosuppression (RR > 1.1). A dosing strategy was developed to optimize treatment for patient subgroups. Conclusions This study has identified covariates related to an increased risk of myelosuppression after indisulam therapy. Dose individualization may contribute to treatment optimization.