Phase II study of divided-dose vinblastine in advanced cancer patients.

A better therapeutic index has been obtained in breast cancer patients when vinblastine is given by a 5-day continuous infusion program than by i.v. bolus; the continuous infusion pharmacokinetics has been reproduced by an iv divided bolus at 0 and 48 h, which may be more easily applied to outpatients. We performed a broad phase II study in 97 advanced cancer patients in which vinblastine was administered by i.v. divided bolus at 0 and 48 h at the starting dose of 3.5-4 mg/m2, every 3 weeks. Our aim was to confirm the results achieved by continuous infusion and to investigate the toxicity pattern of this novel administration schedule. Neurotoxicity and myelosuppression were the main side effects: constipation and peripheral neurotoxicity respectively developed in 28% and 38% of patients and were severe in 5% and 1%. Leukopenia and thrombocytopenia respectively occurred in 70% and 40% of patients and were severe in 11% and 4%. Four partial responses, 38 no changes and 42 progression were obtained out of 84 evaluable patients. Responses were seen in tumors of breast, lung, and head and neck. Our results do not support the use of vinblastine in divided doses in advanced cancer patients.