Role of Immunotherapy in Targeting the Bone Marrow Microenvironment in Multiple Myeloma: An Evolving Therapeutic Strategy

Efficacy of CARVYKTI in CARTITUDE-4 versus other conventional treatment regimens for lenalidomide-refractory multiple myeloma using inverse probability of treatment weighting

Aim: The phase III randomized controlled trial (RCT) CARTITUDE-4 (NCT04181827) demonstrated superiority of CARVYKTI (ciltacabtagene autoleucel; cilta-cel) over daratumumab, pomalidomide and dexamethasone (DPd) and pomalidomide, bortezomib and dexamethasone (PVd) for relapsed/refractory multiple myeloma (RRMM) patients who have received one to three prior line(s) of therapy (LOT[s]) including an immunomodulatory agent and a proteasome inhibitor, and are refractory to lenalidomide. These analyses estimate the relative efficacy between cilta-cel and other common treatment regimens, for which no direct comparative evidence is available. Materials & methods: Patient data were available from the CARTITUDE-4, CASTOR, CANDOR and APOLLO RCTs. Imbalances between cohorts on key patient characteristics were adjusted for using inverse probability of treatment weighting (IPTW). Relative efficacies were estimated with response rate ratios (RRs) and 95% confidence intervals (CIs) for overall response rate (ORR), very good partial response or better rate (≥VGPR) and complete response or better rate (≥CR), and with hazard ratios (HRs) and 95% CIs for progression-free survival (PFS). Sensitivity analyses using different analytical methods and additional covariates were explored. Results: Key characteristics were well balanced across cohorts after IPTW. Cilta-cel showed statistically significant benefit in PFS (HRs: 0.11-0.51), ≥VGPR (RRs: 1.51-5.13) and ≥CR (RRs: 2.90-35.24) versus all comparators, and statistically significant improvements in ORR over most comparator regimens (RRs: 1.22-1.90). Results were consistent across sensitivity analyses. Conclusion: Cilta-cel demonstrated benefit over other common treatment regimens, highlighting its potential to become a new standard of care option for lenalidomide-refractory RRMM patients with one to three prior LOT(s). These comparisons help to demonstrate the improved efficacy of cilta-cel in countries where the standard of care may differ from DPd/PVd.

A neutrophil extracellular trap-related risk score predicts prognosis and characterizes the tumor microenvironment in multiple myeloma

Multiple myeloma (MM) is a distinguished hematologic malignancy, with existing studies elucidating its interaction with neutrophil extracellular traps (NETs), which may potentially facilitate tumor growth. However, systematic investigations into the role of NETs in MM remain limited. Utilizing the single-cell dataset GSE223060, we discerned active NET cell subgroups, namely neutrophils, monocytes, and macrophages. A transcriptional trajectory was subsequently constructed to comprehend the progression of MM. Following this, an analysis of cellular communication in MM was conducted with a particular emphasis on neutrophils, revealing an augmentation in interactions albeit with diminished strength, alongside abnormal communication links between neutrophils and NK cells within MM samples. Through the intersection of differentially expressed genes (DEGs) between NET active/inactive cells and MM versus healthy samples, a total of 316 genes were identified. This led to the development of a 13-gene risk model for prognostic prediction based on overall survival, utilizing transcriptomics dataset GSE136337. The high-risk group manifested altered immune infiltration and heightened sensitivity to chemotherapy. A constructed nomogram for predicting survival probabilities demonstrated encouraging AUCs for 1, 3, and 5-year survival predictions. Collectively, our findings unveil a novel NET-related prognostic signature for MM, thereby providing a potential avenue for therapeutic exploration.

The role of bone marrow microenvironment on CAR-T efficacy in haematologic malignancies

In recent years, chimeric antigen receptor-T (CAR-T) cell therapy has emerged as a novel immunotherapy method. It has shown significant therapeutic efficacy in the treatment of haematological B cell malignancies. In particular, the CAR-T therapy targeting CD19 has yielded unprecedented efficacy for acute B-lymphocytic leukaemia (B-ALL) and non-Hodgkin's lymphoma (NHL). In haematologic malignancies, tumour stem cells are more prone to stay in the regulatory bone marrow (BM) microenvironment (called niches), which provides a protective environment against immune attack. However, how the BM microenvironment affects the anti-tumour efficacy of CAR-T cells and its underlying mechanism is worthy of attention. In this review, we discuss the role of the BM microenvironment on the efficacy of CAR-T in haematological malignancies and propose corresponding strategies to enhance the anti-tumour activity of CAR-T therapy.

