scholarly journals Allogeneic CAR-T Cells: More than Ease of Access?

Cells ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 155 ◽  
Author(s):  
Charlotte Graham ◽  
Agnieszka Jozwik ◽  
Andrea Pepper ◽  
Reuben Benjamin

Patient derived anti-CD19 chimeric antigen receptor-T (CAR-T) cells are a powerful tool in achieving a complete remission in a range of B-cell malignancies, most notably B-acute lymphoblastic leukaemia (B-ALL) and diffuse large B-cell lymphoma (DLBCL). However, there are limitations, including inability to manufacture CAR-T cells from the patient’s own T cells, disease progression and death prior to return of engineered cells. T cell dysfunction is known to occur in cancer patients, and several groups have recently described differences in CAR-T cells generated from chronic lymphocytic leukaemia (CLL) patients compared with those from a healthy donor. This is thought to contribute to the low response rate in this disease group. Healthy donor, gene-edited CAR-T cells which do not require human leucocyte antigen (HLA) matching have the potential to provide an ‘off the shelf’ product, overcoming the manufacturing difficulties of producing CAR-T cells for each individual patient. They may also provide a more functional, potent product for malignancies such as CLL, where T cell dysfunction is common and frequently cannot be fully reversed during the manufacturing process. Here we review the potential benefits and obstacles for healthy donor, allogeneic CAR-T cells.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 681-681
Author(s):  
McKensie Collins ◽  
Weimin Kong ◽  
Inyoung Jung ◽  
Meng Wang ◽  
Stefan M Lundh ◽  
...  

Introduction: Chronic Lymphocytic Leukemia (CLL) is a CD19+ B-cell malignancy that accounts for approximately 25% of adult leukemia diagnoses in the developed world. While conventional therapies have some efficacy, there are few curative therapeutic options and many patients ultimately progress to relapsed or refractory disease. CD19-targeting chimeric antigen receptor (CAR) T cell therapy has provided some hope, but induces complete remission in only 26% of patients. This suboptimal response rate is believed to be due to T cell dysfunction and immune-suppression by CLL cells, the mechanisms of which are poorly understood. Results: To understand the causes of CAR T cell dysfunction in CLL we investigated the defects that CLL cells induced in normal donor CD19-targeting CAR T cells. CAR T cells were repeatedly stimulated at 5-day intervals with either primary CLL cells from patients or a CD19-expressing control cell line (aAPC). Repeat stimulation of CAR T cells with aAPCs resulted in 5.36 ± .94 population doublings after three stimulations, whereas CLL cells only evoked 2.39 ± .92 population doublings. We performed phenotyping, proliferation analysis, and cytokine analysis of stimulated CAR T cells. CLL-stimulated T cells appeared un-activated, with low levels of PD-1, LAG3, and TIM3, low levels of cytokine production, and a high proportion of non-cycling cells as measured by Ki67 staining. We first hypothesized that CLL cells induce an altered epigenetic program that prevents effector function and is stabilized by successive stimulations. To test this, we stimulated CAR T cells with CLL cells or aAPCs as indicated in Fig. 1A. CLL-stimulated CAR T cells failed to proliferate or produce cytokines, but subsequent stimulation with aAPCs rescued these functions (Fig. 1B). Further, CLL-stimulated CAR T cells did not differentiate, suggesting that CLL cells do not induce stable defects but rather insufficiently activate CAR T cells (Fig. 1C). These cells also appeared un-activated as indicated by low levels of PD-1 and Ki67. We then used flow cytometry to assess expression of costimulatory and inhibitory molecules on the primary CLL samples. We found that the levels of co-stimulatory and adhesion molecules, namely CD80/CD86 and CD54/CD58 respectively were found at low frequencies, and where present were expressed at low levels. This suggested that one mechanism behind the lack of CAR T cell effector responses may be that a lack of co-stimulation prevents proper CAR T cell targeting of these cells. Towards this, we incubated CLL cells with a murine fibroblast line expressing CD40 ligand for 24 hours with IL-4 to activate the CLL cells. We found that this activation significantly increased expression of CD80, CD86, CD54, and CD58 on the CLL cells. We then used these cells to stimulate CAR T cells in our re-stimulation assay and found that CAR T cells were able to proliferate in response to these activated CLLs (Fig. 1D). In addition, CAR T cells stimulated with activated CLL cells formed more cell-to-cell conjugates than those stimulated with un-activated CLL cells. These data suggest not only that insufficient activation of CAR T cells may be responsible for the poor response rates to CAR T cell therapy in CLL, but also implicate a need for additional co-stimulation in this CAR T cell setting. Another contributing factor may be immune suppression by CLL cells. To determine if CLL cells are immune-suppressive, we used a co-culture assay to stimulate CAR T cells with aAPCs and CLL cells mixed at known ratios. Interestingly, all mixed cultures proliferated similarly, suggesting that CLL cells did not prevent T cell activation in the presence of a strong activation signal. We also found that CLL cells are responsive to IL-2, as addition of this cytokine to culture media prolongs survival of CLL cells out to 10 days depending on the dose. This suggests that CLL cells express a functional IL-2 receptor and may be taking up IL-2 from the culture media, further impairing T cell activation. In support of this, supplementing IL-2 into our CLL/CAR T cell co-cultures rescued T cell proliferative capacity. Taken together, these data suggest that T cell dysfunction in CLL is the result of insufficient activation rather than true functional defects. Disclosures June: Novartis: Research Funding; Tmunity: Other: scientific founder, for which he has founders stock but no income, Patents & Royalties. Melenhorst:National Institutes of Health: Research Funding; Parker Institute for Cancer Immunotherapy: Research Funding; Novartis: Research Funding, Speakers Bureau; IASO Biotherapeutics, Co: Consultancy; Simcere of America, Inc: Consultancy; Shanghai Unicar Therapy, Co: Consultancy; Colorado Clinical and Translational Sciences Institute: Membership on an entity's Board of Directors or advisory committees; Genentech: Speakers Bureau; Stand Up to Cancer: Research Funding; Incyte: Research Funding.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1851-1851 ◽  
Author(s):  
Diogo Gomes da Silva ◽  
Malini Mukherjee ◽  
Madhuwanti Srinivasan ◽  
Olga Dakhova ◽  
Hao Liu ◽  
...  

