T cells expressing chimeric antigen receptors can cause anaphylaxis in humans

Augmenting the landscape of chimeric antigen receptor T-cell therapy

INTRODUCTION

The inception of recombinant DNA technology and live cell genomic alteration have paved the path for the excellence of cell and gene therapies and often provided the first curative treatment for many indications. The approval of the first Chimeric Antigen Receptor (CAR) T-cell therapy was one of the breakthrough innovations that became the headline in 2017. Currently, the therapy is primarily restricted to a few nations, and the market is growing at a CAGR (current annual growth rate) of 11.6% (2022-2032), as opposed to the established bio-therapeutic market at a CAGR of 15.9% (2023-2030). The limited technology democratization is attributed to its autologous nature, lack of awareness, therapy inclusion criteria, high infrastructure cost, trained personnel, complex manufacturing processes, regulatory challenges, recurrence of the disease, and long-term follow-ups.

AREAS COVERED

This review discusses the vision and strategies focusing on the CAR T-cell therapy democratization with mitigation plans. Further, it also covers the strategies to leverage the mRNA-based CAR T platform for building an ecosystem to ensure availability, accessibility, and affordability to the community.

EXPERT OPINION

mRNA-guided CAR T cell therapy is a rapidly growing area wherein a collaborative approach among the stakeholders is needed for its success.

Humanization of the antigen-recognition domain does not impinge on the antigen-binding, cytokine secretion, and antitumor reactivity of humanized nanobody-based CD19-redirected CAR-T cells

BACKGROUND

The immunogenicity of the antigen-recognition domains of chimeric antigen receptor (CAR)-T cells leads to immune responses that may compromise the antitumor effects of the adoptively transferred T cells. Herein, we attempt to humanize a CD19-specific VHH (named H85) using in silico techniques and investigate the impact of antigen-recognition domain humanization on CAR expression and density, cytokine secretion, and cytolytic reactivity of CAR-T cells based on the humanized VHH.

METHODS

H85 was humanized (named HuH85), and then HuH85 was compared with H85 in terms of conformational structure, physicochemical properties, antigenicity and immunogenicity, solubility, flexibility, stability, and CD19-binding capacity using in silico techniques. Next, H85CAR-T cells and HuH85CAR-T cells were developed and CAR expression and surface density were assessed via flow cytometry. Ultimately, the antitumor reactivity and secreted levels of IFN-γ, IL-2, and TNF-α were assessed following the co-cultivation of the CAR-T cells with Ramos, Namalwa, and K562 cells.

RESULTS

In silico findings demonstrated no negative impacts on HuH85 as a result of humanization. Ultimately, H85CAR and HuH85CAR could be surface-expressed on transduced T cells at comparable levels as assessed via mean fluorescence intensity. Moreover, H85CAR-T cells and HuH85CAR-T cells mediated comparable antitumor effects against Ramos and Namalwa cells and secreted comparable levels of IFN-γ, IL-2, and TNF-α following co-cultivation.

CONCLUSION

HuH85 can be used to develop immunotherapeutics against CD19-associated hematologic malignancies. Moreover, HuH85CAR-T cells must be further investigated in vitro and in preclinical xenograft models of CD19+ leukemias and lymphomas before advancing into clinical trials.

Application of CAR-T cell therapy targeting mesothelin in solid tumor treatment

Chimeric antigen receptor (CAR)-T-cell therapy is one of the most effective immunotherapies. CAR-T-cell therapy has achieved great success in the treatment of hematological malignancies. However, due to the characteristics of solid malignant tumors, such as on-target effects, off-tumor toxicity, an immunosuppressive tumor microenvironment (TME), and insufficient trafficking, CAR-T-cell therapy for solid tumors is still in the exploration stage. Mesothelin (MSLN) is a molecule expressed on the surface of various solid malignant tumor cells that is suitable as a target of tumor cells with high MSLN expression for CAR-T-cell therapy. This paper briefly described the development of CAR-T cell therapy and the structural features of MSLN, and especially summarized the strategies of structure optimization of MSLN-targeting CAR-T-cells and the enhancement methods of MSLN-targeting CAR-T cell anti-tumor efficacy by summarizing some preclinical experiment and clinical trials. When considering MSLN-targeting CAR-T-cell therapy as an example, this paper summarizes the efforts made by researchers in CAR-T-cell therapy for solid tumors and summarizes feasible treatment plans by integrating the existing research results.

Development of novel humanized CD19/BAFFR bicistronic chimeric antigen receptor T cells with potent antitumor activity against B-cell lineage neoplasms

Chimeric antigen receptor T cell (CAR-T) therapy has shown remarkable efficacy in treating advanced B-cell malignancies by targeting CD19, but antigen-negative relapses and immune responses triggered by murine-derived antibodies remain significant challenges, necessitating the development of novel humanized multitarget CAR-T therapies. Here, we engineered a second-generation 4-1BB-CD3ζ-based CAR construct incorporating humanized CD19 single-chain variable fragments (scFvs) and BAFFR single-variable domains on heavy chains (VHHs), also known as nanobodies. The resultant CAR-T cells, with different constructs, were functionally compared both in vitro and in vivo. We found that the optimal tandem and bicistronic (BI) structures retained respective antigen-binding abilities, and both demonstrated specific activation when stimulated with target cells. At the same time, BI CAR-T cells (BI CARs) exhibited stronger tumour-killing ability and better secretion of interleukin-2 and tumour necrosis factor-alpha than single-target CAR-T cells. Additionally, BI CARs showed less exhaustion phenotype upon repeated antigen stimulation and demonstrated more potent and persistent antitumor effects in mouse xenograft models. Overall, we developed a novel humanized CD19/BAFFR bicistronic CAR (BI CAR) based on a combination of scFv and VHH, which showed potent and sustained antitumor ability both in vitro and in vivo, including against tumours with CD19 or BAFFR deficiencies.

Engineered CD147-CAR macrophages for enhanced phagocytosis of cancers

Chimeric antigen receptor (CAR) T cell therapy has shown promising results in hematologic malignancies, but its effectiveness in solid cancers remains challenging. Macrophages are immune cells residing within the tumor microenvironment. They can phagocytose tumor cells. Recently, CAR macrophages (CAR-M) have been a promising candidate for treating solid cancers. One of the common cancer antigens overexpressed in various types of cancer is CD147. CAR-T and NK cells targeting CD147 antigen have shown significant efficacy against hepatocellular carcinoma. Nevertheless, CAR-M targeting the CD147 molecule has not been investigated. In this study, we generated CAR targeting the CD147 molecule using the THP-1 monocytic cell line (CD147 CAR-M). The CD147 CAR-M exhibited typical macrophage characteristics, including phagocytosis of zymosan bioparticles and polarization ability toward M1 and M2 phenotypes. Furthermore, the CD147 CAR-M demonstrated enhanced anti-tumor activity against K562 and MDA-MB-231 cells without exhibiting off-target cytotoxicity against normal cells. Our research provides valuable insights into the potential of CD147 CAR-M as a promising platform for cancer immunotherapy, with applications in both hematologic malignancies and solid cancers.

The paths toward non-viral CAR-T cell manufacturing: A comprehensive review of state-of-the-art methods

Although CAR-T cell therapy has emerged as a game-changer in cancer immunotherapy several bottlenecks limit its widespread use as a front-line therapy. Current protocols for the production of CAR-T cells rely mainly on the use of lentiviral/retroviral vectors. Nevertheless, according to the safety concerns around the use of viral vectors, there are several regulatory hurdles to their clinical use. Large-scale production of viral vectors under "Current Good Manufacturing Practice" (cGMP) involves rigorous quality control assessments and regulatory requirements that impose exorbitant costs on suppliers and as a result, lead to a significant increase in the cost of treatment. Pursuing an efficient non-viral method for genetic modification of immune cells is a hot topic in cell-based gene therapy. This study aims to investigate the current state-of-the-art in non-viral methods of CAR-T cell manufacturing. In the first part of this study, after reviewing the advantages and disadvantages of the clinical use of viral vectors, different non-viral vectors and the path of their clinical translation are discussed. These vectors include transposons (sleeping beauty, piggyBac, Tol2, and Tc Buster), programmable nucleases (ZFNs, TALENs, and CRISPR/Cas9), mRNA, plasmids, minicircles, and nanoplasmids. Afterward, various methods for efficient delivery of non-viral vectors into the cells are reviewed.

