Rapid Transduction and Expansion of Transduced T Cells with Maintenance of Central Memory Populations

CAR-NK Cell Therapy: A Transformative Approach to Overcoming Oncological Challenges

The use of chimeric antigen receptor (CAR) in natural killer (NK) cells for cancer therapy is gaining momentum, marking a significant shift in cancer treatment. This review aims to explore the potential of CAR-NK cell therapy in cancer immunotherapy, providing a fresh perspective. It discusses the innovative approaches in CAR-NK cell design and engineering, particularly targeting refractory or recurrent cancers. By comparing CAR-NK cells with traditional therapies, the review highlights their unique ability to tackle tumor heterogeneity and immune system suppression. Additionally, it explains how novel cytokines and receptors can enhance CAR-NK cell efficacy, specificity, and functionality. This review underscores the advantages of CAR-NK cells, including reduced toxicity, lower cost, and broader accessibility compared to CAR-T cells, along with their potential in treating both blood cancers and solid tumors.

DMPK perspective on quantitative model analysis for chimeric antigen receptor cell therapy: Advances and challenges

Chimeric antigen receptor (CAR) cells are genetically engineered immune cells that specifically target tumor-associated antigens and have revolutionized cancer treatment, particularly in hematological malignancies, with ongoing investigations into their potential applications in solid tumors. This review provides a comprehensive overview of the current status and challenges in drug metabolism and pharmacokinetics (DMPK) for CAR cell therapy, specifically emphasizing on quantitative modeling and simulation (M&S). Furthermore, the recent advances in quantitative model analysis have been reviewed, ranging from clinical data characterization to mechanism-based modeling that connects in vitro and in vivo nonclinical and clinical study data. Additionally, the future perspectives and areas for improvement in CAR cell therapy translation have been reviewed. This includes using formulation quality considerations, characterization of appropriate animal models, refinement of in vitro models for bottom-up approaches, and enhancement of quantitative bioanalytical methodology. Addressing these challenges within a DMPK framework is pivotal in facilitating the translation of CAR cell therapy, ultimately enhancing the patients' lives through efficient CAR cell therapies.

Automated production of gene-modified chimeric antigen receptor T cells using the Cocoon Platform

Autologous cell-based therapeutics have gained increasing attention in recent years because of their efficacy at treating diseases with limited therapeutic options. Chimeric antigen receptor (CAR) T-cell therapy has demonstrated clinical success in hematologic oncology indications, providing critically ill patients with a potentially curative therapy. Although engineered cell therapies such as CAR T cells provide new options for patients with unmet needs, the high cost and complexity of manufacturing may hinder clinical and commercial translation. The Cocoon Platform (Lonza, Basel, Switzerland) addresses many challenges, such as high labor demand, process consistency, contamination risks and scalability, by enabling efficient, functionally closed and automated production, whether at clinical or commercial scale. This platform is customizable and easy to use and requires minimal operator interaction, thereby decreasing process variability. We present two processes that demonstrate the Cocoon Platform's capabilities. We employed different T-cell activation methods-OKT3 and CD3/CD28 Dynabeads (Thermo Fisher Scientific, Waltham, MA, USA)-to generate final cellular products that meet the critical quality attributes of a clinical autologous CAR T-cell product. This study demonstrates a manufacturing solution for addressing challenges with manual methods of production and facilitating the scale-up of autologous cell therapy.

Generation of functionally distinct T-cell populations by altering the viscoelasticity of their extracellular matrix

The efficacy of adoptive T-cell therapies largely depends on the generation of T-cell populations that provide rapid effector function and long-term protective immunity. Yet it is becoming clearer that the phenotypes and functions of T cells are inherently linked to their localization in tissues. Here we show that functionally distinct T-cell populations can be generated from T cells that received the same stimulation by altering the viscoelasticity of their surrounding extracellular matrix (ECM). By using a model ECM based on a norbornene-modified collagen type I whose viscoelasticity can be adjusted independently from its bulk stiffness by varying the degree of covalent crosslinking via a bioorthogonal click reaction with tetrazine moieties, we show that ECM viscoelasticity regulates T-cell phenotype and function via the activator-protein-1 signalling pathway, a critical regulator of T-cell activation and fate. Our observations are consistent with the tissue-dependent gene-expression profiles of T cells isolated from mechanically distinct tissues from patients with cancer or fibrosis, and suggest that matrix viscoelasticity could be leveraged when generating T-cell products for therapeutic applications.

