SLAMF7-CAR T cells eliminate myeloma and confer selective fratricide of SLAMF7+ normal lymphocytes

T Gogishvili, S Danhof… - Blood, The Journal …, 2017 - ashpublications.org
T Gogishvili, S Danhof, S Prommersberger, J Rydzek, M Schreder, C Brede, H Einsele…
Blood, The Journal of the American Society of Hematology, 2017ashpublications.org
SLAMF7 is under intense investigation as a target for immunotherapy in multiple myeloma.
In this study, we redirected the specificity of T cells to SLAMF7 through expression of a
chimeric antigen receptor (CAR) derived from the huLuc63 antibody (elotuzumab) and
demonstrate that SLAMF7-CAR T cells prepared from patients and healthy donors confer
potent antimyeloma reactivity. We confirmed uniform, high-level expression of SLAMF7 on
malignant plasma cells in previously untreated and in relapsed/refractory (R/R) myeloma …
Abstract
SLAMF7 is under intense investigation as a target for immunotherapy in multiple myeloma. In this study, we redirected the specificity of T cells to SLAMF7 through expression of a chimeric antigen receptor (CAR) derived from the huLuc63 antibody (elotuzumab) and demonstrate that SLAMF7-CAR T cells prepared from patients and healthy donors confer potent antimyeloma reactivity. We confirmed uniform, high-level expression of SLAMF7 on malignant plasma cells in previously untreated and in relapsed/refractory (R/R) myeloma patients who had received previous treatment with proteasome inhibitors and immunomodulatory drugs. Consequently, SLAMF7-CAR T cells conferred rapid cytolysis of previously untreated and R/R primary myeloma cells in vitro. In addition, a single administration of SLAMF7-CAR T cells led to resolution of medullary and extramedullary myeloma manifestations in a murine xenograft model in vivo. SLAMF7 is expressed on a fraction of normal lymphocytes, including subsets of natural killer (NK) cells, T cells, and B cells. After modification with the SLAMF7-CAR, both CD8+ and CD4+ T cells rapidly acquired and maintained a SLAMF7 phenotype and could be readily expanded to therapeutically relevant cell doses. We analyzed the recognition of normal lymphocytes by SLAMF7-CAR T cells and show that they induce selective fratricide of SLAMF7+/high NK cells, CD4+ and CD8+ T cells, and B cells. Importantly, however, the fratricide conferred by SLAMF7-CAR T cells spares the SLAMF7–/low fraction in each cell subset and preserves functional lymphocytes, including virus-specific T cells. In aggregate, our data illustrate the potential use of SLAMF7-CAR T-cell therapy as an effective treatment against multiple myeloma and provide novel insights into the consequences of targeting SLAMF7 for the normal lymphocyte compartment.
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