Treating Multiple Myeloma in the Context of the Bone Marrow Microenvironment

The treatment landscape of multiple myeloma (MM) has evolved considerably with the FDA-approval of at least 15 drugs over the past two decades. Together with the use of autologous stem cell transplantation, these novel therapies have resulted in significant survival benefit for patients with MM. In particular, our improved understanding of the BM and immune microenvironment has led to the development of highly effective immunotherapies that have demonstrated unprecedented response rates even in the multiple refractory disease setting. However, MM remains challenging to treat especially in a high-risk setting. A key mediator of therapeutic resistance in MM is the bone marrow (BM) microenvironment; a deeper understanding is necessary to facilitate the development of therapies that target MM in the context of the BM milieu to elicit deeper and more durable responses with the ultimate goal of long-term control or a cure of MM. In this review, we discuss our current understanding of the role the BM microenvironment plays in MM pathogenesis, with a focus on its immunosuppressive nature. We also review FDA-approved immunotherapies currently in clinical use and highlight promising immunotherapeutic approaches on the horizon.

Immunotherapy for the treatment of multiple myeloma

Despite advances in treatment for multiple myeloma, the majority of patients ultimately develop relapsed disease marked by immune evasion and resistance to standard therapy. Immunotherapy has emerged as a powerful tool for tumor-directed cytotoxicity with the unique potential to induce immune memory to reduce the risk of relapse. Understanding the specific mechanisms of immune dysregulation and dysfunction in advanced myeloma is critical to the development of further therapies that produce a durable response. Adoptive cellular therapy, most strikingly CAR T cell therapy, has demonstrated dramatic responses in the setting of refractory disease. Understanding the factors that contribute to immune evasion and the mechanisms of response and resistance to therapy will be critical to developing the next generation of adoptive cellular therapies, informing novel combination therapy, and determining the optimal time to incorporate immune therapy in the treatment of myeloma.

Deciphering mechanisms of immune escape to inform immunotherapeutic strategies in multiple myeloma

Multiple myeloma is an incurable cancer characterized by the uncontrolled growth of malignant plasma cells nurtured within a permissive bone marrow microenvironment. While patients mount numerous adaptive immune responses directed against their disease, emerging data demonstrate that tumor intrinsic and extrinsic mechanisms allow myeloma cells to subvert host immunosurveillance and resist current therapeutic strategies. Myeloma downregulates antigens recognized by cellular immunity and modulates the bone marrow microenvironment to promote uncontrolled tumor proliferation, apoptotic resistance, and further hamper anti-tumor immunity. Additional resistance often develops after an initial clinical response to small molecules, immune-targeting antibodies, immune checkpoint blockade or cellular immunotherapy. Profound quantitative and qualitative dysfunction of numerous immune effector cell types that confer anti-myeloma immunity further supports myelomagenesis, disease progression and the emergence of drug resistance. Identification of tumor intrinsic and extrinsic resistance mechanisms may direct the design of rationally-designed drug combinations that prevent or overcome drug resistance to improve patient survival. Here, we summarize various mechanisms of immune escape as a means to inform novel strategies that may restore and improve host anti-myeloma immunity.

Evolving cancer-niche interactions and therapeutic targets during bone metastasis

Many cancer types metastasize to bone. This propensity may be a product of genetic traits of the primary tumour in some cancers. Upon arrival, cancer cells establish interactions with various bone-resident cells during the process of colonization. These interactions, to a large degree, dictate cancer cell fates at multiple steps of the metastatic cascade, from single cells to overt metastases. The bone microenvironment may even influence cancer cells to subsequently spread to multiple other organs. Therefore, it is imperative to spatiotemporally delineate the evolving cancer-bone crosstalk during bone colonization. In this Review, we provide a summary of the bone microenvironment and its impact on bone metastasis. On the basis of the microscopic anatomy, we tentatively define a roadmap of the journey of cancer cells through bone relative to various microenvironment components, including the potential of bone to function as a launch pad for secondary metastasis. Finally, we examine common and distinct features of bone metastasis from various cancer types. Our goal is to stimulate future studies leading to the development of a broader scope of potent therapies.

