scholarly journals Triple Gene-Modified iPSC-Derived NK Cells Combined with Daratumumab for Targeted Immunotherapy Against AML

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 57-58
Author(s):  
Frank Cichocki ◽  
Ryan Bjordahl ◽  
Karrune Woan ◽  
Zachary Davis ◽  
Greg Bonello ◽  
...  

Approximately 19,940 new cases of acute myeloid leukemia (AML) will be diagnosed in 2020 with an estimated 11,180 deaths, which has remained steady for 3 decades. We established that allogeneic natural killer (NK) cell infusions have an antileukemic effect and induce remission in 25-40% of relapsed/refractory AML patients. After hundreds of individual donor product infusions, we noted therapeutic limitations to include effector potency, cell numbers,persistence, specificity and exportability. To overcome these barriers, we developed a robust genetic editing and manufacturing platform for the uniform engineering and expansion of high-quality NK cells derived from induced pluripotent stem cells (iPSCs). This manufacturing system allows efficient production of iPSC-derived NK (iNK) cells engineered to enhance persistence and potency, and enables distribution of highly homogenous iNK cells to multiple clinical sites and multi-dosing to treat patients on-demand with advanced cancer. We hypothesized that iNK cells could be combined with the anti-CD38 monoclonal antibody daratumumab (dara) to directly target various tumors and harness their antibody-dependent cellular cytotoxicity (ADCC) potential. Previously, we reported on our ability to effectively target multiple myeloma with our FT538 program (the iNK defined below), now FDA approved for clinical trials. Here we discuss applying these same engineered iNK cells to specifically target and kill AML blasts induced to upregulate CD38 by retinoic acid exposure. We utilized iNK cells expressing a high-affinity, non-cleavable version of CD16 (the Fc receptor that mediates ADCC) termed hnCD16 alone or combined with CD38 knockout (KO) to prevent dara-mediated NK cell fratricide (Fig. 1A). CD38 KO iNK cells had intact calcium flux in response to ionomycin or CD16 crosslinking (Fig. 1B). Adding dara to peripheral blood NK cells or hnCD16 iNK cells triggered ADCC-mediated fratricide, while hnCD16/CD38 KO iNK cells that cannot be targeted by dara were unaffected (Fig 1C). CD38, expressed intracellularly and on the plasma membrane, functions as an NADase, degrading nicotinamide adenine dinucleotide (NAD+) into ADP-ribose and nicotinamide. Because NAD+ levels influence several key metabolic pathways, we assessed the impact of CD38 KO on iNK cell metabolism. We found that, relative to hnCD16 iNK cells, hnCD16/CD38 KO iNK cells had significantly higher intracellular NAD+, NADH, and ATP levels (Fig. 1D). Additionally, hnCD16/CD38 KO iNK cells exhibited elevated mitochondrial oxidative phosphorylation (Fig. 1E) and marked resistance to oxidative stress to hydrogen peroxide exposure (Fig. 1F). Together, these results demonstrate a significant enhancement of NK cell mitochondrial oxidative phosphorylation and redox homeostasis in iNK CD38 KO cells. To enhance hnCD16/CD38 KO iNK cells further, we incorporated a third modification consisting of an IL-15 receptor signaling complex (IL-15RF). This receptor complex is expressed on the cell surface and provides IL-15 signals required for NK cell survival and proliferation independent of exogenous cytokine. To determine the efficacy of hnCD16/CD38 KO/IL-15RF iNK cells combined with dara to target AML, we first assessed CD38 expression on THP-1 cells (an AML cell line) and primary AML blasts incubated with or without retinoic acid. We observed high CD38 expression on both THP-1 cells and primary AML cells further elevated with retinoic acid treatment (Fig. 1G). THP-1 and primary AML cells were labeled with CellTrace dye and used as targets for killing assays using hnCD16/CD38 KO/IL-15RF iNK cells. Compared to hnCD16/CD38 KO/IL-15RF iNK cells cultured with targets alone, adding dara led to higher target cell killing, especially after retinoic acid exposure (Fig. 1H). In 12-hour live imaging experiments testing iNK cell cytotoxicity against THP-1 cells, similar results were observed (Fig. 1I). Collectively, our results show that utilizing the iNK cell platform to uniformly express hnCD16 and IL15RF combined with complete CD38 KO is an effective strategy to promote effective ADCC against CD38+ cells in the absence of fratricide, and that CD38 KO reprograms NK cells for higher oxidative metabolic fitness for improved persistence and anti-tumor function. Furthermore, we have generated proof-of-concept data supporting triple gene-modified iNK cells combined with dara as a novel AML immunotherapy. Disclosures Cichocki: Fate Therapeutics, Inc: Consultancy, Patents & Royalties, Research Funding. Bjordahl:Fate Therapeutics: Current Employment. Bonello:Fate Therapeutics, Inc: Current Employment. Mahmood:Fate Therapeutics, Inc: Current Employment. Rogers:Fate Therapeutics, Inc: Current Employment. Ge:Fate Therapeutics, Inc: Current Employment. Lee:Fate Therapeutics, Inc.: Current Employment. Felices:GT Biopharma: Consultancy. Walcheck:Fate Therapeutics: Consultancy, Research Funding. Blazar:Fate Therapeutics Inc.: Research Funding; KidsFirst Fund: Research Funding; Magenta Therapeutics: Consultancy; Childrens' Cancer Research Fund: Research Funding; BlueRock Therapeutics: Research Funding; BlueRock Therapeuetic: Consultancy; Tmunity: Other: Co-founder. Valamehr:Fate Therapeutics, Inc: Current Employment, Current equity holder in publicly-traded company. Miller:GT Biopharma: Consultancy, Patents & Royalties, Research Funding; Onkimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Nektar: Honoraria, Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics, Inc: Consultancy, Patents & Royalties, Research Funding; Vycellix: Consultancy. OffLabel Disclosure: FT538 is a genetically modified induced pluripotent stem cell derived NK cell product that can be combined with daratumumab to target CD38 on AML after retinoid acid induction.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3215-3215 ◽  
Author(s):  
Frank Cichocki ◽  
Karrune Woan ◽  
Cheng-Ying Wu ◽  
Bruce R. Blazar ◽  
Ryan Bjordahl ◽  
...  

