Chronomodulated 5-day infusion of floxuridine and L-folinic acid in patients with advanced malignancies: a feasibility and tolerability study.

The best schedule for administering floxuridine (FUDR) has not yet been established. Duration of infusion, need (and dosage) of leucovorin (folinic acid, FA), and circadian timing need to be further specified. Nevertheless, FUDR delivery according to circadian rhythms has allowed increase of dose intensity without enhancing the side effects. A 5-day infusional schedule combining FUDR and L-FA was devised as an attempt to increase dose intensity and to provide therapy every 3 weeks to patients with advanced cancer. An ambulatory programmable-in-time pump was used for this purpose. Fourteen patients entered this trial. Two dose levels (mg/kg x 5 days) were evaluated: 0.5 mg/kg/day in six patients and 0.525 mg/kg/day in eight patients. Both patient groups received a concurrent infusion of L-FA 10 mg/m2/day i.v. The delivery patterns of both FUDR and L-FA varied sinusoidally during the 24 hours with a maximum at 18.00 hours. Courses were repeated every 3 weeks. Of 35 courses, treatment produced mucosites greater than grade 2 in only two of them. No severe diarrhea, the dose-limiting toxicity of FUDR when infused over 14 days, was encountered at the dose levels tested. This 5-day chronotherapy schedule allowed delivery of a larger amount of FUDR than the flat delivery described in a previous report. A daily dose of 0.525 mg/kg FUDR, combined with 10 mg/mg2 L-FA, with intraindividual dose escalation according to tolerance, is recommended for future investigations of the activity of this chronotherapy schedule.