The antigen-binding moiety in the driver's seat of CARs

CAR T cells in lung cancer: Targeting tumor-associated antigens to revolutionize immunotherapy

Tumor-targeted T cells engineered for targeting and killing tumor cells have revolutionized cancer treatment, specifically in hematologic malignancies, through chimeric antigen receptor (CAR) T cell therapy. However, the migration of this success to lung cancer is challenging due to the tumor microenvironment (TME), antigen heterogeneity, and limitations of T cell infiltration. This review aims to evaluate current strategies addressing these barriers, focusing on the optimization of tumor-associated antigen (TAA) targeting, such as epidermal growth factor receptor (EGFR), mucin-1 (MUC1), and mesothelin (MSLN), which are frequently overexpressed in lung cancer and offer promising targets for CAR T-cell therapy. In this review, we discuss recent progress in CAR T cell engineering, applying enhanced costimulatory molecules, cytokine-secreting CAR T cells, and engineered modifications to improve T cell resilience in immunosuppressive environments. Additionally, this review also evaluates combination therapies of immune checkpoint inhibitors and recently published clinical trials on lung cancer with CAR T cells. We offer insights into the way to optimize CAR T cell therapy for lung cancer by analyzing antigen selection, immune evasion, and the strategies to enhance T cell persistence and tumor infiltration.

Discovery and preclinical development of a SdAb-based CAR-T technology for targeting CD33 in AML

Chimeric antigen receptor T cell (CAR-T) therapies have revolutionized cancer immunotherapy. Traditional single-chain variable fragments (ScFvs) used as CAR recognition moieties face challenges such as high tonic signaling, compromised binding epitopes, and suboptimal affinity. Single-domain antibodies (SdAbs) offer an attractive alternative due to their smaller size, stability, and reduced immunogenicity. In this work, we developed an SdAb-CAR-T cell discovery platform integrating generation, characterization, and selection of SdAbs based on various properties. This approach was demonstrated by developing CAR-T cells with SdAbs against CD33, a target for acute myeloid leukemia (AML). We identified diverse SdAbs against CD33, with affinities ranging from 3.9-115 nM, and characterized their binding kinetics and epitope recognition. Using SdAb-based second-generation CARs, we assessed tonic signaling, T cell phenotypes, cytotoxicity and cytokine release in vitro, resulting in reduced tonic signaling and increased cytokine production. In vivo, SdAb-based CAR-T cells exhibited enhanced efficacy at lower doses, in a xenograft AML mouse model, demonstrating advantages over ScFv-based CD33 CAR-T cells.

Advances in CAR T cell therapy: antigen selection, modifications, and current trials for solid tumors

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of hematologic malignancies, achieving remarkable clinical success with FDA-approved therapies targeting CD19 and BCMA. However, the extension of these successes to solid tumors remains limited due to several intrinsic challenges, including antigen heterogeneity and immunosuppressive tumor microenvironments. In this review, we provide a comprehensive overview of recent advances in CAR T cell therapy aimed at overcoming these obstacles. We discuss the importance of antigen identification by emphasizing the identification of tumor-specific and tumor-associated antigens and the development of CAR T therapies targeting these antigens. Furthermore, we highlight key structural innovations, including cytokine-armored CARs, protease-regulated CARs, and CARs engineered with chemokine receptors, to enhance tumor infiltration and activity within the immunosuppressive microenvironment. Additionally, novel manufacturing approaches, such as the Sleeping Beauty transposon system, mRNA-based CAR transfection, and in vivo CAR T cell production, are discussed as scalable solution to improve the accessibility of CAR T cell therapies. Finally, we address critical therapeutic limitations, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and suboptimal persistence of CAR T cells. An examination of emerging strategies for countering these limitations reveals that CRISPR-Cas9-mediated genetic modifications and combination therapies utilizing checkpoint inhibitors can improve CAR T cell functionality and durability. By integrating insights from preclinical models, clinical trials, and innovative engineering approaches, this review addresses advances in CAR T cell therapies and their performance in solid tumors.

Cancer vaccines: an update on recent achievements and prospects for cancer therapy

Decades of basic and translational research have led to a momentum shift in dissecting the relationship between immune cells and cancer. This culminated in the emergence of breakthrough immunotherapies that paved the way for oncologists to manage certain hard-to-treat cancers. The application of high-throughput techniques of genomics, transcriptomics, and proteomics was conclusive in making and expediting the manufacturing process of cancer vaccines. Using the latest research technologies has also enabled scientists to interpret complex and multiomics data of the tumour mutanome, thus identifying new tumour-specific antigens to design new generations of cancer vaccines with high specificity and long-term efficacy. Furthermore, combinatorial regimens of cancer vaccines with immune checkpoint inhibitors have offered new therapeutic approaches and demonstrated impressive efficacy in cancer patients over the last few years. In the present review, we summarize the current state of cancer vaccines, including their potential therapeutic effects and the limitations that hinder their effectiveness. We highlight the current efforts to mitigate these limitations and highlight ongoing clinical trials. Finally, a special focus will be given to the latest milestones expected to transform the landscape of cancer therapy and nurture hope among cancer patients.

