Efficacy and safety of adoptive immunotherapy using anti-CD19 chimeric antigen receptor transduced T-cells: a systematic review of phase I clinical trials

CAR T cell therapies in gastrointestinal cancers: current clinical trials and strategies to overcome challenges

Despite multimodal treatment options, most gastrointestinal cancers are still associated with high mortality rates and poor responsiveness to immunotherapy. The unprecedented efficacy of chimeric antigen receptor (CAR)-engineered T cells in the treatment of haematological malignancies raised interest in translating CAR T cell therapies to the treatment of gastrointestinal cancers. Treatment of solid cancers with canonical CAR T cells faces substantial challenges, including the dense architecture of the tumour tissue, the tolerogenic environment with low tumour-intrinsic immunogenicity, the rareness of targetable tumour-selective antigens, the antigenic heterogeneity of cancer cells, and the profound metabolic and immune cell disbalances. This Review provides an overview of CAR T cell trials in the treatment of gastrointestinal cancers, discussing considerations relating to safety, efficacy, potential reasons for failure and options for improving CAR T cells for the future. In addition, lessons regarding how to improve efficacy are drawn from CAR T cells armed with adjuvants that sustain their activation within the hostile environment and activate resident immune cells. As the field is rapidly evolving, current treatment modalities and editing CAR T cell functionalities are being refined towards a potentially more successful CAR T cell therapy for gastrointestinal cancers.

Autologous HER2-specific CAR T cells after lymphodepletion for advanced sarcoma: a phase 1 trial

In this prospective, interventional phase 1 study for individuals with advanced sarcoma, we infused autologous HER2-specific chimeric antigen receptor T cells (HER2 CAR T cells) after lymphodepletion with fludarabine (Flu) ± cyclophosphamide (Cy): 1 × 108 T cells per m2 after Flu (cohort A) or Flu/Cy (cohort B) and 1 × 108 CAR+ T cells per m2 after Flu/Cy (cohort C). The primary outcome was assessment of safety of one dose of HER2 CAR T cells after lymphodepletion. Determination of antitumor responses was the secondary outcome. Thirteen individuals were treated in 14 enrollments, and seven received multiple infusions. HER2 CAR T cells expanded after 19 of 21 infusions. Nine of 12 individuals in cohorts A and B developed grade 1-2 cytokine release syndrome. Two individuals in cohort C experienced dose-limiting toxicity with grade 3-4 cytokine release syndrome. Antitumor activity was observed with clinical benefit in 50% of individuals treated. The tumor samples analyzed showed spatial heterogeneity of immune cells and clustering by sarcoma type and by treatment response. Our results affirm HER2 as a CAR T cell target and demonstrate the safety of this therapeutic approach in sarcoma. ClinicalTrials.gov registration: NCT00902044 .

Simulating the Dynamic Intra-Tumor Heterogeneity and Therapeutic Responses

A tumor is a complex tissue comprised of heterogeneous cell subpopulations which exhibit substantial diversity at morphological, genetic and epigenetic levels. Under the selective pressure of cancer therapies, a minor treatment-resistant subpopulation could survive and repopulate. Therefore, the intra-tumor heterogeneity is recognized as a major obstacle to effective treatment. In this paper, we propose a stochastic clonal expansion model to simulate the dynamic evolution of tumor subpopulations and the therapeutic effect at different times during tumor progression. The model is incorporated in the CES webserver, for the convenience of simulation according to initial user input. Based on this model, we investigate the influence of various factors on tumor progression and treatment consequences and present conclusions drawn from observations, highlighting the importance of treatment timing. The model provides an intuitive illustration to deepen the understanding of temporal intra-tumor heterogeneity dynamics and treatment responses, thus helping the improvement of personalized diagnostic and therapeutic strategies.

Conditional control of chimeric antigen receptor T-cell activity through a destabilizing domain switch and its chemical ligand

BACKGROUND AIMS

Despite the impressive efficacy of chimeric antigen receptor (CAR) T-cell therapy, adverse effects, including cytokine release syndrome and neurotoxicity, impede its therapeutic application, thus making the modulation of CAR T-cell activity a priority. The destabilizing domain mutated from Escherichia coli dihydrofolate reductase (DHFR) is inherently unstable and degraded by proteasomes unless it is stabilized by its chemical ligand trimethoprim (TMP), a Food and Drug Administration-approved drug. Here the authors reveal a strategy to modulate CAR T-cell activity at the protein level by employing DHFR and TMP as a chemical switch system.

