scholarly journals Therapeutic Targeting of Mertk and BCL-2 in T-Cell and Early T-Precursor Acute Lymphoblastic Leukemia

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1184-1184
Author(s):  
Ryan J Summers ◽  
Juhi Jain ◽  
Eleana Vasileiadi ◽  
Brittany Smith ◽  
Madison Stout ◽  
...  
Keyword(s):  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Lymphoblastic Leukemia ◽  
Xenograft Model ◽  
Prolonged Survival ◽  
Cell Phenotype ◽  
Advisory Committees ◽  
Equity Ownership

Abstract Introduction T-cell acute lymphoblastic leukemia (T-ALL) accounts for 15% of childhood ALL and is associated with inferior outcomes relative to B-cell ALL. Early T-precursor ALL (ETP-ALL) is a subset of T-ALL characterized by an immature T cell phenotype, resistance to therapy, and high rates of induction failure. MERTK receptor tyrosine kinase is ectopically expressed in 40-50% of T-ALLs, particularly those with an immature T cell phenotype, suggesting a role in ETP-ALL. Inhibition of MERTK using shRNA delayed leukemia progression and prolonged survival in a T-ALL xenograft model, implicating MERTK as a therapeutic target. MRX-2843 is an orally available dual MERTK/FLT3 inhibitor currently in phase I clinical trials. The anti-apoptotic protein B-cell lymphoma-2 (BCL-2) is specifically expressed in immature T cell precursors, is preferentially expressed in ETP-ALL compared to other T-ALLs, is essential for ETP-ALL cell survival, and is regulated downstream of MERTK in acute leukemia cells. Thus, combination therapies targeting these two proteins may be particularly effective to treat ETP-ALL. Methods Loucy and PEER ETP-ALL cell lines were cultured with vehicle or MRX-2843. Phosphorylated and total MERTK were assessed by immunoblot. Relative cell numbers were measured using Presto Blue reagent. Cells were stained with PoPro-1-iodide and propidium iodide and apoptotic and dead cells were quantitated by flow cytometry. T-ALL patient samples were cultured with UNC2025, a close analogue of MRX-2843, and relative cell numbers were assessed using MTS reagent. Orthotopic xenografts were established in NSG or NSGS mice using luciferase-expressing Jurkat cells (T-ALL), luciferase-expressing Loucy cells (ETP-ALL) or an ETP-ALL patient sample and leukemia burden was monitored by bioluminescence imaging or flow cytometry. MRX-2843 (65 mg/kg or 75 mg/kg) or saline vehicle were administered orally once daily. Differences in disease burden were assessed with the Mann-Whitney-U test or one-way ANOVA. Survival was determined by Kaplan-Meier analysis. Loucy and PEER cells were plated and screened in quadruplicate against >150 pairwise combinations of MRX-2843 and the BCL-2 inhibitor venetoclax in a high-throughput format. Synergy was calculated using the response additivity model. Results Treatment with MRX-2843 mediated a dose-dependent decrease in phosphorylated MERTK, inhibited expansion of ETP-ALL cells, and induced cell death in vitro. Fifty-four percent (21/39) of primary T-ALL patient samples were sensitive to UNC2025 with an IC 50≤550 nM, including 2/5 (40%) pediatric samples and 10/19 (53%) adolescent/young adult samples. Treatment with MRX-2843 significantly reduced leukemia burden in cell line-derived T-ALL and ETP-ALL xenograft models and prolonged survival by 50% and 13% in the T-ALL (n=10, p<0.0001) and ETP-ALL (n=10, p=0.0136) models, respectively. Similarly, in a patient-derived ETP-ALL xenograft model, treatment with MRX-2843 reduced peripheral blood disease burden by 83% and spleen weight by 64% compared to vehicle-treated mice (n=8, p<0.001) and prolonged survival by 41% (n=8, p=0.0016). MRX-2843 mediated anti-leukemia activity in combination with venetoclax and a dose ratio of 1:20 MRX-2843:venetoclax provided optimal synergy in Loucy and PEER ETP-ALL cells in vitro (Figure 1). Conclusions MRX-2843 has therapeutic activity in ETP-ALL cell culture and xenograft models and over half of T-ALL patient samples were sensitive to MERTK/FLT3 inhibition. MRX-2843 also mediated synergistic anti-leukemia activity against ETP-ALL cells in combination with venetoclax, with an optimal molar ratio of 1:20. These data demonstrate the therapeutic potential of MRX-2843 in patients with T-ALL, suggest that MRX-2843 may be particularly active alone and in combination with venetoclax in the ETP-ALL subset, and provide rationale for clinical testing of MRX-2843, with the ultimate goal to progress to trials evaluating MRX-2843 in combination with other agents. Toward this end, MRX-2843 monotherapy will be tested in patients with relapsed leukemia in an upcoming clinical trial (NCT04872478). Figure 1 Figure 1. Disclosures Wang: Meryx: Other: Equity ownership; University of North Carolina: Patents & Royalties. Frye: University of North Carolina: Patents & Royalties; Meryx: Membership on an entity's Board of Directors or advisory committees, Other: Equity ownership. Earp: Meryx: Membership on an entity's Board of Directors or advisory committees, Other: Equity ownership. Tyner: Petra: Research Funding; Incyte: Research Funding; Takeda: Research Funding; Janssen: Research Funding; Astrazeneca: Research Funding; Array: Research Funding; Constellation: Research Funding; Seattle Genetics: Research Funding; Schrodinger: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Agios: Research Funding. DeRyckere: Meryx: Other: Equity ownership. Graham: Meryx: Membership on an entity's Board of Directors or advisory committees, Other: Equity ownership.

scholarly journals T-Cell Suppression By Src/ABL Kinase Inhibitors When Combined with Blinatumomab in Ph+ Acute Lymphoblastic Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2694-2694 ◽  
Author(s):  
Jessica Leonard ◽  
Yoko Kosaka ◽  
Pavani Malla ◽  
Brandon Hayes-Lattin ◽  
Adam J. Lamble ◽  
...  
Keyword(s):  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Kinase Inhibitors ◽  
Cell Function ◽  
Lymphoblastic Leukemia ◽  
Advisory Committees ◽  
Abl Kinase ◽  
Equity Ownership ◽  
Abl Kinase Inhibitors

