Bispecific antibodies in the treatment of multiple myeloma

Targeting Active Microglia Alleviates Distal Edge of Proton Radiation-induced Neural Damage

Purpose

Proton therapy (PT) has distinct advantages in its ability to precisely target tumors while avoiding adjacent normal tissues. However, the distal edge effects of PT constrain its application. This study investigated the brain tissue response in the distal edge regions of protons and compared it with the effect of photons.

Methods and Materials

The occurrence of damage from photons and at the distal edge of protons was investigated in a murine model. Bragg peak treatment plans for murine models were optimized. Hematoxylin and eosin and immunofluorescence staining were performed along the distal margin. In addition, the approximate distance from the Bragg peak to the neuronal damage sites was calculated. Furthermore, a small-molecule inhibitor was studied for its ability to inhibit microglia activation.

Results

The distal edge brain injury murine model was successfully established. Reactive gliosis and granulovacuolar neuronal degeneration were observed in the right hemisphere of the brain in the proton irradiation group. Neuronal injuries were observed at multiple locations (the frontal lobe, thalamus, and cerebral cortex) along the distal border, but no injured neurons were detected along vertical photon irradiation exposed areas. Meanwhile, severe neural damage was seen with horizontal photon irradiation. At the distal edge of the Bragg peak (0.4633 ± 0.01856 cm), microglia with abnormal morphology accumulated. IBA1 and CD68 staining revealed activated microglia at the corresponding neuronal damage sites, indicating their involvement in irradiation-induced damage. Activated microglia were not observed with vertical photon irradiation, whereas many activated microglia were observed with horizontal photon irradiation. Moreover, asparagine endopeptidase inhibitors administered via intraperitoneal injection significantly reduced active microglia in the thalamus and cerebral cortex and alleviated brain damage.

Conclusions

This study demonstrated that proton radiation induces neuronal damage and accumulation of activated microglia at the distal edge. Targeting activated microglia may play a protective role in distal edge injury from radiation.

Two-component T-cell immunotherapy enables antigen pre-targeting to reduce cytokine release without forfeiting efficacy

Contemporary T-cell immunotherapies, despite impressive targeting precision, are hindered by aberrant cytokine release and restrictive targeting stoichiometry. We introduce a two-component T-cell immunotherapy targeting B-cell malignancies: Multi-Antigen T-Cell Hybridizers (MATCH). This split antibody technology differs from current therapies by separating cancer cell-targeting components from T cell-engaging components. We demonstrate that this two-component structure facilitates tunable T-cell activation. αCD19 and αCD20 MATCH, administered in two steps, are both compared to the clinical standard bispecific antibody, blinatumomab. In vitro two-dimensional dose analysis and cytokine release data indicate MATCH improves cancer clearance with reduced cytokine release. Cytolytic mechanisms of action are evaluated. αCD20 MATCH anti-cancer efficacy is assayed using a human lymphoma murine model. Decreasing T-cell engager dose 10-fold yields comparable efficacy to non-reduced doses. Ultimately, this split-antibody paradigm may enhance antigen targeting while reducing cytokine release, with such safety and efficacy advantages augmented by the future possibility of multi-antigen targeting with MATCH.

A German multicenter real-world analysis of talquetamab in 138 patients with relapsed/refractory multiple myeloma

Bispecific T-cell engagers (BTCEs) represent a paradigm shift in the treatment of relapsed/refractory multiple myeloma (RRMM). Talquetamab, a GPRC5DxCD3 BTCE, has shown promising results in the MonumenTAL-1 trial and was recently approved by the Food and Drug Administration and the European Medicines Agency. However, treatment under real-world conditions may not represent patient characteristics in clinical trials with restricted enrollment criteria. We performed a retrospective real-world analysis including 138 RRMM patients treated with talquetamab at 21 German centers. Of evaluable patients, 43% had ISS stage III, 37% had extraosseous disease, and 48% had high-risk cytogenetics. After a median of six prior therapy lines, 58% of patients would not have been eligible for MonumenTAL-1. With a median follow-up of 8.2 months, we observed an overall response rate of 65% and a median progression-free survival of 6.4 months (95% confidence interval 5.1-9.0). Prior BTCE exposure, ISS stage III, extraosseous disease, and penta-drug refractory disease were associated with unfavorable outcomes. Grade ≥ 3 cytokine release syndrome and neurotoxicity occurred in 5.1% and 1.5% of patients, respectively. In summary, our real-world study confirms the efficacy and safety of talquetamab, despite a high proportion of patient- and disease-related risk factors. These results support its use as bridging or long-term treatment, even in advanced stages.