Modular (universal) CAR-T platforms in vivo: a comprehensive systematic review

Background

Modular (universal) CAR T-platforms were developed to combat the limitations of traditional CAR-T therapy, allowing for multiple targeting of tumor-associated antigens and the ability to control CAR-T cell activity. The modular CAR-T platform consists of a universal receptor (signaling module) that recognizes an adapter molecule on the soluble module, which is responsible for antigen recognition. Multiple platforms have been developed over the last 12 years, and some of them have entered the clinical trial phase. This systematic review seeks to evaluate the different parameters of modular CAR-T platforms performance in animal models.

Methods

A systematic search of literature in the PubMed database and in Google Scholar and BASE (Bielefeld Academic Search Engine) search engines was performed according to predefined eligibility criteria. All studies conducted on xenograft mouse models with any variant of modular CAR-T platforms were included. Forest plots were generated for visual presentation of the extracted quantitative findings (standardized mean difference (SMD) and median survival rate (MSR)).

Results

A total of 33 studies employing 15 different modular CAR-T platforms were included. The platforms varied in terms of CAR-T cells, soluble module doses, and their frequency of administration. The studies showed a reduction in tumor burden and in tumor volume compared to the combined negative group. In comparison with the positive control group, there was no significant change in tumor burden or volume. In all the included studies the experimental group had a higher survival probability compared to the combined negative group at the study endpoint, with no significant difference in survival rate compared to the positive control group.

Conclusion

The modular CAR-T platforms are generally effective and are a valuable addition to the arsenal of CAR therapy.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/ PROSPERO, identifier CRD42023443984.

Preclinical evaluation of antigen-sensitive B7-H3-targeting nanobody-based CAR-T cells in glioblastoma cautions for on-target, off-tumor toxicity

BACKGROUND

Glioblastoma is the most common lethal primary brain tumor, urging evaluation of new treatment options. Chimeric antigen receptor (CAR)-T cells targeting B7 homolog 3 (B7-H3) are promising because of the overexpression of B7-H3 on glioblastoma cells but not on healthy brain tissue. Nanobody-based (nano)CARs are gaining increasing attention as promising alternatives to classical single-chain variable fragment-based (scFv)CARs, because of their single-domain nature and low immunogenicity. Still, B7-H3 nanoCAR-T cells have not been extensively studied in glioblastoma.

METHODS

B7-H3 nanoCAR- and scFvCAR-T cells were developed and evaluated in human glioblastoma models. NanoCAR-T cells targeting an irrelevant antigen served as control. T cell activation, cytokine secretion and killing capacity were evaluated in vitro using ELISA, live cell imaging and flow cytometry. Antigen-specific killing was assessed by generating B7-H3 knock-out cells using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9-genome editing. The tumor tracing capacity of the B7-H3 nanobody was first evaluated in vivo using nuclear imaging. Then, the therapeutic potential of the nanoCAR-T cells was evaluated in a xenograft glioblastoma model.

RESULTS

We showed that B7-H3 nanoCAR-T cells were most efficient in lysing B7-H3pos glioblastoma cells in vitro. Lack of glioblastoma killing by control nanoCAR-T cells and lack of B7-H3neg glioblastoma killing by B7-H3 nanoCAR-T cells showed antigen-specificity. We showed in vivo tumor targeting capacity of the B7-H3 nanobody-used for the nanoCAR design-in nuclear imaging experiments. Evaluation of the nanoCAR-T cells in vivo showed tumor control in mice treated with B7-H3 nanoCAR-T cells in contrast to progressive disease in mice treated with control nanoCAR-T cells. However, we observed limiting toxicity in mice treated with B7-H3 nanoCAR-T cells and showed that the B7-H3 nanoCAR-T cells are activated even by low levels of mouse B7-H3 expression.

CONCLUSIONS

B7-H3 nanoCAR-T cells showed promise for glioblastoma therapy following in vitro characterization, but limiting in vivo toxicity was observed. Off-tumor recognition of healthy mouse tissue by the cross-reactive B7-H3 nanoCAR-T cells was identified as a potential cause for this toxicity, warranting caution when using highly sensitive nanoCAR-T cells, recognizing the low-level expression of B7-H3 on healthy tissue.

