Key characteristics of anti-CD20 monoclonal antibodies and clinical implications for multiple sclerosis treatment

The recent success of anti-CD20 monoclonal antibody therapies in the treatment of multiple sclerosis (MS) has highlighted the role of B cells in the pathogenesis of MS. In people with MS, the inflammatory characteristics of B-cell activity are elevated, leading to increased pro-inflammatory cytokine release, diminished anti-inflammatory cytokine production and an accumulation of pathogenic B cells in the cerebrospinal fluid. Rituximab, ocrelizumab, ofatumumab, ublituximab and BCD-132 are anti-CD20 therapies that are either undergoing clinical development, or have been approved, for the treatment of MS. Despite CD20 being a common target for these therapies, differences have been reported in their mechanistic, pharmacological and clinical characteristics, which may have substantial clinical implications. This narrative review explores key characteristics of these therapies. By using clinical trial data and real-world evidence, we discuss their mechanisms of action, routes of administration, efficacy (in relation to B-cell kinetics), safety, tolerability and convenience of use. Clinicians, alongside patients and their families, should consider the aspects discussed in this review as part of shared decision-making discussions to improve outcomes and health-related quality of life for people living with MS.

Secondary hypogammaglobulinemia in patients with multiple sclerosis on anti-CD20 therapy: Pathogenesis, risk of infection, and disease management

Hypogammaglobulinemia is characterized by reduced serum immunoglobulin levels. Secondary hypogammaglobulinemia is of considerable interest to the practicing physician because it is a potential complication of some medications and may predispose patients to serious infections. Patients with multiple sclerosis (MS) treated with B-cell-depleting anti-CD20 therapies are particularly at risk of developing hypogammaglobulinemia. Among these patients, hypogammaglobulinemia has been associated with an increased risk of infections. The mechanism by which hypogammaglobulinemia arises with anti-CD20 therapies (ocrelizumab, ofatumumab, ublituximab, rituximab) remains unclear and does not appear to be simply due to the reduction in circulating B-cell levels. Further, despite the association between anti-CD20 therapies, hypogammaglobulinemia, and infections, there is currently no generally accepted monitoring and treatment approach among clinicians treating patients with MS. Here, we review the literature and discuss possible mechanisms of secondary hypogammaglobulinemia in patients with MS, hypogammaglobulinemia results in MS anti-CD20 therapy clinical trials, the risk of infection for patients with hypogammaglobulinemia, and possible strategies for disease management. We also include a suggested best-practice approach to specifically address secondary hypogammaglobulinemia in patients with MS treated with anti-CD20 therapies.

Ublituximab-xiiy as a treatment option for relapsing multiple sclerosis

INTRODUCTION

B cell depletion has been established as an efficacious anti-inflammatory therapy in people with relapsing forms of multiple sclerosis (MS). Ublituximab (ublituximab-xiiy) is the latest approved chimeric glycoengineered anti-CD20 monoclonal antibody (mAb) for the treatment of relapsing forms of MS.

AREAS COVERED

In this narrative review, the authors explore the safety and effectiveness of data derived from the Phase 2 and Phase 3 ublituximab trials and from their respective post-hoc analyses. Moreover, they consider the similarities and differences between the currently available anti-CD20 antibodies for treatment of relapsing MS. Lastly, the authors discuss the role and place of ublituximab in the current disease modifying therapy landscape.

EXPERT OPINION

Ublituximab is a rapid-acting and effective anti-inflammatory option as a treatment in people with relapsing MS that significantly reduced the annualized relapse rate and MRI-based disease activity. When compared to the Phase III trials of the other two anti-CD20 mAbs (ocrelizumab and ofatumumab), ublituximab did not result with reduction of 3 or 6-month confirmed disability progression. These differences may be attributed to the overall low rate of progression in both the ublituximab and the active comparator teriflunomide arm. Future data from open-label extensions are warranted. There was no significant reduction of ublituximab on whole-brain atrophy compared to teriflunomide.