Abstract Although adoptive transfer of T cells with second-generation CD19-specific CARs containing CD28 or 4-1BB costimulatory endodomains shows remarkable clinical efficacy against B cell malignancies, the optimal choice of costimulatory domains in these and other CARs remains controversial. Depending on the precise CAR structure and specificity, individual endodomains may be associated with deleterious ligand-independent tonic signaling in the transduced T cell. Long et al. (Nat Med 2015) established the CD28 co-stimulatory endodomain can have a toxic tonic signaling effect, but it is unclear if tonic 4-1BB signaling may have deleterious consequences as well, and if such effects can be reversed. We therefore modeled tonic CAR signaling in T cells by transducing them with gammaretroviral vectors expressing 2nd-generation CD19.CAR constructs containing either the CD28 or 4-1BB costimulatory endodomain (in addition to the CD3-ζ chain endodomain). Compared to CAR-T cells with the CD28 endodomain alone, those with 4-1BB alone expanded 70% more slowly following transduction. Impaired expansion of 4-1BB CD19.CAR-T cells was coupled with a 4-fold increase in apoptosis and a gradual downregulation of CAR expression, and was a consequence of 4-1BB-associated tonic TRAF2-dependent signaling, leading to activation of NF-κB, upregulation of Fas and augmented Fas-dependent activation-induced T cell death (AICD). Moreover, expression of 4-1BB CAR from a gammaretroviral vector increased tonic signaling through a self-amplifying/positive feedback effect on the retroviral LTR promoter. Because of the toxicity of 4-1BB in our gammaretroviral CAR.CD19 construct (manifest by delayed expansion and increased apoptosis) we could not directly compare the in vivo fate of T cells expressing CAR.CD19 4-1BB with that of co-administered CAR.CD19 CD28 T cells in patients with lymphoma. We found, however, that the adverse effects of tonic 4-1BB costimulation could be overcome in a 3rd-generation CAR.CD19 vector, containing both CD28 and 4-1BB costimulatory molecules in tandem. We thus compared the fate of a 3rd-generation vector containing both CD28 and 4-1BB costimulatory domains with that of a 2nd-generation vector containing CD28 alone. Six patients with refractory/relapsed diffuse large B-cell lymphoma received 2 cell populations, one expressing 2nd and one expressing 3rd generation vectors. To determine whether CD28 alone was optimal (which would suggest 4-1BB is antagonistic) or whether 4-1BB had an additive or synergistic effect contributing to superior persistence and expansion of the CD28-41BB combination, patients were simultaneously infused with 1-20×106 of both 2nd and 3rd generation CAR+ T cells/m2 48-72 hours after lymphodepletion with cyclophosphamide (500 mg/m2/d) and fludarabine (30 mg/m2/d) × 3. Persistence of infused T cells was assessed in blood by CD19.CAR qPCR assays specific for each CAR. Molecular signals peaked approximately 2 weeks post infusion, remaining detectable for up to 6 months. The 3rd-generation CAR-T cells had a mean 23-fold (range 1.1 to 109-fold) higher expansion than 2nd-generation CAR-T cells and correspondingly longer persistence. Two patients had grade 2 cytokine release syndrome, with elevation of proinflammatory cytokines, including IL-6, at the time of peak expansion of T cells. Of the 5 patients evaluable for response, 2 entered complete remission (the longest ongoing for 9 months), 1 has had continued complete remission after autologous stem cell transplantation, 1 had a partial response, and 1 progressed. In conclusion, our data indicate that infusion of T cells carrying a CD19.CAR containing CD28 and 4-1BB endodomains is safe and can have efficacy at every dose level tested. Additionally, in a side-by-side comparison, the 3rdgeneration vector produced greater in vivo expansion and persistence than an otherwise identical CAR-T cell population with CD28 alone. Disclosures Rooney: Cell Medica: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Viracyte: Equity Ownership. Heslop:Celgene: Patents & Royalties, Research Funding; Chimerix: Other: Endpoint adjudication committee; Viracyte: Equity Ownership; Cell Medica: Patents & Royalties: Licensing agreement EBV-specific T cells.


