Monoclonal antibodies in the treatment of multiple sclerosis: emergence of B-cell-targeted therapies

The next frontier in multiple sclerosis therapies: Current advances and evolving targets

Recent advancements in research have significantly enhanced our comprehension of the intricate immune components that contribute to multiple sclerosis (MS) pathogenesis. By conducting an in-depth analysis of complex molecular interactions involved in the immunological cascade of the disease, researchers have successfully identified novel therapeutic targets, leading to the development of innovative therapies. Leveraging pioneering technologies in proteomics, genomics, and the assessment of environmental factors has expedited our understanding of the vulnerability and impact of these factors on the progression of MS. Furthermore, these advances have facilitated the detection of significant biomarkers for evaluating disease activity. By integrating these findings, researchers can design novel molecules to identify new targets, paving the way for improved treatments and enhanced patient care. Our review presents recent discoveries regarding the pathogenesis of MS, highlights their genetic implications, and proposes an insightful approach for engaging with newer therapeutic targets in effectively managing this debilitating condition.

A new perspective on therapies involving B-cell depletion in autoimmune diseases

It has been rediscovered in the last fifteen years that B-cells play an active role in autoimmune etiology rather than just being spectators. The clinical success of B-cell depletion therapies (BCDTs) has contributed to this. BCDTs, including those that target CD20, CD19, and BAFF, were first developed to eradicate malignant B-cells. These days, they treat autoimmune conditions like multiple sclerosis and systemic lupus erythematosus. Particular surprises have resulted from the use of BCDTs in autoimmune diseases. For example, even in cases where BCDT is used to treat the condition, its effects on antibody-secreting plasma cells and antibody levels are restricted, even though these cells are regarded to play a detrimental pathogenic role in autoimmune diseases. In this Review, we provide an update on our knowledge of the biology of B-cells, examine the outcomes of clinical studies employing BCDT for autoimmune reasons, talk about potential explanations for the drug's mode of action, and make predictions about future approaches to targeting B-cells other than depletion.

Quantitative comparison of the efficacy of clinical drug treatments for primary progressive multiple sclerosis

OBJECTIVE

This study proposes a comprehensive quantitative evaluation of the efficacy of drugs and placebo in clinical trials for primary progressive multiple sclerosis (PPMS).

METHODS

A literature search was conducted using the PubMed, EMBASE, and Cochrane library databases and the clinical studies reporting drug efficacy in the treatment of PPMS were included in the analyses. The cumulative proportion of patients without confirmed disability progression (wCDP%) was used as the main efficacy endpoint. The model-based meta-analysis method was used to describe the time course of each drug (as well as placebo) in order to rank the drug efficacy for the treatment of PPMS.

RESULTS

Fifteen studies involving 3779 patients were included, of which, nine were placebo-controlled and six were single-arm trials. Twelve drugs were included in the study. The results showed that, except for biotin, interferon β-1a, and interferon β-1b, whose efficacy was comparable to the placebo, the efficacy of the other 9 drugs were significantly better than placebo. Among these, ocrelizumab showed outstanding performance, with wCDP% of 72.6 at 96 weeks, while the proportions of rest of the drugs ranged between approximately 55-70%.

CONCLUSION

The results of this study provide the necessary quantitative information for both the rational clinical use of drugs and future clinical trials in primary progressive multiple sclerosis.

The Efficacy and Safety of Anti-CD20 Antibody Treatments in Relapsing Multiple Sclerosis: A Systematic Review and Network Meta-analysis

BACKGROUND

Several large randomized controlled trials of anti-CD20 antibodies have been successfully conducted for the treatment of relapsing multiple sclerosis. Despite this, there are few systematic comparisons of different anti-CD20 antibodies and a comprehensive evaluation of their efficacy and safety is yet to be carried out.

OBJECTIVE

The objective of this systematic review and network meta-analysis was to evaluate the efficacy and safety of the three approved anti-CD20 antibodies for the treatment of relapsing multiple sclerosis and to aid clinicians in choosing medications.