Cell-based therapeutics for the treatment of hematologic diseases inside the bone marrow

Cell-based therapies could overcome the limitations of traditional drugs for the treatment of refractory diseases. Cell exchange between the bone marrow and blood is bidirectional. Several kinds of cells in the blood have the capability to enter the bone marrow by interacting with sinusoidal cells under specific physiological or pathological conditions. These cells are the potential living therapeutics or delivery vehicles to treat or prevent bone marrow-related hematologic diseases. In this review, we summarized the in vivo molecular mechanisms and kinetics of these cells in entering the bone marrow. The advances in the fabrication of living cell drugs and the strategies to design cell-based carriers into the bone marrow were discussed. The latest studies on how to use blood cells as living drugs or as drug carriers to improve therapeutic outcomes of hematologic diseases inside the bone marrow were highlighted.

Chimeric antigen receptor T-cells (CARs) in cancer treatment

BACKGROUND

Cancer is one of the leading causes of death worldwide. Chemotherapy, radiation therapy, and stem cell transplantation were the main cancer treatment approaches for several years but due to their limited effectiveness, there was a constant search for new therapeutic approaches. Cancer immunotherapy that utilizes and enhances the normal capacity of the patient's immune system was used to fight against cancer. Genetically engineered T-cells that express chimeric antigen receptors (CARs) showed remarkable anti-tumor activity against hematologic malignancies and is now being investigated in a variety of solid tumors. The use of this therapy in the last few years has been successful, achieving a great success in improving the quality of life and prolonging the survival time of patients with a reduction in remission rates. However, many challenges still need to be resolved in order for this technology to gain widespread adoption. <P> Objective: This review summarizes various experimental approaches towards the use of CAR T-cells in hematologic malignancies and solid tumors. <P> Conclusion: Finally, we address the challenges posed by CAR T-cells and discuss strategies for improving the performance of these T cells in fighting cancers.

Any closer to successful therapy of multiple myeloma? CAR-T cell is a good reason for optimism

Despite many recent advances on cancer novel therapies, researchers have yet a long way to cure cancer. They have to deal with tough challenges before they can reach success. Nonetheless, it seems that recently developed immunotherapy-based therapy approaches such as adoptive cell transfer (ACT) have emerged as a promising therapeutic strategy against various kinds of tumors even the cancers in the blood (liquid cancers). The hematological (liquid) cancers are hard to be targeted by usual cancer therapies, for they do not form localized solid tumors. Until recently, two types of ACTs have been developed and introduced; tumor-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR)-T cells which the latter is the subject of our discussion. It is interesting about engineered CAR-T cells that they are genetically endowed with unique cancer-specific characteristics, so they can use the potency of the host immune system to fight against either solid or liquid cancers. Multiple myeloma (MM) or simply referred to as myeloma is a type of hematological malignancy that affects the plasma cells. The cancerous plasma cells produce immunoglobulins (antibodies) uncontrollably which consequently damage the tissues and organs and break the immune system function. Although the last few years have seen significant progressions in the treatment of MM, still a complete remission remains unconvincing. MM is a medically challenging and stubborn disease with a disappointingly low rate of survival rate. When comparing the three most occurring blood cancers (i.e., lymphoma, leukemia, and myeloma), myeloma has the lowest 5-year survival rate (around 40%). A low survival rate indicates a high mortality rate with difficulty in treatment. Therefore, novel CAR-T cell-based therapies or combination therapies along with CAT-T cells may bring new hope for multiple myeloma patients. CAR-T cell therapy has a high potential to improve the remission success rate in patients with MM. To date, many preclinical and clinical trial studies have been conducted to investigate the ability and capacity of CAR T cells in targeting the antigens on myeloma cells. Despite the problems and obstacles, CAR-T cell experiments in MM patients revealed a robust therapeutic potential. However, several factors might be considered during CAR-T cell therapy for better response and reduced side effects. Also, incorporating the CAT-T cell method into a combinational treatment schedule may be a promising approach. In this paper, with a greater emphasis on CAR-T cell application in the treatment of MM, we will discuss and introduce CAR-T cell's history and functions, their limitations, and the solutions to defeat the limitations and different types of modifications on CAR-T cells.

