The pharmacokinetics of vindesine were investigated during treatment of 15 patients with progressive malignancies refractory to conventional treatment. Patients were administered one of three IV dose schedules: 3.0 mg/m2 bolus injection, 1.2 mg/m2/day infusion for 5 days, or 2.0 mg/m2/day infusion for 2 days. Concentrations of the drug in the serum and urine were determined by radioimmunoassay. Serum concentrations were highest (5 X 10(-7) M) in patients receiving a bolus injection, but fell to nondetectable levels by 48 h in four of five patients (terminal t1/2 15.0 +/- 9.4 h). Compared with bolus injection, 1.2- to 1.4-fold greater areas under the blood concentration curve were observed during infusions of 2.0 mg/m2 and 1.2 mg/m2. Whereas steady-state concentrations (approximately 1 X 10(-8) M) were maintained throughout the infusion of 1.2 mg/m2/day progressively increasing serum levels were observed during the infusion of 2.0 mg/m2/day. Serum concentrations fell rapidly following discontinuation of the 2.0-mg/m2 infusion, but were somewhat more sustained in the 1.2-mg/m2 infusion group. The average urinary excretion was similar for each dose-schedule (8%-11% of the total dose). The pharmacokinetics of vindesine are influenced by variations in dose schedule.