Manufacture of T cells using the Sleeping Beauty system to enforce expression of a CD19-specific chimeric antigen receptor

Manufacturing CD20/CD19-targeted iCasp9 regulatable CAR-TSCM cells using a Quantum pBac-based CAR-T engineering system

CD19-targeted chimeric antigen receptor (CAR) T cell therapies have driven a paradigm shift in the treatment of relapsed/refractory B-cell malignancies. However, >50% of CD19-CAR-T-treated patients experience progressive disease mainly due to antigen escape and low persistence. Clinical prognosis is heavily influenced by CAR-T cell function and systemic cytokine toxicities. Furthermore, it remains a challenge to efficiently, cost-effectively, and consistently manufacture clinically relevant numbers of virally engineered CAR-T cells. Using a highly efficient piggyBac transposon-based vector, Quantum pBac™ (qPB), we developed a virus-free cell-engineering system for development and production of multiplex CAR-T therapies. Here, we demonstrate in vitro and in vivo that consistent, robust and functional CD20/CD19 dual-targeted CAR-T stem cell memory (CAR-TSCM) cells can be efficiently produced for clinical application using qPB™. In particular, we showed that qPB™-manufactured CAR-T cells from cancer patients expanded efficiently, rapidly eradicated tumors, and can be safely controlled via an iCasp9 suicide gene-inducing drug. Therefore, the simplicity of manufacturing multiplex CAR-T cells using the qPB™ system has the potential to improve efficacy and broaden the accessibility of CAR-T therapies.

INSPIRED Symposium Part 4B: Chimeric Antigen Receptor T Cell Correlative Studies-Established Findings and Future Priorities

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of B cell malignancies, with multiple CAR T cell products approved for numerous indications by regulatory agencies worldwide. However, significant work remains to be done to enhance these treatments. In March 2023, a group of experts in CAR T cell therapy assembled at the National Institutes of Health in Bethesda, Maryland at the Insights in Pediatric CAR T Cell Immunotherapy: Recent Advances and Future Directions (INSPIRED) Symposium to identify key areas for research for the coming years. In session 4B, correlative studies to be incorporated into future clinical trials and real-world settings were discussed. Active areas of research identified included (1) optimizing CAR T cell product manufacturing; (2) ensuring adequate lymphodepletion prior to CAR T cell administration; (3) overcoming immunoregulatory cells and tumor stroma present in the tumor microenvironment, particularly in solid tumors; (4) understanding tumor intrinsic properties that lead to CAR T cell immunotherapy resistance; and (5) uncovering biomarkers predictive of treatment resistance, treatment durability, or immune-related adverse events. Here we review the results of previously published clinical trials and real-world studies to summarize what is currently known about each of these topics. We then outline priorities for future research that we believe will be important for improving our understanding of CAR T cell therapy and ultimately leading to better outcomes for patients.

Engineered CAR-T cells: An immunotherapeutic approach for cancer treatment and beyond

Chimeric Antigen Receptor (CAR) T cell therapy is a type of adoptive immunotherapy that offers a promising avenue for enhancing cancer treatment since traditional cancer treatments like chemotherapy, surgery, and radiation therapy have proven insufficient in completely eradicating tumors, despite the relatively positive outcomes. It has been observed that CAR-T cell therapy has shown promising results in treating the majority of hematological malignancies but also have a wide scope for other cancer types. CAR is an extra receptor on the T-cell that helps to increase and accelerate tumor destruction by efficiently activating the immune system. It is made up of three domains, the ectodomain, transmembrane, and the endodomain. The ectodomain is essential for antigen recognition and binding, whereas the co-stimulatory signal is transduced by the endodomain. To date, the Food and Drug Administration (FDA) has granted approval for six CAR-T cell therapies. However, despite its remarkable success, CAR-T therapy is associated with numerous adverse events and has certain limitations. This chapter focuses on the structure and function of the CAR domain, various generations of CAR, and the process of CAR-T cell development, adverse effects, and challenges in CAR-T therapy. CAR-T cell therapy also has scopes in other disease conditions which include systemic lupus erythematosus, multiple sclerosis, and myocardial fibrosis, etc.

A Nonviral piggyBac Transposon-Mediated Method to Generate Large-Scale CAR-NK Cells from Human Peripheral Blood Primary NK Cells

With the inherent antitumor function and unique "off-the-shelf" potential, genetically engineered human natural killer (NK) cells with chimeric antigen receptors (CARs) bear great promise for the treatment of multiple hematological malignancies and solid tumors. Current methods of producing large-scale CAR-NK cells mainly rely on mRNA transfection and viral vector transduction. However, mRNA CAR-NK cells were not stable in CAR expression while viral vector transduction mostly ended up with low efficiency. In this chapter, we described an optimized protocol to generate CAR-NK cells by using the piggyBac transposon system via electroporation and to further expand these engineered CAR-NK cells in a large scale together with artificial antigen-presenting feeder cells. This method can stably engineer human primary NK cells with high efficiency and supply sufficient scale of engineered CAR-NK cells for the future possible clinical applications.