Cytolytic effector lymphocytes must contend with unfavorable microenvironments when infiltrating sites of infection or malignancy. Tumor cells typically have high levels of oxidative stress and produce reactive oxygen species (ROS) that suppress the cytotoxic functions of both natural killer (NK) cells and CD8+ T cells. Levels of activated granulocytes that release ROS are also elevated in cancer patients. Free radicals, such as ROS, cause detrimental cellular effects including protein oxidation, lipid peroxidation and DNA damage. Chronic viral infections, including CMV, are also associated with increased oxidative stress. We hypothesized that adaptive NK cells, which arise specifically in response to CMV, could have properties that allow these cells to persist and retain function in high oxidative stress environments. Adaptive NK cells are present in the peripheral blood of many otherwise healthy CMV seropositive individuals and expand in response to CMV reactivation in hematopoietic cell transplant (HCT) patients. Mounting evidence suggests that CMV peptides presented by HLA-E on infected cells can trigger the expansion of adaptive NK cells expressing the activating receptor NKG2C. The majority of NKG2C-positive adaptive NK cells co-express the terminal maturation marker CD57. Work by our group and others has shown that adaptive NK cells exhibit enhanced antibody-dependent cellular cytotoxicity (ADCC) and interferon (IFN)-γ production relative to canonical NK cells, appear to persist long-term and have metabolic attributes similar to memory CD8+ T cells. We also reported clinical correlations between adaptive NK cell numbers and reduced relapse risk in HCT patients with hematologic malignancies. Here, we show that CD38 expression is markedly reduced on adaptive NK cells from CMV seropositive individuals. This observation was first made from analyses of RNA-seq data comparing adaptive and canonical NK cells and was validated by flow cytometry (Figure 1A). CD38 is expressed both intracellularly and on the plasma membrane and functions as an NADase, degrading nicotinamide adenine dinucleotide (NAD+) into ADP-ribose and nicotinamide. NAD+ is a necessary cofactor for the sirturin family of protein deacetylases, which protect against oxidative stress. We hypothesized that CD38 downregulation in adaptive NK cells could be associated with more resistance to oxidative stress-induced cell death through increased NAD+ levels and sirturin activity. To determine whether there was a connection between CD38 expression and resistance to oxidative stress, we isolated NK cells from the peripheral blood of CMV seropositive donors and cultured them overnight with or without 15 mM H2O2 (hydrogen peroxide), known to induce oxidative stress and cell death. We found that NKG2C+ adaptive NK cells were markedly more resistant to oxidative stress-induced cell death compared to NKG2C-negative canonical NK cells as determined by annexin V and a fixable amine-reactive dye (LIVE/DEAD) that can permeate damaged membranes of dead cells and react with interior amines (Figure 1B). Similar results were observed in assays where NK cells from CMV seropositive donors were co-cultured with neutrophils pre-activated with phorbol 12-myristate 13-acetate (PMA) to induce the release of reactive oxygen species. To determine whether CD38 expression is directly associated with the NK cell response to oxidative stress, we generated induced pluripotent stem cell (iPSC) lacking CD38 through CRISPR/Cas9 gene editing that were differentiated into NK cells and tested for their ability to resist oxidative stress-induced death. Compared to control iPSC-derived NK (iNK) cells that express high levels of CD38 (Figure 1C), a substantially larger percentage of CD38 knockout iNK cells were viable when cultured overnight with H2O2 (Figure 1D). Our results have implications for adoptive immunotherapy to treat patients with cancer where a major goal is to manufacture cytotoxic cells that can persist and function in a tumor environment that contains high levels of oxidative radicals. We are exploring other cell stressors of high translational relevance such as freeze/thaw stress in adaptive and CD38 knockout cells that will be critical for cell therapy platforms. Disclosures Cichocki: Fate Therapeutics, Inc: Research Funding. Blazar:Kamon Pharmaceuticals, Inc: 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; Regeneron Pharmaceuticals: 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; Childrens' Cancer Research Fund: Research Funding; KidsFirst Fund: Research Funding; Tmunity: Other: Co-Founder; BlueRock Therapeutics: Membership on an entity's Board of Directors or advisory committees. Bjordahl:Fate Therapeutics, Inc.: Employment. Valamehr:Fate Therapeutics, Inc: Employment. Miller:Fate Therapeutics, Inc: Consultancy, Research Funding; CytoSen: Membership on an entity's Board of Directors or advisory committees; OnKImmune: Membership on an entity's Board of Directors or advisory committees; Dr. Reddys Laboratory: Membership on an entity's Board of Directors or advisory committees; Moderna: Membership on an entity's Board of Directors or advisory committees; GT BioPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. OffLabel Disclosure: NK cells


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3199-3199 ◽  
Author(s):  
Subhashis Sarkar ◽  
Sachin Chauhan ◽  
Arwen Stikvoort ◽  
Alessandro Natoni ◽  
John Daly ◽  
...  

Abstract Introduction: Multiple Myeloma (MM) is a clonal plasma cell malignancy typically associated with the high and uniform expression of CD38 transmembrane glycoprotein. Daratumumab is a humanized IgG1κ CD38 monoclonal antibody (moAb) which has demonstrated impressive single agent activity even in relapsed refractory MM patients as well as strong synergy with other anti-MM drugs. Natural Killer (NK) cells are cytotoxic immune effector cells mediating tumour immunosurveillance in vivo. NK cells also play an important role during moAb therapy by inducing antibody dependent cellular cytotoxicity (ADCC) via their Fcγ RIII (CD16) receptor. Furthermore, 15% of the population express a naturally occurring high affinity variant of CD16 harbouring a single point polymorphism (F158V), and this variant has been linked to improved ADCC. However, the contribution of NK cells to the efficacy of Daratumumab remains debatable as clinical data clearly indicate rapid depletion of CD38high peripheral blood NK cells in patients upon Daratumumab administration. Therefore, we hypothesize that transiently expressing the CD16F158V receptor using a "safe" mRNA electroporation-based approach, on CD38low NK cells could significantly enhance therapeutic efficacy of Daratumumab in MM patients. In the present study, we investigate the optimal NK cell platform for generating CD38low CD16F158V NK cells which can be administered as an "off-the-shelf"cell therapy product to target both CD38high and CD38low expressing MM patients in combination with Daratumumab. Methods: MM cell lines (n=5) (MM.1S, RPMI-8226, JJN3, H929, and U266) and NK cells (n=3) (primary expanded, NK-92, and KHYG1) were immunophenotyped for CD38 expression. CD16F158V coding m-RNA transcripts were synthesized using in-vitro transcription (IVT). CD16F158V expression was determined by flow cytometry over a period of 120 hours (n=5). 24-hours post electroporation, CD16F158V expressing KHYG1 cells were co-cultured with MM cell lines (n=4; RPMI-8226, JJN3, H929, and U266) either alone or in combination with Daratumumab in a 14-hour assay. Daratumumab induced NK cell fratricide and cytokine production (IFN-γ and TNF-α) were investigated at an E:T ratio of 1:1 in a 14-hour assay (n=3). CD38+CD138+ primary MM cells from newly diagnosed or relapsed-refractory MM patients were isolated by positive selection (n=5), and co-cultured with mock electroporated or CD16F158V m-RNA electroporated KHYG1 cells. CD16F158V KHYG1 were also co-cultured with primary MM cells from Daratumumab relapsed-refractory (RR) patients. Results: MM cell lines were classified as CD38hi (RPMI-8226, H929), and CD38lo (JJN3, U266) based on immunophenotyping (n=4). KHYG1 NK cell line had significantly lower CD38 expression as compared to primary expanded NK cells and NK-92 cell line (Figure 1a). KHYG1 electroporated with CD16F158V m-RNA expressed CD16 over a period of 120-hours post-transfection (n=5) (Figure 1b). CD16F158V KHYG1 in-combination with Daratumumab were significantly more cytotoxic towards both CD38hi and CD38lo MM cell lines as compared to CD16F158V KHYG1 alone at multiple E:T ratios (n=4) (Figure 1c, 1d). More importantly, Daratumumab had no significant effect on the viability of CD38low CD16F158V KHYG1. Moreover, CD16F158V KHYG1 in combination with Daratumumab produced significantly higher levels of IFN-γ (p=0.01) upon co-culture with CD38hi H929 cell line as compared to co-culture with mock KHYG1 and Daratumumab. The combination of CD16F158V KHYG1 with Daratumumab was also significantly more cytotoxic to primary MM cell ex vivo as compared to mock KHYG1 with Daratumumab at E:T ratio of 0.5:1 (p=0.01), 1:1 (p=0.005), 2.5:1 (p=0.003) and 5:1 (p=0.004) (Figure 1e). Preliminary data (n=2) also suggests that CD16F158V expressing KHYG1 can eliminate 15-17% of primary MM cells from Daratumumab RR patients ex vivo. Analysis of more Daratumumab RR samples are currently ongoing. Conclusions: Our study provides the proof-of-concept for combination therapy of Daratumumab with "off-the-shelf" CD38low NK cells transiently expressing CD16F158V for treatment of MM. Notably, this approach was effective against MM cell lines even with low CD38 expression (JJN3) and primary MM cells cultured ex vivo. Moreover, the enhanced cytokine production by CD16F158V KHYG1 cells has the potential to improve immunosurveillance and stimulate adaptive immune responses in vivo. Disclosures Sarkar: Onkimmune: Research Funding. Chauhan:Onkimmune: Research Funding. Stikvoort:Onkimmune: Research Funding. Mutis:Genmab: Research Funding; OnkImmune: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding; Celgene: Research Funding; Novartis: Research Funding. O'Dwyer:Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; BMS: Research Funding; Glycomimetics: Research Funding; Onkimmune: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5536-5536 ◽  
Author(s):  
Emma Nolan ◽  
Arwen Stikvoort ◽  
Mark Gurney ◽  
Nutsa Burduli ◽  
Lucy Kirkham-McCarthy ◽  
...  

