APRIL and BCMA promote human multiple myeloma growth and immunosuppression in the bone marrow microenvironment

B-Cell Maturation Antigen-Directed Immunotherapies for the Treatment of Relapsed/Refractory Multiple Myeloma: A Review of the Literature and Implications for Clinical Practice

OBJECTIVE

To review the pharmacology, efficacy, safety, dosing and administration, and relevance to patient care and clinical practice of B-cell maturation antigen (BCMA) directed immunotherapies, including chimeric antigen receptor T-cell (CAR-T) therapy and bispecific antibodies (BsAb), for the management of relapsed/refractory multiple myeloma (RRMM).

DATA SOURCES

A literature review of PubMed (1966 to July 2024) was conducted using the keywords idecabtagene vicleucel, ciltacabtagene autoleucel, teclistamab, elranatamab, and multiple myeloma. Data was also obtained from unpublished meeting abstracts and prescribing information.

STUDY SELECTION AND DATA EXTRACTION

All relevant published articles, unpublished abstracts, and prescribing information on anti-BCMA immunotherapies for the treatment of RRMM were reviewed.

DATA SYNTHESIS

Idecabtagene vicleucel and ciltacabtagene autoleucel are BCMA-directed CAR-T cell therapies that have been compared to standard of care (SOC) regimens for MM in early relapse in the phase III trials KarMMa-3 and CARTITUDE-4, respectively. Both studies demonstrated a significantly improved in response rates, depth of response, and progression-free survival compared to SOC. BsAbs teclistamab and elranatamab have been evaluated in the phase II trials MajesTEC-1 and MagnetisMM-3, respectively. Overall response rates of 63 and 61% were observed with teclistamab and elranatamab, respectively, in a population of patients with heavily pretreated RRMM.Relevance to Patient Care and Clinical Practice in Comparison with Existing Drugs:BCMA-directed immunotherapies have demonstrated efficacy in the treatment of RRMM. Safety issues with BCMA-directed immunotherapies include cytokine release syndrome, neurotoxicity, infections, and cytopenias. Operational challenges and issues with access to care exist with these therapies as they may be limited to institutions with the infrastructure to safely administer and monitor patients for toxicities.

CONCLUSION

BCMA-directed immunotherapies represent an important advancement in the management of RRMM and have significantly added to the available treatment options for this disease.

Mechanisms for resistance to BCMA-targeted immunotherapies in multiple myeloma

Multiple myeloma (MM) remains incurable and patients eventually face the relapse/refractory dilemma. B cell maturation antigen (BCMA)-targeted immunotherapeutic approaches have shown great effectiveness in patients with relapsed/refractory MM, mainly including chimeric antigen receptor T cells (CAR-T), bispecific T cell engagers (TCEs), and antibody-drug conjugates (ADCs). However, their impact on long-term survival remains to be determined. Nonetheless, resistance to these novel therapies is still inevitable, raising a challenge that we have never met in both laboratory research and clinical practice. In this scenario, the investigation aiming to enhance and prolong the anti-MM activity of BCMA-targeted therapies has been expanding rapidly. Despite considerable uncertainty in our understanding of the mechanisms for their resistance, they have mainly been attributed to antigen-dependency, T cell-driven factors, and (immune) tumor microenvironment. In this review, we summarize the current understanding of the mechanisms for resistance to BCMA-targeted immunotherapies and discuss potential strategies for overcoming it.

Neurotoxicity and Rare Adverse Events in BCMA-Directed CAR T Cell Therapy: A Comprehensive Analysis of Real-World FAERS Data

Chimeric antigen receptor T (CAR T) cell therapies have emerged as a valuable treatment modality for patients with plasma cell disorders. As the population of patients receiving CAR T therapies grows, the identification and management of associated rare toxicities become increasingly crucial. This study aims to identify safety signals associated with commercial anti-B-cell maturation antigen (BCMA) CAR T therapies using the Food and Drug Administration Adverse Event Reporting System (FAERS). We performed a cross-sectional analysis of the adverse events (AE) reports associated with ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), submitted to FAERS between January 2021 and December 2023. AE frequencies were summarized using descriptive statistics, and safety signals were explored by measuring the reporting odds ratio (ROR) compared to control groups. Among 4,472,782 unique FAERS reports, 1,496 involved BCMA-directed CAR-T therapies. AEs reported more frequently included immune-associated conditions and neurological disorders. Neurotoxicity associated with cilta-cel predominantly manifested as cranial nerve palsies, Parkinson's disease and parkinsonism, and acute and chronic polyneuropathies, while ide-cel neurotoxicity presented as confusion, disorientation, seizures, balance disturbances, and tremors. In cilta-cel reports, other safety signals included Guillain-Barre syndrome (ROR: 17.1, 95% CI 6.1 to 47.5), intracranial hemorrhage and cerebrovascular accidents (ROR: 2.9, 95% CI 1.8 to 4.8), Haemophilus infections (ROR: 34.2, 95% CI 11.8 to 98.9) and cytomegalovirus infections (ROR: 3.9, 95% CI 1.6 to 9.5). For ide-cel, new signals included parkinsonism (ROR: 13.7, 95% CI 5.5 to 34.5), acute and chronic sarcoidosis (ROR: 197.1, 95% CI 32.9 to 1180.1), ventricular arrhythmias, and cardiac arrest (ROR: 3.9, 95% CI 2.1 to 7.3). This analysis provides a comprehensive insight into the safety profiles of the commercial BCMA-directed CAR T therapies, underscoring the importance of vigilant post-marketing surveillance to mitigate potential risks.

Targets Selection for Precision Therapy of Relapsed/Refractory Multiple Myeloma: the Latest Advancements

OPINION STATEMENT

According to the guidelines, the primary treatment for multiple myeloma is still based on drugs such as carfilzomib, lenalidomide, or daratumumab. However, patients with relapsed/refractory multiple myeloma (RRMM) may be insensitive or develop resistance to the above therapeutic medications. Thus, formulating standardized and rational treatment regimens for such patients remains an area for consideration. Multidrug combinations are available for the therapy of patients with relapsed/refractory multiple myeloma to improve their clinical outcome and prevent the occurrence of multidrug resistance. For instance, combination therapy with immunomodulators, proteasome inhibitors, and CD38 monoclonal antibodies. With the development of genomics and molecular diagnostic technologies, RRMM has entered the era of precision therapy. Targeted immunotherapeutic drugs such as monoclonal antibodies, bispecific antibodies, antibody-drug conjugates (ADCs), and chimeric antigen receptor-T (CAR-T) cells have shown promising clinical response rates and favorable safety profiles in several clinical and experimental studies. These cutting-edge medicinal treatments may provide new hope for a cure for RRMM. However, the choice of treatment regimen still needs to adhere to the principle of individualization. Generally, we recommend treatment with drugs of a new generation or novel mechanism of action for patients with RRMM who are first relapsed, such as next-generation proteasome inhibitors, next-generation immunomodulators, and CD38-based monoclonal antibody regimens. For multiple relapsed RRMM, we recommend choosing a combination regimen or participating in relevant clinical trials. Additionally, monoclonal antibodies have become the standard of care for patients with RRMM. With the introduction of CAR-T therapy, ADCs, and bispecific antibodies, RRMM patients are expected to achieve deep remissions and long-term survival again.

Single-cell analysis of the multiple myeloma microenvironment after γ-secretase inhibition and CAR T-cell therapy

ABSTRACT

Chimeric antigen receptor (CAR) T cells and bispecific antibodies targeting B-cell maturation antigen (BCMA) have significantly advanced the treatment of relapsed and refractory multiple myeloma. Resistance to BCMA-targeting therapies, nonetheless, remains a significant challenge. BCMA shedding by γ-secretase is a known resistance mechanism, and preclinical studies suggest that inhibition may improve anti-BCMA therapy. Leveraging a phase 1 clinical trial of the γ-secretase inhibitor (GSI), crenigacestat, with anti-BCMA CAR T cells (FCARH143), we used single-nuclei RNA sequencing and assay for transposase-accessible chromatin sequencing to characterize the effects of GSI on the tumor microenvironment. The most significant impacts of GSI involved effects on monocytes, which are known to promote tumor growth. In addition to observing a reduction in the frequency of nonclassical monocytes, we also detected significant changes in gene expression, chromatin accessibility, and inferred cell-cell interactions after exposure to GSI. Although many genes with altered expression are associated with γ-secretase-dependent signaling, such as Notch, other pathways were affected, indicating GSI has far-reaching effects. Finally, we detected monoallelic deletion of the BCMA locus in some patients with prior exposure to anti-BCMA therapy, which significantly correlated with reduced progression-free survival (PFS; median PFS, 57 vs 861 days). GSIs are being explored in combination with the full spectrum of BCMA-targeting agents, and our results reveal widespread effects of GSI on both tumor and immune cell populations, providing insight into mechanisms for enhancing BCMA-directed therapies.

