scholarly journals Killing Mechanisms of Chimeric Antigen Receptor (CAR) T Cells

2019 ◽  
Vol 20 (6) ◽  
pp. 1283 ◽  
Author(s):  
Mohamed-Reda Benmebarek ◽  
Clara Karches ◽  
Bruno Cadilha ◽  
Stefanie Lesch ◽  
Stefan Endres ◽  
...  

Effective adoptive T cell therapy (ACT) comprises the killing of cancer cells through the therapeutic use of transferred T cells. One of the main ACT approaches is chimeric antigen receptor (CAR) T cell therapy. CAR T cells mediate MHC-unrestricted tumor cell killing by enabling T cells to bind target cell surface antigens through a single-chain variable fragment (scFv) recognition domain. Upon engagement, CAR T cells form a non-classical immune synapse (IS), required for their effector function. These cells then mediate their anti-tumoral effects through the perforin and granzyme axis, the Fas and Fas ligand axis, as well as the release of cytokines to sensitize the tumor stroma. Their persistence in the host and functional outputs are tightly dependent on the receptor’s individual components—scFv, spacer domain, and costimulatory domains—and how said component functions converge to augment CAR T cell performance. In this review, we bring forth the successes and limitations of CAR T cell therapy. We delve further into the current understanding of how CAR T cells are designed to function, survive, and ultimately mediate their anti-tumoral effects.

Blood ◽  
2016 ◽  
Vol 127 (26) ◽  
pp. 3321-3330 ◽  
Author(s):  
Jennifer N. Brudno ◽  
James N. Kochenderfer

Abstract Chimeric antigen receptor (CAR) T cells can produce durable remissions in hematologic malignancies that are not responsive to standard therapies. Yet the use of CAR T cells is limited by potentially severe toxicities. Early case reports of unexpected organ damage and deaths following CAR T-cell therapy first highlighted the possible dangers of this new treatment. CAR T cells can potentially damage normal tissues by specifically targeting a tumor-associated antigen that is also expressed on those tissues. Cytokine release syndrome (CRS), a systemic inflammatory response caused by cytokines released by infused CAR T cells can lead to widespread reversible organ dysfunction. CRS is the most common type of toxicity caused by CAR T cells. Neurologic toxicity due to CAR T cells might in some cases have a different pathophysiology than CRS and requires different management. Aggressive supportive care is necessary for all patients experiencing CAR T-cell toxicities, with early intervention for hypotension and treatment of concurrent infections being essential. Interleukin-6 receptor blockade with tocilizumab remains the mainstay pharmacologic therapy for CRS, though indications for administration vary among centers. Corticosteroids should be reserved for neurologic toxicities and CRS not responsive to tocilizumab. Pharmacologic management is complicated by the risk of immunosuppressive therapy abrogating the antimalignancy activity of the CAR T cells. This review describes the toxicities caused by CAR T cells and reviews the published approaches used to manage toxicities. We present guidelines for treating patients experiencing CRS and other adverse events following CAR T-cell therapy.


Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1229
Author(s):  
Ali Hosseini Rad S. M. ◽  
Joshua Colin Halpin ◽  
Mojtaba Mollaei ◽  
Samuel W. J. Smith Bell ◽  
Nattiya Hirankarn ◽  
...  

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized adoptive cell therapy with impressive therapeutic outcomes of >80% complete remission (CR) rates in some haematological malignancies. Despite this, CAR T cell therapy for the treatment of solid tumours has invariably been unsuccessful in the clinic. Immunosuppressive factors and metabolic stresses in the tumour microenvironment (TME) result in the dysfunction and exhaustion of CAR T cells. A growing body of evidence demonstrates the importance of the mitochondrial and metabolic state of CAR T cells prior to infusion into patients. The different T cell subtypes utilise distinct metabolic pathways to fulfil their energy demands associated with their function. The reprogramming of CAR T cell metabolism is a viable approach to manufacture CAR T cells with superior antitumour functions and increased longevity, whilst also facilitating their adaptation to the nutrient restricted TME. This review discusses the mitochondrial and metabolic state of T cells, and describes the potential of the latest metabolic interventions to maximise CAR T cell efficacy for solid tumours.


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.


