Abstract

Adoptive T-cell therapies, where exogenous expression of a chimeric antigen receptor (CAR) confers cancer recognition, have shown significant promise in initial clinical trials. However, present adoptive immunotherapy Methods are limited by the need for manipulation of autologous patient T-cells. To permit such an approach in an allogeneic context, Transcription Activator-Like Effector Nucleases (TALENTM) have been used to simultaneously inactivate the endogenous T cell receptor and CD52, a cellular target for a lymphodepleting treatment. This approach reduces the risk of GVHD while permitting proliferation and activity of the introduced T lymphocytes in the presence of the immunosuppressive drug alemtuzumab. Electroporation of primary T cells with mRNA coding for the appropriate TALENTM result in double knock-out (dKO) frequencies of up to 70%. Furthermore, functional characterization demonstrates that the dKO cells are resistant to complement dependent lysis or in vivo depletion by alemtuzumab, and show no apparent potential for TCR-mediated activation. Finally, endowing the dKO cells with a CD19 CAR supports their capacity to kill CD19+ tumor targets as efficiently as unedited T-cells both in vitro and in vivo.

Disclosures:

Poirot:CELLECTIS THERAPEUTICS: Employment. Schiffer-Mannioui:CELLECTIS THERAPEUTICS: Employment. Philip:UCL Cancer Institute, London, United Kingdom: Employment. Derniame:CELLECTIS THERAPEUTICS: Employment. Gouble:CELLECTIS THERAPEUTICS: Employment. Chion-Sotinel:CELLECTIS THERAPEUTICS: Employment. Le Clerre:CELLECTIS THERAPEUTICS: Employment. Lemaire:CELLECTIS THERAPEUTICS: Employment. Grosse:CELLECTIS THERAPEUTICS: Employment. Cheung:UCL Cancer Institute, London, United Kingdom: Employment. Arnould:CELLECTIS THERAPEUTICS: Employment. Smith:CELLECTIS THERAPEUTICS: Employment. Pule:UCL Cancer Institute, London, United Kingdom: Employment. Scharenberg:CELLECTIS THERAPEUTICS: Employment.

Author notes

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Asterisk with author names denotes non-ASH members.