scholarly journals Genome Editing as a Vehicle to Drive Successful Chimeric Antigen Receptor T Cell Therapies to the Clinic

Author(s):  
Caitlin R Hopkins ◽  
Joseph A Fraietta

Chimeric antigen receptor (CAR) T cells have emerged as an effective therapy for patients with relapsed and refractory haematological malignancies. However, there are many challenges preventing clinical efficacy and thus broader translation of this approach. These hurdles include poor autologous T cell fitness, manufacturing issues and lack of conserved tumour-restricted antigens to target. Recent efforts have been directed toward incorporating genome editing technologies to address these challenges and develop potent CAR T cell therapies for a diverse array of haematopoietic cancers. In this review, the authors discuss gene editing strategies that have been employed to augment CAR T cell fitness, generate allogeneic ‘off-the-shelf’ CAR T cell products, and safely target elusive myeloid and T cell cancers that often lack appropriate tumour-specific antigens.

2020 ◽  
Author(s):  
L Nicolas Gonzalez Castro ◽  
Jorg Dietrich

Abstract Adoptive cell therapies (ACT) are a group of cancer immunotherapies that involve the infusion of engineered immune cells targeting specific tumor antigens, with chimeric antigen receptor (CAR) T-cells at the vanguard of this revolution in cancer therapy. Several CAR T-cell products have been approved for the treatment of leukemia and lymphoma and many more are currently undergoing evaluation in clinical trials for the treatment of other liquid and solid malignancies. Despite their remarkable effectiveness, as with other immunotherapies, CAR T-cells are frequently associated with systemic and neurologic toxicity. There has been a major effort by many institutions to develop specific protocols to guide management of treatment associated toxicities (e.g., cytokine release syndrome, CRS). However, neurotoxic effects of CAR T-cell therapies are more difficult to evaluate and treat, not easily lending themselves to an algorithmic approach to diagnosis and management. Given the steadily expanding use of CAR T-cell therapies for various malignancies, it is of critical importance for neuro-oncologists to be familiar with the clinical presentation and management principles of CAR T-cell-associated neurotoxicity. Here we present key principles for the evaluation and management of patients affected by CAR T-cell associated neurotoxicity based on the most recent evidence.


2021 ◽  
Vol 61 (1) ◽  
pp. 805-829
Author(s):  
Edward Z. Song ◽  
Michael C. Milone

Cell-based immunotherapies using T cells that are engineered to express a chimeric antigen receptor (CAR-T cells) are an effective treatment option for several B cell malignancies. Compared with most drugs, CAR-T cell products are highly complex, as each cell product is composed of a heterogeneous mixture of millions of cells. The biodistribution and kinetics of CAR-T cells, following administration, are unique given the ability of T cells to actively migrate as well as replicate within the patient. CAR-T cell therapies also have multiple mechanisms of action that contribute to both their antitumor activity and their toxicity. This review provides an overview of the unique pharmacology of CAR-T cells, with a focus on CD19-targeting and B cell maturation antigen (BCMA)-targeting CAR-T cells.


Author(s):  
Niamh Carey ◽  
Conor Hickey ◽  
Laura Mc Cullagh ◽  
Michael Barry

IntroductionIn 2018, the National Centre for Pharmacoeconomics (NCPE) was commissioned to conduct a health technology assessment (HTA) of one of the first commercially available chimeric antigen receptor (CAR) T-cell therapies, tisagenlecleucel. CAR T-cells are a major advance in personalized cancer treatment, demonstrating promising outcomes in relapsed/refractory pediatric acute lymphoblastic leukemia (pALL). However, the results are based on short-term follow up, limiting their value in predicting long-term survival and leading to uncertainty about the most appropriate survival modeling method to employ. This study aimed to address these limitations by means of expert elicitation.MethodsAn expert elicitation method, the histogram technique, was employed. A predefined discrete numerical scale was presented in Microsoft Excel® and the expert was asked to place twenty crosses on a frequency chart. These crosses represented the expert's beliefs about the distribution of particular quantities. Each cross represented five percent of the probabilistic distribution. Individual distributions were then aggregated across experts using linear pooling.ResultsA total of seventeen experts were invited to take part; eight agreed to participate and five completed the exercise. Three experts did not consider tisagenlecleucel to be a “curative” therapy because patients had a higher risk of death, compared with the age- and sex-matched general population. The aggregated distributions indicated the five-year overall survival rate to be thirty-three percent (95% CI 8.65–56.88) in patients who do not receive a subsequent stem cell transplant and twenty percent (95% CI 2.38 -52.04) in those who do.ConclusionsThe results of this study will be used to calibrate CD19 CAR T-cell therapy survival estimates presented in HTA submissions to the NCPE to ensure more robust assessments. They will also be used to inform the construction of a de novo cost-utility model for examining the cost effectiveness of CD19 CAR T-cell therapies for relapsed/refractory pALL in the Irish healthcare setting.


