New monoclonal antibodies on the horizon in multiple myeloma

BCMA in Multiple Myeloma-A Promising Key to Therapy

Despite the discoveries of numerous agents including next generation proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, multiple myeloma (MM) remains an incurable disease. The field of myeloma treatment in refractory or relapsed patients after standard therapy entered a new era due to the B-cell maturation antigen (BMCA) targeted approach. BCMA is a member of the tumor necrosis factor receptor family with high expression in mature B-lymphocytes and plasma cells. Given the understanding of BCMA mechanism of action in MM, BCMA plays a promising role as a therapeutic target. Several clinical trials are underway to evolve the current BCMA targeted treatment concept such as antibody-drug conjugates (ADCs), bispecific T cell engagers (BITEs) and chimeric antigen receptor (CAR) T cell therapy. Current results of representative BCMA trials may close the gap of the unmet clinical need to further improve the outcome of heavily pretreated MM patients with the potency to change the paradigm in newly diagnosed and refractory MM. This comprehensive review will give an update on various BMCA targeted treatment modalities (ADCs, BITEs, CAR T cell therapy) and its existing results on efficacy and safety from preclinical and clinical trials.

Utility of Flow Cytometry and Fluorescence In Situ Hybridization in Follow-up Monitoring of Plasma Cell Myeloma

OBJECTIVES

We sought to investigate the clinical utility of flow cytometry (FC) and fluorescence in situ hybridization (FISH) in the workup of myeloma.

METHODS

We retrospectively reviewed the reports of bone marrow biopsies received for myeloma evaluation between October 2015 and January 2019.

RESULTS

A total of 1,708 biopsy specimens from 469 myeloma patients (mean age, 64.5 years [SD, 9.3]; female, 41.4%) were reviewed. Both FC and FISH had comparable detection rates at the time of initial diagnosis (97.6% vs 98.8%) and for follow-up cases (28.6% vs 28.2%). FC and FISH results were concordant in 98.8% of the initial diagnosis cases and 89.6% of the follow-up cases. The FISH-positive (FISH+)/FC-negative (FC-) discordance and FISH-/FC+ discordance occurred among 81 (5.0%) and 87 (5.4%) follow-up cases. In comparison with all concordant cases, FISH+/FC- discordant cases were more likely to have received treatment with daratumumab (P < .05).

CONCLUSIONS

Plasma cell-enriched FISH and FC have comparable abnormal plasma cell detection rates, and approximately 10% of the follow-up cases have discordant FISH and FC results in which residual disease is detected by only one of these modalities. FISH testing should be considered for cases with negative FC, especially in patients who have received treatment with daratumumab or in cases in which there is concern about specimen adequacy.

Belantamab Mafodotin to Treat Multiple Myeloma: A Comprehensive Review of Disease, Drug Efficacy and Side Effects

Multiple myeloma (MM) is a hematologic malignancy characterized by excessive clonal proliferation of plasma cells. The treatment of multiple myeloma presents a variety of unique challenges due to the complex molecular pathophysiology and incurable status of the disease at this time. Given that MM is the second most common blood cancer with a characteristic and unavoidable relapse/refractory state during the course of the disease, the development of new therapeutic modalities is crucial. Belantamab mafodotin (belamaf, GSK2857916) is a first-in-class therapeutic, indicated for patients who have previously attempted four other treatments, including an anti-CD38 monoclonal antibody, a proteosome inhibitor, and an immunomodulatory agent. In November 2017, the FDA designated belamaf as a breakthrough therapy for heavily pretreated patients with relapsed/refractory multiple myeloma. In August 2020, the FDA granted accelerated approval as a monotherapy for relapsed or treatment-refractory multiple myeloma. The drug was also approved in the EU for this indication in late August 2020. Of note, belamaf is associated with the following adverse events: decreased platelets, corneal disease, decreased or blurred vision, anemia, infusion-related reactions, pyrexia, and fetal risk, among others. Further studies are necessary to evaluate efficacy in comparison to other standard treatment modalities and as future drugs in this class are developed.