Idecabtagene vicleucel (ide-cel) for the treatment of triple-class exposed relapsed and refractory multiple myeloma

INTRODUCTION

Modern anti-myeloma therapies have broken new ground in the treatment of the disease, and the incorporation of ide-cel in the treatment landscape represents one of the major scientific and clinical advances.

AREAS COVERED

Ide-cel was the first cell-based gene therapy approved for the treatment of triple-class exposed relapsed/refractory myeloma patients, showing impressive results, and demonstrating superiority over standard regimens in terms of efficacy, potential treatment-free intervals, and improved quality of life in heavily pretreated patients and in high-risk disease. This review summarizes the state-of-the-art of the most recent updates deriving from the use of ide-cel within ongoing, or upcoming, clinical trials, and from real-life experiences.

EXPERT OPINION

As the use of chimeric antigen receptor (CAR)-T therapy is likely to progressively increase over time and current indications expand to earlier treatment lines, efforts should be directed toward ameliorating overall management to facilitate proactive planning for treatment sequencing and provide adequate time for logistical planning. Importantly, the potential limited availability of CAR-T therapy highlights the importance of careful patient selection and coordination among centers. Meanwhile, attempts are underway to improve tolerance and reduce toxicity while enhancing anti-myeloma activity.

Bispecific antibody and chimeric antigen receptor (CAR) modified T-cell in the treatment of multiple myeloma: Where do we stand today?

Although the prognosis of patients with multiple myeloma (MM) has been significantly improved by the introduction of proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies, MM is still considered an incurable disease in the vast majority of the patients. In recent years, T-cell based immunotherapy represents a novel treatment strategy for relapsed/refractory (RR) MM. So far, chimeric antigen receptor (CAR) modified T-cells and bispecific T-cell engaging antibodies (bsAb) have shown promising anti-MM efficacy and manageable safety profile within clinical trials, and B-cell maturation antigen (BCMA) is the most commonly used immune target for T-cell based immunotherapies in MM. To date, several CAR T-cell and bsAb products have already been approved for the treatment of RRMM, leading to a paradigm shift in the MM therapy and providing a potential curative option. In this review, we provide a summary of mechanisms of action, immune targets, selected clinical data, resistance mechanisms and therapy sequencing of CAR T-cell and bsAb in MM.

New horizons in our understanding of precursor multiple myeloma and early interception

Multiple myeloma is an incurable plasma cell malignancy that evolves over decades through the selection and malignant transformation of monoclonal plasma cells. The evolution from precursor states to symptomatic disease is characterized by an increasing complexity of genomic alterations within the plasma cells and a remodelling of the microenvironment towards an immunosuppressive state. Notably, in patients with advanced disease, similar mechanisms of tumour escape and immune dysfunction mediate resistance to modern T cell-based therapies, such as T cell-engaging bispecific antibodies and chimeric antigen receptor (CAR)-T cells. Thus, an increasing number of clinical trials are assessing the efficiency and safety of these therapies in individuals with newly diagnosed multiple myeloma and high-risk smoldering multiple myeloma. In this Review, we summarize the current knowledge about tumour intrinsic and extrinsic processes underlying progression from precursor states to symptomatic myeloma and discuss the rationale for early interception including the use of T cell-redirecting therapies.

Comparison of CAR T-cell and bispecific antibody as third-line or later-line treatments for multiple myeloma: a meta-analysis

BACKGROUND

CAR-T-cell therapy and bispecific antibody have revolutionized the treatment landscape for multiple myeloma. However, there is currently a lack of studies comparing the efficacy and safety of these two approaches. This meta-analysis assesses the efficacy and safety of B-cell maturation antigen (BCMA)-directed CAR-T-cell therapies and BCMA×CD3 bispecific antibodies as third-line or later interventions for relapsed/refractory multiple myeloma (RRMM).

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane databases up to May 31, 2024, identifying 11 eligible studies encompassing 1269 participants. Random-effects models evaluated the primary (complete response (CR) rate) and secondary (overall response rate (ORR)) outcomes, while meta-regression analyses adjusted for relevant covariates.

RESULTS

CAR-T-cell therapy achieved significantly higher pooled CR rate (0.54 (95% CI 0.42-0.69) vs bispecific antibodies 0.35 (0.30-0.41), p<0.01) and pooled ORR (0.83 (0.76-0.90) vs 0.65 (0.59-0.71), p<0.01). However, CAR-T therapy had a higher incidence of adverse events, particularly cytokine release syndrome (CRS 0.83 (0.70-0.97) vs bispecific antibodies 0.59 (0.43-0.74), p<0.05). Severe CRS (grade ≥3) occurred at a rate of 0.07 (0.03-0.14) in the CAR-T cell group, contrasting with a negligible rate of 0.01 (0.00-0.02) in the bispecific antibody group (p<0.01). Hematologic adverse events, including neutropenia (grade ≥3; 0.88 (0.81-0.95) vs 0.48 (0.30-0.67), p<0.01) and anemia (grade≥3; 0.55 (0.47-0.62) vs 0.34 (0.28 to 0.40), p<0.01), were also more frequent in the CAR-T-cell group. Furthermore, differences in efficacy were observed among various CAR-T products, with ciltacabtagene autoleucel showing greater efficacy in CR rate (0.77 (0.71-0.84) vs 0.37 (0.32-0.41), p<0.01) and ORR (0.91 (0.83-0.99) vs 0.73 (0.68-0.77), p<0.01) compared with idecabtagene vicleucel.

CONCLUSION

CAR-T-cell therapy demonstrated superior CR rates compared with bispecific antibodies, although with an increase in severe adverse events.

TGF-β: an active participant in the immune and metabolic microenvironment of multiple myeloma : TGF-β in the microenvironment of multiple myeloma

Although substantial quantities of potent therapies for multiple myeloma (MM) have been established, MM remains an incurable disease. In recent years, our understanding of the initiation, development, and metastasis of cancers has made a qualitative leap. Cancers attain the abilities to maintain proliferation signals, escape growth inhibitors, resist cell death, induce angiogenesis, and more importantly, escape anti-tumor immunity and reprogram metabolism, which are the hallmarks of cancers. Besides, different cancers have different tumor microenvironments (TME), thus, we pay more attention to the TME in the pathogenesis of MM. Many researchers have identified that myeloma cells interact with the components of TME, which is beneficial for their survival, ultimately causing the formation of immunosuppressive and high-metabolism TME. In the process, transforming growth factor-β (TGF-β), as a pivotal cytokine in the TME, controls various cells' fates and influences numerous metabolic pathways, including inhibiting immune cells to infiltrate the tumors, suppressing the activation of anti-tumor immune cells, facilitating more immunosuppressive cells, enhancing glucose and glutamine metabolism, dysregulating bone metabolism and so on. Thus, we consider TGF-β as the tumor promoter. However, in healthy cells and the early stage of tumors, it functions as a tumor suppressor. Due to the effect of context dependence, TGF-β has dual roles in TME, which attracts us to further explore whether targeting it can overcome obstacles in the treatment of MM by regulating the progression of myeloma, molecular mechanisms of drug resistance, and various signaling pathways in the immune and metabolic microenvironment. In this review, we predominantly discuss that TGF-β promotes the development of MM by influencing immunity and metabolism.

