scholarly journals 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 ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 16-16
Author(s):  
David H. Quach ◽  
Haran R. Ganesh ◽  
Sachin Thakkar ◽  
Luis Becerra-Dominguez ◽  
Birju Mehta ◽  
...  

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.

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3488-3488
Author(s):  
Jinsheng Weng ◽  
Kelsey Moriarty ◽  
Yong Pan ◽  
Man Chun John MA ◽  
Rohit Mathur ◽  
...  

Abstract Chimeric antigen receptor (CAR)-modified T-cell therapy targeting CD19 induces high response rates in patients with relapsed or refractory B-cell lymphomas. However, about 60% of patients experience primary or secondary resistance after CD19-targeted CAR T-cell therapy and a major of cause of failure appears to be due to loss of CD19 expression on the tumor. Therefore, novel targets for adoptive T-cell therapeutic approaches are needed to further improve clinical outcome in these patients. T-cell leukemia/lymphoma antigen1 (TCL1) is an oncoprotein that is overexpressed in multiple B-cell malignancies including follicular lymphoma (FL), mantle cell lymphoma (MCL), diffuse large B-cell lymphoma (DLBCL), and chronic lymphocytic leukemia (CLL). Importantly, it has restricted expression in only a subset of B cells among normal tissues. We previously identified a TCL1-derived HLA-A2-binding epitope (TCL170-79 SLLPIMWQLY) that can be used to generate TCL1-specific CD8+ T cells from peripheral blood mononuclear cells of both HLA-A2+ normal donors and lymphoma patients. More importantly, we showed that the TCL1-specific CD8+ T cells lysed autologous primary lymphoma cells but not normal B cells (Weng et al. Blood 2012). To translate the above discovery into clinic, we cloned the T-cell receptor (TCR) alpha and beta chains from a TCL1-specific CD8+ T-cell clone and showed that this TCL1-TCR could be transduced into polyclonal donor T cells using a lentiviral system with a transduction efficiency of >40% as determined by TCL170-79 tetramer positive T cells. Furthermore, we demonstrated that the TCL1-TCR-transduced T cells recognized T2 cells pulsed with TCL170-79 peptide producing IFN- γ >8 ng/ml and IL-2 >350 ng/ml but were not reactive to control HIV-Gag peptide (IFN- γ <0.1 ng/ml and IL-2 <0.2 ng/ml). The TCL1-TCR-transduced T cells recognized TCL170-79 peptide pulsed onto T2 cells at a concentration of 1-10 nM (IL-2 >10 ng/ml) suggesting it has moderate to high avidity. Importantly, TCL1-TCR-transduced T cells lysed HLA-A2+ (up to 43% lysis of Mino and 25% lysis of Jeko-1 at 40:1 Effector:Target ratio) but not HLA-A2- lymphoma cell lines (5.5% lysis of HLA A2- Raji and 2.3% lysis of Daudi at 40:1 Effector:Target ratio). TCL1-TCR-transduced T cells were also cytotoxic to HLA-A2+ primary lymphoma tumor cells (up to 48% lysis of CLL, 43% lysis of FL, 41% lysis of DLBCL, 46% lysis of splenic marginal zone lymphoma, and 11% lysis of MCL at 40:1 Effector:Target ratio) but not normal B cells derived from the same patients. Lastly, TCL1-TCR transduced T cells showed high efficacy in in vivo models. Adoptive transfer of the TCL1-TCR-tranduced T cells significantly reduced lymphoma tumor growth and extended survival in Mino mantle cell lymphoma cell line xenograft model (48% survival in TCL1-TCR-T treated group vs. 12.5% survival in control group at 10 weeks n=7-8 mice/group; P=0.02). Collectively, our data suggest that the high expression in B-cell tumors, restricted expression in normal tissues, and presence of an immunogenic CD8 T-cell epitope, make TCL1 a target for T cell-based therapeutic approaches in multiple B-cell malignancies. Our results also demonstrate that the TCL1-specific TCR-transduced T cells may serve as a novel adoptive immunotherapy approach for the treatment of patients with various B-cell malignancies (including FL, MCL, DLBCL, CLL). Acknowledgments: This study is supported by MD Anderson Moon Shot Program and CPRIT and the National Natural Science Foundation of China Grant (No. 81570189) Disclosures Neelapu: Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellectis: Research Funding; Poseida: Research Funding; Merck: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Research Funding; Karus: Research Funding; Bristol-Myers Squibb: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Unum Therapeutics: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 16-17 ◽  
Author(s):  
Martin Hutchings ◽  
Fritz C. Offner ◽  
Francesc Bosch ◽  
Giuseppe Gritti ◽  
Carmelo Carlo-Stella ◽  
...  

