Tumor response rate of stratum B1 participants was evaluated after 1 treatment course of temozolomide plus peginterferon alpha-2b. Complete response (CR) and partial response (PR) confirmed with repeated scan at least 4 weeks apart following completion of course 1 therapy. CR defined as disappearance of all target and non-target lesions with no new lesions detected. If available, no disease must be detected by immunocytology or serum tumor markers. PR defined as at least 30% decrease in disease measurement compared to disease measurement at study entry with no new lesions detected. Progressive disease (PD) defined as at least 20% increase in the disease measurement compared to the smallest disease measurement recorded since start of treatment, or appearance of one or more new lesions. Stable disease defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD compared to smallest disease measurement since start of treatment.