Non-relapse mortality with bispecific antibodies: A systematic review and meta-analysis in lymphoma and multiple myeloma

Bispecific antibodies (BsAb) are associated with distinct immune-related toxicities that impact morbidity and mortality. This systematic review and meta-analysis examined non-relapse mortality (NRM) with BsAb therapy in B-cell non-Hodgkin lymphoma (NHL) and multiple myeloma (MM). A PubMed and Embase search up to October 2024 identified 29 studies (21 NHL, 8 MM) involving 2,535 patients. The overall NRM point estimate was 4.7% (95% confidence interval [CI] 3.4%-6.4%), with a median follow-up of 12.0 months. We noted no significant difference in NRM across disease entities (NHL: 4.2%, MM: 6.2%, p = 0.22). In NHL, prespecified subgroup analyses revealed increased NRM in real-world studies compared to clinical trials. For MM, an association between NRM and higher response rates and longer follow-up was noted. Meta-regression comparing BsAb and CAR-T therapies (n = 8,592) showed no significant NRM difference when accounting for key study-level confounders (p = 0.96). Overall, infections were the leading cause of NRM, accounting for 71.8% of non-relapse deaths. Of the infection-related deaths, 48% were attributed to COVID-19. In a pre-specified sensitivity analysis excluding COVID-19 fatalities, the overall NRM estimate was 3.5% (95% CI 2.6%-4.6%). Taken together, these results provide a benchmark for the estimated NRM with BsAb therapy and highlight the paramount importance of infection reporting, prevention, and mitigation.

T-Cell Engagers In Multiple Myeloma: A Clinical Review

T-cell engagers (TCEs) are engineered to bind both the CD3 subunit on T-cells and specific antigens on tumor cells, triggering T-cell activation and tumor cell lysis. TCEs targeting B-cell maturation antigen (BCMA) and G-protein-coupled receptor, class C, group 5, member D (GPRC5D) have demonstrated significant clinical activity in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM). As a monotherapy, TCEs have had overall response rates (ORRs) of over 60%, with deep and durable hematological responses. Common toxicities include cytokine release syndrome (CRS), infections, and on-target off-tumor effects. Ongoing research looks to enhance the efficacy and tolerability of TCEs for the next generation of products to play an even bigger role in treating patients with MM.

An evaluation of linvoseltamab for treatment of relapsed/refractory multiple myeloma

INTRODUCTION

Bispecific antibody therapies, primarily targeting B-cell maturation antigen (BCMA), have shown remarkable outcomes in the treatment of heavily pretreated patients with multiple myeloma (MM). However, there are no current head-to-head trials informing practice for selection or sequencing of optimal T cell redirection strategies in later lines of therapy. Linvoseltamab is a novel BCMA-targeted bispecific antibody that was recently evaluated in the phase 1/2 LINKER-MM1 trial and is currently pending formal regulatory approval.

AREAS COVERED

In this drug evaluation, we review efficacy and toxicity profiles of linvoseltamab in the context of currently approved bispecific antibody therapies for MM. Specifically, we highlight differences in dosing strategy, cytokine release syndrome (CRS) kinetics, and indirect efficacy comparisons between trials of linvoseltamab and other bispecific antibodies.

EXPERT OPINION

Linvoseltamab has a similar efficacy profile with favorable CRS incidence and time-to-onset compared to other approved bispecific antibodies. Pending final regulatory approval and labeling, further real-world analyses are needed to evaluate its final role in the evolving landscape of T cell redirection therapy for MM.

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.

Multiple Myeloma Insights from Single-Cell Analysis: Clonal Evolution, the Microenvironment, Therapy Evasion, and Clinical Implications

Multiple myeloma (MM) is a complex and heterogeneous hematologic malignancy characterized by clonal evolution, genetic instability, and interactions with a supportive tumor microenvironment. These factors contribute to treatment resistance, disease progression, and significant variability in clinical outcomes among patients. This review explores the mechanisms underlying MM progression, including the genetic and epigenetic changes that drive clonal evolution, the role of the bone marrow microenvironment in supporting tumor growth and immune evasion, and the impact of genomic instability. We highlight the critical insights gained from single-cell technologies, such as single-cell transcriptomics, genomics, and multiomics, which have enabled a detailed understanding of MM heterogeneity at the cellular level, facilitating the identification of rare cell populations and mechanisms of drug resistance. Despite the promise of advanced technologies, MM remains an incurable disease and challenges remain in their clinical application, including high costs, data complexity, and the need for standardized bioinformatics and ethical considerations. This review emphasizes the importance of continued research and collaboration to address these challenges, ultimately aiming to enhance personalized treatment strategies and improve patient outcomes in MM.