Recent advancement in targeted therapy and role of emerging technologies to treat cancer

Cancer is a complex disease that causes abnormal cell growth and spread. DNA mutations, chemical or environmental exposure, viral infections, chronic inflammation, hormone abnormalities, etc., are underlying factors that can cause cancer. Drug resistance and toxicity complicate cancer treatment. Additionally, the variability of cancer makes it difficult to establish universal treatment guidelines. Next-generation sequencing has made genetic testing inexpensive. This uncovers genetic mutations that can be treated with specialty drugs. AI (artificial intelligence), machine learning, biopsy, next-generation sequencing, and digital pathology provide personalized cancer treatment. This allows for patient-specific biological targets and cancer treatment. Monoclonal antibodies, CAR-T, and cancer vaccines are promising cancer treatments. Recent trial data incorporating these therapies have shown superiority in clinical outcomes and drug tolerability over conventional chemotherapies. Combinations of these therapies with new technology can change cancer treatment and help many. This review discusses the development and challenges of targeted therapies like monoclonal antibodies (mAbs), bispecific antibodies (BsAbs), bispecific T cell engagers (BiTEs), dual variable domain (DVD) antibodies, CAR-T therapy, cancer vaccines, oncolytic viruses, lipid nanoparticle-based mRNA cancer vaccines, and their clinical outcomes in various cancers. We will also study how artificial intelligence and machine learning help find new cancer treatment targets.

Serum-free lentiviral vector production is compatible with medium-resident nuclease activity arising from adherent HEK293T host cells engineered with a nuclease-encoding transgene

At present lentiviral vector production for cell and gene therapy commonly involves transient plasmid transfection of mammalian cells cultivated in serum-containing media and addition of exogenous nuclease to reduce host cell and plasmid DNA impurities. Switching from serum-containing media to chemically-defined, serum free media, and minimising the number of process additions, are both increasingly regarded as necessary steps for simplifying and potentially automating lentiviral vector bioprocessing in future. Here we adapted human embryonic kidney 293T (HEK293T) cells to grow in serum-free media and also modified these cells with transgenes designed to encode a secreted nuclease activity. Stable transfection of HEK293T cells with transgenes encoding the Staphylococcus aureus nuclease B (NucB) open reading frame with either its native secretion signal peptide, the murine Igκ chain leader sequence or a novel viral transport fusion protein, all resulted in qualitatively detectable nuclease activity in serum-free media. Serum-free transient transfection of human embryonic kidney HEK293T cells stably harbouring the transgene for NucB with its native secretion signal produced active lentivirus in the presence of medium-resident nuclease activity. This lentivirus material was able to transduce the AGF-T immortal T cell line with a green fluorescent protein reporter payload at a level of 2.05 × 10⁵ TU/mL (±3.34 × 10⁴ TU/mL). Sufficient nuclease activity was present in 10 μL of this unconcentrated lentivirus material to degrade 1.5 μg DNA within 2 h at 37 °C, without agitation - conditions compatible with lentivirus production. These observations demonstrate that lentiviral vector production, by transient transfection, is compatible with host cells harbouring a nuclease transgene and evidencing nuclease activity in their surrounding growth media. This work provides a solid basis for future investigations, beyond the scope of this present study, in which commercial and academic groups can apply this approach to therapeutic payloads and potentially omit exogenous nuclease bioprocess additions.

Assessment of anti-CD20 antibody pre-treatment for augmentation of CAR-T cell therapy in SIV-infected rhesus macaques

