B cell depletion therapy does not resolve chronic active multiple sclerosis lesions

Re-defining progression in multiple sclerosis

PURPOSE OF REVIEW

The purpose of this article is to provide an overview of progression in multiple sclerosis (MS), including definitions, pathological mechanisms, and evidence that progressive biology begins early in the disease course.

RECENT FINDINGS

Definitions of MS clinical course have been refined to acknowledge the presence of both relapse and progression biology throughout the disease. Progression independent of relapse activity represents a significant proportion of disability worsening in relapsing-remitting MS (RRMS) disease. Progression in MS appears to be caused by the complex interplay of multiple processes, including nonresolving inflammation, microglial activation, oxidative stress, mitochondrial dysfunction, energetic failure, and neuro-axonal degeneration. These processes appear to begin in the earliest disease stages and their contribution to clinical phenotypes is dynamic over time. Promising results from clinical trials of tolebrutinib, in particular, underline the utility of targeting both innate and adaptive immune mechanisms to reduce disability accumulation.

SUMMARY

Pathological processes that underpin MS progression are detectable early in RRMS, evolve throughout the disease course and correlate with disability accumulation. Progression in MS should not be defined dichotomously - the focus instead should be on recognizing progressive components based on clinical measures and biomarkers early in the disease to better individualize treatment strategies.

Advances in neuroimaging of multiple sclerosis

PURPOSE OF REVIEW

To summarize recent advancements in understanding multiple sclerosis (MS) pathophysiology, predicting disease course, and monitoring treatment responses using MRI.

RECENT FINDINGS

Paramagnetic rim lesions (PRLs) are highly specific to MS and clinically relevant. Detected from the earliest disease phases, PRLs aid in distinguishing MS from other conditions, improving diagnostic accuracy. Moreover, PRLs are associated with more severe disability and measures of brain damage and may predict disease progression. Similarly, slowly expanding lesions (SELs) are associated with more severe disability and predict a more severe disease course. Disease-modifying therapies have limited effectiveness in reducing PRLs or SELs. Choroid plexus (CP) enlargement is associated with structural brain damage and clinical disability and predicts disease evolution. Enlarged perivascular spaces (ePVS) suggest microangiopathic changes rather than direct MS-related inflammation. Glymphatic dysfunction, evaluated using diffusion tensor image analysis along the perivascular space, emerges early in MS and correlates with disability, cognitive impairment, and structural brain damage. Aging and comorbidities exacerbate MS-related damage, complicating diagnosis and treatment. Emerging technologies, such as brain-age paradigms, aim to disentangle aging from MS-specific neurodegeneration.

SUMMARY

Advances in MRI have highlighted the clinical significance of chronic inflammation and glymphatic dysfunction as early contributors to MS progression as well as the interplay between aging, comorbidities and MS.

An update on the evaluation of treatment switching criteria in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a complex disorder driven by both inflammatory and neurodegenerative processes. While disease-modifying therapies (DMTs) have significantly improved prognosis, robust treatment switching criteria remain essential to balance efficacy and safety over the disease course.

AREAS COVERED

This review examines historical and current criteria for escalating DMTs from moderate- to high-efficacy therapies (HET). The authors summarize emerging clinical, imaging, and biological markers that inform decision-making and explore strategies for de-escalation, including DMT discontinuation and innovative approaches such as exit and bridge therapies.

EXPERT OPINION

Recent advances in MS management emphasize earlier initiation of HET and more stringent switching criteria. Although innovative monitoring tools - including clinical evaluations, imaging, biological markers, and patient-reported outcomes (PROs) - enhance disease assessment, they require further validation, standardization, and broader accessibility. Similarly, de-escalation criteria need additional research to optimize patient selection.

Impact of oral Cladribine on paramagnetic rim lesions of Multiple Sclerosis patients

BACKGROUND

Paramagnetic rim lesions (PRLs), marked by chronic inflammation and iron-loaded microglia, are linked to severe disease progression in multiple sclerosis (MS). The impact of cladribine, an immune reconstitution therapy, on PRLs remains underexplored.

OBJECTIVE

To evaluate the effect of cladribine tablets on PRLs in relapsing-remitting MS (RRMS) patients and explore the association between PRLs dynamics and brain atrophy.