Microphysiological systems for solid tumor immunotherapy: opportunities and challenges

Immunotherapy remains more effective for hematologic tumors than for solid tumors. One of the main challenges to immunotherapy of solid tumors is the immunosuppressive microenvironment these tumors generate, which limits the cytotoxic capabilities of immune effector cells (e.g., cytotoxic T and natural killer cells). This microenvironment is characterized by hypoxia, nutrient starvation, accumulated waste products, and acidic pH. Tumor-hijacked cells, such as fibroblasts, macrophages, and T regulatory cells, also contribute to this inhospitable microenvironment for immune cells by secreting immunosuppressive cytokines that suppress the antitumor immune response and lead to immune evasion. Thus, there is a strong interest in developing new drugs and cell formulations that modulate the tumor microenvironment and reduce tumor cell immune evasion. Microphysiological systems (MPSs) are versatile tools that may accelerate the development and evaluation of these therapies, although specific examples showcasing the potential of MPSs remain rare. Advances in microtechnologies have led to the development of sophisticated microfluidic devices used to recapitulate tumor complexity. The resulting models, also known as microphysiological systems (MPSs), are versatile tools with which to decipher the molecular mechanisms driving immune cell antitumor cytotoxicity, immune cell exhaustion, and immune cell exclusion and to evaluate new targeted immunotherapies. Here, we review existing microphysiological platforms to study immuno-oncological applications and discuss challenges and opportunities in the field.

Rapid generation of CD19 CAR-T cells by minicircle DNA enables anti-tumor activity and prevents fatal CAR-B leukemia

Manufacturing chimeric antigen receptor (CAR)-T cellsusing viral vectors is expensive and time-consuming. In addition, during viral transduction, genes encoding CARs are randomly integrated into the genome, which can cause oncogenesis or produce devastating CARtumor cells. Here, using a virus-free and non-transgenic minicircle DNA (mcDNA) vector, we enabledthe rapid generation of CD19 CAR-T cells within two days. Furthermore, we demonstrated in vitro and in xenograft models that the antitumor effects of CD19 CAR-T cells produced by mcDNA are as effective as those produced by viral vectors. Finally, we showed that our manufacturing process avoids the production of fatal CARtumor cells. Taken together, we have provided a fast, effective, and therapeutically safe method for generating CD19 CAR-T cells for the treatment of leukemia.

Updates on global epidemiology, risk and prognostic factors of gastric cancer

Gastric cancer (GC) is defined as the primary epithelial malignancy derived from the stomach, and it is a complicated and heterogeneous disease with multiple risk factors. Despite its overall declining trend of incidence and mortality in various countries over the past few decades, GC remains the fifth most common malignancy and the fourth leading cause of cancer-related death globally. Although the global burden of GC has shown a significant downward trend, it remains severe in certain areas, such as Asia. GC ranks third in incidence and mortality among all cancer types in China, and it accounts for nearly 44.0% and 48.6% of new GC cases and GC-related deaths in the world, respectively. The regional differences in GC incidence and mortality are obvious, and annual new cases and deaths are increasing rapidly in some developing regions. Therefore, early preventive and screening strategies for GC are urgently needed. The clinical efficacies of conventional treatments for GC are limited, and the developing understanding of GC pathogenesis has increased the demand for new therapeutic regimens, including immune checkpoint inhibitors, cell immunotherapy and cancer vaccines. The present review describes the epidemiology of GC worldwide, especially in China, summarizes its risk and prognostic factors, and focuses on novel immunotherapies to develop therapeutic strategies for the management of GC patients.

Systematic Review on CAR-T Cell Clinical Trials Up to 2022: Academic Center Input

The development of Chimeric Antigen Receptor T cells therapy initiated by the United States and China is still currently led by these two countries with a high number of clinical trials, with Europe lagging in launching its first trials. In this systematic review, we wanted to establish an overview of the production of CAR-T cells in clinical trials around the world, and to understand the causes of this delay in Europe. We particularly focused on the academic centers that are at the heart of research and development of this therapy. We counted 1087 CAR-T cells clinical trials on ClinicalTrials.gov (Research registry ID: reviewregistry1542) on the date of 25 January 2023. We performed a global analysis, before analyzing the 58 European trials, 34 of which sponsored by academic centers. Collaboration between an academic and an industrial player seems to be necessary for the successful development and application for marketing authorization of a CAR-T cell, and this collaboration is still cruelly lacking in European trials, unlike in the leading countries. Europe, still far behind the two leading countries, is trying to establish measures to lighten the regulations surrounding ATMPs and to encourage, through the addition of fundings, clinical trials involving these treatments.

Current strategies employed in the manipulation of gene expression for clinical purposes

Abnormal gene expression level or expression of genes containing deleterious mutations are two of the main determinants which lead to genetic disease. To obtain a therapeutic effect and thus to cure genetic diseases, it is crucial to regulate the host's gene expression and restore it to physiological conditions. With this purpose, several molecular tools have been developed and are currently tested in clinical trials. Genome editing nucleases are a class of molecular tools routinely used in laboratories to rewire host's gene expression. Genome editing nucleases include different categories of enzymes: meganucleses (MNs), zinc finger nucleases (ZFNs), clustered regularly interspaced short palindromic repeats (CRISPR)- CRISPR associated protein (Cas) and transcription activator-like effector nuclease (TALENs). Transposable elements are also a category of molecular tools which includes different members, for example Sleeping Beauty (SB), PiggyBac (PB), Tol2 and TcBuster. Transposons have been used for genetic studies and can serve as gene delivery tools. Molecular tools to rewire host's gene expression also include episomes, which are divided into different categories depending on their molecular structure. Finally, RNA interference is commonly used to regulate gene expression through the administration of small interfering RNA (siRNA), short hairpin RNA (shRNA) and bi-functional shRNA molecules. In this review, we will describe the different molecular tools that can be used to regulate gene expression and discuss their potential for clinical applications. These molecular tools are delivered into the host's cells in the form of DNA, RNA or protein using vectors that can be grouped into physical or biochemical categories. In this review we will also illustrate the different types of payloads that can be used, and we will discuss recent developments in viral and non-viral vector technology.