Abstract Introduction: Targeted ABL kinase inhibitors (TKIs) have shown great activity in Ph+ Acute Lymphoblastic Leukemia (Ph+ ALL), however relapsed disease remains an unmet need. The bispecific antibody blinatumomab was recently approved as a single agent for use in patients with Ph+ ALL and there is much interest in combining this with targeted therapies. Second generation ABL kinase inhibitors inhibit both Src and LYN in addition to ABL. This is of particular interest in Ph+ ALL as LYN is important for leukemogenesis. T cell receptor (TCR) signaling is also dependent upon Src family kinase activity, and Src inhibitors may impact the efficacy of immunotherapies reliant on native T cell function. We sought to investigate the in vitro effects of ABL specific vs dual Src/ABL kinases on blinatumomab efficacy in both healthy donor as well as primary patient samples. Methods: We isolated peripheral blood mononuclear cells (PBMC) via Ficoll-Hypaque gradient from five healthy donors as well as from two patients with de novo and one patient with relapsed Ph+ ALL who harbored a T315I mutation. PBMC were labeled with CellTrace Violet and cultured for 5 days with no stimulation, blinatumomab, or blinatumomab in combination with imatinib, dasatinib, ponatinib or nilotinib at varying concentrations. Immunophenotyping was performed using multi-parameter flow cytometry for the following cell surface markers: CD45, CD3, CD4, CD8, CD56, and CD19. Blinatumomab efficacy was assessed by comparing the numbers of CD19+ / CD3- cells in untreated samples to those that had been treated with blinatumomab in the presence or absence of TKIs. Cell division of T cells was measured by CellTrace Violet dilution. Cytokine production was assessed via LEGENDplex Human Th Cytokine Panel. Levels of total Src, phospho-Src, total LCK and phospho-LCK were assessed via immunoblot. Results: After 5 days of exposure, blinatumomab led to T-cell proliferation in both healthy donor and patient PBMCs. Proliferation was observed in both CD8+ and CD4+ T cell subsets, although the effect was more pronounced in CD8+ cells. T cell proliferation, however, was completely suppressed by either dasatinib or ponatinib at nanomolar concentrations. This effect was far less pronounced with the ABL kinase inhibitors imatinib and nilotinib. Treatment of PBMCs with blinatumomab led to increased production of the cytokines IFN-g, IL-17-a and IL-22 in patient samples and healthy donors, while levels of IL-6 were increased in the patient samples only and levels of IL-10 in healthy subjects only. Cytokine production was absent in samples treated with blinatumomab and either dasatinib or ponatinib, while levels of IFN-g, IL-17a and IL-22 were minimally affected when blinatumomab was combined with imatinib. Immunoblots confirmed that dasatinib and ponatinib but not imatinib nor nilotinib inhibited phosphorylation of total Src as well as of LCK, likely explaining the inhibitory effects of these agents. In patient samples, blinatumomab alone and the TKIs alone greatly reduced the number of CD19+ cells. However, when dasatinib and blinatumomab were combined in the sample with a T315I mutation, there was little reduction in the percentage of CD19+ cells and no amplification of CD3+ cells, suggesting that dasatinib was able to inhibit the cytotoxic effects of blinatumomab with no effect to the leukemic cells. Discussion: Our results suggest that the combination of dual Src/ABL inhibitors with blinatumomab may abrogate the effects of blinatumomab by directly inhibiting T cell function. This is likely via inhibition of LCK, a known member of the TCR signaling pathway. Although small case series have reported responses in patients treated with blinatumomab and TKIs, it is possible that the majority of the response is from the TKI rather than blinatumomab. Only a randomized trial of a TKI +/- blinatumomab would be able to discern whether there is benefit of adding a dual Src/ABL TKI to bispecific antibody therapy. While our data are limited by sample numbers and by the fact that responses in living subjects may differ according to many other complex interactions in the in vivo immune microenvironment, the potential immunomodulatory effects of targeted therapies should be taken into consideration before they are combined with immunotherapies. Disclosures Leonard: Amgen: Research Funding. Druker:McGraw Hill: Patents & Royalties; Fred Hutchinson Cancer Research Center: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; ARIAD: Research Funding; Monojul: Consultancy; Millipore: Patents & Royalties; Novartis Pharmaceuticals: Research Funding; Oregon Health & Science University: Patents & Royalties; Leukemia & Lymphoma Society: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Meyers Squibb: Research Funding; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Beta Cat: Membership on an entity's Board of Directors or advisory committees; MolecularMD: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Patient True Talk: Consultancy; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; GRAIL: Consultancy, Membership on an entity's Board of Directors or advisory committees; Aileron Therapeutics: Consultancy; Henry Stewart Talks: Patents & Royalties; Aptose Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Tyner:Constellation: Research Funding; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Gilead: Research Funding; Aptose: Research Funding; Incyte: Research Funding; Genentech: Research Funding; Array: Research Funding; Takeda: Research Funding; AstraZeneca: Research Funding. Lind:Celgene: Research Funding; Janssen Pharmaceutical R&D: Research Funding; Amgen: Research Funding; Fluidigm: Honoraria; Monojul: Research Funding.

scholarly journals GM-CSF Blockade during Chimeric Antigen Receptor T Cell Therapy Reduces Cytokine Release Syndrome and Neurotoxicity and May Enhance Their Effector Functions

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 961-961 ◽  
Author(s):  
Rosalie M. Sterner ◽  
Reona Sakemura ◽  
Nan Yang ◽  
Michelle J. Cox ◽  
Roman H. Khadka ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Therapy ◽  
Board Of Directors ◽  
Research Funding ◽  
Xenograft Model ◽  
Advisory Committees ◽  
T Cell Therapy ◽  
Effector Functions ◽  
Gm Csf

