Purpose: To determine the maximum tolerated dose of oxaliplatin (L-OHP) given as a two-hour infusion followed by raltitrexed (Tomudex [TOM]) administered as a 15-min infusion on day 1, and bolus 5-fluorouracil (5-FU) modulated by a fixed dose of levo-folinic acid (LFA) 250 mg/m2 on day 2, recycling every two weeks, and to have preliminary evidence of activity of this combination in pretreated advanced colorectal cancer patients.
Patients and methods: Fifty-two patients with advanced colorectal carcinoma previously treated with one (25 cases) or two or more lines of chemotherapy, including irinotecan (26 cases), and/or modulated 5-FU (40 cases) entered this study. Starting doses of L-OHP, TOM, and 5-FU were 85, 2.5 and 750 mg/m2, respectively.
Results: Seven dose levels were tested. Neutropenia was the main dose limiting toxicity of the dose escalation (8 of 13 cases). The recommended doses were 130 mg/m2 of L-OHP, and 3.0 mg/m2 of TOM on day 1, followed by 250 mg/m2 of LFA, and 1050 mg/m2 of 5-FU on day 2, every two weeks. Severe diarrhoea and stomatitis were rarely reported. Most patients complained of mild peripheral sensitive aeurotoxicity, which was related to the cumulative dose of L-OHP. Twelve patients were considered as having a major responses (one complete), and an additional eight patients showed a minor response; the median time to treatment failure was twenty-four weeks.
Conclusions: With this regimen it is possible to give full doses of all three cytotoxic drugs every two weeks. Its activity and its manageable toxicity profile deserve further evaluation in pretreated advanced colorectal cancer patients.