Influencing factors and solution strategies of chimeric antigen receptor T-cell therapy(CAR–T)cell immunotherapy

Chimeric antigen receptor T-cesll therapy(CAR–T)has achieved groundbreaking advancements in clinical application,ushering in a new era for innovative cancer treatment.However,the challenges associated with implementing this novel targeted cell therapy are increasingly significant.Particularly in the clinical management of solid tumors,obstacles such as the immunosuppressive effects of the tumor microenvironment,limited local tumor infiltration capability of CAR–T cells,heterogeneity of tumor targeting antigens,uncertainties surrounding CAR–T quality,control,and clinical adverse reactions have contributed to increased drug resistance and decreased compliance in tumor therapy.These factors have significantly impeded the widespread adoption and utilization of this therapeutic approach.In this paper,we comprehensively analyze recent preclinical and clinical reports on CAR–T therapy while summarizing crucial factors influencing its efficacy.Furthermore,we aim to identify existing solution strategies and explore their current research status.Through this review article,our objective is to broaden perspectives for further exploration into CAR–T therapy strategies and their clinical applications.

Chimeric antigen receptor-engineered T-cell therapy for liver cancer

Background: Chimeric antigen receptor-engineered T-cell(CAR-T) therapy is a newly developed immunotherapy used in the treatment of cancers. Because CAR-T therapy has shown great success in treating CD19-positive hematological malignancies, its application has been explored in the treatment of solid tumors, such as liver cancer. In this review, we discuss the immune characteristics of liver cancer, the obstacles encountered during the application of CAR-T therapy, and preclinical and clinical progress in the use of CAR-T therapy in patients with liver cancer.Data sources: The data on CAR-T therapy related to liver cancers were collected by searching Pub Med and the Web of Science databases prior to December 2017 with the keywords "chimeric antigen receptor","CAR-T", "liver cancer", "hepatocellular carcinoma", and "solid tumor". Additional articles were identified by manual search of references found in the primary articles. The data for clinical trials were collected by searching Clinical Trials.gov.Results: The liver has a tolerogenic nature in the intrahepatic milieu and its tumor microenvironment significantly affects tumor progression. The obstacles that reduce the efficacy of CAR-T therapy in solid tumors include a lack of specific tumor antigens, limited trafficking and penetration of CAR-T cells to tumor sites, and an immunosuppressive tumor microenvironment. To overcome these obstacles, several strategies have emerged. In addition, several strategies have been developed to manage the side effects of CAR-T, including enhancing the selectivity of CARs and controlling CAR-T activity. To date, no clinical trials of CAR-T therapy against HCC have been completed. However, preclinical studies in vitro and in vivo have shown potent antitumor efficacy. Glypican-3, mucin-1, epithelial cell adhesion molecule, carcinoembryonic antigen, and other targets are currently being studied.Conclusions: The application of CAR-T therapy for liver cancer is just beginning to be explored and more research is needed. However, we are optimistic that CAR-T therapy will offer a new approach for the treatment of liver cancers in the future.

The human application of gene therapy to re-program T-cell specificity using chimeric antigen receptors

The adoptive transfer of T cells is a promising approach to treat cancers. Primary human T cells can be modified using viral and non-viral vectors to promote the specific targeting of cancer cells via the introduction of exogenous T-cell receptors(TCRs) or chimeric antigen receptors(CARs). This gene transfer displays the potential to increase the specificity and potency of the anticancer response while decreasing the systemic adverse effects that arise from conventional treatments that target both cancerous and healthy cells. This review highlights the generation of clinical-grade T cells expressing CARs for immunotherapy, the use of these cells to target B-cell malignancies and, particularly, the first clinical trials deploying the Sleeping Beauty gene transfer system, which engineers T cells to target CD19+ leukemia and non-Hodgkin's lymphoma.

