Enhancing Anti-Tumor Immunity and Responses to Immune Checkpoint Blockade By Suppressing Interleukin-10 in Chronic Lymphocytic Leukemia

B-cell Chronic Lymphocytic Leukemia (CLL) is the most common leukemia in the Western world, accounting for nearly one third of all leukemia cases. In CLL abnormal B-cells accumulate in the blood and lymphoid organs leading to serious immune dysfunction. This immune suppression is in part due to CLL-produced mediators that downregulate T-cell responses, such as the regulatory cytokine Interleukin-10 (IL-10). We previously found that eliminating T-cell IL-10 signaling enhanced their ability to control CLL growth in vivo. Therefore, we investigated the potential for IL-10 blockade to enhance the anti-tumor activity of CD8+ T-cells. In our studies we use human CLL cells as well as the Eμ-Tcl1 mouse model of CLL, in which the oncogene Tcl1 is expressed under the immunoglobulin VH promoter and µ-enhancer. IL-10 production by CLL cells depends on the transcription factor Sp1, and we found that the Sp1 inhibitor mithramycin (MTM) suppresses CLL IL-10 production. However, MTM is not well tolerated in vivo, so we synthesized novel, less toxic analogues of MTM to test for IL-10 suppression. One of these MTM analogues similarly suppresses mouse and human CLL IL-10 with little to no effect on effector T-cell cytokines and viability. Therefore, we treated mice with this analogue in the adoptive transfer model of Eμ-Tcl1, and later combined this with anti-PD-L1 checkpoint blockade to determine its effects on anti-tumor immunity. Here we show that this MTM analogue enhances the efficacy of anti-CLL T-cells in vivo by suppressing CLL IL-10 production, allowing for increased CD8+ T-cell proliferation, effector memory cell prevalence, and CD8+ interferon-γ (IFN-γ) production. Treatment slowed the growth of Eμ-TCL1 CLL cells in the spleen and blood and reduced the spread of CLL to the bone marrow. Furthermore, suppressing IL-10 in this manner improved responses to anti-PD-L1 treatment, decreasing the burden of CLL cells and the functionality of CD8+ T-cells in comparison to anti-PD-L1 alone. The overall number and frequency of CD8+ T-cells was higher in double treated mice, with more IFN-γ+ CD8+ cells, more effector memory cells, and fewer exhausted T-cells. This paradigm shifting approach is novel as current therapies for CLL do not target IL-10 and it may increase the efficacy of T-cell-based immunotherapies in human CLL. T-cell-based immunotherapies have experienced limited success in trials with CLL, and since there is no cure for this disease, our approach may provide a new avenue for combination therapies. Moreover, IL-10 blockade could be applicable to other B-cell malignancies and even solid tumors where T-cell suppression plays a significant role. Disclosures Hildebrandt: Axim Biotechnologies: Equity Ownership; Kite Pharma: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other; Sangamo: Equity Ownership; Novartis: Equity Ownership; Axim Biotechnologies: Equity Ownership; Juno Therapeutics: Equity Ownership; Kite Pharma: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Novartis: Equity Ownership; Insys Therapeutics: Equity Ownership; Abbvie: Equity Ownership; GW Pharmaceuticals: Equity Ownership; Cardinal Health: Equity Ownership; Immunomedics: Equity Ownership; Endocyte: Equity Ownership; Clovis Oncology: Equity Ownership; Cellectis: Equity Ownership; Aetna: Equity Ownership; CVS Health: Equity Ownership; Celgene: Equity Ownership; Bluebird Bio: Equity Ownership; Bristol-Myers-Squibb: Equity Ownership; crispr therapeutics: Equity Ownership; IDEXX laboratories: Equity Ownership; Johnson & Johnson: Equity Ownership; Pfizer: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Procter & Gamble: Equity Ownership; Vertex: Equity Ownership; Bayer: Equity Ownership; Scotts-Miracle: Equity Ownership; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Takeda: Research Funding; Pharmacyclics: Research Funding; Astellas: Other: Travel.

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Predictors of T Cell Expansion and Clinical Responses Following B-Cell Maturation Antigen-Specific Chimeric Antigen Receptor T Cell Therapy (CART-BCMA) for Relapsed/Refractory Multiple Myeloma (MM)

Blood ◽

10.1182/blood-2018-99-119665 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1974-1974 ◽

Cited By ~ 2

Author(s):

Adam D. Cohen ◽

J. Joseph Melenhorst ◽

Alfred L. Garfall ◽

Simon F Lacey ◽

Megan Davis ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Advisory Committees ◽