METHODS

First, the system was demonstrated to work in human primary T cells. To introduce the system to CAR T cells, DHFR was genetically fused to the carboxyl terminal of a third-generation CAR molecule targeting CD19 (CD19-CAR), constructing the CD19-CAR-DHFR fusion.

RESULTS

The CD19-CAR-DHFR molecule level was shown to be modulated by TMP. Importantly, the incorporation of DHFR had no impact on the recognition specificity and normal function of the CAR molecule. Little adverse effect on cell proliferation and apoptosis was detected. It was proved that TMP could regulate cytokine secretion and the in vitro cytotoxicity of CD19-CAR-DHFR T cells. Furthermore, the in vivo anti-tumor efficacy was demonstrated to be controllable through the manipulation of TMP administration. The approach to control CD19-CAR also succeeded in 19-BBZ(71), another CD19-targeting CAR with a different structure.

CONCLUSIONS

The proposed approach based on DHFR and TMP provides a facile strategy to bring CAR T-cell therapy under conditional user control, and the strategy may have the potential to be transplantable.

Acute kidney injury in cancer patients

OBJECTIVE

We want to know the causes of AKI in oncology patients, including disease-related complications and the nephrotoxicity of chemotherapy drugs, in order to provide more useful clinical information.

METHODS

In this review, an electronic search of the English language literature was performed in the database PubMed, with the results enriched by manual searches and citation mining, factors investigated in the selected articles included acute kidney injury, oncology, chemotherapy, anticancer drug, antitumor drug.

RESULTS

According to the searched articles, we summarized the causes (including pre-renal, intrinsic renal, and post-renal lesion) of AKI in cancer patients and the corresponding management measures. Among the pre-renal factors we mainly described hypercalcemia, hematopoietic cell transplantation, post-renal factors we mainly described hemorrhagic cystitis, and intrinsic renal factors we mainly described thrombotic microangiopathy, chemotherapeutics, tumor lysis syndrome, cast nephropathy, in which the emphasis was on chemotherapy drug associated AKI and its treatment.

CONCLUSIONS

AKI is not uncommon in cancer patients, and has diverse causes and negative outcomes. Both nephrologists and oncologists need to be aware of the unique reasons of AKI in this population and its optimal management.

Developing and Monitoring a Standard-of-Care Chimeric Antigen Receptor (CAR) T Cell Clinical Quality and Regulatory Program

As the world of cellular therapy expands to include immune effector cell (IEC) products such as commercial chimeric antigen receptor (CAR) T cells, quality management (QM) professionals are faced with creating either new IEC stand-alone programs or expand existing hematopoietic cell transplantation (HCT) programs to promote patient safety and be aligned with quality, regulatory, and accreditation requirements. The team professionals at City of Hope (COH) recently expanded the quality HCT program to include IEC products and, in doing so, implemented new regulatory infrastructure while maintaining high quality patient care. At COH, we developed the quality structure of our cellular therapy program through collaborations between quality, regulatory, and CAR T patient care committees, which included physicians and nurse coordinators. To ensure the quality of our program, we monitor data collection and reporting, perform quarterly proactive audits of, for example, outcome analysis, and measure selected end-points for benchmarking purposes. QM professionals play a critical role in the monitoring and evaluation processes and provide guidance on how to implement accreditation requirements and what impact the requirements may have on care management. Here we describe the process by which COH expanded our HCT QM program to include IEC therapy. We share examples of how we developed our overall program structure and other key items such as how we addressed patient care management and accreditation to apprise other programs that wish to create and/or expand existing programs.

Survival outcomes and efficacy of autologous CD19 chimeric antigen receptor-T cell therapy in the patient with diagnosed hematological malignancies: a systematic review and meta-analysis

Purpose: Chimeric Antigen Receptor T(CAR-T) cell therapy is an immunotherapy approach used in treating cancer which has seen rapid development over the decades. It becomes the preferred treatment choice after patients have failed conventional chemotherapy.