2019 ◽  
Vol 14 (1) ◽  
pp. 60-69
Author(s):  
Manxue Fu ◽  
Liling Tang

Background: Chimeric Antigen Receptor (CAR) T cell immunotherapy, as an innovative method for tumor immunotherapy, acquires unprecedented clinical outcomes. Genetic modification not only provides T cells with the antigen-binding function but also endows T cells with better immunological functions both in solid and hematological cancer. However, the CAR T cell therapy is not perfect because of several reasons, such as tumor immune microenvironment, and autologous limiting factors of CAR T cells. Moreover, the safety of CAR T cells should be improved.Objective:Recently many patents and publications have reported the importance of CAR T cell immunotherapy. Based on the patents about CAR T cell immunotherapy, we conclude some methods for designing the CAR which can provide information to readers.Methods:In this review, we collect recent patents and publications, summarize some specific antigens for oncotherapy from patents and enumerate some approaches to conquering immunosuppression and reinforcing the immune response of CAR T cells. We also sum up some strategies for improving the safety of CAR T cell immunotherapy.Results:CAR T cell immunotherapy as a neotype cellular immunotherapy has been proved effective in oncotherapy and authorized by FDA. Improvements in CAR designing enhance functions of CAR T cells.Conclusion:This review, summarizing antigens and approaches to overcome defects of CAR T cell immunotherapy from patents and publications, might contribute to a broad readership.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chunyi Shen ◽  
Zhen Zhang ◽  
Yi Zhang

Immunotherapy, especially based on chimeric antigen receptor (CAR) T cells, has achieved prominent success in the treatment of hematological malignancies. However, approximately 30-50% of patients will have disease relapse following remission after receiving CD19-targeting CAR-T cells, with failure of maintaining a long-term effect. Mechanisms underlying CAR-T therapy inefficiency consist of loss or modulation of target antigen and CAR-T cell poor persistence which mostly results from T cell exhaustion. The unique features and restoration strategies of exhausted T cells (Tex) have been well described in solid tumors. However, the overview associated with CAR-T cell exhaustion is relatively rare in hematological malignancies. In this review, we summarize the characteristics, cellular, and molecular mechanisms of Tex cells as well as approaches to reverse CAR-T cell exhaustion in hematological malignancies, providing novel strategies for immunotherapies.


2020 ◽  
Vol 94 (10) ◽  
Author(s):  
Matthew T. Ollerton ◽  
Edward A. Berger ◽  
Elizabeth Connick ◽  
Gregory F. Burton

ABSTRACT The major obstacle to a cure for HIV infection is the persistence of replication-competent viral reservoirs during antiretroviral therapy. HIV-specific chimeric antigen receptor (CAR) T cells have been developed to target latently infected CD4+ T cells that express virus either spontaneously or after intentional latency reversal. Whether HIV-specific CAR-T cells can recognize and eliminate the follicular dendritic cell (FDC) reservoir of HIV-bound immune complexes (ICs) is unknown. We created HIV-specific CAR-T cells using human peripheral blood mononuclear cells (PBMCs) and a CAR construct that enables the expression of CD4 (domains 1 and 2) and the carbohydrate recognition domain of mannose binding lectin (MBL) to target native HIV Env (CD4-MBL CAR). We assessed CAR-T cell cytotoxicity using a carboxyfluorescein succinimidyl ester (CFSE) release assay and evaluated CAR-T cell activation through interferon gamma (IFN-γ) production and CD107a membrane accumulation by flow cytometry. CD4-MBL CAR-T cells displayed potent lytic and functional responses to Env-expressing cell lines and HIV-infected CD4+ T cells but were ineffective at targeting FDC bearing HIV-ICs. CD4-MBL CAR-T cells were unresponsive to cell-free HIV or concentrated, immobilized HIV-ICs in cell-free experiments. Blocking intercellular adhesion molecule-1 (ICAM-1) inhibited the cytolytic response of CD4-MBL CAR-T cells to Env-expressing cell lines and HIV-infected CD4+ T cells, suggesting that factors such as adhesion molecules are necessary for the stabilization of the CAR-Env interaction to elicit a cytotoxic response. Thus, CD4-MBL CAR-T cells are unable to eliminate the FDC-associated HIV reservoir, and alternative strategies to eradicate this reservoir must be sought. IMPORTANCE Efforts to cure HIV infection have focused primarily on the elimination of latently infected CD4+ T cells. Few studies have addressed the unique reservoir of infectious HIV that exists on follicular dendritic cells (FDCs), persists in vivo during antiretroviral therapy, and likely contributes to viral rebound upon cessation of antiretroviral therapy. We assessed the efficacy of a novel HIV-specific chimeric antigen receptor (CAR) T cell to target both HIV-infected CD4+ T cells and the FDC reservoir in vitro. Although CAR-T cells eliminated CD4+ T cells that express HIV, they did not respond to or eliminate FDC bound to HIV. These findings reveal a fundamental limitation to CAR-T cell therapy to eradicate HIV.