Cytokine release syndrome complicated with rhabdomyolysis after chimeric antigen receptor T-cell therapy:A case report

BACKGROUND Chimeric antigen receptor T-Cell(CAR-T)therapy is an effective new treatment for hematologic malignancies.Cytokine release syndrome(CRS)and neurologic toxicity are main toxicities.CRS-induced rhabdomyolysis(RM)followed by CART therapy treatment has not been previously reported.CASE SUMMARY We report a case of a 22-year-old woman with relapsed acute lymphoblastic leukemia obtained sequential cluster of differentiation(CD)19 and CD22 CAR-T infusion.This patient experienced grade 3 CRS with RM,mild hypotension requiring intravenous fluids,and mild hypoxia and was managed effectively with the IL-6 receptor antagonist tocilizumab.This patient had no signs of immune effector cell-associated neurologic syndrome.Restaging scans 30 d postCAR-T therapy demonstrated a complete remission,and the symptoms of muscle weakness improved through rehabilitation.CONCLUSION Myalgia is an easily overlooked symptom of severe CRS after CAR-T therapy.It is necessary to monitor myoglobin levels when a patient presents with symptoms of myalgia or acute renal insufficiency.

Chidamide and sintilimab combination in diffuse large B-cell lymphoma progressing after chimeric antigen receptor T therapy

BACKGROUND Diffuse large B-cell lymphoma(DLBCL)is curable with first-line chemoimmunotherapy but patients with relapsed/refractory(R/R)DLBCL still face a poor prognosis.For patients with R/R DLBCL,the complete response rate to traditional next-line therapy is only 7%and the median overall survival is 6.3 mo.Recently,CD19-targeting chimeric antigen receptor T cells(CAR-T)have shown promise in clinical trials.However,approximately 50%of patients treated with CAR-T cells ultimately progress and few salvage therapies are effective.CASE SUMMARY Here,we report on 7 patients with R/R DLBCL whose disease progressed after CAR-T infusion.They received a PD-1 inhibitor(sintilimab)and a histone deacetylase inhibitor(chidamide).Five of the 7 patients tolerated the treatment without any serious adverse events.Two patients discontinued the treatment due to lung infection and rash.At the 20-mo follow-up,the median overall survival of these 7 patients was 6 mo.Of note,there were 2 complete response rates(CRs)and 2 partial response rates(PRs)during this novel therapy,with an overall response rate(ORR)of 57.1%,and one patient had a durable CR that lasted at least 20 mo.CONCLUSION In conclusion,chidamide combined with sintilimab may be a choice for DLBCL patients progressing after CD19-targeting CAR-T therapy.

T cells expressing a LMP1-specific chimeric antigen receptor mediate antitumor effects against LMP1-positive nasopharyngeal carcinoma cells in vitro and in vivo

T cells modified with chimeric antigen receptor are an attractive strategy to treat Epstein-Barr virus（EBV） associated malignancies.The EBV latent membrane protein 1（LMP1） is a 66-KD integral membrane protein encoded by EBV that consists of transmembrane-spanning loops.Previously,we have identified a functional signal chain variable fragment（scFv） that specifically recognizes LMP1 through phage library screening.Here,we constructed a LMP1 specific chimeric antigen receptor containing anti-LMP1 scFv,the CD28 signalling domain,and the CD3ζchain（HELA/CAR）.We tested its functional ability to target LMP1 positive nasopharyngeal carcinoma cells.HELA/CAR cells were efficiently generated using lentivirus vector encoding the LMP1-specific chimeric antigen receptor to infect activated human CD3＋ T cells.The HELA/CAR T cells displayed LMP1 specific cytolytic action and produced IFN-γ and IL-2 in response to nasopharyngeal carcinoma cells overexpressing LMP1.To demonstrate in vivo anti-tumor activity,we tested the HELA/CAR T cells in a xenograft model using an LMP1 overexpressing tumor.Intratumoral injection of anti-LMP1 HELA/CAR-T cells significantly reduced tumor growth in vivo.These results show that targeting LMP1 using HELA/CAR cells could represent an alternative therapeutic approach for patients with EBV-positive cancers.