Car T ◽

Equity Ownership

Abstract Background: Relapsed/refractory (rel/ref) MM is associated with progressive immune dysfunction, including reversal of CD4:CD8 T cell ratio and acquisition of terminally-differentiated T cell phenotypes. BCMA-directed CAR T cells have promising activity in MM, but the factors that predict for robust in vivo expansion and responses are not known. In a phase 1 study of CART-BCMA (autologous T cells expressing a human BCMA-specific CAR with CD3ζ/4-1BB signaling domains) in refractory MM patients (median 7 priors, 96% high-risk cytogenetics), we observed partial response (PR) or better in 12/25 (47%) (Cohen et al, ASH 2017, #505). Recently, we demonstrated in CLL pts receiving CD19-directed CAR T cells that certain T cell phenotypes prior to generation of the CAR T product were associated with improved in vivo expansion and clinical outcomes (Fraietta et al, Nat Med 2018). We thus sought to identify pre-treatment clinical or immunological features associated with CART-BCMA expansion and/or response. Methods: Three cohorts were enrolled: 1) 1-5 x 108 CART cells alone; 2) cyclophosphamide (Cy) 1.5 g/m2 + 1-5 x 107 CART cells; and 3) Cy 1.5 g/m2 + 1-5 x 108 CART cells. Phenotypic analysis of peripheral blood (PB) and bone marrow (BM) mononuclear cells, frozen leukapheresis aliquots, and phenotype and in vitro kinetics of CART-BCMA growth during manufacturing were performed by flow cytometry. CART-BCMA in vivo expansion was assessed by flow cytometry and qPCR. Responses were assessed by IMWG criteria. Results: Responses (≥PR) were seen in 4/9 pts (44%, 1 sCR, 2 VPGR, 1 PR) in cohort 1; 1/5 (20%, 1 PR) in cohort 2; and 7/11 (64%, 1 CR, 3 VGPR, 3 PR) in cohort 3. As of 7/9/18, 3/25 (12%) remain progression-free at 11, 14, and 32 months post-infusions. As previously described, responses were associated with both peak in vivo CART-BCMA expansion (p=0.002) as well as expansion over first month post-infusion (AUC-28, p=0.002). No baseline clinical or MM-related characteristic was significantly associated with expansion or response, including age, isotype, time from diagnosis, # prior therapies, being quad- or penta-refractory, presence of del 17p or TP53 mutation, serum hemoglobin, BM MM cell percentage, MM cell BCMA intensity, or soluble BCMA concentration. Treatment regimen given before leukapheresis or CART-BCMA infusions also had no predictive value. We did find, however, that higher CD4:CD8 T cell ratios within the leukapheresis product were associated with greater in vivo CART-BCMA expansion (Spearman's r=0.56, p=0.005) and clinical response (PR or better; p=0.014, Mann-Whitney). In addition, and similar to our CLL data, we found that a higher frequency of CD8 T cells within the leukapheresis product with an "early-memory" phenotype of CD45RO-CD27+ was also associated with improved expansion (Spearman's r=0.48, p=0.018) and response (p=0.047); Analysis of manufacturing data confirmed that higher CD4:CD8 ratio at culture start was associated with greater expansion (r=0.41, p=0.044) and, to a lesser degree, responses (p=0.074), whereas absolute T cell numbers or CD4:CD8 ratio in final CART-BCMA product was not (p=NS). In vitro expansion during manufacturing did associate with in vivo expansion (r=0.48, p=0.017), but was not directly predictive of response. At the time of CART-BCMA infusion, the frequency of total T cells, CD8+ T cells, NK cells, B cells, and CD3+CD56+ cells within the PB or BM was not associated with subsequent CART-BCMA expansion or clinical response; higher PB and BM CD4:CD8 ratio pre-infusion correlated with expansion (r=0.58, p=0.004 and r=0.64, p=0.003, respectively), but not with response. Conclusions: In this study, we found that CART-BCMA expansion and responses in heavily-pretreated MM patients were not associated with tumor burden or other clinical characteristics, but did correlate with certain immunological features prior to T cell collection and manufacturing, namely preservation of normal CD4:CD8 ratio and increased frequency of CD8 T cells with a CD45RO-CD27+ phenotype. This suggests that patients with less dysregulated immune systems may generate more effective CAR T cell products in MM, and has implications for optimizing patient selection, timing of T cell collection, and manufacturing techniques to try to overcome these limitations in MM patients. Disclosures Cohen: Celgene: Consultancy; Novartis: Research Funding; Oncopeptides: Consultancy; Janssen: Consultancy; Poseida Therapeutics, Inc.: Research Funding; Bristol Meyers Squibb: Consultancy, Research Funding; Kite Pharma: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; Seattle Genetics: Consultancy. Melenhorst:Parker Institute for Cancer Immunotherapy: Research Funding; novartis: Patents & Royalties, Research Funding; Casi Pharmaceuticals: Consultancy; Incyte: Research Funding; Shanghai UNICAR Therapy, Inc: Consultancy. Garfall:Amgen: Research Funding; Kite Pharma: Consultancy; Bioinvent: Research Funding; Novartis: Research Funding. Lacey:Novartis Pharmaceuticals Corporation: Patents & Royalties; Parker Foundation: Research Funding; Tmunity: Research Funding; Novartis Pharmaceuticals Corporation: Research Funding. Davis:Novartis Institutes for Biomedical Research, Inc.: Patents & Royalties. Vogl:Karyopharm Therapeutics: Consultancy. Pruteanu:Novartis: Employment. Plesa:Novartis: Research Funding. Young:Novartis: Patents & Royalties, Research Funding. Levine:Novartis: Consultancy, Patents & Royalties, Research Funding; CRC Oncology: Consultancy; Incysus: Consultancy; Tmunity Therapeutics: Equity Ownership, Research Funding; Brammer Bio: Consultancy; Cure Genetics: Consultancy. June:Novartis Pharmaceutical Corporation: Patents & Royalties, Research Funding; Immune Design: Membership on an entity's Board of Directors or advisory committees; Tmunity Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Novartis Pharmaceutical Corporation: Patents & Royalties, Research Funding; Immune Design: Membership on an entity's Board of Directors or advisory committees; Celldex: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tmunity Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Stadtmauer:Takeda: Consultancy; Celgene: Consultancy; Amgen: Consultancy; AbbVie, Inc: Research Funding; Janssen: Consultancy. Milone:Novartis: Patents & Royalties.

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NME-2 Protein Functions as a Tumour Associated Antigen in HLA-A2+ Cells and Is Over Expressed in CML Via a Bcr/Abl Dependent Post Transcriptional Mechanism.

Blood ◽

10.1182/blood.v114.22.3266.3266 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3266-3266

Author(s):

Sabine Tschiedel ◽

Melanie Adler ◽

Karoline Schubert ◽

Annette Jilo ◽

Enrica Mueller ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Cell Response ◽

Research Funding ◽

Kinase Activity ◽

T Cell Response ◽

Advisory Committees

Abstract Abstract 3266 Poster Board III-1 Introduction: NmE2 (Nm23-H2, NDP kinase B) is one of a family of proteins that catalyze the transfer of gamma-phosphate between nucleoside-triphosphates and diphosphates. The two major family members, NmE1 and NmE2 are strongly implicated in the control of differentiation, proliferation, migration and apoptosis via interactions which are often independent of their kinase activity, NmE2 being a transcriptional activator of the c-myc gene. We recently identified NmE2 as a tumour associated, HLA-A32+ restricted, antigen in a patient with CML and found the protein (but not the mRNA) to be generally over expressed in CML but not in other haematological malignancies. We also detected a specific T-cell response in peripheral blood cells of a patient 5 years after transplantation. This identifies NmE2 as a potential target for both molecular and immunotherapy of CML. However, the development of immunotherapeutic approaches will depend on the ability of NmE2 to function as a tumour antigen in common HLA backgrounds. The aims of this study were firstly to investigate the antigenicity of NmE2 in the HLA-A2 background (which accounts for more than 50% of the Caucasian population), and secondly to characterise the regulatory relationship between Bcr/Abl and NmE2 using a cell line model of CML. Materials and Methods: 5 nonameric NmE2 peptides with predicted anchor amino acids for HLA-A2 were loaded at concentrations of 10μM separately onto HLA-A2 expressing antigen presenting cells. Elispot Assays were carried out with CD8+ MLLCs (for the identification of antigenic peptides) or CD8+ cells isolated directly from a CML patient at different time points after HCT. Ba/F3 cells stably expressing wild type and mutant forms of Bcr/Abl were treated with imatinib and nilotinib (0 – 10 μM) for 48h. Bcr/Abl activity was assessed by FACS using antibodies specific for the phosphorylated forms of CrkL and Stat5. NmE2 and c-Myc protein were detected by immunocytochemistry and Western blotting with specific antibodies [Santa Cruz, clones L-16 and 9E10 respectively]. Levels of nme2 and c-myc mRNA were determined by quantitative real time PCR. Results: Full length NmE2 protein and 2 of 5 HLA-A2 anchor-containing peptides tested (NmE2132–140 and NmE2112–120) were specifically recognized by the HLA-A2+ CD8+ MLLC, demonstrating the antigenicity of NmE2 in the HLA-A2 background in vitro. Furthermore, while CD8+ T-cells from a transplanted HLA-A2+ CML patient showed little or no specific reactivity in the first 10 months after HCT, a distinct reactivity (up to 0.6 % NmE2 reactive CD8+ T cells) became apparent at later stages, consistent with the development of an immune response against NmE2-expressing cells in vivo. The patient remained negative for bcr/abl transcripts throughout this period. BA/F3 Bcr/Abl cells expressed increased levels of NmE2 protein (but not mRNA) compared to the parent BA/F3 line. Interestingly, treatment with imatinib or nilotinib reduced NmE2 protein expression in BA/F3 Bcr/Abl, but not in cells expressing Bcr/Abl mutants resistant to the respective inhibitors. Treatment of BA/F3 Bcr/Abl cells with the PI3K inhibitor Ly294002 resulted in reduced Bcr/Abl activity and a corresponding reduction in both c-Myc and NmE2 protein levels, without affecting mRNA levels. Conclusion: The over expression of NmE2 is closely linked to Bcr/Abl kinase activity, the predominant level of regulation being post-transcriptional and dependent on PI-3K activity. The NmE2 protein is restricted by HLA-A2 as well as by HLA-A32. The development of an NmE2-specific T-cell response in a CML patient after stem cell transplantation suggests that NmE2 functions as a tumour antigen in HLA-A2+ patients in vivo and may be relevant to the long term immune control of CML. NmE2 is therefore a promising candidate for the development of new immunotherapeutic strategies for the treatment of CML. Disclosures: Lange: BMS: Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Niederwieser:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Research Funding.

