- Patients must have recovered from toxicity of prior therapy; an interval of at least 3 months must have elapsed since the completion of the most recent course of radiation therapy, while at least 3 weeks must have elapsed since the completion of a non-nitrosourea containing chemotherapy regimen, and at least 6 weeks since the completion of a nitrosourea containing chemotherapy regimen; NOTE: For non-cytotoxic, FDA approved agents (i.e. celebrex, thalidomide, etc.) therapy could be started 2 weeks after discontinuing this agent provided the patient has fully recovered from all toxicity associated with the agent; for investigational, non-cytotoxic agents a minimum of 3 weeks must have elapsed before the patient will be eligible for this study