Author(s):  
Bikash Pal ◽  
Bornika Chattaraj ◽  
Purnima Agrawal

Chimeric antigen receptor T-cells or CAR T-cell therapy is a newly discovered method that has shown great promise for the global patient population to cure cancer. Chimeric antigen receptor T-cells are generally prepared by removing T-cells from the patients’ blood and modifying them using genetic engineering, to express a Chimeric Antigen Receptor on their surface. The studies done so far have shown its major effectiveness against Beta-cell malignancy, ovarian carcinoma, and lymphoblastic leukemia. The therapy can cause Cytokine Release Syndrome, neurotoxicity syndrome, tumor lysis, etc. as its major adverse event. But recent improvements in the therapy has proved that these adverse events can be effectively minimized to a great extent. The future of CAR T-cell therapy is very promising and is expected to fulfil all global regulatory requirements as well as overcome any manufacturing and toxicological obstacles and become available for a large number of populations. This review is based on the overall prospects of CAR T-cell therapy, the major toxicity related problems, and the prospect of this therapy.


2021 ◽  
Vol 16 ◽  
Author(s):  
Vikas Maharshi ◽  
Diksha Diksha ◽  
Pooja Gupta

Background: Serious adverse reactions have been reported with the use of chimeric antigen receptor (CAR) T-cell therapy in clinical setting despite the success of these products in pre-clinical stages of development. Objective: We evaluated the quality of available pre-clinical safety data of CAR T-cell therapy products. Methods: A 21 items safety-checklist was designed specifically for CAR T-cell. Literature was searched using search/MeSH terms in PubMed (October 2019 – February 2020). Studies were screened from title and abstract. Original pre-clinical researches related to CAR T-cell anti-cancer therapy were included. Results: Of the search results, 152 studies (3 in vivo, 39 in vitro, and 110 combined) were included. Only 7.9% studies were specifically designed to evaluate/ improve product safety. Eleven studies included target antigen(s) and no study included co-stimulatory molecule(s) expressed exclusively by tumor tissue and/or CAR T-cells. One study used CRISPR-Cas9 for CAR gene insertion. The use of switch-off mechanism and purity assessment of CAR T-cell products were reported in 13.2% and 8.6% studies respectively. Of the 149 studies with in vivo component, immuno-competent animal models were used in 24.8%. Measurement of blood pressure, temperature, body weight and serum cytokines were reported in 0, 2.7, 29.2 and 27.4% studies respectively. The tissue distribution and CAR T-cells persistence were reported in 26.5% studies. Conclusion: Majority of the checklist parameters were not reported in the pre-clinical publications to be adequately predictive of the safety of CAR T-cells in a clinical setting.


2020 ◽  
Vol 6 (21) ◽  
pp. eaaz3223 ◽  
Author(s):  
S. E. Lindner ◽  
S. M. Johnson ◽  
C. E. Brown ◽  
L. D. Wang

Chimeric antigen receptor (CAR) T cell therapy has transformed the care of refractory B cell malignancies and holds tremendous promise for many aggressive tumors. Despite overwhelming scientific, clinical, and public interest in this rapidly expanding field, fundamental inquiries into CAR T cell mechanistic functioning are still in their infancy. Because CAR T cells are manufactured from donor T lymphocytes, and because CARs incorporate well-characterized T cell signaling components, it has largely been assumed that CARs signal analogously to canonical T cell receptors (TCRs). However, recent studies demonstrate that many aspects of CAR signaling are unique, distinct from endogenous TCR signaling, and potentially even distinct among various CAR constructs. Thus, rigorous and comprehensive proteomic investigations are required for rational engineering of improved CARs. Here, we review what is known about proximal CAR signaling in T cells, compare it to conventional TCR signaling, and outline unmet challenges to improving CAR T cell therapy.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1450
Author(s):  
Tahereh Soltantoyeh ◽  
Behnia Akbari ◽  
Amirali Karimi ◽  
Ghanbar Mahmoodi Chalbatani ◽  
Navid Ghahri-Saremi ◽  
...  

