Background: It has been suggested that there is a relationship between 5-fluorouracil (5-FU) dose levels and response rates. A bimonthly 2-day regimen of leucovorin (LV) and 5-FU bolus plus infusion has been found to be superior to a monthly 5-FU bolus with low dose LV. Based on these reports, a first-line Phase II study was performed in 101 patients with advanced colorectal carcinoma who were given a bimonthly combination of high dose LV and a high dose 48-hour infusion of 5-FU.
Methods: The selected regimen included a 2-hour infusion of LV, 500 mg/m2, on each of 2 consecutive days and a 48-hour infusion of 5-FU, 1.5 to 2 g/m2/24 hours starting after Day 1 of LV treatment every 2 weeks until there was evidence of disease progression. Evaluation was performed every six cycles. This study reports the treatment of 101 patients with measurable disease.
Results: World Health Organization toxicity Grade 3-4 occurred in 15% of patients, nausea in 2%, diarrhea in 5.1%, mucositis in 4%, neutropenia in 4% (Grade 4: 2%), hand-foot syndrome in 2%, alopecia in 4%, and encephalopathy in 1%. The overall response rate was 33.7%. Five patients had a complete response (5%), and 29 had a partial response (28.7%). In 45 patients disease was stable (44.6%), and in 19 patients there was disease progression (18.8%). Three patients (3%) could not be evaluated. The median progression free survival was 8 months and median survival was 18 months.
Conclusions: In the current study, bimonthly high dose LV and a high dose 48-hour infusion of 5-FU had activity in patients with advanced colorectal carcinoma. Toxicity is notably low, and the regimen is suitable for use in combination with other drugs.