Tumor neoantigens: Novel strategies for application of cancer immunotherapy

Neoantigen-targeted immunotherapy is a rapidly advancing field that holds great promise for treating cancer.The recognition of antigens by immune cells is a crucial step in tumor-specific killing,and neoantigens generated by mutations in cancer cells possess high immunogenicity and are selectively expressed in tumor cells,making them an attractive therapeutic target.Currently,neoantigens find utility in various domains,primarily in the realm of neoantigen vaccines such as DC vaccines,nucleic acid vaccines,and synthetic long peptide vaccines.Additionally,they hold promise in adoptive cell therapy,encompassing tumor-infiltrating cells,T cell receptors,and chimeric antigen receptors which are expressed by genetically modified T cells.In this review,we summarized recent progress in the clinical use of tumor vaccines and adoptive cell therapy targeting neoantigens,discussed the potential of neoantigen burden as an immune checkpoint in clinical settings.With the aid of state-of-the-art sequencing and bioinformatics technologies,together with significant advancements in artificial intelligence,we anticipated that neoantigens will be fully exploited for personalized tumor immunotherapy,from screening to clinical application.

Revolutionizing gastric cancer treatment:The potential of immunotherapy

Gastric cancer,a prevalent malignancy worldwide,ranks sixth in terms of frequency and third in fatality,causing over a million new cases and 769000 annual deaths.Predominant in Eastern Europe and Eastern Asia,risk factors include family medical history,dietary habits,tobacco use,Helicobacter pylori,and Epstein-Barr virus infections.Unfortunately,gastric cancer is often diagnosed at an advanced stage,leading to a grim prognosis,with a 5-year overall survival rate below 5%.Surgical intervention,particularly with D2 Lymphadenectomy,is the mainstay for early-stage cases but offers limited success.For advanced cases,the National Comprehensive Cancer Network recommends chemotherapy,radiation,and targeted therapy.Emerging immunotherapy presents promise,especially for unresectable or metastatic cases,with strategies like immune checkpoint inhibitors,tumor vaccines,adoptive immunotherapy,and nonspecific immunomodulators.In this Editorial,with regards to the article“Advances and key focus areas in gastric cancer immunotherapy:A comprehensive scientometric and clinical trial review”,we address the advances in the field of immunotherapy in gastric cancer and its future prospects.

Prevention of hepatitis B reactivation in patients with hematologic malignancies treated with novel systemic therapies:Who and Why?

The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown possibility.The indication of antiviral prophylaxis with nucleo(t)side analogue is given according to the risk of HBV reactivation of the prescribed therapy.Though the advent of new drugs is occurring in all the field of medicine,in the setting of hematologic malignancies the last few years have been characterized by several drug classes and innovative cellular treatment.As novel therapies,there are few data about the rate of HBV reactivation and the decision of starting or not an antiviral prophylaxis could be challenging.Moreover,patients are often treated with a combination of different drugs,so evaluating the actual role of these new therapies in increasing the risk of HBV reactivation is difficult.First results are now available,but further studies are still needed.Patients with chronic HBV infection[hepatitis B surface antigen(HBsAg)positive]are reasonably all treated.Past/resolved HBV patients(HBsAg negative)are the actual area of uncertainty where it could be difficult choosing between prophylaxis and pre-emptive strategy.

Chimeric antigen receptor-immune cells against solid tumors:Structures,mechanisms,recent advances,and future developments

The advent of chimeric antigen receptor(CAR)-T cell immunotherapies has led to breakthroughs in the treatment of hematological malignancies.However,their success in treating solid tumors has been limited.CAR-natural killer(NK)cells have several advantages over CAR-T cells because NK cells can be made from pre-existing cell lines or allogeneic NK cells with a mismatched major histocompatibility complex(MHC),which means they are more likely to become an"off-the-shelf"product.Moreover,they can kill cancer cells via CAR-dependent/independent pathways and have limited toxicity.Macrophages are the most malleable immune cells in the body.These cells can efficiently infiltrate into tumors and are present in large numbers in tumor microenvironments(TMEs).Importantly,CAR-macrophages(CAR-Ms)have recently yielded exciting preclinical results in several solid tumors.Nevertheless,CAR-T,CAR-NK,and CAR-M all have their own advantages and limitations.In this review,we systematically discuss the current status,progress,and the major hurdles of CAR-T cells,CAR-NK cells,and CAR-M as they relate to five aspects:CAR structure,therapeutic mechanisms,the latest research progress,current challenges and solutions,and comparison according to the existing research in order to provide a reasonable option for treating solid tumors in the future.

