Phase II evaluation of metoprine with leucovorin rescue in patients with advanced colorectal carcinoma.

In a phase II trial 24 patients with measurable metastatic colorectal carcinoma were treated every 2 weeks with high-dose metoprine at 175 mg/m2 and leucovorin rescue. Hematologic toxicity was mild; the limiting toxicity was CNS, occurring in 54% of the patients. No responses were observed, but four patients had disease stabilization. High-dose metoprine with leucovorin rescue appears ineffective in previously treated patients with colorectal carcinoma in the dose and schedule used in this study.