CAR-T cell potency: from structural elements to vector backbone components

Chimeric antigen receptor (CAR) T cell therapy, in which a patient’s own T lymphocytes are engineered to recognize and kill cancer cells, has achieved remarkable success in some hematological malignancies in preclinical and clinical trials, resulting in six FDA-approved CAR-T products currently available in the market. Once equipped with a CAR construct, T cells act as living drugs and recognize and eliminate the target tumor cells in an MHC-independent manner. In this review, we first described all structural modular of CAR in detail, focusing on more recent findings. We then pointed out behind-the-scene elements contributing to CAR expression and reviewed how CAR expression can be drastically affected by the elements embedded in the viral vector backbone.

Chimeric Antigen Receptor T-Cells: An Overview of Concepts, Applications, Limitations, and Proposed Solutions

Adaptive immunity, orchestrated by B-cells and T-cells, plays a crucial role in protecting the body from pathogenic invaders and can be used as tools to enhance the body's defense mechanisms against cancer by genetically engineering these immune cells. Several strategies have been identified for cancer treatment and evaluated for their efficacy against other diseases such as autoimmune and infectious diseases. One of the most advanced technologies is chimeric antigen receptor (CAR) T-cell therapy, a pioneering therapy in the oncology field. Successful clinical trials have resulted in the approval of six CAR-T cell products by the Food and Drug Administration for the treatment of hematological malignancies. However, there have been various obstacles that limit the use of CAR T-cell therapy as the first line of defense mechanism against cancer. Various innovative CAR-T cell therapeutic designs have been evaluated in preclinical and clinical trial settings and have demonstrated much potential for development. Such trials testing the suitability of CARs against solid tumors and HIV are showing promising results. In addition, new solutions have been proposed to overcome the limitations of this therapy. This review provides an overview of the current knowledge regarding this novel technology, including CAR T-cell structure, different applications, limitations, and proposed solutions.

Generation of CAR-T cells using lentiviral vectors

Cancer immunotherapy is nowadays largely focused on the development of therapeutic antibodies and chimeric antigen receptors (CARs). Two CARs targeting CD19 have been approved recently for the treatment of some hematological malignancies. This demonstrates the capability of engineered CAR T cells in generating effective tumor responses. Furthermore, several hundred ongoing clinical trials are exploring the feasibility of CAR-based approaches to target tumor-associated antigens in solid tumors. However, there still remain significant challenges and limitations in the design and production of CAR-modified T cells that need to be addressed, such as more effective transduction methods, expression and exhaustion issues, reliable in vitro and in vivo characterization methods, etc. Here we describe current techniques for generating CAR T cells using lentiviral vectors as well as detailed protocols for their functional characterization.

Generation of CAR-T Cells with Sleeping Beauty Transposon Gene Transfer

Human T lymphocytes that transgenically express a chimeric antigen receptor (CAR) have proven efficacy and safety in gene- and cell-based immunotherapy of certain hematological cancers. Appropriate gene vectors and methods of genetic engineering are required for therapeutic cell products to be biologically potent and their manufacturing to be economically viable. Transposon-based gene transfer satisfies these needs, and is currently being evaluated in clinical trials. In this protocol we describe the basic Sleeping Beauty (SB) transposon vector components required for stable gene integration in human cells, with special emphasis on minicircle DNA vectors and the use of synthetic mRNA. We provide a protocol for functional validation of the vector components in cultured human cell lines on the basis of fluorescent reporter gene expression. Finally, we provide a protocol for CAR-T cell engineering and describe assays that address transgene expression, biological potency and genomic vector copy numbers in polyclonal cell populations. Because transposons allow virus-free gene transfer with naked nucleic acids, the protocol can be adopted by any laboratory equipped with biological safety level S1 facilities.

piggyBac system to co-express NKG2D CAR and IL-15 to augment the in vivo persistence and anti-AML activity of human peripheral blood NK cells

Promising progress has been made in adoptive transfer of allogeneic natural killer (NK) cells to treat relapsed or refractory acute myeloid leukemia (AML). In this regard, chimeric antigen receptor (CAR)-modification of NK cells is considered as a compelling approach to augment the specificity and cytotoxicity of NK cells against AML. Using a non-viral piggyBac transposon technology and human peripheral blood-derived primary NK cells, we generated CAR-NK cells to target NKG2D ligands and demonstrated their in vitro activity in lysing cancer cells expressing the ligands and in vivo efficacy in inhibiting tumor growth in a xenograft KG-1 AML model. We further generated CAR-NK cells co-expressing transgenes for the NKG2D CAR and interleukin-15 (IL-15). The ectopic expression of IL-15 improved the in vitro and in vivo persistence of NKG2D CAR-NK cells, leading to enhanced in vivo tumor control and significant prolongation of mouse survival in the KG-1 AML model. Collectively, our findings demonstrate the ectopic expression of IL-15 as an important means to improve the antileukemic activity of NKG2D CAR-NK cells. Our study further illustrates the feasibility of using the piggyBac non-viral platform as an efficient and cost-effective way for CAR-NK cell manufacturing.

