scholarly journals Autologous culture model of nodal B-cell lymphoma identifies ex vivo determinants of response to bispecific antibodies

Author(s):  
Tobias Roider ◽  
Berit J. Brinkmann ◽  
Vladislav Kim ◽  
Mareike Knoll ◽  
Carolin Kolb ◽  
...  

Bispecific antibodies (BsAb) can induce long-term responses in refractory and relapsed B cell lymphoma patients. Nevertheless, response rates across patients are heterogenous and the factors determining quality and duration of responses are poorly understood. In order to identify key determinants of response to BsAb, we established a primary, autologous culture model allowing us to mimic treatment with CD3xCD19 and CD3xCD20 BsAb within the lymph node microenvironment ex vivo. T cell-mediated killing of lymphoma cells and proliferation of T cells varied significantly among patients but highly correlated between BsAb targeting CD20 or CD19. Ex vivo response to BsAb was significantly associated with expansion of T cells and secretion of effector molecules, such as granzyme B and perforin, but not with expression of T cell exhaustion (e.g. PD1, TIM3) or activation markers (e.g. CD25, CD69) or formation of intercellular contacts. In addition, we identified a distinct phenotype of regulatory T cells that was linked to ex vivo response independently from T cell frequency at baseline. High expression levels of Aiolos (IKZF1), ICOS and CXCR5 were positively associated with ex vivo response, whereas strong expression of Helios (IKZF2) had unfavorable impact on ex vivo response to BsAb. Furthermore, we demonstrated that lenalidomide, nivolumab and atezolizumab improved ex vivo response to BsAb by potentiating T cell effector functions. In summary, our ex vivo study identifies a distinct regulatory T cell phenotype as potential contributor to treatment failure of BsAb, and suggests drug combinations of high clinical relevance that could improve the efficacy of BsAb.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 391-391 ◽  
Author(s):  
Nicole Sunseri ◽  
Xiufen Chen ◽  
Noemie Wald ◽  
Julie Preillon ◽  
Sonali M. Smith ◽  
...  