Methods: We conducted a meta-analysis in 320 patients from 14 studies to estimate the survival outcome, response rate and toxicity of autologous CD19 CAR-T cell therapy and predict other factors associated with a better prognosis.

Results: The overall response rate was 71.88% (95% CI: 61.34–80.46%, p<0.01) and CRS toxicity was 60.15% (95% CI: 42.87–75.22%, p<0.01). Patients who received lymphodepletion was associated with a better response rate (77%, 95%CI: 67–83%; p-value =0.001) in comparison to the other patients who did not (66%, 95%CI: 41–83%).

Conclusion: Lymphodepletion regimen may play a crucial role in predicting the prognosis of patients with hematological malignancies. Lymphodepletion patients had better progression-free survival than those who did not.

Optimization of manufacturing conditions for chimeric antigen receptor T cells to favor cells with a central memory phenotype

BACKGROUND

Chimeric antigen receptor (CAR)-T cells are genetically engineered to recognize tumor-associated antigens and have potent cytolytic activity against tumors. Adoptive therapy with CAR-T cells has been highly successful in B-cell leukemia and lymphoma. However, in solid tumor settings, CAR-T cells face a particularly hostile tumor microenvironment where multiple immune suppressive factors serve to thwart the anti-cancer immune response. Clinical trials of solid tumor antigen-targeted CAR-T cells have shown limited efficacy, and issues for current CAR-T cell therapies include failures of expansion and persistence, tumor entry, deletion and functional exhaustion.

METHODS

We compared our standard protocol for CAR-T cell manufacturing, currently used to generate CAR-T cells for a phase 1 clinical trial, with two alternative approaches for T-cell activation and expansion. The resulting cultures were analyzed using multicolor flow cytometry, cytokine bead array and xCELLigence cytotoxicity assays.

RESULTS

We have found that by changing the method of activation we can promote generation of CAR-T cells with enhanced CD62L and CCR7 expression, increased interleukin (IL)-2 production and retention of cytolytic activity, albeit with slower kinetics.

DISCUSSION

We propose that these phenotypic characteristics are consistent with a central memory phenotype that will better enable CAR-T cell survival and persistence after activation in vivo, and we aim to test this in a continuation of our current phase 1 clinical trial of CAR-T cells in patients with advanced melanoma.

The efficacy and safety of anti-CD19/CD20 chimeric antigen receptor- T cells immunotherapy in relapsed or refractory B-cell malignancies:a meta-analysis

BACKGROUND

Chimeric antigen receptor T (CAR T) cells immunotherapy is rapidly developed in treating cancers, especially relapsed or refractory B-cell malignancies.

METHODS

To assess the efficacy and safety of CAR T therapy, we analyzed clinical trials from PUBMED and EMBASE.

RESULTS

Results showed that the pooled response rate, 6-months and 1-year progression-free survival (PFS) rate were 67%, 65.62% and 44.18%, respectively. We observed that received lymphodepletion (72% vs 44%, P = 0.0405) and high peak serum IL-2 level (85% vs 31%, P = 0.04) were positively associated with patients' response to CAR T cells. Similarly, costimulatory domains (CD28 vs CD137) in second generation CAR T was positively associated with PFS (52.69% vs 33.39%, P = 0.0489). The pooled risks of all grade adverse effects (AEs) and grade ≥ 3 AEs were 71% and 43%. Most common grade ≥ 3 AEs were fatigue (18%), night sweats (14%), hypotension (12%), injection site reaction (12%), leukopenia (10%), anemia (9%).

CONCLUSIONS

In conclusion, CAR T therapy has promising outcomes with tolerable AEs in relapsed or refractory B-cell malignancies. Further modifications of CAR structure and optimal therapy strategy in continued clinical trials are needed to obtain significant improvements.