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.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 75-75
Author(s):  
Jooeun Bae ◽  
Shuichi Kitayama ◽  
Laurence Daheron ◽  
Zach Herbert ◽  
Nikhil C. Munshi ◽  
...  

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 &lt; 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.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 748-748
Author(s):  
Ashley V Geerlinks ◽  
Brooks Scull ◽  
Christa Krupski ◽  
Ryan Fleischmann ◽  
Michael A. Pulsipher ◽  
...  

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 &lt;5% prior to day +42. Secondary GF was defined as donor chimerism &lt;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 &lt;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 &gt;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 &gt;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 &gt;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 &gt;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 &gt;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


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2537-2537
Author(s):  
Lauren C Shapiro ◽  
Radhika Gali ◽  
Astha Thakkar ◽  
Jesus D Gonzalez-Lugo ◽  
Abdul Hamid Bazarbachi ◽  
...  

Abstract It is well established that COVID-19 carries a higher risk of morbidity and mortality in patients (pts) with hematologic malignancies. Emerging data suggests that despite the 3 COVID-19 vaccines with emergency use authorization (EUA) by the FDA inducing high levels of immunity in the general population, pts with hematologic malignancies have lower rates of seroconversion for the SARS-CoV-2 Spike antibody (Spike IgG) and thus possibly lower protection against severe COVID-19. We established a program of rapid vaccination and evaluation of response in an inner city minority population to help determine the factors that contribute to the poor seroconversion to COVID-19 vaccination in pts with hematologic malignancies. We conducted a cross-sectional cohort study of pts with hematologic malignancies seen at Montefiore Medical Center between March 29, 2021 and July 8, 2021 who completed their vaccination series with 1 of the 3 FDA EUA COVID-19 vaccines, Moderna, Pfizer, or Johnson & Johnson (J&J). We qualitatively measured Spike IgG production in all pts using the AdviseDx Spike IgG assay and performed quantitative analysis on pts who completed their vaccination series with at least 14 days (d) after the 2 nd dose of the Moderna or Pfizer vaccines or 28d after the single J&J vaccine. Safety data was collected via questionnaires or as part of the electronic medical record. We analyzed the characteristics of these pts using standard descriptive statistics and associations between pts characteristics, cancer subtypes, treatments, and vaccine response using a Fisher Exact test, Kruskal-Wallis Rank Sum test, or Kendall Tau-b test. A total of 121 pts with hematologic malignancies were enrolled and another 10 pts were included by retrospective chart review. Five pts did not have a Spike IgG performed after consent and excluded. Ten patients had Spike IgG testing before completion of their vaccination series and excluded from quantitative analyses. A total of 116 pts were included in immunogenicity analysis and 106 pts in quantitative analysis. Baseline characteristics and representative malignancies are listed in Table 1. Seventy pts (60%) received Pfizer, 36 pts (31%) Moderna, and 10 pts (9%) J&J. Median time from vaccination completion to Spike IgG was 