Focus on monoclonal antibodies targeting B-cell maturation antigen (BCMA) in multiple myeloma: update 2021

Remarkable advances have been achieved in the treatment of multiple myeloma (MM) in the last decade, which saw targeted immunotherapy, represented by anti-CD38 monoclonal antibodies, successfully incorporated across indications. However, myeloma is still considered curable in only a small subset of patients, and the majority of them eventually relapse. B-cell maturation antigen (BCMA) is expressed exclusively in mature B lymphocytes and plasma cells, and represents an ideal new target for immunotherapy, presented by bispecific antibody (bsAb) constructs, antibody-drug conjugates (ADCs) and chimeric antigen receptor T (CAR-T) cells. Each of them has proved its efficacy with the potential for deep and long-lasting responses as a single agent therapy in heavily pretreated patients. As a result, belantamab mafodotin was approved by the United States Food and Drug Administration for the treatment of relapsed/refractory MM, as the first anti-BCMA agent. In the present review, we focus on monoclonal antibodies targeting BCMA - bsAbs and ADCs. The data from preclinical studies as well as first-in-human clinical trials will be reviewed, together with the coverage of their constructs and mechanisms of action. The present results have laid the groundwork for the ongoing or upcoming clinical trials with combinatory regimens, which have always been a cornerstone in the treatment of MM.

Oncolytic immunotherapy and bortezomib synergy improves survival of refractory multiple myeloma in a preclinical model

The oncolytic reovirus (RV) has demonstrated clinical efficacy and minimal toxicity in a variety of cancers, including multiple myeloma (MM). MM is a malignancy of plasma cells that is considered treatable but incurable because of the 90% relapse rate that is primarily from drug resistance. The systemic nature of MM and the antitumor immunosuppression by its tumor microenvironment presents an ongoing therapeutic challenge. In the present study, we demonstrate that RV synergizes with the standard-of-care MM drug bortezomib (BTZ) and, importantly, enhances its therapeutic potential in therapy-resistant human MM cell lines in vitro. Using the syngeneic Vk*MYC BTZ-resistant immunocompetent transplantable MM murine model, we also demonstrate that mice harboring BTZ-insensitive MM tumors respond to the RV/BTZ combination treatment in terms of decreased tumor burden and improved overall survival (P < .00001). We demonstrate that BTZ augments RV replication in tumor-associated endothelial cells and myeloma cells, leading to enhanced viral delivery and thereby stimulating cytokine release, immune activity, apoptosis, and reduction of the MM-associated immune suppression. We conclude that combined RV/BTZ is an attractive therapeutic strategy with no safety signals for the treatment of MM.

Advances in Antibody–Drug Conjugate Design: Current Clinical Landscape and Future Innovations

The targeted delivery of potent cytotoxic molecules into cancer cells is considered a promising anticancer strategy. The design of clinically effective antibody–drug conjugates (ADCs), in which biologically active drugs are coupled through chemical linkers to monoclonal antibodies, has presented challenges for pharmaceutical researchers. After 30 years of intensive research and development activities, only seven ADCs have been approved for clinical use; two have received fast-track designation and two breakthrough therapy designation from the Food and Drug Administration. There is continued interest in the field, as documented by the growing number of candidates in clinical development. This review aims to summarize the most recent innovations that have been applied to the design of ADCs undergoing early- and late-stage clinical trials. Discovery and rational optimization of new payloads, chemical linkers, and antibody formats have improved the therapeutic index of next-generation ADCs, ultimately resulting in improved clinical benefit for the patients.

ADCs, as Novel Revolutionary Weapons for Providing a Step Forward in Targeted Therapy of Malignancies

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Antibody drug conjugates (ADCs), as potent pharmaceutical trojan horses for cancer treatment, provide superior efficacy and specific targeting along with low risk of adverse reactions compared to traditional chemotherapeutics. In fact, the development of these agents combines the selective targeting capability of monoclonal antibody (mAb) with high cytotoxicity of chemotherapeutics for controlling the neoplastic mass growth. Different ADCs (more than 60 ADCs) in preclinical and clinical trials were introduced in this novel pharmaceutical field. Various design-based factors must be taken into account for improving the functionality of ADC technology, including selection of appropriate target antigen and high binding affinity of fragment (miniaturized ADCs) or full mAbs (preferentially use of humanized or fully human antibodies compared to murine and chimeric ones), use of bispecific antibodies for dual targeting effect, linker engineering and conjugation method efficacy to obtain more controlled drug to antibody ratio (DAR). Challenging issues affecting therapeutic efficacy and safety of ADCs, including bystander effect, on- and off-target toxicities, multi drug resistance (MDR) are also addressed. 4 FDA-approved ADCs in the market, including ADCETRIS ®, MYLOTARG®, BESPONSA ®, KADCYLA®. The goal of the current review is to evaluate the key parameters affecting ADCs development.