Multiparameter comparative analysis reveals differential impacts of various cytokines on CART cell phenotype and function ex vivo and in vivo

Exogenous cytokines are widely applied to enhance the anti-tumor ability of immune cells. However, systematic comparative studies of their effects on chimeric antigen receptor (CAR)-engineered T (CART) cells are lacking. In this study, CART cells targeting folate receptor-alpha were generated and expanded ex vivo in the presence of different cytokines (IL-2, IL-7, IL-15, IL-18, and IL-21), and their expansion, phenotype and cytotoxic capacity were evaluated, in vitro and in vivo. Moreover, the effect of the administration of these cytokines along with CART cells in vivo was also studied. IL-2, IL-7, and IL-15 favored the ex vivo expansion of CART cells compared to other cytokines or no cytokine treatment. IL-7 induced the highest proportion of memory stem cell-like CART cells in the final product, and IL-21 supported the expansion of CART cells with a younger phenotype, while IL-2 induced more differentiated CART cells. IL-2 and IL-15-exposed CART cells secreted more proinflammatory cytokines and presented stronger tumor-lysis ability in vitro. However, when tested in vivo, CART cells exposed to IL-2 ex vivo showed the least anti-tumor effect. In contrast, the administration of IL-15 and IL-21 in combination with CART cells in vivo increased their tumor killing capacity. According to our results, IL-7 and IL-15 show promise to promote ex vivo expansion of CART cells, while IL-15 and IL-21 seem better suited for in vivo administration after CART cell infusion. Collectively, these results may have a profound impact on the efficacy of CART cells in both hematologic and solid cancers.

[Progress in clinical studies of chimeric antigen receptor engineered T cells for treatment of childhood cancer]

Nowadays, the 5-year survival rate of childhood cancer patients can be more than 80%, but some patients with relapse and refractory cancers have shown no good response to traditional strategies. Chimeric antigen receptor engineered T (CAR-T) cell therapy is promising for these patients. CAR-T cells recognize the tumor-associated antigens in a non-major histocompatibility complex-restricted manner, so their anti-tumor ability is enhanced. There are four generations of CAR-T cells now. The complete remission rate of pediatric patients with relapse and refractory acute lymphoblastic leukemia can be as high as 90% when treated with CD19-targeting CAR-T cells. Furthermore, CAR-T cell therapy can also be used to bridge to transplantation and donor CAR-T cell infusion can be a strategy to prevent relapse after hematopoietic stem cell transplantation. As to solid tumors, only patients with neuroblastoma present good response to the GD2-targeting CAR-T cell therapy. The toxic or side effects of CAR-T cell therapy include cytokine release syndrome, off-tumor effect, tumor lysis syndrome, and insertion mutation. Although the CD19-targeting CAR-T cell therapy for childhood cancer can result in a high remission rate, the relapse rate is high, including CD19⁺ and CD19^- relapse. The mechanisms for relapse merit further investigatio.

Anti-CD 19 and anti-CD 20 CAR-modified T cells for B-cell malignancies: a systematic review and meta-analysis

Chimeric antigen receptor modified T cells targeting CD19 and CD20 have shown activity in Phase I, II trials of patients with hematological malignancies. We conducted a systematic review and meta-analysis of all published clinical trials studying the role of efficacy as well as safety of CD-19 and CD-20 chimeric antigen receptor-T therapy for B-cell hematologic malignancies. A total of 16 studies with 195 patients were identified. The pooled analysis showed an overall response rate of 61% (118/195) with complete response of 42% (81/195) and partial response of 19% (37/195). Major adverse events were cytokine release syndrome 33%, neurotoxicity 33% and B-cell aplasia 54%. Collectively, the results indicate encouraging response in relapsed/refractory B lymphoma and leukemia, especially in acute lymphoblastic leukemia (ALL) patients.

A new therapeutic potential for cancers: One CAR with 2 different engines!

Tumor cells escape from immune recognition by several mechanisms such as down-regulating of MHC class I molecules, losing of tumor antigens, etc. The purpose of cancer immunotherapy is to robust or reconstruct the capacity of the immune system to recognize and kill tumor cells by overwhelming the mechanisms by which tumors escape the immune response. One of the novel immunotherapeutic strategies were used to potentiate NK- and T cell functions is chimeric antigen receptor (CAR). CARs are composed of an antigen-binding domain of a molecule such as an antibody (that binds to a tumor associated antigens expressed on the surface of tumor cells) and an intracellular T cell activation domain. The CARs provide the recognition of target antigen in a MHC-independent manner. CAR-armed T cells may be unable to kill their targets in the absence of co-stimulators like NK cells. On the other hand, CAR-armed NK cells may also be unable to destroy their targets without receiving help signals from Th cells. Thus, if CAR-armed NK cells use together with CAR-armed T cells, NK cells will be aggregated to the tumor site. Thus, not only CAR T cells will obtain the necessary cytokines/costimulators from NK cells, but also other tumor specific T cells will be primed by recognition of tumor specific antigen (TSA) associated with MHC class I. These new specific primed T cells probably combat against tumor cells which have lost their TAAs that CAR-T cells are redirected to them.