Metastatic melanoma is the most aggressive and difficult to treat type of skin cancer, with a survival rate of less than 10%. Metastatic melanoma has conventionally been considered very difficult to treat; however, recent progress in understanding the cellular and molecular mechanisms involved in the tumorigenesis, metastasis and immune escape have led to the introduction of new therapies. These include targeted molecular therapy and novel immune-based approaches such as immune checkpoint blockade (ICB), tumor-infiltrating lymphocytes (TILs), and genetically engineered T-lymphocytes such as chimeric antigen receptor (CAR) T cells. Among these, CAR T cell therapy has recently made promising strides towards the treatment of advanced hematological and solid cancers. Although CAR T cell therapy might offer new hope for melanoma patients, it is not without its shortcomings, which include off-target toxicity, and the emergence of resistance to therapy (e.g., due to antigen loss), leading to eventual relapse. The present review will not only describe the basic steps of melanoma metastasis, but also discuss how CAR T cells could treat metastatic melanoma. We will outline specific strategies including combination approaches that could be used to overcome some limitations of CAR T cell therapy for metastatic melanoma.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A238-A238
Author(s):  
Yukiko Yamaguchi ◽  
Jackson Gibson ◽  
Kevin Ou ◽  
Saul Priceman

BackgroundThe immune suppressive tumor microenvironment (TME) that inhibits T cell infiltration, survival, and anti-tumor activity has posed a major challenge for developing effective immunotherapies for solid tumors. Chimeric antigen receptor T cell therapy has shown unprecedented clinical response in treating patients with hematological malignancies, and intense investigation is underway to achieve similar responses with solid tumors. Immunologically cold tumors, including prostate cancers, are often infiltrated with abundant macrophages, and infiltration of M2 macrophages correlates with metastasis and poor prognosis.MethodsTo model this in vitro, we utilized a novel co-culture system with tumor cells, prostate stem cell antigen (PSCA)-directed CAR T cells, and polarized macrophages. To investigate the TME in vivo, we took advantage of ”humanized” MISTRG mice, which are immunocompromised mice with knocked-in human genes that support human hematopoiesis and efficient tumor-infiltration of myeloid cell populations. Humanized MISTRG mice were intratibially engrafted with LAPC9 tumor cells to model bone metastatic disease.ResultsWe observed significant hampering of PSCA-CAR T cell activity in vitro with the presence of M2 macrophages, but not M1 macrophages, coinciding with a robust induction of PD-L1 in both tumor cells and macrophages. We also observed PD-L1 expression in tumor-associated macrophages infiltrating tumors following PSCA-CAR T cell therapy in the humanized mice. Anti-PD-L1 monoclonal antibodies in combination with CAR-T cell therapy altered phenotype and survival of M2 macrophages, resulting in improved anti-tumor activity of PSCA-CAR T cells in the presence of M2 macrophages.ConclusionsRecently, immune checkpoint (IC) blockade (ICB) has been utilized in combination with chimeric antigen receptor (CAR) T cell therapy, with the notion that induction of immune responses with CAR T cells may instigate checkpoint pathways in immunologically cold tumors that would otherwise not respond to ICB. This study gives insights to a mechanism by which CAR T cells and ICB work in synergy to modulate immune landscape of immunologically cold tumors, and our ongoing studies will continue to elucidate the TME-mediated immunosuppression of CAR T cell therapy.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4834-4834
Author(s):  
Jing Huang ◽  
Zhi Liu ◽  
Ruiming Ou ◽  
Liling Zheng ◽  
Yangmin Zhu ◽  
...  

