CARs in chronic lymphocytic leukemia -- ready to drive

The Application of CAR-T Cells in Haematological Malignancies

Chimeric antigen receptor (CAR)-T cells (CART) remain one of the most advanced and promising forms of adoptive T-cell immunotherapy. CART represent autologous, genetically engineered T lymphocytes expressing CAR, i.e. fusion proteins that combine components and features of T cells as well as antibodies providing their more effective and direct anti-tumour effect. The technology of CART construction is highly advanced in vitro and every element of their structure influence their mechanism of action in vivo. Patients with haematological malignancies are faced with the possibility of disease relapse after the implementation of conventional chemo-immunotherapy. Since the most preferable result of therapy is a partial or complete remission, cancer treatment regimens are constantly being improved and customized to individual patients. This individualization could be ensured by CART therapy. This paper characterized CART strategy in details in terms of their structure, generations, mechanism of action and published the results of clinical trials in haematological malignancies including acute lymphoblastic leukaemia, diffuse large B-cell lymphoma, chronic lymphocytic leukaemia and multiple myeloma.

Chimeric antigen receptor therapy in hematological malignancies: antigenic targets and their clinical research progress

Chimeric antigen receptor (CAR)-based immunotherapy has achieved dramatic success in the treatment of B cell malignancies, based on the summary of current research data, and has shown good potential in early phase cancer clinical trials. Modified constructs are being optimized to recognize and destroy tumor cells more effectively. By targeting the proper B-lineage-specific antigens such as CD19 and CD20, adoptive immunotherapy has demonstrated promising clinical results and already plays a role in the treatment of several lymphoid malignancies, which highlights the importance of target selection for other CAR therapies. The high efficacy of CAR-T cells has resulted in the approval of anti-CD19-directed CAR-T cells for the treatment of B cell malignancies. In this review, we focus on the basic structure and current clinical application of CAR-T cells, detail the research progress of CAR-T for different antigenic targets in hematological malignancies, and further discuss the current barriers and proposed solutions, investigating the possible mechanisms of recurrence of CAR-T cell therapy. A summary of the paper is also given to overview as the prospects for this therapy.

Managing Patients With TP53-Deficient Chronic Lymphocytic Leukemia

Patients with chronic lymphocytic leukemia (CLL) having a chromosomal loss on the short arm of chromosome 17 including the TP53 gene locus (17p deletion) and/or having mutations in TP53 have a short overall survival and, until recently, limited treatment options. The recent introduction of two novel substance classes, B-cell receptor inhibitors and BH3 mimetics, into CLL treatment has provided enormous clinical progress in this previously difficult-to-treat patient subgroup characterized by high risk for treatment failure with standard chemoimmunotherapy and rapid disease progression. Compounds now approved for the treatment of TP53-deficient CLL are the two B-cell receptor inhibitors ibrutinib and idelalisib and the BH3 mimetic venetoclax. All three compounds were approved on the basis of favorable response rates that, importantly, revealed no differences between TP53-competent and TP53-deficient CLL cases. Using these compounds, longer-lasting remissions in patients with TP53-deficient CLL could be demonstrated for the first time. Whether TP53 alterations will maintain their significance as adverse prognostic factors in treatment strategies involving novel compounds needs to be assessed. This review provides an overview of current treatment options for 17p-deleted/ TP53-mutated CLL, including those compounds that are already approved by the US Food and Drug Administration or are under advanced clinical investigation. Available clinical trial data are discussed, as is the use of novel targeted treatment options in the context of transplant strategies, and an algorithm for off-study treatment of 17p-deficient CLL is suggested.

[Advances in the treatment of chronic lymphocytic leukaemia]

Chronic lymphocytic leukemia (CLL), a proliferation of mature B cells, is one of the most prevalent haematological malignancies. Progress has been made in its treatment during the last few decades, and chemoimmunotherapy based on fludarabine, cyclophosphamide and rituximab is considered the treatment of choice for patients with standard-risk CLL and good performance status. However, due to the characterization of high-risk biological subgroups and its presentation in elderly patients and/or with comorbidities, targeted therapies, such as B-cell receptor inhibitors, have been developed and approved during the last few years. The current review examines traditional therapeutic strategies and focuses on new small molecules that already represent promising elements of the CLL treatment landscape.

Regulatory B lymphocyte functions should be considered in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by an abnormal expansion of mature B cells in the bone marrow and their accumulation in blood and secondary lymphoid organs. Tumor CLL cells share expression of various surface molecules with many subsets of B cells and have several common characteristics with regulatory B cells (B regs). However, the identification of B regs and their role in CLL remain elusive. The aim of this review is to summarize recent works regarding the regulatory and phenotypic characteristic of B regs and their associated effects on the immune system. It is also meant to highlight their potential importance with regards to the immunotherapeutic response.

An update on current and prospective immunotherapies for chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia. Combined agent chemotherapy is the current standard front-line treatment for physically fit patients with CLL. Use of chemotherapy can be complicated by significant toxicity, especially in patients with advanced age or comorbid conditions. Moreover, patients may relapse and become refractory to further chemotherapy. Immunotherapy targets the aberrant immunological processes in CLL without the toxicity of chemotherapy. Immunotherapeutic strategies can also be combined with chemotherapy to improve response rates in this incurable disease. In this review, we evaluate current and future immune-based options in the treatment of CLL.