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Vecabrutinib Is Efficacious In Vivo in a Preclinical CLL Adoptive Transfer Model

Blood ◽

10.1182/blood-2018-99-116664 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1868-1868 ◽

Cited By ~ 1

Author(s):

Billy Michael Chelliah Jebaraj ◽

Annika Scheffold ◽

Eugen Tausch ◽

Judith A. Fox ◽

Pietro Taverna ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Tumor Burden ◽

Transfer Model ◽

Advisory Committees

Abstract B cell receptor signaling (BCR) in chronic lymphocytic leukemia (CLL) drives tumor cell proliferation and survival. Inhibition of Bruton's tyrosine kinase (BTK), a key enzyme in the BCR pathway, has proved to be efficacious even in poor-risk and chemo-refractory patients. However resistance to the BTK inhibitor ibrutinib has been shown to emerge in a subset of CLL patients. Of importance, the C481S BTK mutation conferred resistance by preventing the covalent binding of ibrutinib to its target cysteine 481 in BTK. Vecabrutinib (formerly known as SNS-062, a succinate salt) is a novel, highly potent, next generation noncovalent BTK inhibitor which demonstrated biochemical and cellular activity against C481S BTK mutant in vitro. However, the efficacy of vecabrutinib and its impact on the T-cell microenvironment has not been studied in in vivo preclinical CLL models. In the present study, the efficacy of vecabrutinib was investigated using the Eµ-TCL1 adoptive transfer model. Mice were randomized to treatment with either 40mg/kg vecabrutinib succinate, twice daily by oral gavage (n=6) or vehicle control (n=6). The mice were sacrificed after 2 weeks of treatment and changes in tumor burden as well as alterations in T-cell microenvironment were analysed in detail. Treatment with vecabrutinib decreased tumor burden as observed by a significant decrease in WBC count (36.5 vs. 17.1 giga/L; P=0.002), spleen weight (median 0.56g vs. 0.31g; P=0.005) and liver weight (median 1.5g vs. 1.2g; P=0.005) compared to vehicle treatment. Correspondingly, the CD5+ CD19+ tumor cells were significantly decreased in blood (P=0.002) and spleen (P=0.002) while no significant difference was observed in bone marrow (P=0.818) upon treatment with vecabrutinib. Since BTK inhibition is known to reshape the tumor microenvironment, we studied the impact of vecabrutinib specifically on T-cell subsets. Firstly, no difference in the proportions of CD4 or CD8 expressing T-cells was observed in mice treated with vehicle or vecabrutinib. However, of interest, the percentage of CD4+ CD25+ FoxP3+ regulatory T cells (Tregs) were significantly decreased upon treatment with vecabrutinib in peripheral blood (P=0.026) and spleen (P=0.009). The decrease in Tregs was due to reduced proliferation of these cells upon exposure to the drug as measured by Ki-67 staining. Also, the Tregs expressing the maturation and activation markers such as CD103 and GITR were significantly decreased in blood and spleen upon drug treatment. Further, we analysed the changes in CD8 T-cell subsets following treatment with vecabrutinib. Treatment with the drug resulted in expansion of the CD127+ CD44- naïve CD8 T-cells in blood, bone marrow and spleen (all P values 0.002) while the CD127+ CD44+ memory CD8 T-cells were significantly decreased in bone marrow and spleen (all P values 0.009). Also, the CD127low CD44int-hi effector CD8 T-cells were decreased in blood (P=0.004), bone marrow (P=0.004) and spleen (P=0.002) upon vecabrutinib treatment. Therefore, vecabrutinib treatment did not alter the percentage of CD4+ and CD8+ T cells in mice however, significant changes in the subset composition of the CD4 and CD8 T cells were observed. Lastly, to analyse the impact of vecabrutinib on survival, a cohort of mice (n=12) were transplanted with 5 million splenic tumor cells isolated from Eµ-TCL1 transgenic mice. After allowing for engraftment, the mice were randomized to treatment with the drug (n=6) or vehicle (n=6). Of note, the mice treated with the drug showed a significant increase in survival (median 35 days from transplant; P<0.001) compared to treatment with vehicle (median 28 days). In summary, vecabrutinib was efficacious in vivo in a preclinical CLL adoptive transfer model, decreasing tumor burden in different organs and significantly improving survival. Treatment with the drug altered the T-cell architecture in vivo. Of interest, the immunosuppressive Tregs, which protect the tumor from immune surveillance were decreased in various tissue compartments; however, a decrease in the effector CD8 T cells might impact anti-tumor immunity if there is a consistent effect upon drug treatment. Vecabrutinib antitumor activity and effects on T-cell populations in vivo in this preclinical CLL model are intriguing, merits further investigation and supports the ongoing phase 1b/2 study in patients with previously treated B-lymphoid malignancies (NCT03037645). Disclosures Tausch: AbbVie: Consultancy, Other: Travel grants; Celgene: Consultancy, Other: Travel grants; Gilead: Consultancy, Other: Travel grants. Fox:Sunesis Pharmaceuticals: Employment; Amphivena Therapeutics: Employment. Taverna:Sunesis Pharmaceuticals: Employment. Stilgenbauer:Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmcyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Single Cell RNA Sequencing Identifies Transcriptional Programs That Enhance Anti-Tumor Function of Transgenic CD4+ T Cells Redirected with TCR and CD8αβ

Blood ◽

10.1182/blood-2019-124714 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 250-250

Author(s):