Optimization Strategies in CAR T-cell Therapy: A Comprehensive Evaluation of Cytopenia, HLH/MAS, and Other Adverse Events

Chimeric antigen receptor (CAR) T-cell therapy has emerged as a transformative treatment for various hematological malignancies. Still, its remarkable efficacy is accompanied by unique adverse events that must be carefully managed. This comprehensive literature review evaluates the safety profile of CAR T-cell therapy, focusing on cytopenia, hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS), and other potential complications. Cytopenia, characterized by reduced blood cell counts, affects a significant proportion of patients, with rates of anemia, neutropenia, and thrombocytopenia reaching up to 60%, 70%, and 80%, respectively. Risk factors include high tumor burden, prior chemotherapy, and bone marrow involvement. Cytokine release syndrome (CRS) occurs in 13% to 77% of patients and is linked to the cytokine storm induced by CAR T cells, target antigen expression, and preexisting immune dysregulation. Other notable adverse events discussed are cytokine release syndrome, neurotoxicity, and infections. Understanding the mechanisms, risk factors, and management strategies for these adverse events is crucial for optimizing patient outcomes and unlocking the full potential of this revolutionary therapy. The review highlights the need for continued research, interdisciplinary collaboration, and evidence-based approaches to enhance the safety and efficacy of CAR T-cell therapy.

Applications and Opportunities for Immune Cell CAR Engineering in Comparative Oncology

Chimeric antigen receptor (CAR) T-adoptive cell therapy has transformed the treatment of human hematologic malignancies. However, its application for the treatment of solid tumors remains challenging. An exciting avenue for advancing this field lies in the use of pet dogs, in which cancers that recapitulate the biology, immunological features, and clinical course of human malignancies arise spontaneously. Moreover, their large size, outbred genetic background, shared environment with humans, and immunocompetency make dogs ideal for investigating and optimizing CAR therapies before human trials. Here, we will outline how challenges in early clinical trials in patients with canine lymphoma, including issues related to autologous CAR T-cell manufacturing, limited CAR T-cell persistence, and tumor antigen escape, mirrored challenges observed in human CAR T trials. We will then highlight emerging adoptive cell therapy strategies currently under investigation in dogs with hematological and solid cancers, which will provide crucial safety and efficacy data on novel CAR T regimens that can be used to support clinical trials. By drawing from ongoing studies, we will illustrate how canine patients with spontaneous cancer may serve as compelling screening platforms to establish innovative CAR therapy approaches and identify predictive biomarkers of response, with a specific emphasis on solid tumors. With increased funding for canine immunotherapy studies, multi-institutional investigations are poised to generate highly impactful clinical data that should translate into more effective human trials, ultimately benefiting both human and canine cancer patients.

Severe anaphylaxis after chimeric antigen receptor T-cell injection: a case report

Anaphylactic reactions at the time of chimeric antigen receptor T (CAR-T) cell infusion are adverse events that have not been reported in pivotal clinical trials or in real-world series. We report the case of patient with severe anaphylaxis with cardiac arrest after tisagenlecleucel injection for Diffuse Large B cell Lymphoma, who recovered after resuscitation and intensive care treatment; we also conducted a Food and Drug Administration Adverse Event Reporting System database analysis and found several cases of severe anaphlyaxis after CAR-T cell injection. Although not reported in pivotal CAR-T cell studies, anaphylaxis can occur after CAR-T cell injection, highlighting the need to include anaphylaxis as a possible side effect in future studies.

Developing a membrane-proximal CD33-targeting CAR T cell

BACKGROUND

CD33 is a tractable target in acute myeloid leukemia (AML) for chimeric antigen receptor (CAR) T cell therapy, but clinical success is lacking.

METHODS

We developed 3P14HLh28Z, a novel CD33-directed CD28/CD3Z-based CAR T cell derived from a high-affinity binder obtained through membrane-proximal fragment immunization in humanized mice.

RESULTS

We found that immunization exclusively with the membrane-proximal domain of CD33 is necessary for identification of membrane-proximal binders in humanized mice. Compared with clinically validated lintuzumab-based CAR T cells targeting distal CD33 epitopes, 3P14HLh28Z showed enhanced in vitro functionality as well as superior tumor control and increased overall survival in both low antigen density and clinically relevant patient-derived xenograft models. Increased activation and enhanced polyfunctionality led to enhanced efficacy.

CONCLUSIONS

Showing for the first time that a membrane-proximal CAR is superior to a membrane-distal one in the setting of CD33 targeting, our results demonstrate the rationale for targeting membrane-proximal epitopes with high-affinity binders. We also demonstrate the importance of optimizing CAR T cells for functionality in settings of both low antigen density and clinically relevant patient-derived models.

Mesothelin CAR T Cells Secreting Anti-FAP/Anti-CD3 Molecules Efficiently Target Pancreatic Adenocarcinoma and its Stroma

PURPOSE

Targeting solid tumors with chimeric antigen receptor (CAR) T cells remains challenging due to heterogenous target antigen expression, antigen escape, and the immunosuppressive tumor microenvironment (TME). Pancreatic cancer is characterized by a thick stroma generated by cancer-associated fibroblasts (CAF), which may contribute to the limited efficacy of mesothelin-directed CAR T cells in early-phase clinical trials. To provide a more favorable TME for CAR T cells to target pancreatic ductal adenocarcinoma (PDAC), we generated T cells with an antimesothelin CAR and a secreted T-cell-engaging molecule (TEAM) that targets CAF through fibroblast activation protein (FAP) and engages T cells through CD3 (termed mesoFAP CAR-TEAM cells).

EXPERIMENTAL DESIGN

Using a suite of in vitro, in vivo, and ex vivo patient-derived models containing cancer cells and CAF, we examined the ability of mesoFAP CAR-TEAM cells to target PDAC cells and CAF within the TME. We developed and used patient-derived ex vivo models, including patient-derived organoids with patient-matched CAF and patient-derived organotypic tumor spheroids.

RESULTS

We demonstrated specific and significant binding of the TEAM to its respective antigens (CD3 and FAP) when released from mesothelin-targeting CAR T cells, leading to T-cell activation and cytotoxicity of the target cell. MesoFAP CAR-TEAM cells were superior in eliminating PDAC and CAF compared with T cells engineered to target either antigen alone in our ex vivo patient-derived models and in mouse models of PDAC with primary or metastatic liver tumors.

CONCLUSIONS

CAR-TEAM cells enable modification of tumor stroma, leading to increased elimination of PDAC tumors. This approach represents a promising treatment option for pancreatic cancer.

Recent advances in CAR-T cell therapy for acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a fatal and refractory haematologic cancer that primarily affects adults. It interferes with bone marrow cell proliferation. Patients have a 5 years survival rate of less than 30% despite the availability of several treatments, including chemotherapy, allogeneic haematopoietic stem cell transplantation (Allo-HSCT), and receptor antagonist drugs. Allo-HSCT is the mainstay of acute myeloid leukaemia treatment. Although it does work, there are severe side effects, such as graft-versus-host disease (GVHD). In recent years, chimeric antigen receptor (CAR)-T cell therapies have made significant progress in the treatment of cancer. These engineered T cells can locate and recognize tumour cells in vivo and release a large number of effectors through immune action to effectively kill tumour cells. CAR-T cells are among the most effective cancer treatments because of this property. CAR-T cells have demonstrated positive therapeutic results in the treatment of acute myeloid leukaemia, according to numerous clinical investigations. This review highlights recent progress in new targets for AML immunotherapy, and the limitations, and difficulties of CAR-T therapy for AML.