During chronic HIV and SIV infections, the majority of viral replication occurs within lymphoid follicles. In a pilot study, infusion of SIV-specific CD4-MBL-CAR-T cells expressing the follicular homing receptor, CXCR5, led to follicular localization of the cells and a reduction in SIV viral loads in rhesus macaques. However, the CAR-T cells failed to persist. We hypothesized that temporary disruption of follicles would create space for CAR-T cell engraftment and lead to increased abundance and persistence of CAR-T cells. In this study we treated SIV-infected rhesus macaques with CAR-T cells and preconditioned one set with anti-CD20 antibody to disrupt the follicles. We evaluated CAR-T cell abundance and persistence in four groups of SIVmac239-infected and ART-suppressed animals: untreated, CAR-T cell treated, CD20 depleted, and CD20 depleted/CAR-T cell treated. In the depletion study, anti-CD20 was infused one week prior to CAR-T infusion and cessation of ART. Anti-CD20 antibody treatment led to temporary depletion of CD20+ cells in blood and partial depletion in lymph nodes. In this dose escalation study, there was no impact of CAR-T cell infusion on SIV viral load. However, in both the depleted and non-depleted animals, CAR-T cells accumulated in and around lymphoid follicles and were Ki67+. CAR-T cells increased in number in follicles from 2 to 6 days post-treatment, with a median 15.2-fold increase in follicular CAR-T cell numbers in depleted/CAR-T treated animals compared to an 8.1-fold increase in non-depleted CAR-T treated animals. The increase in CAR T cells in depleted animals was associated with a prolonged elevation of serum IL-6 levels and a rapid loss of detectable CAR-T cells. Taken together, these data suggest that CAR-T cells likely expanded to a greater extent in depleted/CAR-T cell treated animals. Further studies are needed to elucidate mechanisms mediating the rapid loss of CAR-T cells and to evaluate strategies to improve engraftment and persistence of HIV-specific CAR-T cells. The potential for an inflammatory cytokine response appears to be enhanced with anti-CD20 antibody treatment and future studies may require CRS control strategies. These studies provide important insights into cellular immunotherapy and suggest future studies for improved outcomes.

Enhancing CAR-T cell functionality in a patient-specific manner

Patient responses to autologous CD19 chimeric antigen receptor (CAR) T-cell therapies are limited by insufficient and inconsistent cellular functionality. Here, we show that controlling the precise level of stimulation during T-cell activation to accommodate individual differences in the donor cells will dictate the functional attributes of CAR-T cell products. The functionality of CAR-T cell products, consisting of a diverse set of blood samples derived from healthy donors, acute lymphoblastic leukemia (ALL), and chronic lymphocytic lymphoma (CLL) patient samples, representing a range of patient health status, is tested upon culturing on artificial antigen-presenting cell scaffolds to deliver T-cell stimulatory ligands (anti-CD3/anti-CD28) at highly defined densities. A clear relationship is observed between the dose of stimulation, the phenotype of the T-cell blood sample prior to T-cell activation, and the functionality of the resulting CAR-T cell products. We present a model, based on this dataset, that predicts the precise stimulation needed to manufacture a desired CAR-T cell product, given the input T-cell attributes in the initial blood sample. These findings demonstrate a simple approach to enhance CAR-T functionality by personalizing the level of stimulation during T-cell activation to enable flexible manufacturing of more consistent and potent CAR-T cells.

Development of an anti-CAR antibody response in SIV-infected rhesus macaques treated with CD4-MBL CAR/CXCR5 T cells

T cells expressing a simian immunodeficiency (SIV)-specific chimeric antigen receptor (CAR) and the follicular homing molecule, CXCR5, were infused into antiretroviral therapy (ART) suppressed, SIV-infected rhesus macaques to assess their ability to localize to the lymphoid follicle and control the virus upon ART interruption. While the cells showed evidence of functionality, they failed to persist in the animals beyond 28 days. Development of anti-CAR antibodies could be responsible for the lack of persistence. Potential antigenic sites on the anti-SIV CAR used in these studies included domains 1 and 2 of CD4, the carbohydrate recognition domain (CRD) of mannose-binding lectin (MBL), and an extracellular domain of the costimulatory molecule, CD28, along with short linker sequences. Using a flow cytometry based assay and target cells expressing the CAR/CXCR5 construct, we examined the serum of the CD4-MBL CAR/CXCR5-T cell treated animals to determine that the animals had developed an anti-CAR antibody response after infusion. Binding sites for the anti-CAR antibodies were identified by using alternative CARs transduced into target cells and by preincubation of the target cells with a CD4 blocking antibody. All of the treated animals developed antibodies in their serum that bound to CD4-MBL CAR/CXCR5 T cells and the majority were capable of inducing an ADCC response. The CD4 antibody-blocking assay suggests that the dominant immunogenic components of this CAR are the CD4 domains with a possible additional site of the CD28 domain with its linker. This study shows that an anti-drug antibody (ADA) response can occur even when using self-proteins, likely due to novel epitopes created by abridged self-proteins and/or the self-domain of the CAR connection to a small non-self linker. While in our study, there was no statistically significant correlation between the ADA response and the persistence of the CD4-MBL CAR/CXCR5-T cells in rhesus macaques, these findings suggest that the development of an ADA response could impact the long-term persistence of self-based CAR immunotherapies.