40d. We observed a high-rate of seropositivity (86%) with 16 pts (14%) having a negative Spike IgG. Percent positivity was not statistically significant between vaccine types (p=0.50). We observed significantly lower seroconversion rates in pts with Non-Hodgkin lymphoma (p=0.005) and pts who received: cytotoxic chemotherapy (p=0.002), IVIG (p=0.01), CAR-T cell therapy (p=0.00002), and CD20 monoclonal antibodies (Ab) (p=0.0000008) especially within 6 mo of Spike Ab evaluation (p=0.01). All pts who received anti-CD19 (Axi-cel) CAR-T therapy (0/6) were seronegative, and 1 pt that received BCMA directed CAR-T (Cilta-cel) was seropositive with no association between timing CAR-T cell infusion and seroconversion/titer. Use of BCL2 inhibitors (p=0.04), CD20 monoclonal Ab (p=0.0009), CAR-T cell therapy (p=0.01), BTK inhibitors (p=0.04), current steroid use (p=0.002), and IVIG (p=0.003) also correlated with significantly lower Ab titers with a trend toward lower Ab titers in pts on any active cancer therapy at time of vaccination (p=0.051). Immunomodulatory drugs (p=0.01) and proteasome inhibitors (p=0.01) had significantly higher seroconversion rates, and pts with history prior COVID-19 (12/106) had significantly higher Ab titers (p=0.0003). Of 47 pts who received stem cell transplant, 43 received an autologous (37 seropositive, 6 seronegative) and 4 an allogeneic transplant (3 seropositive, 1 seronegative), with no significant association with seroconversion, Ab titer, or time since transplant (greater or less than 1 year). The majority of pts, 64% and 53%, reported no adverse effects (AE) to the 1 st and 2 nd dose respectively. The most common AE were mild in severity and included sore arm, muscle aches, fatigue, and fever. No life-threatening AE were observed. Our findings indicate that vaccination is safe, effective, and well tolerated in the majority of pts with hematologic malignancies. We observed that pts receiving B-cell depleting therapies are unable to mount an effective serological response to COVID-19 vaccines and remain vulnerable to the disease. Novel immunization strategies (active or passive) are urgently needed in this population. Figure 1 Figure 1. Disclosures Gritsman: iOnctura: Research Funding. Shastri: Onclive: Honoraria; Kymera Therapeutics: Research Funding; Guidepoint: Consultancy; GLC: Consultancy. Halmos: Merck: 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; Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Research Funding; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Mirati: Research Funding; Elevation: Research Funding; Blueprint: Research Funding; Advaxis: Research Funding; Eli-Lilly: Research Funding; TPT: Membership on an entity's Board of Directors or advisory committees; Apollomics: Membership on an entity's Board of Directors or advisory committees; Guardant Health: Membership on an entity's Board of Directors or advisory committees. Verma: BMS: Research Funding; GSK: Research Funding; Novartis: Consultancy; Stelexis: Consultancy, Current equity holder in publicly-traded company; Eli Lilly: Research Funding; Curis: Research Funding; Medpacto: Research Funding; Incyte: Research Funding; Acceleron: Consultancy; Stelexis: Current equity holder in publicly-traded company; Celgene: Consultancy; Throws Exception: Current equity holder in publicly-traded company.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 14-14
Author(s):  
Mehmet K. Samur ◽  
Mariateresa Fulciniti ◽  
Anil Aktas-Samur ◽  
Abdul Hamid Bazarbachi ◽  
Yu-Tzu Tai ◽  
...  