Prevention and management of hepatitis B virus reactivation in patients with hematological malignancies in the targeted therapy era

Hepatitis due to hepatitis B virus(HBV)reactivation can be serious and potentially fatal,but is preventable.HBV reactivation is most commonly reported in patients receiving chemotherapy,especially rituximab-containing therapy for hematological malignancies and those receiving stem cell transplantation.Patients with inactive and even resolved HBV infection still have persistence of HBV genomes in the liver.The expression of these silent genomes is controlled by the immune system.Suppression or ablation of immune cells,most importantly B cells,may lead to reactivation of seemingly resolved HBV infection.Thus,all patients with hematological malignancies receiving anticancer therapy should be screened for active or resolved HBV infection by blood tests for hepatitis B surface antigen(HBsAg)and antibody to hepatitis B core antigen.Patients found to be positive for HBsAg should be given prophylactic antiviral therapy.For patients with resolved HBV infection,there are two approaches.The first is pre-emptive therapy guided by serial HBV DNA monitoring,and treatment with antiviral therapy as soon as HBV DNA becomes detectable.The second approach is prophy-lactic antiviral therapy,particularly for patients receiving high-risk therapy,especially anti-CD20 monoclonal antibody or hematopoietic stem cell transplantation.Entecavir and tenofovir are the preferred antiviral choices.Many new effective therapies for hematological malignancies have been introduced in the past decade,for example,chimeric antigen receptor(CAR)-T cell therapy,novel monoclonal antibodies,bispecific antibody drug conjugates,and small molecule inhibitors,which may be associated with HBV reactivation.Although there is limited evidence to guide the optimal preventive measures,we recommend antivi-ral prophylaxis in HBsAg-positive patients receiving novel treatments,including Bruton’s tyrosine kinase inhibitors,B-cell lymphoma 2 inhibitors,and CAR-T cell therapy.Further studies are needed to determine the risk of HBV reactivation with these agents and the best prophylactic strategy.

ncreasing the safety and efficacy of chimeric antigen receptor T cell therapy

Chimeric antigen receptor （CAR） T cell therapy is a promising cancer treatment that has recently been undergoing rapid development. However, there are still some major challenges, including precise tumor targeting to avoid off-target or ＂on-target/off-tumor＂ toxicity, adequate T cell infiltration and migration to solid tumors and T cell proliferation and persistence across the physical and biochemical barriers of solid tumors. In this review, we focus on the primary challenges and strafegies to design safe and effective CAR T cells, including using novel cutting-edge technologies for CAR and vecfor designs to increase both the safety and efficacy, further T cell modification to overcome the tumorassociated immune suppression, and using gene editing technologies to generate universal CAR T cells. All these efforts promote the development and evolution of CAR T cell therapy and move toward our ultimate goal--curing cancer with high safety, high efficacy, and low cost.

Advancing chimeric antigen receptor T cel therapy with CRISPR/Cas9

The clustered regularly interspaced short palindromic repeats （CRISPR）/CRISPR-associated 9 （CRISPR/Casg） system, an RNA-guided DNA targeting technology, is triggering a revolution in the field of biology. CRISPR/ Cas9 has demonstrated great potential for genetic manipulation. In this review, we discuss the current development of CRISPR/Cas9 technologies for thera- peutic applications, especially chimeric antigen receptor （CAR） T cell-based adoptive immunotherapy. Different methods used to facilitate efficient CRISPR delivery and gene editing in T cells are compared. The potential of genetic manipulation using CRISPR/Cas9 system to generate universal CAR T cells and potent T cells that are resistant to exhaustion and inhibition is explored. We also address the safety concerns associated with the use of CRISPR/Cas9 gene editing and provide potential solutions and future directions of CRISPR application in the field of CAR T cell immunotherapy. As an integration-free gene insertion method, CRISPR/Cas9 holds great promise as an efficient gene knock-in platform. Given the tremendous progress that has been made in the past few years, we believe that the CRISPPJ Cas9 technology holds immense promise for advancing immunotherapy.