Introduction: Chimeric Antigen Receptor (CAR) based cellular-immunotherapies have demonstrated significant clinical efficacy in haematological malignancies. However, the progress of cellular-immunotherapy for the treatment of Acute Myeloid Leukaemia (AML) has failed to gain momentum due to the lack of targetable tumour specific antigens. CD38 is a transmembrane glycoprotein expressed in lymphoid and myeloid cells with high expression in plasma B-cells, and is a well validated target for anti-CD38 therapy in Myeloma. A recent study has furthermore shown that a proportion of AML patients express CD38 on their leukemic blasts. TNF-related apoptosis-inducing ligand (TRAIL) receptor DR4 is another targetable antigen which has been shown to be expressed in 70% of AML patients. In this study, we investigate the therapeutic efficacy of "affinity-optimized" variant(s) of CD38 CAR and membrane bound TRAIL on NK-cell based platforms which can target AML blasts with high expression of CD38 (CD38high AML). The CAR variant is a CAR which binds with lower affinity to CD38 expressed on healthy immune cells such as CD38positive NK cells, while targeting CD38high AML. The membrane bound TRAIL variant (TRAIL4c9) is a mutant which binds with higher affinity to TRAIL-DR4 on AML cells, whilst avoiding binding to decoy receptors. We hypothesize that genetically modifying NK cells to express "affinity optimized" CD38 CARand/or TRAIL4c9 can effectively eliminate CD38high AML cells. Methods: AML cell lines THP-1, U937, and KG1a were immunophenotyped for CD38 and TRAIL-DR4 expression. Retrovirally transduced CD38 CAR-KHYG1 NK cells were used as immune effector cells and were co-cultured with AML cell lines in cytotoxicity assays. CD38low AML cell line KG1a was pre-treated with 10nM all-trans-retinoic acid (ATRA) to upregulate CD38 expression and were subsequently co-cultured with CD38 CAR-KHYG1 in cytotoxicity assays. CD38 CAR-KHYG1 was also co-cultured with n=4 patient derived AML cells in cytotoxicity assays. Using Maxcyte GT electroporation system primary donor derived IL-2 activated NK cells were either mock electroporated, or electroporated with TRAIL4c9 m-RNA orCD38 CAR m-RNA and subsequently co-cultured with THP-1 or ATRA pre-treated KG1a in a cytotoxicity assay. Expression of pro-apoptotic, anti-apoptotic and ligands for checkpoint inhibitory receptors was analysed by immunoblotting or flowcytometry. Results: Based on immunophenotyping, we classified AML cell lines as CD38high (THP-1), CD38moderate (U937) and CD38low (KG1a). CD38 CAR-KHYG1 was significantly more cytotoxic than MOCK KHYG1 against CD38high THP-1, at E:T ratios of 2.5:1, 5:1 and 10:1. CD38 CAR-KHYG1 were also more cytotoxic than MOCK KHYG1 against CD38moderate U937 at multiple E:T ratios; albeit the increase in cytotoxicity was at a much lower level in comparison to THP-1 (Fig 1a). Pre-treatment of CD38low KG1a cells with 10nM ATRA upregulated the cell surface expression of CD38, which were subsequently eliminated by CD38 CAR KHYG1 at E:T ratios of 2.5:1, 5:1 and 10:1. KG1a was intrinsically resistant to NK cells as compared to THP-1 and U937 (Fig 1b). This could partly be explained by the high intracellular expression of Bcl-xL, and higher cell surface expression of Nectin-1 and Sialic acid which are the ligands for checkpoint inhibitory receptors CD96 and Siglec-7/9 respectively on NK cell (Fig 1c). CD38 CAR-KHYG1 mounted a potent cytotoxic response against primary CD45intermediate AML blasts (n=4 patients) at multiple E:T ratios, and the extent of CAR induced cytotoxicity correlated with the cell surface CD38 expression on the primary AML blasts (R2=0.87) (Fig 1d,e). TRAIL4c9 or CD38 CAR m-RNA electroporated primary donor-derived NK cells were also potent in eliminating THP-1 and ATRA pre-treated KG1a at multiple E:T ratios (Fig 1f). This demonstrates the potential of therapeutically treating AML patients, with high CD38 expression, with a combination of NK cells expressing "affinity-optimized" CD38 CAR and membrane bound TRAIL variant. Conclusion: The study demonstrates the therapeutic potential of an "affinity-optimized" CD38 CAR NK cell-based therapy, which can potentially be combined with membrane bound TRAIL expressing NK cells to target CD38high AML. In patients with CD38low expressing AML blasts, patients could be pre-treated with ATRA followed by the combination therapy of CD38 CAR and TRAIL expressing NK cells. Disclosures Stikvoort: Onkimmune Ltd., Ireland: Research Funding. Kirkham-McCarthy:Onkimmune Ltd., Ireland: Research Funding. Van De Donk:Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; AMGEN: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Mutis:Celgene: Research Funding; Janssen Pharmaceuticals: Research Funding; Amgen: Research Funding; BMS: Research Funding; Novartis: Research Funding; Aduro: Research Funding; Onkimmune: Research Funding. Sarkar:Onkimmune: Research Funding. O'Dwyer:Onkimmune: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; GlycoMimetics Inc: Research Funding; AbbVie: Consultancy; BMS: Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 621-621
Author(s):  
Zachary Davis ◽  
Martin Felices ◽  
Todd R Lenvik ◽  
Sujan Badal ◽  
Peter Hinderlie ◽  
...  