A new insight in chimeric antigen receptor-engineered T cells for cancer immunotherapy

Adoptive cell therapy using chimeric antigen receptor (CAR)-engineered T cells has emerged as a very promising approach to combating cancer. Despite its ability to eliminate tumors shown in some clinical trials, CAR-T cell therapy involves some significant safety challenges, such as cytokine release syndrome (CRS) and “on-target, off-tumor” toxicity, which is related to poor control of the dose, location, and timing of T cell activity. In the past few years, some strategies to avoid the side effects of CAR-T cell therapy have been reported, including suicide gene, inhibitory CAR, dual-antigen receptor, and the use of exogenous molecules as switches to control the CAR-T cell functions. Because of the advances of the CAR paradigm and other forms of cancer immunotherapy, the most effective means of defeating the cancer has become the integration therapy with the combinatorial control system of switchable dual-receptor CAR-T cell and immune checkpoint blockade.

The growing world of CAR T cell trials: a systematic review

In recent years, cancer treatment involving adoptive cell therapy with chimeric antigen receptor (CAR)-modified patient's immune cells has attracted growing interest. Using gene transfer techniques, the patient's T cells are modified ex vivo with a CAR which redirects the T cells toward the cancer cells through an antibody-derived binding domain. The T cells are activated by the CAR primary signaling and costimulatory domains. Such "second generation" CAR T cells induced complete remission of B cell malignancies in the long-term. In this fast-moving field with a growing number of engineered T cell products, we list about 100 currently ongoing trials here that involve CAR T cells targeting hematopoietic malignancies and solid cancer. Major challenges in the further development of the therapy are briefly discussed.

Therapeutic Potential of T Cell Chimeric Antigen Receptors (CARs) in Cancer Treatment: Counteracting Off-Tumor Toxicities for Safe CAR T Cell Therapy

A chimeric antigen receptor (CAR) is a recombinant fusion protein combining an antibody-derived targeting fragment with signaling domains capable of activating T cells. Recent early-phase clinical trials have demonstrated the remarkable ability of CAR-modified T cells to eliminate B cell malignancies. This review describes the choice of target antigens and CAR manipulations to maximize antitumor specificity. Benefits and current limitations of CAR-modified T cells are discussed, with a special focus on the distribution of tumor antigens on normal tissues and the risk of on-target, off-tumor toxicities in the clinical setting. We present current methodologies for pre-evaluating these risks and review the strategies for counteracting potential off-tumor effects. Successful implementation of these approaches will improve the safety and efficacy of CAR T cell therapy and extend the range of cancer patients who may be treated.

The novel anti-CD19 chimeric antigen receptors with humanized scFv (single-chain variable fragment) trigger leukemia cell killing

The molecular design of CARs (Chimeric Antigen Receptors), especially the scFv, has been a major part to use of CAR-T cells for targeted adoptive immunotherapy. To address this issue, we chose a vector backbone encoding a second-generation CAR based on efficacy of a murine scFv-based CAR. Next, we generated a panel of humanized scFvs and tested in vitro for their ability to direct CAR-T cells to specifically lyse, proliferate, and secrete cytokines in response to antigen-bearing targets. Furthermore, in a xenograft model of lymphoma, human T cells expressing humanized scFvs exhibited the same anti-tumor efficacy as those expressing murine scFv and prolonged survival compared with cells expressing control CAR. Therefore, we uncovered CARs expressing humanized scFv domain that contribute the similar enhanced antileukemic efficacy and survival in tumor bearing mice. These results provide the basis for the future clinical studies of CAR-T cells transduced with humanized scFv directed to CD19.

