Phase I Evaluation of Continuous 5-Fluorouracil Infusion Followed by Weekly Paclitaxel in Patients with Advanced or Recurrent Gastric Cancer

Abstract

We conducted a phase I trial of escalating doses of weekly paclitaxel (Taxol) in combination with a fixed systemic administration of 5-fluorouracil (5-FU) in patients with advanced or metastatic gastric cancer. Patients with advanced or recurrent gastric cancer were treated with escalating doses of weekly paclitaxel as a 60 min intravenous (i.v.) infusion, along with a fixed dose of continuous 5-FU infused over 5 days. Plasma sampling was performed to characterize the pharmacokinetics and pharmacodynamics of paclitaxel. Eighteen patients received combination therapy at four dose levels of weekly Taxol, ranging from 60 to 90 mg/m2/week. Dose-limiting toxicities > grade 3 were observed at the 90 mg/m2/week dose level. Toxicities included anemia, neutropenia, thrombocytopenia, nausea and alopecia. Two episodes of grade 4 neutropenia occurred in two of the three patients receiving this dose. At each dose level, pharmacological studies documented the persistence of significant serum paclitaxel levels over 24 h after drug administration. The maximum tolerated dose (MTD) for this regimen was 90 mg/m2/week of paclitaxel for 3 weeks plus 600 mg/m2/day of continuous 5-FU for 5 days. The combination of weekly paclitaxel and 5-FU demonstrated an acceptable toxicity profile and feasible pharmacokinetic results suggesting its practical applicability. Based on these findings, the recommended dose and schedule for phase II study of combination chemotherapy is paclitaxel 80 mg/m2/week x 3 over 4 weeks, and continuous 5-FU 600 mg/m2/day x 5 days every 4 weeks.