The primary purpose of the study is to determine the efficacy of an investigational therapy called DCVax(R)-L in patients with newly diagnosed GBM for whom surgery is indicated. Patients must enter screening at a participating site prior to surgical resection of the tumor. Patients will receive the standard of care, including radiation and Temodar therapy and two out of three will additionally receive DCVax-L, with the remaining one third receiving a placebo. Patients randomized to the placebo arm will have the option to receive DCVax-L in a crossover arm upon documented disease progression. (note: DCVax-L when used for patients with brain cancer is sometimes also referred to as DCVax-Brain)