T Cell Engaging Immunotherapies, Highlighting Chimeric Antigen Receptor (CAR) T Cell Therapy

In the past decade, chimeric antigen receptor (CAR) T cell technology has revolutionized cancer immunotherapy. This strategy uses synthetic CARs to redirect the patient's own immune cells to recognize specific antigens expressed on the surface of tumor cells. The unprecedented success of anti-CD19 CAR T cell therapy against B cell malignancies has resulted in its approval by the US Food and Drug Administration (FDA) in 2017. However, major scientific challenges still remain to be addressed for the broad use of CAR T cell therapy. These include severe toxicities, limited efficacy against solid tumors, and immune suppression in the hostile tumor microenvironment. Furthermore, CAR T cell therapy is a personalized medicine of which the production is time- and resource-intensive, which makes it very expensive. All these factors drive new innovations to engineer more powerful CAR T cells with improved antitumor activity, which are reviewed in this manuscript.

A nonviral, nonintegrating DNA nanovector platform for the safe, rapid, and persistent manufacture of recombinant T cells

The compelling need to provide adoptive cell therapy (ACT) to an increasing number of oncology patients within a meaningful therapeutic window makes the development of an efficient, fast, versatile, and safe genetic tool for creating recombinant T cells indispensable. In this study, we used nonintegrating minimally sized DNA vectors with an enhanced capability of generating genetically modified cells, and we demonstrate that they can be efficiently used to engineer human T lymphocytes. This vector platform contains no viral components and is capable of replicating extrachromosomally in the nucleus of dividing cells, providing persistent transgene expression in human T cells without affecting their behavior and molecular integrity. We use this technology to provide a manufacturing protocol to quickly generate chimeric antigen receptor (CAR)-T cells at clinical scale in a closed system and demonstrate their enhanced anti-tumor activity in vitro and in vivo in comparison to previously described integrating vectors.

CAR T-Cell Production Using Nonviral Approaches

Chimeric antigen receptor T-cells (CAR T-cells) represent a novel and promising approach in cancer immunotherapy. According to the World Health Organization (WHO), the number of oncological patients is steadily growing in developed countries despite immense progress in oncological treatments, and the prognosis of individual patients is still relatively poor. Exceptional results have been recorded for CAR T-cell therapy in patients suffering from B-cell malignancies. This success opens up the possibility of using the same approach for other types of cancers. To date, the most common method for CAR T-cell generation is the use of viral vectors. However, dealing with virus-derived vectors brings possible obstacles in the CAR T-cell manufacturing process owing to strict regulations and high cost demands. Alternative approaches may facilitate further development and the transfer of the method to clinical practice. The most promising substitutes for virus-derived vectors are transposon-derived vectors, most commonly sleeping beauty, which offer great coding capability and a safe integration profile while maintaining a relatively low production cost. This review is aimed at summarizing the state of the art of nonviral approaches in CAR T-cell generation, with a unique perspective on the conditions in clinical applications and current Good Manufacturing Practice. If CAR T-cell therapy is to be routinely used in medical practice, the manufacturing cost and complexity need to be as low as possible, and transposon-based vectors seem to meet these criteria better than viral-based vectors.

CAR T cell therapy as a promising approach in cancer immunotherapy: challenges and opportunities

BACKGROUND

Chimeric antigen receptor (CAR)-modified T cell therapy has shown great potential in the immunotherapy of patients with hematologic malignancies. In spite of this striking achievement, there are still major challenges to overcome in CAR T cell therapy of solid tumors, including treatment-related toxicity and specificity. Also, other obstacles may be encountered in tackling solid tumors, such as their immunosuppressive microenvironment, the heterogeneous expression of cell surface markers, and the cumbersome arrival of T cells at the tumor site. Although several strategies have been developed to overcome these challenges, aditional research aimed at enhancing its efficacy with minimum side effects, the design of precise yet simplified work flows and the possibility to scale-up production with reduced costs and related risks is still warranted.

CONCLUSIONS

Here, we review main strategies to establish a balance between the toxicity and activity of CAR T cells in order to enhance their specificity and surpass immunosuppression. In recent years, many clinical studies have been conducted that eventually led to approved products. To date, the FDA has approved two anti-CD19 CAR T cell products for non-Hodgkin lymphoma therapy, i.e., axicbtagene ciloleucel and tisagenlecleucel. With all the advances that have been made in the field of CAR T cell therapy for hematologic malignancies therapy, ongoing studies are focused on optimizing its efficacy and specificity, as well as reducing the side effects. Also, the efforts are poised to broaden CAR T cell therapeutics for other cancers, especially solid tumors.

Designed improvement to T-cell immunotherapy by multidimensional single cell profiling

BACKGROUND

Adoptive cell therapy based on the infusion of chimeric antigen receptor (CAR) T cells has shown remarkable efficacy for the treatment of hematologic malignancies. The primary mechanism of action of these infused T cells is the direct killing of tumor cells expressing the cognate antigen. However, understanding why only some T cells are capable of killing, and identifying mechanisms that can improve killing has remained elusive.

