IMMU-51. THE COMBINATION OF CCR2 ANTAGONIST AND PD-1 BLOCKADE PROLONGS SURVIVAL IN IMMUNE CHECKPOINT INHIBITOR RESISTANT GLIOMAS

摘要

INTRODUCTIONImmuno-therapy directed at the PD-1/PD-L1 axis has produced significant treatment advances in various human cancers. Unfortunately, this progress has not extended to glioblastoma, with recent clinical trials failing to show efficacy of anti-PD-1 monotherapy in recurrent tumors. Commonly employed murine glioma models exhibit varied responsiveness to anti-PD-1 monotherapy, e.g. GL261 gliomas are sensitive while KR158 tumors are resistant. Previously, we reported that combining PD-1 blockade with either chemokine receptor CCR2 deficiency or a CCR2 antagonist improved survival over anti-PD-1 monotherapy in GL261 gliomas. This was associated with reduced numbers of MDSCs within tumors. The current study evaluated the combination of PD-1 blockade and a novel CCR2 antagonist in anti-PD-1 resistant gliomas.