Background: The PD-1/PD-L1 axis is a dominant cancer immune escape pathway, and PD-1 blockade therapy has greatly benefited patients with select solid tumors and lymphomas. Unfortunately, anti-PD-1 monotherapy has limited efficacy against relapsed/refractory (r/r) diffuse large B cell lymphoma (DLBCL) - a disease where new therapies are needed. Because numerous inhibitory checkpoint receptors have been implicated in driving tumor-specific T cell dysfunction, we hypothesized that combinatorial checkpoint blockade therapy (CBT) would enhance the activity of PD-1-based therapy in r/r DLBCL. T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is a recently identified co-inhibitory receptor expressed on dysfunctional tumor-infiltrating T cells. PD-1 and TIGIT co-blockade therapy has demonstrated impressive activity in pre-clinical solid tumor and myeloma models. However, the degree to which TIGIT is involved in mediating T cell suppression in DLBCL is not fully known. Methods: TIGIT expression on lymphoma-infiltrating T cells (LITs) from 18 fresh lymphoma samples was analyzed by flow cytometry. Multiplex IHC on tissue microarrays (TMAs) was also performed to investigate TIGIT expression in DLBCL samples. The syngeneic murine A20 B cell lymphoma model was employed to study: 1) the kinetics of TIGIT and other co-receptor expression on LITs, 2) the association of TIGIT expression with effector function among LITs, and 3) the effectiveness of anti-TIGIT mono- and combination CBT in mice with established A20 lymphomas. A20 lymphoma tumors were established in groups of Balb/c mice by subcutaneous (SQ) injections of 5 x 106 cells. Expression of TIGIT and other co-receptors in A20 LITs was examined by flow cytometry at various time points. Function of TIGIT+ LITs was assessed by examining cytokine production following ex vivo stimulation with PMA and ionomycin. To test the efficacy of TIGIT blockade, mice received intraperitoneal injections of anti-TIGIT, anti-PD-1, anti-4-1BB, or combinations of these antibodies. Treatments began once tumors reached a diameter of 10 mm and were continued every 3 days for 5 doses. Tumor growth was monitored and compared to that in A20-bearing mice treated with isotype control antibodies. In some experiments, mice that achieved complete tumor rejection following single or dual CBT were re-challenged with A20 cells to investigate immunological memory responses. Results: Across a variety of human lymphomas, flow cytometric analysis revealed that TIGIT was broadly upregulated on LITs, including regulatory T cells and conventional CD4+and CD8+ T cells (Figure A and B). TIGIT expression on LITs in DLBCL was particularly high. Nearly all TIGIT+ LITs were also PD-1+, suggesting that these receptors co-orchestrate a T cell dysfunctional state in the lymphoma environment. Multiplex immunofluorescence staining of DLBCL samples demonstrated that TIGIT was most highly expressed on CD8+ T cells and that TIGIT+ T cells tended to be localized near, and in some cases, surrounding CD20+ lymphoma cells. Consistent with observations in human lymphomas, LITs isolated from murine A20 lymphoma commonly co-expressed TIGIT and PD-1, and the degree of expression correlated directly with tumor volume. This correlation was also present for other co-receptors, including 4-1BB, TIM3, and CTLA-4. Ex vivo restimulation of A20 LITs revealed that TIGIT+ T cells produced lower levels of effector cytokines, such as TNF-α, compared with TIGIT- T cells. In mice with established A20 lymphomas, both TIGIT and PD-1 mono-blockade led to modest delays in tumor outgrowth compared with mice treated with isotype control antibodies. Strikingly, however, combined PD-1 and TIGIT blockade resulted in complete rejection of A20 lymphomas in most mice and led to significantly prolonged survival compared to mice treated with single agent CBT (Figure C). Combination TIGIT and 4-1BB CBT was also remarkably effective in driving rejection of A20 lymphomas, and led to remarkable memory responses. Conclusions: TIGIT promotes immune tolerance in the DLBCL environment. While TIGIT monotherapy has anti-lymphoma activity, combinatorial CBT incorporating anti-TIGIT antibodies drives extremely potent rejection of established lymphomas in mice. These results provide rationale for further study of TIGIT blockade as a therapeutic strategy in r/r lymphomas, including DLBCL. Disclosures Sunseri: iTeos Therapeutics: Research Funding. Wald:iTeos Therapeutics: Employment. Preillon:iTeos Therapeutics: Employment. Smith:Portola Pharmaceuticals: Research Funding. Driessens:iTeos Therapeutics: Employment. Kline:Merck: Honoraria; Merck: Research Funding.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Gary Kwok Cheong Lee ◽  
Dorothee Bienzle ◽  
Stefan Matthias Keller ◽  
Mei-Hua Hwang ◽  
Nikos Darzentas ◽  
...  

Abstract Background Lymphocytic neoplasms with frequent reactive lymphocytes are uncommonly reported in dogs, and can pose a diagnostic challenge. Different diagnostic modalities such as cytology, flow cytometry, histopathology, immunohistochemistry, and clonality testing, are sometimes required for a diagnosis. This report illustrates the value of using a multi-modal diagnostic approach to decipher a complex lymphocytic tumor, and introduces immune repertoire sequencing as a diagnostic adjunct. Case presentation A 10-month-old Great Dane was referred for marked ascites. Cytologic analysis of abdominal fluid and hepatic aspirates revealed a mixed lymphocyte population including numerous large lymphocytes, yielding a diagnosis of lymphoma. Flow cytometrically, abdominal fluid lymphocytes were highly positive for CD4, CD5, CD18, CD45, and MHC II, consistent with T cell lymphoma. Due to a rapidly deteriorating clinical condition, the dog was euthanized. Post mortem histologic evaluation showed effacement of the liver by aggregates of B cells surrounded by T cells, suggestive of hepatic T cell-rich large B cell lymphoma. Immune repertoire sequencing confirmed the presence of clonal B cells in the liver but not the abdominal fluid, whereas reactive T cells with shared, polyclonal immune repertoires were found in both locations. Conclusions T cell-rich large B cell lymphoma is a rare neoplasm in dogs that may be challenging to diagnose and classify due to mixed lymphocyte populations. In this case, the results of histopathology, immunohistochemistry and immune repertoire sequencing were most consistent with a hepatic B cell neoplasm and reactive T cells exfoliating into the abdominal fluid. Immune repertoire sequencing was helpful in delineating neoplastic from reactive lymphocytes and characterizing repertoire overlap in both compartments. The potential pitfalls of equating atypical cytomorphology and monotypic marker expression in neoplasia are highlighted.