Chimeric antigen receptor (CAR) T-cell therapy targeting B cell maturation antigen (BCMA) has provided deep (73% - 100%) responses in relapsed/refractory multiple myeloma (MM). However, median PFS has been less than 12 months, and amongst the small number of patients retreated at the time of progression with the same CAR T product, responses have been infrequent. This highlights development of resistance that may preclude effectiveness of the 2ndinfusion, and may also underly relapse following response to the initial CAR-T cell therapy. Here, we have investigated one of the resistance mechanisms using longitudinal single cell transcriptomic and bulk genomic analysis. This patient had relapsed/refractory IgG lambda MM with hypodiploidy and a complex karyotype with t(8;12) (q24;q14), clonal t(11;14) (q13;q32), and clonal deletion 13. Patient received 150x106CAR+ T cells (ide-cel) and achieved partial response, with duration of response of 8 months. The patient was retreated with 450 x106CAR+ T cells at relapse, but with no response. To delineate the resistance mechanism, we evaluated the bone marrow (BM) niche using 37658 cells from eight time points from before 1st CAR T cell infusion to 2 months after 2nd CAR T cell infusion, and identified 13 clusters consisting of hematopoietic cells and MM/plasma cells. Using RT-PCR based detection, we observed engineered CAR T cells only at 2 weeks after first infusion, when maximal CAR T cell expansion was observed. We did not observe infused CAR T cells with single cell RNAseq after 2ndinfusion, but a limited expansion was confirmed using RT-PCR.Re-clustering of the T cell cluster showed an increased proportion of CD4+ helper and T regulatory cells (Treg) 2 weeks after 1st infusion. In contrast, TREG proportion remained constant at the 2nd infusion, suggesting other causes for lack of expansion of CAR-T cells. We also did not identify any significant increase in the proportion of cells expressing immune check point inhibitory markers or in accessory cell types with immune inhibitory function in MM BM. Since we did not delinate a role of the BM milieu mediating suppression of CAR-T cell expansion and function following 2ndinfusion, we next explored tumor intrinsic factors. Soluble BCMA level (produced predominantly by MM cells) was high before the first CAR T cell infusion and dropped significantly to a very low level coinciding with the clinical response; however, it remained low even at the time of relapse with increase burden of MM, indicating a lack of BCMA production by MM cells. We therefore investigated genomic changes in MM cells at the time of relapse. Our single cell analysis of BM samples identified 3 samples (at the time of relapse and post 2ndCAR T cell infusion) with significant numbers of MM cells, evidenced by expression of CD138 and XBP1 (marker of plasma cells), CCND1 (upregulated in this patient with t(11;14)) and lack of RB1 (downregulated in this patient with del13). Imputation of copy number alterations scRNAseq showed that the majority of MM cells had a deletion of 16p, including the BCMA locus located on 16p13.13. We further validated these findings using deep whole exome sequencing (WES) of purified CD138+ cells collected after the second CAR T infusion. Before first CAR T cell infusion, 4% MM cells showed deletion 17p, while after second infusion both WES and scRNAseq prediction showed that del17p and del16p were clonal, and longitudinal scRNAseq analysis indicated that del17p and del16p co-occurred in the same clone. Moreover, WES identified a subclonal nonsense mutation (p.Q38*) in BCMA that creates an early stop codon in the BCMA gene. This biallelic BCMA deletion, acquired with one copy loss and a 2ndloss-of-function mutation, provides the molecular basis for lack of BCMA expression in MM cells at the time of relapse. Our data showed that both TP53 and BCMA had deletion in one allele and mutation in the second allele. These results identify biallelic loss of BCMA locus as a potential resistance mechanism to BCMA targeting therapy. Our results highlight the need to investigate sBCMA as a potential indicator of BCMA loss at relapse, and to carry out detailed transcriptomic or genomic analysis to confirm mutations. Moreover, these data also demonstrate the ability of MM cells to survive without BCMA expression. With the growing number of BCMA targeting therapeutic modalities under development, we would expect to see such occurrences more commonly in the future. Disclosures Fulciniti: NIH: Research Funding. Campbell:BMS: Current Employment, Current equity holder in publicly-traded company. Petrocca:bluebird, bio: Current Employment, Current equity holder in publicly-traded company. Hege:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Patents & Royalties: numerous, Research Funding; Celgene (acquired by Bristol Myers Squibb): Ended employment in the past 24 months; Mersana Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Arcus Biosciences (Former Board of Directors): Divested equity in a private or publicly-traded company in the past 24 months. Kaiser:BMS: Current Employment, Current equity holder in publicly-traded company. Anderson:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Celgene: 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; Oncopep and C4 Therapeutics.: Other: Scientific Founder of Oncopep and C4 Therapeutics.. Munshi:C4: Current equity holder in private company; Legend: Consultancy; OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; BMS: Consultancy; Janssen: Consultancy; Adaptive: Consultancy; Amgen: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1763-1763
Author(s):  
David H. Quach ◽  
Carlos A. Ramos ◽  
Premal D. Lulla ◽  
Sandhya Sharma ◽  
Haran R. Ganesh ◽  
...  

