A phase I and pharmacokinetic study of docetaxel administered in combination with continuous intravenous infusion of 5-fluorouracil in patients with advanced solid tumors.

Encouraged by preclinical synergism between docetaxel and 5-fluorouracil (5FU), we conducted a Phase I study of docetaxel in combination with continuous i.v. infusion of 5FU in patients with advanced solid tumors to determine the maximum tolerated dose, the recommended dose for Phase II studies, and the safety and pharmacokinetic profiles of this combination. Forty-two patients with advanced solid tumors, most of whom had been previously treated, received docetaxel on day 1 as a 1-h i.v. infusion, immediately followed by a 5-day continuous i.v. infusion of 5FU, every 3 weeks without hematopoietic growth factor support. All patients were premedicated with methylprednisolone. Dose levels of docetaxel/SFU studied were (daily dose, in mg/m2) 60/300, 75/300, 75/500, 75/750, 85/750, 85/1000, and 75/1000. Forty-one patients were assessable for toxicity. The maximum tolerated dose determined during the first cycle was 1000 mg/m2/day for 5 days of 5FU with either 75 or 85 mg/m2 docetaxel. Dose-limiting toxicities at these dose levels were reversible secretory diarrhea (4 of 12 evaluable patients), stomatitis (2 patients), and febrile neutropenia (2 patients). Overall, grade 3/4 neutropenia and febrile neutropenia were seen in 63.4% and 9.8% of the patients, respectively. Four patients experienced grade 3/4 infection, which led to toxic death in one of them. There were five early deaths: (a) one was clearly treatment related; (b) two others were possibly treatment related or remotely treatment related; and (c) two deaths were not related to the study drugs. Partial responses were documented in 5 of 39 evaluable patients. Pharmacokinetic results of both drugs were consistent with those from single-agent studies. The recommended dose of this combination, which showed acceptable toxicity and antitumoral activity at various dose levels, is 85 mg/m2 docetaxel given as a 1-h i.v. infusion on day 1 immediately followed by a 5-day continuous i.v. infusion of 5FU (750 mg/m2/day). This study has been extended by adding cisplatin on day 1 of the combination of docetaxel and 5FU.