Abstract Objective To evaluate the efficacy and safety of the CD19-targeted chimeric antigen receptor T-cell(CD19-CAR-T) therapy for relapsed/refractory B-cell acute lymphoblast leukemia(B-ALL). Methods The efficacy and safety of CD19-CAR-T cells(4-1BB costimulatory domain) in treatment of 34 patients with relapsed/refractory B-ALL from March 2015 to December 2019 in the Department of Hematology of Guangdong Second Province Hospital were collected analyzed retrospectively. There were 18 cases (52.9%) with high-risk cytogenetic or molecular markers, 14 cases (41.2%) with tumor load was ≥50% before transfusion, 24 cases (70.6%) with ECOG score ≥2. The number of chemotherapy courses received before transfusion was 2-15, the median number of chemotherapy courses was 5. There were 32 autogenous CAR-T cells and 2 donor-derived CAR-T cells, 11 of them received allogeneic hematopoietic stem cell transplantation (allo-HSCT) before transfusion. All were mouse CAR-T cells. Fludarabine + Cyclophosphamide (FC) regimen was used for pretreatment before transfusion, and the number of CAR-T cells was 1 ~ 13.4×10 6/kg. Results All 34 patients received CD19-targeted CAR-T cell therapy. 22 patients obtained MRD- after 1 month, CR rate was 64.7%. 20 patients maintained MRD- after 2 months, and the CR rate was 58.8%. 13 patients still maintained MRD- after 3 months, with a CR rate of 38.2%. 4 patients with recurrence presented CD19 negative recurrence. 10 patients underwent Allo-HSCT after CR acquisition, 6 of them maintained a continuous CR state, and 4 patients died after recurrence. Cytokines release syndrome (CRS) was observed in 31 patients (91.2%). Among them, there were 20 patients (64.5%) with grade 1 ~ 2, 8 patients (25.8%) with grade 3 ~ 4, and 3 patients (9.7%) with grade 5. The cytokines levels of IL-6 and IFN-γ were mainly increased in 20 (64.5%) and 18 (58.1%) patients, respectively. Common clinical adverse reactions are: fever with 32 cases (94.1%), pancytopenia with 28 cases (82.4%), chills with 17 cases (50.0%), fatigue with 26 cases (76.5%), hypotension with 27 cases (79.4%), tachycardia with 24 cases (70.6%), hypofibrinogenemia with 20 cases (58.8%), hypoproglobinemia with 27 cases (79.4%), neurotoxicity with 15 cases (44.1%), nausea with 16 cases (47.1%), vomiting with 14 cases (41.2%), hypoalbuminemia with 25 cases (73.5%), transaminase eleations with 16 cases (47.1%), electrolyte metabolic disorders with 27 cases (79.4%) , hypoxemiawith 15 cases (44.1%). Conclusion CAR-T cells therapy is a novel method for the treatment of refractory/recurrent B-ALL with CD19 antigen positive, which can make patients achieved complete remission in a short time, even achieved MRD negative, and most of the CRS appeared in the process of treatment can be controlled by treatment, but the recurrence rate is higher after 3 months later, and can appear CD19 negative relapse. Allo-HSCT as soon as possible after obtaining CR can enable some patients to obtain sustained CR.Therefore, more clinical studies are needed to explore the clinical application of CAR-T cell therapy. Currently, it is believed that bridging with allo-HSCT may be a solution to achieve sustained CR. 【Key words】Chimeric antigen receptor T-cell; Relapsed/refractory acute lymphoblast leukemia; Efficacy; Safety; Cytokine release syndrome Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2021 ◽  
Author(s):  
Kitsada Wudhikarn ◽  
Jessica R Flynn ◽  
Isabelle Rivière ◽  
Mithat Gonen ◽  
Xiuyan Wang ◽  
...  

CD19-targeted chimeric antigen receptor (CAR) T cell therapy has become a breakthrough treatment for patients with relapsed/refractory B acute lymphoblastic leukemia (B-ALL). However, despite the high initial response rate, the majority of adult patients with B-ALL progress after CD19 CAR T therapy. Data on the natural history, management, and outcome of adult B-ALL progressing after CD19 CAR T cells have not been described in detail. Herein, we report comprehensive data of 38 adult B-ALL patients who progressed after CD19 CAR T therapy at our institution. The median time to progression after CAR T therapy was 5.5 months. Median survival after post-CAR T progression was 7.4 months. A high disease burden at the time of CAR T cell infusion was significantly associated with risk of post-CAR T progression. Thirty patients (79%) received salvage treatment for post-CAR T disease progression and 13 patients (43%) achieved complete remission (CR), but remission duration was short. Notably, 7 of 12 patients (58.3%) achieved CR after blinatumomab and/or inotuzumab administered after post-CAR T failure. Multivariate analysis demonstrated longer remission duration from CAR T cells was associated with superior survival after progression following CAR T therapy. In conclusion, overall prognosis of adult B-ALL patients progressing after CD19 CAR T cells was poor though a subset of patients achieved sustained remissions to salvage treatments including blinatumomab, inotuzumab and re-infusion of CAR T cells. Novel therapeutic strategies are needed to reduce risk of progression after CAR T therapy and improve outcomes of these patients.


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