Abstract Despite its efficacy, chimeric antigen receptor T-cell therapy (CART) is limited by the development of cytokine release syndrome (CRS) and neurotoxicity (NT). While CRS is related to extreme elevation of cytokines and massive T cell expansion, the exact mechanisms for NT have not yet been elucidated. Preliminary studies suggest that NT might be mediated by myeloid cells that cross the blood brain barrier. This is supported by correlative analysis from CART19 pivotal trials where CD14+ cell numbers were increased in the cerebrospinal fluid of patients that developed severe NT (Locke et al, ASH 2017). Therefore, we aimed to investigate the role of GM-CSF neutralization in preventing CRS and NT after CART cell therapy via monocyte control. First, we investigated the effect of GM-CSF blockade on CART cell effector functions. Here, we used the human GM-CSF neutralizing antibody (lenzilumab, Humanigen, Burlingame, California) that has been shown to be safe in phase II clinical trials. Lenzilumab (10 ug/kg) neutralizes GM-CSF when CART19 cells are stimulated with the CD19+ Luciferase+ acute lymphoblastic leukemia (ALL) cell line NALM6, but does not impair CART cell function in vitro. We have found that malignancy associated macrophages reduce CART proliferation. GM-CSF neutralization with lenzilumab results in enhanced CART cell antigen specific proliferation in the presence of monocytes. To confirm this in vivo, NOD-SCID-g-/- mice were engrafted with high disease burdens of NALM6 and treated with low doses of CART19 or control T cells (to induce tumor relapse), in combination with lenzilumab or isotype control antibody. The combination of CART19 and lenzilumab resulted in significant anti-tumor activity and overall survival benefit compared to control T cells (Fig 1A), similar to mice treated with CART19 combined with isotype control antibody, indicating that GM-CSF neutralization does not impair CART cell activity in vivo. This anti-tumor activity was validated in an ALL patient derived xenograft model. Next, we explored the impact of GM-CSF neutralization on CART cell related toxicities in a novel patient derived xenograft model. Here, NOD-SCID-g-/- mice were engrafted with leukemic blasts (1-3x106 cells) derived from patients with high risk ALL. Mice were then treated with high doses of CART19 cells (2-5x106 intravenously). Five days after CART19 treatment, mice began to develop progressive motor weakness, hunched bodies, and weight loss that correlated with massive elevation of circulating human cytokine levels. Magnetic Resonance Imaging (MRI) of the brain during this syndrome showed diffuse enhancement and edema, associated with central nervous system (CNS) infiltration of CART cells and murine activated myeloid cells. This is similar to what has been reported in CART19 clinical trials in patients with severe NT. The combination of CART19, lenzilumab (to neutralize human GM-CSF) and murine GM-CSF blocking antibody (to neutralize mouse GM-CSF) resulted in prevention of weight loss (Fig 1B), decrease in critical myeloid cytokines (Fig 1C-D), reduction of cerebral edema (Fig 1E), enhanced leukemic disease control in the brain (Fig 1F), and reduction in brain macrophages (Fig 1G). Finally, we hypothesized that disrupting GM-CSF through CRISPR/Cas9 gene editing during the process of CART cell manufacturing would result in functional CART cells with reduced secretion of GM-CSF. We designed guide RNA targeting exon 3 of the GM-CSF gene and generated GM-CSFk/o CART19 cells. Our preliminary data suggest that these CARTs produce significantly less GM-CSF upon activation but continue to exhibit similar production of other cytokines and exhibit normal effector functions in vitro (Fig 1H). Using the NALM6 high tumor burden relapse xenograft model as described above, GM-CSFk/o CART19 cells resulted in slightly enhanced disease control compared to CART19 cells (Fig 1I). Thus, modulating myeloid cell behavior through GM-CSF blockade can help control CART mediated toxicities and may reduce their immunosuppressive features to improve leukemic control. These studies illuminate a novel approach to abrogate NT and CRS through GM-CSF neutralization that also potentially enhances CART cell functions. Based on these results, we have designed a phase II clinical trial using lenzilumab as a modality to prevent CART related toxicities in patients with diffuse large B cell lymphoma. Disclosures Ahmed: Humanigen: Employment. Sahmoud:Humanigen: Employment. Durrant:Humanigen: Employment. Russell:Vyriad: Equity Ownership. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding. Kenderian:Novartis: Patents & Royalties; Tolero Pharmaceuticals: Research Funding; Humanigen: Research Funding.

scholarly journals 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 ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1974-1974 ◽  
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.

scholarly journals Transgenic Expression of IL15 in CD123-Specific BiTE-Secreting Engager T-Cells Results in Improved Anti-AML Activity

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3917-3917
Author(s):  
Hong Mu-Mosley ◽  
Lauren B Ostermann ◽  
Muharrem Muftuoglu ◽  
Wendy Schober ◽  
Nalini B Patel ◽  
...  
Keyword(s):  
Gene Therapy ◽  
T Cells ◽  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Cell Group ◽  
Advisory Committees ◽  
Transgenic Expression ◽  
Equity Ownership