Jan A Rath ◽

Gagan Bajwa ◽

Benoit Carreres ◽

Isabelle Gruber ◽

Elisabeth Hoyer ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Leukemia Cells ◽

Advisory Committees ◽

Equity Ownership

Introduction:Transgenic co-expression of a major histocompatibility complex class I restricted tumor associated antigen specific TCR and CD8αβ (TCR8) has been previously proposed as a strategy to redirect CD4+ T cells to tumors. However, it is unknown whether forced TCR8 expression induces more fundamental transcriptional consequences in both CD4+ and CD8+ T cells, and whether T cell lineage origin affects this outcome. Here we deeply interrogate the effects of transgenic TCR and TCR8 in human CD4+ and CD8+ T cells upon leukemia challenge by single cell RNA sequencing (scRNAseq) and investigate T cell function in vitro and in vivo. We identify profound changes of gene expression that have significant functional consequences. Methods:A previously characterized HLA-A*02:01 restricted survivin-specific TCR was used (Arber et al, JCI, 2015 Jan;125(1):157-68) and a new polycistronic vector with this TCR and CD8αβ was generated. CD4+ and CD8+ T cells were isolated and scRNAseq (25'474 cells in total) was performed on (1) freshly isolated cells, (2) retrovirally transduced (TCR or TCR8) expanded cells, and (3) TCR+CD8+, TCR8+CD8+ and TCR8+CD4+ T cells co-cultured with BV173 leukemia cells (HLA-A*02:01+survivin+). scRNAseq results were cross-validated in independent experiments with FACS analysis of selected markers, in vitro stress-killing assays, analysis of cytokine production, and assessment of anti-tumor function in vivo in xenograft mice. Results:CD4+ T cells only killed BV173 leukemia cells when redirected with TCR8 but not with TCR alone (p=0.0004, n=7), while killing by TCR+CD8+ and TCR8+CD8+ T was comparable (p=NS). To explore some of the possible underlying mechanisms, we used dimensionality reduction and unsupervised clustering of the scRNASeq data and identified 19 distinct cell clusters. CD4+ and CD8+ lineage origin clearly separated the samples, but separation by transgene type only became apparent upon co-culture. Analyzing differentially expressed genes, we found that co-cultured samples contained clusters with high expression of cytotoxic markers but with significant differences between CD4+ and CD8+ lineages (e.g. transcription of GZMB in CD4+ T cells and GNLY, NKG7, GZMK in CD8+ T cells). Next, we analyzed which genes were upregulated from the expanded to co-cultured states. Co-cultured TCR8+CD4+ T cells had more upregulated genes with a broader diversity compared to TCR+CD8+ or TCR8+CD8+ T cells. Among these upregulated pathways were cytotoxicity, co-stimulation, oxidative phosphorylation, NFkB regulation, cell growth and transcription factors. TCR8+CD4+ T cells also retained a less differentiated phenotype (e.g. high IL7R, SELL, CCR7, CXCR4) with preservation of replicative potential. Furthermore, co-cultured TCR8+CD4+ T cells expressed more co-stimulatory and less activation/ exhaustion markers. In addition, co-cultured TCR8+CD4+ T cells heavily relied on oxidative phosphorylation and had higher mitochondrial activity compared to co-cultured TCR+ or TCR8+ CD8+ T cells. In stress co-cultures with multiple rounds of tumor challenge, TCR8+CD4+ T cells outperformed TCR+CD8+ T cells (number of killings TCR8+CD4+ vs TCR+CD8+: 3.3±0.5 vs 1.3±1.1, p=0.01, n=7), but were comparable to TCR8+CD8+ T cells (TCR8+CD4+ vs TCR8+CD8+: 3.3±0.5 vs 2±1.4,p=NS, n=7). TCR8+CD4+ T cells expanded significantly better than TCR+CD8+ T cells (p=0.002) and TCR8+CD8+ T cells (p=0.015) and produced TH1 type cytokines. In the xenograft mouse model, we observed significant BV173 leukemia control in mice treated with TCR+CD8+ T cells compared to controls (NT), and further enhancement in mice treated with TCR8+CD8+ T cells (NT vs TCR: p=0.0002, NT vs TCR8: p<0.0001, TCR vs TCR8: p=0.01, n=5). TCR8+CD4+ T cells also significantly delayed leukemia progression compared to TCR+CD4+ or NT T cells (p=0.001, n=5). Conclusion:Transgenic TCR8 expression has previously been proposed as a strategy to enhance TCR-pMHC recognition. Here we identify profound transcriptional changes involving multiple pathways that are important for sustained anti-tumor function upon adoptive T cell transfer in vivo, such as cytotoxicity, co-stimulation, cell cycle and metabolism. Our results point towards previously unrecognized mechanisms by which TCR8 transgenes mediate their beneficial effect in both CD4+ and CD8+ T cells. Disclosures Brenner: T Scan: Membership on an entity's Board of Directors or advisory committees; Marker Therapeutics: Equity Ownership; Allovir: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Equity Ownership; Memgen: Membership on an entity's Board of Directors or advisory committees; Allogene: Membership on an entity's Board of Directors or advisory committees. Arber:Cell Medica: Patents & Royalties.

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The Defective Proliferation of Vgamma9Vdelta2 T Cells to Zoledronic Acid In Chronic Lymphocytic Leukemia (CLL) Is a Powerful Time to First Treatment (TFT) Predictor Associated with the IGHV Mutational Status

Blood ◽

10.1182/blood.v116.21.3602.3602 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3602-3602

Author(s):

Marta Coscia ◽

Candida Vitale ◽

Silvia Peola ◽

Chiara Riganti ◽

Daniela Angelini ◽

...

Keyword(s):