2016 ◽  
Vol 213 (11) ◽  
pp. 2413-2435 ◽  
Author(s):  
Yi Wang ◽  
Cindy S. Ma ◽  
Yun Ling ◽  
Aziz Bousfiha ◽  
Yildiz Camcioglu ◽  
...  

Combined immunodeficiency (CID) refers to inborn errors of human T cells that also affect B cells because of the T cell deficit or an additional B cell–intrinsic deficit. In this study, we report six patients from three unrelated families with biallelic loss-of-function mutations in RLTPR, the mouse orthologue of which is essential for CD28 signaling. The patients have cutaneous and pulmonary allergy, as well as a variety of bacterial and fungal infectious diseases, including invasive tuberculosis and mucocutaneous candidiasis. Proportions of circulating regulatory T cells and memory CD4+ T cells are reduced. Their CD4+ T cells do not respond to CD28 stimulation. Their CD4+ T cells exhibit a "Th2" cell bias ex vivo and when cultured in vitro, contrasting with the paucity of "Th1," "Th17," and T follicular helper cells. The patients also display few memory B cells and poor antibody responses. This B cell phenotype does not result solely from the T cell deficiency, as the patients’ B cells fail to activate NF-κB upon B cell receptor (BCR) stimulation. Human RLTPR deficiency is a CID affecting at least the CD28-responsive pathway in T cells and the BCR-responsive pathway in B cells.


2018 ◽  
Vol 2 (19) ◽  
pp. 2568-2580 ◽  
Author(s):  
Suparna Dutt ◽  
Michelle B. Atallah ◽  
Yoshitaka Minamida ◽  
Alexander Filatenkov ◽  
Kent P. Jensen ◽  
...  

Abstract Conventional local tumor irradiation (LTI), delivered in small daily doses over several weeks, is used clinically as a palliative, rather than curative, treatment for chemotherapy-resistant diffuse large B-cell lymphoma (DLBCL) for patients who are ineligible for hematopoietic cell transplantation. Our goal was to test the hypothesis that accelerated, but not conventional, LTI would be more curative by inducing T cell–mediated durable remissions. We irradiated subcutaneous A20 and BL3750 lymphoma tumors in mice with a clinically relevant total radiation dose of 30 Gy LTI, delivered in 10 doses of 3 Gy over 4 days (accelerated irradiation) or as 10 doses of 3 Gy over 12 days (conventional irradiation). Compared with conventional LTI, accelerated LTI resulted in more complete and durable tumor remissions. The majority of these mice were resistant to rechallenge with lymphoma cells, demonstrating the induction of memory antitumor immunity. The increased efficacy of accelerated LTI correlated with higher levels of tumor cell necrosis vs apoptosis and expression of “immunogenic cell death” markers, including calreticulin, heat shock protein 70 (Hsp70), and Hsp90. Accelerated LTI–induced remissions were not seen in immunodeficient Rag-2−/− mice, CD8+ T-cell–depleted mice, or Batf-3−/− mice lacking CD8α+ and CD103+ dendritic cells. Accelerated, but not conventional, LTI in immunocompetent hosts induced marked increases in tumor-infiltrating CD4+ and CD8+ T cells and MHCII+CD103+CD11c+ dendritic cells and corresponding reductions in exhausted PD-1+Eomes+CD8+ T cells and CD4+CD25+FOXP3+ regulatory T cells. These findings raise the possibility that accelerated LTI can provide effective immune control of human DLBCL.


