Rapid Progress in Immunotherapies for Multiple Myeloma: An Updated Comprehensive Review

Prognostic value of the Controlling Nutritional Status score in patients with newly diagnosed multiple myeloma

OBJECTIVE

There is some evidence indicating that the Controlling Nutritional Status (CONUT) score is a prognostic factor in patients with hematological malignancies, including multiple myeloma (MM). The aim of this study was to assess the prognostic value of the CONUT score in newly diagnosed MM.

METHOD

We retrospectively investigated multiple clinical variables, including the CONUT score, age, sex, body mass index, M protein type, International Staging System (ISS) stage, Durie-Salmon (DS) stage, and blood cell count, in 58 patients with newly diagnosed MM.

RESULT

There was a significant correlation between a high CONUT score (>5.5) and poor OS. The prognostic impact of this score was more significant in patients with a low ISS or DS stage. In univariate analysis, the white blood cell count (P=0.021), monocyte count (P=0.022), eosinophil count (P=0.004), and lactic dehydrogenase (LDH) (P=0.042) predicted OS. Multivariate analysis identified the CONUT score (P=0.012), monocyte count (P=0.008), eosinophil count (P=0.031), and LDH (P=0.001) to be independent prognostic factors for overall survival (OS).

CONCLUSION

The CONUT score is a useful prognostic indicator in patients with MM, especially those with a low ISS or DS stage. The monocyte count, eosinophil count, and LDH are independent prognostic factors in these patients.

Ribosomal protein S3 mediates drug resistance of proteasome inhibitor: potential therapeutic application in multiple myeloma

Multiple myeloma (MM) remains incurable due to drug resistance. Ribosomal protein S3 (RPS3) has been identified as a non-Rel subunit of NF-κB. However, the detailed biological roles of RPS3 remain unclear. Here, we report for the first time that RPS3 is necessary for MM survival and drug resistance. RPS3 was highly expressed in MM, and knockout of RPS3 in MM inhibited cell growth and induced cell apoptosis both in vitro and in vivo. Overexpression of RPS3 mediated the proteasome inhibitor resistance of MM and shortened the survival of MM tumor-bearing animals. Moreover, our present study found an interaction between RPS3 and the thyroid hormone receptor interactor 13 (TRIP13), an oncogene related to MM tumorigenesis and drug resistance. We demonstrated that the phosphorylation of RPS3 was mediated by TRIP13 via PKCδ, which played an important role in activating the canonical NF-κB signaling and inducing cell survival and drug resistance in MM. Notably, the inhibition of NF-κB signaling by the small-molecule inhibitor targeting TRIP13, DCZ0415, was capable of triggering synergistic cytotoxicity when combined with bortezomib in drug-resistant MM. This study identifies RPS3 as a novel biomarker and therapeutic target in MM.

Trends in risk for therapy-related myelodysplastic syndrome/acute myeloid leukemia after initial chemo/immunotherapy for common and rare lymphoid neoplasms, 2000-2018

Background

Historically, survivors of common lymphoid neoplasms (LNs) had increased risks for therapy-related myelodysplastic syndrome/acute myeloid leukemia (tMDS/AML). Despite major treatment advances in the treatment of LNs over the last two decades, a comprehensive evaluation of tMDS/AML trends following both common and rare LNs treated in this contemporary period is lacking.

Methods

In US cancer registries during 2000-2018, we identified 1496 tMDS/AML cases among 186,503 adults who were treated with initial chemo/immunotherapy for first primary LN and survived ≥1 year. We quantified tMDS/AML standardized incidence ratios (SIRs), excess absolute risks (EARs, per 10,000 person-years), and cumulative incidence.

Findings

The highest tMDS/AML risks occurred after precursor leukemia/lymphoma (SIR = 39, EAR = 30), Burkitt leukemia/lymphoma (SIR = 20, EAR = 24), peripheral T-cell lymphoma (SIR = 12, EAR = 23), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL; SIR = 9.0, EAR = 27), and mantle cell lymphoma (SIR = 8.5, EAR = 25). Elevated risks (SIRs = 4.2-6.9, EARs = 4.9-15) also were observed after all other LN subtypes except hairy cell leukemia and mycosis fungoides/Sézary syndrome. Among patients treated more recently, tMDS/AML risks were significantly higher after CLL/SLL (SIR_2000-2005 = 4.8, SIR_2012-2017 = 10, P_trend = 0.0043), significantly lower after Hodgkin (SIR_2000-2005 = 15, SIR_2012-2017 = 6.3, P_trend = 0.024) and marginal zone (SIR_2000-2005 = 7.5, SIR_2012-2017 = 2.3, P_trend = 0.015) lymphomas, and non-significantly lower after mantle cell lymphoma (SIR_2000-2005 = 10, SIR_2012-2017 = 3.2, P_trend = 0.054), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (SIR_2000-2005 = 6.9, SIR_2012-2017 = 1.0, P_trend = 0.067), and plasma cell neoplasms (SIR_2000-2005 = 5.4, SIR_2012-2017 = 3.1, P_trend = 0.051). EAR and cumulative incidence trends generally were similar to SIR trends. Median survival after tMDS/AML was 8.0 months (interquartile range, 3.0-22.0).