METHODS

To identify molecular and cellular mechanisms that can improve T-cell killing, we utilized integrated high-throughput single-cell functional profiling by microscopy, followed by robotic retrieval and transcriptional profiling.

RESULTS

With the aid of mathematical modeling we demonstrate that non-killer CAR T cells comprise a heterogeneous population that arise from failure in each of the discrete steps leading to the killing. Differential transcriptional single-cell profiling of killers and non-killers identified CD137 as an inducible costimulatory molecule upregulated on killer T cells. Our single-cell profiling results directly demonstrate that inducible CD137 is feature of killer (and serial killer) T cells and this marks a different subset compared with the CD107apos (degranulating) subset of CAR T cells. Ligation of the induced CD137 with CD137 ligand (CD137L) leads to younger CD19 CAR T cells with sustained killing and lower exhaustion. We genetically modified CAR T cells to co-express CD137L, in trans, and this lead to a profound improvement in anti-tumor efficacy in leukemia and refractory ovarian cancer models in mice.

CONCLUSIONS

Broadly, our results illustrate that while non-killer T cells are reflective of population heterogeneity, integrated single-cell profiling can enable identification of mechanisms that can enhance the function/proliferation of killer T cells leading to direct anti-tumor benefit.

Chimeric Antigen Receptor (CAR) T Cell Therapy for Cancer. Challenges and Opportunities: An Overview

The use of immunotherapy as an alternative treatment for cancer patients has become of great interest in the scientific community as it is required to overcome many of the currently unsolved problems such as tumor escape, immunosuppression and unwanted unspecific toxicity. The use of chimeric antigen receptor T cells has been a very successful strategy in some hematologic malignancies. However, the application of CAR T cells has been limited to solid tumors, and this has aimed the development of new generation of CARs with enhanced effectivity and specificity. Here, we review the state of the art of CAR T cell therapy with special emphasis on the current challenges and opportunities.

Advances and Challenges of CAR T Cells in Clinical Trials

As a specifically programmable, living immunotherapeutic drug, chimeric antigen receptor (CAR)-modified T cells are providing an alternative treatment option for a broad variety of diseases including so far refractory cancer. By recognizing a tumor-associated antigen, the CAR triggers an anti-tumor response of engineered patient's T cells achieving lasting remissions in the treatment of leukemia and lymphoma. During the last years, significant progress was made in optimizing the CAR design, in manufacturing CAR-engineered T cells, and in the clinical management of patients showing promise to establish adoptive CAR T cell therapy as an effective treatment option in the forefront.

Mechanisms of resistance to CAR T cell therapies

Chimeric antigen receptor (CAR)-engineered T cells have demonstrated remarkable success in the treatment of B cell malignancies. FDA approval of these therapies represents a watershed moment in the development of therapies for cancer. Despite the successes of the last decade, many patients will unfortunately not experience durable responses to CAR therapy. Emerging research has shed light on the biology responsible for these failures, and further highlighted the hurdles to broader success. Here, we review the recent research identifying how interactions between cancer cells and engineered immune cells result in resistance to CAR therapies.

Production of CAR T-cells by GMP-grade lentiviral vectors: latest advances and future prospects

Chimeric antigen receptor (CAR) T-cells represent a paradigm shift in cancer immunotherapy and a new milestone in the history of oncology. In 2017, the Food and Drug Administration approved two CD19-targeted CAR T-cell therapies (Kymriah™, Novartis, and Yescarta™, Kite Pharma/Gilead Sciences) that have remarkable efficacy in some B-cell malignancies. The CAR approach is currently being evaluated in multiple pivotal trials designed for the immunotherapy of hematological malignancies as well as solid tumors. To generate CAR T-cells ex vivo, lentiviral vectors (LVs) are particularly appealing due to their ability to stably integrate relatively large DNA inserts, and to efficiently transduce both dividing and nondividing cells. This review discusses the latest advances and challenges in the design and production of CAR T-cells, and the good manufacturing practices (GMP)-grade production process of LVs used as a gene transfer vehicle. New developments in the application of CAR T-cell therapy are also outlined with particular emphasis on next-generation allogeneic CAR T-cells.

Novel biomanufacturing platform for large-scale and high-quality human T cells production

The adoptive transfer of human T cells or genetically-engineered T cells with cancer-targeting receptors has shown tremendous promise for eradicating tumors in clinical trials. The objective of this study was to develop a novel T cell biomanufacturing platform using stirred-tank bioreactor for large-scale and high-quality cellular production. First, various factors, such as bioreactor parameters, media, supplements, stimulation, seed age, and donors, were investigated. A serum-free fed-batch bioproduction process was developed to achieve 1000-fold expansion within 8 days after first stimulation and another 500-fold expansion with second stimulation. Second, this biomanufacturing process was successfully scaled up in bioreactor with dilution factor of 10, and the robustness and reproducibility of the process was confirmed by the inclusion of different donors' T cells of various qualities. Finally, T cell quality was monitored using 12 surface markers and 3 intracellular cytokines as the critical quality assessment criteria in early, middle and late stages of cell production. In this study, a new biomanufacturing platform was created to produce reliable, reproducible, high-quality, and large-quantity (i.e. > 5 billion) human T cells in stirred-tank bioreactor. This platform is compatible with the production systems of monoclonal antibodies, vaccines, and other therapeutic cells, which provides not only the proof-of-concept but also the ready-to-use new approach of T cell expansion for clinical immune therapy.