The future of cellular therapy for the treatment of renal cell carcinoma

INTRODUCTION

Systemic treatment options for renal cell carcinoma (RCC) have expanded considerably in recent years, and both tyrosine kinase inhibitors and immune checkpoint inhibitors, alone or in combination, have entered the clinical arena. Adoptive cell immunotherapies have recently revolutionized the treatment of cancer and hold the promise to further advance the treatment of RCC.

AREAS COVERED

In this review, we summarize the latest preclinical and clinical development in the field of adoptive cell immunotherapy for the treatment of RCC, focusing on lymphokine-activated killer (LAK) cells, cytokine-induced killer (CIK) cells, tumor-infiltrating T cells (TILs), TCR-engineered T cells, chimeric antigen receptor (CAR) T cells, and dendritic cell vaccination strategies. Perspectives on emerging cellular products including CAR NK cells, CAR macrophages, as well as γδ T cells are also included.

EXPERT OPINION

So far, areas of greater therapeutic success of adoptive cell therapies include the adjuvant administration of CIK cells and the transfer of anti-CD70 CAR T cells in patients with metastatic RCC. Bench to bedside and back research will be needed to overcome current limitations of adoptive cell therapies in RCC, primarily aiming at improving the safety of immune cell products, optimizing their antitumor activity and generating off-the-shelf products ready for clinical use.

Impact of scFv on Functionality and Safety of Third-Generation CD123 CAR T Cells

Chimeric antigen receptor (CAR) T cells express an extracellular domain consisting of a single-chain fragment variable (scFv) targeting a surface tumor-associated antigen. scFv selection should involve safety profiling with evaluation of the efficacy/toxicity balance, especially when the target antigen also is expressed on healthy cells. Here, to assess differences in terms of efficacy and on-target/off-tumor effects, we generated five different CARs targeting CD123 by substituting only the scFv. In in vitro models, T cells engineered to express three of these five CD123 CARs were effectively cytotoxic on leukemic cells without increasing lysis of monocytes or endothelial cells. Using the IncuCyte system, we confirmed the low cytotoxicity of CD123 CAR T cells on endothelial cells. Hematotoxicity evaluation using progenitor culture and CD34 cell lysis showed that two of the five CD123 CAR T cells were less cytotoxic on hematopoietic stem cells. Using a humanized mouse model, we confirmed that CD123- cells were not eliminated by the CD123 CAR T cells. Two CD123 CAR T cells reduced tumor infiltration and increased the overall survival of mice in three in vivo models of blastic plasmacytoid dendritic cell neoplasm. In an aggressive version of this model, bulk RNA sequencing analysis showed that these CD123 CAR T cells upregulated genes associated with cytotoxicity and activation/exhaustion a few days after the injection. Together, these results emphasize the importance of screening different scFvs for the development of CAR constructs to support selection of cells with the optimal risk-benefit ratio for clinical development.

Fueling CARs: metabolic strategies to enhance CAR T-cell therapy

CAR T cells are widely applied for relapsed hematological cancer patients. With six approved cell therapies, for Multiple Myeloma and other B-cell malignancies, new insights emerge. Profound evidence shows that patients who fail CAR T-cell therapy have, aside from antigen escape, a more glycolytic and weakened metabolism in their CAR T cells, accompanied by a short lifespan. Recent advances show that CAR T cells can be metabolically engineered towards oxidative phosphorylation, which increases their longevity via epigenetic and phenotypical changes. In this review we elucidate various strategies to rewire their metabolism, including the design of the CAR construct, co-stimulus choice, genetic modifications of metabolic genes, and pharmacological interventions. We discuss their potential to enhance CAR T-cell functioning and persistence through memory imprinting, thereby improving outcomes. Furthermore, we link the pharmacological treatments with their anti-cancer properties in hematological malignancies to ultimately suggest novel combination strategies.

Anti-Idiotypic VHHs and VHH-CAR-T Cells to Tackle Multiple Myeloma: Different Applications Call for Different Antigen-Binding Moieties

CAR-T cell therapy is at the forefront of next-generation multiple myeloma (MM) management, with two B-cell maturation antigen (BCMA)-targeted products recently approved. However, these products are incapable of breaking the infamous pattern of patient relapse. Two contributing factors are the use of BCMA as a target molecule and the artificial scFv format that is responsible for antigen recognition. Tackling both points of improvement in the present study, we used previously characterized VHHs that specifically target the idiotype of murine 5T33 MM cells. This idiotype represents one of the most promising yet challenging MM target antigens, as it is highly cancer- but also patient-specific. These VHHs were incorporated into VHH-based CAR modules, the format of which has advantages compared to scFv-based CARs. This allowed a side-by-side comparison of the influence of the targeting domain on T cell activation. Surprisingly, VHHs previously selected as lead compounds for targeted MM radiotherapy are not the best (CAR-) T cell activators. Moreover, the majority of the evaluated VHHs are incapable of inducing any T cell activation. As such, we highlight the importance of specific VHH selection, depending on its intended use, and thereby raise an important shortcoming of current common CAR development approaches.