Outcomes and prognostic indicators in daratumumab-refractory multiple myeloma: a multicenter real-world study of elotuzumab, pomalidomide, and dexamethasone in 247 patients

BACKGROUND

Daratumumab-refractory multiple myeloma (Dara-R MM) presents a significant treatment challenge. This study aimed to evaluate the efficacy and survival outcomes of elotuzumab, pomalidomide, and dexamethasone (EloPd) in a large, real-world cohort of patients with Dara-R MM, with particular focus on progression-free survival (PFS) and overall survival (OS).

MATERIALS AND METHODS

This retrospective analysis included 247 Dara-R MM patients treated with EloPd. All patients were also refractory to lenalidomide, with 51.4% to a proteasome inhibitor, thus classified as triple-class refractory (TCR). Survival risk-scoring systems for PFS (progression-free risk score-PRSDaraR) and OS (survival risk score-SRSDaraR) were developed to stratify patients based on their risk profiles.

RESULTS

The overall response rate was 52.6%, with a median PFS and OS of 6.6 and 17.0 months, respectively. The International Staging System (ISS) stages II and III, low hemoglobin (Hb) levels, the last therapy being daratumumab, and symptomatic relapse were identified as significant independent predictors of shorter PFS in multivariable analysis. In addition to advanced ISS stages, low Hb levels (<10.6 g/dl), symptomatic relapse, and refractory disease exhibited an independent negative impact on OS. Importantly, no significant differences in both PFS and OS were observed between TCR and non-TCR patients. Based on these multivariable analyses, we developed PRSDaraR and SRSDaraR according to the magnitude of the hazard ratio. In PRSDaraR, 10.1% were low-risk, 41.3% intermediate, 43.3% high, and 5.3% very high-risk. The 12-month PFS probabilities were 86.3% (low), 67.6% (intermediate), 52.9% (high), and 31.8% (very high). For SRSDaraR, 6.1% were low-risk, 47.8% intermediate, 19.4% high, and 26.7% very high. The 12-month OS probabilities were 90.9% (low), 75.7% (intermediate), 55.9% (high), and 32.6% (very high).

CONCLUSIONS

This study supports EloPd as an effective treatment option in Dara-R MM patients, providing valuable disease control and acting as a potential bridge to newer therapies, such as CAR-T and bispecific antibodies.

Comprehensive Review of Early and Late Toxicities in CAR T-Cell Therapy and Bispecific Antibody Treatments for Hematologic Malignancies

Chimeric antigen receptor T-cell (or CAR-T) therapy and bispecific antibodies (BsAbs) have revolutionized the treatment of hematologic malignancies, offering new options for relapsed or refractory cases. However, these therapies carry risks of early complications, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), and delayed issues like graft-versus-host disease (GVHD), infections, and secondary cancers. Effective management requires early diagnosis using advanced biomarkers and imaging, along with prompt interventions involving immunosuppressants, corticosteroids, and cytokine inhibitors. A multidisciplinary approach is essential, integrating hematologists, oncologists, and infectious disease specialists, with emerging strategies like targeted biologics and personalized medicine showing promise in balancing efficacy with toxicity management. Ongoing research is critical to refine diagnostics and treatments, ensuring that these therapies not only extend survival but also improve patients’ quality of life. This review provides critical insights for healthcare professionals to quickly recognize and treat complications of CAR-T and BsAbs therapies. By focusing on early detection through biomarkers and imaging and outlining timely therapeutic interventions, it aims to equip the multidisciplinary care team with the knowledge necessary to manage the challenges of these advanced treatments effectively, ultimately optimizing patient outcomes.

Comprehensive Review of Early and Late Toxicities in CAR T-Cell Therapy and Bispecific Antibody Treatments for Hematologic Malignancies

Chimeric antigen receptor T-cell (or CAR-T) therapy and bispecific antibodies (BsAbs) have revolutionized the treatment of hematologic malignancies, offering new options for relapsed or refractory cases. However, these therapies carry risks of early complications, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), and delayed issues like graft-versus-host disease (GVHD), infections, and secondary cancers. Effective management requires early diagnosis using advanced biomarkers and imaging, along with prompt interventions involving immunosuppressants, corticosteroids, and cytokine inhibitors. A multidisciplinary approach is essential, integrating hematologists, oncologists, and infectious disease specialists, with emerging strategies like targeted biologics and personalized medicine showing promise in balancing efficacy with toxicity management. Ongoing research is critical to refine diagnostics and treatments, ensuring that these therapies not only extend survival but also improve patients' quality of life. This review provides critical insights for healthcare professionals to quickly recognize and treat complications of CAR-T and BsAbs therapies. By focusing on early detection through biomarkers and imaging and outlining timely therapeutic interventions, it aims to equip the multidisciplinary care team with the knowledge necessary to manage the challenges of these advanced treatments effectively, ultimately optimizing patient outcomes.