Non-viral delivery of RNA for therapeutic T cell engineering

Adoptive T cell transfer has shown great success in treating blood cancers, resulting in a growing number of FDA-approved therapies using chimeric antigen receptor (CAR)-engineered T cells. However, the effectiveness of this treatment for solid tumors is still not satisfactory, emphasizing the need for improved T cell engineering strategies and combination approaches. Currently, CAR T cells are mainly manufactured using gammaretroviral and lentiviral vectors due to their high transduction efficiency. However, there are concerns about their safety, the high cost of producing them in compliance with current Good Manufacturing Practices (cGMP), regulatory obstacles, and limited cargo capacity, which limit the broader use of engineered T cell therapies. To overcome these limitations, researchers have explored non-viral approaches, such as membrane permeabilization and carrier-mediated methods, as more versatile and sustainable alternatives for next-generation T cell engineering. Non-viral delivery methods can be designed to transport a wide range of molecules, including RNA, which allows for more controlled and safe modulation of T cell phenotype and function. In this review, we provide an overview of non-viral RNA delivery in adoptive T cell therapy. We first define the different types of RNA therapeutics, highlighting recent advancements in manufacturing for their therapeutic use. We then discuss the challenges associated with achieving effective RNA delivery in T cells. Next, we provide an overview of current and emerging technologies for delivering RNA into T cells. Finally, we discuss ongoing preclinical and clinical studies involving RNA-modified T cells.

The mast cell-T lymphocyte axis impacts cancer: Friend or foe?

Crosstalk between mast cells (MCs) and T lymphocytes (TLs) releases specific signals that create an environment conducive to tumor development. Conversely, they can protect against cancer by targeting tumor cells for destruction. Although their role in immunity and cancer is complex, their potential in anticancer strategies is often underestimated. When peripheral MCs are activated, they can affect cancer development. Tumor-infiltrating TLs may malfunction and contribute to aggressive cancer and poor prognoses. One promising approach for cancer patients is TL-based immunotherapies. Recent reports suggest that MCs modulate TL activity in solid tumors and may be a potential therapeutic layer in multitargeting anticancer strategies. Pharmacologically modulating MC activity can enhance the anticancer cytotoxic TL response in tumors. By identifying tumor-specific targets, it has been possible to genetically alter patients' cells into fully humanized anticancer cellular therapies for autologous transplantation, including the engineering of TLs and MCs to target and kill cancer cells. Hence, recent scientific evidence provides a broader understanding of MC-TL activity in cancer.

Development of nanobodies targeting hepatocellular carcinoma and application of nanobody-based CAR-T technology

BACKGROUND

Chimeric antigen receptor T (CAR-T) cell therapy, as an emerging anti-tumor treatment, has garnered extensive attention in the study of targeted therapy of multiple tumor-associated antigens in hepatocellular carcinoma (HCC). However, the suppressive microenvironment and individual heterogeneity results in downregulation of these antigens in certain patients' cancer cells. Therefore, optimizing CAR-T cell therapy for HCC is imperative.

METHODS

In this study, we administered FGFR4-ferritin (FGFR4-HPF) nanoparticles to the alpaca and constructed a phage library of nanobodies (Nbs) derived from alpaca, following which we screened for Nbs targeting FGFR4. Then, we conducted the functional validation of Nbs. Furthermore, we developed Nb-derived CAR-T cells and evaluated their anti-tumor ability against HCC through in vitro and in vivo validation.

RESULTS

Our findings demonstrated that we successfully obtained high specificity and high affinity Nbs targeting FGFR4 after screening. And the specificity of Nbs targeting FGFR4 was markedly superior to their binding to other members of the FGFR family proteins. Furthermore, the Nb-derived CAR-T cells, targeting FGFR4, exhibited significantly enhanced anti-tumor efficacy in both experiments when in vitro and in vivo.

CONCLUSIONS

In summary, the results of this study suggest that the CAR-T cells derived from high specificity and high affinity Nbs, targeting FGFR4, exhibited significantly enhanced anti-tumor efficacy in vitro and in vivo. This is an exploration of FGFR4 in the field of Nb-derived CAR-T cell therapy for HCC, holding promise for enhancing safety and effectiveness in the clinical treatment of HCC in the future.

Selection, engineering, and in vivo testing of a human leukocyte antigen-independent T-cell receptor recognizing human mesothelin

BACKGROUND

Canonical α/β T-cell receptors (TCRs) bind to human leukocyte antigen (HLA) displaying antigenic peptides to elicit T cell-mediated cytotoxicity. TCR-engineered T-cell immunotherapies targeting cancer-specific peptide-HLA complexes (pHLA) are generating exciting clinical responses, but owing to HLA restriction they are only able to target a subset of antigen-positive patients. More recently, evidence has been published indicating that naturally occurring α/β TCRs can target cell surface proteins other than pHLA, which would address the challenges of HLA restriction. In this proof-of-concept study, we sought to identify and engineer so-called HLA-independent TCRs (HiTs) against the tumor-associated antigen mesothelin.

METHODS

Using phage display, we identified a HiT that bound well to mesothelin, which when expressed in primary T cells, caused activation and cytotoxicity. We subsequently engineered this HiT to modulate the T-cell response to varying levels of mesothelin on the cell surface.

RESULTS

The isolated HiT shows cytotoxic activity and demonstrates killing of both mesothelin-expressing cell lines and patient-derived xenograft models. Additionally, we demonstrated that HiT-transduced T cells do not require CD4 or CD8 co-receptors and, unlike a TCR fusion construct, are not inhibited by soluble mesothelin. Finally, we showed that HiT-transduced T cells are highly efficacious in vivo, completely eradicating xenografted human solid tumors.

CONCLUSION

HiTs can be isolated from fully human TCR-displaying phage libraries against cell surface-expressed antigens. HiTs are able to fully activate primary T cells both in vivo and in vitro. HiTs may enable the efficacy seen with pHLA-targeting TCRs in solid tumors to be translated to cell surface antigens.

Chimeric antigen receptor T cells in the treatment of osteosarcoma (Review)

Osteosarcoma (OS) is a frequently occurring primary bone tumor, mostly affecting children, adolescents and young adults. Before 1970, surgical resection was the main treatment method for OS, but the clinical results were not promising. Subsequently, the advent of chemotherapy has improved the prognosis of patients with OS. However, there is still a high incidence of metastasis or recurrence, and chemotherapy has several side effects, thus making the 5‑year survival rate markedly low. Recently, chimeric antigen receptor T (CAR‑T) cell therapy represents an alternative immunotherapy approach with significant potential for hematologic malignancies. Nevertheless, the application of CAR‑T cells in the treatment of OS faces numerous challenges. The present review focused on the advances in the development of CAR‑T cells to improve their clinical efficacy, and discussed ways to overcome the difficulties faced by CAR T‑cell therapy for OS.

Recent advances in CAR T-cell engineering using synthetic biology: Paving the way for next-generation cancer treatment

This book chapter highlights a comprehensive exploration of the transformative innovations in the field of cancer immunotherapy. CAR (Chimeric Antigen Receptor) T-cell therapy represents a groundbreaking approach to treat cancer by reprogramming a patient immune cells to recognize and destroy cancer cells. This chapter underscores the critical role of synthetic biology in enhancing the safety and effectiveness of CAR T-cell therapies. It begins by emphasizing the growing importance of personalized medicine in cancer treatment, emphasizing the shift from one-size-fits-all approaches to patient-specific solutions. Synthetic biology, a multidisciplinary field, has been instrumental in customizing CAR T-cell therapies, allowing for fine-tuned precision and minimizing unwanted side effects. The chapter highlights recent advances in gene editing, synthetic gene circuits, and molecular engineering, showcasing how these technologies are optimizing CAR T-cell function. In summary, this book chapter sheds light on the remarkable progress made in the development of CAR T-cell therapies using synthetic biology, providing hope for cancer patients and hinting at a future where highly personalized and effective cancer treatments are the norm.