Scrutiny of chimeric antigen receptor activation by the extracellular domain: experience with single domain antibodies targeting multiple myeloma cells highlights the need for case-by-case optimization

Introduction

Multiple myeloma (MM) remains incurable, despite the advent of chimeric antigen receptor (CAR)-T cell therapy. This unfulfilled potential can be attributed to two untackled issues: the lack of suitable CAR targets and formats. In relation to the former, the target should be highly expressed and reluctant to shedding; two characteristics that are attributed to the CS1-antigen. Furthermore, conventional CARs rely on scFvs for antigen recognition, yet this withholds disadvantages, mainly caused by the intrinsic instability of this format. VHHs have been proposed as valid scFv alternatives. We therefore intended to develop VHH-based CAR-T cells, targeting CS1, and to identify VHHs that induce optimal CAR-T cell activation together with the VHH parameters required to achieve this.

Methods

CS1-specific VHHs were generated, identified and fully characterized, in vitro and in vivo. Next, they were incorporated into second-generation CARs that only differ in their antigen-binding moiety. Reporter T-cell lines were lentivirally transduced with the different VHH-CARs and CAR-T cell activation kinetics were evaluated side-by-side. Affinity, cell-binding capacity, epitope location, in vivo behavior, binding distance, and orientation of the CAR-T:MM cell interaction pair were investigated as predictive parameters for CAR-T cell activation.

Results

Our data show that the VHHs affinity for its target antigen is relatively predictive for its in vivo tumor-tracing capacity, as tumor uptake generally decreased with decreasing affinity in an in vivo model of MM. This does not hold true for their CAR-T cell activation potential, as some intermediate affinity-binding VHHs proved surprisingly potent, while some higher affinity VHHs failed to induce equal levels of T-cell activation. This could not be attributed to cell-binding capacity, in vivo VHH behavior, epitope location, cell-to-cell distance or binding orientation. Hence, none of the investigated parameters proved to have significant predictive value for the extent of CAR-T cell activation.

Conclusions

We gained insight into the predictive parameters of VHHs in the CAR-context using a VHH library against CS1, a highly relevant MM antigen. As none of the studied VHH parameters had predictive value, defining VHHs for optimal CAR-T cell activation remains bound to serendipity. These findings highlight the importance of screening multiple candidates.

Immunotherapy for Ovarian Cancer: Disappointing or Promising?

Ovarian cancer, one of the deadliest malignancies, lacks effective treatment, despite advancements in surgical techniques and chemotherapy. Thus, new therapeutic approaches are imperative to improving treatment outcomes. Immunotherapy, which has demonstrated considerable success in managing various cancers, has already found its place in clinical practice. This review aims to provide an overview of ovarian tumor immunotherapy, including its basics, key strategies, and clinical research data supporting its potential. In particular, this discussion highlights promising strategies such as checkpoint inhibitors, vaccines, and pericyte transfer, both individually and in combination. However, the advancement of new immunotherapies necessitates large controlled randomized trials, which will undoubtedly shape the future of ovarian cancer treatment.

Promising Diagnostic and Therapeutic Approaches Based on VHHs for Cancer Management

The discovery of the distinctive structure of heavy chain-only antibodies in species belonging to the Camelidae family has elicited significant interest in their variable antigen binding domain (VHH) and gained attention for various applications, such as cancer diagnosis and treatment. This article presents an overview of the characteristics, advantages, and disadvantages of VHHs as compared to conventional antibodies, and their usage in diverse applications. The singular properties of VHHs are explained, and several strategies that can augment their utility are outlined. The preclinical studies illustrating the diagnostic and therapeutic efficacy of distinct VHHs in diverse formats against solid cancers are summarized, and an overview of the clinical trials assessing VHH-based agents in oncology is provided. These investigations demonstrate the enormous potential of VHHs for medical research and healthcare.

Solving the mystery of the FMC63-CD19 affinity

The majority of approved CAR T cell products are based on the FMC63-scFv directed against CD19. Surprisingly, although antigen binding affinity is a major determinant for CAR function, the affinity of the benchmark FMC63-scFv has not been unambiguously determined. That is, a wide range of affinities have been reported in literature, differing by more than 100-fold. Using a range of techniques, we demonstrate that suboptimal experimental designs can cause artefacts that lead to over- or underestimation of the affinity. To minimize these artefacts, we performed SPR with strictly monomeric and correctly folded soluble CD19, yielding an FMC63-scFv affinity of 2-6 nM. Together, apart from analyzing the FMC63-scFv affinity under optimized conditions, we also provide potential explanations for the wide range of published affinities. We expect that this study will be highly valuable for interpretations of CAR affinity-function relationships, as well as for the design of future CAR T cell generations.