T Cells ◽

Zoledronic Acid ◽

Board Of Directors ◽

Research Funding ◽

Lymphocytic Leukemia ◽

Effector Memory ◽

Advisory Committees ◽

Mutational Status ◽

Intermediate Metabolites ◽

Stimulation Of

Abstract Abstract 3602 The clinical course of chronic lymphocytic leukemia (CLL) depends on the intrinsic tumor cell features but also on the interactions between tumor cells, local microenvironment and host immunity. The interplay between CLL cells and conventional αβ T cells has already been investigated in details, whereas very little is known about the role of Vgamma9Vdelta2 T cells. These cells have intrinsic antitumor properties which can be further enhanced by stimulation with aminobisphosphonates such as zoledronic acid (ZA) via monocytes or other antigen-presenting cells. ZA targets the mevalonate (Mev) pathway and induces the intracellular accumulation and release of intermediate metabolites, like isopentenyl pyrophosphate (IPP), which are very similar to the natural ligands of Vgamma9Vdelta2 T cells. In this study we have performed a phenotypic and functional analysis of Vgamma9Vdelta2 T cells in 93 untreated CLL patients and correlated the results with intrinsic CLL cell features and clinical outcome. Stimulation of peripheral blood mononuclear cells with ZA induced Vgamma9Vdelta2 T cell proliferation in 47/93 patients (responders, R), but not in 46/93 patients (non-responders, NR). Vgamma9Vdelta2 T-cell subset distribution of R CLL was similar to healthy donors, whereas effector memory (EM) and terminally differentiated effector memory (TEMRA) cells predominated in NR CLL. A significant association was found between the R/NR status of Vgamma9Vdelta2 T cells and the mutational status of the tumor IGHV genes: 77% of R patients were M, whereas 70% of UM patients were NR. To test the hypothesis that this difference reflected a different activity of the Mev pathway in M and UM CLL cells, we performed a bioinformatic elaboration of data obtained from gene expression profiling of CLL cells and a biochemical quantification of the Mev pathway in CLL cells including the intermediate metabolites farnesyl pyrophosphate (FPP) and IPP, and the final product cholesterol. The Mev pathway was significantly more active in UM than in M CLL cells, suggesting that the IPP overproduction by UM CLL cells is responsible for a chronic stimulation of Vgamma9Vdelta2 T cells leading to their differentiation into EM and TEMRA cells. This biochemical-driven immunoediting process has clinical implications. After a median follow-up of 46 months from diagnosis, univariate analysis identified R status as a predictor of reduced TFT (NR: 59 months vs R: not reached; p=0.01). The R/NR status also allows to further identify two subsets in UM CLL patients (R-UM and NR-UM) with significantly different TFT (NR-UM: 32 months vs R-UM: not reached; p=0.02). In multivariate analysis, Binet stage (P=0.027), IGHV mutational status (p=0.016), R/NR status (p=0.007), high and low-risk cytogenetic abnormalities (p<0.001) and lymphocytosis at the time of diagnosis (p<0.001) were independent TFT predictors. In conclusion, we have identified a novel TFT predictor based on a putative interaction between the Mev pathway of CLL cells and Vgamma9Vdelta2 T cells. These results further strengthen the importance of tumor-host immune interactions in CLL evolution. Disclosures: Boccadoro: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Massaia:Novartis: Honoraria, Research Funding.

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CD4+ T Cell Fate in Multiple Myeloma

Blood ◽

10.1182/blood-2018-99-117674 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4494-4494

Author(s):

Rachel Elizabeth Cooke ◽

Jessica Chung ◽

Sarah Gabriel ◽

Hang Quach ◽

Simon J. Harrison ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Research Funding ◽

Flow Cytometric Analysis ◽

Advisory Committees ◽

Mitochondrial Mass ◽

Flow Cytometric

Abstract The average incidence of multiple myeloma (MM) is in the 7th decade that coincides with the development of immunosenescence and thymic atrophy, meaning that lymphocyte recovery after lymphopenia-inducing therapies (most notably autologous stem cell transplant, ASCT) is largely reliant on homeostatic proliferation of peripheral T cells rather than replenishing the T cell pool with new thymic emigrants. We have previously shown that there is a significant reduction in circulating naïve T cells with a reciprocal expansion of antigen-experienced cells from newly diagnosed MM (NDMM) to relapsed/refractory disease (RRMM). This results in a reduced TCR repertoire and the accumulation of senescence-associated secretory phenotype cytotoxic T cells, which maintain the ability to produce IFNγ but lose proliferative potential. A reduction in CD4:8 ratio is also a characteristic finding in MM with disease progression, which can be explained by high IL-15 levels in lymphopenic states that preferentially drive expansion of CD8+ memory T cells. We wanted to further evaluate what changes were occurring in the CD4+ T cell population with disease progression in MM. We analyzed paired peripheral blood (PB) samples from patients with NDMM and RRMM, and compared with age-matched normal donors (ND). In the NDMM cohort, we examined T cells from PB samples at baseline, after 4 cycles of lenalidomide and dexamethasone (len/dex), and after ASCT; and in the RRMM cohort samples from baseline and after 6 cycles of len/dex. We firstly confirmed in flow cytometric analysis of T cells at serial intervals in NDMM patients that the reduction in circulating naïve T cells and in CD4:8 ratio occurs post ASCT and does not recover by time of last follow-up. We next utilised RNA-seq to analyse differences in CD4+ T cells from NDMM, RRMM and ND. CD4+ T cells from RRMM showed downregulation of cytosolic ribosomal activity but maintenance of mitochondrial ribosomal activity and significant upregulation of pathways involved with calcium signalling. To this end, we evaluated mitochondrial biogenesis and metabolic pathways involved with mitochondrial respiration. Flow cytometric analysis of mitochondrial mass showed a marked increase in RRMM compared with ND, in keeping with a shift towards memory phenotype. Key rate-limiting enzymes in fatty acid β-oxidation (CPT1-A, ACAA2 and ACADVL) were all significantly increased in RRMM compared with ND. To analyse whether these cells were metabolically active, we also measured mitochondrial membrane potential and reactive oxygen species (ROS), gating on cells with high mitochondrial mass. Mitochondrial membrane potential was significantly increased in RRMM compared with ND, although ROS was reduced. The significance of this is not clear, as ROS are not only implicated in cell senescence and activation-induced cell death, but are also positively involved in tyrosine kinase and PI3K-signalling pathways. PD-1 has been shown to play a role in transitioning activated CD4+ T cells from glycolysis to FAO metabolism, and elevating ROS in activated CD8+ T cells. We analysed PD-1 expression on T cells in RRMM and at treatment intervals in NDMM (as described earlier). The proportion of CD4+ and CD8+ T cells expressing PD-1 was increased 4-6 months post-ASCT and remained elevated in CD4+ T cells 9-12 months post-ASCT, but normalised to baseline levels in CD8+ T cells. Increased PD-1 expressing CD4+ T cells was also evident in RRMM patient samples. This may suggest that in the lymphopenic state, PD-1 expression enhances longevity in a subset of CD4+ T cells by promoting reliance on mitochondrial respiration; however, their ability to undergo homeostatic proliferation is impaired. In CD8+ T cells, high PD-1 expression may lead to cell death via ROS accumulation, and these cells do not persist. ASCT remains a backbone of myeloma treatment in medically fit patients. However, this leads to significant permanent defects in the T cell repertoire, which may have unintended adverse outcomes. Additionally, T cells post-ASCT may not be metabolically adequate for the production of CAR-T cells, nor respond to checkpoint blockade therapies. Disclosures Quach: Amgen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Sanofi Genzyme: Research Funding; Janssen Cilag: Consultancy. Harrison:Janssen-Cilag: Other: Scientific advisory board. Prince:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Phase 1/2 Study of Nexi-001 Donor-Derived Multi-Antigen Specific CD8+ T Cells for the Treatment of Relapsed Acute Myeloid Leukemia (AML) after Allogeneic Hematopoietic Transplantation

Blood ◽

10.1182/blood-2021-152419 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 4819-4819

Author(s):