Checkpoint Inhibitors and Engineered Cells: New Weapons for Natural Killer Cell Arsenal Against Hematological Malignancies

Natural killer (NK) cells represent one of the first lines of defense against malignant cells. NK cell activation and recognition are regulated by a balance between activating and inhibitory receptors, whose specific ligands can be upregulated on tumor cells surface and tumor microenvironment (TME). Hematological malignancies set up an extensive network of suppressive factors with the purpose to induce NK cell dysfunction and impaired immune-surveillance ability. Over the years, several strategies have been developed to enhance NK cells-mediated anti-tumor killing, while other approaches have arisen to restore the NK cell recognition impaired by tumor cells and other cellular components of the TME. In this review, we summarize and discuss the strategies applied in hematological malignancies to block the immune check-points and trigger NK cells anti-tumor effects through engineered chimeric antigen receptors.

Overview of anti-BCMA CAR-T immunotherapy for multiple myeloma and relapsed/refractory multiple myeloma

Multiple myeloma (MM) is a haematological malignancy caused by malignant proliferation of plasma cells in bone marrow. In recent years, MM patients are commonly treated with chemotherapy, autologous stem cell transplantation, protease inhibitors, immunomodulatory drugs and monoclonal antibodies, however most patients eventually relapse. Therefore, more effective therapies are highly needed. Anti-BCMA CAR-T therapy, a novel and efficacious method for treating MM and relapsed/refractory multiple myeloma (RRMM), has been designed and applied in clinics. The CAR-T can specifically recognize the targeted molecule B cell maturation antigen (BCMA) and kill MM cells expressing BCMA and several clinical trials have revealed high response rates in the therapy. Herein, we summarize the developments, the current design and clinical trials, the side effects of anti-BCMA CAR-T therapy and comparison of it with other CAR-T therapies.

Role of the Bone Marrow Milieu in Multiple Myeloma Progression and Therapeutic Resistance

Multiple myeloma (MM) is a cancer of the plasma cells within the bone marrow (BM). Studies have shown that the cellular and noncellular components of the BM milieu, such as cytokines and exosomes, play an integral role in MM pathogenesis and progression by mediating drug resistance and inducing MM proliferation. Moreover, the BM microenvironment of patients with MM facilitates cancer tolerance and immune evasion through the expansion of regulatory immune cells, inhibition of antitumor effector cells, and disruption of the antigen presentation machinery. These are of special relevance, especially in the current era of cancer immunotherapy. An improved understanding of the supportive role of the MM BM microenvironment will allow for the development of future therapies targeting MM in the context of the BM milieu to elicit deeper and more durable responses. In the present review, we have discussed our current understanding of the role of the BM microenvironment in MM progression and resistance to therapy and discuss novel potential approaches to alter its pro-MM function.

Emerging CAR landscape for cancer immunotherapy

In the last decade, there has been great advancement in manipulating the immune system or the cells of the immune system to bring about effective therapies. While harnessing the immune system against cancer is not a new concept, successful reprograming with T cells with chimeric antigen receptor (CAR) forming CAR-T cell therapy has revolutionized the treatment landscape for patients with refractory, high-grade B cell malignancies. The journey from proof-of-concept to FDA-approved commercial CAR-T products has taken almost 3 decades and untold amount of efforts, resources and manpower. With the success of CD19 CAR adoptive cellular immunotherapy leading the charge, CARs targeting various malignancies are in various stages of active development, racing towards regulatory approval, and raising hopes of further breakthroughs in cancer treatment options. In this review we will highlight recent clinical developments of the B cell maturation antigen (BCMA) CAR-T therapy for multiple myeloma (MM) to showcase how innovative CAR designs, coupled with careful selection of tumor-associated antigens, used in combination with other therapeutic agents, could help overcome some of the current limitations experienced in CAR-T immunotherapy. More patients could benefit from novel upfront cell therapy trials, that when combined with the current established induction regimens could have the potential to recondition and alter tumor environments, help restore somnolent anti-tumor immunity, and induce more effective and durable remissions.