2017 ◽  
Vol 13 (01) ◽  
pp. 28 ◽  
Author(s):  
Andrew Fesnak ◽  
Una O’Doherty ◽  
◽  

Adoptive transfer of chimeric antigen receptor (CAR) T cells is a powerful targeted immunotherapeutic technique. CAR T cells are manufactured by harvesting mononuclear cells, typically via leukapheresis from a patient’s blood, then activating, modifying the T cells to express a transgene encoding a tumour-specific CAR, and infusing the CAR T cells into the patient. Gene transfer is achieved through the use of retroviral or lentiviral vectors, although non-viral delivery systems are being investigated. This article discusses the challenges associated with each stage of this process. Despite the need for a consistent end product, there is inherent variability in cellular material obtained from critically ill patients who have been exposed to cytotoxic therapy. It is important to carefully select target antigens to maximise effect and minimise toxicity. Various types of CAR T cell toxicity have been documented: this includes “on target, on tumour”, “on target, off tumour” and “off target” toxicity. A growing body of clinical evidence supports the efficacy and safety of CAR T cell therapy; CAR T cells targeting CD19 in B cell leukemias are the best-studied therapy to date. However, providing personalised therapy on a large scale remains challenging; a future aim is to produce a universal “off the shelf” CAR T cell.


2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Gregory J. Kimmel ◽  
Frederick L. Locke ◽  
Philipp M. Altrock

Chimeric antigen receptor (CAR) T cell therapy is a remarkably effective immunotherapy that relies on in vivo expansion of engineered CAR T cells, after lymphodepletion (LD) by chemotherapy. The quantitative laws underlying this expansion and subsequent tumour eradication remain unknown. We develop a mathematical model of T cell–tumour cell interactions and demonstrate that expansion can be explained by immune reconstitution dynamics after LD and competition among T cells. CAR T cells rapidly grow and engage tumour cells but experience an emerging growth rate disadvantage compared to normal T cells. Since tumour eradication is deterministically unstable in our model, we define cure as a stochastic event, which, even when likely, can occur at variable times. However, we show that variability in timing is largely determined by patient variability. While cure events impacted by these fluctuations occur early and are narrowly distributed, progression events occur late and are more widely distributed in time. We parameterized our model using population-level CAR T cell and tumour data over time and compare our predictions with progression-free survival rates. We find that therapy could be improved by optimizing the tumour-killing rate and the CAR T cells' ability to adapt, as quantified by their carrying capacity. Our tumour extinction model can be leveraged to examine why therapy works in some patients but not others, and to better understand the interplay of deterministic and stochastic effects on outcomes. For example, our model implies that LD before a second CAR T injection is necessary.


2021 ◽  
Vol 3 (3) ◽  
pp. 46-47
Author(s):  
Yuanzheng Liang ◽  

Chimeric antigen receptor (CAR) T-cell therapy has drawn the most attention ever in the treatment of hematologic malignancies due to its impressive efficacy in heavily pretreated patients. However, the use of CAR T-cell therapy has just started in the field of solid tumor. Till now, four CAR T-cell therapies have been approved in the world, and an increasing number of patients will receive this expensive treatment. Thus, we will briefly talk about the advances and challenges in the adventure of CAR T-cell therapy


Author(s):  
Bill X. Wu ◽  
No-Joon Song ◽  
Brian P. Riesenberg ◽  
Zihai Li

Abstract The use of chimeric antigen receptor (CAR) T cell technology as a therapeutic strategy for the treatment blood-born human cancers has delivered outstanding clinical efficacy. However, this treatment modality can also be associated with serious adverse events in the form of cytokine release syndrome. While several avenues are being pursued to limit the off-target effects, it is critically important that any intervention strategy has minimal consequences on long term efficacy. A recent study published in Science Translational Medicine by Dr. Hudecek’s group proved that dasatinib, a tyrosine kinase inhibitor, can serve as an on/off switch for CD19-CAR-T cells in preclinical models by limiting toxicities while maintaining therapeutic efficacy. In this editorial, we discuss the recent strategies for generating safer CAR-T cells, and also important questions surrounding the use of dasatinib for emergency intervention of CAR-T cell mediated cytokine release syndrome.


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