Rejuvenated BCMA-Specific CD8 + Cytotoxic T Lymphocytes Derived from Antigen-Specific Induced Pluripotent Stem Cells : Immunotherapeutic Application in Multiple Myeloma

Abstract T cell regenerative medicine represents an emerging immunotherapeutic approach using antigen-specific Induced Pluripotent Stem Cells (iPSC) to rejuvenate CD8 + cytotoxic T lymphocytes (CTL). Here we report on an iPSC-derived therapeutic strategy targeting B-Cell Maturation Antigen (BCMA) against multiple myeloma (MM) via establishment of antigen-specific iPSC, followed by differentiation into highly functional BCMA-specific CD8 + CTL. The reprogrammed BCMA-specific iPSC displayed normal karyotypes and pluripotency potential as evidenced by expression of stem cell markers (SSEA-4, TRA1-60) and alkaline phosphatase, along with differentiation into three germ layers (Ectoderm, Mesoderm, Endoderm). During embryoid body formation, BCMA-specific iPSC further polarized into the mesoderm germ layer, evidenced by the activation of SNAI2, TBX3, PLVAP, HAND1 and CDX2 transcriptional regulators. Next, the BCMA-specific iPSC clones committed to CD8 + T cell differentiation were characterized by analyzing their hematopoietic progenitor cells (HPC; CD34 + CD43 +/CD14 - CD235a -) for specific transcriptional regulation. RNAseq analyses indicated a low variability and similar profiles of gene transcription within the iPSC clones committed to CD8 + CTL compared to increased transcriptional variability within iPSC clones committed to different cell types. The unique transcriptional profiles of the iPSC committed to CD8 + T cells included upregulation of transcriptional regulators controlling CD4/CD8 T cell differentiation ratio, memory CTL formation, NF-kappa-B/JNK pathway activation, and cytokine transporter/cytotoxic mediator development, as well as downregulation of regulators controlling B and T cell interactions, CD4 + Th cells, and inhibitory receptor development. Specifically, a major regulatory shift, indicated by upregulation of specific genes involved in immune function, was detected in HPC from the iPSC committed to CD8 + T cells. BCMA-specific T cells differentiated from the iPSC were characterized as displaying mature CTL phenotypes including high expression of CD3, CD8a, CD8b, TCRab, CD7 along with no CD4 expression (Fig. 1). In addition, the final BCMA iPSC-T cells were predominantly CD45RO + memory cells (central memory and effector memory cells) expressing high level of T cell activation (CD38, CD69) and costimulatory (CD28) molecules. Importantly, these BCMA iPSC-T cells lacked immune checkpoints (CTLA4, PD1, LAG3, Tim3) expression and regulatory T cells induction, distinct from other antigen-stimulated T cells. The rejuvenated BCMA iPSC-T cells demonstrated a high proliferative (1,000 folds increase) during the differentiation process as well as poly-functional anti-tumor activities and Th1 cytokine (IFN-g, IL-2, TNF-a) production triggered in response to MM patients' cells in HLA-A2-restricted manner (Fig. 2). Furthermore, the immune responses induced by these BCMA iPSC-T cells were specific to the parent heteroclitic BCMA 72-80 (YLMFLLRKI) peptide used to reprogram and establish the antigen-specific iPSC. Evaluation of 88 single cell Tetramer + CTL from the BCMA iPSC-T cells revealed a clonotype of unique T cell receptor (TCRa, TCRb) sequence. The BCMA-specific iPSC clones maintained their specific differentiation potential into the antigen-specific CD8 + memory T cells, following multiple subcloning in long-term cultures under feeder-free conditions or post-thaw after long-term (18 months) cryopreservation at -140 oC, which provides additional benefits to treat patients in a continuous manner. Taken together, rejuvenated CD8 + CTL differentiated from BCMA-specific iPSC were highly functional with significant (*p < 0.05) levels of anti-MM activities including proliferation, cytotoxic activity and Th-1 cytokine production. Therefore, the antigen-specific iPSC reprogramming and T cells rejuvenation process can provide an effective and long-term source of antigen-specific memory CTL lacking immune checkpoints and suppressors for clinical application in adoptive immunotherapy to improve patient outcome in MM. Figure 1 Figure 1. Disclosures Munshi: Amgen: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; Adaptive Biotechnology: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy; Abbvie: Consultancy; Janssen: Consultancy; Legend: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Novartis: Consultancy; Pfizer: Consultancy. Ritz: Amgen: Research Funding; Equillium: Research Funding; Kite/Gilead: Research Funding; Avrobio: Membership on an entity's Board of Directors or advisory committees; Akron: Consultancy; Biotech: Consultancy; Blackstone Life Sciences Advisor: Consultancy; Clade Therapeutics, Garuda Therapeutics: Consultancy; Immunitas Therapeutic: Consultancy; LifeVault Bio: Consultancy; Novartis: Consultancy; Rheos Medicines: Consultancy; Talaris Therapeutics: Consultancy; TScan Therapeutics: Consultancy. Anderson: Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: 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; Celgene: 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.

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The Tumor Microenvironment of Nodular Lymphocyte Predominant Hodgkin Lymphoma Is a Unique Immunobiological Entity Distinct from Classical Hodgkin Lymphoma

Blood ◽

10.1182/blood-2018-99-115836 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4123-4123

Author(s):

Jay Gunawardana ◽

Karolina Bednarska ◽

Soi C Law ◽

Justina Lee ◽

Muhammed Bilal Sabdia ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Hodgkin Lymphoma ◽

