Phase I study of combination chemotherapy with 5-fluorouracil (5-FU) and nedaplatin (NDP): adverse effects and eecommended dose of NDP administered after 5-FU.

When nedaplatin (NDP) was used as a single agent in the phase I study, the dose-limiting toxicity (DLT) was thrombocytopenia and the recommended dose (RD) was 100 mg/m2. However, the DLT, maximum tolerated dose (MTD) and RD of NDP used in combination with 5-fluorouracil remained unknown. Therefore, we performed this study to assess the DLT and RD of NDP administered after 5-fluorouracil (5-FU). In this study, 5-FU was administered to 38 patients at a fixed dose (700 mg/m2/d on days 1-5) and NDP administered on day 6 at an initial dose of 80 mg/m2, which was subsequently increased to 100, 120, 130, 140, 150, and 160 mg/m2. The DLT of NDP was leukopenia and its MTD and RD were 160 and 150 mg/m2, respectively. Concerning impairment of renal function, only two patients had a grade I increase in serum creatinine. There were 19 responders (50%, 19/38) achieving partial response or complete response in the evaluation of antitumor effect. The result of this study is notable in that administration of 5-FU before NDP allows the dose of NDP to be substantially increased.