Abstract The manufacture of individual patient-derived CAR T-cells is expensive, frequently unsuccessful, too time consuming to benefit acutely ill patients and difficult to scale for large numbers of patients. "Off-the-shelf" T cell products that are banked from healthy donors would improve accessibility, allow rapid treatment, and reduce costs. The major obstacles to the success of allogeneic T cells are graft-versus-host disease (GVHD) and graft rejection, mediated by host and recipient alloreactive T cells, respectively. To address GVHD, we are using allogeneic Epstein-Barr Virus-specific T cells (EBVSTs), which have not produced GVHD in more than 300 recipients. To prevent graft rejection we have expressed a chimeric antigen receptor for CD30 (CD30.CAR) in EBVSTs. CD30 will be upregulated by host alloreactive T cells when they encounter infused CD30.CAR EBVSTs. As a consequence, they will become targets for the CD30.CAR EBVSTs. Previous clinical studies (NCT02917083, NCT01555892, and NCT00062868) have shown that CD30.CAR T cells can destroy CD30+ lymphoma cells through their chimeric receptor, while EBVSTs can kill EBV+ lymphoma cells through their native TCR. Thus, once engrafted, banked CD30.CAR EBVSTs may kill both CD30+ and EBV+ lymphomas through their CAR and TCR respectively without causing GVHD. To assess the safety and activity of banked CD30.CAR EBVSTs, we treated patients with multiply relapsed (median of 4 prior lines of therapy; range 3-5) or refractory CD30-positive lymphomas in a Phase 1 dose escalation study using 4 × 10 7, 1 × 10 8 or 4 × 10 8 CD30.CAR EBVSTs infused after lymphodepletion with cyclophosphamide and fludarabine. Although CD30.CAR killing is not HLA restricted, selection of the CD30.CAR EBVST product for each recipient was based on the best HLA class I and class II match; this should allow endogenous EBV (when present) to boost the in vivo activity of CD30.CAR EBVSTs via their native TCRs, and augment reactivity in patients whose CD30+ malignancies are also EBV+. We have currently treated eight patients, including two at the highest dose level. The infusions have been well tolerated with no dose-limiting toxicities and in particular no cytokine release syndrome (CRS) or GVHD of any grade. We have evaluated seven of the patients. At 6-week evaluation, per Lugano criteria, two patients have had a complete response (one shown in Figure 1) and three have had a partial response (overall response rate of 71%). CD30.CAR EBVSTs were detectable for 1 week in peripheral blood, but there was no evidence of expansion. We are analyzing tumor samples for CD30.CAR EBVSTs, and will continue to assess the safety, efficacy and durability of these responses. Thus banked CD30.CAR EBVSTs can safely be given to allogeneic recipients and may cause significant tumor responses including complete remissions. These cells may be a suitable platform for other "off-the-shelf" CAR-T cell therapies. Figure 1 Figure 1. Disclosures Quach: Tessa Therapeutics: Research Funding. Ramos: Athenex: Research Funding; Novartis: Consultancy; Genentech: Consultancy; Tessa Therapeutics: Patents & Royalties, Research Funding. Grilley: Allovir: Current equity holder in publicly-traded company, Other: Leadership; QB Regulatory Consulting: Other: Ownership, project management support, Research Funding; Marker: Consultancy, Other: Regulatory and project management support. Brenner: Athenex: Membership on an entity's Board of Directors or advisory committees; Turnstone Biologics: Membership on an entity's Board of Directors or advisory committees; TScan Therapeutics: Membership on an entity's Board of Directors or advisory committees; Coya Therapeutics: Membership on an entity's Board of Directors or advisory committees; CellGenix GmbH: Membership on an entity's Board of Directors or advisory