Monzr M. Al Malki ◽

Sumithira Vasu ◽

Dipenkumar Modi ◽

Miguel-Angel Perales ◽

Lucy Y Ghoda ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Phase 1 ◽

Clinical Activity ◽

Advisory Committees ◽

Over Time

Abstract Patients who relapse after allogeneic HCT have a poor prognosis and few effective treatment options. Responses to salvage therapy with donor lymphocyte infusions (DLI) are driven by a graft versus leukemia (GvL) effect. However, relapses and moderate to severe graft versus host disease (GVHD) are common. Therapies that increase the GvL effect without inducing GVHD are needed. The NEXI-001 study is a prospective, multicenter, open-label phase 1/2 trial designed to characterize the safety, immunogenic, and antitumor activity of the NEXI-001 antigen specific T-cell product. This product is a donor-derived non-genetically engineered therapy that consists of populations of CD8+ T cells that recognize HLA 02.01-restricted peptides from the WT1, PRAME, and Cyclin A1 antigens. These T cells consist of populations with key memory phenotypes, including stem-like memory, central memory, and effector memory cells, with a low proportion (<5%) of potentially allogeneic-reactive T-naïve cells. Patients enrolled into the first cohort of the dose escalation phase received a single infusion of 50 million (M) to 100M cells of the NEXI-001 product. Bridging anti-AML treatment was permitted during the manufacture of the cellular product with a wash-out period of at least 14 days prior to lymphodepletion (LD) chemotherapy (intravenous fludarabine 30 mg/m 2 and cyclophosphamide 300 mg/m 2) that was administered on Days -5, -4, and -3 prior to the infusion of the NEXI-001 product up to 72 hours later (Day1). Lymphocyte recovery to baseline levels occurred as early as three days after the NEXI-001 product infusion with robust CD4 and CD8 T cell reconstitution after LD chemotherapy. NEXI-001 antigen specific T cells were detectable in peripheral blood (PB) by multimer staining and were found to proliferate over time and to traffic to bone marrow. The phenotype composition of detectable antigen specific T cells at both sites was that of the infused product. T-cell receptor (TCR) sequencing assays revealed T cell clones in the NEXI-001 product that were not detected in PB of patients tested at baseline. These unique clones subsequently expanded in PB and bone marrow (BM) and persisted over time. Neutrophil recovery, decreased transfusion burden of platelets and red blood cells, and increased donor chimerism were observed. Decreases in myeloblasts and reduction in the size of an extramedullary myeloid sarcoma were suggestive of clinical activity. One patient, a 23-year- old with MRD+ disease at baseline, received two doses of 200M NEXI-001 cells separated by approximately 2 months. Following the first infusion, antigen specific CD8+ T cells increased gradually in PB to 9% of the total CD3+ T cell population just prior to the second infusion and were found to have trafficked to bone marrow. By Day 2 following the second infusion, which was not preceded by LD chemotherapy, the antigen specific CD8+ T cells again increased to 9% of the total CD3+ T cell population in PB and remained at ≥5% until the end of study visit a month later. The absolute lymphocyte count increased by 50% highlighting continued expansion of the NEXI-001 T cells. These cells also maintained significant Tscm populations. Treatment related adverse events, including infusion reactions, GVHD, CRS, and neurotoxicity (ICANS), have not developed in these patients who have received 50M to 200M T cells of the NEXI-001 product either as single or repeat infusions. In conclusion, these results show that infusion of the NEXI-001 product is safe and capable of generating a cell-mediated immune response with early signs of clinical activity. A second infusion is associated with increasing the level of antigen specific CD8+ T cells and their persistence in PB and BM. TCR sequencing and RNA Seq transcriptional profiling of the CD8+ T cells are planned, and these data will be available for presentation during the ASH conference. At least two cycles of 200M NEXI-001 cells weekly x 3 weeks of a 4-week cycle is planned for the next dose-escalation cohort. Early data suggest that the NEXI-001 product has the potential to enhance a GvL effect with minimal GVHD-associated toxicities. Disclosures Al Malki: Jazz Pharmaceuticals, Inc.: Consultancy; Neximmune: Consultancy; Hansa Biopharma: Consultancy; CareDx: Consultancy; Rigel Pharma: Consultancy. Vasu: Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: travel support; Kiadis, Inc.: Research Funding; Omeros, Inc.: Membership on an entity's Board of Directors or advisory committees. Modi: MorphoSys: Membership on an entity's Board of Directors or advisory committees; Seagen: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding. Perales: Sellas Life Sciences: Honoraria; Novartis: Honoraria, Other; Omeros: Honoraria; Merck: Honoraria; Takeda: Honoraria; Karyopharm: Honoraria; Incyte: Honoraria, Other; Equilium: Honoraria; MorphoSys: Honoraria; Kite/Gilead: Honoraria, Other; Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Medigene: Honoraria; NexImmune: Honoraria; Cidara: Honoraria; Nektar Therapeutics: Honoraria, Other; Servier: Honoraria; Miltenyi Biotec: Honoraria, Other. Edavana: Neximmune, Inc: Current Employment. Lu: Neximmune, Inc: Current Employment. Kim: Neximmune, Inc: Current Employment. Suarez: Neximmune, Inc: Current Employment. Oelke: Neximmune, Inc: Current Employment. Bednarik: Neximmune, Inc: Current Employment. Knight: Neximmune, Inc: Current Employment. Varela: Kite: Speakers Bureau; Nexlmmune: Current equity holder in publicly-traded company, Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Development and Evaluation of a Human Single Chain Variable Fragment (scFv) Derived Bcma Targeted CAR T Cell Vector Leads to a High Objective Response Rate in Patients with Advanced MM

Blood ◽

10.1182/blood.v130.suppl_1.742.742 ◽

2017 ◽

Vol 130 (Suppl_1) ◽

pp. 742-742 ◽

Cited By ~ 1

Author(s):

Eric L Smith ◽

Sham Mailankody ◽

Arnab Ghosh ◽

Reed Masakayan ◽

Mette Staehr ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Employment Equity ◽

