 - Prior chemotherapy, biological therapy, radiation therapy, androgens, thalidomide, immunotherapy, other anticancer agents within 21 days of starting study treatment not including palliative radiotherapy at focal sites. Prior use of an investigational monoclonal antibody therapy within 3 months, or prior use of nitrosoureas or mitomycin C within 6 weeks. Patients must have recovered from acute toxicity due to radiotherapy. 