Advances in adoptive cellular immunotherapy and therapeutic breakthroughs in multiple myeloma

The basic idea of modulating the immune system to better recognize and fight tumor cells has led to the successful introduction of adoptive cellular immunotherapy (ACT). ACT-based treatment regimens, in which the patient's own immune cells are isolated and subsequently expanded (ex vivo) and reinfused, have also contributed significantly to the development of a personalized treatment strategy. Complementing this, the unprecedented advances in ACTs as chimeric antigen receptor (CAR)-T cell therapies and their derivatives such as CAR-NK, CAR-macrophages, CAR-γδT and CAR-NKT have further maximized the therapeutic outcomes. Herein, we provide a comprehensive overview of the development of ACTs in multiple myeloma (MM) and outline how they have evolved from an experimental form to a mainstay of standard clinical settings. Besides, we provide insights into cytokine-induced killer cell (CIK) therapy, an alternative form of ACT that (as CIK or CAR-CIK) has enormous potential in the clinical spectrum of MM. We also summarize the results of the major preclinical and clinical studies of adoptive cell therapy in MM and address the current challenges (such as cytokine release syndrome (CRS) and neurotoxicity) that limit its complete success in the cancer landscape.

Mechanisms and salvage treatments in patients with multiple myeloma relapsed post-BCMA CAR-T cell therapy

Chimeric antigen receptor T-cell (CAR-T) therapy has ushered in a new era for the treatment of multiple myeloma (MM). Numerous clinical studies, especially those involving B-cell maturation antigen (BCMA)-directed CAR-T, have shown remarkable efficacy in patients with relapsed or refractory multiple myeloma (R/R MM). However, a considerable number of patients still experience disease recurrence or progression after BCMA CAR-T treatment, which is attributed to various factors, including antigen escape, CAR-T manufacturing factors, T cell exhaustion, inhibitory effects of tumor microenvironment and impact of prior treatments. The scarcity of effective treatment options following post-CAR-T disease recurrence, coupled with the lack of well-established salvage regimens, leaves patients who do relapse facing a bleak prognosis. In recent years, some academic institutions have achieved certain results in salvage treatments of patients with relapse after BCMA CAR-T treatment through secondary infusion of BCMA CAR-T, changing to non-BCMA-directed CAR-T, double-target CAR-T, bispecific antibodies or other novel therapies. This review summarizes the mechanisms of resistance or relapse after BCMA CAR-T administration and the available data on current salvage treatments, hoping to provide ideas for optimizing clinical salvage therapies.

Revolutionizing cancer treatment: an in-depth exploration of CAR-T cell therapies

Cancer is a leading cause of fatality worldwide. Due to the heterogeneity of cancer cells the effectiveness of various conventional cancer treatment techniques is constrained. Thus, researchers are diligently investigating therapeutic approaches like immunotherapy for effective tumor managements. Immunotherapy harnesses the inherent potential of patient's immune system to achieve desired outcomes. Within the realm of immunotherapy, CAR-T (Chimeric Antigen Receptor T) cells, emerges as a revolutionary innovation for cancer therapy. The process of CAR-T cell therapy entails extracting the patient's T cells, altering them with customized receptors designed to specifically recognize and eradicate the tumor cells, and then reinfusing the altered cells into the patient's body. Although there has been significant progress with CAR-T cell therapy in certain cases of specific B-cell leukemia and lymphoma, its effectiveness is hindered in hematological and solid tumors due to the challenges such as severe toxicities, restricted tumor infiltration, cytokine release syndrome and antigen escape. Overcoming these obstacles requires innovative approaches to design more effective CAR-T cells, which require a competent and diverse team to develop and implement. This comprehensive review addresses numerous therapeutic issues and provides a strategic solution while providing a deep understanding of the structural intricacies and production processes of CAR-T cells. In addition, this review explores the practical aspects of CAR-T cell therapy in clinical settings.

Targeting B-cell maturation antigen for treatment and monitoring of relapsed/refractory multiple myeloma patients: a comprehensive review

Despite major therapeutic advancements in recent years, multiple myeloma (MM) remains an incurable disease with nearly all patients experiencing relapsed and refractory disease over the course of treatment. Extending the duration and durability of clinical responses will necessitate the development of therapeutics with novel targets that are capable of robustly and specifically eliminating myeloma cells. B-cell maturation antigen (BCMA) is a membrane-bound protein expressed predominantly on malignant plasma cells and has recently been the target of several novel therapeutics to treat MM patients. This review will focus on recently approved and currently in development agents that target this protein, including bispecific antibodies, antibody-drug conjugates, and chimeric antigen receptor T-cell therapies. In addition, this protein also serves as a novel serum biomarker to predict outcomes and monitor disease status for MM patients; the studies demonstrating this use of BCMA will be discussed in detail.

Updates on CAR T cell therapy in multiple myeloma

Multiple myeloma (MM) is a hematological cancer characterized by the abnormal proliferation of plasma cells. Initial treatments often include immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (mAbs). Despite salient progress in diagnosis and treatment, most MM patients typically have a median life expectancy of only four to five years after starting treatment. In recent developments, the success of chimeric antigen receptor (CAR) T-cells in treating B-cell malignancies exemplifies a new paradigm shift in advanced immunotherapy techniques with promising therapeutic outcomes. Ide-cel and cilta-cel stand as the only two FDA-approved BCMA-targeted CAR T-cells for MM patients, a recognition achieved despite extensive preclinical and clinical research efforts in this domain. Challenges remain regarding certain aspects of CAR T-cell manufacturing and administration processes, including the lack of accessibility and durability due to T-cell characteristics, along with expensive and time-consuming processes limiting health plan coverage. Moreover, MM features, such as tumor antigen heterogeneity, antigen presentation alterations, complex tumor microenvironments, and challenges in CAR-T trafficking, contribute to CAR T-cell exhaustion and subsequent therapy relapse or refractory status. Additionally, the occurrence of adverse events such as cytokine release syndrome, neurotoxicity, and on-target, off-tumor toxicities present obstacles to CAR T-cell therapies. Consequently, ongoing CAR T-cell trials are diligently addressing these challenges and barriers. In this review, we provide an overview of the effectiveness of currently available CAR T-cell treatments for MM, explore the primary resistance mechanisms to these treatments, suggest strategies for improving long-lasting remissions, and investigate the potential for combination therapies involving CAR T-cells.

Elranatamab in Japanese patients with relapsed/refractory multiple myeloma: results from MagnetisMM-2 and MagnetisMM-3

BACKGROUND

Despite advances, most patients with multiple myeloma (MM) experience relapse and repeat multiple treatment lines, highlighting an unmet need for patients with relapsed or refractory MM (RRMM). Bispecific antibodies are a new option, but their efficacy and safety in Japanese patients are unknown.

METHODS

This was an analysis of Japanese patients receiving elranatamab monotherapy in MagnetisMM-2 (NCT04798586) and MagnetisMM-3 (NCT04649359). Both studies evaluated a priming dose regimen of elranatamab followed by weekly subcutaneous doses, in patients with disease progression while receiving or who were intolerant to ≥3 prior therapies (≥1 proteasome inhibitor, ≥1 immunomodulatory drug and ≥1 anti-CD38 monoclonal antibody). The primary endpoints were dose limiting toxicities (DLTs) in MagnetisMM-2 and confirmed objective response rate (ORR) in MagnetisMM-3. In both, key secondary endpoints included safety, tolerability, duration of response, time to response, progression-free survival and overall survival.

RESULTS

In MagnetisMM-2 (N = 4) and MagnetisMM-3 (n = 12), median ages were 68.5 and 66.5 years, respectively. No DLTs were observed in MagnetisMM-2. ORRs were 50.0% (95% CI, 6.8-93.2) and 58.3% (95% CI, 27.7-84.8) in MagnetisMM-2 and MagnetisMM-3, respectively. All patients experienced treatment-emergent adverse events in MagnetisMM-2 (grade 3/4: 75.0%) and MagnetisMM-3 (grade 3/4: 100%); cytokine release syndrome occurred in 100% (grade 3/4: 25.0%) and 58.3% (no grade 3/4) of patients, respectively. Neither study reported immune effector cell-associated neurotoxicity syndrome.

CONCLUSIONS

No new safety signals were observed, and ORRs were similar to that of the overall MagnetisMM-3 trial population, supporting further studies of elranatamab in Japanese patients with RRMM. ClinicalTrials.gov identifier: NCT04798586 (MagnetisMM-2), NCT04649359 (MagnetisMM-3).