2020 ◽  
Author(s):  
Mostapha Benhenda

AbstractChimeric antigen receptor (CAR) T cells still have limited effects in cancer, and especially in solid tumors, due to T cell dysfunction and exhaustion. CAR T cells overexpressing c-Jun (JUN CAR T cells) have been introduced to solve this problem. In this paper, we analyze JUN CAR T cells scRNA-seq data in solid tumors, by applying a genome-wide signature of T cell dysfunction, TID. This signature comes from the bulk RNA-seq signature TIDE, introduced to predict immune checkpoint inhibitor response. Our analysis confirms that on average, JUN CAR T cells are less dysfunctional than non-JUN CAR T cells. However, it also shows heterogeneity within JUN CAR T cells, which brings uncertainty about possible tumor resistance. We conclude that genome-wide dysfunction signature TID helps de-risking CAR T cell therapy for solid tumors.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2800-2800
Author(s):  
Michael Olson ◽  
Tim Luetkens ◽  
Fiorella Iglesias ◽  
Sabarinath Radhakrishnan ◽  
Jennie Y. Law ◽  
...  

Abstract B cell lymphoma is the most common hematologic malignancy in the United States. Although treatment options have greatly improved in the past several decades, outcomes for patients with relapsed B cell lymphoma remain poor. Chimeric antigen receptor (CAR) T cells have recently entered the clinic with promise to address the gap in effective therapies for patients relapsed B cell lymphoma. However, antigen loss and poor CAR T cell persistence has been shown to drive resistance to the widely approved CD19-targeted CAR in some patients, demonstrating the need for additional therapies. Here, we demonstrate CD229-targeted CAR T cell therapy as a promising option for the treatment of relapsed B cell lymphoma, addressing an important group of patients with typically poor outcomes. CD229 is an immune-modulating receptor expressed on the surface of B cells that we recently found to be highly expressed in the plasma cell neoplasm multiple myeloma (Radhakrishnan et al. 2020). We utilized semi-quantitative PCR and flow cytometry to assess whether CD229 is also expressed on malignant B cells earlier in development as found in B cell lymphoma. Expression analysis revealed the presence of CD229 in a panel of 11 B cell lymphoma cell lines and 45 primary B cell lymphoma samples comprising several subsets of disease including aggressive B cell lymphomas such as diffuse large B cell lymphoma (DLBCL), mantle cell lymphoma (MCL) and Burkitt lymphoma as well as indolent subtypes of B cell lymphoma including chronic lymphoblastic leukemia (CLL) and follicular lymphoma. Of note, CD229 was found to be overexpressed on primary B cell lymphoma cells when compared to autologous normal B cells. Given the high levels of CD229 expression throughout all B cell lymphoma subtypes analyzed, we generated CD229 CAR T cells in order to determine whether CAR T cell therapy is an effective way to target CD229 expressing B cell lymphoma cells. CD229 CAR T cells exhibited robust cytotoxicity when cocultured with B cell lymphoma cell lines and primary samples characterized by significant production of TH1 cytokines IL-2, TNF and IFNγ and rapid loss of B cell lymphoma cell viability when compared to control CAR T cells lacking an antigen binding scFv domain (∆scFv CAR T cells). In vivo analysis revealed effective tumor control in NSG mice carrying B cell lymphoma cell lines JeKo-1 (MCL) and DB (DLBCL) when treated with CD229 