Resistance Mechanisms Towards CD38-Directed Antibody Therapy in Multiple Myeloma

Antibodies targeting CD38 are rapidly changing the treatment landscape of multiple myeloma (MM). CD38-directed antibodies have several mechanisms of action. Fc-dependent immune effector mechanisms include complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) and apoptosis. In addition, direct effects and immunomodulatory effects contribute to the efficacy of CD38-directed antibodies. Daratumumab, the first-in-class anti-CD38 monoclonal antibody, is now part of standard treatment regimens of both newly diagnosed as well as relapsed/refractory MM patients. The FDA has recently approved isatuximab in combination with pomalidomide and dexamethasone for relapsed/refractory MM patients after at least two prior therapies. Further, the other CD38-targeting antibodies (i.e., MOR202 and TAK-079) are increasingly used in clinical trials. The shift to front-line treatment of daratumumab will lead to an increase in patients refractory to CD38 antibody therapy already after first-line treatment. Therefore, it is important to gain insight into the mechanisms of resistance to CD38-targeting antibodies in MM, and to develop strategies to overcome this resistance. In the current review, we will briefly describe the most important clinical data and mechanisms of action and will focus in depth on the current knowledge on mechanisms of resistance to CD38-targeting antibodies and potential strategies to overcome this.

Antibody therapies for multiple myeloma

Introduction: Multiple myeloma (MM) is characterized by the uncontrollable proliferation of plasma cells and the excessive production of a specific type of immunoglobulin. Immune system is deregulated in MM and, thus, immunotherapy is a promising therapeutic strategy.Areas covered: The first approach is to use monoclonal antibodies that recognize specific antigens on the surface of myeloma cells, such as CD38 and B-cell maturation antigen. Upon binding to their target, monoclonal antibodies activate the immune cells to destroy the malignant cell. Anti-CD38 molecules as part of highly effective combination regimens have been approved in both newly diagnosed and relapsed/refractory patients and have significantly changed the myeloma treatment landscape in the recent years. Another strategy is to use antibodies that bind both to a molecule on the surface of the myeloma cell and another molecule on the surface of a T-cell (bispecific antibodies). Consecutively, the T-cell comes close to and recognizes the myeloma cell. These have shown promising results in heavily pre-treated patients.Expert opinion: Antibody therapy has significantly enhanced the armamentarium against MM. Further research should focus on tailoring the combination regimens based on disease and patient characteristics in order to optimize the efficacy and safety.

In vitro Generation of Cytotoxic T Cells With Potential for Adoptive Tumor Immunotherapy of Multiple Myeloma

Multiple myeloma is a life-threatening hematological malignancy, which is rarely curable by conventional therapies. Immunotherapy, using tumor antigen-specific, cytotoxic T-lymphocytes, may represent an alternative or additional treatment for multiple myeloma. In this study, we used hybrid cell lines, generated by fusion of an EBV B-lymphoblastoid cell line (B-LCL) and myeloma cells, to stimulate in vitro peripheral blood lymphocytes (PBLs) from patients with multiple myeloma. We investigated induction of antigen-specific, cytotoxic T-lymphocytes to the well-defined tumor associated antigens (TAAs) hTERT, MUC1, MAGE-C1 and CS1, which have been shown to be expressed in a high proportion of cases of multiple myeloma. HLA-A2-peptide pentamer staining, interferon-γ and perforin ELISpot assays, as well as cytotoxicity assays were used. Following several rounds of in vitro stimulation, the hybrid cell lines induced antigen-specific, cytotoxic T-lymphocytes to four candidate TAAs in PBLs from HLA-A2⁺ multiple myeloma patients, using known HLA-A2 restricted peptide epitopes of the TAAs. In contrast, the HLA-A2⁺ myeloma cell line U266 failed to induce antigen-specific, cytotoxic T-lymphocytes in vitro. Our data indicate that B-LCL/myeloma hybrid cell lines induce antigen-specific, cytotoxic T-lymphocytes in PBLs isolated from multiple myeloma patients in vitro and may represent a novel strategy for use in adoptive immunotherapy of multiple myeloma.