Proteomic signatures improve risk prediction for common and rare diseases

For many diseases there are delays in diagnosis due to a lack of objective biomarkers for disease onset. Here, in 41,931 individuals from the United Kingdom Biobank Pharma Proteomics Project, we integrated measurements of ~3,000 plasma proteins with clinical information to derive sparse prediction models for the 10-year incidence of 218 common and rare diseases (81-6,038 cases). We then compared prediction models developed using proteomic data with models developed using either basic clinical information alone or clinical information combined with data from 37 clinical assays. The predictive performance of sparse models including as few as 5 to 20 proteins was superior to the performance of models developed using basic clinical information for 67 pathologically diverse diseases (median delta C-index = 0.07; range = 0.02-0.31). Sparse protein models further outperformed models developed using basic information combined with clinical assay data for 52 diseases, including multiple myeloma, non-Hodgkin lymphoma, motor neuron disease, pulmonary fibrosis and dilated cardiomyopathy. For multiple myeloma, single-cell RNA sequencing from bone marrow in newly diagnosed patients showed that four of the five predictor proteins were expressed specifically in plasma cells, consistent with the strong predictive power of these proteins. External replication of sparse protein models in the EPIC-Norfolk study showed good generalizability for prediction of the six diseases tested. These findings show that sparse plasma protein signatures, including both disease-specific proteins and protein predictors shared across several diseases, offer clinically useful prediction of common and rare diseases.

Halting multiple myeloma with MALT1 inhibition: suppressing BCMA-induced NF-κB and inducing immunogenic cell death

ABSTRACT

Because multiple myeloma (MM) poses a formidable therapeutic challenge despite recent progress, exploring novel targets is crucial. Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) emerges as a promising paracaspase with druggable potential, especially unexplored in MM. Our study provided compelling evidence demonstrating a statistically significant elevation of MALT1 expression in human primary MM cells. Moreover, elevated MALT1 expression was associated with a poorer prognosis in MM. Genetic deletion of MALT1 reduced cell growth, colony formation, and tumor growth in vivo. Pharmacological inhibition with 1 μM of a small-molecular MALT1 inhibitor, Mi-2, effectively inhibited cell growth, inducing mitochondria-dependent apoptotic cell death. Mechanistically, MALT1 inhibition disrupted diverse signal transduction pathways, notably impeding nuclear factor κB (NF-κB). Significantly, the inhibition of MALT1 demonstrated a substantial suppression of NF-κB activation by elevating inhibitor of NF-κB, disrupting the nuclear localization of p65 and c-REL. This effect was observed in both the basal state and when stimulated by B-cell maturation antigen, highlighting the pivotal role of MALT1 inhibition in influencing MM cell survival. It was noteworthy that Mi-2 induces properties associated with immunogenic cell death (ICD), as evidenced by increased calreticulin, adenosine triphosphate release, and high-mobility group protein B1 upregulation, consequently triggering ICD-associated immune activation and enhancing CD8+ T-cell cytotoxicity in vitro. In conclusion, our research highlights MALT1 as a promising druggable target for therapeutic interventions in MM, providing insights into its molecular mechanisms in MM progression.

Just scratching the surface: novel treatment approaches for multiple myeloma targeting cell membrane proteins

A better understanding of the roles of the adaptive and innate immune systems in the oncogenesis of cancers including multiple myeloma (MM) has led to the development of novel immune-based therapies. B cell maturation antigen (BCMA), G protein-coupled receptor family C group 5 member D (GPRC5D) and Fc receptor-like protein 5 (FcRL5, also known as FcRH5) are cell-surface transmembrane proteins expressed by plasma cells, and have been identified as prominent immunotherapeutic targets in MM, with promising activity demonstrated in patients with heavily pretreated relapsed and/or refractory disease. Indeed, since 2020, antibody-drug conjugates, bispecific T cell engagers and autologous chimeric antigen receptor T cells targeting BCMA or GPRC5D have been approved for the treatment of relapsed and/or refractory MM. However, responses to these therapies are not universal, and acquired resistance invariably occurs. In this Review, we discuss the various immunotherapeutic approaches targeting BCMA, GPRC5D and FcRL5 that are currently either available or in clinical development for patients with MM. We also review the mechanisms underlying resistance to such therapies, and discuss potential strategies to overcome these mechanisms and improve patient outcomes.

Mechanisms of resistance to bispecific T-cell engagers in multiple myeloma and their clinical implications

ABSTRACT

Bispecific T-cell engagers (TCEs) are revolutionizing patient care in multiple myeloma (MM). These monoclonal antibodies, that redirect T cells against cancer cells, are now approved for the treatment of triple-class exposed relapsed/refractory MM (RRMM). They are currently tested in earlier lines of the disease, including in first line. Yet, primary resistance occurs in about one-third of patients with RRMM, and most responders eventually develop acquired resistance. Understanding the mechanisms of resistance to bispecific TCE is thus essential to improve immunotherapies in MM. Here, we review recent studies investigating the clinical and molecular determinants of resistance to bispecific TCE. Resistance can arise from tumor-intrinsic or tumor-extrinsic mechanisms. Tumor-intrinsic resistance involves various alterations leading to the loss of the target antigen, such as chromosome deletions, point mutations, or epigenetic silencing. Loss of major histocompatibility complex (MHC) class I, preventing MHC class I: T-cell receptor (TCR) costimulatory signaling, was also reported. Tumor-extrinsic resistance involves abundant exhausted T-cell clones and several factors generating an immunosuppressive microenvironment. Importantly, some resistance mechanisms impair response to 1 TCE while preserving the efficacy of others. We next discuss the clinical implications of these findings. Monitoring the status of target antigens in tumor cells and their immune environment will be key to select the most appropriate TCE for each patient and to design combination and sequencing strategies for immunotherapy in MM.

Exploring the therapeutic mechanisms of Coptidis Rhizoma in gastric precancerous lesions: a network pharmacology approach

BACKGROUND

Gastric precancerous lesions are a critical stage in the development of gastric cancer or gastric adenocarcinoma, and their outcome plays an important role in the malignant progression of gastric cancer. Coptidis Rhizoma has a good effect on Gastric precancerous lesions. However, the specific mechanisms of its action remain incompletely elucidated.

METHODS

Network pharmacology and molecular docking techniques were used to explore the active ingredients and molecular mechanism of Coptidis Rhizoma in treating gastric precancerous lesions. The active compounds of Coptidis Rhizoma and their potential gastric precancerous lesions related targets were obtained from TCMSP, GeneCards, and OMIM databases. An interaction network based on protein-protein interactions (PPIs) was constructed to visualize the interactions between hub genes. Analysis of GO enrichment and KEGG pathway were conducted using the DAVID database. An investigation of interactions between active compounds and potential targets was carried out by molecular docking. Finally, animal experiments were conducted to verify the effect and mechanism of Coptidis Rhizoma in treating precancerous lesions of gastric cancer.

RESULTS

A total of 11 active compounds and 95 anti-gastric precancerous lesions targets of Coptidis Rhizoma were screened for analysis. GO enrichment analysis showed that the mechanism of Coptidis Rhizoma acting on gastric precancerous lesions involves gene expression regulation and apoptosis regulation. KEGG pathway enrichment analysis showed that Coptidis Rhizoma against gastric precancerous lesions involving the AKT /HIF-1α/VEGF signalling pathway. Molecular docking simulations indicated potential interactions between these compounds and core targets involved in anti-gastric precancerous lesions activity. In addition, it was confirmed in vivo that Berberine and Coptidis Rhizoma may reverse atrophy and potential intestinal metaplasia by inhibiting the expression of p-AKT, HIFA, and VEGF.

CONCLUSION

Bioactive compounds in Coptidis Rhizoma have the potential to prevent atrophy and intestinal metaplasia. These compounds function by regulating the proteins implicated in AKT /HIF-1α/VEGF signalling pathways that are crucial in gastric epithelial cell differentiation, proliferation and maturation.

Beyond BCMA: the next wave of CAR T cell therapy in multiple myeloma

Chimeric antigen receptor (CAR) T cell therapy has transformed the treatment landscape of relapsed/refractory multiple myeloma. The current Food and Drug Administration approved CAR T cell therapies idecabtagene vicleucel and ciltacabtagene autoleucel both target B cell maturation antigen (BCMA), which is expressed on the surface of malignant plasma cells. Despite deep initial responses in most patients, relapse after anti-BCMA CAR T cell therapy is common. Investigations of acquired resistance to anti-BCMA CAR T cell therapy are underway. Meanwhile, other viable antigenic targets are being pursued, including G protein-coupled receptor class C group 5 member D (GPRC5D), signaling lymphocytic activation molecule family member 7 (SLAMF7), and CD38, among others. CAR T cells targeting these antigens, alone or in combination with anti-BCMA approaches, appear to be highly promising as they move from preclinical studies to early phase clinical trials. This review summarizes the current data with novel CAR T cell targets beyond BCMA that have the potential to enter the treatment landscape in the near future.

