Phase I-II trial of a 5-day continuous infusion of vinblastine sulfate.

Vinblastine sulfate was administered to 28 patients as a continuous infusion for five consecutive days in doses of 0.75 to 2.0 mg/m2. Pharmacokinetic studies in 4 patients showed that plasma levels increased rapidly after beginning the infusion with a steady state occurring in 10-48 hours at 2 ng/ml for 1.25 mg/m2, and 5-8 ng/ml for 2.0 mg/m2. The T 1/2 b after completion of the infusion was 19 hours. Dose-limiting toxicity was myelosuppression. A partial remission of four months duration was observed in a patient with adenocarcinoma of the gastroesophageal junction. One patient, who had been heavily pretreated, obtained partial remission while three patients with breast cancer had a minor response. There was no response in 10 patients with hypernephroma. The suggested starting dose is 2 mg/m2 for un-pretreated cases and 1.75 mg/m2 daily for 5 consecutive days monthly for prior treated cases.