Phase II study of first-line LY231514 (multi-targeted antifolate) in patients with locally advanced or metastatic colorectal cancer: An NCIC Clinical Trials Group study

Background: Metastatic colon cancer is difficult to treat with treatment being palliative and with little effect on survival. This trial has evaluated the effects of LY231514 (Multitargeted antifolate (MTA)) given to previously untreated patients with recurrent or metastatic colorectal carcinoma. Patients and methods: All patients were required to have a histological diagnosis of colorectal adenocarcinoma with measurable disease and no prior chemotherapy for metastatic disease. Patients had to have had performance status of 0-2, pretreatment absolute granulocyte count of greater than or equal to 1.5 x 10(9)/l and a platelet count of greater than or equal to 150 x 10(9)l. Patients received MTA at a dose of 600 mg/m(2) by 10 minute infusion on day 1 repeated every 21 days. After the first 9 patients, this dose was reduced down to 500 mg/m(2) every 21 days because of toxicity. Doses of MTA were modified depending on nadir counts. Results: Thirty-two eligible patients were enrolled and twenty-nine were evaluable for response. Three patients did not have repeat radiological testing to determine response because they went off study after only one cycle of treatment due to toxicity. In the 29 evaluable patients, there was 1 complete response, 4 partial responses and 14 patients with stable disease. Response rate was 17.2% (95% confidence intervals: 5.8%-35.8%). All responses occurred in the patients receiving a starting dose of MTA 500 mg/m(2). Median time to progression for all eligible patients was 3.3 months. The most common toxicities experienced were mild to moderate fever, lethargy, anorexia, nausea, vomiting, stomatitis, abdominal pain, diarrhea, and skin rash. There was one death due to sepsis. Conclusion: Single-agent MTA at 500 mg/m(2) given every three weeks has modest activity in metastatic colorectal carcinoma.