Protocol to assess cell-intrinsic regulatory mechanisms using an ex vivo murine T cell polarization and co-culture system

This protocol describes an ex vivo cell culture system for simultaneously generating a mixture of CD4⁺ T helper lineages, including T helper 17 (Th17), RORγt⁺ Treg, and conventional Treg (cTreg), in proportions representative of those found in mucosal tissues in vivo. When combined with a co-culture approach, this system allows a more rapid assessment of a candidate molecule's T cell-intrinsic and -extrinsic functions over the traditional bone marrow chimera and co-transfer approaches. For complete details on the use and execution of this protocol, please refer to Ma et al. (2022).

Influence of Culture Conditions on Ex Vivo Expansion of T Lymphocytes and Their Function for Therapy: Current Insights and Open Questions

Ex vivo expansion of T lymphocytes is a central process in the generation of cellular therapies targeted at tumors and other disease-relevant structures, which currently cannot be reached by established pharmaceuticals. The influence of culture conditions on T cell functions is, however, incompletely understood. In clinical applications of ex vivo expanded T cells, so far, a relatively classical standard cell culture methodology has been established. The expanded cells have been characterized in both preclinical models and clinical studies mainly using a therapeutic endpoint, for example antitumor response and cytotoxic function against cellular targets, whereas the influence of manipulations of T cells ex vivo including transduction and culture expansion has been studied to a much lesser detail, or in many contexts remains unknown. This includes the circulation behavior of expanded T cells after intravenous application, their intracellular metabolism and signal transduction, and their cytoskeletal (re)organization or their adhesion, migration, and subsequent intra-tissue differentiation. This review aims to provide an overview of established T cell expansion methodologies and address unanswered questions relating in vivo interaction of ex vivo expanded T cells for cellular therapy.

CAR/CXCR5-T cell immunotherapy is safe and potentially efficacious in promoting sustained remission of SIV infection

During chronic human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) infection prior to AIDS progression, the vast majority of viral replication is concentrated within B cell follicles of secondary lymphoid tissues. We investigated whether infusion of T cells expressing an SIV-specific chimeric antigen receptor (CAR) and the follicular homing receptor, CXCR5, could successfully kill viral-RNA+ cells in targeted lymphoid follicles in SIV-infected rhesus macaques. In this study, CD4 and CD8 T cells from rhesus macaques were genetically modified to express antiviral CAR and CXCR5 moieties (generating CAR/CXCR5-T cells) and autologously infused into a chronically infected animal. At 2 days post-treatment, the CAR/CXCR5-T cells were located primarily in spleen and lymph nodes both inside and outside of lymphoid follicles. Few CAR/CXCR5-T cells were detected in the ileum, rectum, and lung, and no cells were detected in the bone marrow, liver, or brain. Within follicles, CAR/CXCR5-T cells were found in direct contact with SIV-viral RNA+ cells. We next infused CAR/CXCR5-T cells into ART-suppressed SIV-infected rhesus macaques, in which the animals were released from ART at the time of infusion. These CAR/CXCR5-T cells replicated in vivo within both the extrafollicular and follicular regions of lymph nodes and accumulated within lymphoid follicles. CAR/CXR5-T cell concentrations in follicles peaked during the first week post-infusion but declined to undetectable levels after 2 to 4 weeks. Overall, CAR/CXCR5-T cell-treated animals maintained lower viral loads and follicular viral RNA levels than untreated control animals, and no outstanding adverse reactions were noted. These findings indicate that CAR/CXCR5-T cell treatment is safe and holds promise as a future treatment for the durable remission of HIV.