Background: CD123 is frequently expressed on hematologic malignancies including 96-98% of AML. CD123 has been a potential immunotherapeutic target in AML due to its association with leukemic stem cells that play an essential role in disease progression and relapse. Our previous study using T-cells secreting CD123/CD3-bispecific T-cell engagers (BiTEs) (CD123-ENG T-cells) showed a promising approach anti-AML activity, however T-cell persistence was limited. Interleukin-15 (IL15) has emerged as a candidate immunomodulator as it enhances T-cell expansion and persistence, and induces long-lasting memory T-cells. To improve the efficacy and persistence of CD123-ENG T-cells we developed IL15 expressing CD123-ENG T-cells. Here, we report on the characterization and efficacy of IL15-secreting CD123-ENG T cells in vitro and in vivo models of adult AML. Methods/Results: A cDNA encoding IL15 was cloned into retroviral vectors encoding CD123-ENG or CD19-ENG (CD123-ENG.IL15; CD19-ENG.IL15). ENG T-cells were generated from human peripheral blood mononuclear cells (PBMCs) from normal donors or T-cells from AML patients by retroviral transduction and in vitro expansion. Non-transduced (NT) T-cells and T-cells expressing CD123 (CD123-ENG T-cells) served as controls. IL15 production of CD19-ENG.IL15 and CD123-ENG.IL15 T cells was confirmed by ELISA (144-159 pg/ml vs 38 and 46 pg/ml of NT and CD123-ENG T cells, p<0.01, n=6). Both CD123-ENG and CD123-ENG.IL15 T-cells recognized CD123+ AML cells as judged by IL2 and interferon γ (IFNγ) production (p<0.01, n=5). In contrast, NT and CD19-ENG.IL15 T-cells did not, confirming specificity. In addition, CD123-ENG.IL15 and CD123-ENG T-cells induced killing of only CD123-positive target cells as well as of primary adult patients' AML blasts in luciferase- or 7AAD-based cytotoxicity assays (p<0.001, n=10). CD123-ENG.IL15 T-cells showed greater cytolytic activity than CD123-ENG T-cells as determined by luciferase activity (p=0.0002, n=3). In a Molm13 AML xenograft model, CD123-ENG.IL15 and CD123-ENG T-cells exhibited potent anti-leukemic activity as judged by bioluminescence imaging. Moreover, CD123-ENG.IL15 T cells had enhanced anti-leukemic activity and greater persistence in BMs, spleens, and livers in comparison to CD123-ENG T cells, resulting in improved anti-AML activity (Figure 1, p<0.01 vs CD123-ENG T-cell group, n=12 per group) and extended survival (Figure 2, p=0.0097 vs CD123-ENG T-cell group). Finally, AML PDX models and ENG T-cells were generated from AML blasts and T-cells from 3 patients with active AML. Infusion of autologous ENG T-cells (1.5x106 cells/mouse, n=7) in AML PDX#6697688 mouse model revealed significant reduction of leukemia burden in the CD123-ENG.IL15 or CD123-ENG T-cells mouse groups but not in the mouse group with NT or CD19-ENG.IL15 T-cells or PBS (p=0.004, n=6-8). We are currently monitoring survival of these PDX models. Conclusion: We here demonstrated that transgenic expression of IL15 in CD123-ENG T-cells results in improved expansion and persistence, and anti-AML activity. These results warrant further exploration of IL15-modified CD123-targeted T-cells as immunotherapy for AML. Disclosures Bonifant: Patents filed in the field of engineered cellular therapies: Patents & Royalties: Patents filed in the field of engineered cellular therapies. Gottschalk:EMD Serono: Honoraria; Inmatics: Membership on an entity's Board of Directors or advisory committees; ASSISI fundation of Memphis: Research Funding; TESSA Therapeutics: Other: Research Collaboration; ViraCyte: Consultancy; NHLBI: Research Funding; America Lebanese Syrian Associated Charities: Research Funding; California Institute for Regenerative Medicine: Research Funding; Patents and patent applications in the fields of T-cell & Gene therapy for cancer: Patents & Royalties; MBIO: Other: St. Jude Children's Research Hospital has an existing exclusive license and ongoing partnership with Mustang Bio for the further clinical development and commercialization of this XSCID gene therapy; Sanofi: Honoraria; Tidal: Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy. Velasquez:St. Jude: Patents & Royalties: Patent Applications in the Fields of Cell and Gene Therapy ; Rally! Foundation: Membership on an entity's Board of Directors or advisory committees. Andreeff:Senti Bio: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; AstaZeneca: Consultancy; Amgen: Consultancy; Eutropics: Equity Ownership; Aptose: Equity Ownership; Reata: Equity Ownership; 6 Dimensions Capital: Consultancy; Celgene: Consultancy; Jazz Pharmaceuticals: Consultancy; Daiichi Sankyo, Inc.: Consultancy, Patents & Royalties: Patents licensed, royalty bearing, Research Funding; Cancer UK: Membership on an entity's Board of Directors or advisory committees; NCI-CTEP: Membership on an entity's Board of Directors or advisory committees; German Research Council: Membership on an entity's Board of Directors or advisory committees; Leukemia Lymphoma Society: Membership on an entity's Board of Directors or advisory committees; NCI-RDCRN (Rare Disease Cliln Network): Membership on an entity's Board of Directors or advisory committees; CLL Foundation: Membership on an entity's Board of Directors or advisory committees; BiolineRx: Membership on an entity's Board of Directors or advisory committees; NIH/NCI: Research Funding; Center for Drug Research & Development: Membership on an entity's Board of Directors or advisory committees; CPRIT: Research Funding; Oncoceutics: Equity Ownership; Oncolyze: Equity Ownership; Breast Cancer Research Foundation: Research Funding.

scholarly journals IL15 Expressing CD123-Targeted Engager T-Cell Therapy for Adult Acute Myeloid Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2724-2724 ◽  
Author(s):  
Hong Mu ◽  
Huaxian Ma ◽  
Abishek Vaidya ◽  
Challice L. Bonifant ◽  
Stephen Gottschalk ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Board Of Directors ◽  
Research Funding ◽  
Cytolytic Activity ◽  
Advisory Committees ◽  
T Cell Therapy ◽  
Equity Ownership