Immunogenic Cell Death and Immunotherapy of Multiple Myeloma

Over the past decades, immunotherapy has demonstrated a prominent clinical efficacy in a wide variety of human tumors. For many years, apoptosis has been considered a non-immunogenic or tolerogenic process whereas necrosis or necroptosis has long been acknowledged to play a key role in inflammation and immune-related processes. However, the new concept of “immunogenic cell death” (ICD) has challenged this traditional view and has granted apoptosis with immunogenic abilities. This paradigm shift offers clear implications in designing novel anti-cancer therapeutic approaches. To date, several screening studies have been carried out to discover bona fide ICD inducers and reveal the inherent capacity of a wide variety of drugs to induce cell death-associated exposure of danger signals and to bring about in vivo anti-cancer immune responses. Recent shreds of evidence place ER stress at the core of all the scenarios where ICD occur. Furthermore, ER stress and the unfolded protein response (UPR) have emerged as important targets in different human cancers. Notably, in multiple myeloma (MM), a lethal plasma cell disorder, the elevated production of immunoglobulins leaves these cells heavily reliant on the survival arm of the UPR. For that reason, drugs that disrupt ER homeostasis and engage ER stress-associated cell death, such as proteasome inhibitors, which are currently used for the treatment of MM, as well as novel ER stressors are intended to be promising therapeutic agents in MM. This not only holds true for their capacity to induce cell death, but also to their potential ability to activate the immunogenic arm of the ER stress response, with the ensuing exposure of danger signals. We provide here an overview of the up-to-date knowledge regarding the cell death mechanisms involved in situations of ER stress with a special focus on the connections with the drug-induced ER stress pathways that evoke ICD. We will also discuss how this could assist in optimizing and developing better immunotherapeutic approaches, especially in MM treatment.

Treatment of Lymphoid and Myeloid Malignancies by Immunomodulatory Drugs

Thalidomide and its derivatives (lenalidomide, pomalidomide, avadomide, iberdomide hydrochoride, CC-885 and CC-90009) form the family of immunomodulatory drugs (IMiDs). Lenalidomide (CC5013, Revlimid®) was approved by the US FDA and the EMA for the treatment of multiple myeloma (MM) patients, low or intermediate-1 risk transfusion-dependent myelodysplastic syndrome (MDS) with chromosome 5q deletion [del(5q)] and relapsed and/or refractory mantle cell lymphoma following bortezomib. Lenalidomide has also been studied in clinical trials and has shown promising activity in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). Lenalidomide has anti-inflammatory effects and inhibits angiogenesis. Pomalidomide (CC4047, Imnovid® [EU], Pomalyst® [USA]) was approved for advanced MM insensitive to bortezomib and lenalidomide. Other IMiDs are in phases 1 and 2 of clinical trials. Cereblon (CRBN) seems to have an important role in IMiDs action in both lymphoid and myeloid hematological malignancies. Cereblon acts as the substrate receptor of a cullin-4 really interesting new gene (RING) E3 ubiquitin ligase CRL4CRBN. This E3 ubiquitin ligase in the absence of lenalidomide ubiquitinates CRBN itself and the other components of CRL4CRBN complex. Presence of lenalidomide changes specificity of CRL4CRBN which ubiquitinates two transcription factors, IKZF1 (Ikaros) and IKZF3 (Aiolos), and casein kinase 1α (CK1α) and marks them for degradation in proteasomes. Both these transcription factors (IKZF1 and IKZF3) stimulate proliferation of MM cells and inhibit T cells. Low CRBN level was connected with insensitivity of MM cells to lenalidomide. Lenalidomide decreases expression of protein argonaute-2, which binds to cereblon. Argonaute-2 seems to be an important drug target against IMiDs resistance in MM cells. Lenalidomide decreases also basigin and monocarboxylate transporter 1 in MM cells. MM cells with low expression of Ikaros, Aiolos and basigin are more sensitive to lenalidomide treatment. The CK1α gene (CSNK1A1) is located on 5q32 in commonly deleted region (CDR) in del(5q) MDS. Inhibition of CK1α sensitizes del(5q) MDS cells to lenalidomide. CK1α mediates also survival of malignant plasma cells in MM. Though, inhibition of CK1α is a potential novel therapy not only in del(5q) MDS but also in MM. High level of full length CRBN mRNA in mononuclear cells of bone marrow and of peripheral blood seems to be necessary for successful therapy of del(5q) MDS with lenalidomide. While transfusion independence (TI) after lenalidomide treatment is more than 60% in MDS patients with del(5q), only 25% TI and substantially shorter duration of response with occurrence of neutropenia and thrombocytopenia were achieved in lower risk MDS patients with normal karyotype treated with lenalidomide. Shortage of the biomarkers for lenalidomide response in these MDS patients is the main problem up to now.