Research Funding ◽

Host Immunity ◽

Immune Checkpoints ◽

Classical Hodgkin Lymphoma ◽

Advisory Committees ◽

Immune Effector

Abstract There is proven pre-clinical and clinical efficacy of mono or combinatorial immune strategies to boost host anti-lymphoma immunity, with classical Hodgkin Lymphoma (cHL) seen as the 'poster child'. Approaches include blockade of immune-checkpoints on exhausted tumor-specific T-cells (via mAb blockade of PD-1, TIM3, LAG3, TIGIT or their ligands), activation of T-cells via mAbs agonistic to CD137, and finally modulation of FOXP3, CTLA-4 and/or LAG3 regulatory T-cells (Tregs) or immunosuppressive tumor-associated macrophages (TAMs). In contrast, studies characterizing the circulating and intra-tumoral microenvironment (TME) of the distinct but rare CD20+ Hodgkin Lymphoma entity (5-8% of HL), Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL), are minimal. Furthermore, to our knowledge no functional profiling studies comparing the host immunity of NLPHL with cHL has been performed. We compared host immunity in 29 NLPHL patients, 30 cHL patients and 10 healthy individuals, with a focus on pertinent and clinically actionable immune parameters. Paraffin-embedded tissue and paired (pre- and post-therapy) peripheral blood mononuclear cells samples were interrogated by digital multiplex hybridization (Nanostring Cancer Immune Profiling Panel) and flow cytometry. Although cytotoxic T-cell gene counts (CD8a, CD8b) were similar, compared to cHL there were higher levels of the immune effector activation marker CD137 (gene counts 439 vs. 287; P<0.01). Consistent with this, CD4 and the Treg markers LAG3, FOXP3 and CTLA-4 were lower in NLPHL (2-4 fold lower, all P<0.05), with no difference in T-helper cell activation markers CD40L and CD30L seen between tumors. TAMs and dendritic cell markers MARCO, CD36, CD68, CD163, COLEC12 and CD11b were all lower in NLPHL than cHL (all P<0.05). In line with the known 'rossette' formed around LP cells by PD-1+ T-lymphocytes, we observed strikingly elevated PD-1 and the other T-cell checkpoints TIM3 and TIGIT in NLPHL (all 2-3 fold, P<0.001). However, in line with the known gene amplification of PD-L1 on HRS cells and its presence on TAMs, gene counts of this checkpoint ligand were 2-fold higher in cHL (P<0.001). Flow cytometry profiling of immune subsets in peripheral blood showed findings consistent with findings in the TME. Specifically, there was elevation of multiple exhaustion markers within CD4, CD8, and NK immune effector cells, with a striking proportion of highly anergic dual-LAG3/PD-1 positive CD8+ T-cells. Also there was elevation of immune-suppressive monocyte/macrophages in cHL relative to NLPHL. Relative to healthy lymph nodes, there was prominent up-regulation of a range of T-cell associated exhaustion markers in both NLPHL and cHL, indicating dysregulated priming of effector immune responses and host immune homeostasis. Comparison between NLPHL and cHL illustrated that NLPHL had a myriad of features that marked its intratumoral TME as a unique immunobiological entity typified by elevated immune checkpoint markers and T-cells with a highly anergic phenotype. Put together, these findings indicate that distinct immune evasion mechanisms are operative within the TME of NLPHL, including markedly higher levels of multiple immune-checkpoints relative to cHL. In contrast, Treg subsets and immune-suppressive monocyte/macrophages were relatively lower than that seen in cHL. T-cells frequently had dual immune-checkpoint expression. The findings from this study provides a compelling pre-clinical rationale for targeting PD-1 or combinatory checkpoint inhibition in NLPHL and sets the basis for future 'chemo-free' rituximab + checkpoint inhibitor clinical trials. Disclosures Tobin: Amgen: Other: Educational Travel; Celgene: Research Funding. Birch:Medadvance: Equity Ownership. Keane:Takeda: Other: Educational Meeting; BMS: Research Funding; Roche: Other: Education Support, Speakers Bureau; Celgene: Consultancy, Research Funding; Merck: Consultancy. Gandhi:BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Takeda: Honoraria; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Phase 1 Study of CD19 Targeted 4-1BBL Costimulatory Agonist to Enhance T Cell (Glofitamab Combination) or NK Cell Effector Function (Obinutuzumab Combination) in Relapsed/Refractory B Cell Lymphoma

Blood ◽

10.1182/blood-2020-136571 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 16-17 ◽

Cited By ~ 1

Author(s):

Martin Hutchings ◽

Fritz C. Offner ◽

Francesc Bosch ◽

Giuseppe Gritti ◽

Carmelo Carlo-Stella ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Dose Escalation ◽

Research Funding ◽

Bispecific Antibody ◽

Nk Cell ◽

Publicly Traded ◽

Advisory Committees ◽

Anti Tumor Activity

Background: Up to 50% of patients suffering from Non-Hodgkin`s lymphoma (NHL) become refractory to or relapse after treatment (M. Crump, Blood 2017). With this, the lack of curative outcomes for patients with both indolent and aggressive NHL subtypes remains an unmet medical need. The CD20 CD3 T cell bispecific antibody glofitamab induces specific T-cell activation and has demonstrated significant single agent activity in r/r NHL patients (NP30179 study, M. Dickinson, EHA 2020, Abstract S241). RO7227166, a CD19 targeted 4-1BBL (CD137) costimulatory agonist has shown synergistic anti-tumor activity when combined with glofitamab in preclinical models (fig 1). RO7227166 is a bispecific antibody-like fusion protein composed of a split trimeric 4-1BB ligand, a tumor antigen-targeting moiety recognizing CD19, and a silent Fc part preventing Fc-mediated toxicity. 4-1BB is an inducible co-stimulatory molecule expressed by activated T-cells or NK cells. Through CD19-binding, the 4-1BB ligand moiety can deliver co-stimulatory signals to activated T- and NK-cell subsets in the tumor. The expected mode of action (MoA) for this molecule is to deliver a costimulatory signal 2 to enhance the effector function of tumor-infiltrating T cells or NK cells upon their activation (signal 1) by a T-cell bispecific antibody (e.g. glofitamab, RO7082859) or a tumor-targeted ADCC antibody (e.g. obinutuzumab). By delivering direct T-cell-target cell engagement followed by costimulatory activation the aim is to offer a highly active off-the-shelf immunotherapy combination. Methods: RO7227166 is being developed in combination with glofitamab and obinutuzumab in a phase I, open-label, dose-escalation study BP41072 (NCT04077723). The study is designed to evaluate the combination maximum tolerated dose (MTD), safety, tolerability, pharmacokinetic (PK), and/or pharmacodynamic (PD) profile of escalating doses of RO7227166, and to evaluate preliminary anti-tumor activity in participants with r/r NHL. The dose escalation stage is divided into Part I (combination with obinutuzumab) and Part II (combination with glofitamab) followed by an expansion stage (Part III). During Part I patients receive 1000mg obinutuzumab intravenously (IV) at a q3w schedule in combination with CD19 4-1BBL IV. During part II glofitamab is given in a q3w schedule with RO7227166 introduced at C2D8 and administered concomitantly from C3D1 onwards. A fixed dose of obinutuzumab (Gpt; pre-treatment) is administered seven days prior to the first administration of RO7227166 and seven days prior to the first administration of glofitamab (M. Bacac, Clin Cancer Res 2018; M. Dickinson, EHA 2020, Abstract S241). Patients will initially be recruited into part I of the study only using single-participant cohorts, where a rule-based dose-escalation is implemented, with dosing initiated at 5 μg (flat dose). As doses of RO7227166 increase, multiple participant cohorts will be recruited and dose-escalation will be guided by the mCRM-EWOC design for overdose control. Commencement of Part II including decision on the RO7227166 starting dose will be guided by safety and PK data from Part I. Patients with r/r NHL meeting standard organ function criteria and with adequate blood counts will be eligible. The maximum duration of the study for each participant will be up to 24 months in Part I (excluding survival follow-up) and up to 18 months in Part II and Part III. Tumor biopsies and peripheral blood biomarker analyses will be used to demonstrate MoA and proof of concept of an off the shelf flexible combination option providing signals 1 and 2. Disclosures Hutchings: Takeda: Honoraria; Takeda: Research Funding; Genmab: Honoraria; Roche: Honoraria; Genmab: Research Funding; Janssen: Research Funding; Novartis: Research Funding; Sankyo: Research Funding; Roche: Consultancy; Genmab: Consultancy; Takeda: Consultancy; Roche: Research Funding; Celgene: Research Funding; Daiichi: Research Funding; Sanofi: Research Funding. Bosch:Hoffmann-La Roche: Research Funding. Gritti:Italfarmaco: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria; Jannsen: Other: Travel Support; Autolus: Consultancy; IQVIA: Consultancy; Kite: Consultancy; Takeda: Honoraria; Amgen: Honoraria. Carlo-Stella:Bristol-Myers Squibb, Merck Sharp & Dohme, Janssen Oncology, AstraZeneca: Honoraria; Servier, Novartis, Genenta Science srl, ADC Therapeutics, F. Hoffmann-La Roche, Karyopharm, Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics and Rhizen Pharmaceuticals: Research Funding; Boehringer Ingelheim and Sanofi: Consultancy. Townsend:Roche, Gilead: Consultancy, Honoraria. Morschhauser:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Consultancy; Janssen: Honoraria; Epizyme: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy. Cartron:Celgene: Consultancy, Honoraria; F. Hoffmann-La Roche: Consultancy, Honoraria; Sanofi: Honoraria; Abbvie: Honoraria; Jansen: Honoraria; Gilead: Honoraria. Ghesquieres:CELGENE: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Roche: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Janssen: Honoraria. de Guibert:Gilead Sciences: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Herter:Roche Glycart AG: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties. Korfi:Roche Diagnostics GmbH: Consultancy. Craine:Roche: Current Employment. Mycroft:Roche: Current Employment. Whayman:Roche: Current Employment. Mueller:Roche: Current Employment. Dimier:Roche: Current Employment. Moore:Roche: Current Employment. Belli:Roche Pharma: Current Employment. Kornacker:Hoffmann-La Roche Ltd.: Current Employment, Current equity holder in publicly-traded company. Lechner:Roche Diagnostics GmbH: Current Employment, Current equity holder in publicly-traded company. Dickinson:Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck Sharp & Dohme: Consultancy; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