Abstract Background: CD123 is a potential immunotherapeutic target in AML due to its overexpression on leukemic stem cells that play an essential role in disease progression and relapse. Our previous study using T cells secreting CD123/CD3 bispecific engager molecules (CD123-ENG T cells) showed promising results in pediatric AML. Interleukin-15 (IL15) has emerged as a candidate immunomodulator as it enhances the cytolytic activity of CD8+ T-cells and induces long-lasting memory T cells. To improve the efficacy and persistence of CD123-ENG T-cells we developed IL-15 expressing CD123-ENG T cells. Here, we report characterization and efficacy of IL15 secreting CD123-ENG T cells in adult AML. Methods/Results: A cDNA encoding IL15 was cloned into retroviral vectors encoding CD123-ENG or CD19-ENG and the CD20 suicide gene separated by 2A sequences (CD20.2A.CD123-ENG.2A.IL15; CD20.2A.CD19-ENG.2A.IL15). ENG T cells were generated from human peripheral blood mononuclear cells (PBMCs) from normal donors by retroviral transduction and expanded in vitro. Non-transduced (NT) T cells and T cells expressing CD20 and CD123 (CD20.CD123-ENG T cells) served as controls. The transduction efficiency was between 62.81-95% (average 72%, n=3) and phenotypic analysis by flow cytometry showed reproducible CD4+, CD8+, central memory (CCR7+CD45RA-), effector memory (CCR7-CD45RA-), and naïve (CCR7+CD45RA+) T cells populations compared to NT cells. IL15 production of CD20.CD19-ENG.IL15 and CD20.CD123-ENG.IL15 T cells was confirmed by ELISA (84-154 pg/ml vs 32 and 44 pg/ml of NT and CD20.CD123-ENG T cells, p<0.01, n=3). Both, CD20.CD123-ENG and CD20.CD123-ENG.IL15 T cells recognized CD123+ AML cell lines as determined by IL2 and interferon γ (IFNγ) production (p<0.01, n=3). In contrast, NT and CD20.CD19-ENG.IL15 T cells did not, confirming specificity. In addition, CD20.CD123-ENG and CD20.CD123-ENG.IL15 T cells induced killing of only CD123-positive target cells in luciferase-and 7AAD-based cytotoxicity assay. CD20.CD123-ENG.IL15 T cells showed greater cytolytic activity than CD20.CD123-ENG T cells (p=0.0002, n=3). Finally, we evaluated the cytolytic activity of ENG T cells against two CD123+ adult AML PDX samples with clinically high-risk features (PDX#440778 [Flt3-ITD and D835 double mutations], and PDX#LFS [p53 mutant Li Fraumeni syndrome]). Both, CD20.CD123-ENG and CD20.CD123-ENG.IL15 T cells significantly killed AML PDX cells compared to NT and CD20.CD19-ENG.IL15 T cells (p<0.001, n=3). Adoptive transfer of CD20.CD123-ENG or CD20.CD123-ENG.IL15 T cells into the AML PDX#440778 mouse model revealed a significant reduction of leukemia burden in mice that received CD20.CD123-ENG.IL15 T cells 5 days post infusion (p=0.004, n=7). We are currently monitoring AML burden, frequency of infused ENG T cells, body weight and survival of treated mice, and conducting experiments in the 2nd AML PDX model. These results will be presented at the meeting. Conclusion: We demonstrate here that genetically engineering CD123-ENG T cells that express IL15 enhances their effector function resulting in improved anti-AML activity in in vitro and in vivo. The results warrant further exploration of IL15 secreting CD123-specific ENG T-cell therapy in AML. Disclosures Andreeff: Celgene: Consultancy; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; SentiBio: Equity Ownership; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; Jazz Pharma: Consultancy; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Reata: Equity Ownership; Astra Zeneca: Research Funding; Oncolyze: Equity Ownership; Amgen: Consultancy, Research Funding.

scholarly journals Increased Early Mortality after Fludarabine and Melphalan Conditioning with Peripheral Blood Grafts in Haploidentical SCT with Post-Transplant Cyclophosphamide

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4496-4496 ◽  
Author(s):  
Luke Eastburg ◽  
David A. Russler-Germain ◽  
Ramzi Abboud ◽  
Peter Westervelt ◽  
John F. DiPersio ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
T Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Early Mortality ◽  
Cell Transplant ◽  
Advisory Committees ◽  
Post Transplant ◽  
Equity Ownership

The use of post-transplant cyclophosphamide (PTCy) in the context of haploidentical stem cell transplant (haplo-SCT) has led to drastically reduced rates of Graft-vs-Host (GvH) disease through selective depletion of highly allo-reactive donor T-cells. Early trials utilized a reduced-intensity Flu/Cy/TBI preparative regimen and bone marrow grafts; however, relapse rates remained relatively high (Luznik et al. BBMT. 2008). This led to the increased use of myeloablative (MA) regimens for haplo-SCT, which have been associated with decreased relapse rates (Bashey et al. J Clin Oncol. 2013). Most studies have used a MA total body irradiation (TBI) based regimen for haplo-SCT. Preparative regimens using fludarabine and melphalan (FluMel), with or without thiotepa, ATG, and/or low dose TBI have also been reported using bone marrow grafts. Reports on the safety and toxicity of FluMel in the haplo-SCT setting with PTCy and peripheral blood stem cell (PBSC) grafts are lacking. In this two-center retrospective analysis, the safety/toxicity of FluMel as conditioning for haplo-SCT was evaluated. We report increased early mortality and toxicity using standard FluMel conditioning and PBSC grafts for patients undergoing haplo-SCT with PTCy. 38 patients at the University of Rochester Medical Center and the Washington University School of Medicine underwent haplo-SCT with FluMel conditioning and PBSC grafts between 2015-2019. Outcomes were measured by retrospective chart review through July 2019. 34 patients (89.5%) received FluMel(140 mg/m2). Two patients received FluMel(100 mg/m2) and two patients received FluMel(140 mg/m2) + ATG. The median age at time of haplo-SCT was 60 years (range 21-73). 20 patients were transplanted for AML, eight for MDS, two for PMF, two for NHL, and five for other malignancies. The median Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI) score was 4 (≥3 indicates high risk). 11 patients had a history of prior stem cell transplant, and 16 patients had active disease prior to their haplo-SCT. Seven patients had sex mismatch with their stem cell donor. Median donor age was 42 (range 21-71). 20 patient deaths occurred by July 2019 with a median follow up of 244 days for surviving patients. Nine patients died before day +100 (D100, "early mortality"), with a D100 non-relapse mortality (NRM) rate of 24%. Median overall and relapse free survival (OS and RFS, respectively) were 197 days (95% CI 142-not reached) and 180 days (95% CI 141-not reached), respectively, for the entire cohort. The 1 year OS and NRM were 29% and 50%. The incidence of grades 2-4cytokine release syndrome (CRS) was 66%, and 52% of these patients were treated with tocilizumab. CRS was strongly associated with early mortality, with D100 NRM of 36% in patients with grade 2-4 CRS compared to 0% in those with grade 0-1. The incidence of acute kidney injury (AKI) was 64% in patients with grade 2-4 CRS, and 8% in those without (p < 0.001). 28% of patients with AKI required dialysis. Grade 2-4 CRS was seen in 54% of patients in remission prior to haplo-SCT and in 92% of those with active disease (p = 0.02). Of the 9 patients with early mortality, 89% had AKI, 44% needed dialysis, and 100% had grade 2-4 CRS, compared to 31%, 10%, and 55% in those without early mortality (p = 0.002, p = 0.02, p = 0.01). Early mortality was not significantly associated with age, HCT-CI score, second transplant, disease status at transplant, total dose of melphalan, volume overload/diuretic use, or post-transplant infection. In conclusion, we observed a very high rate of NRM with FluMel conditioning and PBSC grafts for haplo-SCT with PTCy. The pattern of toxicity was strongly associated with grade 2-4 CRS, AKI, and need for dialysis. These complications may be mediated by excessive inflammation in the context of allo-reactive donor T-cell over-activation. Consistent with this, multiple groups have shown that FluMel conditioning in haplo-SCT is safe when using bone marrow or T-cell depleted grafts. Based on our institutional experiences, we would discourage the use of FluMel as conditioning for haplo-SCT with PTCy with T-cell replete PBSC grafts. Alternative regimens or variations on melphalan-based regimens, such as fractionated melphalan dosing or inclusion of TBI may improve outcomes but further study and randomized controlled trials are needed. This study is limited in its retrospective design and sample size. Figure Disclosures DiPersio: WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Karyopharm Therapeutics: Consultancy; Magenta Therapeutics: Equity Ownership; Celgene: Consultancy; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; NeoImmune Tech: Research Funding; Amphivena Therapeutics: Consultancy, Research Funding; Bioline Rx: Research Funding, Speakers Bureau; Macrogenics: Research Funding, Speakers Bureau; Incyte: Consultancy, Research Funding; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees. Liesveld:Onconova: Other: Data safety monitoring board; Abbvie: Membership on an entity's Board of Directors or advisory committees.

