Oxaliplatin with high-dose leucovorin and 5-fluorouracil 48-hour continuous infusion in pretreated metastatic colorectal cancer.

Oxaliplatin has shown in vivo cytotoxic activity against colorectal cell lines. Preliminary studies suggest potentiation of fluorouracil (5-FU). To assess this issue, we performed a phase II study in pretreated patients with advanced colorectal cancer (CRC) resistant to leucovorin and 5-FU. The regimen (FOLFOX2) consisted of oxaliplatin 100 mg/m2 as a 2-h infusion on day 1; leucovorin 500 mg/m2 as a 2-h infusion, followed by 5-FU 24-h infusion 1.5-2 g/m2 for two consecutive days every 2 weeks. The initial 5-FU dose was 1.5 g/m2 for two cycles and increased to 2 g/m2 in case of no toxicity > grade 2. 46 patients were treated, all with disease progression on leucovorin and 5-FU therapy for metastatic disease, or relapse less than 6 months after the end of adjuvant therapy. One complete response (CR) and 20 partial responses (PRs) were observed for an overall response rate of 46%. 22 patients had prior documented progression while receiving the same schedule of leucovorin and 5-FU as the one used in the FOLFOX2 regimen, and among them, 10 had PRs (45%). From the start of FOLFOX2, median progression-free survival was 7 months and median survival 17 months. WHO toxicity > or = grade 3 per patient was: peripheral neuropathy 9%, nausea 4%, diarrhoea 9%, mucositis 13%, neutropenia 39%, thrombocytopenia 11%, alopecia 9%, and allergy 2%. Overall, 21 patients (46%) experienced grade 3-4 toxicity. This combination of leucovorin, 5-FU and oxaliplatin achieves a high response rate in pretreated patients with CRC resistant to leucovorin and 5-FU. Limiting toxicities are neutropenia and peripheral neuropathy.