AIM:ERC1671 is an allogeneic/autologous therapeutic glioblastoma (GBM) vaccine - composed of whole, inactivated tumor cells mixed with tumor cell lysates derived from the patient and three GBM donors. METHODS:In this double-blinded, randomized, Phase II study bevacizumab-naive patients with recurrent GBM were randomized to receive either ERC1671 in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) (Leukine® or sargramostim) and cyclophosphamide plus bevacizumab, or placebo plus bevacizumab. Interim results: Median overall survival (OS) of patients treated with ERC1671 plus bevacizumab was 12 months. In the placebo plus bevacizumab group, median OS was 7.5 months. The maximal CD4+ T-lymphocyte count correlated with OS in the ERC1671 but not in the placebo group. CONCLUSION:The addition of ERC1671/GM-CSF/cyclophosphamide to bevacizumab resulted in a clinically meaningful survival benefit with minimal additional toxicity.