Selinexor Demonstrates Marked Synergy with Dexamethasone (Sel-Dex) in Preclinical Models and in Patients with Heavily Pretreated Refractory Multiple Myeloma (MM)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4773-4773 ◽  
Author(s):  
Christine I. Chen ◽  
Martin Gutierrez ◽  
David S. Siegel ◽  
Joshua R. Richter ◽  
Nina Wagner-Johnston ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Transcriptional Activation ◽  
Nuclear Export ◽  
Research Funding ◽  
Phase 1 ◽  
Advisory Committees ◽  
Nuclear Retention ◽  
Heavily Pretreated ◽  
Equity Ownership

Abstract Introduction: The nuclear export protein exportin 1, (XPO1) is overexpressed in a wide variety of cancers including MM and often correlate with poor prognosis. Selinexor (KPT-330) is an oral Selective Inhibitor of Nuclear Export (SINE) XPO1 antagonist in Phase 1 and 2 clinical studies. Selinexor forces nuclear retention and reactivation of tumor suppressor proteins (TSPs) and reduction of many proto-oncogenes, including MDM2, MYC and Cyclin D. In addition, selinexor potently deactivates NF-κB, through forced nuclear retention of IκBα. Together these effects induce selective apoptosis in MM cells and inhibition of NF-κB dependent osteoclast activation. XPO1 is also responsible for nuclear export of the glucocorticoid receptor (GR). We hypothesized that selinexor will enhance the activity of dexamethasone (DEX)-bound GR, resulting in synergistic tumor cell killing. Methods: In vitro tumor cell viability measurements were based on MTT (CellTiter 96¨/Promega) and combination indices were calculated using CalcuSyn software. For xenograft studies, utilized NOD-SCID mice with subcutaneous inoculation of MM.1s cells. GR nuclear localization was measured with immunofluorescent anti-GR (phosphor-S211) antibody and quantitative imaging. To assess GR transcriptional activation, GR binding to a GCR consensus sequence was measured in nuclear extracts using an ELISA method (GR ELISA kit/Affymetrix). Patients (pts) with heavily pretreated refractory MM were dosed with oral selinexor at doses of up to 60 mg/m2 (8-10 doses/4 wk cycle) as part of a Phase 1 program in advanced hematological malignancies. Response we defined based on the IMWG criteria. The effect of combining DEX with selinexor was analyzed in all pts who received selinexor at moderate to high doses (30-60 mg/m2). Safety and efficacy were analyzed separately in three groups: no DEX, <20 mg DEX and 20 mgs DEX. Results: In MM.1s cells Sel-Dex showed synergy for nuclear retention of the DEX activated GR (Ser211-phosphorylated) and concomitant GR transcriptional activation. Sel-Dex showed highly synergistic cytotoxicity in MM.1s cells in vitro and in vivo, with a corresponding increase in apoptosis. Selinexor alone was potently cytotoxic in the DEX resistant MM cell lines MM.1R and ANBL6, but addition of DEX provided no additional effect. Twenty-eight pts with heavily pretreated refractory MM (16 M, 12 F; median age 62; ECOG PS 0/1: 7/21; median prior regimens: 6) received selinexor at 30 – 60 mg/m2 with either 0, <20, or 20 mgs DEX. All pts have received a proteasome inhibitor and an Imid and the majority of the pts have received pomalidomide (68%) and/or carfilzomib (36%). The most common Grade 1/2 AEs for these three groups were: nausea (82%/86%/70%), fatigue (55%/86%/40%), anorexia (36%/71%/60%), and vomiting (36%/57%/10%). Of the 28 pts treated; 10 heavily pretreated refractory MM pts treated with a combination of selinexor (45 mg/m2 twice weekly) and DEX (20 mg with each selinexor dose) were found to have dramatically improved disease response (n=10, ORR 60%), with one stringent complete response (sCR, 10%), 5 partial responses (PR, 50%) and clinical benefit rate (CBR) rate of 80% (Figure 1). Treatment with ³30mg/m2 selinexor and <20 mg DEX (n=7), resulted in ORR of 14% and CBR of 86%, while treatment with selinexor (30-60 mg/m2) without DEX (n=12) showed best response of stable disease (50%). Sel-Dex was also associated with an increase in time on study relative to selinexor alone, with 7 of out 10 pts in the 20 mg DEX combo group still on study (11-25 weeks). Five additional pts were treated with selinexor at a dose of 60 mg/m2 in combination with 20 mg DEX. Response evaluation is pending. Conclusions: Sel-Dex combination is markedly synergistic in preclinical models, which is supported by the preliminary clinical data presented. One potential mechanism underlying this synergy is the amplification of GR activity due the combined effects of selinexor-induced nuclear retention of activated GR coupled with DEX-mediated GR agonism. These results provide a promising basis for the continuing study of Sel-Dex for treatment of pts with refractory MM. Phase 2 studies of Sel-Dex in pts with MM refractory to both pomalidomide and carfilzomib are planned for early 2015. Disclosures Chen: Celgene: Honoraria; Janssen: Honoraria. Off Label Use: Lenalidomide maintenance therapy after ASCT. Gutierrez:Senesco: PI Other. Siegel:Celgene, Millennium, Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baz:Celgene: Research Funding; Millennium: Research Funding; Bristol Myers Squibb: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding. Kukreti:Celgene: Honoraria. Azmi:Karyopharm Therpeutics: Research Funding. Kashyap:Karyopharm Therapeutics: Employment. Landesman:Karyopharm Therapeutics: Employment. Marshall:Karyopharm Therpeutics: Employment. McCartney:Karyopharm Therpeutics: Employment. Saint-Martin:Karyopharm Therpeutics: Employment. Norori:Karyopharm Therpeutics: Consultancy. Savona:Karyopharm Therpeutics: Membership on an entity's Board of Directors or advisory committees. Rashal:Karyopharm Therapeutics: Employment. Carlson:Karyopharm Therapeutics: Employment. Mirza:Karyopharm Therpeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Kauffman:Karyopharm Therapeutics: Employment, Equity Ownership. Reece:Millennium: Honoraria, Research Funding; Millennium: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Merck: Research Funding; Merck: Research Funding; BMS: Research Funding; BMS: Research Funding; Novartis: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen : Honoraria; Amgen : Honoraria.

