Therapeutic antibodies for multiple myeloma

Immunotherapy of Multiple Myeloma: Current Status as Prologue to the Future

The landscape of therapeutic measures to treat multiple myeloma has undergone a seismic shift since the dawn of the current century. This has been driven largely by the introduction of new classes of small molecules, such as proteasome blockers (e.g., bortezomib) and immunomodulators (e.g., lenalidomide), as well as by immunotherapeutic agents starting with the anti-CD38 monoclonal antibody daratumumab in 2015. Recently, other immunotherapies have been added to the armamentarium of drugs available to fight this malignancy. These include the bispecifics teclistamab, talquetamab, and elranatamab, and the chimeric antigen receptor (CAR) T-cell products idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel). While the accumulated benefits of these newer agents have resulted in a more than doubling of the disease's five-year survival rate to nearly 60% and improved quality of life, the disease remains incurable, as patients become refractory to the drugs and experience relapse. This review covers the current scope of antimyeloma immunotherapeutic agents, both those in clinical use and in development. Included in the discussion are additional monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), bi- and multitargeted mAbs, and CAR T-cells and emerging natural killer (NK) cells, including products intended for "off-the-shelf" (allogeneic) applications. Emphasis is placed on the benefits of each along with the challenges that need to be surmounted if MM is to be cured.

Mental foramen in panoramic radiography can be a reference for discrimination of punched-out lesions in the mandible in patients with symptomatic multiple myeloma: A cross-sectional study

Multiple myeloma (MM) is a hematopoietic malignancy characterized by monoclonal proliferation of plasma cells. MM features bony radiolucencies called punched-out lesions (POLs), which require appropriate diagnosis due to increased risk of surgically-related adverse events. Although dental surgeons can identify dental focal infections (DFIs) in MM patients, the prevalence and characteristics of POLs in the jawbone of MM patients have not been investigated. We examined the prevalence of POLs in the mandible of MM patients, evaluated its relationship with MM International Staging System progression, and examined panoramic radiographs as a diagnostic reference for POLs in a single center in Japan. We identified 98 patients (55 men, 43 women) with a median age of 63 (range, 34 to 91) years. Of these, 18 patients (18.4%) had POLs in the mandible, including two patients in stage I (2/37; 5.4%), six in stage II (6/43; 14.0%), and ten in stage III (10/18; 55.6%). The prevalence of POLs significantly increased with MM stage progression (p < 0.0001). POLs confirmed on computed tomography (CT) were also detected on panoramic radiographs. The Hounsfield unit value at the site of POLs was nearly the same or lower than that of the mental foramen. Although the prevalence of POLs in the mandible is low, dental surgeons need to differentiate POLs as radiological findings when examining DFIs in MM patients. Confirmation of POLs in the mandible is possible by CT and panoramic radiography, and the mental foramen is likely to be a reference for discrimination.

Use of a Daratumumab-Specific Immunofixation Assay to Assess Possible Immunotherapy Interference at a Major Cancer Center: Our Experience and Recommendations

BACKGROUND

The incorporation of monoclonal antibodies, such as daratumumab, into multiple myeloma treatment regimens has led to the issue of false-positive interference in both serum protein electrophoresis (SPEP) and immunofixation (IF). The Hydrashift assay removes daratumumab interference from IF, allowing for correct interpretation. Here, we retrospectively examined the use of the Hydrashift assay at a large cancer center and provide guidelines on its most appropriate use.

METHODS

38 patients with distinct daratumumab peaks on their SPEP were selected and were used to quantify the daratumumab peak on SPEP using the Sebia Phoresis software. A retrospective review of all Hydrashift assays ordered at our institution from July 2018 to March 2020 was performed. Data collected included patient clone type, IF migration patterns, and Hydrashift result. Serial quantification of SPEP results was performed as the corresponding IF transitioned from a true positive to a false positive.

RESULTS

Daratumumab adds a maximum magnitude of 0.20 g/dL on SPEP. Serial SPEP quantification showed IF transitioned from true positive to false positive when M-spikes ranged from 0.09 g/dL to 0.11 g/dL. Over 20 months, our laboratory performed 280 Hydrashift assays on 96 patients, 43/96 of whom had comigrating daratumumab/IgG-K IF bands.

CONCLUSIONS

The Hydrashift assay is typically unnecessary in patients with large M-spikes, >0.25 g/dL, regardless of clone type. When patient history is available, we recommend the Hydrashift assay be used in patients with comigrating daratumumab/IgG-K bands with M-spikes of <0.25 g/dL.