METHODS

MEDLINE, EMBASE, Cochrane Library, and clinicaltrials.gov were all searched for randomized controlled trials conducted to evaluate anti-CD20 antibodies (rituximab, ocrelizumab, ofatumumab) and corresponding controls up to 31 May, 2022. Review Manager 5.3 and R 3.5.2 software were used to assess the data. The risk ratio and mean difference were analyzed and calculated with a random-effects model.

RESULTS

We pooled 4181 patients from ten randomized controlled trials. Without increasing the risk of adverse events and serious adverse events, anti-CD20 antibodies were superior to the active control group in all efficacy outcomes (both p < 0.005, certainty of evidence, very low to high). For the comparison between anti-CD20 groups, rituximab was found to be able to significantly increase the number of patients free of relapse more effectively than the other two interventions; however, the surface under curve ranking area values for serious adverse events were also the highest (84.8%). At the same time, ocrelizumab and ofatumumab exhibited satisfactory efficacy without showing a worse safety than any other interventions.

CONCLUSIONS

Overall, anti-CD20 antibody treatment is superior to a corresponding control in efficacy and safety measures and ocrelizumab and ofatumumab may be the most suitable anti-CD20 antibodies for treating relapsing multiple sclerosis. Additional large-scale and high-quality studies are still needed to further explore the safety of these therapies.

Autoantibodies - enemies, and/or potential allies?

Autoantibodies are well known as potentially highly harmful antibodies which attack the host via binding to self-antigens, thus causing severe associated diseases and symptoms (e.g. autoimmune diseases). However, detection of autoantibodies to a range of disease-associated antigens has enabled their successful usage as important tools in disease diagnosis, prognosis and treatment. There are several advantages of using such autoantibodies. These include the capacity to measure their presence very early in disease development, their stability, which is often much better than their related antigen, and the capacity to use an array of such autoantibodies for enhanced diagnostics and to better predict prognosis. They may also possess capacity for utilization in therapy, in vivo. In this review both the positive and negative aspects of autoantibodies are critically assessed, including their role in autoimmune diseases, cancers and the global pandemic caused by COVID-19. Important issues related to their detection are also highlighted.

Memory B Cells in Multiple Sclerosis: Emerging Players in Disease Pathogenesis

Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Once thought to be primarily driven by T cells, B cells are emerging as central players in MS immunopathogenesis. Interest in multiple B cell phenotypes in MS expanded following the efficacy of B cell-depleting agents targeting CD20 in relapsing-remitting MS and inflammatory primary progressive MS patients. Interestingly, these therapies primarily target non-antibody secreting cells. Emerging studies seek to explore B cell functions beyond antibody-mediated roles, including cytokine production, antigen presentation, and ectopic follicle-like aggregate formation. Importantly, memory B cells (Bmem) are rising as a key B cell phenotype to investigate in MS due to their antigen-experience, increased lifespan, and rapid response to stimulation. Bmem display diverse effector functions including cytokine production, antigen presentation, and serving as antigen-experienced precursors to antibody-secreting cells. In this review, we explore the cellular and molecular processes involved in Bmem development, Bmem phenotypes, and effector functions. We then examine how these concepts may be applied to the potential role(s) of Bmem in MS pathogenesis. We investigate Bmem both within the periphery and inside the CNS compartment, focusing on Bmem phenotypes and proposed functions in MS and its animal models. Finally, we review how current immunomodulatory therapies, including B cell-directed therapies and other immunomodulatory therapies, modify Bmem and how this knowledge may be harnessed to direct therapeutic strategies in MS.

Early Aggressive Treatment Approaches for Multiple Sclerosis

PURPOSE OF REVIEW

This review presents a comprehensive analysis of the current high-efficacy disease-modifying therapies (DMTs) available for treatment of multiple sclerosis (MS). We discuss the existing approved and emerging therapeutics in patients with relapsing and progressive forms of MS using data from clinical trials and observational studies. Treatment considerations in pediatric and pregnant populations are also reviewed. Finally, we discuss the treatment paradigms of the escalation and early aggressive approaches to treatment of MS, with review of ongoing clinical trials to compare these approaches.