scholarly journals Gabarap Loss Mediates Immune Escape in High Risk Multiple Myeloma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 891-891
Author(s):  
Annamaria Gulla ◽  
Eugenio Morelli ◽  
Mehmet K. Samur ◽  
Cirino Botta ◽  
Megan Johnstone ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Clinical Outcome ◽  
Board Of Directors ◽  
Research Funding ◽  
Immune Escape ◽  
Publicly Traded ◽  
Advisory Committees

Abstract Immune therapies including CAR T cells and bispecific T cell engagers are demonstrating remarkable efficacy in relapsed refractory myeloma (MM). In this context, we have recently shown that proteasome inhibitor bortezomib (BTZ) results in immunogenic cell death (ICD) and in a viral mimicry state in MM cells, allowing for immune recognition of tumor cells. Induction of a robust anti-MM immune response after BTZ was confirmed both in vitro and in vivo: treatment of 5TGM1 MM cells with BTZ induced tumor regression associated with memory immune response, confirmed by ELISPOT of mouse splenocytes. We have confirmed the obligate role of calreticulin (CALR) exposure in phagocytosis and the ICD process, since BTZ-induced ICD is impaired in CALR KO MM cells both in vitro and in vivo. We further showed that the therapeutic efficacy of BTZ in patients was correlated with ICD induction: BTZ-induced ICD signature was positively correlated with OS (p=0.01) in patients enrolled in the IFM/DFCI 2009 study. Together, these studies indicate that ICD is associated with long-term response after BTZ treatment. In this work, we reasoned that genomic or transcriptomic alterations associated with shorter survival of MM patients after BTZ treatment may impair activation of the ICD pathway. To this aim, we performed a transcriptomic analysis of purified CD138+ cells from 360 newly diagnosed, clinically-annotated MM patients enrolled in the IFM/DFCI 2009 study. By focusing on genes involved in the ICD process, we found that low levels of GABA Type A Receptor-Associated Protein (GABARAP) were associated with inferior clinical outcome (EFS, p=0.0055). GABARAP gene locus is located on chr17p13.1, a region deleted in high risk (HR) MM with unfavorable prognosis. Remarkably, we found that correlation of low GABARAP levels with shorter EFS was significant (p=0.018) even after excluding MM patients with del17p; and GABARAP is therefore an independent predictor of clinical outcome. GABARAP is a regulator of autophagy and vesicular trafficking, and a putative CALR binding partner. Interestingly, among a panel of MM cell lines (n=6), BTZ treatment failed to induce exposure of CALR and MM cell phagocytosis by DCs in KMS11 cells, which carry a monoallelic deletion of GABARAP. This effect was rescued by stable overexpression of GABARAP. Moreover, CRISPR/Cas9-mediated KO of GABARAP in 3 ICD-sensitive cell lines (AMO1, H929, 5TGM1) abrogated CALR exposure and ICD induction by BTZ. GABARAP add-back by stable overexpression in KO clones restored both CALR exposure and induction of ICD, confirming GABARAP on-target activity. Similarly, pre-treatment of GABARAP KO cells with recombinant CALR restored MM phagocytosis, further confirming that GABARAP impairs ICD via inhibition of CALR exposure. Based on these findings, we hypothesized that GABARAP loss may alter the ICD pathway via CALR trapping, resulting in the ICD resistant phenotype observed in GABARAP null and del17p cells. To this end, we explored the impact of GABARAP KO on the CALR protein interactome, in the presence or absence of BTZ. Importantly, GABARAP KO produced a significant increase of CALR binding to stanniocalcin 1 (STC1), a phagocytosis checkpoint that mediates the mitochondrial trapping of CALR, thereby minimizing its exposure upon ICD. Consistently, GABARAP KO also affected CALR interactome in BTZ-treated cells, which was significantly enriched in mitochondrial proteins. Importantly, co-IP experiments confirmed GABARAP interaction with STC1. These data indicate a molecular scenario whereby GABARAP interacts with STC1 to avoid STC1-mediated trapping of CALR, allowing for the induction of ICD after treatment with ICD inducers; on the other hand, this mechanism is compromised in GABARAP null or del17p cells, and the STC1-CALR complex remains trapped in the mitochondria, resulting in ICD resistance. To functionally validate our findings in the context of the immune microenvironment, we performed mass Cytometry after T cell co-culture with DCs primed by both WT and GABARAP KO AMO1 clones. And we confirmed that treatment of GABARAP KO clones with BTZ failed to activate an efficient T cell response. In conclusion, our work identifies a unique mechanism of immune escape which may contribute to the poor clinical outcome observed in del17p HR MM patients. It further suggests that novel therapies to restore GABARAP may allow for the induction of ICD and improved patient outcome in MM. Disclosures Bianchi: Jacob D. Fuchsberg Law Firm: Consultancy; MJH: Honoraria; Karyopharm: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Richardson: AstraZeneca: Consultancy; Regeneron: Consultancy; Protocol Intelligence: Consultancy; Secura Bio: Consultancy; GlaxoSmithKline: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Takeda: Consultancy, Research Funding; AbbVie: Consultancy; Karyopharm: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding. Chauhan: C4 Therapeutics: Current equity holder in publicly-traded company; Stemline Therapeutics, Inc: Consultancy. Munshi: Legend: Consultancy; Karyopharm: Consultancy; Amgen: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Abbvie: Consultancy; Takeda: Consultancy; Adaptive Biotechnology: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Bristol-Myers Squibb: Consultancy. Anderson: Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Scientific Founder of Oncopep and C4 Therapeutics: Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Mana Therapeutics: Membership on an entity's Board of Directors or advisory committees.