SOHO State of the Art Updates and Next Questions: Will CAR-T Replace ASCT in NDMM

The treatment landscape for multiple myeloma (MM) has rapidly evolved over the last 2 decades. The development of triplet and quadruplet regimens including proteasome inhibitors (PI), immunomodulatory agents (IMiDs), and anti-CD38 monoclonal antibodies has dramatically extended overall survival. In addition to effective multidrug regimens, autologous stem cell transplant (ASCT) is a cornerstone of management in newly diagnosed multiple myeloma (NDMM). However, despite these combined treatment modalities, curative therapy for MM remains elusive. Recent, novel immunotherapies including chimeric antigen T-cell (CAR-T) therapy have demonstrated deep and durable responses in relapsed and refractory multiple myeloma (RRMM). Currently 2 CAR-T products, ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), are approved by the FDA for the treatment of RRMM. The success of CAR-T therapy revolutionized the management of RRMM prompting clinical trials studying CAR-T therapy in the first line setting. The ongoing KarMMa-4, CARTITUDE-5, and CARTITUDE-6 clinical trials may establish CAR-T therapy as a first line option potentially supplanting ASCT in the initial treatment of NDMM. In this review, we discuss the current standard of care management of NDMM, trace the evolution of CAR-T clinical trials in RRMM, and survey ongoing clinical trials studying CAR-T therapy in NDMM.

25-hydroxycholesterol promotes proliferation and metastasis of lung adenocarcinoma cells by regulating ERβ/TNFRSF17 axis

Lung adenocarcinoma is the main type of lung cancer in women. Our previous findings have evidenced that 25-hydroxycholesterol (25-HC) promotes migration and invasion of lung adenocarcinoma cells (LAC), during which LXR as a 25-HC receptor plays an important role. Estrogen receptor beta (ERβ) is a receptor of 27-hydroxycholesterol that is structurally analogous to 25-HC, but its role in the functional actions of 25-HC remained largely unknown. In this study, we demonstrated that 25-HC treatment triggered ERβ expression in LAC. Knockdown of ERβ inhibited 25-HC-mediated proliferation, migration and invasion, and reduced 25-HC-induced LAC metastasis in vivo. Further investigation revealed that ERβ knockdown restrained the expression of TNFRSF17 (BCMA). In vivo experiments also confirmed that ERβ knockdown blocked 25-HC-induced TNFRSF17 expression. TNFRSF17 knockdown also restrained 25-HC-induced proliferation, migration and invasion. Bioinformatic analysis showed that the levels of ERβ and TNFRSF17 were elevated in lung adenocarcinoma, and were closely related to tumor stages and nodal metastasis status. These results suggested that 25-HC promoted the proliferation and metastasis of LAC by regulating ERβ/TNFRSF17 axis.

Identification and validation of a costimulatory molecule-related signature to predict the prognosis for uveal melanoma patients

Uveal melanoma (UVM) is the most common primary tumor in adult human eyes. Costimulatory molecules (CMs) are important in maintaining T cell biological functions and regulating immune responses. To investigate the role of CMs in UVM and exploit prognostic signature by bioinformatics analysis. This study aimed to identify and validate a CMs associated signature and investigate its role in the progression and prognosis of UVM. The expression profile data of training cohort and validation cohort were downloaded from The Cancer Genome Atlas (TCGA) dataset and the Gene Expression Omnibus (GEO) dataset. 60 CM genes were identified, and 34 genes were associated with prognosis by univariate Cox regression. A prognostic signature was established with six CM genes. Further, high- and low-risk groups were divided by the median, and Kaplan-Meier (K-M) curves indicated that high-risk patients presented a poorer prognosis. We analyzed the correlation of gender, age, stage, and risk score on prognosis by univariate and multivariate regression analysis. We found that risk score was the only risk factor for prognosis. Through the integration of the tumor immune microenvironment (TIME), it was found that the high-risk group presented more immune cell infiltration and expression of immune checkpoints and obtained higher immune scores. Enrichment analysis of the biological functions of the two groups revealed that the differential parts were mainly related to cell-cell adhesion, regulation of T-cell activation, and cytokine-cytokine receptor interaction. No differences in tumor mutation burden (TMB) were found between the two groups. GNA11 and BAP1 have higher mutation frequencies in high-risk patients. Finally, based on the Genomics of Drug Sensitivity in Cancer 2 (GDSC2) dataset, drug sensitivity analysis found that high-risk patients may be potential beneficiaries of the treatment of crizotinib or temozolomide. Taken together, our CM-related prognostic signature is a reliable biomarker that may provide ideas for future treatments for the disease.

Endogenous CD28 drives CAR T cell responses in multiple myeloma

Recent FDA approvals of chimeric antigen receptor (CAR) T cell therapy for multiple myeloma (MM) have reshaped the therapeutic landscape for this incurable cancer. In pivotal clinical trials B cell maturation antigen (BCMA) targeted, 4-1BB co-stimulated (BBζ) CAR T cells dramatically outperformed standard-of-care chemotherapy, yet most patients experienced MM relapse within two years of therapy, underscoring the need to improve CAR T cell efficacy in MM. We set out to determine if inhibition of MM bone marrow microenvironment (BME) survival signaling could increase sensitivity to CAR T cells. In contrast to expectations, blocking the CD28 MM survival signal with abatacept (CTLA4-Ig) accelerated disease relapse following CAR T therapy in preclinical models, potentially due to blocking CD28 signaling in CAR T cells. Knockout studies confirmed that endogenous CD28 expressed on BBζ CAR T cells drove in vivo anti-MM activity. Mechanistically, CD28 reprogrammed mitochondrial metabolism to maintain redox balance and CAR T cell proliferation in the MM BME. Transient CD28 inhibition with abatacept restrained rapid BBζ CAR T cell expansion and limited inflammatory cytokines in the MM BME without significantly affecting long-term survival of treated mice. Overall, data directly demonstrate a need for CD28 signaling for sustained in vivo function of CAR T cells and indicate that transient CD28 blockade could reduce cytokine release and associated toxicities.

BCMA-targeting chimeric antigen receptor T cell therapy for relapsed and/or refractory multiple myeloma

Recently, many new therapies have improved the outcomes of patients with relapsed and/or refractory multiple myeloma (RRMM). Nevertheless, recurrence is still unavoidable, and better treatment choices for RRMM are urgently needed. The clinical success of Chimera antigen receptor (CAR) T cell therapy in many hematological diseases, including leukemia and lymphoma, has drawn considerable attention to RRMM. As CAR T cell therapy continues to mature and challenge traditional therapies, it is gradually changing the treatment paradigm for MM patients. The B cell maturation antigen (BCMA), expressed in malignant plasma cells but not normal ones, is an ideal target for MM treatment, due to its high expression. The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) has approved two BCMA-targeting CAR T cell products, idecabtagene vicleucel (Ide-cel) and ciltacabtagene autoleucel (Cilta-cel), for use in RRMM. In this review, we focus on data from RRMM patients involved in clinical trials of Ide-cel and Cilta-cel and discuss the present situation and future direction of CAR T cell therapy for this condition.

Bispecific Antibodies in the Treatment of Multiple Myeloma

The treatment of multiple myeloma (MM) is evolving rapidly. In recent years, T-cell-based novel immunotherapies emerged as new treatment strategies for patients with relapsed/refractory MM, including highly effective new options like chimeric antigen receptor (CAR)-modified T cells and bispecific antibodies (bsAbs). Currently, B-cell maturation antigen is the most commonly used target antigen for CAR T-cell and bsAb therapies in MM. Results from different clinical trials have demonstrated promising efficacy and acceptable safety profile of bsAb in RRMM.