Scalable Manufacturing of CAR T cells for Cancer Immunotherapy

As of April 2021, there are five commercially available chimeric antigen receptor (CAR) T cell therapies for hematological malignancies. With the current transition of CAR T cell manufacturing from academia to industry, there is a shift toward Good Manufacturing Practice (GMP)-compliant closed and automated systems to ensure reproducibility and to meet the increased demand for cancer patients. In this review we describe current CAR T cells clinical manufacturing models and discuss emerging technological advances that embrace scaling and production optimization. We summarize measures being used to shorten CAR T-cell manufacturing times and highlight regulatory challenges to scaling production for clinical use.

Statement of Significance ∣

As the demand for CAR T cell cancer therapy increases, several closed and automated production platforms are being deployed, and others are in development.This review provides a critical appraisal of these technologies that can be leveraged to scale and optimize the production of next generation CAR T cells.

Lymphocyte expansion in bioreactors: upgrading adoptive cell therapy

Bioreactors are essential tools for the development of efficient and high-quality cell therapy products. However, their application is far from full potential, holding several challenges when reconciling the complex biology of the cells to be expanded with the need for a manufacturing process that is able to control cell growth and functionality towards therapy affordability and opportunity. In this review, we discuss and compare current bioreactor technologies by performing a systematic analysis of the published data on automated lymphocyte expansion for adoptive cell therapy. We propose a set of requirements for bioreactor design and identify trends on the applicability of these technologies, highlighting the specific challenges and major advancements for each one of the current approaches of expansion along with the opportunities that lie in process intensification. We conclude on the necessity to develop targeted solutions specially tailored for the specific stimulation, supplementation and micro-environmental needs of lymphocytes’ cultures, and the benefit of applying knowledge-based tools for process control and predictability.

Nonviral gene delivery to T cells with Lipofectamine LTX

Retroviral gene delivery is widely used in T cell therapies for hematological cancers. However, viral vectors are expensive to manufacture, integrate genes in semirandom patterns, and their transduction efficiency varies between patients. In this study, several nonviral gene delivery vehicles, promoters, and additional variables were compared to optimize nonviral transgene delivery and expression in both Jurkat and primary T cells. Transfection of Jurkat cells was maximized to a high efficiency (63.0% ± 10.9% EGFP⁺  cells) by transfecting cells with Lipofectamine LTX in X-VIVO 15 media. However, the same method yielded a much lower transfection efficiency in primary T cells (8.1% ± 0.8% EGFP⁺ ). Subsequent confocal microscopy revealed that a majority of the lipoplexes did not enter the primary T cells, which might be due to relatively low expression levels of heparan sulfate proteoglycans detected via messenger RNA-sequencing. Pyrin and HIN (PYHIN) DNA sensors (e.g., AIM2 and IFI16) that can induce apoptosis or repress transcription after binding cytoplasmic DNA were also detected at high levels in primary T cells. Therefore, transfection of primary T cells appears to be limited at the level of cellular uptake or DNA sensing in the cytoplasm. Both of these factors should be considered in the development of future viral and nonviral T cell gene delivery methods.

Cell-Based Therapy Manufacturing in Stirred Suspension Bioreactor: Thoughts for cGMP Compliance

Cell-based therapy (CBT) is attracting much attention to treat incurable diseases. In recent years, several clinical trials have been conducted using human pluripotent stem cells (hPSCs), and other potential therapeutic cells. Various private- and government-funded organizations are investing in finding permanent cures for diseases that are difficult or expensive to treat over a lifespan, such as age-related macular degeneration, Parkinson’s disease, or diabetes, etc. Clinical-grade cell manufacturing requiring current good manufacturing practices (cGMP) has therefore become an important issue to make safe and effective CBT products. Current cell production practices are adopted from conventional antibody or protein production in the pharmaceutical industry, wherein cells are used as a vector to produce the desired products. With CBT, however, the “cells are the final products” and sensitive to physico- chemical parameters and storage conditions anywhere between isolation and patient administration. In addition, the manufacturing of cellular products involves multi-stage processing, including cell isolation, genetic modification, PSC derivation, expansion, differentiation, purification, characterization, cryopreservation, etc. Posing a high risk of product contamination, these can be time- and cost- prohibitive due to maintenance of cGMP. The growing demand of CBT needs integrated manufacturing systems that can provide a more simple and cost-effective platform. Here, we discuss the current methods and limitations of CBT, based upon experience with biologics production. We review current cell manufacturing integration, automation and provide an overview of some important considerations and best cGMP practices. Finally, we propose how multi-stage cell processing can be integrated into a single bioreactor, in order to develop streamlined cGMP-compliant cell processing systems.

