Double-modulation of 5-Fluorouracil by methotrexate and leucovorin in advanced colorectal-carcinoma

A phase II trial was performed to evaluate the efficacy and toxicity of a double modulation of 5-fluorouracil (5-FU) by methotrexate (MTX) and leucovorin (LV) as first line chemotherapy in advanced colorectal carcinoma. Between January 1990, and April 1992, 42 patients with metastatic or advanced recurrent (inoperable) colorectal cancer were entered into the study. Therapy consisted of a sequential combination of MTX, LV and 5-FU. MTX was administered at a dose of 150 mg/m2 over 20 minutes I.V. infusion at hour (h) 0, followed 19 h later by LV 50 mg/m2 over 2 h infusion. 5-FU 900 mg/m2 was given by I.V. push injection at h 20. Starting 24 h after MTX administration all patients received LV 15 mg/m2 intramuscularly every 6 h for six doses. Treatment was repeated every 15 days until progressive disease, severe toxicity, or death. Four patients were considered not evaluable for response. Objective regression (OR) was observed in 14 of 38 patients (37%, 95% confidence interval 23-53%). Two patients (5%) obtained complete response (CR) and 12 (32%) partial response (PR). Median time to treatment failure was 6 months (range 1-21). Median survival for the whole group of patients was 13 months (range 1-27). Toxicity was within acceptable limits but one therapy-related death due to severe leukopenia and sepsis was observed. Double modulation of 5-FU with MTX and low dose of LV is an active regimen against advanced colorectal carcinoma and represents a promising strategy that should be further explored.