Population pharmacokinetics of mirvetuximab soravtansine in patients with folate receptor‐α positive ovarian cancer: The antibody–drug conjugate, payload and metabolite

Aims Mirvetuximab soravtansine is a first‐in‐class antibody–drug conjugate recently approved for the treatment of folate receptor‐α positive ovarian cancer. The aim of this study was to develop a population pharmacokinetic model to describe the concentration–time profiles of mirvetuximab soravtansine, the payload (DM4) and a metabolite (S‐methyl‐DM4). Methods Mirvetuximab soravtansine was administered intravenously from 0.15 to 7 mg/kg to 543 patients with predominantly platinum‐resistant ovarian cancer in 3 clinical studies, and the plasma drug concentrations were analysed using a nonlinear mixed‐effects modelling approach. Stepwise covariate modelling was performed to identify covariates. Results We developed a semi‐mechanistic population pharmacokinetic model that included linear and nonlinear routes for the elimination of mirvetuximab soravtansine and a target compartment for the formation and disposition of the payload and metabolite in tumour cells. The clearance and volume of the central compartment were 0.0153 L/h and 2.63 L for mirvetuximab soravtansine, 8.83 L/h and 3.67 L for DM4, and 2.04 L/h and 6.3 L for S‐methyl‐DM4, respectively. Body weight, serum albumin and age were identified as statistically significant covariates. Exposures in patients with renal or hepatic impairment and who used concomitant cytochrome P450 (CYP) 3A4 inhibitors were estimated. Conclusion There is no need for dose adjustment due to covariate effects for mirvetuximab soravtansine administered at the recommended dose of 6 mg/kg based on adjusted ideal body weight. Dose adjustment is not required for patients with mild or moderate renal impairment, mild hepatic impairment, or when concomitant weak and moderate CYP3A4 inhibitors are used.