CAR T cells versus ∆scFv CAR T cells. Finally, we sought to determine the efficacy of CD229 CAR T cells in the context of CD19 CAR T cell therapy relapse. Here, a 71-year-old patient with CLL had an initial response when treated with CD19 CAR T cells but quickly relapsed only 2 months after treatment. Malignant cells from the CLL patient retained CD229 expression as identified by flow cytometry and an ex vivo coculture with CD229 CAR T cells revealed robust killing of CLL cells by CD229 CAR T cells. Transfer of antigen from target cell to CAR T cell by trogocytosis was recently suggested to drive relapse following CAR T cell therapy by decreasing antigen on tumor cells and promoting CAR T cell fratricide (Hamieh et al. 2019). We cocultured CD19 and CD229 CAR T cells with primary CLL cells and assessed CD19 and CD229 expression as well as CAR T cell viability by flow cytometry. In contrast with CD19 CAR T cells, CD229 CARs did not strip their target antigen from the surface of CLL cells. The transfer of CD19 from CLL cells to CD19 CAR T cells resulted in poor CAR T cell viability while CD229 CAR T cell viability remained high following coculture. In summary, we demonstrate that CD229 is a promising therapeutic target in B cell lymphoma due to its high levels of expression throughout many subtypes of disease. CD229 CAR T cells effectively kill B cell lymphoma cells in vitro and control growth of aggressive B cell lymphomas in vivo. Finally, CD229 CAR T cells are effective against primary CLL cells from patients that have relapsed from CD19 CAR T cell therapy and do no exhibit antigen loss by trogocytosis. Taken together, these data suggest that CD229 CAR T cell therapy may be a promising option to address the poor outcomes for patients with relapsed B cell lymphoma. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Vol 5 (19) ◽  
pp. 3789-3793
Author(s):  
Susanne Jung ◽  
Jochen Greiner ◽  
Stephanie von Harsdorf ◽  
Pavle Popovic ◽  
Roland Moll ◽  
...  

Abstract Treatment with CD19-directed (CAR) T cells has evolved as a standard of care for multiply relapsed or refractory large B-cell lymphoma (r/r LBCL). A common side effect of this treatment is the immune effector cell–associated neurotoxicity syndrome (ICANS). Severe ICANS can occur in up to 30% to 40% of patients treated with axicabtagene-ciloleucel (axi-cel), usually within the first 4 weeks after administration of the dose and usually responding well to steroids. We describe a case of progressive central neurotoxicity occurring 9 months after axi-cel infusion in a patient with r/r LBCL who had undergone a prior allogeneic hematopoietic cell transplant. Despite extensive systemic and intrathecal immunosuppression, neurological deterioration was inexorable and eventually fatal within 5 months. High CAR T-cell DNA copy numbers and elevated levels of interleukin-1 (IL-1) and IL-6 were found in the cerebral spinal fluid as clinical symptoms emerged, and CAR T-cell brain infiltration was observed on autopsy, suggesting that CAR T cells played a major pathogenetic role. This case of unexpected, devastating, late neurotoxicity warrants intensified investigation of neurological off-target effects of CD19-directed CAR T cells and highlights the need for continuous monitoring for late toxicities in this vulnerable patient population.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ulrich Blache ◽  
Ronald Weiss ◽  
Andreas Boldt ◽  
Michael Kapinsky ◽  
André-René Blaudszun ◽  
...  