Evaluation and reflection on claudin 18.2 targeting therapy in advanced gastric cancer

Claudin 18.2(CLDN18.2)is a tight-junction protein.CLDN18.2-targeting strategy has cut a striking figure in CLDN18.2 positive patients with advanced gastric cancer.Zolbetuximab,the CLDN18.2 antibody,obtained a better clinical benefit in patients compared with the controlled.In phase II trials,combination treatment of epirubicin,oxaliplatin and capecitabine(EOX)+zolbetuximab achieved the optimal effects of overall survival which extended to 13.2 months with tolerable safety events,indicating its greater potential playing the second promising target in gastric cancer.This review will reveal the definitive clinical benefit CLDN18.2-targeting therapies have achieved and update the highlighting development(like chimeric antigen receptor T-cell immunotherapy)to CLDN18.2 positive patients.We then focus on 10 questions arisen from recent progress and anticipate to provide a future perspective for novel cancer treatment.

Chimeric antigen receptor- and natural killer cell receptor-engineered innate killer cells in cancer immunotherapy

Chimeric antigen receptor(CAR)-engineered T-cell(CAR-T)therapy has demonstrated impressive therapeutic efficacy against hematological malignancies,but multiple challenges have hindered its application,particularly for the eradication of solid tumors.Innate killer cells(IKCs),particularly NK cells,NKT cells,andγδT cells,employ specific antigen-independent innate tumor recognition and cytotoxic mechanisms that simultaneously display high antitumor efficacy and prevent tumor escape caused by antigen loss or modulation.IKCs are associated with a low risk of developing GVHD,thus offering new opportunities for allogeneic“off-the-shelf”cellular therapeutic products.The unique innate features,wide tumor recognition range,and potent antitumor functions of IKCs make them potentially excellent candidates for cancer immunotherapy,particularly serving as platforms for CAR development.In this review,we first provide a brief summary of the challenges hampering CAR-T-cell therapy applications and then discuss the latest CAR-NK-cell research,covering the advantages,applications,and clinical translation of CAR-and NK-cell receptor(NKR)-engineered IKCs.Advances in synthetic biology and the development of novel genetic engineering techniques,such as gene-editing and cellular reprogramming,will enable the further optimization of IKC-based anticancer therapies.

Engineered T Cell Therapies from a Drug Development Viewpoint

Cancer is one of the leading causes of death worldwide. Recent advances in cellular therapy have demonstrated that this platform has the potential to give patients with certain cancers a second chance at life. Unlike chemical compounds and proteins, cells are living, self-replicating drugs that can be engineered to possess exquisite specificity. For example, T cells can be genetically modified to express chimeric antigen receptors (CARs), endowing them with the capacity to recognize and kill tumor cells and form a memory pool that is ready to strike back against persisting malignant cells. Anti-CD19 chimeric antigen receptor T cells (CART19s) have demonstrated a remarkable degree of clinical efficacy for certain malignancies. The process of developing CART19 essentially follows the conventional “one gene, one drug, one disease” paradigm derived from Paul Ehrlich’s “magic bullet” concept. With major players within the pharmaceutical industry joining forces to commercialize this new category of “living drugs,” it is useful to use CART19 as an example to examine the similarities and differences in its development, compared with that of a conventional drug. In this way, we can assimilate existing knowledge and identify the most effective approach for advancing similar strategies. This article reviews the use of biomarker-based assays to guide the optimization of CAR constructs, preclinical studies, and the evaluation of clinical efficacy;adverse effects (AEs);and CART19 cellular kinetics. Advanced technologies and computational tools that enable the discovery of optimal targets, novel CAR binding domains, and biomarkers predicting clinical response and AEs are also discussed. We believe that the success of CART19 will lead to the development of other engineered T cell therapies in the same manner that the discovery of arsphenamine initiated the era of synthetic pharmaceuticals.