Potent preclinical activity of HexaBody-DR5/DR5 in relapsed and/or refractory multiple myeloma

Apoptosis induction by death receptor (DR)-specific agonistic antibodies is a potentially effective antitumor therapy. Nonetheless, to date, all conventional DR-targeting antibodies that induce apoptosis via FcγR-dependent DR clustering failed to show clinical efficacy. HexaBody-DR5/DR5 (GEN1029) has been developed to overcome full FcγR dependence. HexaBody-DR5/DR5 is a mixture of 2 noncompeting DR5-specific immunoglobulin G1 (IgG1) antibodies, each with an E430G mutation in the Fc domain. This mutation enhances Fc-Fc interactions, resulting in antibody hexamerization, followed by FcγR-independent clustering of DR5 molecules. This unique combination of dual epitope targeting and increased IgG hexamerization resulted in potent preclinical antitumor activity in various solid cancers. In this study, we explored the preclinical activity of HexaBody-DR5/DR5 in multiple myeloma (MM), because MM cells are known to express DR5. In bone marrow samples from 48 MM patients, HexaBody-DR5/DR5 induced potent cytotoxicity of primary MM cells. Importantly, HexaBody-DR5/DR5 mediated the highest cytotoxic activity in samples from relapsed/refractory MM patients, including those who are refractory to daratumumab. This improved cytotoxic activity was observed only in patients who received their last anti-MM treatment <1 month ago, suggesting that anti-MM drugs sensitized MM cells to HexaBody-DR5/DR5. Supporting this, bortezomib combined with HexaBody-DR5/DR5 synergistically increased cytotoxicity in MM cells in 7 of 11 newly diagnosed patients. Lenalidomide also synergized with HexaBody-DR5/DR5, but only via its immunomodulatory effects, presumably by enhancing the antibody-dependent cellular cytotoxicity activity of HexaBody-DR5/DR5. Daratumumab showed additive effects when combined with HexaBody-DR5/DR5. In conclusion, the results of this preclinical study indicate a therapeutic potential for HexaBody-DR5/DR5, especially in recently treated relapsed/refractory MM patients.

Cyclopamine sensitizes multiple myeloma cells to circularly permuted TRAIL-induced apoptosis

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a promising anti-myeloma drug prototype. The aim of the present study was to investigate the synergistic effects of cyclopamine and circularly permuted TRAIL (CPT) on the proliferation and apoptosis of multiple myeloma cells. The results showed that the inhibitory effects of cyclopamine on the proliferation of human myeloma RPMI-8226 and SKO-007 cells were weak. RPMI-8226 cells were sensitive to CPT; however, the proliferation of SKO-007 cells was not effectively inhibited by CPT. SKO-007 cells were thus considered resistant to cyclopamine and CPT and used for subsequent experiments. Treatment with a combination of cyclopamine and CPT significantly inhibited cell proliferation. Moreover, the Q value showed that cyclopamine combined with CPT could synergistically inhibit the proliferation of SKO-007 cells. Cyclopamine increased CPT-induced apoptosis in the SKO-007 cells and exhibited a synergistic induction of apoptosis when combined with CPT. Moreover, the combination of cyclopamine and CPT decreased the ratio of myeloma stem cells. Quantitative PCR showed that cyclopamine decreased the mRNA expression levels of GLI1/GLI2/GLI3 and increased the expression levels of death receptor 4. In conclusion, the present study showed that a combination of cyclopamine and CPT exhibited synergistic effects on the inhibition of proliferation and induction of apoptosis in myeloma cells.

Immunotherapeutic and Targeted Approaches in Multiple Myeloma

The multiple myeloma (MM) therapeutic landscape has evolved significantly with the approval of numerous novel agents, including next generation proteasome inhibitors (PIs), immunomodulatory agents (IMIDs), and monoclonal antibodies (MoABs) targeting CD38 and SLAMF7. While these discoveries have led to an unprecedented improval in patient outcomes, the disease still remains incurable. Immunotherapeutic approaches have shown substantial promise in recent studies of chimeric antigen receptor T-cell (CAR T-cell) therapy, bispecific antibodies, and antibody drug conjugates targeting B-cell maturation antigen (BCMA). This review will highlight these novel and targeted therapies in MM, with particular focus on PIs, IMIDs, MoAb and BCMA-directed immunotherapy.

Proteomics-inspired precision medicine for treating and understanding multiple myeloma

Introduction

Remarkable progress in molecular characterization methods has led to significant improvements in how we manage multiple myeloma (MM). The introduction of novel therapies has led to significant improvements in overall survival over the past 10 years. However, MM remains incurable and treatment choice is largely based on outdated risk-adaptive strategies that do not factor in improved treatment outcomes in the context of modern therapies.

Areas covered

This review discusses current risk-adaptive strategies in MM and the clinical application of proteomics in the monitoring of treatment response, disease progression, and minimal residual disease (MRD). We also discuss promising biomarkers of disease progression, treatment response, and chemoresistance. Finally, we will discuss an immunomics-based approach to monoclonal antibody (mAb), vaccine, and CAR-T cell development.

