- Patients who have had chemotherapy or radiotherapy within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study, or those who have not recovered from AEs due to agents administered more than 4 weeks earlier. Patients must be greater than or equal to 2 weeks since any investigational agent was administered as part of an exploratory IND study and should have recovered to eligibility levels from any toxicity.