Advisory Committees ◽

Car T Cells ◽

Car T Cell ◽

Car T ◽

Equity Ownership

Abstract Patients with relapsed/refractory MM (RRMM) rarely obtain durable remissions with available therapies. Clinical use of BCMA targeted CAR T cell therapy was first reported in 12/2015 for RRMM, and based on small numbers, preliminary results appear promising. Given that host immune anti-murine CAR responses have limited the efficacy of repeat dosing (Turtle C. Sci Trans Med 2016), our goal was to develop a human BCMA targeted CAR T cell vector for clinical translation. We screened a human B cell derived scFv phage display library containing 6x1010 scFvs with BCMA expressing NIH 3T3 cells, and validated results on human MM cell lines. 57 unique and diverse BCMA specific scFvs were identified containing light and heavy chain CDR's each covering 6 subfamilies, with HCDR3 length ranges from 5-18 amino acids. 17 scFvs met stringent specificity criteria, and a diverse set was cloned into CAR vectors with either a CD28 or a 4-1BB co-stimulatory domain. Donor T cells transduced with BCMA targeted CAR vectors that conveyed particularly desirable properties over multiple in vitro assays, including: cytotoxicity on human MM cell lines at low E:T ratios (>90% lysis, 1:1, 16h), robust proliferation after repeat antigen stimulation (up to 700 fold, stimulation q3-4d for 14d), and active cytokine profiling, were selected for in vivo studies using a marrow predominant human MM cell line model in NSG mice. A single IV injection of CAR T cells, either early (4d) or late (21d) after MM engraftment was evaluated. In both cases survival was increased when treated with BCMA targeted CAR T cells vs CD19 targeted CAR T cells (median OS at 60d NR vs 35d p<0.05). Tumor and CAR T cells were imaged in vivo by taking advantage of luciferase constructs with different substrates. Results show rapid tumor clearance, peak (>10,000 fold) CAR T expansion at day 6, followed by contraction of CAR T cells after MM clearance, confirming the efficacy of the anti-BCMA scFv/4-1BB containing construct. Co-culture with primary cells from a range of normal tissues did not activate CAR T cells as noted by a lack of IFN release. Co-culture of 293 cells expressing this scFv with those expressing a library of other TNFRSF or Ig receptor members demonstrated specific binding to BCMA. GLP toxicity studies in mice showed no unexpected adverse events. We generated a retroviral construct for clinical use including a truncated epithelial growth factor receptor (EGFRt) elimination gene: EGFRt/hBCMA-41BBz. Clinical investigation of this construct is underway in a dose escalation, single institution trial. Enrollment is completed on 2/4 planned dose levels (DL). On DL1 pts received cyclophosphamide conditioning (3g/m2 x1) and 72x106 mean CAR+ T cells. On DL2 pts received lower dose cyclophosphamide/fludarabine (300/30 mg/m2 x3) and 137x106 mean CAR+ T cells. All pts screened for BCMA expression by IHC were eligible. High risk cytogenetics were present in 4/6 pts. Median prior lines of therapy was 7; all pts had IMiD, PI, high dose melphalan, and CD38 directed therapies. With a data cut off of 7/20/17, 6 pts are evaluable for safety. There were no DLT's. At DL1, grade 1 CRS, not requiring intervention, occurred in 1/3 pts. At DL2, grade 1/2 CRS occurred in 2/3 pts; both received IL6R directed Tocilizumab (Toci) with near immediate resolution. In these 2 pts time to onset of fever was a mean 2d, Tmax was 39.4-41.1 C, peak CRP was 25-27mg/dl, peak IL6 level pre and post Toci were 558-632 and 3375-9071 pg/ml, respectively. Additional serum cytokines increased >10 fold from baseline in both pts include: IFNg, GM CSF, Fractalkine, IL5, IL8, and IP10. Increases in ferritin were limited, and there were no cases of hypofibrinogenemia. There were no grade 3-5 CRS and no neurotoxicities or cerebral edema. No pts received steroids or Cetuximab. Median time to count recovery after neutropenia was 10d (range 6-15d). Objective responses by IMWG criteria after a single dose of CAR T cells were observed across both DLs. At DL1, of 3 pts, responses were 1 VGPR, 1 SD, and 1 pt treated with baseline Mspike 0.46, thus not evaluable by IMWG criteria, had >50% reduction in Mspike, and normalization of K/L ratio. At DL2, 2/2 pts had objective responses with 1 PR and 1 VGPR (baseline 95% marrow involvement); 1 pt is too early to evaluate. As we are employing a human CAR, the study was designed to allow for an optional second dose in pts that do not reach CR. We have treated 2 pts with a second dose, and longer follow up data is pending. Figure 1 Figure 1. Disclosures Smith: Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: BCMA targeted CAR T cells, Research Funding. Almo: Cue Biopharma: Other: Founder, head of SABequity holder; Institute for Protein Innovation: Consultancy; AKIN GUMP STRAUSS HAUER & FELD LLP: Consultancy. Wang: Eureka Therapeutics Inc.: Employment, Equity Ownership. Xu: Eureka Therapeutics, Inc: Employment, Equity Ownership. Park: Amgen: Consultancy. Curran: Juno Therapeutics: Research Funding; Novartis: Consultancy. Dogan: Celgene: Consultancy; Peer Review Institute: Consultancy; Roche Pharmaceuticals: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Liu: Eureka Therpeutics Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Brentjens: Juno Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

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Adoptive T-Cell Therapy for Acute Lymphoblastic Leukemia Targeting Multiple Tumor Associated Antigens

Blood ◽

10.1182/blood-2018-99-115465 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2693-2693

Author(s):

Swati Naik ◽

Premal Lulla ◽

Ifigeneia Tzannou ◽

Robert A. Krance ◽

George Carrum ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Disease Relapse ◽

Advisory Committees ◽

Leukemic Relapse ◽

Post Infusion ◽

Equity Ownership ◽

T Cell Lines

Abstract Background: Leukemic relapse remains the major cause of treatment failure in hematopoietic stem cell transplant (HSCT) recipients. While the infusion of donor lymphocytes to prevent and treat relapse has been clinically implemented this strategy does not provide durable remissions and carries the risk of life-threatening graft-versus-host disease (GVHD). More recently the adoptive transfer of T cells that have been engineered to express CD19-targeted chimeric antigen receptors (CARs), has shown potent anti-leukemic activity in HSCT recipients with recurrent disease. However, disease relapse with the emergence of CD19 negative tumors is an emerging clinical issue post-administration of these mono-targeted T cells. To overcome these limitations, we developed a protocol for the generation of donor-derived T cell lines that simultaneously targeted a range of tumor associated antigens (multiTAAs) that are frequently expressed by B- and T-cell ALL including PRAME, WT1 and Survivin for adoptive transfer to high risk recipients transplanted for ALL. Methods/Results: We were consistently able to generate donor-derived multiTAA-specific T cells by culturing PBMCs in the presence of a Th1-polarizing/pro-proliferative cytokine cocktail, using autologous DCs as APCs and loading them with pepmixes (15 mer peptides overlapping by 11 amino acids) spanning all 3 target antigens. The use of whole antigen increases the range of patient HLA polymorphisms that can be exploited beyond those matched to single peptides, while targeting multiple antigens simultaneously reduces the risk of tumor immune evasion. To date, we have generated 14 clinical grade multiTAA-specific T cell lines comprising CD3+ T cells (mean 94±9%) with a mixture of CD4+ (mean 21±28%) and CD8+ (mean 52±24 %) cells, which expressed central [CD45RO+/CD62L+: 14±9%] and effector memory markers [CD45RO+/CD62L-: 80±11%] associated with long term in vivo persistence. The expanded lines recognized the targeted antigens WT1, PRAME and Survivin by IFNg ELIspot with activity against >1 targeted antigens in all cases. None of the lines reacted against non-malignant patient-derived cells (4±3% specific lysis; E: T 20:1) - a study release criterion. Thus far we have treated 8 high risk ALL patients with donor derived TAA T cells post-transplant to prevent disease relapse (Table 1). Infusions were well tolerated with no dose-limiting toxicity, GVHD, CRS or other adverse events. Two patients were not evaluable per study criteria as they received >0.5mg/kg of steroids within 4 weeks of infusion and were replaced. Five of the 6 remaining patients infused remain in CR a median of 11.2 months post-infusion (range 9-22 months). We detected the expansion of tumor-reactive T cells in patient peripheral blood post-infusion against both targeted (WT1, Survivin, PRAME) and non-targeted antigens (SSX2, MAGE-A4, -A1, -A2B, -C1, MART1, AFP and NYESO1) reflecting epitope and antigen spreading. The single patient who relapsed showed no evidence of tumor-directed T cell expansion despite receiving 3 additional infusions at 4 week intervals. Conclusion: In summary, infusion of donor multi-TAA-specific T cells to patients with ALL post allogeneic HSCT is feasible, safe and as evidenced by expansion and antigen spreading in patients, may contribute to disease control. This strategy may present a promising addition to current immunotherapeutic approaches for prophylaxis for leukemic relapse in HSCT recipients. Table 1. Table 1. Disclosures Vera: Marker: Equity Ownership. Heslop:Marker: Equity Ownership; Cytosen: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Research Funding; Gilead Biosciences: Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Research Funding; Viracyte: Equity Ownership. Leen:Marker: Equity Ownership.