Delivery of CD47-SIRPα checkpoint blocker by BCMA-directed UCAR-T cells enhances antitumor efficacy in multiple myeloma

In the treatment of relapsed or refractory multiple myeloma patients, BCMA-directed autologous CAR-T cells have showed excellent anti-tumor activity. However, their widespread application is limited due to the arguably cost and time-consuming. Multiple myeloma cells highly expressed CD47 molecule and interact with the SIRPα ligand on the surface of macrophages, in which evade the clearance of macrophages through the activation of "don't eat me" signal. In this study, a BCMA-directed universal CAR-T cells, BC404-UCART, secreting a CD47-SIRPα blocker was developed using CRISPR/Cas9 gene-editing system. BC404-UCART cells significantly inhibited tumor growth and prolonged the survival of mice in the xenograft model. The anti-tumor activity of BC404-UCART cells was achieved via two mechanisms, on the one hand, the UCAR-T cells directly killed tumor cells, on the other hand, the BC404-UCART cells enhanced the phagocytosis of macrophages by secreting anti-CD47 nanobody hu404-hfc fusion that blocked the "don't eat me" signal between macrophages and tumor cells, which provides a potential strategy for the development of novel "off-the-shelf" cellular immunotherapies for the treatment of multiple myeloma.

Autologous hematopoietic stem cell transplantation for multiple myeloma in the age of CAR T cell therapy

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the management of relapsed and refractory myeloma, with excellent outcomes and a tolerable safety profile. High dose chemotherapy with autologous hematopoietic stem cell transplantation (AHCT) is established as a mainstream of newly diagnosed multiple myeloma (NDMM) management in patients who are young and fit enough to tolerate such intensity. This standard was developed based on randomized trials comparing AHCT to chemotherapy in the era prior to novel agents. More recently, larger studies have primarily shown a progression free survival (PFS) benefit of upfront AHCT, rather than overall survival (OS) benefit. There is debate about the significance of this lack of OS, acknowledging the potential confounders of the chronic nature of the disease, study design and competing harms and benefits of exposure to AHCT. Indeed upfront AHCT may not be as uniquely beneficial as we once thought, and is not without risk. New quadruple-agent regimens are highly active and effective in achieving a deep response as quantified by measurable residual disease (MRD). The high dose chemotherapy administered with AHCT imposes a burden of short and long-term adverse effects, which may alter the disease course and patient's ability to tolerate future therapies. Some high-risk subgroups may have a more valuable benefit from AHCT, though still ultimately suffer poor outcomes. When compared to the outcomes of CAR T cell therapy, the question of whether AHCT can or indeed should be deferred has become an important topic in the field. Deferring AHCT may be a personalized decision in patients who achieve MRD negativity, which is now well established as a key prognostic factor for PFS and OS. Reserving or re-administering AHCT at relapse is feasible in many cases and holds the promise of resetting the T cell compartment and opening up options for immune reengagement. It is likely that personalized MRD-guided decision making will shape how we sequence in the future, though more studies are required to delineate when this is safe and appropriate.

Bone marrow inflammation in haematological malignancies

Tissue inflammation is a hallmark of tumour microenvironments. In the bone marrow, tumour-associated inflammation impacts normal niches for haematopoietic progenitor cells and mature immune cells and supports the outgrowth and survival of malignant cells residing in these niche compartments. This Review provides an overview of our current understanding of inflammatory changes in the bone marrow microenvironment of myeloid and lymphoid malignancies, using acute myeloid leukaemia and multiple myeloma as examples and highlights unique and shared features of inflammation in niches for progenitor cells and plasma cells. Importantly, inflammation exerts profoundly different effects on normal bone marrow niches in these malignancies, and we provide context for possible drivers of these divergent effects. We explore the role of tumour cells in inflammatory changes, as well as the role of cellular constituents of normal bone marrow niches, including myeloid cells and stromal cells. Integrating knowledge of disease-specific dynamics of malignancy-associated bone marrow inflammation will provide a necessary framework for future targeting of these processes to improve patient outcome.

BCMA-directed therapy, new treatments in the myeloma toolbox, and how to use them

To address the dearth of therapeutic options available for relapsed-refractory multiple myeloma (RRMM), attention has shifted to immunotherapeutic strategies, with most products in development targeting the B-cell maturation antigen (BCMA). BCMA is a transmembrane receptor of the tumor necrosis factor receptor superfamily, essential for plasma cell survival and minimally expressed on non-hematopoietic tissues; it represents an ideal therapeutic target. Three categories of BCMA-directed therapies exist, with distinct strengths and weaknesses. Antibody-drug conjugates (ADCs) are immediately available with modest single-agent efficacy in RRMM, but deliverability is hampered by corneal toxicity. CAR T-cells are the most effective class but face significant logistical and financial barriers. Bispecific antibodies offer superior efficacy and tolerability compared to ADCs, but prolonged exposure causes significant cumulative infectious risk. In this review, we will examine the role of BCMA in MM biology, the approved and emerging therapies targeting this antigen, and how these agents can be optimally sequenced.

Identification of an angiogenesis-related risk score model for survival prediction and immunosubtype screening in multiple myeloma

BACKGROUND

Multiple myeloma (MM) is an incurable B-cell malignancy, but with the emergence of immunotherapy, a potential cure is hopeful. The individualized interaction between the tumor and bone marrow (BM) microenvironment determines the response to immunotherapy. Angiogenesis is a constant hallmark of the BM microenvironment in MM. However, little is known about the potency ability of angiogenesis-associated genes (AAGs) to regulate the immune microenvironment of MM patients.

METHODS

We comprehensively dissected the associations between angiogenesis and genomic landscapes, prognosis, and the immune microenvironment by integrating 36 AAGs. Immunohistochemistry was performed to verify the correlation between angiogenic factor expression and patient prognosis. Single-sample gene set enrichment analysis was applied to quantify the relative abundance of 28 infiltrating cells. The AAG score was constructed using the least absolute shrinkage and selection operator Cox regression model.

RESULTS

Angiogenesis was closely correlated with MM patient prognosis, and the mutation intensity of the AAGs was low. Immunohistochemistry confirmed that high microvessel density predicted poor prognosis. Three AAG clusters and two gene clusters with distinct clinical outcomes and immune characteristics were identified. The established AAG_score model performed well in predicting patient prognosis and active immunotherapy response. The high-AAG_score subgroup was characterized by reduced immune cell infiltration, poor prognosis, and inactive immunotherapy response. Multivariate analyses indicated that the AAG_score was strongly robust and independent among the prognostic variables.

CONCLUSION

This study revealed that angiogenesis is significantly related to MM patient prognosis and immune phenotype. Evaluating the AAG signature was conducive to predicting patient response to immunotherapy and guiding more efficacious immunotherapy strategies.

New Biological Therapies for Multiple Myeloma

Multiple myeloma is a cancer of bone marrow plasma cells that represents approximately 10% of hematologic malignancies. Though it is typically incurable, a remarkable suite of new therapies developed over the last 25 years has enabled durable disease control in most patients. This article briefly introduces the clinical features of multiple myeloma and aspects of multiple myeloma biology that modern therapies exploit. Key current and emerging treatment modalities are then reviewed, including cereblon-modulating agents, proteasome inhibitors, monoclonal antibodies, other molecularly targeted therapies (selinexor, venetoclax), chimeric antigen receptor T cells, T cell-engaging bispecific antibodies, and antibody-drug conjugates. For each modality, mechanism of action and clinical considerations are discussed. These therapies are combined and sequenced in modern treatment pathways, discussed at the conclusion of the article, which have led to substantial improvements in outcomes for multiple myeloma patients in recent years.

In Vitro Functionality and Endurance of GMP-Compliant Point-of-Care BCMA.CAR-T Cells at Different Timepoints of Cryopreservation

The search for target antigens for CAR-T cell therapy against multiple myeloma defined the B-cell maturation antigen (BCMA) as an interesting candidate. Several studies with BCMA-directed CAR-T cell therapy showed promising results. Second-generation point-of-care BCMA.CAR-T cells were manufactured to be of a GMP (good manufacturing practice) standard using the CliniMACS Prodigy® device. Cytokine release in BCMA.CAR-T cells after stimulation with BCMA positive versus negative myeloma cell lines, U266/HL60, was assessed via intracellular staining and flow cytometry. The short-term cytotoxic potency of CAR-T cells was evaluated by chromium-51 release, while the long-term potency used co-culture (3 days/round) at effector/target cell ratios of 1:1 and 1:4. To evaluate the activation and exhaustion of CAR-T cells, exhaustion markers were assessed via flow cytometry. Stability was tested through a comparison of these evaluations at different timepoints: d0 as well as d + 14, d + 90 and d + 365 of cryopreservation. As results, (1) Killing efficiency of U266 cells correlated with the dose of CAR-T cells in a classical 4 h chromium-release assay. There was no significant difference after cryopreservation on different timepoints. (2) In terms of endurance of BCMA.CAR-T cell function, BCMA.CAR-T cells kept their ability to kill all tumor cells over six rounds of co-culture. (3) BCMA.CAR-T cells released high amounts of cytokines upon stimulation with tumor cells. There was no significant difference in cytokine release after cryopreservation. According to the results, BCMA.CAR-T cells manufactured under GMP conditions exerted robust and specific killing of target tumor cells with a high release of cytokines. Even after 1 year of cryopreservation, cytotoxic functions were maintained at the same level. This gives clinicians sufficient time to adjust the timepoint of BCMA.CAR-T cell application to the patient's course of the underlying disease.

