- Chemotherapy or palliative radiotherapy for recurrent and/or metastatic disease within 3 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study or failure to recover to at least grade 1 from adverse events due to agents administered more than 4 weeks earlier; concomitant chemoradiation therapy within 6 weeks prior to entering the study or failure to recover to at least grade 1 from adverse events due to agents administered more than 4 weeks earlier