Multimodal biochemical modulation of 5-fluorouracil activity in advanced colorectal cancer with allopurinol, folinic acid and dipyridamol.

It is now commonly accepted that the activity of 5-fluorouracil (5FU) may be potentiated by folinic acid (FA). Moreover dipyridamol (DIP) interacts with the pyrimidine salvage pathway of 5FU. In 28 patients with advanced colorectal cancer, in progression under FA-5FU, we continued treatment with FA-5FU plus DIP. FA 200 mg/m2/day. i.v. push was given before 5FU 766.52 mg/m2/day (mean dose), in 60 min infusion for 5 subsequent days. Cycle was repeated every 21 days. We noticed greater but not seriously increased toxicity by the addition of DIP. The addition of DIP did not change response rates; it seemed to increase response but not significantly.