[Distribution of 1-hexycarbamoyl-5-fluorouracil in rats and human patients, and clinical results in patients with colorectal cancer].

The distribution of 1-hexylcarbamoyl-5-fluorouracil (HCFU), one of the "masked-type" derivatives of 5-fluorouracil (5-FU), was studied following oral administration in rats and human patients with colorectal cancer. In rats, the highest level of 5-FU from HCFU was shown in the stomach and kidney, followed by the large intestine. After oral administration of HCFU for seven days, the level of 5-FU in tumors from patients was higher than that in tumors from patients given single administration. The clinical response of HCFU administered orally was then evaluated in patients with colorectal cancer. Out of 25 evaluable patients the overall response rate including a CR and six PRs was 28.0%. Overall survival rates for patients were 75.0% in one year, 32.0% in two years, and 13.6% in three years. From these results, it was suggested that HCFU is a useful anticancer agent for colorectal cancer.