2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S107-S107
Author(s):  
E Ozluk ◽  
E Wei

Abstract Introduction/Objective Growth patterns of nodular lymphocyte predominant Hogdkin lymphoma (NLPHL) has been further described by Fan et all. Pattern E is T cell/histiocyte rich large B-cell lymphoma-like and is quite rare. The treatment usually may follow large B cell lymphoma protocol instead of Hodgkin lymphoma regimen. Methods Here we report a patient with NLPHL pattern E. Patient was a 25 years-old African American man who initially presented with generalized lymphadenopathy. Results Biopsy of the axillary lymph node revealed effaced lymph node architecture by a malignant neoplasm in a diffuse and vaguely nodular pattern. In the background of a diffuse infiltrate, there were small to medium sized lymphocytes, numerous atypical large cells with irregular, basophilic nucleoli, and variable cytoplasm. The large cells focally sheeted out. Many histiocytes were also seen in the background. The large atypical cells were positive for CD20, BOB-1, OCT2, BCL-2 (focally), BCL-6, PAX5, and MUM-1, and IgD, whereas negative for BCL-1, CD10, CD15, CD30. CD2, CD3, CD4, CD5, CD7, CD8 highlighted numerous T cells with mild cytological atypia, forming rosettes around the large atypical cells. T cells were negative for ALK-1, CD1a, TdT with increased Ki-67 proliferation index around 35%. Although the surrounding T cells appear atypical in morphology, flow cytometric analysis showed predominantly reactive T-cells with no loss of T-cell associated antigens. PCR analysis showed a producible peak in a single IgH reaction. However, the fragment size of the peak observed did not meet the criteria. T-cell gene rearrangement by TCR gamma and TCR beta PCR was negative for monoclonal T-cells. BCL-1, BCL-2, and BCL-6 FISH panel were negative for gene rearrangements. Based on these findings the diagnosis was made at stage IV. Patient started treatment with R-CHOP therapy with subsequent relapse. Patient has been placed on RICE chemotherapy with partial response. Conclusion NLPHL Pattern E type should be differentiated from classical Hodgkin lymphoma, diffuse large B-cell lymphoma and peripheral T cell lymphoma because the treatment greatly differs from those with higher stage and tendency for recurrence. It is the pathologist role to lead the clinician and render a correct histopathologic diagnosis.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5486-5486
Author(s):  
Robert E. Hawkins ◽  
David E. Gilham ◽  
Fiona C. Thistlethwaite ◽  
John A. Radford ◽  
Eleanor J. Cheadle

Abstract The success of monoclonal antibodies in the treatment of certain cancers demonstrates that immune based therapies can work and are particularly effective in B cell malignancies. However, tumours can still avoid antibody mediate mechanisms of attack and there is currently no estalbished method of effectively recruiting T cells to harness their potential anti-tumour effects. We are exploring gene therapy approaches to endow T cells with antibody type specificity in order to more efficiently target and lyse tumours and thereby improve the overall immune therapy of cancer T cells grafted with a CD19 specific receptor consisting of a CD19 scFv linked to human CD3zeta (CD19z) were tested for their potency against B cell lymphoma lines in vivo. T cells were engineered using retroviral vestors to possess a CD19 specific receptor which endows the T cells with specificity for B cell lymphoma. The vector incorporates a truncated hCD34 gene as a marker to facilitate assessment of transduced cells using as clinically applicable, non-immunogenic marker gene. Mice bearing B cell lymphoma were treated with a systemic infusion of targeted T cells with or without non-myeloablative chemotherapy. Human T cells targeting CD19 cured 40% of SCID/beige mice with 6 day established metastatic tumour but only in conjunction with a single dose of cyclophosphamide. Murine T cells expressing the CD19z receptor were also effective with cure of 24hr established s.c human CD19+ tumour in SCID/beige and immunocompetent mice. Pretreatment with cyclophosphamide did not affect T cell engraftment or efficacy in immuno-compromised animals but was necessary for T cell engraftment in immuno-competent animals. These results which parallel the approach successfully used with tumour infiltrating lymhocytes in melanoma patients conclusively demonstrate that the combination of engineered T cells with “pre-conditioning” chemotherapy significantly impacts upon tumour growth in vivo and this evidence supports the development of phase I clinical trials targeting B cell lymphoma.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2623-2623 ◽  
Author(s):  
Bindu Varghese ◽  
Behnaz Taidi ◽  
Adam Widman ◽  
James Do ◽  
R. Levy