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Peri-Transplant Alemtuzumab Levels Predict Risk of Secondary Graft Failure and Inversely Impact CXCL9 Levels after RIC HCT (A Correlative Biology Study to BMT-CTN 1204 RICHI)

Blood ◽

10.1182/blood-2021-145629 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 748-748

Author(s):

Ashley V Geerlinks ◽

Brooks Scull ◽

Christa Krupski ◽

Ryan Fleischmann ◽

Michael A. Pulsipher ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Interferon Gamma ◽

Research Funding ◽

Graft Failure ◽

Mixed Chimerism ◽

Publicly Traded ◽

Advisory Committees ◽

Donor Chimerism

Abstract Introduction The BMT-CTN 1204 study for Hemophagocytic Syndromes or Selected Primary Immune Deficiencies (NCT01998633) (RICHI) was a single arm study testing safety and efficacy of reduced intensity conditioning (RIC) with alemtuzumab (1mg/kg), fludarabine (150 mg/m2) and melphalan (140 mg/m2). Survival was favorable compared to historical studies, but patients experienced high rates of mixed chimerism (MC) and ultimate secondary graft failure (GF). Mechanisms for GF are not known. Expansion of recipient T cells and interferon-gamma pathway activation have been proposed as drivers for GF. However, high peri-transplant alemtuzumab levels have been associated with higher risk of MC and eventual secondary GF, suggesting an inverse relationship between GF and immune activation in the context of RIC. In order to elucidate mechanisms of GF for patients on the RICHI study, we systematically evaluated cytokine patterns and alemtuzumab levels and their association with durable engraftment. Methods Serial blood samples were collected, processed, and stored for consenting patients at day -14 (window: day -28 to -14), day -7 (+/- 1 day), day -1 (+/- 1), day +1 (+1 to +3), day +14 (+/- 2), day +28 (+/- 2), day +42 (+/- 3), day +70 (+/- 10), and day +100 (+/- 10). Alemtuzumab levels were measured using a flow cytometric assay as previously described. Comprehensive cytokine analysis was performed for over 100 analytes using the MagPix platform. Primary GF was defined as donor chimerism <5% prior to day +42. Secondary GF was defined as donor chimerism <5% after initial engraftment and/or requirement of donor lymphocyte infusion (DLI) or second HCT (with or without conditioning) to manage MC or graft loss. Mixed chimerism (MC) was defined as donor chimerism <95% on at least one occasion. Results Thirty-three patients were included in this study with HLH (n=25), CAEBV (n=3), CGD (n=2), HIGM (n=2), and IPEX (n=1). All patients received bone marrow grafts and 27 (82%) patients had unrelated donors. Twenty-one grafts were 8/8 or 6/6 HLA-matched (64%) and 12 grafts were 7/8 HLA-matched (36%). Among all patients, 1 patient (3%) developed primary GF, 22 (67%) developed mixed chimerism (MC), and 11 patients (33%) developed secondary GF. Survival with sustained engraftment without DLI or second HCT was 40.0%. We first evaluated peripheral blood levels of 100+ cytokines. Analysis revealed significant differences between patients with and without GF as shown in Figure 1A. Notably, on day +14 and +28, patients with secondary GF had significantly lower CXCL9 levels than those without GF. We then estimated the cumulative incidence (CI) of secondary GF among patients with CXCL9 levels above and below the day +14 median level of 2394pg/mL. The CI of secondary GF in patients with a day +14 CXCL9 level ≤2394pg/mL was 73.6% vs 0% in patients with a level >2394pg/mL (p=0.002). The CI of secondary GF in patients with a day +28 CXCL9 level ≤2867pg/mL (day +28 median) was 64.3%, vs 0% in patients with levels >2867pg/mL (p=0.004). We then sought to correlate CXCL9 levels with alemtuzumab exposure, as high alemtuzumab levels would result in more efficient T cell depletion of donor grafts that could lead to lower CXCL9 levels. Indeed, CXCL9 levels inversely correlated with day 0 alemtuzumab levels. Patients with day 0 alemtuzumab levels >0.32µg/mL had lower CXCL9 levels compared to patients with levels ≤0.32µg/mL (Figure 1B). Finally, we examined the impact of alemtuzumab levels on MC and secondary GF. Patients with day 0 alemtuzumab levels ≤0.32µg/mL had a lower CI of MC compared to patients with levels >0.32µg/mL, 14.3% vs 90.9%, respectively (p=0.03). The CI of secondary GF was 0% in patients with day 0 alemtuzumab levels ≤0.32µg/mL compared to 54.3% in patients with levels >0.32µg/mL (p=0.08). Conclusions This study demonstrates a strong relationship between alemtuzumab levels and durable engraftment. Further, interferon gamma activity, as reflected by CXCL9, inversely correlates with peri-transplant alemtuzumab levels in this prospective cohort treated with RIC. Our findings support the paradigm that higher alemtuzumab levels drive efficient T cell depletion of the stem cell product which increases the risk of MC and secondary GF, suggesting that donor T cells promote engraftment via a graft versus hematopoiesis function. Precision alemtuzumab dosing strategies may offer an opportunity to improve outcomes for patients who undergo RIC HCT. Figure 1 Figure 1. Disclosures Pulsipher: Adaptive: Research Funding; Equillium: Membership on an entity's Board of Directors or advisory committees; Jasper Therapeutics: Honoraria. Bollard: Neximmune: Current equity holder in publicly-traded company; Catamaran Bio: Membership on an entity's Board of Directors or advisory committees; Cabaletta Bio: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Mana Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Cellectis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Repertoire Immune Medicines: Current equity holder in publicly-traded company; ROCHE: Consultancy, Honoraria; SOBI: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kean: Regeneron: Research Funding; Bristol Myers Squibb: Patents & Royalties: From clinical trial data, Research Funding; Bluebird Bio: Research Funding; Gilead: Research Funding; Vertex: Consultancy; Novartis: Consultancy; EMD Serono: Consultancy. Jordan: Sobi: Consultancy. Allen: Sobi: Consultancy. OffLabel Disclosure: Alemtuzumab, humanized monoclonal antibody against CD52, used as part of allogeneic HCT conditioning

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A Bank of CD30.CAR-Modified, Epstein-Barr Virus-Specific T Cells That Lacks Host Reactivity and Resists Graft Rejection for Patients with CD30-Positive Lymphoma

Blood ◽

10.1182/blood-2020-141491 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 16-16

Author(s):