METHODS

We conducted a retrospective analysis of 52 RRMS patients treated with cladribine in Buenos Aires between 2018 and 2021. Brain MRIs were analyzed at baseline, 12, and 24 months post-treatment, focusing on PRLs count and brain volume measurements. Statistical analyses included Wilcoxon tests, Poisson mixed models, and linear mixed models.

RESULTS

The cohort included 52 patients (32 women) with a median age of 36 years (range 21-66 years). PRLs were present in 61.5% of patients at baseline. Cladribine treatment significantly reduced PRLs count (IRR=0.68, 95% CI [0.49, 0.95], p=0.02), independent of prior treatment or disease activity. While no significant relationship was found between PRLs changes and overall brain atrophy, a significant interaction between PRLs dynamics and atrophy in the right thalamus was observed (p<0.05).

CONCLUSION

Cladribine tablets are associated with a reduction in PRLs in RRMS patients, potentially influencing regional brain atrophy over time.

Neurodegeneration correlates of iron-related lesions and leptomeningeal inflammation in multiple sclerosis clinical subtypes

PURPOSE

The aim of this study was to investigate the significant implications of different types of lesions as assessed by QSM (quantitative-susceptibility-mapping) as well as leptomeningeal contrast-enhancement in a cohort of Relapsing-Remitting (RR) and Primary Progressive (PP) MS patients and to assess their association with clinical disability and MRI-measures of brain structural damage.

METHODS

Different types of white-matter lesions were identified and quantified using QSM in 24 RRMS and 15 PPMS (11 patients with follow-up MRI). Leptomeningeal contrast-enhancement (LMCE; foci) was assessed on 3D-FLAIR post-gadolinium.

RESULTS

Both RRMS and PPMS presented PRL (paramagnetic-rim lesions) and LMCE, with PPMS showing a trend towards more LMCE (RRMS 37%, PPMS 53%). In QSM RRMS patients showed more hyperintense white-matter lesions with greater lesion volume. In RRMS PRL correlated with disease duration and lesion burden especially the volume of juxtacortical Flair-hyperintense lesions. Besides, the presence of PRL lesions in PPMS was associated with subcortical atrophy mainly thalamus and pallidum volumetry. In all MS-cohort, patients with more than 3-PRLs exhibited reduced regional cortical thickness in specific temporal areas and post/para central gyrus. Forest-analysis selected age, increased NAWM (normal appearing white-matter) QSM intensity, total lesion volume and the presence of LMCE as informative predictors of cortical thickness. After anti-CD20 treatment, no significant change was observed regarding the number of PRL and LMCE, but the percentage of PRL lesions over the total lesion types and the QSM rim intensity increased.

CONCLUSION

Our findings suggest that QSM-lesion types and leptomeningeal inflammation capture different aspects of progressive disease biology in both RRMS and PPMS.

Current state and perspectives of CAR T cell therapy in central nervous system diseases

B cell-directed CAR T cell therapy has fundamentally changed the treatment of haematological malignancies, and its scope of application is rapidly expanding to include other diseases such as solid tumours or autoimmune disorders. Therapy-refractoriness remains an important challenge in various inflammatory and non-inflammatory disorders of the CNS. The reasons for therapy failure are diverse and include the limited access current therapies have to the CNS, as well as enormous inter- and intra-individual disease heterogeneity. The tissue-penetrating properties of CAR T cells make them a promising option for overcoming this problem and tackling pathologies directly within the CNS. First application of B cell-directed CAR T cells in neuromyelitis optica spectrum disorder and multiple sclerosis patients has recently revealed promising outcomes, expanding the potential of CAR T cell therapy to encompass CNS diseases. Additionally, the optimization of CAR T cells for the therapy of gliomas is a growing field. As a further prospect, preclinical data reveal the potential benefits of CAR T cell therapy in the treatment of primary neurodegenerative diseases such as Alzheimer's disease. Considering the biotechnological optimizations in the field of T cell engineering, such as extension to target different antigens or variation of the modified T cell subtype, new and promising fields of CAR T cell application are rapidly opening up. These innovations offer the potential to address the complex pathophysiological properties of CNS diseases. To use CAR T cell therapy optimally to treat CNS diseases in the future while minimizing therapy risks, further mechanistic research and prospective controlled trials are needed to assess seriously the disease and patient-specific risk-benefit ratio.