committees; Walking Fish Therapeutics: Membership on an entity's Board of Directors or advisory committees; Poseida Therapeutics: Membership on an entity's Board of Directors or advisory committees; Onkimmune: Membership on an entity's Board of Directors or advisory committees; Memgen: Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees; Bellicum Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Allogene: Membership on an entity's Board of Directors or advisory committees; Abintus: Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Other: Founder; Allovir: Current equity holder in publicly-traded company; Marker Therapeutics: Current equity holder in publicly-traded company. Heslop: Kiadis: Membership on an entity's Board of Directors or advisory committees; Allovir: Current equity holder in publicly-traded company; Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: 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; Kuur Therapeutics: Research Funding; Marker Therapeutics: Current equity holder in publicly-traded company; GSK: Membership on an entity's Board of Directors or advisory committees; Fresh Wind Biotherapies: Membership on an entity's Board of Directors or advisory committees. Rouce: Tessa Therapeutics: Research Funding; Pfizer: Consultancy; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lapteva: Tessa Therapeutics: Consultancy. Rooney: Tessa: Membership on an entity's Board of Directors or advisory committees, Research Funding; Marker Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Allovir: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 6-7
Author(s):  
Nina Shah ◽  
Dieter Ayers ◽  
Faith E. Davies ◽  
Shannon Cope ◽  
Ali Mojebi ◽  
...  

Introduction: Patients with relapsed and refractory multiple myeloma (RRMM) who are triple-class exposed to immunomodulatory drugs, proteasome inhibitors, and anti-CD38 antibodies have poor clinical outcomes. Idecabtagene vicleucel (ide-cel, bb2121) is a chimeric antigen receptor (CAR) T cell therapy under development for this patient population. The ide-cel construct includes a single-chain variable fragment anti-B-cell maturation antigen (BCMA) recognition domain, a CD3-zeta activation domain, and a 4-1BB T-cell activation domain. An ongoing, single-arm phase 2 study to evaluate the efficacy and safety of ide-cel in RRMM (KarMMa; NCT03361748) reported an overall response rate (ORR) of 73%, a complete response rate of 31%, a median duration of response of 10.6 months, median progression-free survival (PFS) of 8.8 months, and a median overall survival (OS) of 19.4 months in the treated population (Munshi NC, et al. J Clin Oncol 2020;38:8503). A systematic literature review of published efficacy data for triple-class-exposed patients with RRMM identified MAMMOTH, a large, retrospective observational study (Gandhi UH, et al. Leukemia 2019;33:2266-2275). Patients in both MAMMOTH and KarMMa were triple-class exposed. In MAMMOTH, patients received a variety of regimens corresponding to conventional care (CC) following progression on anti-CD38 antibodies. This analysis aimed to compare efficacy outcomes observed with ide-cel treatment in KarMMa and CC in MAMMOTH. Methods: Individual patient-level data (IPD) with a median follow-up of 13.3 months were available for KarMMa (data cutoff January 14, 2020) while study-level data were available for MAMMOTH. Unanchored matching-adjusted indirect comparisons (MAICs) were conducted to compare efficacy outcomes from the 2 studies. These analyses were performed on data from 128 patients who received ide-cel (target dose 150, 300, or 450 × 106 CAR+ T cells) in KarMMa, and 249 patients who received CC therapies after progression on an anti-CD38 antibody in MAMMOTH. IPD from MAMMOTH were reconstructed based on published Kaplan-Meier curves for time-to-event outcomes. The most relevant