David H. Quach ◽

Haran R. Ganesh ◽

Sachin Thakkar ◽

Luis Becerra-Dominguez ◽

Birju Mehta ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Graft Rejection ◽

Research Funding ◽

Publicly Traded ◽

Advisory Committees ◽

T Cell Therapy ◽

Barr Virus ◽

Alloreactive T Cells

While autologous T cell therapies can effectively treat B-cell leukemia and lymphoma, the personalized manufacturing process is difficult to scale, expensive and may fail. Even when autologous products are successfully manufactured, they are not immediately available to acutely ill patients. "Off-the-shelf" T cell products derived from healthy donors that can rapidly be administered, would improve accessibility and reduce the cost of T cell therapy. However, major obstacles to successful allogeneic T cell products include their potential for graft-versus-host disease (GVHD) and graft rejection, mediated by host and recipient alloreactive T cells respectively. To address GVHD, we are using Epstein-Barr Virus-specific T cells (EBVSTs) as our platform since they are virus specific rather than allospecific and have not produced GVHD in more than 300 allogeneic recipients. To prevent graft rejection we have introduced into these EBVSTs, a chimeric antigen receptor for CD30 (CD30.CAR). CD30 is upregulated during the activation of alloreactive T cells, which leads to them becoming targets. The CD30.CAR provides the additional advantage of targeting CD30-positive lymphoma and has proved safe and effective in prior clinical trials (NCT02917083) using autologous CAR-T cells. Hence, we expect off-the-shelf CD30.CAR EBVSTs to eliminate the alloreactive T cells they elicit in allogeneic hosts, and therefore persist for sufficient time to eliminate CD30-positive lymphoma, without causing GVHD. Here we show that CD30.CAR-EBVSTs resist fratricide by masking their own CD30 molecules expressed in cis, but are nonetheless protected from rejection when co-cultured with alloreactive T cells expressing CD30 in trans. Notably, CD30.CAR EBVSTs preserve the function of both their TCR and the CD30.CAR, with retention of EBV specificity and the ability to eliminate CD30-positive tumor cells. We have manufactured a bank of clinical grade CD30.CAR EBVSTs from donors with HLA types designed to provide a partial HLA match for our diverse recipients. Clinical grade CD30.CAR EBVST cultures readily expanded to sufficient numbers for a planned clinical trial and expressed the CD30.CAR on 77% to 99% of cells. All of the lines passed functional release criteria of having greater than 100 IFNɣ spot-forming units (SFU) per 105 cells in response to both latent and lytic EBV antigens, and greater than 20% specific cytolysis against a CD30-positive Hodgkin lymphoma cell line, HDLM2, at an effector to target ratio of 20:1. Although CD30.CAR killing is not HLA restricted, we will select the CD30.CAR EBVST product for each recipient, based on the best HLA class I and class II match. This will allow endogenous EBV to boost the in vivo activity of CD30.CAR EBVSTs, and will provide additional reactivity for patients with CD30-positive and EBV-positive tumors. The IND for the clinical trial (NCT04288726) has been approved and we will recruit patients with CD30-positive lymphomas including Hodgkin lymphoma, diffuse large B cell lymphoma and NK/T cell lymphoma. In summary, we present an approach to making an off-the-shelf T cell therapy that can rapidly translate to the clinic, requires no gene editing, and can serve as a platform for other CAR/TCRs to target a multiplicity of malignancies. Disclosures Quach: Tessa Therapeutics: Research Funding. Brenner:Memmgen: Membership on an entity's Board of Directors or advisory committees; Allogene: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Walking Fish: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Maker Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Other: Founder; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Founder; Tumstone: Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees. Heslop:Tessa Therapeutics: Consultancy, Research Funding; Novartis: Consultancy; Gilead Biosciences: Consultancy; PACT Pharma: Consultancy; Kiadis: Consultancy; AlloVir: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Marker Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Ramos:Novartis: Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Research Funding; Kuur Therapeutics: Research Funding. Rouce:Tessa Therapeutics: Other, Research Funding; Novartis: Honoraria. Rooney:Marker Therapeutics: Current equity holder in publicly-traded company, Other: co-founder; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Allovir: Current equity holder in publicly-traded company, Other: co-founder.

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The NLPHL Tumor Microenvironment Is Markedly Enriched in the Tigit and PD-1 Signalling Axes Compared to Classical Hodgkin Lymphoma

Blood ◽

10.1182/blood-2021-145840 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3513-3513

Author(s):

Jay Gunawardana ◽

Muhammed B. Sabdia ◽

Karolina Bednarska ◽

Soi C. Law ◽

Sandra Brosda ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Immune Checkpoint ◽

Research Funding ◽

Immune Checkpoint Blockade ◽

Checkpoint Blockade ◽

Immune Checkpoints ◽

Advisory Committees ◽

Tcr Repertoire

Abstract Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) comprises 5% of all Hodgkin lymphomas (HL). Its biology remains poorly characterized. Like classical HL (cHL), it contains minimal malignant cells embedded within a T cell rich intra-tumoral microenvironment (TME). Unlike cHL, it can transform to diffuse large B cell lymphoma (DLBCL). Immune-checkpoint blockade is effective in cHL but has minimal activity in DLBCL. No data is currently available regarding the potential to reactivate host anti-tumoral activity via immune-checkpoint blockade in NLPHL. Diagnostic FFPE samples from 49 NLPHL patients retrospectively collected from 4 Australian centres were interrogated. Inclusion criteria were sample availability and centrally confirmed histological NLPHL. Characteristics were in line with the literature: median age 45 years, range 13-82 years; F:M 1:3.5; stage I/II 55%, III/IV 35% (10% stage unknown) with the majority of cases were of immuno-architectural types A or C. RNA was digitally quantified using the NanoString 770-gene PanCancer Immune panel. Multi-spectral immunofluorescent (mIF) microscopy, plasma soluble PD-1 quantification, cell sorting, T cell receptor (TCR) repertoire analysis and functional immuno-assays were also performed. Results were compared with samples from 38 cHL and 35 DLBCL patients. We initially compared gene expression of NLPHL and cHL, looking for molecular similarities and differences. Ten non-lymphomatous nodes (NLN) were included as controls. Unsupervised clustering showed all but 3 NLPHL cases segregated from the cHL cluster. All NLN congregated in a discrete sub-cluster. As expected, RNA analysis showed significant enrichment for CD20 in NLPHL and CD30 in HL. Volcano plots (Fig. 1a), corrected for false-discovery showed marked variation in gene expression. For NLPHL (vs. cHL) there were 105 upregulated and 337 down regulated genes. Strikingly, the most significantly differentially over-expressed genes in NLPHL were all T cell related (CD247: CD3 zeta chain; CD3D: CD3 delta chain; GZMK: granzyme K; EOMES: marker of CD8 + T cell tolerance; and the immune checkpoints PDCD1: encodes for PD-1; and TIGIT). CD8B expression was increased in NLPHL. For cHL, the most over-expressed genes included macrophage-derived chemokines CCL17 and CCL22. Gene set enrichment analysis revealed activation of the PD-L1 expression and PD-1 checkpoint pathway and 9 of the top 10 Gene Ontology (GO) term enrichment scores involved lymphocyte signalling in NLPHL (Fig. 1b). To better appreciate the impact of the relevant immune checkpoints on their signalling axis, we compared gene ratios for PD-1 and TIGIT receptors with their ligands (PD-L1/L2 and PVR, respectively). NLPHL showed the highest enrichment ratios of these signalling pathways vs. cHL, DLBCL and NLN (Fig. 1c). Although it is known that CD4 +PD-1 +T cells form rosettes around NLPHL cells, the differential cellular localization of immune proteins has not been compared between HL entities. Using mIF, the proportion of intra-tumoral PD-1 + was markedly higher for CD4 + (~7-fold; p<0.0001) and CD8 + (~5-fold; p<0.001) T cells in NLPHL. However, the proportion of T cells expressing LAG3 was similar. Soluble PD-1 was elevated for both NLPHL and cHL, indicating circulating blood is influenced by the TME. For both HL entities over 80% of circulating CD4 + and CD8 + T cells expressed PD-1 alone or in combination with TIGIT. TCR repertoire analysis of sorted T cell subsets showed large intra-tumoral clonal T cell expansions were also detectable in circulating T cells. T cell clones were predominantly PD1 +CD4 + T cells in both HL types. Finally, we developed a functional assay using PD-L1/PD-L2 expressing NLPHL and cHL cell lines. These were co-cultured with genetically engineered PD-1 +CD4 + T cells that express a luciferase reporter. Similar levels of heightened T cell activation were seen with immune-checkpoint blockade for both HL entities, indicating that immune-checkpoint inhibition may also be of benefit in NLPHL. In conclusion, our multi-faceted analysis of the immunobiological features of the TME in NLPHL, provides a compelling rationale for early phase clinical studies that incorporate immune-checkpoint blockade in NLPHL. Figure 1 Figure 1. Disclosures Hawkes: Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Specialised Therapeutics: Consultancy; Merck KgA: Research Funding; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Antigene: Membership on an entity's Board of Directors or advisory committees; Regeneron: Speakers Bureau; Janssen: Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau. Swain: Janssen: Other: Travel expenses paid; Novartis: Other: Travel expenses paid. Keane: BMS: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Karyopharm: Consultancy; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Talaulikar: Takeda: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Jansenn: Honoraria, Research Funding; Roche: Honoraria, Research Funding; EUSA Pharma: Honoraria, Research Funding. Gandhi: janssen: Research Funding; novartis: Honoraria.