Checkpoint blockade has become a promising immunotherapy for the treatment of a variety of malignancies. In particular, the receptor programmed death-1 (PD-1) has become a focus of intense study due to its expression on and negative regulation of T-cell function. The ligand for PD-1, PD-L1, is upregulated on many tumors and, as a result, can suppress antigen-specific T-cells thereby limiting their anti-tumor response. Pharmacological PD-1/PD-L1 axis disruption can occur with either Pembrolizumab and Nivolumab (PD-1 antagonists) and Avelumab and Atezolizumab (PD-L1 antagonists). These antibodies (mAbs) are being used to treat melanoma, non-small cell lung cancer, kidney, bladder and head and neck cancer with varying degrees of success. Like T-cells, natural killer cells (NK) also have potent antitumor cytolytic properties. The expression and functional effects of PD-1 on NK cells remain unclear due to difficulties in receptor detection and efficacy of receptor blockade by available commercial reagents. While some studies have been unable to detect PD-1 on resting NK cells, others have identified PD-1 expression only on specific NK populations under certain conditions (e.g. Cytokine stimulation or virus infection). Here, we identify PD-1 expression on peripheral blood NK cells. Using commercial reagents (Figure 1A) and a FITC-labeled clinical mAb (Pembrolizumab, Pembro), we detect low yet consistent PD-1 expression on all circulating, resting NK cells. Since FITC-Pembro mean fluorescent intensity was low and a high proportion of FITC labeled NK cells overlapped with the isotype control (Figure 1B), we designed a short-chain variable fragment (scFv) of the mAb to determine whether the smaller scFv molecule has better binding and functional activity than the intact mAb. The Pembro scFv bound to resting NK cells with a distinct fluorescent peak compared to the native Prembro from which the scFv was derived (Figure 1B). Compared to intact Prembro, use of the Pembro scFv as a PD-1 antagonist resulted in a 2-fold increase of NK cell cytolytic activity and a 3-4 fold increase in cytokine production against the PD-L1 expressing CML target, K562 (Figure 1C-D) and the AML target, THP-1 (Figure 1E-F). While PD-1 blockade enhanced NK cell degranulation and target cell killing, a greater functional enhancement was seen for interferon-γ production. PD-1 signaling inhibits PI3K induced pAkt and NK function. PD-1/PD-1 ligand blockade by the Pembro scFv resulted in increased NK cell pAKT in the presence of PD-L1 and NK activating NKG2D-ligand-expressing THP-1 cells. In addition to natural cytotoxicity, NK-mediated ADCC was also enhanced with PD-1 blockade. CD33 mAb immunoconjugates have been used to treat AML. Combined anti-CD33 mAb and PD-1 blockade against THP-1 cells resulted in a small but significant increase in NK cell degranulation and a 4-fold increase in cytokine production compared to anti-CD33 mAb without PD-1 blockade (Figure 1G-H). Since stimulation with IL-15, a cytokine that effectively lowers the NK activation threshold, abrogated the benefits of Pembro scFv in diminishing PD-1 inhibitory effects on NK cells, PD-1 control of NK function appears limited to be mostly relevant to resting NK cells. To understand the physiologic expression of PD-1 in vivo, we studied samples taken from AML patients receiving matched sibling donor transplantation at the University of Minnesota. Increased PD-1 on reconstituting NK cells in BMT recipients up to day 100 post-transplant was shown by both flow-cytometric (Figure 2A) and mass-cytometric (CyTOF) analyses (Figure 2B). Blockade of PD-1 on these cells significantly enhanced both NK degranulation (Figure 2C) and cytokine production (Figure 2D) against K562 targets. A similar increase in NK function was observed with PD-1 blockade in AML patients receiving umbilical cord transplants (not shown). These data indicate that PD-1 is present on human NK cells and PD-1 ligation negatively regulates NK function against PD-L1 expressing tumor targets. The observation that functional PD-1 is expressed on NK cells under resting conditions strongly suggests that the use of a PD-1 antagonist, in combination with NK cell therapy, should be clinically effective for treatment of cancer. Disclosures Felices: GT Biopharma.: Other: consulting funds, Research Funding. Blazar:Kamon Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Tmunity: Other: Co-Founder; BlueRock Therapeutics: 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; KidsFirst Fund: Research Funding; Childrens' Cancer Research Fund: Research Funding; Leukemia and Lymphoma Society: Research Funding; Abbvie Inc: Research Funding; Alpine Immune Sciences, Inc.: Research Funding; RXi Pharmaceuticals: Research Funding; Fate Therapeutics, Inc.: Research Funding; Magenta Therapeutics and BlueRock Therapeuetics: Membership on an entity's Board of Directors or advisory committees. Vallera:GT Biopharma, Inc.: Consultancy, Research Funding. Miller:Fate Therapeutics, Inc: Consultancy, Research Funding; GT BioPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; CytoSen: Membership on an entity's Board of Directors or advisory committees; OnKImmune: Membership on an entity's Board of Directors or advisory committees; Dr. Reddys Laboratory: Membership on an entity's Board of Directors or advisory committees; Moderna: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Keytruda. PD-1 blockade on NK cells for tumor immunotherapy


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2316-2316
Author(s):  
Bethan Psaila ◽  
Nayla Boulad ◽  
Emily Leven ◽  
Naznin Haq ◽  
Christina Soo Lee ◽  
...  