Progressive multifocal leukoencephalopathy in anti-CD20 and other monoclonal antibody (mAb) therapies used in multiple sclerosis: A review

Progressive multifocal leukoencephalopathy (PML) is a subacute CNS inflammatory disease seen primarily among immunocompromised patients. It is caused by the JC virus (JCV), a polyomavirus that otherwise induces an insidious, latent infection in the general population. This reactivated disease is characterized by cognitive and behavioral changes, language disturbances, motor weakness, or visual deficits. Median survival in patients with AIDS is approximately 2-4 months, and mortality is high (around 4% in untreated AIDS). Recent scientific developments indicate that PML can also be associated with the increased utilization of monoclonal antibody (mAb) immunotherapy. In fact, PML has been witnessed with several mAbs, including natalizumab in multiple sclerosis, rituximab for lymphoma or lupus, efalizumab for psoriasis, and ofatumumab in leukemia; this leads us to the risk reassessment of PML due to treatment-induced immunosuppression. The range of clinical presentations of JCV-related disease has transformed over time and can pose significant challenges to the current diagnostic criteria. Most cases with PML suffer from persistent and irreversible neurological conditions, and some with chronic, low-level viral replication in the CNS. With the expanded use of mAbs for various autoimmune and lymphoproliferative disorders, we are now seeing this infection in non-HIV patients on drugs such as natalizumab, rituximab, and other recently approved therapies. This article aims to review the relationship between the incidence of PML and all four mAbs used in the treatment of MS. Currently, at least 18 FDA-approved medications carry label warnings for PML;to this date, no treatment has been convincingly effective.

Updates on efficacy and safety outcomes of new and emerging disease modifying therapies and stem cell therapy for Multiple Sclerosis: A review

Multiple Sclerosis (MS) is a chronic neurodegenerative autoimmune disorder of the central nervous system (CNS) and the most common cause of serious physical disability in working-age adults. Drug development and research in this field have rapidly evolved over the past two decades, leading to the broad array of treatment options available today. These disease-modifying therapies (DMTs) work through distinct mechanisms of action and exhibit varying safety and efficacy profiles to help manage symptoms and reduce exacerbations in MS patients. Our extensive understanding of this condition has also led to novel approaches, such as the discovery of specific biomarkers that allow us to monitor the therapeutic response towards DMTs. The development of new DMTs continues to progress quickly today, and it can be difficult for clinicians to remain up to date on the most recent advancements and new treatment options for their patients. In this comprehensive review, we provide an outline of current MS medications in the pipeline including emerging DMTs and stem cell therapy, as well as the unique characteristics of these medications, including their indications, pharmacokinetic effects, and the relevant advancements.

Monoclonal Antibodies in the Treatment of Relapsing Multiple Sclerosis: an Overview with Emphasis on Pregnancy, Vaccination, and Risk Management

Monoclonal antibodies have become a mainstay in the treatment of patients with relapsing multiple sclerosis (RMS) and provide some benefit to patients with primary progressive MS. They are highly precise by specifically targeting molecules displayed on cells involved in distinct immune mechanisms of MS pathophysiology. They not only differ in the target antigen they recognize but also by the mode of action that generates their therapeutic effect. Natalizumab, an [Formula: see text]4[Formula: see text]1 integrin antagonist, works via binding to cell surface receptors, blocking the interaction with their ligands and, in that way, preventing the migration of leukocytes across the blood-brain barrier. On the other hand, the anti-CD52 monoclonal antibody alemtuzumab and the anti-CD20 monoclonal antibodies rituximab, ocrelizumab, ofatumumab, and ublituximab work via eliminating selected pathogenic cell populations. However, potential adverse effects may be serious and can necessitate treatment discontinuation. Most importantly, those are the risk for (opportunistic) infections, but also secondary autoimmune diseases or malignancies. Monoclonal antibodies also carry the risk of infusion/injection-related reactions, primarily in early phases of treatment. By careful patient selection and monitoring during therapy, the occurrence of these potentially serious adverse effects can be minimized. Monoclonal antibodies are characterized by a relatively long pharmacologic half-life and pharmacodynamic effects, which provides advantages such as permitting infrequent dosing, but also creates disadvantages regarding vaccination and family planning. This review presents an overview of currently available monoclonal antibodies for the treatment of RMS, including their mechanism of action, efficacy and safety profile. Furthermore, we provide practical recommendations for risk management, vaccination, and family planning.