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Transcriptomic Features of Immune Exhaustion and Senescence Predict Outcomes and Define Checkpoint Blockade-Unresponsive Microenvironments in Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2021-145854 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 223-223

Author(s):

Sergio Rutella ◽

Jayakumar Vadakekolathu ◽

Francesco Mazziotta ◽

Stephen Reeder ◽

Tung On Yau ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Checkpoint Blockade ◽

Newly Diagnosed ◽

Advisory Committees ◽

Immune Exhaustion

Abstract Acute myeloid leukemia (AML) is a molecularly and clinically heterogeneous disease. Reinstating immunological control of AML is highly desirable to eradicate chemotherapy-resistant clones and provide long-term disease control. We recently identified bone marrow (BM) microenvironmental transcriptomic profiles that stratify patients with newly diagnosed AML into an immune-infiltrated and an immune-depleted subtype and that refine the accuracy of survival prediction beyond that afforded by current prognosticators (Vadakekolathu J et al., 2020). We have also shown that CD8 + T cells from patients with AML exhibit features of immune exhaustion and senescence (IES), including heightened expression of killer cell lectin-like receptor subfamily G member 1 (KLRG1) and B3GAT1 (encoding CD57) (Knaus H et al., 2018). Whether deranged T-cell functions affect the likelihood of responding to antitumor therapy, including immune checkpoint blockade (ICB), is an outstanding question in AML. In the current study, we analyzed 183 BM samples collected longitudinally at time of AML onset, response assessment and disease relapse from multiple cohorts of patients with AML treated with standard-of-care induction chemotherapy, and from 33 elderly AML patients with newly diagnosed or chemotherapy-refractory/relapsed AML treated with azacitidine, and the PD-1 checkpoint inhibitor pembrolizumab (NCT02845297). Primary patient specimens and associated clinical data were obtained via informed consent in accordance with the Declaration of Helsinki on research protocols approved by the Institutional Review Boards of the participating Institutions. RNA (150-200 ng) was extracted from BM aspirates and was processed on the nCounter FLEX analysis system (NanoString Technologies, Seattle, WA) using the PanCancer Immune profiling panel, as previously published (Vadakekolathu J et al., 2020). The correlation between transcriptomic features of IES, clinical characteristics, therapeutic response and patient outcome was validated using publicly available RNA-sequencing and NanoString data from 1,698 patients with AML, including samples from the TCGA-AML (n=147 cases), Beat-AML Master Trial (n=264 cases, of which 240 with survival data and 195 with chemotherapy response data) and Children's Oncology Group (COG)-TARGET AML series (n=145 cases). We initially showed that, compared with their non-senescent CD8 +CD57 -KLRG1 - counterpart, senescent CD8 +CD57 +KLRG1 + T cells are functionally impaired in terms of their ability to effect AML-blast killing mediated by an anti-CD33/CD3 bi-specific T-cell engager antibody construct (kindly provided by Amgen, USA; effector/target [E/T] ratio = 1:5). We then used gene set enrichment analysis (GSEA) to derive a transcriptomic signature of IES encompassing natural killer (NK)-cell and stem-like CD8 + T-cell markers, and showed that IES states correlate with lymphoid infiltration, adverse-risk molecular lesions (TP53 and RUNX1 mutations), experimental gene signatures of leukemia stemness (LSC17 score; Ng et al., 2016) and poor outcome in response to standard induction chemotherapy (Fig. 1A). In independent validation cohorts of children and adults with AML, the IES score was higher at baseline in patients with primary induction failure (following a standard 2 cycles of chemotherapy) compared with complete remission, increased in post-chemotherapy BM specimens, and predicted survival with greater accuracy than the ELN cytogenetic risk classifier (Fig. 1B). In the immunotherapy setting, high IES scores at baseline defined a checkpoint blockade-unresponsive AML tumor microenvironment and correlated with significantly shorter overall survival (9.1 versus 15.56 months in patients with high and low IES scores, respectively; HR = 3.32 (95% CI = 1.19-9.25); log-rank P = 0.021; Fig. 1C). Finally, the IES-related gene set also predicted for long-term outcomes and objective responses, based on RECIST criteria, to single-agent nivolumab or pembrolizumab, or combination anti-PD-1 + anti-CTLA-4, in 106 patients with melanoma (PRJEB23709 and GSE93157 series), a tumor type known to derive durable clinical benefit from ICB (Fig. 1D). Our findings encourage the pursuit of immune senescence reversal as a strategy to functionally reinvigorate T cells and could inform the delivery of ICB and other T cell-targeting immunotherapies to patients who are likely to benefit. Figure 1 Figure 1. Disclosures Radojcic: Syndax Pharmaceuticals: Research Funding; Regeneron Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Allakos: Membership on an entity's Board of Directors or advisory committees. Minden: Astellas: Consultancy. Tasian: Aleta Biotherapeutics: Consultancy; Gilead Sciences: Research Funding; Kura Oncology: Consultancy; Incyte Corporation: Research Funding.