CAR T Cells: A Snapshot on the Growing Options to Design a CAR

Adoptive cell therapy of malignant diseases with chimeric antigen receptor (CAR) modified T cells rapidly advanced from pre-clinical models to commercial approvals within 2 decades. CARs redirect patient's T cells towards cancer cells and activate the engineered cells for a cytolytic attack resulting in the destruction of the cognate target cell. CAR T cells have demonstrated their powerful capacities in inducing complete and lasting remissions of leukemia/lymphoma in an increasing number of trials worldwide. Since the early 90's, the design of CARs went through various steps of optimization until the very recent developments which include CARs with logic gating in the recognition of antigen patterns on target cells and TRUCKs with a target recognition induced delivery of immune modulating agents. Here we review the generations in CAR design, the impact of specific modifications, the strategies to improve the safety of CAR T cell therapy, and the challenges to adapt the CAR design for broader applications.

Manufacturing chimeric antigen receptor T cells: issues and challenges

Clinical trials of adoptively transferred CD19 chimeric antigen receptor (CAR) T cells have delivered unprecedented responses in patients with relapsed refractory B-cell malignancy. These results have prompted Food and Drug Administration (FDA) approval of two CAR T-cell products in this high-risk patient population. The widening range of indications for CAR T-cell therapy and increasing patient numbers present a significant logistical challenge to manufacturers aiming for reproducible delivery systems for high-quality clinical CAR T-cell products. This review discusses current and novel CAR T-cell processing methodologies and the quality control systems needed to meet the increasing clinical demand for these exciting new therapies.

Off the shelf T cell therapies for hematologic malignancies

Adoptive transfer of autologous CAR-T cells can induce durable remissions in patients with relapsed/refractory hematologic malignancies. However, multiple challenges exist for manufacturing CAR-T cells from patients with advanced disease including inability to manufacture a product, disease progression or death while waiting for the CAR-T product to be available, and heterogeneity among autologous CAR-T products that contributes to unpredictable and variable clinical activity. Healthy donor T cells can provide a source for production of universal CAR-T cells when combined with gene editing to prevent expression of endogenous TCRs and avoid generation of GvHD in HLA mismatched recipients. Additional gene edits can be included to impart resistance to immunosuppression or improve trafficking to tumor sites. Recent advances in cell manufacturing and analytics technology can provide for consistent batch to batch manufacturing of gene edited allogeneic CAR-T cells in sufficient quantity to treat thousands of patients when needed as off the shelf products.

A guide to manufacturing CAR T cell therapies

In recent years, chimeric antigen receptor (CAR) modified T cells have been used as a treatment for haematological malignancies in several phase I and II trials and with Kymriah of Novartis and Yescarta of KITE Pharma, the first CAR T cell therapy products have been approved. Promising clinical outcomes have yet been tempered by the fact that many therapies may be prohibitively expensive to manufacture. The process is not yet defined, far from being standardised and often requires extensive manual handling steps. For academia, big pharma and contract manufacturers it is difficult to obtain an overview over the process strategies and their respective advantages and disadvantages. This review details current production processes being used for CAR T cells with a particular focus on efficacy, reproducibility, manufacturing costs and release testing. By undertaking a systematic analysis of the manufacture of CAR T cells from reported clinical trial data to date, we have been able to quantify recent trends and track the uptake of new process technology. Delivering new processing options will be key to the success of the CAR-T cells ensuring that excessive manufacturing costs do not disrupt the delivery of exciting new therapies to the wide possible patient cohort.

Bioengineering Solutions for Manufacturing Challenges in CAR T Cells

The next generation of therapeutic products to be approved for the clinic is anticipated to be cell therapies, termed "living drugs" for their capacity to dynamically and temporally respond to changes during their production ex vivo and after their administration in vivo. Genetically engineered chimeric antigen receptor (CAR) T cells have rapidly developed into powerful tools to harness the power of immune system manipulation against cancer. Regulatory agencies are beginning to approve CAR T cell therapies due to their striking efficacy in treating some hematological malignancies. However, the engineering and manufacturing of such cells remains a challenge for widespread adoption of this technology. Bioengineering approaches including biomaterials, synthetic biology, metabolic engineering, process control and automation, and in vitro disease modeling could offer promising methods to overcome some of these challenges. Here, we describe the manufacturing process of CAR T cells, highlighting potential roles for bioengineers to partner with biologists and clinicians to advance the manufacture of these complex cellular products under rigorous regulatory and quality control.

The Evolution and Future of CAR T Cells for B-Cell Acute Lymphoblastic Leukemia

Several CAR T designs with CD19 specificity have been associated with consistent responses in clinical trials with complete remission (CR) rates ranging from 70-90%. Relevant challenges remain to be addressed, such as production time, early loss of CAR T cells, relapse due to loss of the target antigen, and prevention of severe cytokine release syndrome and neurotoxicity. This review describes constructs, clinical trial results, side effects, and future direction of CAR T-cell therapy in B-ALL.

