Safety and stability of retrovirally transduced chimeric antigen receptor T cells

Role of cell-based therapies in digestive disorders: Obstacles and opportunities

Stem cell-based therapies have emerged as a promising frontier in the treatment of gastrointestinal disorders, offering potential solutions for challenges posed by conventional treatments. This review comprehensively examines recent advancements in cell-based therapeutic strategies, particularly focusing on stem cell applications, immunotherapy, and cellular therapies for digestive diseases. It highlights the successful differentiation of enteric neural progenitors from pluripotent stem cells and their application in animal models, such as Hirschsprung disease. Furthermore, the review evaluates clinical trials and experimental studies demonstrating the potential of stem cells in regenerating damaged tissues, modulating immune responses, and promoting healing in conditions like Crohn's disease and liver failure. By addressing challenges, such as scalability, immunogenicity, and ethical considerations, the review underscores the translational opportunities and obstacles in realizing the clinical potential of these therapies. Concluding with an emphasis on future directions, the study provides insights into optimizing therapeutic efficacy and fostering innovations in personalized medicine for digestive disorders.

Broadly neutralizing antibody-derived CAR-T cells reduce viral reservoir in HIV-1-infected individuals

BACKGROUND

Chimeric antigen receptor (CAR)-modified T cells have emerged as a novel approach to treat malignant tumors. This strategy has also been proposed for the treatment of HIV-1 infection. We have developed a broadly neutralizing antibody (bNAb)-derived CAR-T cell therapy which can exerted specific cytotoxic activity against HIV-1-infected cells.

METHODS

We conducted an open-label trial of the safety, side-effect profile, pharmacokinetic properties, and antiviral activity of bNAb-derived CAR-T cell therapy in HIV-1-infected individuals who were undergoing analytical interruption of antiretroviral therapy (ART).

RESULTS

A total of 14 participants completed only a single administration of bNAb-derived CAR-T cells. CAR-T administration was safe and well tolerated. Six participants discontinued ART, and viremia rebound occurred in all of them, with a 5.3-week median time. Notably, the cell-associated viral RNA and intact proviruses decreased significantly after CAR-T treatment. Analyses of HIV-1 variants before or after CAR-T administration suggested that CAR-T cells exerted pressure on rebound viruses, resulting in a selection of viruses with less diversity and mutations against CAR-T-mediated cytotoxicity.

CONCLUSIONS

No safety concerns were identified with adoptive transfer of bNAb-derived CAR-T cells. They reduced viral reservoir. All the rebounds were due to preexisting or emergence of viral escape mutations.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT03240328.

FUNDING

Ministry of Science and Technology of China, National Natural Science Foundation of China, and Department of Science and Technology of Guangdong Province.

Chimeric antigen receptor T-cell therapy for HIV cure

PURPOSE OF REVIEW

Cell-based immunotherapies have made enormous progress over the last decade with the approval of several anti-CD19-chimeric antigen receptor (CAR)-T cell therapies for haemato-oncological diseases. CARs are synthetic receptors comprising an antigen-specific extracellular domain fused to a hinge, transmembrane and intracellular signalling domains. The success obtained with CD19 CAR-T cells rekindled interest in using CAR-T cells to treat HIV seropositive patients. The purpose of this review is to discuss historical and recent developments of anti-HIV CARs.

RECENT FINDINGS

Since the first description of CD4+-based CARs in the early 90s, new generations of anti-HIV CARs were developed. They target the hetero-trimeric glycoprotein gp120/gp41 and consist of either a CD4+ extracellular domain or a VH/VL segment derived from broadly neutralizing antibodies. Recent efforts were employed in multiplexing CAR specificities, intracellular signalling domains and T cells resistance to HIV.

SUMMARY

Several new-anti HIV CAR-T cells were successfully tested in preclinical mice models and are now waiting to be evaluated in clinical trials. One of the key parameters to successfully using CAR-T cells in HIV treatment will depend on their capacity to control the HIV reservoir without causing off-targeting activities.

Dual CD4-based CAR T cells with distinct costimulatory domains mitigate HIV pathogenesis in vivo

An effective strategy to cure HIV will likely require a potent and sustained antiviral T cell response. Here we explored the utility of chimeric antigen receptor (CAR) T cells, expressing the CD4 ectodomain to confer specificity for the HIV envelope, to mitigate HIV-induced pathogenesis in bone marrow, liver, thymus (BLT) humanized mice. CAR T cells expressing the 4-1BB/CD3-ζ endodomain were insufficient to prevent viral rebound and CD4⁺ T cell loss after the discontinuation of antiretroviral therapy. Through iterative improvements to the CAR T cell product, we developed Dual-CAR T cells that simultaneously expressed both 4-1BB/CD3-ζ and CD28/CD3-ζ endodomains. Dual-CAR T cells exhibited expansion kinetics that exceeded 4-1BB-, CD28- and third-generation costimulated CAR T cells, elicited effector functions equivalent to CD28-costimulated CAR T cells and prevented HIV-induced CD4⁺ T cell loss despite persistent viremia. Moreover, when Dual-CAR T cells were protected from HIV infection through expression of the C34-CXCR4 fusion inhibitor, these cells significantly reduced acute-phase viremia, as well as accelerated HIV suppression in the presence of antiretroviral therapy and reduced tissue viral burden. Collectively, these studies demonstrate the enhanced therapeutic potency of a novel Dual-CAR T cell product with the potential to effectively treat HIV infection.

