Procarbazine chemotherapy in the treatment of recurrent malignant astrocytomas after radiation and nitrosourea failure. The Brain Tumor Study Group has shown procarbazine (PCB) to be as effective an adjuvant treatment as 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). We treated 35 patients with recurrent malignant astrocytomas after radiation and nitrosourea failure with successive courses of PCB 150 mg/m2/d for 28 days every 8 weeks. After 2 courses, 2 patients had complete responses, 7 had partial responses, 11 had stable disease, and 15 had progression. Significantly more patients receiving PCB had complete or partial responses or stable disease than a similar group of patients in a previous trial who received intra-arterial (IA) cisplatin (DDP). There is a significant advantage in time to disease progression for those receiving PCB compared with those receiving IA diaziquone (AZQ). Our results suggest that PCB is a more effective 2nd agent than IA DDP or AZQ following radiation and nitrosourea failure. 