A phase I/II study of alternating constant rate infusion floxuridine with constant rate infusion vinblastine for the treatment of metastatic renal cell carcinoma.

BACKGROUND

Metastatic renal cell carcinoma (RCC) is largely chemoresistant. The efficacy of cell cycle specific chemotherapeutic agents, particularly those with short half-lives, may be enhanced by the use of constant rate infusion schedules. Infusional floxuridine has been demonstrated to have a response rate of approximately 20%. Infusional vinblastine has not been tested extensively in patients with metastatic RCC. The sequential use of these agents was designed to increase efficacy and limit toxicity.

METHODS

Fifteen patients with metastatic RCC were treated with constant rate infusion floxuridine, 0.075 mg/kg/day for 14 days, followed by a constant rate infusion of vinblastine, 0.7 mg/m2/day for 14 days. The cycle repeated every 28 days and floxuridine and vinblastine doses were incrementally increased until the maximum tolerated dose (MTD) for each patient was reached.

RESULTS

Four patients had partial responses (27%), which were maintained for 3, 9, 16 and 19+ months, whereas five patients had stable disease for 3-15 months. Median survival from initiation of therapy was 379 days. Three of four responses occurred in nonpulmonary locations, and all responses occurred in patients who had a prior nephrectomy. MTD for floxuridine was 0.1 mg/kg/day and for vinblastine, 0.7 mg/m2/day. Toxic reaction to floxuridine was limited to diarrhea, whereas the principle dose-limiting toxic reaction for vinblastine was neutropenia. Catheter-related complications were also observed.

CONCLUSIONS

Alternating constant rate infusion floxuridine and constant rate infusion vinblastine is active in the treatment of metastatic RCC. Whether this regimen is superior to infusional floxuridine is undetermined. Although the toxicity associated with this regimen is manageable, it appears to be more severe than that reported with infusional floxuridine alone.