Phase II study of oxaliplatin in Japanese patients with metastatic colorectal cancer refractory to fluoropyrimidines

Background: Although oxaliplatin (L-OHP) combined with infusional 5-fluorouracil (5-FU) and leucovorin (LV) is one of the standard chemotherapy regimens for metastatic or recurrent colorectal cancer, its introduction to Japan has been delayed. Phase I studies of L-OHP monotherapy in Japan showed no dose-limiting toxicity at the internationally recommended dose of 130 mg/m² every 3 weeks, as well as no racial differences in pharmacokinetics as compared with Western subjects. This study aimed to clarify the efficacy and safety of L-OHP monotherapy in patients with metastatic colorectal cancer refractory to fluoropyrimidines. Methods: Patients with metastatic colorectal cancer who had failed to respond to fluoropyrimidine-based chemotherapy received L-OHP at a dose of 130 mg/m² every 3 weeks. Results: Sixty patients were enrolled. Two ineligible patients and one untreated patient were excluded from analysis. The median number of treatment cycles was 4 (range, 1 - 6). The overall response rate was 9% (5/57, 95% CI: 4 - 19%). The median time to progression was 2.7 months, and the median survival time was 11.1 months. Grade 3 major toxicity comprised thrombocytopenia (12%) and nausea (11%). There was no grade 4 toxicity. All patients experienced mild to moderate sensory neurotoxicity without functional impairment interfering with activities of daily living. Conclusions: The efficacy and toxicity of L-OHP in Japanese patients with metastatic colorectal cancer refractory to fluoropyrimidines is apparently similar to those in Western patients.