- Completed prior chemotherapy a minimum of 4 weeks previously (6 weeks for BCNU and/or mitomycin C), 4 weeks for prior biologic therapy, and 2 weeks for localized radiation therapy. No prior PS-341 is allowed. All treatment related toxicity must have resolved as well. Patients can not receive concomitant radiation therapy. Prior TMZ or DTIC is only allowed in those patients enrolled into the prior chemotherapy cohort