Emerging trends in the immunotherapy of pancreatic cancer

Pancreatic cancer (PC) is the fourth leading cause of cancer-related deaths in the U.S., claiming approximately 43,000 lives every year. Much like other solid tumors, PC evades the host immune surveillance by manipulating immune cells to establish an immunosuppressive tumor microenvironment (TME). Therefore, targeting and reinstating the patient's immune system could serve as a powerful therapeutic tool. Indeed, immunotherapy has emerged in recent years as a potential adjunct treatment for solid tumors including PC. Immunotherapy modulates the host's immune response to tumor-associated antigens (TAAs), eradicates cancer cells by reducing host tolerance to TAAs and provides both short- and long-term protection against the disease. Passive immunotherapies like monoclonal antibodies or engineered T-cell based therapies directly target tumor cells by recognizing TAAs. Active immunotherapies, like cancer vaccines, on the other hand elicit a long-lasting immune response via activation of the patient's immune cells against cancer cells. Several immunotherapy strategies have been tested for anti-tumor responses alone and in combination with standard care in multiple preclinical and clinical studies. In this review, we discuss various immunotherapy strategies used currently and their efficacy in abrogating self-antigen tolerance and immunosuppression, as well as their ability to eradicate PC.

Gene Therapy with the Sleeping Beauty Transposon System

The widespread clinical implementation of gene therapy requires the ability to stably integrate genetic information through gene transfer vectors in a safe, effective, and economical manner. The latest generation of Sleeping Beauty (SB) transposon vectors fulfills these requirements, and may overcome limitations associated with viral gene transfer vectors and transient nonviral gene delivery approaches that are prevalent in ongoing clinical trials. The SB system enables high-level stable gene transfer and sustained transgene expression in multiple primary human somatic cell types, thereby representing a highly attractive gene transfer strategy for clinical use. Here, we review the most important aspects of using SB for gene therapy, including vectorization as well as genomic integration features. We also illustrate the path to successful clinical implementation by highlighting the application of chimeric antigen receptor (CAR)-modified T cells in cancer immunotherapy.

Chimeric Antigen Receptor T cells for B Cell Neoplasms: Choose the Right CAR for You

Genetic redirection of T lymphocytes allows us to unleash these potent cellular immune effectors against cancer. Chimeric antigen receptor (CAR) T cells are the best-in-class example that genetic engineering of T cells can lead to deep and durable responses, as has been shown in several clinical trials for CD19+ B cell malignancies. As a consequence, in the last few years, several academic institutions and commercial partners have started developing anti-CD19 CAR T cell products. Although most of these T cell products are highly effective in vivo, basic differences among them can generate different performance characteristics and thereby impact their long-term clinical outcome. Several strategies are being implemented in order to solve the current open issues of CART19 therapy: (i) increasing efficacy against indolent B cell leukemias and lymphomas, (ii) avoiding or preventing antigen-loss relapses, (iii) reducing and managing toxicity, and (iv) bringing this CART therapy to routine clinical practice. The field of CART therapies is thriving, and exciting new avenues are opening for both scientists and patients.

The Multi-Purpose Tool of Tumor Immunotherapy: Gene-Engineered T Cells

A detailed summary of the published clinical trials of chimeric antigen receptor T cells (CAR-T) and TCR-transduced T cells (TCR-T) was constructed to understand the development trend of adoptive T cell therapy (ACT). In contrast to TCR-T, the number of CAR-T clinical trials has increased dramatically in China in the last three years. The ACT seems to be very prosperous. But, the multidimensional interaction of tumor, tumor associated antigen (TAA) and normal tissue exacerbates the uncontrolled outcome of T cells gene therapy. It reminds us the importance that optimizing treatment security to prevent the fatal serious adverse events. How to balance the safety and effectiveness of the ACT? At least six measures can potentially optimize the safety of ACT. At the same time, with the application of gene editing techniques, more endogenous receptors are disrupted while more exogenous receptors are expressed on T cells. As a multi-purpose tool of tumor immunotherapy, gene-engineered T cells (GE-T) have been given different functional weapons. A network which is likely to link radiation therapy, tumor vaccines, CAR-T and TCR-T is being built. Moreover, more and more evidences indicated that the combination of the ACT and other therapies would further enhance the anti-tumor capacity of the GE-T.

An Efficient Electroporation Protocol for the Genetic Modification of Mammalian Cells

Genetic modification of cell lines and primary cells is an expensive and cumbersome approach, often involving the use of viral vectors. Electroporation using square-wave generating devices, like Lonza's Nucleofector, is a widely used option, but the costs associated with the acquisition of electroporation kits and the transient transgene expression might hamper the utility of this methodology. In the present work, we show that our in-house developed buffers, termed Chicabuffers, can be efficiently used to electroporate cell lines and primary cells from murine and human origin. Using the Nucleofector II device, we electroporated 14 different cell lines and also primary cells, like mesenchymal stem cells and cord blood CD34+, providing optimized protocols for each of them. Moreover, when combined with sleeping beauty-based transposon system, long-term transgene expression could be achieved in all types of cells tested. Transgene expression was stable and did not interfere with CD34+ differentiation to committed progenitors. We also show that these buffers can be used in CRISPR-mediated editing of PDCD1 gene locus in 293T and human peripheral blood mononuclear cells. The optimized protocols reported in this study provide a suitable and cost-effective platform for the genetic modification of cells, facilitating the widespread adoption of this technology.

