Aziridinylbenzoquinone (AZQ), a quinone-containing lipophilic alkylating agent with molecular properties allowing for good penetration through the blood-brain barrier into the central nervous system, was evaluated in a phase II trial for recurrent gliomas patients. Twenty-four patients with computed tomography (CT) scan measurable disease were entered into the trial and received AZQ in doses of a weekly infusion of 15 mg/m2 (group A) and 17.5 mg/m2 (group B). Twenty-two patients were evaluable for both response and toxicity. There were no complete responses in this study. Partial response rates of 23% (3/13) and 11% (1/9) were achieved in group A and group B patients, for a median duration of response of 35 (range 10-106 weeks) and 19 weeks, respectively. The disease was stabilized in five patients from group A and in four patients from group B. Toxicity was mainly hematologic.