Switch-mediated activation and retargeting of CAR-T cells for B-cell malignancies

Chimeric antigen receptor T (CAR-T) cell therapy has produced impressive results in clinical trials for B-cell malignancies. However, safety concerns related to the inability to control CAR-T cells once infused into the patient remain a significant challenge. Here we report the engineering of recombinant antibody-based bifunctional switches that consist of a tumor antigen-specific Fab molecule engrafted with a peptide neo-epitope, which is bound exclusively by a peptide-specific switchable CAR-T cell (sCAR-T). The switch redirects the activity of the bio-orthogonal sCAR-T cells through the selective formation of immunological synapses, in which the sCAR-T cell, switch, and target cell interact in a structurally defined and temporally controlled manner. Optimized switches specific for CD19 controlled the activity, tissue-homing, cytokine release, and phenotype of sCAR-T cells in a dose-titratable manner in a Nalm-6 xenograft rodent model of B-cell leukemia. The sCAR-T-cell dosing regimen could be tuned to provide efficacy comparable to the corresponding conventional CART-19, but with lower cytokine levels, thereby offering a method of mitigating cytokine release syndrome in clinical translation. Furthermore, we demonstrate that this methodology is readily adaptable to targeting CD20 on cancer cells using the same sCAR-T cell, suggesting that this approach may be broadly applicable to heterogeneous and resistant tumor populations, as well as other liquid and solid tumor antigens.

CD19-Chimeric Antigen Receptor T Cells for Treatment of Chronic Lymphocytic Leukaemia and Acute Lymphoblastic Leukaemia

Adoptive cell therapy (ACT) for cancer represents a promising new treatment modality. ACT based on the administration of cytotoxic T cells genetically engineered to express a chimeric antigen receptor (CAR) recognizing CD19 expressed by B cell malignancies has been shown to induce complete lasting responses in patients with chronic lymphocytic leukaemia (CLL) and acute lymphoblastic leukaemia (ALL). So far, eleven clinical trials including 99 CLL and ALL patients treated with CAR T cells targeting CD19 have been published, and the results from these trials are promising with impressive clinical responses in heavily pretreated patients. Thus, CAR T cell therapy has induced complete responses in both CLL and ALL, and surprisingly, current results indicate that patients with ALL are more prone to respond than are CLL patients. Importantly, the majority of CAR cell studies have observed severe therapy-associated toxicities, which needs attention. Herein we review current data and discuss key aspects of this powerful approach to treat and potentially cure B cell malignancies.

Efficiency of CD19 chimeric antigen receptor-modified T cells for treatment of B cell malignancies in phase I clinical trials: a meta-analysis

Chimeric antigen receptor (CAR) modified T cells targeted CD19 showed promising clinical outcomes in treatment of B cell malignances such as chronic lymphocytic leukemia (CLL), acute lymphoblastic leukemia (ALL) and other indolent lymphomas. However, the clinical benefit varies tremendously among different trials. This meta-analysis investigated the efficacy (response rates and survival time) of CD19-CAR T cells in refractory B cell malignances in Phase I clinical trials. We searched publications between 1991 and 2014 from PubMed and Web of Science. Pooled response rates were calculated using random-effects models. Heterogeneity was investigated by subgroup analysis and meta-regression. Fourteen clinical trials including 119 patients were eligible for response rate evaluation, 62 patients in 12 clinical trials were eligible for progression-free survival analysis. The overall pooled response rate of CD19-CAR T cells was 73% (95% confidence interval [CI]: 46-94%). Significant heterogeneity across estimates of response rates was observed (p < 0.001, I2=88.3%). ALL patients have higher response rate (93%, 95% CI: 65-100%) than CLL (62%, 95% CI: 27-93%) and lymphoma patients (36%, 95% CI: 1-83%). Meta-regression analysis identified lymphodepletion and no IL-2 administrated T cells as two key factors associated with better clinical response. Lymphodepletion and higher infused CAR T cell number were associated with better prognosis. In conclusion, this meta-analysis showed a high clinical response rate of CD19-CAR T cell-based immunotherapy in treatment of refractory B cell malignancies. Lymphodepletion and increasing number of infused CD19-CAR T cells have positive correlations with the clinical efficiency, on the contrary, IL-2 administration to T cells is not recommended.

