Phase I chemotherapy study of biochemical modulation of folinic acid and fluorouracil by gemcitabine in patients with solid tumor malignancies.

PURPOSE: This phase I biochemical modulation study evaluated the maximum-tolerated dose (MTD), toxicity, and effectiveness of the combination of folinic acid (FA)/fluorouracil (5-FU) followed by escalated dose levels of gemcitabine (FFG) in patients with advanced solid tumors. PATIENTS AND METHODS: Patients were refractory to primary treatment and/or without effective treatment options. Twenty-eight patients received an intravenous (IV) infusion of FA 100 mg/m(2) over 1 hour and a 5-FU 450 mg/m(2) IV bolus in the middle of the FA infusion. After the FA infusion, gemcitabine was administered at a steady rate of infusion of 10 mg/m(2)/min over initially 30 minutes and with increases of an additional 15 minutes at each given level. One cycle consisted of six weekly treatments followed by a 2-week rest. RESULTS: The MTD of gemcitabine was established at 900 mg/m(2) given over 90 minutes. Eight patients of 21 with metastatic colorectal cancer achieved responses (one complete response; seven partial responses), for a response rate of 38%. Responses were seen across the gemcitabine doses of 300 to 900 mg/m(2). One patient had prior treatment with FA/5-FU for advanced disease. Patients with colorectal carcinoma had a median survival of 18 months, and the patient with lung carcinoma has been alive for 24+ months. CONCLUSION: The combination chemotherapy of FFG was well tolerated and may benefit patients with advanced colorectal carcinoma. A phase II evaluation in this patient population is in progress.