Adoptive immunotherapy using chimeric antigen receptor (CAR)-T cells has achieved successful remissions in refractory B-cell leukemia and B-cell lymphomas. In order to estimate both success and severe side effects of CAR-T cell therapies, longitudinal monitoring of the patient’s immune system including CAR-T cells is desirable to accompany clinical staging. To conduct research on the fate and immunological impact of infused CAR-T cells, we established standardized 13-colour/15-parameter flow cytometry assays that are suitable to characterize immune cell subpopulations in the peripheral blood during CAR-T cell treatment. The respective staining technology is based on pre-formulated dry antibody panels in a uniform format. Additionally, further antibodies of choice can be added to address specific clinical or research questions. We designed panels for the anti-CD19 CAR-T therapy and, as a proof of concept, we assessed a healthy individual and three B-cell lymphoma patients treated with anti-CD19 CAR-T cells. We analyzed the presence of anti-CD19 CAR-T cells as well as residual CD19+ B cells, the activation status of the T-cell compartment, the expression of co-stimulatory signaling molecules and cytotoxic agents such as perforin and granzyme B. In summary, this work introduces standardized and modular flow cytometry assays for CAR-T cell clinical research, which could also be adapted in the future as quality controls during the CAR-T cell manufacturing process.


2021 ◽  
Vol 11 ◽  
Author(s):  
Limin Xing ◽  
Yihao Wang ◽  
Hui Liu ◽  
Shan Gao ◽  
Qing Shao ◽  
...  

Chimeric antigen receptor T (CAR-T) cells show good efficacy in the treatment of relapsed and refractory B-cell tumors, such as acute B-cell leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). The main toxicities of CAR-T include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cytopenia, and severe infection. It is still very difficult for CAR-T to kill tumor cells to the maximum extent and avoid damaging normal organs. Here, we report a case of DLBCL with persistent grade 4 thrombocytopenia and severe platelet transfusion dependence treated with CD19 CAR-T cells. We used sirolimus to inhibit the sustained activation of CAR-T cells and restore normal bone marrow hematopoiesis and peripheral blood cells. Moreover, sirolimus treatment did not affect the short-term efficacy of CAR-T cells, and DLBCL was in complete remission at the end of follow-up. In conclusion, sirolimus can represent a new strategy for the management of CAR-T cell therapy-related toxicity, including but not limited to hematotoxicity. However, further controlled clinical studies are required to confirm these findings.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3012-3012 ◽  
Author(s):  
Kathryn Cappell ◽  
Richard Mark Sherry ◽  
James C. Yang ◽  
Stephanie L. Goff ◽  
Danielle Vanasse ◽  
...  

3012 Background: T cells expressing anti-CD19 chimeric antigen receptors (CARs) can cause complete remissions of relapsed lymphoma. We conducted the first clinical trial of anti-CD19 CAR T cells to show responses against lymphoma. This CAR was later developed as axicabtagene ciloleucel. Here, we aimed to assess the long-term durability of remissions and the long-term adverse effects after anti-CD19 CAR T-cell therapy. Methods: Between 2009 and 2015, we treated 43 patients with anti-CD19 CAR T cells preceded by conditioning chemotherapy of cyclophosphamide plus fludarabine (NCT00924326). Three patients were re-treated for a total of 46 CAR T-cell treatments. Twenty-eight patients had aggressive lymphoma (diffuse large B-cell lymphoma or primary mediastinal B cell lymphoma), eight patients had low-grade lymphoma (five with follicular lymphoma and 1 each with splenic marginal zone lymphoma, mantle cell lymphoma, and unspecified low-grade non-Hodgkin lymphoma), and seven patients had chronic lymphocytic leukemia (CLL). Patients were treated in three cohorts that differed in the CAR T-cell production process and conditioning chemotherapy dose. Results: Of the 43 treated patients, 63% had chemotherapy-refractory lymphoma. Patients had received a median of 4 previous lines of therapy. The median CAR+ T cell dose per kilogram was 2X10^6. The overall remission rate was 76% with 54% complete remissions (CR) and 22% partial remissions (PR). Patients with CR had higher median peak blood CAR levels (86 CAR+ cells/µL) than those who did not have CR (16 CAR+ cells/µL, P= 0.0041). Long-term adverse effects were rare except for B-cell depletion and hypogammaglobulinemia, which both improved over time. Conclusions: This is the longest follow-up study of patients who received anti-CD19 CAR T cells. Anti-CD19 CAR T cells cause highly durable remissions of relapsed B-cell lymphoma and CLL, and long-term adverse effects of anti-CD19 CAR T cells were rare and usually mild. Clinical trial information: NCT00924326 . [Table: see text]