Ligand-based, piggyBac-engineered CAR-T cells targeting EGFR are safe and effective against non-small cell lung cancers

Epidermal growth factor receptor (EGFR) is overexpressed in various cancers, including non-small cell lung cancer (NSCLC), and in some somatic cells at a limited level, rendering it an attractive antitumor target. In this study, we engineered chimeric antigen receptor (CAR)-T cells using the piggyBac transposon system, autologous artificial antigen-presenting cells, and natural ligands of EGFR. We showed that this approach yielded CAR-T cells with favorable phenotypes and CAR positivity. They exhibited potent antitumor activity against NSCLC both in vitro and in vivo. When administered to tumor-bearing mice and non-tumor-bearing cynomolgus macaques, they did not elicit toxicity despite their cross-reactivity to both murine and simian EGFRs. In total we tested three ligands and found that the CAR candidate with the highest affinity consistently displayed greater potency without adverse events. Taken together, our results demonstrate the feasibility and safety of targeting EGFR-expressing NSCLCs using ligand-based, piggyBac-engineered CAR-T cells. Our data also show that lowering the affinity of CAR molecules is not always beneficial.

Colorectal Cancer Immunotherapy: State of the Art and Future Directions

Cancer immunotherapy has become an indispensable mode of treatment for a multitude of solid tumor cancers. Colorectal cancer (CRC) has been one of the many cancer types to benefit from immunotherapy, especially in advanced disease where standard treatment fails to prevent recurrence or results in poor survival. The efficacy of immunotherapy in CRC has not been without challenge, as early clinical trials observed dismal responses in unselected CRC patients treated with checkpoint inhibitors. Many studies and clinical trials have since refined immunotherapies available for CRC, solidifying immunotherapy as a powerful asset for CRC treatment. This review article examines CRC immunotherapies, from their foundation, through emerging avenues for improvement, to future directions.

Best Practices and Considerations for Clinical Pharmacology and Pharmacometric Aspects for Optimal Development of CAR-T and TCR-T Cell Therapies: An Industry Perspective

With the promise of a potentially "single dose curative" paradigm, CAR-T cell therapies have brought a paradigm shift in the treatment and management of hematological malignancies. Both CAR-T and TCR-T cell therapies have also made great progress toward the successful treatment of solid tumor indications. The field is rapidly evolving with recent advancements including the clinical development of "off-the-shelf" allogeneic CAR-T therapies that can overcome the long and difficult "vein-to-vein" wait time seen with autologous CAR-T therapies. There are unique clinical pharmacology, pharmacometric, bioanalytical, and immunogenicity considerations and challenges in the development of these CAR-T and TCR-T cell therapies. Hence, to help accelerate the development of these life-saving therapies for the patients with cancer, experts in this field came together under the umbrella of International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) to form a joint working group between the Clinical Pharmacology Leadership Group (CPLG) and the Translational and ADME Sciences Leadership Group (TALG). In this white paper, we present the IQ consortium perspective on the best practices and considerations for clinical pharmacology and pharmacometric aspects toward the optimal development of CAR-T and TCR-T cell therapies.

From barriers to novel strategies: smarter CAR T therapy hits hard to tumors

Chimeric antigen receptor (CAR) T cell therapy for solid tumors shows promise, but several hurdles remain. Strategies to overcome barriers such as CAR T therapy-related toxicities (CTT), immunosuppression, and immune checkpoints through research and technology are needed to put the last nail to the coffin and offer hope for previously incurable malignancies. Herein we review current literature and infer novel strategies for the mitigation of CTT while impeding immune suppression, stromal barriers, tumor heterogeneity, on-target/off-tumor toxicities, and better transfection strategies with an emphasis on clinical research and prospects.

Current status and future expectations of nanobodies in oncology trials

INTRODUCTION

Monoclonal antibodies have revolutionized personalized medicine for cancer in recent decades. Despite their broad application in oncology, their large size and complexity may interfere with successful tumor targeting for certain applications of cancer diagnosis and therapy. Nanobodies have unique structural and pharmacological features compared to monoclonal antibodies and have successfully been used as complementary anti-cancer diagnostic and/or therapeutic tools.

AREAS COVERED

Here, an overview is given of the nanobody-based diagnostics and therapeutics that have been or are currently being tested in oncological clinical trials. Furthermore, preclinical developments, which are likely to be translated into the clinic in the near future, are highlighted.

