6. Patients must have been off previous chemotherapy or radiotherapy for the three weeks prior to entering this study. Six weeks will be required if the patient has received therapy which is known to have delayed toxicity (mitomycin or a nitrosurea). Five half-lives will be required for biologic/targeted therapies with short (<24 hour) half-lives and pharmacodynamic effects. Patients may have received palliative radiation immediately before (or during) treatment provided radiation is not to the only target lesion available.