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A115-A115
Author(s):  
Anthony Battram ◽  
Mireia Bachiller ◽  
Álvaro Urbano-Ispizua ◽  
Beatriz Martin-Antonio

BackgroundChimeric antigen receptor-T (CAR-T) cells that target B cell maturation antigen (BCMA-CARs) have emerged as a promising treatment for multiple myeloma (MM). Despite impressive initial responses to BCMA-CAR therapy in clinical trials, relapse is common, signifying a need to improve the in vivo efficacy and persistence of BCMA-CARs.1 The development of unfavourable differentiation or T cell dysfunction, such as exhaustion and senescence, during the ex vivo expansion of the BCMA-CARs could be limiting their therapeutic potential. For CD19-directed CARs, reduced dysfunction and differentiation and improved anti-tumour responses were achieved by expanding the cells with IL-15 instead of IL-2.2 Therefore, in this study, our aim was to determine whether expanding BCMA-CARs with IL-15 or IL-15/IL-7 instead of IL-2 alters their levels of exhaustion, senescence, differentiation and activity.MethodsT cells stimulated with anti-CD3/anti-CD28-coated beads were supplemented with IL-2, IL-15, IL-15 + IL-7 or no cytokine and transduced with ARI2h, a BCMA-CAR with a 4-1BB co-stimulatory domain produced at our institution.3 Expanded BCMA-CARs were analysed by flow cytometry for markers of T cell dysfunction, or challenged with MM cell line ARP-1 and then tested for cytokine production, cytotoxic ability and activation signals.ResultsBCMA-CARs cultured in IL-15 or IL-15/IL-7 expanded similarly to those grown in IL-2, with comparable CAR transduction efficiencies, CD4:CD8 ratios and proliferation rates. BCMA-CARs grown in IL-15 had low expression of exhaustion marker LAG-3 and high expression of the costimulatory molecule CD27, which is important for T cell survival and persistence, when compared to BCMA-CARs cultured in IL-2. Moreover, BCMA-CARs grown solely in IL-15 were less differentiated than those supplemented with IL-7, and had higher expression of stem cell memory marker CXCR3 within the naïve population than those expanded with IL-2. When challenged with MM cell line ARP-1, IL-15-grown BCMA-CARs upregulated activation marker CD69, exhibited strong cytotoxicity and robust production of IFNγ and IL-2. However, in comparison to BCMA-CARs expanded in IL-2 or IL-15/IL-7, those grown with IL-15 had lower mTORC1 activity and p38 MAPK phosphorylation when activated by ARP-1 cells, suggesting differential regulation of key pathways for T cell metabolism and senescence, respectively.ConclusionsTo summarise, BCMA-CARs expanded with IL-15 alone exhibited the most favourable phenotype for therapeutic use compared those grown with IL-2 or IL-15/IL-7. Future experiments using murine MM models will be critical in understanding the in vivo benefits or drawbacks of culturing BCMA-CARs in IL-15 compared to IL-2 or IL-15/IL-7.Ethics ApprovalResearch involving human material was approved by the Ethical Committee of Clinical Research (Hospital Clinic, Barcelona). Peripheral blood T cells were obtained from healthy donors after informed consent in accordance with the Declaration of Helsinki.ReferencesRoex G, Feys T, Beguin Y, Kerre T, Poiré X, Lewalle P, et al. Chimeric Antigen Receptor-T-Cell Therapy for B-Cell Hematological Malignancies: An Update of the Pivotal Clinical Trial Data. Pharmaceutics [Internet]. 2020;12:1–15. Available from: http://www.ncbi.nlm.nih.gov/pubmed/32102267Alizadeh D, Wong RA, Yang X, Wang D, Pecoraro JR, Kuo CF, et al. IL15 enhances CAR-T cell antitumor activity by reducing mTORC1 activity and preserving their stem cell memory phenotype. Cancer Immunol Res 2019;7:759–72.Perez-Amill L, Suñe G, Antoñana-Vildosola A, Castella M, Najjar A, Bonet J, et al. Preclinical development of a humanized chimeric antigen receptor against B cell maturation antigen for multiple myeloma. Haematologica [Internet]. 2020; Available from: http://www.ncbi.nlm.nih.gov/pubmed/31919085


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 678-678 ◽  
Author(s):  
Pei-Hsuan Chen ◽  
Mikel Lipschitz ◽  
Kyle Wright ◽  
Philippe Armand ◽  
Caron A. Jacobson ◽  
...  