Mutation-specific CAR T cells as precision therapy for IGLV3-21R110 expressing high-risk chronic lymphocytic leukemia

The concept of precision cell therapy targeting tumor-specific mutations is appealing but requires surface-exposed neoepitopes, which is a rarity in cancer. B cell receptors (BCR) of mature lymphoid malignancies are exceptional in that they harbor tumor-specific-stereotyped sequences in the form of point mutations that drive self-engagement of the BCR and autologous signaling. Here, we use a BCR light chain neoepitope defined by a characteristic point mutation (IGLV3-21R110) for selective targeting of a poor-risk subset of chronic lymphocytic leukemia (CLL) with chimeric antigen receptor (CAR) T cells. We develop murine and humanized CAR constructs expressed in T cells from healthy donors and CLL patients that eradicate IGLV3-21R110 expressing cell lines and primary CLL cells, but neither cells expressing the non-pathogenic IGLV3-21G110 light chain nor polyclonal healthy B cells. In vivo experiments confirm epitope-selective cytolysis in xenograft models in female mice using engrafted IGLV3-21R110 expressing cell lines or primary CLL cells. We further demonstrate in two humanized mouse models lack of cytotoxicity towards human B cells. These data provide the basis for advanced approaches of resistance-preventive and biomarker-guided cellular targeting of functionally relevant lymphoma driver mutations sparing normal B cells.

CRISPR-Cas9: A Potent Gene-editing Tool for the Treatment of Cancer

The prokaryotic adaptive immune system has clustered regularly interspaced short palindromic repeat. CRISPR-associated protein (CRISPR-Cas) genome editing systems have been harnessed. A robust programmed technique for efficient and accurate genome editing and gene targeting has been developed. Engineered cell therapy, in vivo gene therapy, animal modeling, and cancer diagnosis and treatment are all possible applications of this ground-breaking approach. Multiple genetic and epigenetic changes in cancer cells induce malignant cell growth and provide chemoresistance. The capacity to repair or ablate such mutations has enormous potential in the fight against cancer. The CRISPR-Cas9 genome editing method has recently become popular in cancer treatment research due to its excellent efficiency and accuracy. The preceding study has shown therapeutic potential in expanding our anticancer treatments by using CRISPR-Cas9 to directly target cancer cell genomic DNA in cellular and animal cancer models. In addition, CRISPR-Cas9 can combat oncogenic infections and test anticancer medicines. It may design immune cells and oncolytic viruses for cancer immunotherapeutic applications. In this review, these preclinical CRISPRCas9- based cancer therapeutic techniques are summarised, along with the hurdles and advancements in converting therapeutic CRISPR-Cas9 into clinical use. It will increase their applicability in cancer research.

CAR T cell therapy for patients with solid tumours: key lessons to learn and unlearn

Chimeric antigen receptor (CAR) T cells have been approved for use in patients with B cell malignancies or relapsed and/or refractory multiple myeloma, yet efficacy against most solid tumours remains elusive. The limited imaging and biopsy data from clinical trials in this setting continues to hinder understanding, necessitating a reliance on imperfect preclinical models. In this Perspective, I re-evaluate current data and suggest potential pathways towards greater success, drawing lessons from the few successful trials testing CAR T cells in patients with solid tumours and the clinical experience with tumour-infiltrating lymphocytes. The most promising approaches include the use of pluripotent stem cells, co-targeting multiple mechanisms of immune evasion, employing multiple co-stimulatory domains, and CAR ligand-targeting vaccines. An alternative strategy focused on administering multiple doses of short-lived CAR T cells in an attempt to pre-empt exhaustion and maintain a functional effector pool should also be considered.

Electroporation of mRNA as a Universal Technology Platform to Transfect a Variety of Primary Cells with Antigens and Functional Proteins

Electroporation (EP) of mRNA into human cells is a broadly applicable method to transiently express proteins of choice in a variety of different cell types. We have spent more than two decades to optimize and adapt this method, first for antigen-loading of dendritic cells (DCs) and subsequently for T cells, B cells, bulk PBMCs, and several cell lines. In this regard, antigens were introduced, processed, and presented in context of MHC class I and II. Next to that, functional proteins like adhesion receptors, T-cell receptors (TCRs), chimeric antigen receptors (CARs), constitutively active signal transducers (i.e. caIKK), and others were successfully expressed. We have also established this protocol under full GMP compliance as part of a manufacturing license to produce mRNA-electroporated DCs and mRNA-electroporated T cells for therapeutic applications in clinical trials. Therefore, we here want to share our universal mRNA electroporation protocol and the experience we have gathered with this method. The advantages of the transfection method presented here are: (1) easy adaptation to different cell types; (2) scalability from 106 to approximately 108 cells per shot; (3) high transfection efficiency (80-99%); (4) homogenous protein expression; (5) GMP compliance if the EP is performed in a class A clean room; and (6) no transgene integration into the genome. The provided protocol involves: OptiMEM® as EP medium, a square-wave pulse with 500 V, and 4 mm cuvettes. To adapt the protocol to differently sized cells, simply the pulse time has to be altered. Thus, we share an overview of proven electroporation settings (including recovery media), which we have established for various cell types. Next to the basic protocol, we also provide an extensive list of hints and tricks, which, in our opinion, are of great value for everyone who intends to use this transfection technique.

Evolving CAR-T-Cell Therapy for Cancer Treatment: From Scientific Discovery to Cures

In recent years, chimeric antigen receptor (CAR)-T-cell therapy has emerged as the most promising immunotherapy for cancer that typically uses patients' T cells and genetically engineered them to target cancer cells. Although recent improvements in CAR-T-cell therapy have shown remarkable success for treating hematological malignancies, the heterogeneity in tumor antigens and the immunosuppressive nature of the tumor microenvironment (TME) limits its efficacy in solid tumors. Despite the enormous efforts that have been made to make CAR-T-cell therapy more effective and have minimal side effects for treating hematological malignancies, more research needs to be conducted regarding its use in the clinic for treating various other types of cancer. The main concern for CAR-T-cell therapy is severe toxicities due to the cytokine release syndrome, whereas the other challenges are associated with complexity and immune-suppressing TME, tumor antigen heterogeneity, the difficulty of cell trafficking, CAR-T-cell exhaustion, and reduced cytotoxicity in the tumor site. This review discussed the latest discoveries in CAR-T-cell therapy strategies and combination therapies, as well as their effectiveness in different cancers. It also encompasses ongoing clinical trials; current challenges regarding the therapeutic use of CAR-T-cell therapy, especially for solid tumors; and evolving treatment strategies to improve the therapeutic application of CAR-T-cell therapy.

Journey of CAR T‑cells: Emphasising the concepts and advancements in breast cancer (Review)

Cancer is the primary and one of the most prominent causes of the rising global mortality rate, accounting for nearly 10 million deaths annually. Specific methods have been devised to cure cancerous tumours. Effective therapeutic approaches must be developed, both at the cellular and genetic level. Immunotherapy offers promising results by providing sustained remission to patients with refractory malignancies. Genetically modified T‑lymphocytic cells have emerged as a novel therapeutic approach for the treatment of solid tumours, haematological malignancies, and relapsed/refractory B‑lymphocyte malignancies as a result of recent clinical trial findings; the treatment is referred to as chimeric antigen receptor T‑cell therapy (CAR T‑cell therapy). Leukapheresis is used to remove T‑lymphocytes from the leukocytes, and CARs are created through genetic engineering. Without the aid of a major histocompatibility complex, these genetically modified receptors lyse malignant tissues by interacting directly with the carcinogen. Additionally, the outcomes of preclinical and clinical studies reveal that CAR T‑cell therapy has proven to be a potential therapeutic contender against metastatic breast cancer (BCa), triple‑negative, and HER 2+ve BCa. Nevertheless, unique toxicities, including (cytokine release syndrome, on/off‑target tumour recognition, neurotoxicities, anaphylaxis, antigen escape in BCa, and the immunosuppressive tumour microenvironment in solid tumours, negatively impact the mechanism of action of these receptors. In this review, the potential of CAR T‑cell immunotherapy and its method of destroying tumour cells is explored using data from preclinical and clinical trials, as well as providing an update on the approaches used to reduce toxicities, which may improve or broaden the effectiveness of the therapies used in BCa.