Abstract The pathogenesis of immune thrombocytopenia (ITP) is multifactorial, with both cellular and humoural immune dysfunction. The role of NK cells has not been well defined in ITP but in other diseases NK cells have a role in rejecting “foreign” eg transplanted organ or tumor, and also acting against self as occurs in autoimmunity. NK cell activity is orchestrated by the balance of activating vs. inhibitory signalling, in particular via the killer cell immunoglobulin-like receptor (KIR) family of receptors. Significant variation exists in KIR allelic subtype and copy number for the KIR between individuals, and associations have been made with certain haplotypes and a number of autoimmune disorders including rheumatoid arthritis, scleroderma and diabetes. Previous reports have demonstrated a reduction in natural killer (NK) cell number and function in ITP and expression of inhibitory KIR genes is increased in patients in remission vs. active ITP. Methods To explore whether a particular KIR haplotype might predispose to ITP, and also affect response to ITP treatment, we performed KIR genotyping using the Invitrogen SSP kit on 92 patients attending a haematology centre in New York and compared the results to data from 213 controls taken from the USA Eastern Database. Genomic DNA was typed for the inhibitory KIR genes KIR2DL1, KIR2DL2, KIR2DL5A (alleles 001 and 002), KIR2DL5B (alleles 002-004, 06, and 007), KIR3DL1, KIR3DL3; the activating KIR genes KIR2DS1, KIR2DS2, KIR2DS3, KIR2DS4, KIR2DS5, KIR3DS1; the framework genes KIR2DL3, KIR2DL4, KIR3DL2, KIR3DP1; and the pseudogene KIR2DP1. The patients with ITP had been or were receiving treatment with IVIG (n=64), corticosteroids (72) and rituximab (37). Bleeding symptoms were recorded. Response to treatment was defined as complete - platelet count increase to > 100 x 109/mL; partial - platelet count increase to > 50 x 109/mL; or no response. For the purpose of analysis, PRs and CRs were combined. A comprehensive database allowed a logistic regression, assessing both responses to treatments, platelet counts, neutrophil counts, CRP, lymphocyte subsets and bleeding symptoms. Results The expression of two inhibitory KIR genes, 2DL1 and 3DL1, was significantly lower in the patients with ITP as compared to controls (87% 2DL1 and 87% 3DL1 compared to 99% in controls - P < 0.02). Response to rituximab was strongly related to KIR haplotype expression. 2DL1 expression was higher among nonresponders to Rituximab (100% of non responders compared to 82% of responders), whereas 2DL3 expression was significantly lower (79% compared to 90%) (P < 0.05, Figure 1B). Separately, patients with the 2DS3 allele, an activatory KIR, were 5.5 times more likely to have experienced significant bleeding. Conclusions Although these findings are preliminary and require further investigation, these data suggest that increased cytotoxic autoimmunity due to reduced KIR inhibition may be associated with the development of ITP and possibly contribute importantly to the pathogenesis. Anti-CD20 targeting therapy directed at B cells was strongly influenced by 2 different KIRs (1 upregulated and one down-regulated) emphasizing the potential role of NK cells in elimination of tissue-based (nodal) B cells. Finally a more pronounced clinical phenotype with a markedly higher incidence of severe bleeding associated with an increased activatory KIR expression demonstrates the role of NK cells in bleeding presumably via their effects on either endothelial cells or platelet function. These exciting findings will be pursued for confirmation in a larger number of patients. Disclosures: Bussel: Amgen: Family owns stock Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Cangene: Research Funding; Genzyme: Research Funding; GlaxoSmithKline: Family owns stock, Family owns stock Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; IgG of America: Research Funding; Immunomedics: Research Funding; Ligand: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Shionogi: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Sysmex: Research Funding; Symphogen: Membership on an entity’s Board of Directors or advisory committees.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 407-407
Author(s):  
Frank Cichocki ◽  
Jode P Goodridge ◽  
Ryan Bjordahl ◽  
Svetlana Gaidarova ◽  
Sajid Mahmood ◽  
...  

Abstract Treatments for B-cell malignancies have improved over the past several decades with clinical application of the CD20-specific antibody rituximab and chimeric antigen receptor (CAR) T cells targeting CD19. Despite the success of these therapies, loss of CD20 after rituximab treatment has been reported in leukemia and lymphoma patients. Additionally, up to 50% of all patients receiving anti-CD19 CAR T-cell therapy relapse within the first year with many of those patients exhibiting CD19 loss. Thus, new therapeutic approaches are needed to address tumor antigen escape. Accordingly, we generated triple gene-modified iPSC-derived NK (iNK) cells, termed "iDuo" NK cells, tailored to facilitate multi-antigen targeting. The iPSC line was clonally engineered to express high-affinity, non-cleavable CD16a (hnCD16), an anti-CD19 CAR optimized for NK cell signaling, and a membrane-bound IL-15/IL-15R fusion (IL-15RF) molecule to enhance NK cell persistence (Fig. 1A). To model antigen escape, we generated CD19 knockout AHR77 lymphoma cells alongside wild type AHR77 cells (both CD20 +) as targets in cytotoxicity assays. Activated peripheral blood NK (PBNK) cells, non-transduced iNK cells, and iDuo NK cells were tested as effectors. Unlike PBNK cells or non-transduced iNK cells, iDuo NK cells efficiently eliminated wild type AHR77 cells with or without the addition of rituximab at all tested E:T ratios. Similarly, iDuo NK cells in combination with rituximab were uniquely able to efficiently eliminate CD19 KO AHR77 cells due to enhanced antibody-dependent cellular cytotoxicity (ADCC) driven by hnCD16 (Fig. 1B-E). Cytotoxicity mediated by iDuo NK cells was also evaluated using primary chronic lymphocytic leukemia (CLL) cells. Compared to expanded PBNK cells and non-transduced iNK cells, only iDuo NK cells (in the absence of rituximab) were able to kill primary CLL cells (Fig. 1F). Expression of IL-15RF by iDuo NK cells uniquely supports in vitro expansion without the need for cytokine supplementation. To determine whether IL-15RF supports in vivo persistence of iDuo NK cells, CD19 CAR iNK cells (lacking IL-15RF) and iDuo NK cells were injected into NSG mice without the addition of cytokines or CD19 antigen availability. iDuo NK cell numbers peaked within a week after injection and persisted at measurable levels for ~5 weeks, in marked contrast to CD19 CAR iNK cell numbers that were undetectable throughout (Fig. 1G). To evaluate the in vivo function of iDuo NK cells, NALM6 leukemia cells were engrafted into NSG mice. Groups of mice received tumor alone or were treated with 3 doses of thawed iDuo NK cells. iDuo NK cells alone were highly effective in this model as evidenced by complete survival of mice in the treatment group (Fig. 1H). To assess iDuo NK cells in a more aggressive model, Raji lymphoma cells were engrafted, and groups of mice received rituximab alone, iDuo NK cells alone, or iDuo NK cells plus rituximab. Mice given the combination of iDuo NK cells and rituximab provided extended survival compared to all other arms in the aggressive disseminated Raji lymphoma xenograft model (Fig. 1I). One disadvantage of anti-CD19 CAR T cells is their inability to discriminate between healthy and malignant B cells. Because NK cells express inhibitory receptors that enable "self" versus "non-self" discrimination, we reasoned that iDuo NK cells could have higher cytotoxicity against tumor cells relative to healthy B cells. To address this, we labeled Raji cells, CD19 + B cells from healthy donor peripheral blood mononuclear cells (PBMCs) and CD19 - PBMCs. Labeled populations of cells were co-cultured with iDuo NK cells, and specific killing was analyzed. As expected, iDuo NK cells did not target CD19 - PBMCs. Intriguingly, iDuo NK cells had much higher cytotoxic activity against Raji cells compared to primary CD19 + B cells, suggesting a preferential targeting of malignant B cells compared to healthy B cells. Together, these results demonstrate the potent multi-antigen targeting capability and in vivo antitumor function of iDuo NK cells. Further, these data suggest that iDuo NK cells may have an additional advantage over anti-CD19 CAR T cells by discriminating between healthy and malignant B cells. The first iDuo NK cell, FT596, is currently being tested in a Phase I clinical trial (NCT04245722) for the treatment of B-cell lymphoma. Figure 1 Figure 1. Disclosures Cichocki: Gamida Cell: Research Funding; Fate Therapeutics, Inc: Patents & Royalties, Research Funding. Bjordahl: Fate Therapeutics: Current Employment. Gaidarova: Fate Therapeutics, Inc: Current Employment. Abujarour: Fate Therapeutics, Inc.: Current Employment. Rogers: Fate Therapeutics, Inc: Current Employment. Huffman: Fate Therapeutics, Inc: Current Employment. Lee: Fate Therapeutics, Inc: Current Employment. Szabo: Fate Therapeutics, Inc: Current Employment. Wong: BMS: Current equity holder in publicly-traded company; Fate Therapeutics, Inc: Current Employment. Cooley: Fate Therapeutics, Inc: Current Employment. Valamehr: Fate Therapeutics, Inc.: Current Employment. Miller: Magenta: Membership on an entity's Board of Directors or advisory committees; ONK Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Vycellix: Consultancy; GT Biopharma: Consultancy, Patents & Royalties, Research Funding; Fate Therapeutics, Inc: Consultancy, Patents & Royalties, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Wugen: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3696-3696
Author(s):  
Konstantinos Christofyllakis ◽  
Frank Neumann ◽  
Stephan Stilgenbauer ◽  
Dominic Kaddu-Mulindwa ◽  
Evi Regitz ◽  
...  