Anti-BCMA CAR-T Cell Therapy in Relapsed or Refractory Multiple Myeloma Patients with Impaired Renal Function

Anti-B cell maturation antigen(BCMA)chimeric antigen receptor(CAR)T-cell therapyis effective and well-tolerated for refractory or relapsed multiple myeloma(RRMM).The purposcof the present study was to analyze efficacy in RRMM patients with renal impairment treated byanti-BCMA CAR-T cell therapy.A total of 59 RRMM patients were selected,and divided intoimpaired renal function(lRF)group[basclinc cstimated giomerular filtration rate(eSFR)<90 m/min/1.73 m^2(n=18)]and normal renal function(NRF)group(baseline eGFR≥90 mL/min/1.73 m,n=41).For patients with IRF,eGFR at the 6th month post-CAR-T cells infusion was significantlyhigher than the baseline(P<0.05).The multivariate analysis showed that light chain type and beta-2 micro-globulin(bcta-2M)were associated factors with the decrease of serum creatinine.Medianprogression-free survival(PFS)in the NRF group and IRF group was 266 days and 181 daysrespectively.Overall survival(OS)in the NRF group and lRF group was 877 days and 238 daysrespectively.There was no significant difference in the objective response rate(ORR)between thelRF group and the NRF group.It is suggested that CAR-T cells therapy could improve the renalfunction during the treatment of RRMM.The renal function could be more significantly improvedin RRMM patients with light chain type than with other types.

CAR T Cell Therapy for Hematological Malignancies

As a rapidly progressing field in oncology,the adoptive transfer of T cells that have been genetically modified with chimeric antigen receptors(CARs)has shown striking efficacy in the management of hematological malignancies and has been reported in a number of clinical trials.of note,CAR T cell therapy has shown extraordinary potential,especially in relapsed/refractory patients.However,there are still challenges regarding the further development of this strategy,spanning from engineering and manufacturing issues,to limited applications,to accompanying toxicities.In this review,we will summarize the general knowledge of this novel method,including receptor composition,applications,adverse events and challenges.Additionally,we will propose several comprehensive recommendations.

Cancer stem cell-targeted chimeric antigen receptor(CAR)-T cell therapy: Challenges and prospects

Cancer stem cells(CSCs)with their self-renewal ability are accepted as cells which initiate tumors.CSCs are regarded as interesting targets for novel anticancer therapeutic agents because of their association with tumor recurrence and resistance to conventional therapies,including radiotherapy and chemotherapy.Chimeric antigen receptor(CAR)-T cells are engineered T cells which express an artificial receptor specific for tumor associated antigens(TAAs)by which they accurately target and kill cancer cells.In recent years,CAR-T cell therapy has shown more efficiency in cancer treatment,particularly regarding blood cancers.The expression of specific markers such as TAAs on CSCs in varied cancer types makes them as potent tools for CAR-T cell therapy.Here we review the CSC markers that have been previously targeted with CAR-T cells,as well as the CSC markers that may be used as possible targets for CAR-T cell therapy in the future.Furthermore,we will detail the most important obstacles against CART cell therapy and suggest solutions.

Novel cellular therapies for hepatobiliary malignancies

Background:The mortalities of hepatobiliary malignancies are high.With the failure of conventional chemotherapy and unsatisfactory outcome of molecular targeted drugs,immune-based therapy has become a new focus of research in hepatobiliary cancers treatment.Data sources:We performed a Pub Med search with relevant articles published up to May 2022 and the following keywords:cellular immunotherapy,hepatobiliary cancer,antigen receptor T cell therapy,and receptor-engineered T cell.Information of clinical trials was obtained from https://clinicaltrials.gov/.Results:Cell therapies for hepatobiliary malignancies are at early stage of development.The current review showed that cellular therapies are safe and feasible in patients.These findings provide an important platform for future lager scale clinical trials on immunotherapy in patients with hepatobiliary malignancies.Conclusions:With the continuous advances of cellular immunotherapy,the combination of cellular immunotherapy with surgery,chemotherapy and radiotherapy will be new therapeutic strategies for patients with hepatobiliary cancer.