Chimeric Antigen Receptor T-Cell Therapy for Solid Tumors

We review chimeric antigen receptor (CAR) T-cell therapy for solid tumors. We discuss patient selection factors and aspects of clinical management. We describe challenges including physical and molecular barriers to trafficking CAR-Ts, an immunosuppressive tumor microenvironment, and difficulty finding cell surface target antigens. The application of new approaches in synthetic biology and cellular engineering toward solid tumor CAR-Ts is described. Finally, we summarize reported and ongoing clinical trials of CAR-T therapies for select disease sites such as head and neck (including thyroid cancer), lung, central nervous system (glioblastoma, neuroblastoma, glioma), sarcoma, genitourinary (prostate, renal, bladder, kidney), breast and ovarian cancer.

Broadly neutralizing antibodies targeting HIV: Progress and challenges

Anti-HIV broadly neutralizing antibodies (bNAbs) offer a novel approach to treating, preventing, or curing HIV. Pre-clinical models and clinical trials involving the passive transfer of bNAbs have demonstrated that they can control viremia and potentially serve as alternatives or complement antiretroviral therapy (ART). However, antibody decay, persistent latent reservoirs, and resistance impede bNAb treatment. This review discusses recent advancements and obstacles in applying bNAbs and proposes strategies to enhance their therapeutic potential. These strategies include multi-epitope targeting, antibody half-life extension, combining with current and newer antiretrovirals, and sustained antibody secretion.

Advancing the frontiers of adaptive cell therapy: A transformative mechanistic journey from preclinical to clinical settings

Although the concept of using the patient's immune system to combat cancer has been around for a while, it is only in recent times that substantial progress has been achieved in this field. Over the last ten years, there has been a significant advancement in the treatment of cancer through immune checkpoint blockade. This treatment has been approved for multiple types of tumors. Another approach to modifying the immune system to detect tumor cells and fight them off is adaptive cell therapy (ACT). This therapy involves using T cells that have been modified with either T cell receptors (TCR) or chimeric antigen receptors (CAR) to target the tumor cells. ACT has demonstrated encouraging outcomes in different types of tumors, and clinical trials are currently underway worldwide to enhance this form of treatment. This review focuses on the advancements that have been made in ACT from preclinical to clinical settings till now.

Framework humanization optimizes potency of anti-CD72 nanobody CAR-T cells for B-cell malignancies

BACKGROUND

Approximately 50% of patients who receive anti-CD19 CAR-T cells relapse, and new immunotherapeutic targets are urgently needed. We recently described CD72 as a promising target in B-cell malignancies and developed nanobody-based CAR-T cells (nanoCARs) against it. This cellular therapy design is understudied compared with scFv-based CAR-T cells, but has recently become of significant interest given the first regulatory approval of a nanoCAR in multiple myeloma.

METHODS

We humanized our previous nanobody framework regions, derived from llama, to generate a series of humanized anti-CD72 nanobodies. These nanobody binders were inserted into second-generation CD72 CAR-T cells and were evaluated against preclinical models of B cell acute lymphoblastic leukemia and B cell non-Hodgkin's lymphoma in vitro and in vivo. Humanized CD72 nanoCARs were compared with parental ("NbD4") CD72 nanoCARs and the clinically approved CD19-directed CAR-T construct tisangenlecleucel. RNA-sequencing, flow cytometry, and cytokine secretion profiling were used to determine differences between the different CAR constructs. We then used affinity maturation on the parental NbD4 construct to generate high affinity binders against CD72 to test if higher affinity to CD72 improved antitumor potency.

RESULTS

Toward clinical translation, here we humanize our previous nanobody framework regions, derived from llama, and surprisingly discover a clone ("H24") with enhanced potency against B-cell tumors, including patient-derived samples after CD19 CAR-T relapse. Potentially underpinning improved potency, H24 has moderately higher binding affinity to CD72 compared with a fully llama framework. However, further affinity maturation (KD<1 nM) did not lead to improvement in cytotoxicity. After treatment with H24 nanoCARs, in vivo relapse was accompanied by CD72 antigen downregulation which was partially reversible. The H24 nanobody clone was found to have no off-target binding and is therefore designated as a true clinical candidate.

CONCLUSION

This work supports translation of H24 CD72 nanoCARs for refractory B-cell malignancies, reveals potential mechanisms of resistance, and unexpectedly demonstrates that nanoCAR potency can be improved by framework alterations alone. These findings may have implications for future engineering of nanobody-based cellular therapies.

Recruiting In Vitro Transcribed mRNA against Cancer Immunotherapy: A Contemporary Appraisal of the Current Landscape

Over 100 innovative in vitro transcribed (IVT)-mRNAs are presently undergoing clinical trials, with a projected substantial impact on the pharmaceutical market in the near future. Τhe idea behind this is that after the successful cellular internalization of IVT-mRNAs, they are subsequently translated into proteins with therapeutic or prophylactic relevance. Simultaneously, cancer immunotherapy employs diverse strategies to mobilize the immune system in the battle against cancer. Therefore, in this review, the fundamental principles of IVT-mRNA to its recruitment in cancer immunotherapy, are discussed and analyzed. More specifically, this review paper focuses on the development of mRNA vaccines, the exploitation of neoantigens, as well as Chimeric Antigen Receptor (CAR) T-Cells, showcasing their clinical applications and the ongoing trials for the development of next-generation immunotherapeutics. Furthermore, this study investigates the synergistic potential of combining the CAR immunotherapy and the IVT-mRNAs by introducing our research group novel, patented delivery method that utilizes the Protein Transduction Domain (PTD) technology to transduce the IVT-mRNAs encoding the CAR of interest into the Natural Killer (NK)-92 cells, highlighting the potential for enhancing the CAR NK cell potency, efficiency, and bioenergetics. While IVT-mRNA technology brings exciting progress to cancer immunotherapy, several challenges and limitations must be acknowledged, such as safety, toxicity, and delivery issues. This comprehensive exploration of IVT-mRNA technology, in line with its applications in cancer therapeutics, offers valuable insights into the opportunities and challenges in the evolving landscape of cancer immunotherapy, setting the stage for future advancements in the field.

CAR-T Cell Therapy in the Treatment of Pediatric Non-Hodgkin Lymphoma

Non-Hodgkin lymphomas (NHL) are a group of cancers that originate in the lymphatic system, especially from progenitor or mature B-cells, T-cells, or natural killer (NK) cells. NHL is the most common hematological malignancy worldwide and also the fourth most frequent type of cancer among pediatric patients. This cancer can occur in children of any age, but it is quite rare under the age of 5 years. In recent decades, available medicines and therapies have significantly improved the prognosis of patients with this cancer. However, some cases of NHL are treatment resistant. For this reason, immunotherapy, as a more targeted and personalized treatment strategy, is becoming increasingly important in the treatment of NHL in pediatric patients. The objective of the following review is to gather the latest available research results, conducted among pediatric and/or adult patients with NHL, regarding one immunotherapy method, i.e., chimeric antigen receptor (CAR) T cell therapy. We focus on assessing the effectiveness of CAR-T cell therapy, which mainly targets B cell markers, CD19, CD20, and CD22, their connections with one another, sequential treatment, or connections with co-stimulatory molecules. In addition, we also evaluate the safety, aftermath (especially neurotoxicities) and limitations of CAR-T cell therapy.

Humanized single-domain antibody targeting HER2 enhances function of chimeric antigen receptor T cells

Introduction

Chimeric antigen receptors (CARs) can redirect T cells against antigen-expressing tumors, and each component plays an important role in the function and anti-tumor efficacy. It has been reported that using human sequences or a low affinity of CAR single-chain variable fragments (scFvs) in the CAR binding domains is a potential way to enhance the function of CAR-T cells. However, it remains largely unknown how a lower affinity of CARs using humanized scFvs affects the function of CAR-T cells until recently.

