Evaluation of a formula for individual dosage of nedaplatin based on renal function

Purpose: Nedaplatin (NDP), a platinum derivative, has been developed to reduce nephrotoxicity and gastrointestinal toxicity of cisplatin. The pharmacokinetic profile of NDP is similar to that of carboplatin (CBDCA). The optimal dosing for CBDCA is determined by the area under the curve (AUC) using Calvert's formula. However, the administration dose of nedaplatin (NDP) is determined based on the body surface area in clinical treatment. Ishibashi et al. reported a formula for predicting NDP clearance based on renal function like Calvert's formula for CBDCA. We conducted the present study to evaluate the Ishibashi's formula. Methods: A total of 22 patients with cervical or ovarian cancer, who underwent chemotherapy consisting of NDP and irinotecan (CPT-11), were examined in this study. Blood samples were collected at 0, 1, 2, 4, and 6 h after the end of infusion of NDP (48-80 mg/m ² ), and free platinum concentrations were measured. Observed AUCs were compared with predicted AUCs, which were calculated by the Ishibashi's formula. In addition, the relative reduction in platelets (PLTs) was assessed as a parameter of adverse effects. Results: The observed AUC of NDP ranged from 4 to 14 (μg h ^-1 ml ^-1 ) with large variation. The predicted AUC based on renal function was correlated with the observed AUC. There was a relationship between observed AUC and the decrease in PLTs. Conclusions: Ishibashi's formula would be predictable and useful for estimating the individual dose of NDP.