A randomized trial of two schedules of trimetrexate versus 5-fluorouracil in advanced colorectal cancer: a Southwest Oncology Group study.

Trimetrexate (TMQ), a non-classical folate antagonist, was studied in a randomized controlled trial in patients with advanced colorectal cancer and without prior chemotherapy. Patients were randomly assigned to one of three treatments: TMQ at 200 mg/m2 i.v. q 2 weeks, TMQ at 12 mg/m2 i.v. daily x 5 or 5-fluorouracil (5-FU) at 15 mg/kg i.v. weekly. Overall response rates were: 6% (four partial responses in 71 patients, 95% CI of 2-14%) for q 2 week TMQ, 0% (zero of 29, 95% CI of 0-29%) for daily x 5 TMQ and 18% (two complete and nine partial responses in 62 patients, 95% CI of 9-30%) for 5-FU. Median survival estimates were 10.3 months for the q 2 week TMQ schedule, 8.7 months for the daily x 5 TMQ schedule and 13.6 months for the 5-FU schedule. Grade < or = 3 toxicities were significantly more common with TMQ. TMQ does not appear to have significant antitumor activity against colorectal cancer.