Antigen-induced chimeric antigen receptor multimerization amplifies on-tumor cytotoxicity

Ligand-induced receptor dimerization or oligomerization is a widespread mechanism for ensuring communication specificity, safeguarding receptor activation, and facilitating amplification of signal transduction across the cellular membrane. However, cell-surface antigen-induced multimerization (dubbed AIM herein) has not yet been consciously leveraged in chimeric antigen receptor (CAR) engineering for enriching T cell-based therapies. We co-developed ciltacabtagene autoleucel (cilta-cel), whose CAR incorporates two B-cell maturation antigen (BCMA)-targeted nanobodies in tandem, for treating multiple myeloma. Here we elucidated a structural and functional model in which BCMA-induced cilta-cel CAR multimerization amplifies myeloma-targeted T cell-mediated cytotoxicity. Crystallographic analysis of BCMA-nanobody complexes revealed atomic details of antigen-antibody hetero-multimerization whilst analytical ultracentrifugation and small-angle X-ray scattering characterized interdependent BCMA apposition and CAR juxtaposition in solution. BCMA-induced nanobody CAR multimerization enhanced cytotoxicity, alongside elevated immune synapse formation and cytotoxicity-mediating cytokine release, towards myeloma-derived cells. Our results provide a framework for contemplating the AIM approach in designing next-generation CARs.

Chimeric Antigen Receptor T Cells in Multiple Myeloma

Multiple myeloma is the second most common hematological malignancy with an approximate incidence of up to 8.5 cases per 100,000 persons per year. Over the last decade, therapy for multiple myeloma has undergone a revolutionary change. Chimeric antigen receptor (CAR) T-cell therapy has played a major role in this evolution. In this review, we discuss the existing state of CAR T-cell therapy in myeloma while evaluating several newer therapies and targets expected in the near future.

Enhanced antitumor efficacy, proliferative capacity, and alleviation of T cell exhaustion by fifth-generation chimeric antigen receptor T cells targeting B cell maturation antigen in multiple myeloma

Chimeric antigen receptor (CAR) T cell therapy targeting B cell maturation antigen (BCMA) has been approved for treating multiple myeloma (MM). Some clinical studies reported suboptimal outcomes, including reduced cytotoxicity of CAR-T cells and tumor evasion through increased expression of programmed death-ligand 1 (PD-L1). To enhance CAR-T cell efficiency and overcome PD-L1-mediated T cell suppression, we developed anti-BCMA-CAR5-T cells equipped with three costimulatory domains and the ability to secrete anti-PD-L1 single-chain variable fragment (scFv) blockade molecules. Anti-BCMA-CAR4-T cells contained a fully human anti-BCMA scFv and three intracellular domains (CD28, 4-1BB, and CD27) joined with CD3ζ. Anti-BCMA-CAR5-T cells were generated by fusing anti-BCMA-CAR4 with anti-PD-L1 scFv. Both anti-BCMA-CAR4-T and anti-BCMA-CAR5-T cells demonstrated comparable antitumor activity against parental MM cells. However, at an effector-to-target ratio of 1:2, only anti-BCMA-CAR5-T cells maintained cytolytic activity against PD-L1 high MM cells, unlike anti-BCMA-CAR4 T cells. Anti-BCMA-CAR5-T cells were specifically activated by BCMA-expressing target cells, resulting in increased CAR-T cell proliferation, release of cytolytic mediators, and pro-inflammatory cytokines. Anti-BCMA-CAR5-T cells demonstrated specific cytotoxicity against BCMA-expressing target cells, leading to decreased target cell numbers, increased CAR-T cell numbers, and preserved CAR expression during antigenic re-stimulation. Interestingly, only anti-BCMA-CAR5-T cells showed reduced PD-1 receptor levels, which correlated with decreased PD-L1 expression on target cells. We successfully generated anti-BCMA-CAR5-T cells capable of secreting anti-PD-L1 scFv. These cells exhibited superior antitumor efficiency, proliferative capacity, and alleviated T-cell exhaustion against MM cells. Further investigation into the antitumor efficacy of anti-BCMA-CAR5-T cells is warranted in ex vivo and clinical research settings.

CAR-T-Cell Therapy in Multiple Myeloma: B-Cell Maturation Antigen (BCMA) and Beyond

Significant progress has been achieved in the realm of therapeutic interventions for multiple myeloma (MM), leading to transformative shifts in its clinical management. While conventional modalities such as surgery, radiotherapy, and chemotherapy have improved the clinical outcomes, the overarching challenge of effecting a comprehensive cure for patients afflicted with relapsed and refractory MM (RRMM) endures. Notably, adoptive cellular therapy, especially chimeric antigen receptor T-cell (CAR-T) therapy, has exhibited efficacy in patients with refractory or resistant B-cell malignancies and is now also being tested in patients with MM. Within this context, the B-cell maturation antigen (BCMA) has emerged as a promising candidate for CAR-T-cell antigen targeting in MM. Alternative targets include SLAMF7, CD38, CD19, the signaling lymphocyte activation molecule CS1, NKG2D, and CD138. Numerous clinical studies have demonstrated the clinical efficacy of these CAR-T-cell therapies, although longitudinal follow-up reveals some degree of antigenic escape. The widespread implementation of CAR-T-cell therapy is encumbered by several barriers, including antigenic evasion, uneven intratumoral infiltration in solid cancers, cytokine release syndrome, neurotoxicity, logistical implementation, and financial burden. This article provides an overview of CAR-T-cell therapy in MM and the utilization of BCMA as the target antigen, as well as an overview of other potential target moieties.

Differential Diagnosis and Therapeutic Advances in Multiple Myeloma: A Review Article

Multiple myeloma (MM) is a hematologic malignancy characterized by the abnormal clonal proliferation of plasma cells that may result in focal bone lesions, renal failure, anemia, and/or hypercalcemia. Recently, the diagnosis and treatment of MM have evolved due to a better understanding of disease pathophysiology, improved risk stratification, and new treatments. The incorporation of new drugs, including proteasome inhibitors, immunomodulatory drugs, anti-CD38 antibodies and high-dose chemotherapy followed by hematopoietic stem cell transplantation, has resulted in a significant improvement in patient outcomes and QoL. In this review, we summarize differential diagnoses and therapeutic advances in MM.

Idecabtagene vicleucel for relapsed and refractory multiple myeloma: post hoc 18-month follow-up of a phase 1 trial

Idecabtagene vicleucel (ide-cel) is a B-cell-maturation antigen (BCMA)-directed chimeric antigen receptor T cell therapy. We performed a post hoc analysis of a single-arm phase 1 multicenter study in relapsed/refractory multiple myeloma (CRB-401) (n = 62; median follow-up, 18.1 months). The primary endpoint was safety outcomes, and secondary endpoints included overall response rate (ORR), complete response (CR) and very good partial response (VGPR). The study met its primary endpoint with low rates of grade 3/grade 4 cytokine release syndrome (6.5%) and neurotoxicity (1.6%). ORR was 75.8%; 64.5% achieved VGPR or better and 38.7% achieved CR or stringent CR. Among exploratory endpoints, median duration of response, progression-free survival (PFS) and overall survival were 10.3, 8.8 and 34.2 months, respectively, and ide-cel expansion in blood and bone marrow correlated with clinical efficacy and postinfusion reduction of soluble BCMA. Patients with PFS ≥ 18 months had more naive and less exhausted T cells in apheresis material and improved functional T cell phenotype in the drug product compared with those with less durable responses. These results confirm ide-cel safety, tolerability and efficacy and describe T cell qualities that correlate with durable response. Clinicaltrials.gov identifier : NCT02658929 .