Rigorous optimization and validation of potent RNA CAR T cell therapy for the treatment of common epithelial cancers expressing folate receptor

Using lentiviral technology, we recently demonstrated that incorporation of CD27 costimulation into CARs greatly improves antitumor activity and T cell persistence. Still, virus-mediated gene transfer is expensive, laborious and enables long-term persistence, creating therapies which cannot be easily discontinued if toxic. To address these concerns, we utilized a non-integrating RNA platform to engineer human T cells to express FRα-specific, CD27 CARs and tested their capacity to eliminate human FRα(+) cancer. Novel CARs comprised of human components were constructed, C4-27z and C4opt-27z, a codon-optimized variant created for efficient expression. Following RNA electroporation, C4-27z and C4opt-27z CAR expression is initially ubiquitous but progressively declines across T cell populations. In addition, C4-27z and C4opt-27z RNA CAR T cells secrete high levels of Th-1 cytokines and display strong cytolytic function against human FRα(+) cancers in a time- and antigen-dependent manner. Further, C4-27z and C4opt-27z CAR T cells exhibit significant proliferation in vivo, facilitate the complete regression of fully disseminated human ovarian cancer xenografts in mice and reduce the progression of solid ovarian cancer. These results advocate for rapid progression of C4opt-27z RNA CAR to the clinic and establish a new paradigm for preclinical optimization and validation of RNA CAR candidates destined for clinical translation.

Adolescent and young adult patients with cancer: a milieu of unique features

Adolescent and young adult (AYA) patients with cancer are a unique category of patients who, depending on age at time of diagnosis, might receive treatment from oncologists specializing either in the treatment of children or adults. In the USA, AYA oncology generally encompasses patients 15-39 years of age. AYA patients with cancer typically present with diseases that span the spectrum from 'paediatric' cancers (such as acute lymphoblastic leukaemia [ALL] and brain tumours) to 'adult' tumours (such as breast cancer and melanoma), as well as cancers that are largely unique to their age group (such as testicular cancer and bone tumours). Research indicates that outcomes of AYA patients with cancer are influenced not only by the treatment provided, but also by factors related to 'host' biology. In addition to the potential biological and cancer-specific differences between AYAs and other patients with cancer, AYA patients also often have disparate access to clinical trials and suffer from a lack of age-appropriate psychosocial support services and health services, which might influence survival as well as overall quality of life. In this Review, these issues are discussed, with a focus on two types of AYA cancer--ALL and melanoma--highlighting findings arising from the use of emerging technologies, such as whole-genome sequencing.

CD19 chimeric antigen receptor T cell therapy for haematological malignancies

T cells can be redirected to recognize tumour antigens by genetic modification to express a chimeric antigen receptor (CAR). These consist of antibody-derived antigen-binding regions linked to T cell signalling elements. CD19 is an ideal target because it is expressed on most B cell malignancies as well as normal B cells but not on other cell types, restricting any 'on target, off tumour' toxicity to B cell depletion. Recent clinical studies involving CD19 CAR-directed T cells have shown unprecedented responses in a range of B cell malignancies, even in patients with chemorefractory relapse. Durable responses have been achieved, although the persistence of modified T cells may be limited. This therapy is not without toxicity, however. Cytokine release syndrome and neurotoxicity appear to be frequent but are treatable and reversible. CAR T cell therapy holds the promise of a tailored cellular therapy, which can form memory and be adapted to the tumour microenvironment. This review will provide a perspective on the currently available data, as well as on future developments in the field.

Fine-tuning Tumor Immunity with Integrin Trans-regulation

Inefficient T-cell homing to tissues limits adoptive T-cell immunotherapy of solid tumors. αLβ2 and α4β1 integrins mediate trafficking of T cells into tissues via engagement of ICAM-1 and VCAM-1, respectively. Inhibiting protein kinase A (PKA)-mediated phosphorylation of α4 integrin in cells results in an increase in αLβ2-mediated migration on mixed ICAM-1-VCAM-1 substrates in vitro, a phenomenon termed "integrin trans-regulation." Here, we created an α4(S988A)-bearing mouse, which precludes PKA-mediated α4 phosphorylation, to examine the effect of integrin trans-regulation in vivo. The α4(S988A) mouse exhibited a dramatic and selective increase in migration of lymphocytes, but not myeloid cells, to sites of inflammation. Importantly, we found that the α4(S988A) mice exhibited a marked increase in T-cell entry into and reduced growth of B16 melanomas, consistent with antitumor roles of infiltrating T cells and progrowth functions of tumor-associated macrophages. Thus, increased α4 trans-regulation of αLβ2 integrin function biases leukocyte emigration toward lymphocytes relative to myeloid cells and enhances tumor immunity.