B cell depletion changes the immune cell profile in multiple sclerosis patients: One-year report

B cell depletion therapy has been shown to be beneficial in multiple sclerosis (MS). However, the mechanism by which B cell depletion mediates its beneficial effects in MS is still unclear. To better understand how B cell depletion may benefit patients with a disease previously thought to be primarily mediated by CD4 T cells, immune profiles were monitored in 48 patients in a phase II trial of ublituximab, a glycoengineered CD20 monoclonal antibody, at 18 time points over a year. As we previously described there was a significant shift in the percentages of T cells, NK cells, and myeloid cells following the initial dose of ublituximab, but this shift normalized within a week and these populations remained stable for the duration of the study. However, T cell subsets changed with an increase in the percentage of naïve CD4 and CD8 T cells and a decline in memory T cells. Importantly, the percentage of Th1 and CD4⁺GM-CSF⁺ T cells decreased, while the percentage of Tregs continued to increase over the year. Ublituximab not only depleted CD20⁺ B cells, but also CD20⁺ T cells. The favorable changes in the T cell subsets may contribute to the beneficial effects of B cell depletion therapy.

A Milestone in Multiple Sclerosis Therapy: Monoclonal Antibodies Against CD20-Yet Progress Continues

Multiple sclerosis (MS), which is a chronic inflammatory disease of the central nervous system, still represents one of the most common causes of persisting disability with an early disease onset. Growing evidence suggests B cells to play a crucial role in its pathogenesis and progression. Over the last decades, monoclonal antibodies (mabs) against the surface protein CD20 have been intensively studied as a B cell targeting therapy in relapsing MS (RMS) as well as primary progressive MS (PPMS). Pivotal studies on anti-CD20 therapy in RMS showed remarkable clinical and radiological effects, especially on acute inflammation and relapse biology. These results paved the way for further research on the implication of B cells in the pathogenesis of MS. Besides controlling relapse development in RMS, ocrelizumab (OCR) also showed clinical benefits in patients with PPMS and became the first approved drug for this disease course. In this review, we provide an overview of the current anti-CD20 mabs used or tested for the treatment of MS-namely rituximab (RTX), OCR, ofatumumab (OFA), and ublituximab (UB). Besides their effectiveness, we also discuss possible limitations and safety concerns especially in regard to long-term treatment, both for this class of drugs overall as well as for each anti-CD20 mab individually. Additionally, we elucidate to what extent anti-CD20 therapy may alter the function of other immune cells, both directly or indirectly. Finally, we cover the current knowledge on repopulation of CD20+ cells after cessation of anti-CD20 treatment and discuss future aspirations towards alternative, further developed B cell silencing therapies.

Comparison of the Efficacy and Safety of Anti-CD20 B Cells Depleting Drugs in Multiple Sclerosis

Rituximab, ocrelizumab, ofatumumab and ublituximab are disease modifying therapies (DMT) currently used in the treatment of multiple sclerosis (MS) or are in advanced stages of clinical trials. These monoclonal antibodies deplete B cells by targeting the cell surface protein CD20. This review highlights the similarities and major differences between the four agents. We summarize data from various clinical trials of each of these therapeutics and discuss their efficacy and safety. Additional considerations regarding the route of administration and cost are presented. Among the four therapeutics, only ocrelizumab is approved for primary progressive (PP) MS. Infusion/injection related reactions (IRRs) are the most common adverse events associated with all four therapeutics. In phase III trials of ocrelizumab and ofatumumab, the incidence of IRRs was lower with ofatumumab. Ofatumumab is unique among the four therapeutics due to its availability as a subcutaneous injection (SQ). Although SQ administration may be appealing for some patients it may raise concerns regarding medication compliance among physicians. Phase II trials studying ublituximab for the treatment of RMS yielded promising results. Phase III trials are currently comparing the efficacy of ublituximab to teriflunomide.

