Background: The inherent biologic specificity of immunotherapy offers the prospect of targeting neoplastic cells more precisely. Dendritic cells (DCs) are endowed with an extraordinary ability to activate CD4+ and CD8+ T-cells, and DCs loaded with antigens derived from tumor cells (CMV pp65-LAMP mRNA) have the potential to induce potent antitumor immunity. Furthermore, regulatory T-cells (TRegs) which induce a state of reversible immunosuppression in MG and can be functionally inactivated with anti-CD25 antibody (Ab), while dramatically enhance vaccine-induced immune responses. Our pilot group of 7 pts that received DC CMV vaccine with one dose of anti-CD25 Ab had median progression free survival (PFS) and overall survival (OS) of 23.5 months and 30.3 months respectively. There were no adverse events associated with the vaccine or anti-CD25 Ab therapy. Methods: Eligible are gross totally resected pts with newly diagnosed GBM. Pts undergo leukapheresis followed by standard of care radiation/temozolomide (XRT/TMZ) therapy. After completion of XRT/TMZ, up to 12 cycles of TMZ is administered. On Day 21 of the 1^st cycle of post-XRT TMZ Vaccine # 1 is administered. Vaccines #2-3 are given biweekly following vaccine #1. Anti-CD25 Ab (basiliximab) is given twice, one week before vaccines 1 and 2. In this dose escalation study two dose levels are examined: 20 or 40 mg. An additional vaccine is given with each cycle of TMZ to a total of 8. Pts were followed with serial MRIs until disease progression. Multiple time-point immuno-monitoring by kinetics of number of TRegs and pp65 specific T cells by INFγ ELISPOT is performed for each pt. Results: 21 pts are enrolled to Phase I and to date 8 pts (7 males) have received both administrations of basiliximab and are evaluable for the determination of maximum tolerated dose. 4 pts were screen failures. No DLT or adverse events attributable to treatment are observed thus far. Conclusions: Treatment with XRT/TMZ, DC vaccine and basiliximab was well tolerated. Clinical trial information: NCT00626483