Ocrelizumab in Patients with Active Primary Progressive Multiple Sclerosis: Clinical Outcomes and Immune Markers of Treatment Response

Multiple sclerosis: a narrative overview of current pharmacotherapies and emerging treatment prospects

Multiple sclerosis (MS) is a chronic autoimmune disease characterized by pathological processes of demyelination, subsequent axonal loss, and neurodegeneration within the central nervous system. Despite the availability of numerous disease-modifying therapies that effectively manage this condition, there is an emerging need to identify novel therapeutic targets, particularly for progressive forms of MS. Based on contemporary insights into disease pathophysiology, ongoing efforts are directed toward developing innovative treatment modalities. Primarily, monoclonal antibodies have been extensively investigated for their efficacy in influencing specific pathological pathways not yet targeted. Emerging approaches emphasizing cellular mechanisms, such as chimeric antigen receptor T cell therapy targeting immunological cells, are attracting increasing interest. The evolving understanding of microglia and the involvement of ferroptotic mechanisms in MS pathogenesis presents further avenues for targeted therapies. Moreover, innovative treatment strategies extend beyond conventional approaches to encompass interventions that target alterations in microbiota composition and dietary modifications. These adjunctive therapies hold promise as complementary methods for the holistic management of MS. This narrative review aims to summarize current therapies and outline potential treatment methods for individuals with MS.

How does Nogo-A signalling influence mitochondrial function during multiple sclerosis pathogenesis?

Multiple sclerosis (MS) is a severe neurological disorder that involves inflammation in the brain, spinal cord and optic nerve with key disabling neuropathological outcomes being axonal damage and demyelination. When degeneration of the axo-glial union occurs, a consequence of inflammatory damage to central nervous system (CNS) myelin, dystrophy and death can lead to large membranous structures from dead oligodendrocytes and degenerative myelin deposited in the extracellular milieu. For the first time, this review covers mitochondrial mechanisms that may be operative during MS-related neurodegenerative changes directly activated during accumulating extracellular deposits of myelin associated inhibitory factors (MAIFs), that include the potent inhibitor of neurite outgrowth, Nogo-A. Axonal damage may occur when Nogo-A binds to and signals through its cognate receptor, NgR1, a multimeric complex, to initially stall axonal transport and limit the delivery of important growth-dependent cargo and subcellular organelles such as mitochondria for metabolic efficiency at sites of axo-glial disintegration as a consequence of inflammation. Metabolic efficiency in axons fails during active demyelination and progressive neurodegeneration, preceded by stalled transport of functional mitochondria to fuel axo-glial integrity.

Alterations in the innate and adaptive immune system in a real-world cohort of multiple sclerosis patients treated with ocrelizumab

B cell depletion by the anti-CD20 antibody ocrelizumab is effective in relapsing-remitting (RR) and primary progressive (PP) multiple sclerosis (MS). We investigated immunological changes in peripheral blood of a real-world MS cohort after 6 and 12 months of ocrelizumab. All RRMS and most PPMS patients (15/20) showed treatment response. Ocrelizumab not only reduced CD20+ B cells, but also numbers of CD20+ T cells. Absolute numbers of monocytes, dendritic cells and CD8+ T cells were increased, while CD56hi natural killer cells were reduced after ocrelizumab. The residual B cell population shifted towards transitional and activated, IgA+ switched memory B cells, double negative B cells, and antibody-secreting cells. Delaying the treatment interval by 2-3 months increased mean B cell frequencies and enhanced naive B cell repopulation. Ocrelizumab reduced plasma levels of interleukin(IL)-12p70 and interferon(IFN)-α2. These findings will contribute to understanding ineffective treatment responses, dealing with life-threatening infections and further unravelling MS pathogenesis.

Immunomodulatory effects of ocrelizumab and candidate biomarkers for monitoring treatment response in multiple sclerosis

Ocrelizumab is a humanized monoclonal antibody designed to bind to the CD20 molecule, resulting in a rapid depletion of B-cells; however, it has been shown that lymphocyte subpopulations other than B-cells are affected by the drug. To review the effects of ocrelizumab on circulating lymphocytes and identify candidate biomarkers to predict and monitor treatment response. A literature search for the most relevant articles from 2006 to 2022 was conducted in PubMed and Scopus. The effect of ocrelizumab on the peripheral immune system goes beyond B-cells; it also depletes T CD20 + lymphocytes. Further, ocrelizumab reshapes the T-cell response toward a low inflammatory profile and induces an increase in T CD8 + regulatory cell percentage. A higher Body Mass Index and higher B-cell count at baseline have been associated with early B-cell reappearance. Serum neurofilament light chain reduction has been associated with treatment response. Ocrelizumab treatment exerts a broad immunomodulatory effect and may be tailored based on patients' clinical and biological profiles.

Current advances in the pharmacological prevention and management of cognitive dysfunction in multiple sclerosis

INTRODUCTION

Cognitive impairment (CI) is a core feature of Multiple Sclerosis (MS), being detectable in up to 65% of subjects. Treatment of CI can be considered of paramount importance. However, no standardized strategies are available to date to define the best treatment approach, especially for the pharmacological management.

AREAS COVERED

In this narrative review, the authors outline the latest advances in pharmacological management of CI in MS, including Disease Modifying Treatments (DMTs) which indirectly may or may not influence CI and symptomatic drugs. Selected publications were restricted to those written in English, reporting on an adult relapsing-remitting MS or progressive MS sample, assessing the effects of (at least) 1 DMT or treatment in a longitudinal design, reporting data on (at least) one standardized cognitive test performed at baseline and follow-up, and published between January 2018 and May 2022.

EXPERT OPINION

Recent data can be considered encouraging and inspiring for future studies. Overall, there is preliminary evidence of a beneficial effect of DMTs on cognition, particularly for high-efficacy DMTs. As for symptomatic treatments, dalfampridine appears to be the only medication with robust evidence of a positive effect on cognition. However, the definition of clinically meaningful change/improvement in cognitive functions remains an unmet need. Future studies should assess the role of other patient-related factors that can be associated with a better cognitive response to treatments and investigate the possible positive effect of multimodal interventions on cognition.