differences in patient characteristics between the studies were identified for adjustment based on published literature and clinical expertise. These included the number of prior lines of treatment, proportion of patients refractory to specific prior treatments, and time since diagnosis. Propensity score models were used to weight the treated population from KarMMa to match the baseline characteristics of treated patients in MAMMOTH in order to predict outcomes for ide-cel in a population corresponding to those evaluated in MAMMOTH. The effective sample size (ESS) was calculated as a measure of the amount of overlap between the study populations included in the MAIC. Odds ratios (ORs) were calculated for ORR using weighted logistic regression models. Hazard ratios (HRs) were calculated for PFS and OS using weighted Cox proportional hazards models. Results: Ide-cel was associated with a significantly higher ORR compared with CC in a population matched to the treated MAMMOTH population (OR 5.11, 95% confidence interval [CI] 2.92-8.94, P &lt; 0.001) (Table 1). Similarly, ide-cel significantly extended PFS (HR 0.55, 95% CI 0.42-0.73, P &lt; 0.001) and OS (HR 0.36, 95% CI 0.24-0.54, P &lt; 0.001) versus CC. Results were generally consistent for patients in the ITT population and those who received the target dose of 450 × 106 CAR+ T cells who experienced efficacy gains exceeding those receiving lower target doses. In MAMMOTH, the individual CC regimens involving targeted therapies (carfilzomib, daratumumab, and elotuzumab) were associated with a median OS of between 8.3 and 12.7 months. The weighted median OS times for ide-cel are consistently longer than those associated with the individual CC regimens in MAMMOTH (Table 2), similar to the results for the overall treated population. Limitations of this inter-study comparison include a tighter window of OS evaluation in the ide-cel arm, which may have underestimated the true difference. More broadly, there is also a risk of bias given limited reporting on potential confounders. Conclusion: Ide-cel provides clinically and statistically significant efficacy benefits over current CC, including combination regimens involving targeted agents. Disclosures Shah: GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Ayers:PRECISIONheor: Current Employment. Davies:Adaptive Biotech: Honoraria; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: 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; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cope:PRECISIONheor: Current Employment. Mojebi:PRECISIONheor: Current Employment. Parikh:BMS: Current Employment, Current equity holder in publicly-traded company. Dhanda:BMS: Current Employment, Current equity holder in publicly-traded company. Hari:Amgen: Consultancy; Janssen: Consultancy; GSK: Consultancy; Takeda: Consultancy; Incyte Corporation: Consultancy; BMS: Consultancy. Patel:BMS: Current Employment. Huang:BMS: Current Employment, Current equity holder in publicly-traded company. Hege:BMS: Current Employment, Current equity holder in publicly-traded company, Other: Travel, accommodations, expenses, Patents & Royalties: Numerous, Research Funding; Mersana Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Arcus Biosciences: Divested equity in a private or publicly-traded company in the past 24 months. Dhanasiri:BMS: Current Employment, Current equity holder in publicly-traded company.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 904-904
Author(s):  
Dina Stroopinsky ◽  
Anita G. Koshy ◽  
Jessica J. Liegel ◽  
Myrna Nahas ◽  
Giulia Cheloni ◽  
...  

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.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 902-902
Author(s):  
Nicola C Maciocia ◽  
Amy Burley ◽  
Francesco Nannini ◽  
Patrycja Wawrzyniecka ◽  
Margarida Neves ◽  
...  