EXPERT OPINION

Overall, the presented studies show the application potential of nanobodies in the field of oncology, making it likely that more nanobodies will be clinically approved in the upcoming future.

GPRC5D CAR T cells (OriCAR-017) in patients with relapsed or refractory multiple myeloma (POLARIS): a first-in-human, single-centre, single-arm, phase 1 trial

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy targeting B-cell maturation antigen (BCMA) has shown activity in treating relapsed or refractory multiple myeloma; however, relapse is still common, and new targets are needed. We aimed to assess the activity and safety profile of G protein-coupled receptor class C group 5 member D (GPRC5D)-targeted CAR T cells (OriCAR-017) in patients with relapsed or refractory multiple myeloma.

METHODS

POLARIS was a first-in-human, single-centre, single-arm, phase 1 trial of GPRC5D-targeted CAR T cells (OriCAR-017) done at the First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China. Eligible patients were adults aged 18-75 years with a diagnosis of relapsed or refractory multiple myeloma and an ECOG performance status of 0-2, had GPRC5D expression in bone marrow plasma cells greater than 20% or were positive for GPRC5D by immunohistochemistry, and had received at least three previous lines of treatment including proteasome inhibitors, immunomodulatory drugs, and chemotherapy. Patients were consecutively assigned to receive a single dose of intravenous OriCAR-017 at 1 × 10⁶ CAR T cells per kg, 3 × 10⁶ CAR T cells per kg, or 6 × 10⁶ CAR T cells per kg in the dose-escalation phase. In the expansion phase, patients received the recommended phase 2 dose. Recruitment to the expansion phase terminated early due to the COVID-19 pandemic on May 1, 2022. The primary endpoints were safety, the maximum tolerated dose and the recommended phase 2 dose. Safety and activity analyses included all patients who received OriCAR-017. This trial is registered with ClinicalTrials.gov, NCT05016778. This trial has been completed and is entering long-term follow-up.

FINDINGS

Between June 9, 2021, and Feb 28, 2022, we recruited 13 patients for inclusion into the study. One patient was excluded because of GPRC5D negativity and two patients discontinued after apheresis because of rapid progression. Nine patients were assigned to the dose escalation phase (three received 1 × 10⁶ CAR T cells per kg, three received 3 × 10⁶ CAR T cells per kg, and three received 6 × 10⁶ CAR T cells per kg). The maximum tolerated dose was not identified, because no dose-limiting toxic effects were observed. On the basis of safety and preliminary activity, the recommended phase 2 dose was set at 3 × 10⁶ CAR T cells per kg, which was received by one additional patient in the dose expansion phase. Five patients (50%) were female, five (50%) were male, and all were Chinese. Five patients (50%) were previously treated with BCMA-targeted CAR T-cell therapy. Median follow-up was 238 days (IQR 182-307). There were no serious adverse events and no treatment-related deaths. The most common grade 3 or worse adverse events were haematological, including neutropenia (ten [100%] of ten patients), thrombocytopenia (nine [90%]), leukopenia (nine [90%]), and anaemia (seven [70%]). All patients had cytokine release syndrome (nine [90%] grade 1 and one [10%] grade 2). No neurological toxic effects were reported. Ten (100%) of ten patients had an overall response, of whom six (60%) had a stringent complete response and four (40%) had very good partial response. Two patients discontinued due to disease progression (one GPRC5D-positive patient in the middle-dose group and one GPRC5D-negative patient in the low-dose group).

INTERPRETATION

The results of this study suggest that GPRC5D is an active target for immunotherapy in multiple myeloma. GPRC5D-targeted CAR T-cell therapy is a promising treatment modality for patients with relapsed or refractory multiple myeloma and deserves further testing.

FUNDING

OriCell Therapeutics.

Innovation in BCMA CAR-T therapy: Building beyond the Model T

Autologous chimeric antigen receptor T-cell (CAR-T) therapies targeting B-cell maturation antigen (BCMA) have revolutionized the field of multiple myeloma in the same way that the Ford Model T revolutionized the original CAR world a century ago. However, we are only beginning to understand how to improve the efficacy and usability of these cellular therapies. In this review, we explore three automotive analogies for innovation with BCMA CAR-T therapies: stronger engines, better mileage, and hassle-free delivery. Firstly, we can build stronger engines in terms of BCMA targeting: improved antigen binding, tools to modulate antigen density, and armoring to better reach the antigen itself. Secondly, we can improve "mileage" in terms of response durability through ex vivo CAR design and in vivo immune manipulation. Thirdly, we can implement hassle-free delivery through rapid manufacturing protocols and off-the-shelf products. Just as the Model T set a benchmark for car manufacturing over 100 years ago, idecabtagene vicleucel and ciltacabtagene autoleucel have now set the starting point for BCMA CAR-T therapy with their approvals. As with any emerging technology, whether automotive or cellular, the best in innovation and optimization is yet to come.