Abstract Introduction: We recently showed that vitamin D deficiency leads to decreased overall survival of DLBCL-patients treated with rituximab-chemotherapy (Bittenbring et al, JCO, 2014). We hypothesized that rituximab-mediated NK cell-cytotoxicity is more effective at higher vitamin D levels. This was confirmed by vitamin D substitution of healthy volunteers, which increased their rituximab-mediated cytotoxicity in vitro against the Daudi lymphoma cell line. To unveil the molecular mechanisms behind this finding, resting NK cells before and after vitamin D supplementation were isolated from those volunteers and a whole transcriptome analysis was performed. Methods: We collected PBMCs from eight healthy volunteers with vitamin D deficiency before and after vitamin D substitution to > 30 ng/ml 25-OH vitamin D3. NK cells were isolated from PBMCs by magnetic depletion of all non-NK cells. Purity of the CD16+ cells was confirmed by flow cytometry. After isolating total RNA, we performed a microarray analysis using an Affymetrix Gene-Chip 2.0 ™. The signals were normalized using the LMA algorithm. For pathway analysis, gene set enrichment analysis (GSEA) was used. A two-step approach was chosen. Firstly, we separated 7.705 genes due to their involvement in the NK cell-mediated immune response according to the Gene Ontology database, irrespective of their differential expression. This dataset was used separately for specific analysis of the NK cell-cytotoxicity pathway to increase sensitivity. Secondly, the complete data set of 48.145 genes was used in an exploratory analysis in an attempt to screen for other dysregulated pathways involved in the immune response and vitamin D homeostasis. We used gene sets provided from the Molecular Signature Database. A significance level of < 0.05 for p and False Discovery Rate (FDR) was chosen. Real-time quantitative PCR was performed to confirm the results. Results: The NK cell-associated cytotoxicity pathway was found to be significantly upregulated after restoration of normal vitamin D levels in the specific analysis. The most significantly overexpressed genes in the gene set were five IFN-α subtypes (IFN-α2, IFN-α4, IFN-α6, IFN-α7, and IFN-α10) as well as IFN-κ. The exploratory analysis showed an upregulation of the response to type I interferon pathway and regulation of type I interferon mediated signaling pathway. The most upregulated genes in those pathways were again the IFN-α subtypes mentioned above. Other pathways involved in the immune response were found to be downregulated after vitamin D substitution, like interferon gamma response; cytokine production and chemotaxis. The common denominator of these pathways was the downregulation of three toll-like receptor genes (TLR-8, TLR-7, TLR-2). Conclusion: The increased expression of specific IFN-α subtypes could explain the increased rituximab-mediated NK cell-cytotoxicity after vitamin D substitution in deficient individuals. To the best of our knowledge, this is the first study to suggest a role for vitamin D in IFN-α regulation. TLRs are known to stimulate cytokine production in NK cells including IFN-α. It can be assumed, that the observed upregulation of IFN-α genes after vitamin D substitution leads to a negative feedback on positive regulators of cytokine production like TLR, causing their downregulation once vitamin D levels are restored. This implies a comprehensive role of vitamin D in IFN-α biosynthesis in human NK cells. Disclosures Stilgenbauer: AbbVie: 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; GSK: 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; Novartis: 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; Janssen: 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; Genentech: 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; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: 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; Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 6-6 ◽  
Author(s):  
Veronika Bachanova ◽  
Joseph Maakaron ◽  
David H. McKenna ◽  
Qing Cao ◽  
Todd E. DeFor ◽  
...  

