Evaluation of the QTc prolongation potential of a monoclonal antibody, siltuximab, in patients with monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, or low-volume multiple myeloma

The diverse landscape of dermatologic toxicities of non-immune checkpoint inhibitor monoclonal antibody-based cancer therapy

BACKGROUND

Since their first approval 25 years ago, monoclonal antibodies (mAbs) have become important targeted cancer therapeutics. However, dermatologic toxicities associated with non-immune checkpoint inhibitor (non-ICI) mAbs may complicate the course of cancer treatment. Data on the incidence and types of these reactions are limited.

METHODS

A comprehensive review was conducted on dermatologic toxicities associated with different classes of non-ICI mAbs approved for treatment of solid tumors and hematologic malignancies. The review included prospective Phase 1, 2, and 3 clinical trials; retrospective literature reviews; systematic reviews/meta-analyses; and case series/reports.

RESULTS

Dermatologic toxicities were associated with several types of non-ICI mAbs. Inflammatory reactions were the most common dermatologic toxicities, manifesting as maculopapular, urticarial, papulopustular/acneiform, and lichenoid/interface cutaneous adverse events (cAEs) with non-ICI mAbs. Immunobullous reactions were rare and a subset of non-ICI mAbs were associated with the development of vitiligo cAEs.

CONCLUSION

Dermatologic toxicities of non-ICI mAbs are diverse and mostly limited to inflammatory reactions. Awareness of the spectrum of the histopathologic patterns of cAE from non-ICI mAbs therapy is critical in the era of oncodermatology and oncodermatopathology.

Inflammatory and Anti-Inflammatory Equilibrium, Proliferative and Antiproliferative Balance: The Role of Cytokines in Multiple Myeloma

Multiple myeloma (MM) is typically exemplified by a desynchronized cytokine system with increased levels of inflammatory cytokines. We focused on the contrast between inflammatory and anti-inflammatory systems by assessing the role of cytokines and their influence on MM. The aim of this review is to summarize the available information to date concerning this equilibrium to provide an overview of the research exploring the roles of serum cytokines in MM. However, the association between MM and inflammatory cytokines appears to be inadequate, and other functions, such as pro-proliferative or antiproliferative effects, can assume the role of cytokines in the genesis and progression of MM. It is possible that inflammation, when guided by cancer-specific Th1 cells, may inhibit tumour onset and progression. In a Th1 microenvironment, proinflammatory cytokines (e.g., IL-6 and IL-1) may contribute to tumour eradication by attracting leucocytes from the circulation and by increasing CD4 ⁺ T cell activity. Hence, caution should be used when considering therapies that target factors with pro- or anti-inflammatory activity. Drugs that may reduce the tumour-suppressive Th1-driven inflammatory immune response should be avoided. A better understanding of the relationship between inflammation and myeloma will ensure more effective therapeutic interventions.

Interleukin-6/STAT3 signaling as a promising target to improve the efficacy of cancer immunotherapy

Overcoming the immunosuppressive state in tumor microenvironments is a critical issue for improving the efficacy of cancer immunotherapy. Interleukin (IL)‐6, a pleiotropic cytokine, is highly produced in the tumor‐bearing host. Previous studies have indicated that IL‐6 suppresses the antigen presentation ability of dendritic cells (DC) through activation of signal transducer and activator of transcription 3 (STAT3). Thus, we focused on the precise effect of the IL‐6/STAT3 signaling cascade on human DC and the subsequent induction of antitumor T cell immune responses. Tumor‐infiltrating CD11b⁺CD11c⁺ cells isolated from colorectal cancer tissues showed strong induction of the IL‐6 gene, downregulated surface expression of human leukocyte antigen (HLA)‐DR, and an attenuated T cell‐stimulating ability compared with those from peripheral blood mononuclear cells, suggesting that the tumor microenvironment suppresses antitumor effector cells. In vitro experiments revealed that IL‐6‐mediated STAT3 activation reduced surface expression of HLA‐DR on CD14⁺ monocyte‐derived DC. Moreover, we confirmed that cyclooxygenase 2, lysosome protease and arginase activities were involved in the IL‐6‐mediated downregulation of the surface expression levels of HLA class II on human DC. These findings suggest that IL‐6‐mediated STAT3 activation in the tumor microenvironment inhibits functional maturation of DC to activate effector T cells, blocking introduction of antitumor immunity in cancers. Therefore, we propose in this review that blockade of the IL‐6/STAT3 signaling pathway and target molecules in DC may be a promising strategy to improve the efficacy of immunotherapies for cancer patients.

Siltuximab and hematologic malignancies. A focus in non Hodgkin lymphoma

INTRODUCTION

The role of interleukin-6 (IL-6) in tumorigenesis and in particular in haematological malignancies is crucial. On the basis of the favourable results obtained in the subset of multicentric Castleman disease (MCD), Siltuximab, a chimeric, human-murine, immunoglobulin (Ig) Gk monoclonal antibody directed against human IL-6 has been evaluated in haematological malignancies such as multiple myeloma, myelodisplastic syndromes and non Hodgkin lymphomas. Areas covered: This review discusses available data related to the role of IL-6 as a therapeutic target, the characteristics of Siltuximab in term pharmacokinetics and pharmacodynamics properties and a detailed analysis of the studies involving haematological malignancies with a peculiar focus on non Hodgkin lymphoma. Expert opinion: The results obtained with Siltuximab in haematological malignancies and in particular with non Hodgkin lymphoma are inferior to those obtained in MCD. The complex interaction between malignant clones, inflammatory background and host response could justify this difference. New interesting areas of study are the role of Siltuximab in early phase of multiple myeloma (smoldering multiple myeloma) and if there may be a possible future application in the treatment of Waldenström macroglobulinemia.