Targeting multiple myeloma with nanobody-based heavy chain antibodies, bispecific killer cell engagers, chimeric antigen receptors, and nanobody-displaying AAV vectors

Nanobodies are well suited for constructing biologics due to their high solubility. We generated nanobodies directed against CD38, a tumor marker that is overexpressed by multiple myeloma and other hematological malignancies. We then used these CD38-specific nanobodies to construct heavy chain antibodies, bispecific killer cell engagers (BiKEs), chimeric antigen receptor (CAR)-NK cells, and nanobody-displaying AAV vectors. Here we review the utility of these nanobody-based constructs to specifically and effectively target CD38-expressing myeloma cells. The promising results of our preclinical studies warrant further clinical studies to evaluate the potential of these CD38-specific nanobody-based constructs for treatment of multiple myeloma.

RNA in Cancer Immunotherapy: Unlocking the Potential of the Immune System

Recent advances in the manufacturing, modification, purification, and cellular delivery of ribonucleic acid (RNA) have enabled the development of RNA-based therapeutics for a broad array of applications. The approval of two SARS-CoV-2-targeting mRNA-based vaccines has highlighted the advances of this technology. Offering rapid and straightforward manufacturing, clinical safety, and versatility, this paves the way for RNA therapeutics to expand into cancer immunotherapy. Together with ongoing trials on RNA cancer vaccination and cellular therapy, RNA therapeutics could be introduced into clinical practice, possibly stewarding future personalized approaches. In the present review, we discuss recent advances in RNA-based immuno-oncology together with an update on ongoing clinical applications and their current challenges.

Ligand-based CAR-T cell: Different strategies to drive T cells in future new treatments

Chimeric antigen receptor (CAR)-based therapies are presented as innovative treatments for multiple malignancies. Despite their clinical success, there is scientific evidence of the limitations of these therapies mainly due to immunogenicity issues, toxicities associated with the infusion of the product, and relapses of the tumor. As a result, novel approaches are appearing aiming to solve and/or mitigate the harmful effects of CAR-T therapies. These include strategies based on the use of ligands as binding moieties or ligand-based CAR-T cells. Several proposals are currently under development, with some undergoing clinical trials to assess their potential benefits. In addition to these, therapies such as chimeric autoantibody receptor (CAAR), B-cell receptor antigen for reverse targeting (BAR), and even chimeric human leukocyte antigen (HLA) antibody receptor (CHAR) have emerged, benefiting from the advantages of antigenic ligands as antibody-binding motifs. This review focuses on the potential role that ligands can play in current and future antitumor treatments and in other types of diseases, such as autoimmune diseases or problems associated with transplantation.

Immunogenicity of CAR-T Cell Therapeutics: Evidence, Mechanism and Mitigation

Chimeric antigen receptor T cell (CAR-T) therapy demonstrated remarkable success in long-term remission of cancers and other autoimmune diseases. Currently, six products (Kymriah, Yescarta, Tecartus, Breyanzi, Abecma, and Carvykti) are approved by the US-FDA for treatment of a few hematological malignancies. All the six products are autologous CAR-T cell therapies, where delivery of CAR, which comprises of scFv (single-chain variable fragment) derived from monoclonal antibodies for tumor target antigen recognition is through a lentiviral vector. Although available CAR-T therapies yielded impressive response rates in a large number of patients in comparison to conventional treatment strategies, there are potential challenges in the field which limit their efficacy. One of the major challenges is the induction of humoral and/or cellular immune response in patients elicited due to scFv domain of CAR construct, which is of non-human origin in majority of the commercially available products. Generation of anti-CAR antibodies may lead to the clearance of the therapeutic CAR-T cells, increasing the likelihood of tumor relapse and lower the CAR-T cells efficacy upon reinfusion. These immune responses influence CAR-T cell expansion and persistence, that might affect the overall clinical response. In this review, we will discuss the impact of immunogenicity of the CAR transgene on treatment outcomes. Finally, this review will highlight the mitigation strategies to limit the immunogenic potential of CARs and improve the therapeutic outcome.

Emerging applications of nanobodies in cancer therapy

Cancer is a heterogeneous disease, requiring treatment tailored to the unique phenotype of the patient's tumor. Monoclonal antibodies (mAbs) and variants thereof have enabled targeted therapies to selectively target cancer cells. Cancer cell-specific mAbs have been used for image-guided surgery and targeted delivery of radionuclides or toxic agents, improving classical treatment strategies. Cancer cell-specific mAbs can further inhibit tumor cell growth or can stimulate immune-mediated destruction of cancer cells, a feature that has also been achieved through mAb-mediated manipulation of immune cells and pathways. Drawbacks of mAbs and their variants, together with the discovery of camelid heavy chain-only antibodies and the many advantageous features of their variable domains, referred to as V_HHs, single domain antibodies or nanobodies (Nbs), resulted in the exploration of Nbs as an alternative targeting moiety. We therefore review the state-of-the-art as well as novel exploitation strategies of Nbs for targeted cancer therapy.