Background: The innate capacity of natural killer (NK) cells to kill tumor targets has been translated into cancer immunotherapy. GDA-201 is a novel allogeneic NK cell product derived from NK cells from healthy donors, expanded ex-vivo with nicotinamide (NAM) and IL-15. We previously reported improved killing function, in vivo proliferation, organ trafficking, and augmented resistance against exhaustion in pre-clinical models. We conducted a phase 1 study of GDA-201 in combination with monoclonal antibodies to enhance NK cell targeting through antibody-dependent cellular cytotoxicity (ADCC). We now report safety data in patients (pts) with relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) and multiple myeloma (MM), and report efficacy outcomes in pts with NHL. Methods: Following donor apheresis, CD3-depleted mononuclear cells were cultured for 14-16 days with NAM (5mM) and IL-15 (20ng/ml), resulting in a 40-fold increase in NK cells and increased expression of CD62L from 2.9% to 21%. GDA-201 contained ~98% NK cells, and CD3 content was maintained at &lt;0.5% (&lt;5x105/kg/dose). Pts with R/R B-cell NHL or MM received lymphodepleting (LD) therapy with cyclophosphamide (400mg/m2 IV x 3d) and fludarabine (30 mg/m2 /d IV x 3d), followed by GDA-201 (days 0 and 2) and low-dose IL-2 (6 million units sc x 3 doses). Pts with NHL or MM received rituximab (375 mg/m2) or elotuzumab (10 mg/kg), respectively, x 3 weekly infusions. Results: 30 pts were enrolled:15 with NHL and 15 with MM, in 3 cohorts of escalating GDA-201 dose; 15 pts received the maximum target dose (median dose 12.4 [range 2.0-26.0] x 107 cells/kg). There were no dose limiting toxicities. The most common grade 3/4 adverse events were thrombocytopenia (n=9), hypertension (n=5), neutropenia (n=4), febrile neutropenia (n=4), and anemia (n=3). There were no neurotoxic events, confirmed cytokine release syndrome, graft versus host disease, or marrow aplasia. One patient died of E-coli sepsis. In pts with NHL, histologies included diffuse large B cell lymphoma (DLBCL) (de novo n=5, transformed n=3), follicular lymphoma (FL) (n=6), and mantle cell lymphoma (n=1). Median age was 64 (range 48-83 years). Pts had a median of 3 lines of prior therapy (range 1-8); most were multiply relapsed or refractory (n=2), and 87% had advanced stage. Median follow-up was 10.8 months (range 4.3-27.5 months). Ten pts had complete response (CR): 6/6 pts with FL and 4/8 with DLBCL; 1 pt had partial response (PR), and overall response rate in pts with NHL was 73.3%. Median duration of response was 8.7 months (range 4.3-25 months). Flow cytometry confirmed the persistence of GDA-201 in peripheral blood for 7-10 days (range 2-92% donor NK cells on day 7), as well as enhanced in vivo proliferation (median Ki 67 99%). Flow cytometry of biopsied tissues at day 4 demonstrated trafficking to bone marrow and lymph nodes. Four pts underwent re-treatment with GDA-201 without LD chemotherapy; GDA-201 cells were detectable in blood after the re-treatment and likely contributed to deepening of response in 2 patients. Post-GDA-201 therapy included allogeneic (n=2) and autologous (n=1) hematopoietic stem cell transplantation. One-year estimates of progression-free survival and overall survival were 66% (95% CI 36-84%) and 82% (95% CI 42-95%), respectively. Conclusions: Cellular therapy using GDA-201 with monoclonal antibodies to enhance ADCC was well-tolerated, and demonstrated significant clinical activity in heavily pretreated pts with advanced NHL. Data support the future testing of multiple infusions to potentially enhance anti-tumor effect. The omission of lymphodepleting chemotherapy is feasible and contributes to safety of this approach. Phase II studies in aggressive and indolent NHL cohorts are planned. Disclosures Bachanova: Incyte: Research Funding; FATE: Research Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Karyopharma: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Gamida Cell: Membership on an entity's Board of Directors or advisory committees, Research Funding. McKenna:Gamida: Other: Cell Manufacturing; Fate Therapeutics: Other: Cell Manufacturing; Intima: Other: Cell Manufacturing; Magenta: Other: Cell Manufacturing. Janakiram:Takeda, Fate, Nektar: Research Funding. Simantov:Gamida Cell: Current Employment. Lodie:Gamida Cell: Current Employment. Miller:Vycellix: Consultancy; Nektar: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onkimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; GT Biopharma: Consultancy, Patents & Royalties, Research Funding; Fate Therapeutics, Inc: Consultancy, Patents & Royalties, Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 138-138
Author(s):  
John Daly ◽  
Subhashis Sarkar ◽  
Alessandro Natoni ◽  
Robert Henderson ◽  
Dawn Swan ◽  
...  

Introduction: Evading Natural Killer (NK) cell-mediated immunosurveillance is key to the development of Multiple Myeloma (MM). Recent attention has focused on the role of hypersialylation in facilitating immune-evasion of NK cells. Abnormal cell surface sialylation is considered a hallmark of cancer and we have implicated hypersialylation in MM disease progression. Certain sialylated glycans can act as ligands for the sialic acid-binding immunoglobulin-like lectin (Siglec) receptors expressed by NK cells (Siglec-7 and Siglec-9). These ITIM motif-containing inhibitory receptors transmit an inhibitory signal upon sialic acid engagement. We hypothesized that desialylation of MM cells or targeted interruption of Siglec expression could lead to enhanced NK cell mediated cytotoxicity of MM cells. Methodology: MM cells were treated with the sialidase neuraminidase prior to co-culture with primary NK (PNK) cells. MM cells were treated with 300µM 3Fax-Neu5Ac (sialyltransferase inhibitor) for 3 days prior to co-cultures with PNK cells. PNK cells were expanded, IL-2 activated (500U/ml) overnight, or naïve (resting). Primary MM samples/MM cell lines were screened with Siglec-7/9 chimeras (10µg/ml). PNK (IL-2 activated) cells were stained with anti-Siglec-7 and anti-Siglec-9 antibodies. Siglec-7 was targeted for knockout (KO) using the CRISPR/Cas9 system, a pre-designed guideRNA and the MaxCyteGT transfection system. MM cells were treated with 10µg/ml of Daratumumab prior to co-culture with expanded PNK cells. Results: Using recombinant Siglec-7/9 chimeras a panel of MM cell lines (MM1S, RPMI-8226, H929, JJN3 and U266) were shown to express ligands for Siglec-7 and Siglec-9 (&gt;85%, n=3). Primary MM cells isolated from BM of newly diagnosed (n=3) and relapsed patients (n=2) were also shown to express Siglec-7 ligands (72.5±17.5%, 36.5% respectively). PNK cells express Siglec-7 and Siglec-9 (94.3±3.3% and 61±8.8% respectively, n=6). Desialylation of the MM cell lines JJN3 and H929 using neuraminidase significantly enhanced killing of MM cells by healthy donor (HD) derived PNK cells (expanded, IL-2 activated and naïve, n=7) at multiple effector:target (E:T) cell ratios. Furthermore, de-sialylation of JJN3 and H929 using neuraminidase resulted in increased NK cell degranulation (CD107α expression), compared to a glycobuffer control (n=7). De-sialylation, using 300µM 3Fax-Neu5Ac, resulted in strongly enhanced killing of MM1S by expanded HD-derived PNK cells at multiple E:T ratios (n=5, p&lt;0.01 at 0.5:1, p&lt;0.001 at 1:1, p&lt;0.01 at 2.5:1). Furthermore, CD38 expression on H929 MM cells significantly increased after treatment with 300µM 3Fax-Neu5Ac for 3 days (p&lt;0.01, n=3). In a cytotoxicity assay, expanded PNK cell-mediated antibody dependent cellular cytotoxicity (ADCC) of H929 MM cells pre-treated with Daratumumab (anti-CD38 moAb) and 3Fax-Neu5Ac was significantly higher than H929 cells pre-treated with Dara (p&lt;0.05 at 0.5:1, p&lt;0.01 at 1:1) or 3Fax-Neu5Ac (p&lt;0.01 at 0.5:1, p&lt;0.01 at 1:1) alone (n=5). Using CRISPR/Cas9, over 50% complete KO of Siglec-7 was observed on expanded PNK cells, yet did not result in enhanced NK cell-mediated cytotoxicity against either H929 or JJN3 (n=7). Siglec-9 KO using CRISPR/Cas9 is ongoing. Discussion: Hypersialylation of MM cells facilitates immune evasion and targeted removal of sialic acid strongly enhances the cytotoxicity of NK cells against MM. However, to date the role of Siglecs remains inconclusive. Nevertheless, our data suggest that targeted desialylation is a novel therapeutic strategy worth exploring in MM. In particular, upregulation of CD38 provides a strong rationale for combinatory strategies employing targeted desialylation with CD38 moAbs such as Daratumumab, with the goal of maximizing ADCC. Disclosures Sarkar: Onkimmune: Research Funding. O'Dwyer:Onkimmune: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; GlycoMimetics Inc: Research Funding; AbbVie: Consultancy.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3186-3186
Author(s):  
Anna Kalff ◽  
Tiffany Khong ◽  
Malarmathy Ramachandran ◽  
Sam Norton ◽  
Andrew Mitchell ◽  
...  