SLAMF7 as a Promising Immunotherapeutic Target in Multiple Myeloma Treatments

Multiple myeloma (MM) is a common hematological malignancy that has fostered several new therapeutic approaches to combat newly diagnosed or relapsed MM. While the field has advanced over the past 2 decades, the majority of patients will develop resistance to these treatments, causing the need for new therapeutic targets. SLAMF7 is an attractive therapeutic target in multiple myeloma, and a monoclonal antibody that targets SLAMF7 has shown consistent beneficial outcomes in clinical trials to date. In this review, we will focus on the structure and regulation of SLAMF7 and its mechanism of action. The most recent clinical trials will be reviewed to further understand the clinical implications and improve the prognosis of MM. Furthermore, the efficacy of anti-SLAMF7 monoclonal antibodies combined with standard therapies and possible resistance mechanisms will be discussed. This review aimed to provide a detailed summary of the role of SLAMF7 in the pathogenesis of patients with MM and the rationale for further investigation into SLAMF7-mediated molecular pathways associated with MM development.

Management of Adverse Reactions for BCMA-Directed Therapy in Relapsed Multiple Myeloma: A Focused Review

Anti-B-cell maturation antigen therapies consisting of bispecific antibodies, antibody-drug conjugates, and chimeric antigen receptor T cells have shown promising results in relapsed refractory multiple myeloma (RRMM). However, the severe side effects include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cytopenia(s), infections, hemophagocytic lymphohistiocytosis, and organ toxicity, which could sometimes be life-threatening. This review focuses on these most common complications post-BCMA therapy. We discussed the risk factors, pathogenesis, clinical features associated with these complications, and how to prevent and treat them. We included four original studies for this focused review. All four agents (idecabtagene vicleucel, ciltacabtagene autoleucel, teclistamab, belantamab mafodotin) have received FDA approval for adult RRMM patients. We went through the FDA access data packages of the approved agents to outline stepwise management of the complications for better patient outcomes.

Resolving the spatial architecture of myeloma and its microenvironment at the single-cell level

In multiple myeloma spatial differences in the subclonal architecture, molecular signatures and composition of the microenvironment remain poorly characterized. To address this shortcoming, we perform multi-region sequencing on paired random bone marrow and focal lesion samples from 17 newly diagnosed patients. Using single-cell RNA- and ATAC-seq we find a median of 6 tumor subclones per patient and unique subclones in focal lesions. Genetically identical subclones display different levels of spatial transcriptional plasticity, including nearly identical profiles and pronounced heterogeneity at different sites, which can include differential expression of immunotherapy targets, such as CD20 and CD38. Macrophages are significantly depleted in the microenvironment of focal lesions. We observe proportional changes in the T-cell repertoire but no site-specific expansion of T-cell clones in intramedullary lesions. In conclusion, our results demonstrate the relevance of considering spatial heterogeneity in multiple myeloma with potential implications for models of cell-cell interactions and disease progression.

Cytokine receptor IL27RA is an NF-κB-responsive gene involved in CD38 upregulation in multiple myeloma

Multiple myeloma (MM) shows constitutive activation of canonical and noncanonical nuclear factor κB (NF-κB) signaling via genetic mutations or tumor microenvironment (TME) stimulations. A subset of MM cell lines showed dependency for cell growth and survival on the canonical NF-κB transcription factor RELA alone, suggesting a critical role for a RELA-mediated biological program in MM pathogenesis. Here, we determined the RELA-dependent transcriptional program in MM cell lines and found the expression of the cell surface molecules interleukin-27 receptor-α (IL-27Rα) and the adhesion molecule JAM2 to be responsive to RELA at the messenger RNA and protein levels. IL-27Rα and JAM2 were expressed on primary MM cells at higher levels than on healthy long-lived plasma cells (PCs) in the bone marrow. IL-27 activated STAT1, and to a lesser extent STAT3, in MM cell lines and in PCs generated from memory B cells in an IL-21-dependent in vitro PC differentiation assay. Concomitant activity of IL-21 and IL-27 enhanced differentiation into PCs and increased the cell-surface expression of the known STAT target gene CD38. In accordance, a subset of MM cell lines and primary MM cells cultured with IL-27 upregulated CD38 cell-surface expression, a finding with potential implications for enhancing the efficacy of CD38-directed monoclonal antibody therapies by increasing CD38 expression on tumor cells. The elevated expression of IL-27Rα and JAM2 on MM cells compared with that on healthy PCs may be exploited for the development of targeted therapeutic strategies that modulate the interaction of MM cells with the TME.

Harnessing the potential of CAR-T cell therapy: progress, challenges, and future directions in hematological and solid tumor treatments

Traditional cancer treatments use nonspecific drugs and monoclonal antibodies to target tumor cells. Chimeric antigen receptor (CAR)-T cell therapy, however, leverages the immune system's T-cells to recognize and attack tumor cells. T-cells are isolated from patients and modified to target tumor-associated antigens. CAR-T therapy has achieved FDA approval for treating blood cancers like B-cell acute lymphoblastic leukemia, large B-cell lymphoma, and multiple myeloma by targeting CD-19 and B-cell maturation antigens. Bi-specific chimeric antigen receptors may contribute to mitigating tumor antigen escape, but their efficacy could be limited in cases where certain tumor cells do not express the targeted antigens. Despite success in blood cancers, CAR-T technology faces challenges in solid tumors, including lack of reliable tumor-associated antigens, hypoxic cores, immunosuppressive tumor environments, enhanced reactive oxygen species, and decreased T-cell infiltration. To overcome these challenges, current research aims to identify reliable tumor-associated antigens and develop cost-effective, tumor microenvironment-specific CAR-T cells. This review covers the evolution of CAR-T therapy against various tumors, including hematological and solid tumors, highlights challenges faced by CAR-T cell therapy, and suggests strategies to overcome these obstacles, such as utilizing single-cell RNA sequencing and artificial intelligence to optimize clinical-grade CAR-T cells.

Targeting B Cell Maturation Antigen in Patients with Multiple Myeloma: Current Perspectives

Relapsed/refractory multiple myeloma remains a challenging disease necessitating the development of more effective treatment options. In the past decade, myeloma therapies have made significant advancements with the introduction of new treatment modalities. One of the new major targets for these novel therapeutics has been B-cell maturation antigen (BCMA), which is expressed on mature B-lymphocytes and plasma cells. There are three main categories of BCMA-targeted therapies currently available, including bispecific antibodies (BsAbs), antibody drug conjugates (ADCs), and chimeric antigen receptor (CAR) T-cell therapies. In this review, we discuss the existing BCMA-targeted therapies and provide insights into currently available treatment and future developments, with a particular focus on clinical efficacy and common drug-related adverse events.

3-O sulfation of syndecan-1 mediated by the sulfotransferase HS3ST3a1 enhances myeloma aggressiveness

Multiple myeloma is a hematological neoplasm derived from plasma cells invariably developing in the bone marrow (BM). The persisting clinical challenge in MM resides in its high ability to resist drugs as shown by the frequent relapses observed in patients regardless of the treatment applied. In a mouse model of MM, we identified a subpopulation of cells harboring increased resistance to current MM drugs. These cells bound a proliferation inducing ligand (APRIL), a key MM promoting/survival factor. APRIL binding involved the heparan sulfate (HS) chain present on syndecan-1 (SDC-1), and correlated with reactivity to the anti-HS antibody 10e4. 10e4+cells had a high proliferation activity, and were able to form colonies in 3-D cultures. 10e4+ cells were the only cells able to develop in BM after intravenous injection. They also resisted drugs in vivo, since their number increased after treatment in BM. Notably, 10e4+ cells differentiated into 10e4- cells upon in vitro and in vivo expansion. Expression of one sulfotransferase, HS3ST3a1, allowed modification of syndecan-1 to confer reactivity to 10e4 and binding to APRIL. HS3ST3a1 deletion inhibited tumorigenesis in BM. Notably, the two populations coexisted at a variable frequency in the BM of MM patients at diagnosis. In total, our results indicate that 3-O-sulfation on SDC-1 carried out by HS3ST3a1 defines aggressive MM cells, and that targeting of this enzyme could possibly be used to better control drug resistance.