Abstract Introduction: Anti-idiotype antibodies against B cell lymphoma have shown remarkable success in causing tumor regression in the clinic. In addition to their known ability to mediate ADCC, anti-idiotype antibodies have also been shown to directly inhibit the proliferation of tumor cells by sending negative growth signals via the target idiotype. However, further studies to investigate this mechanism have been hindered by the failure of patient tumor cells to grow ex vivo. Methods and Results: In order to study this phenomenon further, we developed an antibody against the idiotype on an A20 mouse B lymphoma cell line. A radioactive thymidine incorporation assay showed decreased A20 cell proliferation in the presence of the anti-id antibody ex vivo. In vivo, when mice were treated intraperitoneally (i.p.) with 100 μg of antibody 3 hours post-tumor inoculation (1×106 A20 subcutaneously (s.c.)), tumor growth was delayed for greater than 40 days after which the tumor began to grow once again. Further analysis of these escaping tumor cells by flow cytometry showed that that the tumor cells escaped the antibody-mediated immune response by down-regulating expression of idiotype and IgG on their surfaces although the cells retained idiotype expression intracellularly. This down-regulation of surface idiotype rendered the tumor cells resistant to both ADCC and signaling-induced cell death. The addition of an immunostimulatory bacterial mimic (CpG-DNA; 100 μg × 5 intratumoral (i.t.) injections; Days 2, 3 4, 6 & 8) to antibody therapy (Day 0; 100 μg i.p.) cured large established tumors (Day 0 = 1 cm2) and prevented the occurrence of tumor escapees (p<0.0001). Antibody plus CpG combination therapy in tumor-bearing mice deficient for CD8+ T cells demonstrated the critical role of CD8+ T cells in A20 tumor eradication (p<0.005). Depletion of CD4+ T cells was found to have no significant impact on the therapy. We also found that when mice were inoculated with two tumors and treated with anti-idiotype antibody (i.p.) followed by intratumoral CpG in just one tumor (Day 0=1 cm2; anti-idiotype antibody 100 μg Day 0; 100 μg CpG Days 2, 3, 4, 6 & 8), untreated tumors regressed just as well as CpG-treated tumors indicating a systemic anti-tumor immune response was generated. Conclusion: Anti-idiotype therapy, although effective in delaying tumor growth, frequently generates antigen-loss variants. However, we found that when anti-idiotype antibodies were combined with CpG, even large established tumors were cured due to systemic CD8+ T cell-dependent tumor immunity. Rather than simply mediating ADCC against a single tumor antigen, which requires the constant infusion of antibody to hamper tumor growth, we hypothesize a cytotoxic T-cell response against many tumor antigens was also generated. Such a diverse T-cell repertoire can prevent the emergence of tumor escapees and collectively provide long-lasting tumor protection. These pre-clinical results suggest that anti-tumor antibodies combined with CpG warrant further study in patients with B cell lymphoma.


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.


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.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4840-4840
Author(s):  
Ioannis Baltadakis ◽  
Despina Mallouri ◽  
Ioannis Tsonis ◽  
Eleni Gavriilaki ◽  
Maria Bouzani ◽  
...  