The ALLG MM14 trial evaluated the impact of low dose dexamethasone (LoDEX) withdrawal in lenalidomide (LEN) refractory and relapsed (RR) multiple myeloma (MM) patients achieving initial disease control with pomalidomide (POM) and LoDEX re-induction. As previously reported, patients continuing with POM LoDEX had superior progression free survival (PFS) compared to maintenance with POM alone, however, this early PFS benefit was lost and by 18m was reversed to favour POM only. In patients who received post-progression therapy, more durable responses (second PFS: 12.7m vs 4.6m, p=0.034) and superior survival (OS: 19.4m vs 12.5m, p=0.092) were seen in those previously treated with POM alone. Here we present findings from the preliminary correlative immune studies of this trial. Aims To undertake mass cytometry (CyTOF) based immune profiling in patients with advanced MM receiving treatment with POM LoDEX. Methods MM14 was a multicentre, open-label, randomised phase 2 study of LEN refractory RRMM patients who had received ≥ 2 prior lines of therapy. Patients were treated with POM 4mg d1-21 (28d cycle) and LoDEX (40mg weekly). After 4 cycles (induction), patients with stable disease or better (≥SD) were randomised to receive maintenance with ongoing POM-LoDEX or POM alone. Therapy continued until toxicity/progression. PBMCs were collected at baseline and sequentially while on treatment. Cells were barcoded using the Cell-ID 20-Plex Pd barcoding kit (Fluidigm) followed by staining with sub-set/function defining antibodies (targeting myeloid, B, T and NK cells: CD16, CD24, CD11c, CD45RO, CD314, CD38, CD336, HLA-DR, CD14, CD56, CD158a, CD27, CD28, CD159a, CD8, CD19, CD45RA, CD11b, CD4, IgD, CD335, FOXP3, CD25, CD66b, CD3, CD337, CD20, CD158b, CD127 CD57, CD197, CD194, CD304 and CD279). Samples were acquired on the Helios instrument. Data were clustered in the VORTEX package. Significant differences in cluster frequency were assessed by Mann-Whitney test for statistical significance. Cluster phenotypes were determined and validated via multiple visualisation approaches. CD3-CD19-CD56+ NK cells were pre-gated from patient datasets. We then performed Boolean gating using seven NK cell activation/inhibitory markers - CD158a, CD158b, CD159a, CD314, CD335, CD336 and CD337. Boolean populations that comprised 3% or greater of the total NK cell population (median) were then compared. A Mann-Whitney test was used to determine statistical significance. Results 154 patients from 11 Australian sites were enrolled. The median number of prior treatment lines was 4.5, 82.5% were double refractory. 78 patients who achieved ≥SD were randomised to maintenance: POM n = 40, Pom LoDEX n = 38. CD336+CD20+ cells ("NK-B-cells") were identified in the pre-induction samples of all patients and were significantly more frequent in responders (median 2% of total cells) than in non-responders (0.8% of total cells, p<0.0001). These cells also variably expressed CD19, IgD, HLA-DR, CD158b, CD38 and CD45RA. Preliminary validation of this observation has also been successfully undertaken in an independent cohort of MM patients utilising multi-parameter flow cytometry. In the patients who achieved ≥SD, 5 out of the 8 large clusters (each at least 3% [median] of total nucleated cells evaluated) that were significantly enriched (p<0.0001) following POM LoDEX induction were neutrophil populations. These populations all expressed CD66b but with variable expression of CD24, CD16, CD11c, CD11b and CD45RO. Inhibited NK cells (CD3-CD19-CD56+) based on CD159a, CD314 and CD158a expression were enriched pre-induction and significantly decreased following POM LoDEX (p<0.0001), while activated NK cells expressing CD337 and CD336 and no inhibitory receptors were significantly increased following POM LoDEX (p<0.0001). Conclusion Utilising CyToF, we have identified a novel "NK B cell" population in RRMM patients, with a higher baseline frequency of these cells being associated with a greater likelihood of response to POM LoDEX. Importantly, we have also confirmed the presence of these cells in an independent MM cohort. Moreover, subsequent to POM LoDEX exposure we have demonstrated the enrichment of heterogeneous neutrophil populations as well as an increase in activated NK cells and commensurate decrease in inhibited NK cells. These novel observations may provide new insights into the mechanisms of action of pomalidomide in MM. Disclosures Kalff: Amgen: Honoraria; Celgene: Honoraria; pfizer: Honoraria. Khong:Novartis Oncology: Research Funding. Reynolds:Alfred Health: Employment, Other: Biostatistician for trials funded by the Australian government and Abbvie, Amgen, Celgene, GSK, Janssen-Cilag, Merck, Novartis, Takeda, but sponsored by Alfred Health.; AUSTRALASIAN LEUKAEMIA & LYMPHOMA GROUP (ALLG): Consultancy; Novartis AG: Equity Ownership; Novartis Australia: Honoraria. Quach:GSK: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees. Ho:Novartis: Other: Trial Investigator meeting travel costs; La Jolla: Other: Trial Investigator meeting travel costs; Celgene: Other: Trial Investigator meeting travel costs; Janssen: Other: Trial Investigator meeting travel costs. Mollee:Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spencer:Takeda: Other: Consulting/advisory role, Research Funding; Janssen Oncology: Other: Consulting/advisory role, Research Funding, Speakers Bureau; Amgen: Other: Consulting/advisory role, Research Funding; AbbVie: Other: Consulting/advisory role, Research Funding; Servier: Other: Consulting/advisory role; Secura Bio: Other: Consulting/advisory role; Haemalogix: Other: Consulting/advisory role; Celgene: Other: Consulting/advisory role, Research Funding, Speakers Bureau; Sanofi: Other: Consulting/advisory role; Specialised Therapeutics Australia: Consultancy, Honoraria.


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