Methods

We used different humanized anti-HER2 antibodies as the extracellular domain of CARs and further constructed a series of the CAR-T cells with different affinity.

Results

We have observed that moderately reducing the affinity of CARs (light chain variable domain (VL)-based CAR-T) could maintain the anti-tumor efficacy, and improved the safety of CAR therapy both in vitro and in vivo compared with high-affinity CAR-T cells. Moreover, T cells expressing the VL domain only antibody exhibited long-lasting tumor elimination capability after multiple challenges in vitro, longer persistence and lower cytokine levels in vivo.

Discussion

Our findings provide an alternative option for CAR-T optimization with the potential to widen the use of CAR T cells.

Toward the clinical development of synthetic immunity to cancer

Synthetic biology (synbio) tools, such as chimeric antigen receptors (CARs), have been designed to target, activate, and improve immune cell responses to tumors. These therapies have demonstrated an ability to cure patients with blood cancers. However, there are significant challenges to designing, testing, and efficiently translating these complex cell therapies for patients who do not respond or have immune refractory solid tumors. The rapid progress of synbio tools for cell therapy, particularly for cancer immunotherapy, is encouraging but our development process should be tailored to increase translational success. Particularly, next-generation cell therapies should be rooted in basic immunology, tested in more predictive preclinical models, engineered for potency with the right balance of safety, educated by clinical findings, and multi-faceted to combat a range of suppressive mechanisms. Here, we lay out five principles for engineering future cell therapies to increase the probability of clinical impact, and in the context of these principles, we provide an overview of the current state of synbio cell therapy design for cancer. Although these principles are anchored in engineering immune cells for cancer therapy, we posit that they can help guide translational synbio research for broad impact in other disease indications with high unmet need.

Complete spectrum of adverse events associated with chimeric antigen receptor (CAR)-T cell therapies

Chimeric antigen receptor (CAR)-T cell therapies have been approved by FDA to treat relapsed or refractory hematological malignancies. However, the adverse effects of CAR-T cell therapies are complex and can be challenging to diagnose and treat. In this review, we summarize the major adverse events, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and CAR T-cell associated HLH (carHLH), and discuss their pathophysiology, symptoms, grading, and diagnosis systems, as well as management. In a future outlook, we also provide an overview of measures and modifications to CAR-T cells that are currently being explored to limit toxicity.

Conditional Control of Universal CAR T Cells by Cleavable OFF-Switch Adaptors

As living drugs, engineered T cell therapies are revolutionizing disease treatment with their unique functional capabilities. However, they suffer from limitations of potentially unpredictable behavior, toxicities, and nontraditional pharmacokinetics. Engineering conditional control mechanisms responsive to tractable stimuli such as small molecules or light is thus highly desirable. We and others previously developed "universal" chimeric antigen receptors (CARs) that interact with coadministered antibody adaptors to direct target cell killing and T cell activation. Universal CARs are of high therapeutic interest due to their ability to simultaneously target multiple antigens on the same disease or different diseases by combining with adaptors to different antigens. Here, we further enhance the programmability and potential safety of universal CAR T cells by engineering OFF-switch adaptors that can conditionally control CAR activity, including T cell activation, target cell lysis, and transgene expression, in response to a small molecule or light stimulus. Moreover, in adaptor combination assays, OFF-switch adaptors were capable of orthogonal conditional targeting of multiple antigens simultaneously, following Boolean logic. OFF-switch adaptors represent a robust new approach for the precision targeting of universal CAR T cells with potential for enhanced safety.

CD24 is a novel target of chimeric antigen receptor T cells for the treatment of triple negative breast cancer

Triple negative breast cancer (TNBC) is a subtype of breast cancer with the highest degree of malignancy and the worst prognosis. The application of immunotherapy for TNBC is limited. This study was to verify the potential application of chimeric antigen receptor-T cells (CAR-T cells) targeting CD24 named as 24BBz in treatment of TNBC. 24BBz was constructed by lentivirus infection and then was co-culture with breast cancer cell lines to evaluate the activation, proliferation and cytotoxicity of engineered T cells. The anti-tumor activity of 24BBz was verified in the subcutaneous xenograft model of nude mice. We found that CD24 gene was significantly up-regulated in breast cancer (BRCA), especially in TNBC. 24BBz showed antigen-specific activation and dose-dependent cytotoxicity against CD24-positive BRCA tumor cells in vitro. Furthermore, 24BBz showed significant anti-tumor effect in CD24-positive TNBC xenografts and T cells infiltration in tumor tissues, while some T cells exhibited exhaustion. No pathological damage of major organs was found during the treatment. This study proved that CD24-specific CAR-T cells have potent anti-tumor activity and potential application value in treatment of TNBC.

Bringing cell therapy to tumors: considerations for optimal CAR binder design

Chimeric antigen receptor (CAR)-T cells have revolutionized the immunotherapy of B-cell malignancies and are poised to expand the range of their impact across a broad range of oncology and non-oncology indications. Critical to the success of a given CAR is the choice of binding domain, as this is the key driver for specificity and plays an important role (along with the rest of the CAR structure) in determining efficacy, potency and durability of the cell therapy. While antibodies have proven to be effective sources of CAR binding domains, it has become apparent that the desired attributes for a CAR binding domain do differ from those of a recombinant antibody. This review will address key factors that need to be considered in choosing the optimal binding domain for a given CAR and how binder properties influence and are influenced by the rest of the CAR.

Exploring CAR-T Cell Therapy Side Effects: Mechanisms and Management Strategies

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of malignancies, especially hematological tumors, but toxicities have tempered its success. The main impediments to the development of CAR-T cell therapies are the following: cytokine release syndrome (CRS), immune-effector-cell-associated neurotoxicity syndrome (ICANS), tumor lysis syndrome (TLS), and on-target/off-tumor toxicity (OTOT). This review summarizes these side effects' underlying mechanisms and manifestations over time. It provides potential prevention and treatment according to the consensus grading, stressing the significance of establishing strategies that anticipate, reduce, and navigate the beginning of these side effects. It is essential to fully comprehend the mechanisms underlying these toxicities to create efficient treatment and preventive approaches.

The future of affordable cancer immunotherapy

The treatment of cancer was revolutionized within the last two decades by utilizing the mechanism of the immune system against malignant tissue in so-called cancer immunotherapy. Two main developments boosted cancer immunotherapy: 1) the use of checkpoint inhibitors, which are characterized by a relatively high response rate mainly in solid tumors; however, at the cost of serious side effects, and 2) the use of chimeric antigen receptor (CAR)-T cells, which were shown to be very efficient in the treatment of hematologic malignancies, but failed to show high clinical effectiveness in solid tumors until now. In addition, active immunization against individual tumors is emerging, and the first products have reached clinical approval. These new treatment options are very cost-intensive and are not financially compensated by health insurance in many countries. Hence, strategies must be developed to make cancer immunotherapy affordable and to improve the cost-benefit ratio. In this review, we discuss the following strategies: 1) to leverage the antigenicity of "cold tumors" with affordable reagents, 2) to use microbiome-based products as markers or therapeutics, 3) to apply measures that make adoptive cell therapy (ACT) cheaper, e.g., the use of off-the-shelf products, 4) to use immunotherapies that offer cheaper platforms, such as RNA- or peptide-based vaccines and vaccines that use shared or common antigens instead of highly personal antigens, 5) to use a small set of predictive biomarkers instead of the "sequence everything" approach, and 6) to explore affordable immunohistochemistry markers that may direct individual therapies.

Engineering natural molecule-triggered genetic control systems for tunable gene- and cell-based therapies

The ability to precisely control activities of engineered designer cells provides a novel strategy for modern precision medicine. Dynamically adjustable gene- and cell-based precision therapies are recognized as next generation medicines. However, the translation of these controllable therapeutics into clinical practice is severely hampered by the lack of safe and highly specific genetic switches controlled by triggers that are nontoxic and side-effect free. Recently, natural products derived from plants have been extensively explored as trigger molecules to control genetic switches and synthetic gene networks for multiple applications. These controlled genetic switches could be further introduced into mammalian cells to obtain synthetic designer cells for adjustable and fine tunable cell-based precision therapy. In this review, we introduce various available natural molecules that were engineered to control genetic switches for controllable transgene expression, complex logic computation, and therapeutic drug delivery to achieve precision therapy. We also discuss current challenges and prospects in translating these natural molecule-controlled genetic switches developed for biomedical applications from the laboratory to the clinic.