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Treatment with DC/AML Fusion Vaccine and CD3xCD123 Bi-Specific T-Cell Engager (CD123-CODV-TCE) for Treatment of Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2021-148219 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 904-904

Author(s):

Dina Stroopinsky ◽

Anita G. Koshy ◽

Jessica J. Liegel ◽

Myrna Nahas ◽

Giulia Cheloni ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Ex Vivo ◽

Leukemia Cells ◽

Publicly Traded ◽

Advisory Committees ◽

Isotype Control ◽

Ifn Γ

Abstract Introduction: Immunotherapy for AML holds promise in overcoming chemotherapy resistance and in preserving immunologic memory necessary for durable remissions.A bispecific T-cell engaging antibody targeting CD3 and CD123 (CD123-CODV-TCE) has been shown to stimulate T cells to target CD123-expressing leukemic cells in vitroand in mouse models 1. While the short-term immune stimulation mediated by the CD123TCE has the potential to result in clinical response, long-term disease control will require the development of immune memory. We have developed a personalized cancer vaccine in which patient's dendritic cells are fused with autologous leukemia cells resulting in presentation of a wide range of antigens to the immune system. Here, we describe a novel combination of CD123TCE with a DC/AML fusion vaccine ex vivo and in a xenograft murine model. We hypothesized that the CD123TCE will direct the vaccine-educated T cells to not only more effectively eradicate target leukemia cells but also evoke a repertoire of memory T cells and long-term response. Methods/Results: AML cells expressing CD123 were isolated from bone marrow mononuclear cells (BMMCs) from AML patients (n=3). DCs were generated from autologous adherent peripheral blood mononuclear cells (PBMCs) obtained at the time of disease remission as previously described 2,3. Concurrently, CD3+ T cells were isolated from the non-adherent fraction of PBMCs using magnetic bead separation. Fusion cells were generated by co-culturing the DC and tumor cells at a ratio of 3:1 in the presence of polyethylene glycol (PEG). Vaccine educated T cells were then generated by co-culture of T cells with the autologous fusion cells at a ratio of 10:1 for 5-7 days followed by T cell expansion via CD3/CD28 ligation. The capacity of the vaccine-educated T cells to target autologous leukemia cells with the addition of CD123TCE was assessed. The results demonstrated a statistically significant increase in Granzyme B activity in the target AML cells following co-culture with vaccine-educated T cells and the addition of the CD123TCE, compared to T cells + isotype control (n=3). Furthermore, vaccine stimulation in combination with CD123TCE led to a robust increase in induction of tumor specific activated T cells as detected by CD137 expression and intracellular IFN-γ production after co-culture of vaccine-educated T cells with autologous tumor cells in the presence of CD123TCE. The addition of CD123TCE to vaccine-educated T cells resulted in mean 25.4% and 9.6% intracellular IFN-γ expression for CD8 and CD4 T cells, respectively, compared to 8.5 and 3.1% IFN-γ expression following the addition of isotype control (n=3). Next, we examined the efficacy of the combined treatment with vaccine-educated T cells and CD123TCE in-vivo, in two independent xenograft experiments. NSG mice were irradiated with 300rads and challenged with 1x10 6 patient-derived CD123+ tumor cells via retro-orbital injections. After detection of human AML engraftment in the PB on day 76, the mice were inoculated IV with 1X10 6 resting, or ex vivo fusion vaccine educated autologous T cells IV. Subsequently, cohorts of mice were treated with CD123TCE or an appropriate isotype control every 3 days IP. A significant decrease in human leukemia burden was detected in the peripheral blood, spleen and bone marrows of analyzed animals after treatment with vaccine educated T cells and isotype control, or resting T cells and CD123TCE, compared to untreated mice (n=5). Strikingly, no detectable AML was found in peripheral blood, spleens and bone marrows of mice treated with vaccine educated T cells in combination with TCE (n=5). Of note, treatment with vaccine educated T cells led to an expansion of human CD3+ T cells in tissues obtained from the analyzed animals. These human T cells persisted in mice treated with the CD123TCE with a two-fold increase in tumor-specific CD8+ T cells, as assessed by intracellular IFN-γ secretion following ex vivo stimulation with autologous tumor lysate. Conclusions: We demonstrated that the combination of DC/AML fusion vaccine and CD123TCE led to increase in tumor specific T cell immunity, both ex-vivo and in a xenograft murine model when compared to uneducated T cells with CD123TCE or educated T cells with isotype control molecule. Most significantly, the combination treatment was shown to eradicate AML in this model with all animals remaining disease-free several months post inoculation. Disclosures Stroopinsky: The Blackstone Group: Consultancy. Nahas: Kite Pharma: Current Employment. Fraenkel: Sanofi: Current Employment. Yildirim: Sanofi: Current Employment. Bonnevaux: Sanofi: Current Employment. Guerif: Sanofi: Current Employment. Kufe: Genus Oncology: Current equity holder in publicly-traded company; Canbas: Consultancy; REATA: Consultancy, Current equity holder in publicly-traded company; Hillstream BioPharma: Current equity holder in publicly-traded company. Rosenblatt: Parexel: Consultancy; Wolters Kluwer Health: Consultancy, Patents & Royalties; Bristol-Myers Squibb: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Imaging Endpoints: Consultancy; Attivare Therapeutics: Consultancy. Avigan: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Kite Pharma: Consultancy, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Partner Tx: Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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; Aviv MedTech Ltd: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Legend Biotech: Membership on an entity's Board of Directors or advisory committees; Chugai: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Parexcel: Consultancy; Takeda: Consultancy; Sanofi: Consultancy.

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Decade-Long Remissions of Leukemia Sustained By the Persistence of Activated CD4+ CAR T-Cells

Blood ◽

10.1182/blood-2021-152664 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 166-166

Author(s):

J. Joseph Melenhorst ◽

Gregory M Chen ◽

Meng Wang ◽

David L. Porter ◽

Peng Gao ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Advisory Committees ◽