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The Innate Immune Sensor Sting Promotes Donor CD8+ T Cell Activation and Recipient APC Death Early after Preclinical Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2019-130197 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3202-3202

Author(s):

Cameron S. Bader ◽

Henry Barreras ◽

Casey O. Lightbourn ◽

Sabrina N. Copsel ◽

Dietlinde Wolf ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

T Cell Activation ◽

Cd8 T Cells ◽

Research Funding ◽

Cell Activation ◽

Cd8 T Cell ◽

Advisory Committees ◽

Hematopoietic Stem

Graft-versus-host disease (GVHD) remains a significant cause of morbidity and mortality in patients receiving allogeneic hematopoietic stem cell transplants (aHSCTs). Pre-HSCT conditioning typically consists of irradiation and drug administration resulting in the death of rapidly dividing cells and release of endogenous danger signals. These molecules drive the activation of antigen presenting cells (APCs) and the differentiation of allo-reactive donor T cells, leading to damage of particular host tissues characteristic of GVHD. Cell death following conditioning has promoted the hypothesis that sensors of cytoplasmic DNA damage in GVHD target tissues contribute to pro-inflammatory cytokine production. We identified a role for Stimulator of Interferon Genes (STING), an innate immune sensor, in GVHD using pre-clinical MHC-matched unrelated donor (MUD) aHSCT models. Here we show that STING rapidly promotes donor CD8+ T cell activation and recipient APC death early after aHSCT. To assess STING involvement immediately post-HSCT, cytokine mRNA expression was examined 48 hrs after transplant of MUD C3H.SW bone marrow (BM) + T cells into irradiated B6 wildtype (WT) or STING-/- recipients. Colon tissue from STING-/- recipients had >2x reduction in IFNβ, TNFα and IL-6 mRNA vs WT. MUD STING-/- HSCT recipients also experienced decreased weight loss, GVHD scores and skin pathology 6 wks post-HSCT vs WT. Double chimerism studies showed that the absence of STING in non-hematopoietic cells was responsible for GVHD amelioration. Conversely, a single dose of the highly specific STING agonist DMXAA given in vivo increased IFNβ, TNFα and IL-6 mRNA expression in WT, but not STING-/-, colon tissue 48 hrs after transplant and increased GVHD scores and lethality post-HSCT. Post-transplant cytoxan treatment abolished the ability of DMXAA to augment GVHD, supporting the notion that STING signaling increases donor T cell activation during aHSCT. To evaluate the potential impact of STING in the clinical setting, we transplanted C3H.SW BM + T cells into mice homozygous for a murine homologue of a human allele associated with diminished STING activity (STINGHAQ/HAQ) and found that these mice also exhibited diminished GVHD. Interestingly, our findings that STING deficiency ameliorates GVHD in MUD aHSCT contrasts to reported observations that STING deficiency can exacerbate GVHD after MHC-mismatched (MMUD) aHSCT (Fischer J, et al, Sci. Transl. Med. 2017). Since CD4+ and CD8+ T cells are central in MMUD and MUD GVHD, respectively, we hypothesized that STING's effect on the predominant T cell subset in each model may explain these seemingly paradoxical results in STING-/- vs WT recipients. Therefore, we transplanted MMUD BALB/c BM + CD8+ T cells into B6-WT and STING-/- mice and found that - in contrast to MMUD recipients of combined CD4+ and CD8+ T cells - STING-/- recipients developed lower GVHD clinical scores, reduced skin pathology and had lower frequencies of activated T cells 8 wks post-HSCT vs WT, supporting a role for STING in the promotion of CD8+ T cell-mediated GVHD. Next, we investigated if recipient APCs played a role in STING's enhancement of CD8+ T cell-mediatedGVHD. We found that STING-/- mice had greater frequencies and numbers of recipient splenic CD11b+CD11c+ APCs 1 day after MMUD B6 into BALB/c aHSCT (Fig. A). BALB/c-STING-/- APCs also expressed reduced MHC class I protein levels (Fig. B). Moreover, STING-/- recipient spleens contained lower numbers of donor CD8+ T cells producing IFNγ and TNFα (Fig. C). These data support the hypothesis that STING contributes to early activation of donor CD8+ T cells and elimination of recipient APCs. Next, to identify if the loss of host MHC II+ APCs affected subsequent donor CD4+ T cell activation, B6-Nur77GFP transgenic donor T cells were used to explicitly monitor T cell receptor signaling. Consistent with increased numbers of host MHC II+ APCs in the spleens of STING-/- recipients 1 day post-aHSCT, we found greater frequencies and numbers of donor Nur77GFP CD4+ T cells expressing GFP, CD69 and IFNγ in STING-/- spleens 6 days after transplant (Fig. D). In summary, our studies demonstrate that STING plays an important role in regulating aHSCT and provide one potential mechanism by which STING could promote CD8+ T cell-mediated GVHD yet diminish CD4+-mediated GVHD. Overall, our studies suggest this pathway can provide a target for new therapeutic strategies to ameliorate GVHD. Disclosures Blazar: BlueRock Therapeutics: Membership on an entity's Board of Directors or advisory committees; Childrens' Cancer Research Fund: Research Funding; KidsFirst Fund: Research Funding; Tmunity: Other: Co-Founder; Kamon Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Regeneron Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Five Prime Therapeutics Inc: Co-Founder, Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics and BlueRock Therapeuetics: Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics, Inc.: Research Funding; RXi Pharmaceuticals: Research Funding; Alpine Immune Sciences, Inc.: Research Funding; Abbvie Inc: Research Funding; Leukemia and Lymphoma Society: Research Funding. Levy:Heat Biologics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pelican Therapeutics: Consultancy, Research Funding.

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