- Chemotherapy: A minimum of 3 weeks (4 weeks for carboplatin or investigational anticancer agents and 6 weeks for nitrosoureas and mitomycin C) must have elapsed between the end of treatment and registration into this study. Prior tyrosine kinase inhibitor therapy is permitted. Patients must have recovered from any treatment-related toxicities (except for alopecia, fatigue, and grade 1 neurotoxicity) prior to registration