Phase II study of trimetrexate, fluorouracil, and leucovorin for advanced colorectal cancer

A phase II study to evaluate the response rate and toxicities of a trimetrexate, fluorouracil (5FU), and leucovorin regimen in patients with advanced incurable colorectal cancer.

Thirty-six patients with unresectable or metastatic colorectal cancer who had not been treated for advanced disease received the following chemotherapy regimen weekly for six courses every 8 weeks: trimetrexate 110 mg/m2 intravenously (I.V.) on day 1, leucovorin 200 mg/m2 I.V. on day 2 (24 hours later), 5FU 500 mg/m2 on day 2 immediately following leucovorin, and oral leucovorin 15 mg every 6 hours for seven doses starting 6 hours after 5FU. Patients were treated until progression or unacceptable toxicity.

Thirty patients were assessable for response, and all 36 were assessable for toxicity. Two patients (7%) achieved a complete response (CR) and 13 (43%) a partial response (PR), for an overall response (OR) rate of 50% (95% confidence interval [CI], 32% to 68%). Analysis by intent to treat demonstrated a 42% OR rate (95% CI, 26% to 58%). At final analysis, 16 patients were alive. The median survival duration for the entire cohort was 53.4 weeks. Gastrointestinal toxicity was most common, with 21 patients (58%) having grade 3/4 diarrhea and 12 patients (34%) grade 3/4 nausea. Hematologic toxicity was generally low grade, although two patients died of sepsis.

The combination of trimetrexate with 5FU and leucovorin is active in metastatic colorectal cancer. Gastrointestinal toxicity with this regimen is most prominent, but is manageable.