Expert opinion

It is an exciting era in oncology with basic scientific knowledge translating in novel therapeutic approaches to improve patient outcomes. With the advent of effective immunotherapies and targeted therapies, it has become crucial to identify biomarkers to aid in the stratification of patients based on anticipated sensitivity to chemotherapy. As a paradigm of diseases highly dependent on protein homeostasis, multiple myeloma provides the perfect opportunity to investigate the use of proteomics to aid in precision medicine.

Monoclonal Antibody Therapies in Multiple Myeloma: A Challenge to Develop Novel Targets

The treatment options in multiple myeloma (MM) has changed dramatically over the past decade with the development of novel agents such as proteasome inhibitors (PIs); bortezomib and immunomodulatory drugs (IMiDs); thalidomide, and lenalidomide which revealed high efficacy and improvement of overall survival (OS) in MM patients. However, despite these progresses, most patients relapse and become eventually refractory to these therapies. Thus, the development of novel, targeted immunotherapies has been pursued aggressively. Recently, next-generation PIs; carfilzomib and ixazomib, IMiD; pomalidomide, histone deacetylase inhibitor (HDADi); panobinostat and monoclonal antibodies (MoAbs); and elotuzumab and daratumumab have emerged, and especially, combination of mAbs plus novel agents has led to dramatic improvements in the outcome of MM patients. The field of immune therapies has been accelerating in the treatment of hematological malignancies and has also taken center stage in MM. This review focuses on an overview of current status of novel MoAb therapy including bispecific T-cell engager (BiTE) antibody (BsAb), antibody-drug conjugate (ADC), and chimeric antigen receptor (CAR) T cells, in relapsed or refractory MM (RRMM). Lastly, investigational novel MoAb-based therapy to overcome immunotherapy resistance in MM is shown.

Anti-Multiple Myeloma Potential of Secondary Metabolites from Hibiscus sabdariffa

Multiple myeloma (MM) belongs to hematological cancers and its incidence is increasing worldwide. Despite recent advances in its therapy, MM still causes many deaths every year. In fact, current therapies sometimes fail and are associated with severe adverse effects, including neurotoxicity. As a part of our ongoing efforts to discover new potential therapies against MM, we prepared Hibiscus sabdariffa extracts obtained by a microwave-assisted solvent extraction and investigate their activity by in vitro assays on the RPMI-8226 cell line. The bioguided fractionation of the crude ethanolic extract allowed the identification of HsFC as the most effective extract. We assessed cell viability (MTT and Tripan blue test), cell migration (Boyden chamber assay), and neurotoxicity (DRG neurotoxicity assay). The promising results prompted us to further fractionate HsFC and we obtained two molecules effective against RPMI-8226 cells without neurotoxic effects at their active concentrations. Moreover, both compounds are able to significantly reduce cell migration.

Metabolic, Anti-apoptotic and Immune Evasion Strategies of Primary Human Myeloma Cells Indicate Adaptations to Hypoxia

Multiple Myeloma (MM) is an incurable plasma cell malignancy primarily localized within the bone marrow (BM). It develops from a premalignant stage, monoclonal gammopathy of undetermined significance (MGUS), often via an intermediate stage, smoldering MM (SMM). The mechanisms of MM progression have not yet been fully understood, all the more because patients with MGUS and SMM already carry similar initial mutations as found in MM cells. Over the last years, increased importance has been attributed to the tumor microenvironment and its role in the pathophysiology of the disease. Adaptations of MM cells to hypoxic conditions in the BM have been shown to contribute significantly to MM progression, independently from the genetic predispositions of the tumor cells. Searching for consequences of hypoxia-induced adaptations in primary human MM cells, CD138-positive plasma cells freshly isolated from BM of patients with different disease stages, comprising MGUS, SMM, and MM, were analyzed by proteome profiling, which resulted in the identification of 6218 proteins. Results have been made fully accessible via ProteomeXchange with identifier PXD010600. Data previously obtained from normal primary B cells were included for comparative purposes. A principle component analysis revealed three clusters, differentiating B cells as well as MM cells corresponding to less and more advanced disease stages. Comparing these three clusters pointed to the alteration of pathways indicating adaptations to hypoxic stress in MM cells on disease progression. Protein regulations indicating immune evasion strategies of MM cells were determined, supported by immunohistochemical staining, as well as transcription factors involved in MM development and progression. Protein regulatory networks related to metabolic adaptations of the cells became apparent. Results were strengthened by targeted analyses of a selected panel of metabolites in MM cells and MM-associated fibroblasts. Based on our data, new opportunities may arise for developing therapeutic strategies targeting myeloma disease progression.