Abstract BACKGROUND: Axicabtagene ciloleucel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy that shows efficacy in patients with refractory diffuse large B-cell lymphoma (DLBCL), primary mediastinal B-cell lymphoma and transformed follicular lymphoma after failure of conventional therapy. However, the exact mechanism of anti-tumor immunity is poorly understood, in part due to the dearth of data on the events in the tumor micro-environment (TME) that occur upon exposure to CAR-T cells. We sought to quantify and characterize both CAR-T cells and non-CAR T cells within the TME of DLBCL using tissue biopsy samples collected in the ZUMA-1 multicenter trial of CAR-T cell therapy for patients with refractory DLBCL. METHODS: Tumor samples obtained from patients 5-30 days (median 10 days) after CAR-T infusion ("CAR-treated", n=14) and randomly-selected untreated ("untreated ", n=15) archival DLBCL tissue samples were analyzed by multiplex immunofluorescence using formalin-fixed, paraffin embedded tissue sections, with successive labeling by the primary antibodies KIP-1 and/or KIP-3 (recognizing separate CD19 CAR epitopes), PAX5, PD-1, CD4, and CD8, followed by secondary amplification and tyramide-conjugated fluorophores. For each case, at least 3 representative 20x fields of view were selected and imaged using a multispectral imaging platform. Two specific image analysis algorithms were designed to accurately identify CD4 and CD8 T cells and PAX5+ DLBCL cells simultaneously, then to threshold PD-1 and KIP-1/-3 by relative fluorescent units (RFU) in each phenotype. RESULTS: We identified CAR T-cells within the fixed biopsy samples of CAR-treated DLBCLs by immunostaining with CAR T-cell specific antibody KIP-1; at the timepoints analyzed, CAR T-cells comprised only a small minority of total T- cells (<2%) and included CD4+ and CD8+ T-cells. Immunostaining with a second antibody, KIP-3, validated the presence of CAR T-cells in these cases and confirmed the KIP-1 results. Expression of the T cell activation marker PD-1 was detected among majority of KIP-1+ cells. Further analysis that included KIP1-negative cells revealed that the percentage of CD8+ cells co-expressing PD-1 across all CD8+ cells was higher in the CAR-treated DLBCLs compared to the untreated DLBCLs (mean 50.1% vs 17.5%, p<0.0001 with unpaired t test ), indicating CD8 T cell activation within the tumor environment. In contrast, PD-1 positivity across CD4+ T cells were equivalent between the two groups (mean 21.8% vs 21.6%, ns with unpaired t test). The percentages of total, CD4+, and CD8+ T-cell populations in the TME were similar between the CAR-treated DLBCL and untreated biopsies. CONCLUSIONS: CD4+ and CD8+ CAR-T cells can be detected in CAR-treated DLBCL patient tissue biopsies by multiplex immunofluorescence. At the time points analyzed to date, CAR-T cells comprise only a small percentage of all T-cells (<2%) within the TME. However, the presence of gene marked T cells with downregulated CAR protein expression is also possible. The activation marker PD-1 is preferentially expressed by KIP-1-negative CD8+ T cells compared to CD4+ T cells in CAR-T treated DLBCLs relative to untreated DLBCLs. These data implicate preferential activation of CD8+ non-CAR "by-stander" T-cells in the post CAR-T TME, and the possible benefit of combining PD-1 blockade with CAR-T therapy in DLBCL. *PH.C and M.L share equal contribution. Disclosures Armand: Otsuka: Research Funding; Affimed: Consultancy, Research Funding; Pfizer: Consultancy; Infinity: Consultancy; Adaptive: Research Funding; Merck: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Roche: Research Funding; Tensha: Research Funding. Roberts:KITE: Employment. Rossi:KITE: Employment. Bot:KITE: Employment. Go:KITE: Employment. Rodig:Merck: Research Funding; Bristol Myers Squibb: Research Funding; Affimed: Research Funding; KITE: Research Funding.


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