Opportunities and Challenges for Antibodies against Intracellular Antigens

Therapeutic antibodies are one most significant advances in immunotherapy, the development of antibodies against disease-associated MHC-peptide complexes led to the introduction of TCR-like antibodies. TCR-like antibodies combine the recognition of intracellular proteins with the therapeutic potency and versatility of monoclonal antibodies (mAb), offering an unparalleled opportunity to expand the repertoire of therapeutic antibodies available to treat diseases like cancer. This review details the current state of TCR-like antibodies and describes their production, mechanisms as well as their applications. In addition, it presents an insight on the challenges that they must overcome in order to become commercially and clinically validated.

Monoclonal Antibodies and Multiple Myeloma: All in All It's Just Another Brick in the Wall?

This commentary offers insight about the recent review by the European Medicines Agency on the approval of daratumumab for the treatment of adult patients with multiple myeloma.

Diagnosis of Plasma Cell Dyscrasias and Monitoring of Minimal Residual Disease by Multiparametric Flow Cytometry

Plasma cell dyscrasia (PCD) is a heterogeneous disease that has seen a tremendous change in outcomes due to improved therapies. Over the past few decades, multiparametric flow cytometry has played an important role in the detection and monitoring of PCDs. Flow cytometry is a high-sensitivity assay for early detection of minimal residual disease (MRD) that correlates well with progression-free survival and overall survival. Before flow cytometry can be effectively implemented in the clinical setting, sample preparation, panel configuration, analysis, and gating strategies must be optimized to ensure accurate results. Current consensus methods and reporting guidelines for MRD testing are discussed.

B-Cell-Activating Factor and the B-Cell Compartment in HIV/SIV Infection

With the goal to design effective HIV vaccines, intensive studies focused on broadly neutralizing antibodies, which arise in a fraction of HIV-infected people. Apart from identifying new vulnerability sites in the viral envelope proteins, these studies have shown that a fraction of these antibodies are produced by self/poly-reactive B-cells. These findings prompted us to revisit the B-cell differentiation and selection process during HIV/SIV infection and to consider B-cells as active players possibly shaping the helper T-cell program within germinal centers (GCs). In this context, we paid a particular attention to B-cell-activating factor (BAFF), a key cytokine in B-cell development and immune response that is overproduced during HIV/SIV infection. As it does in autoimmune diseases, BAFF excess might contribute to the abnormal rescue of self-reactive B-cells at several checkpoints of the B-cell development and impair memory B-cell generation and functions. In this review, we first point out what is known about the functions of BAFF/a proliferation-inducing ligand and their receptors [B-cell maturation, transmembrane activator and CAML interactor (TACI), and BAFF-R], in physiological and pathophysiological settings, in mice and humans. In particular, we highlight recent results on the previously underappreciated regulatory functions of TACI and on the highly regulated production of soluble TACI and BAFF-R that act as decoy receptors. In light of recent data on BAFF, TACI, and BAFF-R, we then revisit the altered phenotypes and functions of B-cell subsets during the acute and chronic phase of HIV/SIV infection. Given the atypical phenotype and reduced functions of memory B-cells in HIV/SIV infection, we particularly discuss the GC reaction, a key checkpoint where self-reactive B-cells are eliminated and pathogen-specific memory B-cells and plasmablasts/cells are generated in physiological settings. Through its capacity to differentially bind and process BAFF-R and TACI on GC B-cells and possibly on follicular helper T-cells, BAFF appears as a key regulator of the physiological GC reaction. Its local excess during HIV/SIV infection could play a key role in B-cell dysregulations.