Abstract Introduction: Immunotherapy with Chimeric Antigen Receptor T cells (CAR-Τ) is a promising innovative treatment for refractory B cell malignancies offering a considerable chance for long-term survival in patients (pts) with an otherwise dismal prognosis. Since January 2020, two anti-CD19 CAR T cell products have been introduced into clinical practice in Greece: a) tisagenlecleucel (Kymriah) for adults with relapsed/refractory diffuse large B-cell Lymphoma (r/r DLBCL) including transformed follicular lymphoma (TFL), as well as for children or young adults with relapsed/refractory B cell acute lymphoblastic leukemia (B-ALL), and b) axicabtagene ciloleucel (Yescarta) for adults with r/r DLBCL including TFL and primary mediastinal B-cell lymphoma (PMBCL). The aim of this study was to present the real-world experience of the initial application of CAR T cell therapy in adult pts in Greece, with special focus on early toxicity and disease outcomes. Methods: Data from all consecutive pts were collected from the two transplant centers which were initially accredited for CAR T cell therapies in adult pts: Evangelismos Hospital, Athens and George Papanicolaou Hospital, Thessaloniki. Between November 2019 and July 2021, 51 pts were referred for CAR T cell treatment. In 41 pts lymphocyte collection was performed and product manufacturing was successfully completed in 35; in 2 pts insufficient cell expansion was noted and in 4 manufacturing was terminated due to disease progression and patient death. Results: From January 2020 until July 2021, CAR T cells were infused in 27 pts; 3 pts could not receive the product due to clinical deterioration/death and 5 pts are presently being scheduled for infusion. Of the 27 treated pts, 16 received tisagenlecleucel and 11 axicabtagene ciloleucel. The median age of infused pts was 49 (18-69) years. Diagnosis was DLBCL (n=16), PMBCL (n=3), TFL (n=2), B-ALL (n=6), and the median number of previous lines of treatment was 4 (2-5). Five pts with lymphoma had undergone autologous, and 4 pts with B-ALL allogeneic stem cell transplantation. In total 18/27 pts received bridging therapy, including radiotherapy (n=5), chemoimmunotherapy (n=9), steroids (n=3), and inotuzumab ozogamicin (n=1). The median time from leukapheresis to product delivery and infusion was 35 (15-81) and 59 (35-152) days, respectively. All pts received lymphodepleting therapy before CAR T cell infusion with combination of cyclophosphamide and fludarabine. For patient monitoring, prophylactic therapy and management of toxicity, the EBMT (Yakoub-Agha I, et al. Haematologica 2020) and MD Anderson (Neelapu S, et al. Nat Rev Clin Oncol 2018) guidelines were adopted. Twenty-six pts developed neutropenia (grade II: 2, grade IV: 24) and 20 thrombocytopenia (grade I: 7, grade II: 3, grade III: 1, grade IV: 9), with a median duration of 11 (4-132) and 20 (3-150) days, respectively. Cytokine release syndrome (CRS) and neurotoxicity (ICANS) were noted in 21 (grade I: 8, grade II: 7, grade III: 6) and 5 (grade I: 3, grade III: 2) pts, respectively. Tocilizumab was administered for CRS according to guidelines, and steroids were additionally required for CRS and/or ICANS in 12 pts. In 2 pts, persistent ICANS necessitated further treatment with anakinra (n=2), siltuximab (n=1), and cyclophosphamide (n=1). Hypogammaglobulinemia was encountered in 14/27 pts. With a median follow-up of 7.3 (1-17) months, overall response rate was 48% with 12 (45%) pts being currently in complete remission (CR). No treatment related mortality was observed. Disease-free (DFS) and overall survival (OS) were 52% and 85.3% at 1-year, respectively. DFS and OS were significantly associated with baseline LDH levels (p=0.017 and 0.050, respectively) and grade II/III CRS (p=0.041 and 0.015, respectively, Figure). Conclusions: Despite the limited experience in the real-world setting, CAR T cell therapy can be administered safely and may successfully rescue patients with DLBCL or B-ALL who lack alternative treatment options. Close monitoring of patients and prompt recognition and management of side effects are mandatory for achieving the benefits of therapy. Figure 1 Figure 1. Disclosures Baltadakis: WinMedica: Other: Travel Grants; Gilead: Other: Travel Grants; Genesis Pharma: Other: Travel Grants; Abbvie: Honoraria; Novartis: Honoraria; Gilead: Honoraria; Pfizer: Honoraria, Other: Travel Grants; Astellas: Honoraria; Alexion: Honoraria; Bristol-Myers Squibb: Honoraria; Amgen: Honoraria; Baxalta Hellas: Other: Travel Grants. Gavriilaki: Pfizer Corporation: Research Funding; Gilead Corporation: Honoraria; Alexion, Omeros, Sanofi Corporation: Consultancy. Tzannou: Allovir: Current equity holder in publicly-traded company; Gileas: Honoraria. Anagnostopoulos: Abbvie: Other: clinical trials; Sanofi: Other: clinical trials ; Ocopeptides: Other: clinical trials ; GSK: Other: clinical trials; Incyte: Other: clinical trials ; Takeda: Other: clinical trials ; Amgen: Other: clinical trials ; Janssen: Other: clinical trials; novartis: Other: clinical trials; Celgene: Other: clinical trials; Roche: Other: clinical trials; Astellas: Other: clinical trials .


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