CAR T cells: Living HIV drugs

Human immunodeficiency virus type 1 (HIV-1), the virus that causes AIDS (acquired immunodeficiency syndrome), is a major global public health issue. Although the advent of combined antiretroviral therapy (ART) has made significant progress in inhibiting HIV replication in patients, HIV-infected cells remain the principal cellular reservoir of HIV, this allows HIV to rebound immediately upon stopping ART, which is considered the major obstacle to curing HIV infection. Chimeric antigen receptor (CAR) cell therapy has provided new opportunities for HIV treatment. Engineering T cells or hematopoietic stem cells (HSCs) to generate CAR T cells is a rapidly growing approach to develop an efficient immune cell to fight HIV. Herein, we review preclinical and clinical data available for the development of CAR T cells. Further, the advantages and disadvantages of clinical application of anti-HIV CAR T cells will be discussed.

Use of Chimeric Antigen Receptor T Cell Therapy in Clinical Practice for Relapsed/Refractory Aggressive B Cell Non-Hodgkin Lymphoma: An Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy

Axicabtagene ciloleucel (YESCARTA; Kite Pharma, a Gilead Company, Los Angeles CA) and tisagenlecleucel (KYMRIAH; Novartis Pharmaceuticals Corp., Basel, Switzerland) are two CD19-directed chimeric antigen receptor (CAR) T cell products currently approved by the US Food and Drug Administration; the European Medicines Agency; Health Canada; Ministry of Health, Labor and Welfare (Japan); and Therapeutic Goods Administration (Australia) for treatment of specific subtypes of relapsed/refractory aggressive B cell non-Hodgkin lymphoma (NHL). Although this approval has been transformative in the use of cellular immunotherapy in lymphoma, there are concerns regarding appropriate use of this novel therapy and of short- and long-term toxicities. To address these issues, representatives of the American Society of Transplantation and Cellular Therapy convened to recognize and address key issues surrounding the clinical application of CD19 CAR T cell therapy in B cell lymphomas, in collaboration with worldwide experts. The aim of this article is to provide consensus opinion from experts in the fields of hematopoietic cell transplantation, cellular immunotherapy, and lymphoma regarding key clinical questions pertinent to the use of CD19 CAR T cell products for the treatment of NHL. As the clinical practice using CAR T cells grows worldwide, we anticipate that this guidance will be relevant for hematology/oncology physicians who care for patients with lymphomas.

Development of CAR-T cells for long-term eradication and surveillance of HIV-1 reservoir

Human immunodeficiency virus type 1 (HIV-1) reservoir is a pool of latently infected cells harboring replication-competent proviral DNA that limits antiretroviral therapy. Suppression of HIV-1 by combination antiretroviral therapy (cART) delays progression of the disease but does not eliminate the viral reservoir, necessitating lifetime daily administration of antiretroviral drugs. To achieve durable suppression of viremia without daily therapy, various strategies have been developed, including long-acting antiretroviral drugs (LA-ARVs), broadly neutralizing antibodies (bNAbs), and chimeric antigen receptor T (CAR-T) cells. Here, we summarize and discuss recent breakthroughs in CAR-T cell therapies toward the eradication of HIV-1 reservoir. Although substantial challenges exist, CAR-T cell technology may serve as a promising strategy toward HIV-1 functional cure.

CRISPR therapeutic tools for complex genetic disorders and cancer (Review)

One of the fundamental discoveries in the field of biology is the ability to modulate the genome and to monitor the functional outputs derived from genomic alterations. In order to unravel new therapeutic options, scientists had initially focused on inducing genetic alterations in primary cells, in established cancer cell lines and mouse models using either RNA interference or cDNA overexpression or various programmable nucleases [zinc finger nucleases (ZNF), transcription activator-like effector nucleases (TALEN)]. Even though a huge volume of data was produced, its use was neither cheap nor accurate. Therefore, the clustered regularly interspaced short palindromic repeats (CRISPR) system was evidenced to be the next step in genome engineering tools. CRISPR-associated protein 9 (Cas9)-mediated genetic perturbation is simple, precise and highly efficient, empowering researchers to apply this method to immortalized cancerous cell lines, primary cells derived from mouse and human origins, xenografts, induced pluripotent stem cells, organoid cultures, as well as the generation of genetically engineered animal models. In this review, we assess the development of the CRISPR system and its therapeutic applications to a wide range of complex diseases (particularly distinct tumors), aiming at personalized therapy. Special emphasis is given to organoids and CRISPR screens in the design of innovative therapeutic approaches. Overall, the CRISPR system is regarded as an eminent genome engineering tool in therapeutics. We envision a new era in cancer biology during which the CRISPR-based genome engineering toolbox will serve as the fundamental conduit between the bench and the bedside; nonetheless, certain obstacles need to be addressed, such as the eradication of side-effects, maximization of efficiency, the assurance of delivery and the elimination of immunogenicity.