A phase 2 multicenter study of ublituximab, a novel glycoengineered anti-CD20 monoclonal antibody, in patients with relapsing forms of multiple sclerosis

Background:

Ublituximab, a novel monoclonal antibody (mAb) targeting a unique epitope on the CD20 antigen, is glycoengineered for enhanced B-cell targeting through antibody-dependent cellular cytotoxicity (ADCC). Greater ADCC may allow lower doses and shorter infusion times versus other anti-CD20 mAbs.

Objective:

The objective was to determine optimal dose, infusion time, and activity of ublituximab in relapsing multiple sclerosis.

Methods:

This is a phase 2, placebo-controlled study. Patients received three ublituximab infusions (150 mg over 1–4 hours on day 1 and 450–600 mg over 1–3 hours on day 15 and week 24) in six dosing cohorts. The primary endpoint was B-cell depletion.

Results:

In all cohorts (N = 48), median B-cell depletion was >99% by week 4, maintained at weeks 24 and 48. Most common adverse events (AEs) were infusion-related reactions (all grade 1–2), with no apparent increased incidence at shorter infusion times. There were no AE-related discontinuations. At weeks 24 and 48, no T1 gadolinium-enhancing lesions (p = 0.003) and a 10.6% decrease in T2 lesion volume (p = 0.002) were detected. The annualized relapse rate was 0.07; 93% remained relapse free on study. Overall, 74% of patients had no evidence of disease activity (NEDA).

Conclusion:

Ublituximab was safely infused as rapid as 1 hour, producing robust B-cell depletion and profound reductions in magnetic resonance imaging (MRI) activity and relapses.

Ublituximab for the treatment of CD20 positive B-cell malignancies

INTRODUCTION

Non-Hodgkin lymphoma (NHL) is the most common adult hematologic malignancy. Conventional methods of treatment are chemotherapy and radiation, which were associated with toxicities and lack of specificity. Potential cell surface targets for treatment of B-cell NHL (B-NHL) include CD19, CD20, and CD22 which are highly expressed on malignant B-cells. The development of monoclonal antibody (mAb) therapy directed against CD20 had the most clinical impact in the treatment of B-NHL. Early clinical trials with rituximab (RTX), the first chimeric mAb against CD20, showed efficacy and minimal toxicities. RTX was later approved as first line in combination with CHOP chemotherapy for Diffuse Large B-NHL (DLBCL). The emergence of resistance to RTX prompted the development of the next-generation of mAbs targeting CD20 (e.g. obinituzumab, ofatumumab), and includes ublituximab (Ub), with higher complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) against malignant B-cells. Areas covered: Herein, we discuss clinical trials of Ub, highlighting efficacy, tolerability and an expert opinion on drug development in B-NHL. A pubmed search was conducted to evaluate all Ub clinical trials. Expert opinion: Ub demonstrated efficacy in patients with high-risk CLL and B-NHL in both first line, subsequent lines, and in rituximab refractory patients.

Dancing partners at the ball: Rational selection of next generation anti-CD20 antibodies for combination therapy of chronic lymphocytic leukemia in the novel agents era

The anti-CD20 antibodies represent a major advancement in the therapeutic options available for chronic lymphocytic leukemia. The addition of rituximab, ofatumumab and obinutuzumab to various chemotherapy regimens has led to considerable improvements in both response and survival. Ocaratuzumab, veltuzumab and ublituximab are currently being explored within the trial setting. We review the current status of these antibodies, and discuss how their mechanisms of action may impact on the choice of combinations with novel small molecule agents.

Possible novel agents in marginal zone lymphoma

Efficacy, safety and mechanisms of action of novel agents in marginal zone lymphoma patients, both with a nodal and extranodal presentation, are reviewed. Data on lenalidomide, bortezomib and ⁹⁰yttrium-ibrutumomab tiuxetan are obtained from trials specifically designed for patients affected by marginal zone lymphoma and with various disease presentations. The role of targeted agents, such as obinutuzumab, ibrutinib and idelalisib, and of some very new drugs (venetoclax, copanlisib, ublituximab and TGR-1202) is also discussed, taking into account the most relevant experiences in patients with indolent non-Hodgkin's lymphomas. A glance to some possible drug combinations will also be provided, along with an update of the most relevant ongoing trials.