A phase I clinical and pharmacokinetic study of Brequinar sodium, DUP 785 (NSC 368390), using a weekly and a biweekly schedule

Abstract

Brequinar, DUP 785, is a substituted 4-quinoline carboxylic acid derivative which in preclinical studies has shown broad antitumor activity. It is a novel antimetabolite blocking pyrimidine nucleotide synthesis. In a clinical phase I study, 83 patients were treated on a weekly schedule and 18 patients on a biweekly schedule. The drug was given intravenously as a short infusion. Three patients were entered on each dose level from a starting dose of 6 mg/m2 up to 2600 mg/m2 weekly. The dose ranges on a biweekly schedule were 500-850 mg/m2. There was no dose escalation in individual patients. Pharmacokinetic studies were performed in 19 patients on a weekly schedule and in two patients on a biweekly schedule. A biphasic decay in plasma was observed with a median half life of 10 h (5.1-23.4). The main dose-limiting toxicity was thrombocytopenia. Of non-hematologic side-effects, stomatitis/mucositis occurred frequently. Skin eruptions occurred rarely, but were a major problem when found. All side-effects were fully reversible; there were no signs of cumulative toxicity. Antitumor activity was observed in one patient with a lung metastasis from a bladder cancer and in a patient with an unknown primary tumor. The recommended doses for phase II trials with DUP 785 are: 1500-2000 mg/m2 on a weekly schedule and 500-750 mg/m2 on a biweekly schedule dependent on status before treatment.