Design and development of therapies using chimeric antigen receptor-expressing T cells

Investigators developed chimeric antigen receptors (CARs) for expression on T cells more than 25 years ago. When the CAR is derived from an antibody, the resultant cell should combine the desirable targeting features of an antibody (e.g. lack of requirement for major histocompatibility complex recognition, ability to recognize non-protein antigens) with the persistence, trafficking, and effector functions of a T cell. This article describes how the past two decades have seen a crescendo of research which has now begun to translate these potential benefits into effective treatments for patients with cancer. We describe the basic design of CARs, describe how antigenic targets are selected, and the initial clinical experience with CAR-T cells. Our review then describes our own and other investigators' work aimed at improving the function of CARs and reviews the clinical studies in hematological and solid malignancies that are beginning to exploit these approaches. Finally, we show the value of adding additional engineering features to CAR-T cells, irrespective of their target, to render them better suited to function in the tumor environment, and discuss how the safety of these heavily modified cells may be maintained.

Elimination of progressive mammary cancer by repeated administrations of chimeric antigen receptor-modified T cells

Continuous oncogenic processes that generate cancer require an on-going treatment approach to eliminate the transformed cells, and prevent their further development. Here, we studied the ability of T cells expressing a chimeric antibody-based receptor (CAR) to offer a therapeutic benefit for breast cancer induced by erbB-2. We tested CAR-modified T cells (T-bodies) specific to erbB-2 for their antitumor potential in a mouse model overexpressing a human erbB-2 transgene that develops mammary tumors. Comparing the antitumor reactivity of CAR-modified T cells under various therapeutic settings, either prophylactic, prior to tumor development, or therapeutically. We found that repeated administration of CAR-modified T cells is required to eliminate spontaneously developing mammary cancer. Systemic, as well as intratumoral administered CAR-modified T cells accumulated at tumor sites and eventually eliminated the malignant cells. Interestingly, within a few weeks after a single CAR T cells' administration, and rejection of primary lesion, tumors usually relapsed both in treated mammary gland and at remote sites; however, repeated injections of CAR-modified T cells were able to control the secondary tumors. Since spontaneous tumors can arise repeatedly, especially in the case of syndromes characterized by specific susceptibility to cancer, multiple administrations of CAR-modified T cells can serve to control relapsing disease.

Cytokine release syndrome in cancer immunotherapy with chimeric antigen receptor engineered T cells

Adoptive transfer of chimeric antigen receptor (CAR)-engineered T cells is a promising therapy for cancers. However, the safety of this approach is concerned. Cytokine release syndrome (CRS) is a common but lethal complication of CAR-T cell therapy. The development of CRS correlates with CAR structures, tumor type and burden, and patients' genetic polymorphisms. CRS related adverse events may be reduced by designing safer CARs and CAR-T cells and following strict dose-escalation scheme. Timely and effective cytokine-directed treatment with corticosteroid and various cytokine antagonists is important to avoid CRS associated death.

Chimeric antigen receptor-engineered T cells for cancer immunotherapy: progress and challenges

Recent years have witnessed much progress in both basic research and clinical trials regarding cancer immunotherapy with chimeric antigen receptor (CAR)-engineered T cells. The unique structure of CAR endows T cell tumor specific cytotoxicity and resistance to immunosuppressive microenvironment in cancers, which helps patients to better tackle the issue of immunological tolerance. Adoptive immunotherapy (AIT) using this supernatural T cell have gained momentum after decades of intense debates because of the promising results obtained from preclinical models and clinical trials. However, it is very important for us to evaluate thoroughly the challenges/obstacles before widespread clinical application, which clearly warrants more studies to improve our understanding of the mechanism underlying AIT. In this review, we focus on the critical issues related to the clinical outcomes of CAR-based adoptive immunotherapy and discuss the rationales to refine this new cancer therapeutic modality.