This is a phase III randomized clinical trial of SU101, an inhibitor of platelet-derived growth factor signaling, versus oral procarbazine for recurrent glioblastoma multiforme of the brain. The study is sponsored by the Sugen Corporation. SU101 has shown activity in Phase I and I/II trials, and the maximum tolerated dose and major toxicities have been determined. Oral procarbazine is a standard chemotherapy treatment for recurrent glioblastoma. The primary is survival. Sugen plans to enroll 380 patients nationally. We project enrollment of 24 patients over 2 years at UMMC. Patients randomized to SU101 will receive 6-hour infusions in the GCRC outpatient setting on 10 occasions during the first 8-week cycle and 7 occasions during subsequent cycles. These patients will also need blood drawn in the GCRC 4 times during each cycle and sent to a reference lab. Patients randomized to procarbazine will need only the blood draws.