Dual modulation of 5-fluorouracil with folinic acid and hydroxyurea in metastatic colorectal cancer.

Leucovorin and 5-fluorouracil (5-FU) can be further modulated with hydroxyurea. Sixty-eight patients with advanced colorectal cancer received every 2 weeks hydroxyurea per os 1.5 g to 2 g days -1, 1, and 2; leucovorin 200 mg/m2 iv over 2 hours started at least 1 hour after hydroxyurea and per os 100 mg/m2 12 hours later, on days 1 and 2; 5-FU, bolus 400 mg/m2 during leucovorin infusion and 24 hours continuous infusion 600 mg/m2, repeated on days 1 and 2. Two complete responses (7%), 8 partial responses (30%), 12 no change (44%), and 5 progressions (19%) were observed among 31 nonpreviously treated patients. Four partial response (11%), 15 no change (43%), and 16 progressions (46%) were observed among 37 pretreated patients. Nineteen were treated after progression on the same regimen without oral leucovorin and hydroxyurea, 1 achieved PR and 10 showed no change. Among them, 6 experienced response or stabilization of longer duration than with previous treatment. Twelve-month survival was 61% in non-pretreated and 43% in pretreated patients as of the start of chemotherapy. Toxicity was mild with nausea in 46%, diarrhea in 37%, and mucositis in 36%. The first-line response rate is in the range of leucovorin and 5-FU alone. Some pretreated patients benefited from this regimen.