Interpretation

Although tMDS/AML risks are significantly elevated after initial chemo/immunotherapy for most LNs, patients treated more recently have lower tMDS/AML risks, except after CLL/SLL. Though rare, the poor prognosis following tMDS/AML emphasizes the importance of continued efforts to reduce treatment-associated toxicity.

Funding

This research was supported in part by the Intramural Research Program of the National Cancer Institute, National Institutes of Health. LMM, GMD, REC, and CBS verified the data, and all authors had access to the data and made the decision to submit for publication.

The Effect of Belantamab Mafodotin on Primary Myeloma–Stroma Co-Cultures: Asymmetrical Mitochondrial Transfer between Myeloma Cells and Autologous Bone Marrow Stromal Cells

Belantamab mafodotin (belamaf) is an afucosylated monoclonal antibody conjugated to the microtubule disrupter monomethyl auristatin-F (MMAF) that targets B cell maturation antigen (BCMA) on the surface of malignant plasma cells. Belamaf can eliminate myeloma cells (MMs) through several mechanisms. On the one hand, in addition to inhibiting BCMA-receptor signaling and cell survival, intracellularly released MMAF disrupts tubulin polymerization and causes cell cycle arrest. On the other hand, belamaf induces effector cell-mediated tumor cell lysis via antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis. In our in vitro co-culture model, the consequences of the first mentioned mechanism can be investigated: belamaf binds to BCMA, reduces the proliferation and survival of MMs, and then enters the lysosomes of malignant cells, where MMAF is released. The MMAF payload causes a cell cycle arrest at the DNA damage checkpoint between the G2 and M phases, resulting in caspase-3-dependent apoptosis. Here, we show that primary MMs isolated from different patients can vary widely in terms of BCMA expression level, and inadequate expression is associated with extremely high resistance to belamaf according to our cytotoxicity assay. We also reveal that primary MMs respond to increasing concentrations of belamaf by enhancing the incorporation of mitochondria from autologous bone marrow stromal cells (BM-MSCs), and as a consequence, MMs become more resistant to belamaf in this way, which is similar to other medications we have analyzed previously in this regard, such as proteasome inhibitor carfilzomib or the BCL-2 inhibitor venetoclax. The remarkable resistance against belamaf observed in the case of certain primary myeloma cell cultures is a cause for concern and points towards the use of combination therapies to overcome the risk of antigen escape.

Clinical Management of Triple-Class Refractory Multiple Myeloma: A Review of Current Strategies and Emerging Therapies

Major progress has been made in the upfront treatment of multiple myeloma, but the disease ultimately relapses and leads to death in the vast majority of those afflicted. New treatment strategies and modalities are necessary to treat myeloma in relapse, particularly in cases of triple-refractory status defined by disease progression during or shortly after treatment with immunomodulatory agents, proteasome inhibitors, and anti-CD38 monoclonal antibody therapy. In this manuscript, we review recent promising developments in the treatment of triple-class refractory myeloma including bispecific antibodies and T cell engagers, chimeric antigen receptor cellular therapies, as well as chemotherapeutics with novel mechanisms of action.

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

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

Secondary Immunodeficiency in Hematological Malignancies: Focus on Multiple Myeloma and Chronic Lymphocytic Leukemia

Secondary immunodeficiency is reported in most patients with hematological malignancies such as chronic lymphocytic leukemia and multiple myeloma. The aim of our review was to evaluate the existing literature data on patients with hematological malignancies, with regard to the effect of immunodeficiency on the outcome, the clinical and therapeutic approach, and on the onset of noninfectious complications, including thrombosis, pleural effusion, and orofacial complications. Immunodeficiency in these patients has an intense impact on their risk of infection, in turn increasing morbidity and mortality even years after treatment completion. However, these patients with increased risk of severe infectious diseases could be treated with adequate vaccination coverage, but the vaccines' administration can be associated with a decreased immune response and an augmented risk of adverse reactions. Probably, immunogenicity of the inactivated is analogous to that of healthy subjects at the moment of vaccination, but it undertakes a gradual weakening over time. However, the dispensation of live attenuated viral vaccines is controversial because of the risk of the activation of vaccine viruses. A particular immunization schedule should be employed according to the clinical and immunological condition of each of these patients to guarantee a constant immune response without any risks to the patients' health.

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.