scholarly journals The 3-Drug Combination Treatment ART838, ABT199 Plus Sorafenib Is Effective Against AML Xenografts, Possibly Via Cooperative Targeting of MCL1

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4044-4044
Author(s):  
Blake S Moses ◽  
Jennifer Fox ◽  
Xiaochun Chen ◽  
Samantha McCullough ◽  
Sang Ngoc Tran ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Board Of Directors ◽  
Cell Lines ◽  
Drug Combination ◽  
Research Funding ◽  
Leukemia Cell ◽  
Advisory Committees ◽  
Leukemia Cell Lines ◽  
Equity Ownership

Abstract Antimalarial artemisinins have broad antineoplastic activity in vitro, are well tolerated and inexpensive, and can be parenterally or orally administered in humans. Artemisinin-derived trioxane diphenylphosphate dimer 838 (ART838; a potent artemisinin-derivative) inhibited acute leukemia growth in vivo and in vitro, at doses where normal human CD34+ hematopoietic stem-progenitor cell clonogenicity was essentially unaffected (Fox et al, Oncotarget 2016, PMID: 26771236). In our focused drug combination screen for drugs that synergize with ART838, the only BCL2 inhibitors in the screen library of 111 emerging antineoplastic compounds, navitoclax (ABT737) and venetoclax (ABT199; FDA-approved), were identified as 2 of the top 3 candidates. Synergies between ART838 and BCL2 inhibitors were validated in multiple acute leukemia cell lines and primary cases. This ART838-BCL2 inhibitor synergy may be due to reduced levels of MCL1 protein that we and others have observed in multiple acute leukemia cell lines and primary cases treated with artemisinins (Budhraja et al, Clin Cancer Res 2017, PMID: 28974549). Treatment of acute leukemia xenografts with the ART838 plus ABT199 combination reduced leukemia growth rates and prolonged survivals, compared to vehicle or either ART838 or ABT199 alone. To add to the efficacy of this ART838 plus ABT199 treatment regimen, we sought to rationally add a third low-toxicity active antileukemic agent. Sorafenib (SOR; FDA-approved) inhibits multiple kinases which may mediate its antileukemic activity, with the importance of the targets varying from case to case; e.g. FLT3 is an important target in many AMLs. In addition, several reports have found that SOR reduces MCL1 protein stability and translation through inhibition of the ERK and PI3K pathways (Wang et al, Clin Cancer Res 2016, PMID: 26459180; Huber et al, Leukemia 2011, PMID: 21293487). In all acute leukemia cell lines tested, we observed large reductions in MCL1 protein levels with SOR treatment, which may further rationalize the addition of SOR to our ART838 plus ABT199 antileukemic regimen. We had previously observed strong in vitro synergy between ART838 and SOR (PMID: 26771236). Treatment of acute leukemia xenografts with the ART838 plus SOR combination reduced leukemia xenograft growth rates and prolonged survivals, compared to single drugs. Mice bearing luciferase-labelled acute leukemia xenografts were treated (PO daily x5) with single drug or 2-drug or 3-drug combinations of ART838, ABT199, and SOR, each at their individual maximally tolerated doses. Treatment with this 3-drug combination caused rapid regression of luciferase-labelled MV4;11 AML xenografts (Fig 1A). The 5-day treatment cycles were repeated every other week, and mice receiving this 3-drug combination survived >4 times longer than vehicle-treated mice (Fig 1B). Mouse body weights were stable during treatment. Although myelosuppression is the human clinical dose-limiting toxicity of each of these 3 drugs, mouse blood cell counts during 3-drug combination treatment were in the normal range. Treatment of a luciferase-labelled primary AML leukemia xenograft with this 3-drug combination reduced leukemia growth more than the single drugs or 2-drug combinations (Fig 1C). Assessment of efficacy and pharmacokinetics-pharmacodynamics against diverse acute leukemia xenografts will test this combination of ART838, ABT199 plus SOR as a rational low-toxicity drug triad for treatment of acute leukemias and potentially other cancers. Disclosures Fox: Intrexon Corporation: Employment. Tyner:Genentech: Research Funding; Janssen: Research Funding; AstraZeneca: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Constellation: Research Funding; Array: Research Funding; Takeda: Research Funding; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; Aptose: Research Funding. Civin:ConverGene LLC: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; GPB Scientific LLC: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; 3DBioWorks Inc: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; BD (Becton Dickinson): Honoraria.

scholarly journals 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 ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 742-742 ◽  
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 (&gt;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&lt;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 (&gt;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 &gt;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 &gt;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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