Phase I/II trial of combination of temozolomide chemotherapy and immunotherapy with fusions of dendritic and glioma cells in patients with glioblastoma

This trial was designed to evaluate the safety and clinical responses to a combination of temozolomide (TMZ) chemotherapy and immunotherapy with fusions of DCs and glioma cells in patients with glioblastoma (GBM). GBM patients were assigned to two groups: a group of recurrent GBMs after failing TMZ-chemotherapy against the initially diagnosed glioma (Group-R) or a group of newly diagnosed GBMs (Group-N). Autologous cultured glioma cells obtained from surgical specimens were fused with autologous DCs using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region. Toxicity, progression-free survival (PFS), and overall survival (OS) of this trial were evaluated. Expressions of WT-1, gp-100, and MAGE-A3, recognized as chemoresistance-associated peptides (CAP), were confirmed by immunohistochemistry of paraffin-embedded tumor samples. Patient's PBMCs of pre- and post-vaccination were evaluated by tetramer and ELISPOT assays. FC-immunotherapy was well tolerated in all patients. Medians of PFS and OS of Group-R (n = 10) were 10.3 and 18.0 months, and those of Group-N (n = 22) were 18.3 and 30.5 months, respectively. Up-regulation and/or cytoplasmic accumulation of CAPs was observed in the recurrent tumors of Group-R patients compared with their initially excised tumors. Specific immune responses against CAPs were observed in the tetramer and ELISPOT assays. The combination of TMZ-treatment leading to up-regulation and/or cytoplasmic accumulation of CAPs, with FC-immunotherapy as a means of producing specific immunity against CAPs, may safely induce anti-tumor effects in patients with GBM.