Abstract CAR-T cell therapy against CD19 has changed the treatment landscape in relapsed/refractory (r/r) B-ALL. R/r T-ALL has a dismal prognosis, with an unmet need for effective targeted therapies. Several unique challenges mean that CAR-T cell therapy has yet to be successfully translated to T-ALL. Most strategies have targeted pan-T cell antigens (CD7, CD5) but these are limited by T cell aplasia and fratricide, requiring elimination of CAR-T antigen surface expression during manufacture. An ideal target would be exclusively or largely confined to the malignant T cell component but published examples of these (CD1a and TRBC1) are expressed in only minor T-ALL subsets. We previously showed that CD21 is expressed in a NOTCH-dependent manner in T-ALL (Leukemia. 2013, 27:650) and have developed it as a potential immunotherapy target, being primarily expressed on normal B cells, with minimal expression on mature T cells. 70% of human T-ALL cell lines (9/16) expressed surface CD21 by flow cytometry (FACS), with a median antigen density in positive lines of 2545/cell. In primary T-ALL, 57% of presentation samples (n=58) expressed CD21 (median antigen density 1168/cell). 45% of relapse (n=11) and 20% of primary refractory cases (n=30) expressed CD21, with a similar antigen density to presentation samples. CD21 positivity varied by maturational stage, with highest expression in cortical T-ALL (80% of cases) followed by pre-T (72%), mature (67%), ETP (25%) and pro-T (17%). Healthy donor blood (n=14) showed CD21 expression limited to B cells and a low proportion (11%) of T cells (10-fold lower intensity v B cells, 316 antigens/cell). T cell CD21 expression was not up-regulated upon activation with CD3/CD28 antibodies (n=6) and was not associated with markers of differentiation/exhaustion. To target CD21, DNA gene-gun vaccination of rats with a plasmid encoding full-length CD21, followed by phage display was performed and multiple anti-CD21 scFvs isolated. These were cloned into 4-1BBζ CARs and expressed in primary T cells but failed to kill or secrete cytokines in response to CD21+ SupT1 cells. CD21 is a bulky molecule, with 15/16 sushi repeats in the extracellular domain. All isolated scFvs were found to bind membrane-distal domains. We hypothesized that ineffective signalling due to inadequate synapse formation was responsible for poor performance of anti-CD21 CAR-T, and that binders to membrane-proximal epitopes would signal more efficiently. We re-vaccinated rats with the first 5 sushi repeats of CD21 and generated a library of binders which bound CD21 at this membrane-proximal region. Multiple candidate binders expressed as CARs were functional, with cytotoxicity and interferon-γ secretion in response to CD21+ target cells. However, non-specific background cytokine secretion was seen against CD21 negative cells, and no IL-2 secretion was seen. Re-cloning binders into a fragment antigen binding (Fab)-CAR architecture yielded constructs capable of specific cytotoxicity, IFN-γ and IL2 secretion against a CD21+ cell line but not its CD21 negative counterpart (n=6). Our lead anti-CD21 candidate CAR specifically proliferated in vitro, without fratricide or premature exhaustion/ differentiation, and was active against low-density CD21-positive cell lines (n=3) and primary cells from 2 T-ALL patients. Improved functionality of Fab v scFv-based CAR was not driven by higher affinity binding or CAR surface expression. We tested anti-CD21 CAR in murine models of T-ALL. NSG mice were injected with SupT1-luciferase cells and treated with aCD19 or aCD21 CAR-T on day +5. At 2 weeks post treatment, markedly lower disease burden was seen in CD21 CAR-T v CD19 recipients by bioluminescence imaging (median radiance 71700 v 790000 p=0.0079). Further, we injected primary T-ALL blasts in another cohort, treating with aCD19 or aCD21 CAR-T on D+20. Serial bleeds from day 27 post CAR-T showed tumour control in aCD21 CAR treated mice (p=0.024) with an overall survival advantage (median OS 44 days vs undefined, HR = 19.8, p = 0.0069, n=4/group). In summary, we propose CD21 as a novel target for CAR-T cell therapy in T-ALL. Its expression is largely restricted to the malignant T cell compartment, overcoming issues with fratricide and on-target off-tumour effects seen in many T-ALL CAR-T strategies to date. Despite the complexity of the target, we have successfully generated an aCD21 CAR that is functional both in vitro and in vivo. Disclosures Maciocia: Autolus: Current equity holder in publicly-traded company. Onuoha: Autolus: Ended employment in the past 24 months. Khwaja: Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Maciocia: Autolus: Current equity holder in publicly-traded company, Research Funding. Pule: Autolus: Current Employment, Current equity holder in publicly-traded company.


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