Car T Cells ◽

Car T Cell ◽

Car T ◽

Post Infusion

Abstract The adoptive transfer of chimeric antigen receptor (CAR)-reprogrammed T lymphocytes has demonstrated significant potential in various malignancies. Functional persistence of CAR T-cells in chronic lymphocytic leukemia (CLL) is a key predictor of durable remissions, yet the characteristics of long-term persisting CAR-engineered T cells have not been extensively studied. We here studied the fate of CD19-specific (CAR19) T-cells in two leukemia patients who achieved and sustained a complete remission over a decade ago. Molecular fate mapping was carried out on long-term persisting CAR T cells using lentiviral vector integration site sequencing across multiple time points up to 9.0 and 7.2 years post-infusion in patients 1 and 2, respectively. This analysis revealed little if any CAR T-cell clonal stability in the first 1.6 years in patient 1. Close to year 2 the CAR T cell repertoire stabilized in the first patient, with a strong clonal focusing until the last follow-up. The second patient had episodes of repertoire stability from the first month to approximately 12 months later, as well as from year 1 to 5. The CAR T cell repertoire in both patients were dominated by a few clones which were detected across a multiyear time span. CAR T-cells were still detectable using flow and mass cytometry 10+ years post-infusion. Deep immunophenotyping using a 40-marker mass cytometry panel identified divergence in effector but convergence in memory CAR T cell characteristics, with a prominent highly activated effector-memory CD4+ population developing late after infusion, expressing immune regulatory molecules. The CD4+ CAR T-cells were notable for a subpopulation highly expressing Ki67, suggestive of a proliferative phenotype. Ki67[hi] CD4+ CAR T-cells steadily emerged as the dominant population in both patients: this population constituted 15.9% of CAR T-cells at month 1.8 in patient 1, increasing to 97.0% by year 9.3; and constituted 0.2% of CAR T-cells in patient 2 at month 2.4, increasing to 87.2% by year 7.2. We assessed Ki67 expression in the CD4+ CAR T-cells compared to the CAR-negative T cells from these patients at matched time points, finding that this level of Ki67 expression was strongly CAR T-cell specific. CD8+ CAR T-cells also exhibited a proliferative trend overall, but Ki67 expression was generally lower and less robustly observed compared to the CD4+ CAR T-cell subset. These Ki67[hi] CD4+ T cells expressed a distinct marker profile, including activation markers CD38, HLA-DR, and CD95; transcription factors EOMES and TOX; checkpoint markers CTLA-4, LAG-3, TIGIT; and memory markers CD27 and CCR7. Together, these data suggest two major phases of CAR T-cell therapy responses in these patients: an initial response phase dominated by cytotoxic CD8+ T cells and double-negative Helios[hi] CAR T-cells, and a long-term remission phase dominated by a uniquely proliferative CD4+ CAR T-cell phenotype. To characterize these long-persisting CAR T-cells at a single-cell resolution, we performed CITE-Seq with single-cell T cell receptor-beta VDJ profiling on CAR T-cells obtained 9.3 years post-infusion. These long-persisting CAR T-cells exhibited strong evidence of ongoing activation, proliferation, and aerobic glycolysis despite evidence of chronic antigen-mediated signaling. Our data in aggregate provide important insight into and the development of a long-term memory anti-tumor response, necessary for sustained remission in leukemia following CAR T-cell therapy. Disclosures Porter: Wiley and Sons Publishing: Honoraria; Novartis: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Unity: Patents & Royalties; National Marrow Donor Program: Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Membership on an entity's Board of Directors or advisory committees; GenenTech: Current Employment, Current equity holder in publicly-traded company; Incyte: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; DeCart: Membership on an entity's Board of Directors or advisory committees; ASH: Membership on an entity's Board of Directors or advisory committees; American Society for Transplantation and Cellular Therapy: Honoraria. Pruteanu-Malinici: Novartis: Current Employment. Frey: Sana Biotechnology: Consultancy; Novartis: Research Funding; Syndax Pharmaceuticals: Consultancy; Kite Pharma: Consultancy. Gill: Interius Biotherapeutics: Current holder of stock options in a privately-held company, Research Funding; Novartis: Other: licensed intellectual property, Research Funding; Carisma Therapeutics: Current holder of stock options in a privately-held company, Research Funding. Davis: Tmunity Therapeutics: Consultancy, Patents & Royalties, Research Funding; Cellares Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Patents & Royalties. Brogdon: Novartis Institutes for Biomedical Research: Current Employment. Young: Novartis: Patents & Royalties; Tmunity Therapeutics: Patents & Royalties. Levine: Immuneel: Membership on an entity's Board of Directors or advisory committees; In8bio: Membership on an entity's Board of Directors or advisory committees; Immusoft: Membership on an entity's Board of Directors or advisory committees; Akron: Membership on an entity's Board of Directors or advisory committees; Ori Biotech: Membership on an entity's Board of Directors or advisory committees; Vycellix: Membership on an entity's Board of Directors or advisory committees; Avectas: Membership on an entity's Board of Directors or advisory committees; Tmunity Therapeutics: Other: Co-Founder and equity holder. Siegel: Vetigenics, LLC: Other: Co-Founder and Equity Holder; Verismo Therapeutics, Inc: Other: Co-Founder and Equity Holder. Wherry: Merck: Consultancy; Marengo: Consultancy; Janssen: Consultancy; Related Sciences: Consultancy; Synthekine: Consultancy; Surface Oncology: Consultancy. June: AC Immune, DeCART, BluesphereBio, Carisma, Cellares, Celldex, Cabaletta, Poseida, Verismo, Ziopharm: Consultancy; Tmunity, DeCART, BluesphereBio, Carisma, Cellares, Celldex, Cabaletta, Poseida, Verismo, Ziopharm: Current equity holder in publicly-traded company; Novartis: Patents & Royalties.

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Donor-Derived Adoptive T-Cell Therapy Targeting Multiple Tumor Associated Antigens to Prevent Post-Transplant Relapse in Patients with ALL

Blood ◽

10.1182/blood-2021-149332 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 471-471

Author(s):

Swati Naik ◽

Spyridoula Vasileiou ◽

Ifigeneia Tzannou ◽

Manik Kuvalekar ◽

Ayumi Watanabe ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Management Support ◽

Publicly Traded ◽

Advisory Committees ◽

Post Infusion ◽

T Cell Lines

Abstract Background: Hematopoietic stem cell transplant (HSCT) is a curative option for patients with high-risk Acute Lymphoblastic Leukemia (HR-ALL), but relapse remains a major cause of treatment failure. Strategies to enhance the graft-versus-leukemia (GVL) effect have been employed to prevent relapse, including modulating immune suppression post-HSCT to hasten immune reconstitution or with the use of donor lymphocyte infusions (DLIs). However, DLIs carry a significant risk of graft-versus-host disease (GVHD) due to the concurrent transfer of alloreactive T cells. To enhance the GVL effect while minimizing GVHD, we developed a protocol for the generation of ex vivo expanded, donor-derived T-cell lines targeting PRAME, WT1 and Survivin - tumor associated antigens that are frequently expressed in both B- and T-cell ALL. These multi-antigen-targeted T cells (multiTAAs) were adoptively transferred to pediatric and adult patients with HR-ALL who had undergone an allogeneic HSCT. Methods: Donor-derived multiTAA-specific T cells were generated by co-culturing PBMCs with autologous DCs loaded with pepmixes (15 mer peptides overlapping by 11 amino acids) spanning all 3 target antigens in the presence of a Th1-polarizing/pro-proliferative cytokine cocktail. Following 2-4 rounds of stimulation these multiTAA-specific T cells were infused to patients with ALL who had undergone an HSCT but remained at a high risk for disease relapse. Results: We have generated 15 clinical grade multiTAA-specific T cell lines comprising CD3+ T cells (mean 95.1±1.9%) with a mixture of CD4+ (mean 22.8±6.3%) and CD8+ (mean 52.5±5.3%) cells, which expressed central [CD45RO+/CD62L+: 13.5±2.8%] and effector memory markers [CD45RO+/CD62L-: 56.4±3.8%]. The expanded lines recognized the targeted antigens PRAME (range 0-370 SFC/2x10 5), WT1 (0-363 SFC/2x10 5), and Survivin (0-65 SFC/2x10 5) in an IFNg ELIspot. None of the lines reacted against non-malignant patient-derived cells (3.7±0.8% specific lysis; E: T 20:1) - a study release criterion indicating lack of alloreactivity. We have infused 11 HR-ALL patients (8 pediatric and 3 adult) with donor-derived multiTAA-specific T cells to prevent disease relapse (Table 1). Patients were administered with up to 4 infusions of cells at 3 escalating dose levels, ranging from 0.5 - 2x10 7 cells/m 2. Infusions were well tolerated with no dose-limiting toxicity, GVHD, cytokine release syndrome or other adverse events. Three patients were not evaluable per study criteria as they received >0.5mg/kg of steroids (2 patients received stress doses for septic shock and 1 for elevated liver enzymes presumed to be GVHD that was later ruled out) within 4 weeks of infusion and were replaced. Six of the 8 remaining patients infused remain in CR on long-term follow up at a median of 46.5 months post-infusion (range 9-51 months). In patients who remained in long term CR we detected an expansion of tumor-reactive T cells in their peripheral blood post-infusion against both targeted (WT1, Survivin, PRAME) and non-targeted antigens (SSX2, MAGE-A4, -A1, -A2B, -C1, MART1, AFP and NYESO1) reflecting epitope and antigen spreading, which correlated temporally (within 4 weeks) with multiTAA infusions. By contrast in the two patients who relapsed we saw no evidence of in vivo T cell amplification within the first 4 weeks after infusion. Conclusion: The preparation and infusion of donor-derived multiTAA-specific T cells to patients with B- and T-ALL post allogeneic HSCT is feasible, safe and as evidenced by in vivo tumor-directed T cell expansion and antigen spreading in patients, may contribute to disease control. This strategy may present a promising addition to current immunotherapeutic approaches for prophylaxis for leukemic relapse in HSCT recipients. Figure 1 Figure 1. Disclosures Vasileiou: Allovir: Consultancy. Tzannou: Gileas: Honoraria; Allovir: Current equity holder in publicly-traded company. Kuvalekar: Allovir: Consultancy. Watanabe: Allovir: Consultancy. Grilley: QB Regulatory Consulting: Other: Ownership, project management support, Research Funding; Marker: Consultancy, Other: Regulatory and project management support; Allovir: Current equity holder in publicly-traded company, Other: Leadership. Hill: Incyte: Membership on an entity's Board of Directors or advisory committees. Omer: Allovir: Research Funding. Gottschalk: Tessa Therapeutics: Consultancy; Immatics: Membership on an entity's Board of Directors or advisory committees; Other: Other: patents and patent applications in the field of cancer cell and gene therapy ; Tidal: Consultancy; Novartis: Consultancy; Catamaran Bio: Consultancy. Heslop: Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Kiadis: Membership on an entity's Board of Directors or advisory committees; Kuur Therapeutics: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees; Allovir: Current equity holder in publicly-traded company; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Marker Therapeutics: Current equity holder in publicly-traded company; Fresh Wind Biotherapies: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Rooney: Allogene: Patents & Royalties; Bellicum: Patents & Royalties; Bluebird: Current equity holder in publicly-traded company; Allovir: Current equity holder in publicly-traded company; Alimera: Consultancy; Memgen: Consultancy; TScan Therapeutics: Consultancy; Takeda: Patents & Royalties; Marker: Current equity holder in publicly-traded company; Tessa: Consultancy, Other: Leadership, Research Funding. Vera: Allovir: Consultancy, Current equity holder in publicly-traded company, Other: Leadership, travel , accomodations, expenses, Patents & Royalties; Marker: Current Employment, Other: Travel, Accomodations, Expenses, Patents & Royalties, Research Funding. Leen: Allovir: Consultancy, Current equity holder in publicly-traded company; Marker: Current equity holder in publicly-traded company.