Monoclonal Antibodies for the Treatment of Multiple Myeloma: An Update

The past two decades have seen a revolution in multiple myeloma (MM) therapy with the introduction of several small molecules, mostly orally effective, whose mechanisms are based on proteasome inhibition, histone deacetylase (HDAC) blockade, and immunomodulation. Immunotherapeutic approaches to MM treatment using monoclonal antibodies (mAbs), while long in development, began to reap success with the identification of CD38 and SLAMF7 as suitable targets for development, culminating in the 2015 Food and Drug Administration (FDA) approval of daratumumab and elotuzumab, respectively. This review highlights additional mAbs now in the developmental pipeline. Isatuximab, another anti-CD38 mAb, currently is under study in four phase III trials and may offer certain advantages over daratumumab. Several antibody-drug conjugates (ADCs) in the early stages of development are described, including JNJ-63723283, which has attained FDA breakthrough status for MM. Other mAbs described in this review include denosumab, recently approved for myeloma-associated bone loss, and checkpoint inhibitors, although the future status of the latter combined with immunomodulators has been clouded by unacceptably high death rates that caused the FDA to issue clinical holds on several of these trials. Also highlighted are the therapies based on the B Cell Maturation Antigen (BCMA), another very promising target for anti-myeloma development.

The application of CAR-T cell therapy in hematological malignancies: advantages and challenges

Chimeric antigen receptor T cell (CAR-T cell) therapy is a novel adoptive immunotherapy where T lymphocytes are engineered with synthetic receptors known as chimeric antigen receptors (CAR). The CAR-T cell is an effector T cell that recognizes and eliminates specific cancer cells, independent of major histocompatibility complex molecules. The whole procedure of CAR-T cell production is not well understood. The CAR-T cell has been used predominantly in the treatment of hematological malignancies, including acute lymphoblastic leukemia, chronic lymphocytic leukemia, lymphoma, and multiple myeloma. Solid tumors including melanoma, breast cancer and sarcoma offer great promise in CAR-T cell research and development. CD19 CAR-T cell is most commonly used, and other targets, including CD20, CD30, CD38 and CD138 are being studied. Although this novel therapy is promising, there are several disadvantages. In this review we discuss the applications of CAR-T cells in different hematological malignancies, and pave a way for future improvement on the effectiveness and persistence of these adoptive cell therapies.

The ceramide pathway is involved in the survival, apoptosis and exosome functions of human multiple myeloma cells in vitro

Multiple myeloma (MM) is characterized by the clonal proliferation of malignant plasma cells and refractoriness to traditional therapies. It has been shown that exosomes are involved in modulating the progression and the metastasis of cancers through microRNAs (miRs). Ceramide is a type of sphingolipid; the ceramide pathway of exosomal secretion has been shown to affect the apoptosis of cancer cells. But the role of this pathway in MM cell function, exosome function and miR regulation remains unknown. In this study, we showed that C6 ceramide (an exogenous ceramide supplement, 1.25-40 μmol/L) dose-dependently inhibited the proliferation and promoted the apoptosis in human MM OPM2 cell line, which were associated with elevated caspase 3/9 and PARP cleavage. We also found that C6 ceramide (5-20 μmol/L) dose-dependently stimulated exosome secretion and increased exosomal levels of tumor-suppressive miRs (miR 202, miR 16, miR 29b and miR 15a). Of note, exosomes from C6 ceramide-treated OPM2 cells could influence the proliferation and apoptosis of the recipient OPM2 cells, which correlated with increased tumor-suppressive exosomal miRs. In contrast, GW4869 (a ceramide inhibitor, 5-20 μmol/L) exerted the opposite effects on the regulation of MM function, exosome secretion and miR levels in MM exosomes. However, exosomes from GW4869-treated OPM2 cells had no effect on these miRs and the survival of targeted OPM2 cells. Taken together, our findings reveal that the ceramide pathway modulates MM survival, probably directly via the caspase pathway and indirectly via exosomal miR mechanisms.