CAR-T cell therapy in gastrointestinal tumors and hepatic carcinoma: From bench to bedside

The chimeric antigen receptor (CAR) is a genetically engineered receptor that combines a scFv domain, which specifically recognizes the tumor-specific antigen, with T cell activation domains. CAR-T cell therapies have demonstrated tremendous efficacy against hematologic malignancies in many clinical trials. Recent studies have extended these efforts to the treatment of solid tumors. However, the outcomes of CAR-T cell therapy for solid tumors are not as remarkable as the outcomes have been for hematologic malignancies. A series of hurdles has arisen with respect to CAR-T cell-based immunotherapy, which needs to be overcome to target solid tumors. The major challenge for CAR-T cell therapy in solid tumors is the selection of the appropriate specific antigen to demarcate the tumor from normal tissue. In this review, we discuss the application of CAR-T cells to gastrointestinal and hepatic carcinomas in preclinical and clinical research. Furthermore, we analyze the usefulness of several specific markers in the study of gastrointestinal tumors and hepatic carcinoma.

T-cell therapies for HIV: Preclinical successes and current clinical strategies

Although antiretroviral therapy (ART) has been successful in controlling HIV infection, it does not provide a permanent cure, requires lifelong treatment, and HIV-positive individuals are left with social concerns such as stigma. The recent application of T cells to treat cancer and viral reactivations post-transplant offers a potential strategy to control HIV infection. It is known that naturally occurring HIV-specific T cells can inhibit HIV initially, but this response is not sustained in the majority of people living with HIV. Genetically modifying T cells to target HIV, resist infection, and persist in the immunosuppressive environment found in chronically infected HIV-positive individuals might provide a therapeutic solution for HIV. This review focuses on successful preclinical studies and current clinical strategies using T-cell therapy to control HIV infection and mediate a functional cure solution.

A Multidrug-resistant Engineered CAR T Cell for Allogeneic Combination Immunotherapy

The adoptive transfer of chimeric antigen receptor (CAR) T cell represents a highly promising strategy to fight against multiple cancers. The clinical outcome of such therapies is intimately linked to the ability of effector cells to engraft, proliferate, and specifically kill tumor cells within patients. When allogeneic CAR T-cell infusion is considered, host versus graft and graft versus host reactions must be avoided to prevent rejection of adoptively transferred cells, host tissue damages and to elicit significant antitumoral outcome. This work proposes to address these three requirements through the development of multidrug-resistant T cell receptor αβ-deficient CAR T cells. We demonstrate that these engineered T cells displayed efficient antitumor activity and proliferated in the presence of purine and pyrimidine nucleoside analogues, currently used in clinic as preconditioning lymphodepleting regimens. The absence of TCRαβ at their cell surface along with their purine nucleotide analogues-resistance properties could prevent their alloreactivity and enable them to resist to lymphodepleting regimens that may be required to avoid their ablation via HvG reaction. By providing a basic framework to develop a universal T cell compatible with allogeneic adoptive transfer, this work is laying the foundation stone of the large-scale utilization of CAR T-cell immunotherapies.

A serum mesothelin level is a prognostic indicator for patients with malignant mesothelioma in routine clinical practice

BACKGROUND

Malignant mesothelioma (MM) carries a poor prognosis and response rates to palliative chemotherapy remain low. Identifying patients with MM that are unlikely to respond to chemotherapy could prevent futile treatments and improve patient quality of life. Studies have suggested that soluble mesothelin is a potential biomarker for early diagnosis and prognosis of MM. We set out to explore the utility of serum mesothelin in routine clinical practice.

METHODS

We conducted a prospective exploratory study of serum mesothelin levels in 53 consecutive patients with MM at our institution between April 2009 and February 2011. Survival was assessed and analysed by mesothelin level as both continuous and categorical variables using Cox regression models. Differences in response rate between treatment groups were assessed by the Kruskal-Wallis Test.

RESULTS

All 53 patients, who had been given study information agreed to participate. The patients' median age was 69 (range 24-90). Median mesothelin level was 2.7 nM and this value was used to dichotomize categories: ≤2.7 nM (low) and >2.7 nM (high). The progression free survival (PFS) for low vs high mesothelin was 8.0 vs 5.1 months (HR 1.8, p-0.058). When mesothelin was accessed as a continuous variable for PFS the HR was 1.03 (95% CI: 1.01-1.06; p=0.013). The overall survival (OS) for low vs high mesothelin was 17.2 vs 11.3 months (HR 1.9, p=0.088). When mesothelin was assessed as a continuous variable for OS the HR was 1.02 (95% CI: 0.99 - 1.04; p=0.073). Thirty patients received chemotherapy of which 18 had a pre-chemotherapy serum mesothelin level. In these 18 patients, the pre-chemotherapy mesothelin level did not correlate with response.

CONCLUSIONS

A single random sample provides information about patient prognosis but does not predict treatment response. We suggest further prospective validation of mesothelin testing as a prognostic biomarker.

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

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