The primary endpoint for Cohort 2 is the proportion of participants progression free at 6 months (PFS6). Historical comparison data suggest that ineffective therapies in recurrent GBM have a PFS6 rate of approximately 9-16% (Wong 1999; Lamborn 2008). This trial was sized to differentiate between a 15% versus a 32% PFS6. With a total sample size of 50 participants, this design yields at least 90% power with a one sided alpha < 0.1 to detect a true PFS6 rate of at least 32%. If the number of successes was ≥ 12, the therapy would be considered worthy of further study.