Evaluating in vivo efficacy – toxicity profile of TEG001 in humanized mice xenografts against primary human AML disease and healthy hematopoietic cells

Abstract

Backgroundγ9δ2T cells, which express Vγ9 and Vδ2 chains of the T cell receptor (TCR), mediate cancer immune surveillance by sensing early metabolic changes in malignant leukemic blast and not their healthy hematopoietic stem counterparts via the γ9δ2TCR targeting joined conformational and spatial changes of CD277 at the cell membrane (CD277J). This concept led to the development of next generation CAR-T cells, so-called TEGs: αβT cells Engineered to express a defined γδTCR. The high affinity γ9δ2TCR clone 5 has recently been selected within the TEG format as a clinical candidate (TEG001). However, exploring safety and efficacy against a target, which reflects an early metabolic change in tumor cells, remains challenging given the lack of appropriate tools. Therefore, we tested whether TEG001 is able to eliminate established leukemia in a primary disease model, without harming other parts of the healthy hematopoiesis in vivo.MethodsSeparate sets of NSG mice were respectively injected with primary human acute myeloid leukemia (AML) blasts and cord blood-derived human progenitor cells from healthy donors. These mice were then treated with TEG001 and mock cells. Tumor burden and human cells engraftment were measured in peripheral blood and followed up over time by quantifying for absolute cell number by flow cytometry. Statistical analysis was performed using non-parametric 2-tailed Mann-Whitney t-test.ResultsWe successfully engrafted primary AML blasts and healthy hematopoietic cells after 6–8 weeks. Here we report that metabolic cancer targeting through TEG001 eradicated established primary leukemic blasts in vivo, while healthy hematopoietic compartments derived from human cord-blood remained unharmed in spite of TEGs persistence up to 50 days after infusion. No additional signs of off-target toxicity were observed in any other tissues.ConclusionWithin the limitations of humanized PD-X models, targeting CD277J by TEG001 is safe and efficient. Therefore, we have initiated clinical testing of TEG001 in a phase I first-in-human clinical trial (NTR6541; date of registration 25 July 2017).Electronic supplementary materialThe online version of this article (10.1186/s40425-019-0558-4) contains supplementary material, which is available to authorized users.

TEG011 persistence averts extramedullary tumor growth without exerting off-target toxicity against healthy tissues in a humanized HLA-A*24:02 transgenic mice

“…These models partially overcome the absence of the natural ligand CD277J in mice 3,7,33 and allowed the initiation of a first‐in‐men study (NTR6541) 18,19,34 . With TEG011, we could utilize transgenic mice expressing human HLA‐A*24:02, 25 allowing thereby more extensive toxicity studies of TEG011 in different tissues as compared to TEG001 26,32 . Although we did not investigate all organs, and despite the fact that TEG011 did not persist until day 72 in the peripheral blood of all mice, we provide strong evidence that TEG011 does not induce toxicity against human HLA‐A*24:02 expressing nontumor healthy tissues.…”

“…Toxicity studies of compounds targeting metabolic changes remain a major challenge as such changes cannot be readily studied in detail in all organs 3 . Therefore, we proposed efficacy‐toxicity models for TEGs targeting joint spatial and conformational changes in CD277 (later referred as CD277J) 3 through a γ9δ2TCR (TEG001) by co‐incubating TEG001 with healthy and diseased tissues in an artificial 3D bone marrow niche 32 or in a mouse model where either healthy cord blood‐derived CD34 + progenitor or primary leukemia cells were engrafted 26 . These models partially overcome the absence of the natural ligand CD277J in mice 3,7,33 and allowed the initiation of a first‐in‐men study (NTR6541) 18,19,34 .…”

Development of Mast Cell and Eosinophil Hyperplasia and HLH/MAS-Like Disease in NSG-SGM3 Mice Receiving Human CD34+ Hematopoietic Stem Cells or Patient-Derived Leukemia Xenografts

“…The complexity of cell populations is compounded in studies combining multiple types of implanted human cells, as is often done for immunotherapy. 21,23,86 Such studies have been conducted in NSG mice, including the use of anti-PD1 74,93 and CAR-T 2,47 cell therapy. These studies have shown humanized mice to be a superior model in testing immunotherapies, and it is likely that similar studies in NSG-SGM3 mice are currently being conducted.…”

Spontaneous and Induced Animal Models for Cancer Research

“…Human acute myeloid leukemia (AML) animal models can be obtained via AML blasts and cord blood-derived human progenitor cell engraftment into NSG mice. The results are visible after 6-8 weeks, and various CAR T-cell therapies can be tested [220].…”