Bibliometric Analysis of Chimeric Antigen Receptor-Based Immunotherapy in Cancers From 2001 to 2021

Background

Chimeric antigen receptor (CAR)-based immunotherapy has shown great potential for the treatment of both hematopoietic malignancies and solid tumors. Nevertheless, multiple obstacles still block the development of CAR-based immunotherapy in the clinical setting. In this study, we aimed to summarize the research landscape and highlight the front lines and trends of this field.

Methods

Literature published from 2001 to 2021 was searched in the Web of Science Core Collection database. Full records and cited references of all the documents were extracted and screened. Bibliometric analysis and visualization were conducted using CiteSpace, Microsoft Excel 2019, VOSviewer and R software.

Results

A total of 5981 articles and reviews were included. The publication and citation results exhibited increasing trends in the last 20 years. Frontiers in Immunology and Blood were the most productive and most co-cited journals, respectively. The United States was the country with the most productive organizations and publications in the comprehensive worldwide cooperation network, followed by China and Germany. June, C.H. published the most papers with the most citations, while Maude, S.L. ranked first among the co-cited authors. The hotspots in CAR-based therapy research were multiple myeloma, safety and toxicity, solid tumors, CAR-engineered immune cells beyond T cells, and gene editing.

Conclusion

CAR-based immunotherapy is a promising treatment for cancer patients, and there is an emerging movement toward using advanced gene modification technologies to overcome therapeutic challenges, especially in solid tumors, and to generate safer and more effective universal CAR-engineered cell products.

Reprogramming the tumor microenvironment by genome editing for precision cancer therapy

The tumor microenvironment (TME) is essential for immune escape by tumor cells. It plays essential roles in tumor development and metastasis. The clinical outcomes of tumors are often closely related to individual differences in the patient TME. Therefore, reprogramming TME cells and their intercellular communication is an attractive and promising strategy for cancer therapy. TME cells consist of immune and nonimmune cells. These cells need to be manipulated precisely and safely to improve cancer therapy. Furthermore, it is encouraging that this field has rapidly developed in recent years with the advent and development of gene editing technologies. In this review, we briefly introduce gene editing technologies and systematically summarize their applications in the TME for precision cancer therapy, including the reprogramming of TME cells and their intercellular communication. TME cell reprogramming can regulate cell differentiation, proliferation, and function. Moreover, reprogramming the intercellular communication of TME cells can optimize immune infiltration and the specific recognition of tumor cells by immune cells. Thus, gene editing will pave the way for further breakthroughs in precision cancer therapy.

T-cell subsets in the skin and their role in inflammatory skin disorders

T lymphocytes (T cells) are major players of the adaptive immune response. Naive T cells are primed in the presence of cytokines, leading to polarization into distinct T-cell subsets with specific functions. These subsets are classified based on their T-cell receptor profile, expression of transcription factors, surface cytokine and chemokine receptors, and their cytokine production, which together determine their specific function. This review provides an overview of the various T-cell subsets and their function in several inflammatory skin disorders ranging from allergic inflammation to skin tumors. Moreover, we highlight similarities of T-cell responses across different skin disorders, demonstrating the presence of similar and opposing functions for the different T-cell subsets. Finally, we discuss the effects of currently available and promising therapeutic approaches to harness T cells in inflammatory skin diseases for which efficacy next to unwanted side effects provide new insights into the pathophysiology of skin disorders.

Controlling Cell Trafficking: Addressing Failures in CAR T and NK Cell Therapy of Solid Tumours

The precision guiding of endogenous or adoptively transferred lymphocytes to the solid tumour mass is obligatory for optimal anti-tumour effects and will improve patient safety. The recognition and elimination of the tumour is best achieved when anti-tumour lymphocytes are proximal to the malignant cells. For example, the regional secretion of soluble factors, cytotoxic granules, and cell-surface molecule interactions are required for the death of tumour cells and the suppression of neovasculature formation, tumour-associated suppressor, or stromal cells. The resistance of individual tumour cell clones to cellular therapy and the hostile environment of the solid tumours is a major challenge to adoptive cell therapy. We review the strategies that could be useful to overcoming insufficient immune cell migration to the tumour cell mass. We argue that existing 'competitive' approaches should now be revisited as complementary approaches to improve CAR T and NK cell therapy.