RECENT FINDINGS

Natalizumab has shown promising data on efficacy in not only randomized trials but also observational studies when compared with placebo, the injectable DMTs, and fingolimod. The anti-CD20 B cell depleting therapies (rituximab, ocrelizumab, and ofatumumab) have also demonstrated superiority in randomized clinical trials compared to their comparator group (placebo, interferon, and teriflunomide, respectively) and rituximab has shown in observational studies to be more effective than older injectable therapies and some of the oral therapies. Alemtuzumab has shown good efficacy in randomized controlled trials and observational studies yet has several potentially severe side effects limiting its use. Mitoxantrone has similarly demonstrated significant reduction in new disease activity compared to placebo but is rarely used due to its severe side effects. Cladribine is an oral DMT often grouped in discussion with other higher efficacy DMTs but may be slightly less effective than the other therapies described in this review. Many emerging targets for therapeutic intervention are currently under investigation that may prove to be beneficial in early aggressive MS, including autologous hematopoietic stem cell transplantation.

SUMMARY

Traditionally, MS has been treated with an escalation approach, starting patients on a modestly effective DMT and subsequently escalating to a higher efficacy DMT when there is evidence of clinical and/or radiologic breakthrough activity. With the development of higher efficacy therapies and emerging data showing the potential positive long-term impact of these therapies when started earlier in the disease course, many clinicians have shifted to an early aggressive treatment approach in which patients are initially started on a higher efficacy DMT. Two clinical trials, the TRaditional versus Early Aggressive Therapy for MS (TREAT-MS) trial and the Determining the Effectiveness of earLy Intensive Versus Escalation approaches for the treatment of Relapsing-remitting MS (DELIVER-MS) trial, aim to directly compare these treatment strategies and their impact on clinical and radiologic outcomes.

Decoding intrathecal immunoglobulins and B cells in the CNS: their synthesis, function, and regulation

The discovery of an active lymphatic system in the meninges (dura mater) has opened up a wide range of possibilities for the role of CNS immunoglobulins in brain development in early fetal life or during infancy. The antibody-dependent and -independent functions of B cells in the immunopathogenesis of multiple sclerosis are not new to immunologists, yet their role in other neurodegenerative disorders such as Alzheimer's and Parkinson's disease is incompletely understood. Deep cervical lymph nodes have emerged as a candidate site for autosensitization against CNS antigens and have been shown to provide the right kind of milieu for the dynamic interaction of antigen-presenting cells, B cells, and T cells. The presence of different B cells in the lymph nodes and the production of natural autoantibodies by B-1 cells have definitely unlocked another piece of the puzzle. At a time when CD19 and CD20 monoclonal antibodies have shown remarkable results in ameliorating the relapse and progression of multiple sclerosis, it is imperative to dissect out the diversity in B cell populations inside the CNS to identify new targets to improve current treatment regimens for neurodegenerative diseases. This review highlights the origin, migration, function, and regulation of B cells and the production of intrathecal immunoglobulins considering the previous and current findings and taking into account the differences between a healthy state and the changes that occur during an inflammatory or autoimmune response.

Inflammatory Role of TLR-MyD88 Signaling in Multiple Sclerosis

Multiple sclerosis (MS) is a neuro-autoimmune and neurodegenerative disorder leading to chronic inflammation, demyelination, axonal, and neuronal loss in the central nervous system (CNS). Despite intense research efforts, the pathogenesis of MS still remains unclear. Toll-like receptors (TLRs) are a family of type I transmembrane receptors that play a crucial role in the innate immune response. Myeloid differentiation factor 88 (MyD88) is the adaptor of major TLRs. It has been widely considered that the TLR-MyD88 signaling pathway plays an important role in the occurrence and development of autoimmune disease. Data have revealed that the TLR-MyD88 signaling may be involved in the pathogenesis of MS and experimental autoimmune encephalomyelitis (EAE), an animal model for MS, by regulating the antigen presentation of dendritic cells, the integrity of blood-brain barrier (BBB), and the activation of T cells and B cells. Here, we summarize the role of TLRs and MyD88 in MS and discuss the possible therapies that are based on these molecules.

