Clinical Evaluation of Ftorafur (Pyrimidine-deoxyribose N₁2'-Furanidyl-5-fluorouracil)

Ftorafur, a possible sustained-release formulation of 5-fluorouracil, was administered to 27 patients with metastatic cancers. The majority of patients had adenocarcinoma, most of which (60%) arose from the gastrointestinal tract. Ftorafur was given i.v. at doses ranging from 1 to 3 g/ sq m/day for 5 days, repeated every 2 to 3 weeks. Gastrointestinal (68%) and neurological (17%) toxicities were the most common side effects encountered in this study and became dose limiting at doses greater than 2 g/sq m/day for 5 days. Myelosuppression (7%) was infrequent. Other toxicities included weakness (20%), chills and fever (8%), and phlebitis (1%). Of 24 evaluable patients, 4 (17%) responded (1 complete and 3 partial remissions). Responses were seen in 1 of 8 carcinomas of the lung, 1 of 5 carcinomas of the stomach, 1 of 3 carcinomas of the colon, and 1 of 1 carcinoma of the jejunum. The duration of response ranged from 4 to 58 weeks. The results of this study resemble somewhat those obtained with the laborious 5-day continuous i.v. infusion of 5-fluorouracil. Daily doses of 2 g/sq m for 5 days, repeated every 3 weeks, produced significant antitumor effect and tolerable toxicity.