Biologics for Targeting Inflammatory Cytokines, Clinical Uses, and Limitations

Proinflammatory cytokines are potent mediators of numerous biological processes and are tightly regulated in the body. Chronic uncontrolled levels of such cytokines can initiate and derive many pathologies, including incidences of autoimmunity and cancer. Therefore, therapies that regulate the activity of inflammatory cytokines, either by supplementation of anti-inflammatory recombinant cytokines or by neutralizing them by using blocking antibodies, have been extensively used over the past decades. Over the past few years, new innovative biological agents for blocking and regulating cytokine activities have emerged. Here, we review some of the most recent approaches of cytokine targeting, focusing on anti-TNF antibodies or recombinant TNF decoy receptor, recombinant IL-1 receptor antagonist (IL-1Ra) and anti-IL-1 antibodies, anti-IL-6 receptor antibodies, and TH17 targeting antibodies. We discuss their effects as biologic drugs, as evaluated in numerous clinical trials, and highlight their therapeutic potential as well as emphasize their inherent limitations and clinical risks. We suggest that while systemic blocking of proinflammatory cytokines using biological agents can ameliorate disease pathogenesis and progression, it may also abrogate the hosts defense against infections. Moreover, we outline the rational need to develop new therapies, which block inflammatory cytokines only at sites of inflammation, while enabling their function systemically.

Siltuximab: A Review in Idiopathic (Human Herpesvirus-8-Negative) Multicentric Castleman Disease

Siltuximab (Sylvant™), an interleukin (IL)-6 chimeric immunoglobulin Gк monoclonal antibody, is a currently the only agent approved to treat human idiopathic (herpesvirus-8 negative) multicentric Castleman disease (iMCD), which is a rare lymphoproliferative disorder. iMCD is caused by dysregulated production of IL-6 in the lymph nodes, and is associated with high morbidity, and potentially fatal consequences. Siltuximab binds to human IL-6 with high affinity and specificity, thereby preventing it from binding to IL-6 receptors, and neutralizing IL-6 bioactivity. In clinical trials in patients with iMCD, siltuximab reduced levels of C-reactive protein (a biomarker for IL-6), and provided clinical responses. Relative to placebo, the addition of siltuximab to best supportive care improved tumor- and symptom-related outcomes, with patients also reporting improvements in MCD symptoms, functional status, and well-being. Siltuximab has an acceptable tolerability profile, with the majority of treatment-emergent adverse events being manageable and/or of mild severity. In the absence of a cure, siltuximab represents a significant achievement in the management of this difficult-to-treat orphan disease.

Monoclonal antibodies in the treatment of multiple myeloma: current status and future perspectives

The treatment landscape for patients with multiple myeloma (MM) is constantly evolving. Over the past decade, the introduction of novel agents such as proteasome inhibitors and immunomodulatory drugs has led to notable changes in therapeutic strategy, and improvements in survival, yet MM remains incurable in the vast majority of cases. More recently, a targeted approach to MM treatment has emerged, using monoclonal antibodies (mAbs) to target antigens expressed on the surface of MM cells. MAbs tested to date kill MM cells via the host's immune system and/or by promoting apoptosis, and appear to have generally improved tolerability compared with currently available treatments. Due to their distinct mode of action, mAbs are promising both for patients who have exhausted current regimens, and as part of first-line treatments in newly diagnosed patients. This review examines the recent developments in mAb-based therapy for MM, primarily focused on those agents in ongoing clinical testing.

Siltuximab (CNTO 328): a promising option for human malignancies

Siltuximab (CNTO 328) is a promising antibody-drug conjugate targeting cytokine interleukin-6 (IL-6). It is highly binding to IL-6 and thus neutralizing IL-6 bioactivity and promoting death of tumor cell. In this review, we mainly focus on the mechanisms, clinical studies, and adverse effect of siltuximab in the treatment of human malignancies. We also provide our recommendations for siltuximab treatment in the future.

Siltuximab for multicentric Castleman disease

Dysregulated secretion of IL-6 plays a pivotal role in the pathogenesis of Castleman disease (CD), a rare lymphoproliferative disorder. In contrast to unicentric CD for which surgery is considered the treatment of choice, there is no standard therapeutic approach for multicentric CD (MCD). Siltuximab (trade name: Sylvant, formerly known as CNTO 328) is a chimeric monoclonal antibody with high binding affinity for human IL-6. In a recent randomized placebo-controlled Phase II trial, subjects with HIV-negative, HHV8-negative MCD who received siltuximab demonstrated a significantly higher rate of durable tumor and symptomatic response with a tolerable safety profile, leading to its approval for the treatment of HIV-negative HHV8-negative MCD by the US FDA and the European Commission in April and May 2014, respectively. This article will cover the current treatment options of MCD, the drug profile of siltuximab and future directions in the management of MCD.