Chimeric Antigen Receptors Modified T-Cells for Cancer Therapy

The genetic modification and characterization of T-cells with chimeric antigen receptors (CARs) allow functionally distinct T-cell subsets to recognize specific tumor cells. The incorporation of costimulatory molecules or cytokines can enable engineered T-cells to eliminate tumor cells. CARs are generated by fusing the antigen-binding region of a monoclonal antibody (mAb) or other ligand to membrane-spanning and intracellular-signaling domains. They have recently shown clinical benefit in patients treated with CD19-directed autologous T-cells. Recent successes suggest that the modification of T-cells with CARs could be a powerful approach for developing safe and effective cancer therapeutics. Here, we briefly review early studies, consider strategies to improve the therapeutic potential and safety, and discuss the challenges and future prospects for CAR T-cells in cancer therapy.

Promising therapies for the treatment of chronic lymphocytic leukemia

INTRODUCTION

The combination schedule of fludarabine, cyclophosphamide and rituximab is the gold standard of therapy for younger, physically fit chronic lymphocytic leukemia (CLL) patients; it allows achieving high and durable complete response rates. Although treatment outcome has considerably improved with chemo-immunotherapy, most patients eventually relapse and CLL is still incurable. Thus, newer and more rationally developed drugs are needed to improve CLL therapy, particularly in cases of relapsed/refractory disease.

AREAS COVERED

The authors review preclinical and clinical data regarding newer CLL agents, currently undergoing examination, such as: signal transduction and cyclin-dependent kinase inhibitors, immunomodulatory agents, B-cell lymphoma 2 inhibitors, next generation mAbs, heat shock protein 90 and histone deacetylase inhibitors, and chimeric antigen receptor T-cell therapy.

EXPERT OPINION

Newer compounds with different mechanisms of action, such as B-cell receptor signal transduction inhibitors, lenalidomide, next generation mAbs and several pro-apoptotic molecules, have shown efficacy in relapsed or refractory CLL patients. Several studies are under way to investigate the efficacy of combinations of these novel drugs. Hopefully, the combined use of these molecules in risk-adapted treatment strategies will change the therapeutic approach in the near future and will pave the way for a long-term control of CLL.

Novel agents in the treatment of chronic lymphocytic leukemia: a review about the future

Half of a century ago, physicians managing chronic lymphocytic leukemia (CLL) recognized some of its presenting features such as lymphocytosis, lymphadenopathy, and splenomegaly. Subsequently, an enhanced understanding of the disease mechanisms involved in CLL led to new, more targeted treatments. There is now a plethora of treatments available for CLL. In this review article we discuss in detail several of the novel agents that are being studied or approved for the treatment of CLL including: phosphatidylinositol 3-kinase inhibitors (idelalisib and IPI-145), Bruton tyrosine kinase inhibitors (ibrutinib), B cell lymphoma 2 inhibitors (ABT-263 and ABT-199), new anti-CD20 monoclonal antibodies (obinutuzumab), cyclin-dependent kinase inhibitors (flavopiridol and dinaciclib), immunomodulators (lenalidomide) and chimeric antigen receptor T-cell therapy.

Immunotherapy for chronic lymphocytic leukemia in the era of BTK inhibitors

Understanding the pathogenesis of CLL has uncovered a plethora of novel targets for human application of monoclonal antibodies, engineered T cells, or inhibitors of signal transduction pathways. The B-cell receptor signaling pathway is being actively explored as a therapeutic target in CLL. Ibrutinib, an inhibitor of Bruton's tyrosine kinase is showing impressive responses in heavily pre-treated high-risk CLL, whether alone or in combination with MoAbs or chemotherapy. Other key components of the BCR pathway, namely PI3K-δ, are also being targeted with novel therapies with promising results as well. Future trials would likely evaluate ibrutinib in the front-line setting. Moreover, improvements in allogeneic HCT mostly by continuing to reduce associated toxicity as well as incorporating cellular therapies such as autologous CLL tumor vaccines, among others, will continue to expand. This is also the case for the next generation of chimeric antigen receptor therapy for CLL once genetically modified T cells are available at broad scale and with improved efficacy. As our ability to further refine and integrate these therapies continues to improve, and we gain further knowledge from gene sequencing, we anticipate that treatment algorithms will continue to be revised to a more personalized approach to treat this disease with improved efficacy and devoid of unnecessary toxicity.

Adoptive immunotherapy for cancer or viruses

Adoptive immunotherapy, or the infusion of lymphocytes, is a promising approach for the treatment of cancer and certain chronic viral infections. The application of the principles of synthetic biology to enhance T cell function has resulted in substantial increases in clinical efficacy. The primary challenge to the field is to identify tumor-specific targets to avoid off-tumor, on-target toxicity. Given recent advances in efficacy in numerous pilot trials, the next steps in clinical development will require multicenter trials to establish adoptive immunotherapy as a mainstream technology.