Genome Editing Techniques and Their Therapeutic Applications

Fueled by advances in the field of genetics, the methods available to edit DNA sequences in living cells have continued to develop steadily. These technologies directly impact the fields of gene and cell therapy, where changes in the DNA sequence of target cells offer a route to correct genetic diseases and manipulate disorders like cancer. We review here the expanding menu of genome editing techniques and how they are being applied to therapeutic targets. The methods encompass a myriad of approaches to modify the covalent structure of DNA, including the targeted creation of double-strand breaks that can catalyze genomic changes, as well as the use of retroviruses and transposons to mediate gene addition, recombinases for sequence-specific gene addition and deletion, and base repair for direct sequence changes. The continued growth of the exciting field of genome editing is opening new possibilities for therapeutic intervention.

DNA Transposition at Work

DNA transposons are defined segments of DNA that are able to move from one genomic location to another. Movement is facilitated by one or more proteins, called the transposase, typically encoded by the mobile element itself. Here, we first provide an overview of the classification of such mobile elements in a variety of organisms. From a mechanistic perspective, we have focused on one particular group of DNA transposons that encode a transposase with a DD(E/D) catalytic domain that is topologically similar to RNase H. For these, a number of three-dimensional structures of transpososomes (transposase-nucleic acid complexes) are available, and we use these to describe the basics of their mechanisms. The DD(E/D) group, in addition to being the largest and most common among all DNA transposases, is the one whose members have been used for a wide variety of genomic applications. Therefore, a second focus of the article is to provide a nonexhaustive overview of transposon applications. Although several non-transposon-based approaches to site-directed genome modifications have emerged in the past decade, transposon-based applications are highly relevant when integration specificity is not sought. In fact, for many applications, the almost-perfect randomness and high frequency of integration make transposon-based approaches indispensable.

Sleeping Beauty transposition: from biology to applications

Sleeping Beauty (SB) is the first synthetic DNA transposon that was shown to be active in a wide variety of species. Here, we review studies from the last two decades addressing both basic biology and applications of this transposon. We discuss how host-transposon interaction modulates transposition at different steps of the transposition reaction. We also discuss how the transposon was translated for gene delivery and gene discovery purposes. We critically review the system in clinical, pre-clinical and non-clinical settings as a non-viral gene delivery tool in comparison with viral technologies. We also discuss emerging SB-based hybrid vectors aimed at combining the attractive safety features of the transposon with effective viral delivery. The success of the SB-based technology can be fundamentally attributed to being able to insert fairly randomly into genomic regions that allow stable long-term expression of the delivered transgene cassette. SB has emerged as an efficient and economical toolkit for safe and efficient gene delivery for medical applications.

Engineering cell-based therapies to interface robustly with host physiology

Engineered cell-based therapies comprise a rapidly growing clinical technology for treating disease by leveraging the natural capabilities of cells, including migration, information transduction, and biosynthesis and secretion. There now exists a substantial portfolio of intracellular and extracellular sensors that enable bioengineers to program cells to execute defined responses to specific changes in state or environmental cues. As our capability to construct more sophisticated cellular programs increases, assessing and improving the degree to which cell-based therapies perform as desired in vivo will become an increasingly important consideration and opportunity for technological advancement. In this review, we seek to describe both current capabilities and potential needs for building cell-based therapies that interface with host physiology in a manner that is robust - a phrase we use in this context to describe the achievement of therapeutic efficacy across a range of patients and implementations. We first review the portfolio of sensors and outputs currently available for use in cell-based therapies by highlighting key advancements and current gaps. Then, we propose a conceptual framework for evaluating and pursuing robust clinical performance of engineered cell-based therapies.

Translating Science into Survival: Report on the Inaugural International Cancer Immunotherapy Conference

The inaugural International Cancer Immunotherapy Conference, cohosted by the Cancer Research Institute (CRI), the American Association for Cancer Research (AACR), the Association for Cancer Immunotherapy (CIMT), and the European Academy of Tumor Immunology (EATI), was held in New York City on September 16–19, 2015. The conference brought together nearly 1,400 scientists, clinicians, regulators, patient advocates, and other stakeholders to discuss the latest scientific developments in cancer immunology and immunotherapy, as well as the regulatory hurdles facing new drug development. This conference report summarizes the main themes that emerged during the 4-day meeting.

Engineered T cells: the promise and challenges of cancer immunotherapy

The immune system evolved to distinguish non-self from self to protect the organism. As cancer is derived from our own cells, immune responses to dysregulated cell growth present a unique challenge. This is compounded by mechanisms of immune evasion and immunosuppression that develop in the tumour microenvironment. The modern genetic toolbox enables the adoptive transfer of engineered T cells to create enhanced anticancer immune functions where natural cancer-specific immune responses have failed. Genetically engineered T cells, so-called 'living drugs', represent a new paradigm in anticancer therapy. Recent clinical trials using T cells engineered to express chimeric antigen receptors (CARs) or engineered T cell receptors (TCRs) have produced stunning results in patients with relapsed or refractory haematological malignancies. In this Review we describe some of the most recent and promising advances in engineered T cell therapy with a particular emphasis on what the next generation of T cell therapy is likely to entail.