OUTLINE: Patients receive O6-benzylguanine IV over 1 hour followed 1 hour later by carmustine IV over 15 minutes. Treatment continues every 6 weeks for a minimum of 2 courses in the absence of unacceptable toxicity or disease progression. Patients with progressive disease are followed every 6 months until death. Patients without progressive disease are followed every 3 months for 1 year.