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Ibrutinib Treatment Reduces Myeloid Derived Suppressor Cell Numbers and Function in Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood-2018-99-114799 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 239-239

Author(s):

Gerardo Ferrer ◽

Byeongho Jung ◽

Aslam Rukhsana ◽

Pui Yan Chiu ◽

Andrea Nicola Mazzarello ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

T Cell Differentiation ◽

Th1 Cells ◽

Advisory Committees ◽

Cell Counts

Abstract In chronic lymphocytic leukemia (CLL), bidirectional interactions of leukemic B cells with components of a complex, yet incompletely defined tumor microenvironment (TME) are critical for leukemic cell survival and proliferation. Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, blocks signals that are crucial for survival of CLL cells which are delivered by the B cell receptor (BCR) and certain other receptors. However since BTK and its family members are expressed by other cell types, ibrutinib can also affect non-leukemic cells, thereby altering their function. Here, we focused on understanding how myeloid-derived suppressor cells (MDSCs), a non-leukemic cell type within the TME, and their main target, T cells, are affected by ibrutinib therapy. Using blood cells from a set of 20 previously untreated patients receiving ibrutinib, we analyzed circulating MDSCs and their subsets 15 days before and 1, 2 and 3 months after treatment initiation. As anticipated, at the first month time point the absolute CLL B-cell count increased significantly (P=0.024), followed by a progressive reduction at consecutive time points (P<0.001). In contrast, absolute MDSC numbers slowly and continuously decreased over time, achieving a significant reduction by the third month (P=0.009). When dividing MDSCs into their cellular subsets, the same pattern was observed for granulocyte-like MDSCs (gMDSCs) (P=0.005) but not for monocyte-like MDSCs (mMDSCs); for the latter an insignificant change was found. Of note, when comparing the changes of MDSC and gMDSC numbers to that of CLL B-cell counts, MDSC and gMDSC neared statistical significance at month one (P<0.1) and achieved significance at the second month (MDSCs: P<0.001; gMDSCs: P=0.033). We also observed differences in T-cell subpopulations shortly after ibrutinib treatment began. T cell counts increased significantly at the second month compared to pre-treatment (P=0.024); this was the case for both CD4+ and CD8+ cells (P = 0.022 and 0.010, respectively). In addition, CD8+ T cells maintained significance through the third month (P = 0.033). When exploring T cell subsets defined by cytokine production, we observed a spike at the second month of CD4+IL17F+ and of CD8+IL17F+, CD8+IL17A+ and CD8+FoxP3+ T cells. However, by the 3rd month, only the IFNγ-producing subset of CD4+ and CD8+ T cells were significantly higher (P = 0.049 and 0.042, respectively). Next we analyzed the function of gMDSCs and mMDSCs in the presence of ibrutinib in vitro, addressing the two main effects of these cells on T lymphocytes: suppression of T-cell proliferation and modulation of T-cell differentiation. Specifically, ibrutinib did not directly reduce T-cell expansion in the absence of MDSCs and did not alter the effect of CLL gMDSCs nor mMDSCs on T-cell proliferation, since the significant reduction induced by gMDSCs (P=0.047) and the insignificant, variable effect of mMDSCs were unchanged by the drug. However when we analyzed the influence of gMDSCs, mMDSCs and monocytes on naïve CD4+ T-cell differentiation in the presence or absence of ibrutinib, to our surprise the only T cell subpopulation directly compromised by ibrutinib was the Th1/IFNγ-producing subset. This was opposite that observed in co-cultures with gMDSCs, mMDSCs or normal monocytes in the presence of ibrutinib where Th1 cells expanded significantly (P= 0.021, 0.010, and 0.005, respectively). In the latter co-cultures not containing ibrutinib, more IL-4-producing (Th2) cells were found. Additionally, ibrutinib had a positive effect on IL-22+ (Th22) and FoxP3+ (Treg) cell numbers in the presence of MDSCs and monocytes. In summary, opposite to what we observed for CLL B and T cells, MDSC counts fell progressively after initiating ibrutinib therapy, possibly due to a direct effect of ibrutinib on BTK in MDSCs or an indirect effect mediated by diminishing signals from CLL B cells that would normally be delivered after BCR engagement. Ibrutinib did not directly alter the T cell suppressive ability of MDSCs, but it did skew T-cell differentiation to Th1 cells when MDSCs were present, in line with our finding higher Th1 cells in the blood after 3 months of treatment. Thus over time, ibrutinib shifts the CLL TME from an immunosuppressive to a more immune effective one. Disclosures Chen: Beigene: Research Funding; Verastem: Research Funding; Pharmacyclics: Research Funding. Barrientos:Pharmacyclics, an AbbVie Company: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Janssen: Consultancy. Kolitz:Magellan Health: Consultancy, Honoraria. Rai:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Cellectis: Membership on an entity's Board of Directors or advisory committees; Roche/Genentech: Membership on an entity's Board of Directors or advisory committees. Chiorazzi:Janssen, Inc: Consultancy; AR Pharma: Equity Ownership.

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