CAR-T in the Treatment of Acute Myeloid Leukemia: Barriers and How to Overcome Them

Conventional therapies for acute myeloid leukemia (AML) are characterized by high rates of relapse, severe toxicities, and poor overall survival rates. Thus, the development of new therapeutic strategies is crucial for improving the survival and quality of life of AML patients. CD19-directed chimeric antigen receptor (CAR) T-cell immunotherapy has been extremely successful in the treatment of B-cell acute lymphoid leukemia and several mature B-cell lymphomas. However, the use of CAR T-cell therapy for AML is currently prevented due to the lack of a myeloid equivalent to CD19, as currently known cell surface targets on leukemic blasts are also expressed on healthy hematopoietic stem and progenitor cells as well as their progeny. In addition, the immunosuppressive tumor microenvironment has a dampening effect on the antitumor activity of CAR-T cells. Here, we review the therapeutic challenges limiting the use of CAR T-cell therapy for AML and discuss promising novel strategies to overcome them.

Targeted Approaches to Treatment of Pleural Mesothelioma: A Review

Pleural mesothelioma is an aggressive disease that is enriched for inactivating alterations in tumor suppressor genes. Systemic therapeutic strategies for pleural mesothelioma generally involve chemotherapies and immunotherapies that are chosen without consideration of the tumor's molecular profile. As this generalized approach to treatment rarely yields durable responses, alternative therapeutic regimens are urgently indicated. Preclinical studies have identified synthetic lethal protein and metabolic interactions, recurrently overexpressed proteins, and frequent pathway perturbations that may be therapeutically exploited in mesothelioma. This review discusses the mechanism of action of emerging investigational therapies and summarizes findings from phase I-II clinical trials exploring selective, biomarker-driven therapeutic strategies for mesothelioma, with a focus on five common targets. Finally, using lessons learned from these clinical trials, imperatives for successful implementation of targeted therapy in mesothelioma are discussed.

Immunotherapy in hematologic malignancies: achievements, challenges and future prospects

The immune-cell origin of hematologic malignancies provides a unique avenue for the understanding of both the mechanisms of immune responsiveness and immune escape, which has accelerated the progress of immunotherapy. Several categories of immunotherapies have been developed and are being further evaluated in clinical trials for the treatment of blood cancers, including stem cell transplantation, immune checkpoint inhibitors, antigen-targeted antibodies, antibody-drug conjugates, tumor vaccines, and adoptive cell therapies. These immunotherapies have shown the potential to induce long-term remission in refractory or relapsed patients and have led to a paradigm shift in cancer treatment with great clinical success. Different immunotherapeutic approaches have their advantages but also shortcomings that need to be addressed. To provide clinicians with timely information on these revolutionary therapeutic approaches, the comprehensive review provides historical perspectives on the applications and clinical considerations of the immunotherapy. Here, we first outline the recent advances that have been made in the understanding of the various categories of immunotherapies in the treatment of hematologic malignancies. We further discuss the specific mechanisms of action, summarize the clinical trials and outcomes of immunotherapies in hematologic malignancies, as well as the adverse effects and toxicity management and then provide novel insights into challenges and future directions.

Modulation of Radiation Doses and Chimeric Antigen Receptor T Cells: A Promising New Weapon in Solid Tumors-A Narrative Review

Tumor behavior is determined by its interaction with the tumor microenvironment (TME). Chimeric antigen receptor (CART) cell therapy represents a new form of cellular immunotherapy (IT). Immune cells present a different sensitivity to radiation therapy (RT). RT can affect tumor cells both modifying the TME and inducing DNA damage, with different effects depending on the low and high doses delivered, and can favor the expression of CART cells. CART cells are patients' T cells genetically engineered to recognize surface structure and to eradicate cancer cells. High-dose radiation therapy (HDRT, >10-20 Gy/fractions) converts immunologically "cold" tumors into "hot" ones by inducing necrosis and massive inflammation and death. LDRT (low-dose radiation therapy, >5-10 Gy/fractions) increases the expansion of CART cells and leads to non-immunogenetic death. An innovative approach, defined as the LATTICE technique, combines a high dose in higher FDG- uptake areas and a low dose to the tumor periphery. The association of RT and immune checkpoint inhibitors increases tumor immunogenicity and immune response both in irradiated and non-irradiated sites. The aim of this narrative review is to clarify the knowledge, to date, on CART cell therapy and its possible association with radiation therapy in solid tumors.

Two cases of severe pulmonary toxicity from highly active mesothelin-directed CAR T cells

Multiple clinical studies have treated mesothelin (MSLN)-positive solid tumors by administering MSLN-directed chimeric antigen receptor (CAR) T cells. Although these products are generally safe, efficacy is limited. Therefore, we generated and characterized a potent, fully human anti-MSLN CAR. In a phase 1 dose-escalation study of patients with solid tumors, we observed two cases of severe pulmonary toxicity following intravenous infusion of this product in the high-dose cohort (1-3 × 108 T cells per m2). Both patients demonstrated progressive hypoxemia within 48 h of infusion with clinical and laboratory findings consistent with cytokine release syndrome. One patient ultimately progressed to grade 5 respiratory failure. An autopsy revealed acute lung injury, extensive T cell infiltration, and accumulation of CAR T cells in the lungs. RNA and protein detection techniques confirmed low levels of MSLN expression by benign pulmonary epithelial cells in affected lung and lung samples obtained from other inflammatory or fibrotic conditions, indicating that pulmonary pneumocyte and not pleural expression of mesothelin may lead to dose-limiting toxicity. We suggest patient enrollment criteria and dosing regimens of MSLN-directed therapies consider the possibility of dynamic expression of mesothelin in benign lung with a special concern for patients with underlying inflammatory or fibrotic conditions.

Coronary vasospasm during infusion of CD-19 directed chimeric antigen receptor T-cell therapy: a case report

Background

Cardiovascular events have been reported to occur in one in five patients receiving chimeric antigen receptor T-cell (CAR-T) therapy. Commonly reported effects including cardiomyopathy, heart failure, myocardial infarction (MI), and arrhythmia. Here, we present a novel case of a patient who developed acute ST segment elevations during CAR-T cell infusion.

Case summary

A 76-year-old man with diffuse large B cell lymphoma was admitted for an investigational CD-19 directed, autologous CAR-T cell therapy. Less than 5 min into the CAR-T cell infusion, he developed severe chest pain, dyspnea, flushing, hypotension, and tachycardia. Electrocardiogram (EKG) showed inferior ST elevations and reciprocal lateral ST depressions. Emergent coronary angiography revealed mild non-obstructive coronary disease. ST segment changes and patient symptoms resolved after catheterization.

Discussion

Given the complete resolution of symptoms and EKG abnormalities in the context of non-obstructive coronary artery disease, this clinical presentation was thought to be most consistent with ST elevation MI due to coronary vasospasm. The mechanism of this vasospasm is as yet not understood and may be related to an anaphylactic reaction or a cardiotoxicity related to the cell therapy agent. As the use of CAR-T therapy continues to expand, there is a need to further characterize the full spectrum of its cardiotoxic effects.