Optimization of electroporation and other non-viral gene delivery strategies for T cells

CAR-T therapy is a particularly effective treatment for some types of cancer that uses retroviruses to deliver the gene for a chimeric antigen receptor (CAR) to a patient's T cells ex vivo. The CAR enables the T cells to bind and eradicate cells with a specific surface marker (e.g., CD19⁺ B cells) after they are transfused back into the patient. This treatment was proven to be particularly effective in treating non-Hodgkin's lymphoma (NHL) and acute lymphoblastic leukemia (ALL), but the current CAR-T cell manufacturing process has a few significant drawbacks. For example, while lentiviral and gammaretroviral transduction are both relatively effective, the process of producing viral vectors is time-consuming and costly. Additionally, patients must undergo follow up appointments for several years to monitor them for any unanticipated side effects associated with the virus. Therefore, several studies have endeavored to find alternative non-viral gene delivery methods that are less expensive, more precise, simple, and safe. This review focuses on the current state of the most promising non-viral gene delivery techniques, including electroporation and transfection with cationic polymers or lipids.

Bioprocess considerations for T-cell therapy: Investigating the impact of agitation, dissolved oxygen, and pH on T-cell expansion and differentiation

Adoptive T-cell therapy (ACT) has emerged as a promising new way to treat systemic cancers such as acute lymphoblastic leukemia. However, the robustness and reproducibility of the manufacturing process remains a challenge. Here, a single-use 24-well microbioreactor (micro-Matrix) was assessed for its use as a high-throughput screening tool to investigate the effect and the interaction of different shaking speeds, dissolved oxygen (DO), and pH levels on the growth and differentiation of primary T cells in a perfusion-mimic process. The full factorial design allowed for the generation of predictive models, which were used to find optimal culture conditions. Agitation was shown to play a fundamental role in the proliferation of T cells. A shaking speed of 200 rpm drastically improved the final viable cell concentration (VCC), while the viability was maintained above 90% throughout the cultivation. VCCs reached a maximum of 9.22 × 10⁶ cells/ml. The distribution of CD8+ central memory T cells (T_CM ), was found to be largely unaffected by the shaking speed. A clear interaction between pH and DO (p < .001) was established for the cell growth and the optimal culture conditions were identified for a combination of 200 rpm, 25% DO, and pH of 7.4. The combination of microbioreactor technology and Design of Experiment methodology provides a powerful tool to rapidly gain an understanding of the design space of the T-cell manufacturing process.

Overview of anti-BCMA CAR-T immunotherapy for multiple myeloma and relapsed/refractory multiple myeloma

Multiple myeloma (MM) is a haematological malignancy caused by malignant proliferation of plasma cells in bone marrow. In recent years, MM patients are commonly treated with chemotherapy, autologous stem cell transplantation, protease inhibitors, immunomodulatory drugs and monoclonal antibodies, however most patients eventually relapse. Therefore, more effective therapies are highly needed. Anti-BCMA CAR-T therapy, a novel and efficacious method for treating MM and relapsed/refractory multiple myeloma (RRMM), has been designed and applied in clinics. The CAR-T can specifically recognize the targeted molecule B cell maturation antigen (BCMA) and kill MM cells expressing BCMA and several clinical trials have revealed high response rates in the therapy. Herein, we summarize the developments, the current design and clinical trials, the side effects of anti-BCMA CAR-T therapy and comparison of it with other CAR-T therapies.

A Bird's-Eye View of Cell Sources for Cell-Based Therapies in Blood Cancers

: Hematological malignancies comprise over a hundred different types of cancers and account for around 6.5% of all cancers. Despite the significant improvements in diagnosis and treatment, many of those cancers remain incurable. In recent years, cancer cell-based therapy has become a promising approach to treat those incurable hematological malignancies with striking results in different clinical trials. The most investigated, and the one that has advanced the most, is the cell-based therapy with T lymphocytes modified with chimeric antigen receptors. Those promising initial results prepared the ground to explore other cell-based therapies to treat patients with blood cancer. In this review, we want to provide an overview of the different types of cell-based therapies in blood cancer, describing them according to the cell source.