ATIM-22. PHASE I TRIAL OF DRUG RESISTANT IMMUNOTHERAPY: A FIRST-IN-CLASS COMBINATION OF MGMT-MODIFIEDγδ T CELLS AND TEMOZOLOMIDE CHEMOTHERAPY IN NEWLY DIAGNOSED GLIOBLASTOMA MULTIFORME

Abstract

Abstract INTRODUCTION Alkylating agents such as Temozolomide (TMZ) significantly upregulate stress-induced NKG2D ligands targeted by innate immune effector cells. Genetic modification of γδT cells with an MGMT-expressing lentivector abrogates TMZ-induced lymphodepletion allowing simultaneous chemotherapy and γδT cell therapy in a process we have termed Drug Resistant Immunotherapy (DRI) resulting in a significant improvement in long-term survival in patient-derived xenograft (PDXT) models of primary and recurrent GBM. We have now initiated a Phase I clinical trial of DRI in primary GBM (BB-IND-17928) to determine the safety of this approach. METHODS Effector γδT cells are manufactured from a fractional apheresis product obtained immediately prior to post-resection chemo/radiotherapy. Cultures are propagated in a Miltenyi Prodigy® bioreactor using media containing Zoledronic Acid and rhIL-12, transduced with a P140K-MGMT lentivector, maintained for up to 14 days, harvested, and cryopreserved. At the initiation of maintenance TMZ therapy, patients receive 150mg/m2 intravenous TMZ and 1 x 107 γδT cells delivered through a Rickham reservoir inserted into the tumor cavity at primary resection. Treatment frequency escalates from one to three 28-day cycles in a standard 3 x 3 design. RESULTS Closed system manufacturing in the Prodigy bioreactor produced 4.5 – 11.9 x 108 γδT cells (44–103 fold expansion) from the apheresis starting material (0.6–1.9% γδT cells) with vector copy numbers of 0.9 - 2.1 copies/cell and in vitro cytotoxicity against K562 44.3% - 77.9% at E:T 40:1. Products were successfully cryopreserved and retained in vivo potency against GBM PDXT in mice over single-agent TMZ (p= 0.0286). All cell products met sterility and identity criteria. CONCLUSIONS These findings show that genetically modified γδT cells can be manufactured to clinical scale under GMP compliance in an automated bioreactor and cryopreserved to produce multiple doses of functionally-competent γδT cells. Patient accrual will initiate in 2019.