Advances in immunotherapy in multiple myeloma

PURPOSE OF REVIEW

Here, we explore the significant progress made in the treatment of multiple myeloma, focusing on immunotherapy and the promise it has offered to patients suffering from advanced disease.

RECENT FINDINGS

Multiple myeloma, a B-cell malignancy, is characterized by unregulated plasma cell growth in the bone marrow as well as strong immunosuppression in the tumor microenvironment. mAbs targeting tumor antigens overcome this, increasing T-cell activation, multiple myeloma cell death, and depth of response. Similarly, adoptive T-cell therapy aims to engineer or isolate tumor-specific T cells for a targeted approach. Finally, peptide and dendritic cell/tumor fusion vaccines reeducate the immune system, expanding the immune response and generating long-term memory to prevent relapse of disease. Many of these approaches have been combined with existing therapies to enhance antitumor immunity.

SUMMARY

Immunotherapeutic approaches have remarkably changed the treatment paradigm for multiple myeloma, and encouraging patient responses have warranted further investigation into mAbs, adoptive T-cell therapy, vaccines, and combination therapy.

Clinical pharmacokinetics of oral drugs in the treatment of multiple myeloma

Treatment of myeloma is a long-term treatment mainly based on all-oral combinations of drugs. Because oral drugs have a more complex pharmacokinetics compared with IV treatments, an appropriate knowledge of the factors that may alter their systemic exposure is of particular clinical relevance. Both drug-drug interactions, food-effect, and dose-adaptation in renal and hepatic impairment may influence the systemic drug levels with a potential impact on drug efficacy or safety. Moreover, a better control of drug exposure may improve the side effect profiles of these treatments with a favourable impact on patient compliance. Furthermore, as long-term treatments, these drugs may also alter the systemic exposure of coadministered medications in these rather old patients. The aim of this review was to identify the factors modifying the systemic exposure of oral drugs used in myeloma by focusing on the pharmacokinetic drug-drug interactions and the effects of renal and hepatic impairment and of food impact.

Abnormal repression of SHP-1, SHP-2 and SOCS-1 transcription sustains the activation of the JAK/STAT3 pathway and the progression of the disease in multiple myeloma

Sustained activation of JAK/STAT3 signaling pathway is classically described in Multiple Myeloma (MM). One explanation could be the silencing of the JAK/STAT suppressor genes, through the hypermethylation of SHP-1 and SOCS-1, previously demonstrated in MM cell lines or in whole bone marrow aspirates. The link between such suppressor gene silencing and the degree of bone marrow invasion or the treatment response has not been evaluated in depth. Using real-time RT-PCR, we studied the expression profile of three JAK/STAT suppressor genes: SHP-1, SHP-2 and SOCS-1 in plasma cells freshly isolated from the bone marrows of MM patients and healthy controls. Our data demonstrated an abnormal repression of such genes in malignant plasma cells and revealed a significant correlation between such defects and the sustained activation of the JAK/STAT3 pathway during MM. The repressed expression of SHP-1 and SHP-2 correlated significantly with a high initial degree of bone marrow infiltration but was, unexpectedly, associated with a better response to the induction therapy. Collectively, our data provide new evidences that substantiate the contribution of JAK/STAT suppressor genes in the pathogenesis of MM. They also highlight the possibility that the decreased gene expression of SHP-1 and SHP-2 could be of interest as a new predictive factor of a favorable treatment response, and suggest new potential mechanisms of action of the therapeutic molecules. Whether such defect helps the progression of the disease from monoclonal gammopathy of unknown significance to MM remains, however, to be determined.