Biological characteristics of transcription factor RelB in different immune cell types: implications for the treatment of multiple sclerosis

Transcription factor RelB is a member of the nuclear factror-kappa B (NF-κB) family, which plays a crucial role in mediating immune responses. Plenty of studies have demonstrated that RelB actively contributes to lymphoid organ development, dendritic cells maturation and function and T cells differentiation, as well as B cell development and survival. RelB deficiency may cause a variety of immunological disorders in both mice and humans. Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system which involves a board of immune cell populations. Thereby, RelB may exert an impact on MS by modulating the functions of dendritic cells and the differentiation of T cells and B cells. Despite intensive research, the role of RelB in MS and its animal model, experimental autoimmune encephalomyelitis, is still unclear. Herein, we give an overview of the biological characters of RelB, summarize the updated knowledge regarding the role of RelB in different cell types that contribute to MS pathogenesis and discuss the potential RelB-targeted therapeutic implications for MS.

Minimal breast milk transfer of rituximab, a monoclonal antibody used in neurological conditions

Objective

To determine the transfer of rituximab, an anti-CD20 monoclonal antibody widely used for neurologic conditions, into mature breast milk.

Methods

Breast milk samples were collected from 9 women with MS who received rituximab 500 or 1,000 mg intravenous once or twice while breastfeeding from November 2017 to April 2019. Serial breast milk samples were collected before infusion and at 8 hours, 24 hours, 7 days, and 18–21 days after rituximab infusion in 4 patients. Five additional patients provided 1–2 samples at various times after rituximab infusion.

Results

The median average rituximab concentration in mature breast milk was low at 0.063 μg/mL (range 0.046–0.097) in the 4 patients with serial breast milk collection, with an estimated median absolute infant dose of 0.0094 mg/kg/d and a relative infant dose (RID) of 0.08% (range 0.06%–0.10%). Most patients had a maximum concentration at 1–7 days after infusion. The maximum concentration occurred in a woman with a single breast milk sample and was 0.29 μg/mL at 11 days postinfusion, which corresponds with an estimated RID of 0.33%. Rituximab concentration in milk was virtually undetectable by 90 days postinfusion.

Conclusions

We determined minimal transfer of rituximab into mature breast milk. The RID for rituximab was less than 0.4% and well below theoretically acceptable levels of less than 10%. Low oral bioavailability would probably also limit the absorption of rituximab by the newborn. In women with serious autoimmune neurologic conditions, monoclonal antibody therapy may afford an acceptable benefit to risk ratio, supporting both maternal treatment and breastfeeding.

Potential role of CSF cytokine profiles in discriminating infectious from non-infectious CNS disorders

Current laboratory testing of cerebrospinal fluid (CSF) does not consistently discriminate between different central nervous system (CNS) disease states. Rapidly distinguishing CNS infections from other brain and spinal cord disorders that share a similar clinical presentation is critical. New approaches focusing on aspects of disease biology, such as immune response profiles that can have stimulus-specific attributes, may be helpful. We undertook this preliminary proof-of-concept study using multiplex ELISA to measure CSF cytokine levels in various CNS disorders (infections, autoimmune/demyelinating diseases, lymphomas, and gliomas) to determine the potential utility of cytokine patterns in differentiating CNS infections from other CNS diseases. Both agglomerative hierarchical clustering and mixture discriminant analyses revealed grouping of CNS disease types based on cytokine expression. To further investigate the ability of CSF cytokine levels to distinguish various CNS disease states, non-parametric statistical analysis was performed. Mann-Whitney test analysis demonstrated that CNS infections are characterized by significantly higher CSF lP-10/CXCL10 levels than the pooled non-infectious CNS disorders (p = 0.0001). Within the infection group, elevated levels of MDC/CCL22 distinguished non-viral from viral infections (p = 0.0048). Each disease group of the non-infectious CNS disorders independently showed IP-10/CXCL10 levels that are significantly lower than the infection group [(autoimmune /demyelinating disorders (p = 0.0005), lymphomas (p = 0.0487), gliomas (p = 0.0294), and controls (p = 0.0001)]. Additionally, of the non-infectious diseases, gliomas can be distinguished from lymphomas by higher levels of GRO/CXCL1 (p = 0.0476), IL-7 (p = 0.0119), and IL-8 (p = 0.0460). Gliomas can also be distinguished from autoimmune/demyelinating disorders by higher levels of GRO/CXCL1 (p = 0.0044), IL-7 (p = 0.0035) and IL-8 (p = 0.0176). Elevated CSF levels of PDGF-AA distinguish lymphomas from autoimmune/demyelinating cases (p = 0.0130). Interrogation of the above comparisons using receiver operator characteristic analysis demonstrated area under the curve (AUC) values (ranging from 0.8636–1.0) that signify good to excellent utility as potential diagnostic discriminators. In conclusion, our work indicates that upon formal validation, measurement of CSF cytokine levels may have clinical utility in both identifying a CNS disorder as infectious in etiology and, furthermore, in distinguishing viral from non-viral CNS infections.