Mechanisms of Resistance and Treatment of Relapse after CAR T-cell Therapy for Large B-cell Lymphoma and Multiple Myeloma

Although chimeric antigen receptor (CAR) T cell therapy (CAR-T) has altered the treatment landscape for relapsed/refractory B cell malignancies and multiple myeloma, only a minority of patients attain long-term disease remission. The underlying reasons for CAR-T resistance are multifaceted and can be broadly divided into host-related, tumor-intrinsic, microenvironmental and macroenvironmental, and CAR-T-related factors. Emerging host-related determinants of response to CAR-T relate to gut microbiome composition, intact hematopoietic function, body composition, and physical reserve. Emerging tumor-intrinsic resistance mechanisms include complex genomic alterations and mutations to immunomodulatory genes. Furthermore, the extent of systemic inflammation prior to CAR-T is a potent biomarker of response and reflects a proinflammatory tumor micromilieu characterized by infiltration of myeloid-derived suppressor cells and regulatory T cell populations. The tumor and its surrounding micromilieu also can shape the response of the host to CAR-T infusion and the subsequent expansion and persistence of CAR T cells, a prerequisite for efficient eradication of tumor cells. Here, focusing on both large B cell lymphoma and multiple myeloma, we review resistance mechanisms, explore therapeutic avenues to overcome resistance to CAR-T, and discuss the management of patients who relapse after CAR-T.

Safety and clinical activity of autologous RNA chimeric antigen receptor T-cell therapy in myasthenia gravis (MG-001): a prospective, multicentre, open-label, non-randomised phase 1b/2a study

BACKGROUND

Chimeric antigen receptor (CAR) T cells are highly effective in treating haematological malignancies, but associated toxicities and the need for lymphodepletion limit their use in people with autoimmune disease. To explore the use of CAR T cells for the treatment of people with autoimmune disease, and to improve their safety, we engineered them with RNA (rCAR-T)-rather than the conventional DNA approach-to target B-cell maturation antigen (BCMA) expressed on plasma cells. To test the suitability of our approach, we used rCAR-T to treat individuals with myasthenia gravis, a prototypical autoantibody disease mediated partly by pathogenic plasma cells.

METHODS

MG-001 was a prospective, multicentre, open-label, phase 1b/2a study of Descartes-08, an autologous anti-BCMA rCAR-T therapy, in adults (ie, aged ≥18 years) with generalised myasthenia gravis and a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 6 or higher. The study was done at eight sites (ie, academic medical centres or community neurology clinics) in the USA. Lymphodepletion chemotherapy was not used. In part 1 (phase 1b), participants with Myasthenia Gravis Foundation of America (MGFA) disease class III-IV generalised myasthenia gravis received three ascending doses of Descartes-08 to determine a maximum tolerated dose. In part 2 (phase 2a), participants with generalised myasthenia gravis with MGFA disease class II-IV received six doses at the maximum tolerated dose in an outpatient setting. The primary objective was to establish safety and tolerability of Descartes-08; secondary objectives were to assess myasthenia gravis disease severity and biomarkers in participants who received Descartes-08. This trial is registered with clinicaltrials.gov, NCT04146051.

FINDINGS

We recruited 16 individuals for screening between Jan 7, 2020 and Aug 3, 2022. 14 participants were enrolled (n=3 in part 1, n=11 in part 2). Ten participants were women and four were men. Two individuals did not qualify due to low baseline MG-ADL score (n=1) or lack of generalised disease (n=1). Median follow-up in part 2 was 5 months (range 3-9 months). There was no dose-limiting toxicity, cytokine release syndrome, or neurotoxicity. Common adverse events were headache (six of 14 participants), nausea (five of 14), vomiting (three of 14), and fever (four of 14), which resolved within 24 h of infusion. Fevers were not associated with increased markers of cytokine release syndrome (IL-6, IL-2, and TNF). Mean improvements from baseline to week 12 were -6 (95% CI -9 to -3) for MG-ADL score, -7 (-11 to -3) for Quantitative Myasthenia Gravis score, -14 (-19 to -9) for Myasthenia Gravis Composite score, and -9 (-15 to -3) for Myasthenia Gravis Quality of Life 15-revised score.

INTERPRETATION

In this first study of an rCAR-T therapy in individuals with an autoimmune disease, Descartes-08 appeared to be safe and was well tolerated. Descartes-08 infusions were followed by clinically meaningful decreases on myasthenia gravis severity scales at up to 9 months of follow-up. rCAR-T therapy warrants further investigation as a potential new treatment approach for individuals with myasthenia gravis and other autoimmune diseases.

FUNDING

Cartesian Therapeutics and National Institute of Neurological Disorders and Stroke of the National Institutes of Health.

Current and potential roles of immuno-PET/-SPECT in CAR T-cell therapy

Chimeric antigen receptor (CAR) T-cell therapies have evolved as breakthrough treatment options for the management of hematological malignancies and are also being developed as therapeutics for solid tumors. However, despite the impressive patient responses from CD19-directed CAR T-cell therapies, ~ 40%-60% of these patients' cancers eventually relapse, with variable prognosis. Such relapses may occur due to a combination of molecular resistance mechanisms, including antigen loss or mutations, T-cell exhaustion, and progression of the immunosuppressive tumor microenvironment. This class of therapeutics is also associated with certain unique toxicities, such as cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, and other "on-target, off-tumor" toxicities, as well as anaphylactic effects. Furthermore, manufacturing limitations and challenges associated with solid tumor infiltration have delayed extensive applications. The molecular imaging modalities of immunological positron emission tomography and single-photon emission computed tomography (immuno-PET/-SPECT) offer a target-specific and highly sensitive, quantitative, non-invasive platform for longitudinal detection of dynamic variations in target antigen expression in the body. Leveraging these imaging strategies as guidance tools for use with CAR T-cell therapies may enable the timely identification of resistance mechanisms and/or toxic events when they occur, permitting effective therapeutic interventions. In addition, the utilization of these approaches in tracking the CAR T-cell pharmacokinetics during product development and optimization may help to assess their efficacy and accordingly to predict treatment outcomes. In this review, we focus on current challenges and potential opportunities in the application of immuno-PET/-SPECT imaging strategies to address the challenges encountered with CAR T-cell therapies.

mRNA-based cancer therapeutics

Due to the fact that mRNA technology allows the production of diverse vaccines and treatments in a shorter time frame and with reduced expense compared to conventional approaches, there has been a surge in the use of mRNA-based therapeutics in recent years. With the aim of encoding tumour antigens for cancer vaccines, cytokines for immunotherapy, tumour suppressors to inhibit tumour development, chimeric antigen receptors for engineered T cell therapy or genome-editing proteins for gene therapy, many of these therapeutics have shown promising efficacy in preclinical studies, and some have even entered clinical trials. Given the evidence supporting the effectiveness and safety of clinically approved mRNA vaccines, coupled with growing interest in mRNA-based therapeutics, mRNA technology is poised to become one of the major pillars in cancer drug development. In this Review, we present in vitro transcribed mRNA-based therapeutics for cancer treatment, including the characteristics of the various types of synthetic mRNA, the packaging systems for efficient mRNA delivery, preclinical and clinical studies, current challenges and future prospects in the field. We anticipate the translation of promising mRNA-based treatments into clinical applications, to ultimately benefit patients.

CAR T-Cell Therapy for Cancer: Latest Updates and Challenges, with a Focus on B-Lymphoid Malignancies and Selected Solid Tumours

Although exponential progress in treating advanced malignancy has been made in the modern era with immune checkpoint blockade, survival outcomes remain suboptimal. Cellular immunotherapy, such as chimeric antigen receptor T cells, has the potential to improve this. CAR T cells combine the antigen specificity of a monoclonal antibody with the cytotoxic 'power' of T-lymphocytes through expression of a transgene encoding the scFv domain, CD3 activation molecule, and co-stimulatory domains. Although, very rarely, fatal cytokine-release syndrome may occur, CAR T-cell therapy gives patients with refractory CD19-positive B-lymphoid malignancies an important further therapeutic option. However, low-level expression of epithelial tumour-associated-antigens on non-malignant cells makes the application of CAR T-cell technology to common solid cancers challenging, as does the potentially limited ability of CAR T cells to traffic outside the blood/lymphoid microenvironment into metastatic lesions. Despite this, in advanced neuroblastoma refractory to standard therapy, 60% long-term overall survival and an objective response in 63% was achieved with anti GD2-specific CAR T cells.