Efficacy and safety of monoclonal antibody therapies for relapsing remitting multiple sclerosis: A network meta-analysis

BACKGROUND

Several monoclonal antibodies have been licensed for relapsing remitting multiple sclerosis (RRMS). It is still unclear which treatment regimen should be recommended due to the lack of head-to-head randomized controlled trials (RCTs). This study aims to investigate the relative efficacy and safety of existing monoclonal antibody therapies in treating RRMS.

METHODS

We searched PubMed, Embase, and the Cochrane Library for RCTs of monoclonal antibodies for treatment of RRMS. We performed a network meta-analysis to identify evidence comparing monoclonal antibodies with one another, interferon beta-1a (INFβ-1a), or placebo in adult patients with RRMS. The primary efficacy outcome was annualized relapse rate and the primary safety outcome was incidence rate of serious adverse events.

RESULTS

A total of 14 eligible studies containing 9412 patients treated with 7 regimens were analyzed. INFβ-1a was the most common comparison treatment and showed an annualized relapse rate of 45.3%. All monoclonal antibody regimens, including natalizumab, natalizumab plus INFβ-1a, alemtuzumab, daclizumab, and ocrelizumab, were associated with significant reduction in annualized relapse rate and similar risks of serious adverse events. Cluster analysis showed that natalizumab plus INFβ-1a and alemtuzumab performed best in terms of high efficacy and safety. Natalizumab and daclizumab were characterized by high efficacy but relatively high risk of serious adverse events. Ocrelizumab was differentiated by high safety but relatively poor efficacy.

CONCLUSION

This network meta-analysis provided a comprehensive summary of efficacy and safety of monoclonal antibodies for RRMS, which might provide a reference for treatment. More direct comparison studies are warranted.

Signaling pathways and therapeutic perspectives related to environmental factors associated with multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated demyelinating disorder of unknown etiology. Both genetic-susceptibility and environment exposures, including vitamin D deficiency, Epstein-Barr viral and Herpesvirus (HHV-6) infections are strongly implicated in the activation of T cells and MS-pathogenesis. Despite precise knowledge of how these factors could be operating alone or in combination to facilitate and aggravate the disease progression, it is clear that prolonged induction of inflammatory molecules and recruitment of other immune cells by the activated T cells results in demyelination and axonal damage. It is imperative to understand the risk factors associated with MS progression and how these factors contribute to disease pathology. Understanding of the underlying mechanisms of what factors triggers activation of T cells to attack myelin antigen are important to strategize therapeutics and therapies against MS. Current review provides a detailed literature to understand the role of both pathogenic and non-pathogenic factors on the impact of MS.

Monoclonal antibodies in the treatment of multiple sclerosis: emergence of B-cell-targeted therapies

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS, and one of the most common causes of disability in young adults. Over the last decade, new disease-modifying therapies have emerged, including monoclonal antibodies (mAbs) that provide highly targeted therapies with greater efficacy than platform therapies. In particular, monoclonal antibodies directed against CD20-positive B cells have shown remarkable results in recent clinical trials and renewed interest in the mechanism of B cell-depleting therapies to ameliorate relapse activity and progression in MS. Here, we review the mechanisms of action and clinical evidence of approved and emerging mAbs, with a focus on B cell-targeted therapies.