Paramagnetic rim lesion formation is predicted by the initial gadolinium-enhancing lesion diameter

BACKGROUND

Paramagnetic rim lesions (PRLs) are a magnetic resonance imaging (MRI) marker of compartmentalized intraparenchymal inflammation.

OBJECTIVES

The primary objective was to investigate clinical, demographic, and MRI factors that may be predictive of the future formation of PRL.

METHODS

This is a retrospective analysis of longitudinal data. Patients were included if they had ⩾1 gadolinium-enhancing lesion on any historical MRI and follow-up scan(s) ⩾6 months afterward on a standardized 3T MRI using the filtered phase component of a susceptibility-sensitive sequence ("SWAN"). Regression and machine-learning models were used to identify the predictive ability of demographic, clinical, immunological, treatment-related, and MRI predictors of PRL formation.

RESULTS

A total of 64 patients having 229 contrast-enhancing lesions (CELs) were included. Among all predictors, the diameter of the initial enhancing lesion was the most influential for determining subsequent PRL formation; every millimeter increase in diameter increased the risk of PRL formation by 44%. Other factors did not contribute additional information; the administration of steroids was not associated with any effect.

CONCLUSIONS

The long-axis diameter of a CEL is the best translational predictor of subsequent PRL formation at follow-up. This measure holds promise as a method to identify patients at high risk of chronic active lesion formation during the acute inflammatory window.

Brain lesion characteristics in Chinese multiple sclerosis patients: A 7-T MRI cohort study

OBJECTIVE

Prevalence, susceptibility genes, and clinical and radiological features may differ across different ethnic groups of multiple sclerosis (MS). We aim to characterize brain lesions in Chinese patients with MS by use of 7-T MRI.

METHODS

MS participants were enrolled from the ongoing China National Registry of Neuro-Inflammatory Diseases (CNRID) cohort. 7-T MRI of the brain was performed. Each lesion was evaluated according to a standardized procedure. Central vein sign (CVS) and paramagnetic rim lesions were identified. The characteristics of lesions at patient-level and at lesion-level from previous 7-T MRI literature were also summarized.

RESULTS

We included 120 MS patients. Their mean (SD) age was 34.6 (9.4) years. The female-to-male ratio was 1.7:1 and mean disease duration of patients with MS was 5.5 ± 6.1 years. The median EDSS score was 2 (range, 0-8). A total of 8502 lesions were identified with a median lesion count of 45 (IQR, 18-90) (range, 2-370). The median (IQR) percentage for these special locations were as follows: cortical lesions (CLs) 2.7% (0%-5.7%), juxtacortical lesions 16.2% (7.8%-25.7%), periventricular lesions 30.2% (17.2%-38.7%), and infratentorial lesions 5.8% (0.4%-11.9%). CLs occurred in 70 (58%) patients, accounting for only 443 (5%) of the total lesions. Out of the 443 CLs, 309 (69.8%) were leukocortical lesions. CVS appeared in 5392 (63%) lesions from 117 (98%) patients. 1792 (21%) lesions and 104 (87%) patients exhibited a paramagnetic rim.

INTERPRETATION

Our study elaborated on the lesion features of Chinese patients with MS by use of 7-T MRI. Lesion burden is heavy in Chinese patients with MS. The median lesion count and proportion of PRL are high. The reported heavy lesion burden calls for ramping up regional and global efforts to care for MS patients. The management and research of Chinese population with MS needs to be further strengthened.

Reliability of paramagnetic rim lesion detection at 1.5T MRI in multiple sclerosis patients

BACKGROUND

Paramagnetic rim lesions (PRL) are valuable for diagnosing and prognosing multiple sclerosis (MS) and detectable at 7T and 3T MRI. For translation into clinical practice, it is essential assessing their visibility on 1.5T clinical scanners.

OBJECTIVE

To evaluate the reliability of detecting PRL using commercially available susceptibility-weighted imaging (SWI) at 1.5 versus 3T MRI.

METHODS

SWI images were obtained in 20 people with MS at 1.5T and 3T MRI, with an average scan interval of 1.1 years. Only stable, non-enhancing lesions visible on both scans were analyzed. PRL at 3T were identified by two expert raters using NAIMS PRL criteria and used as a reference. Four raters, blinded to 3T results, assessed PRL at 1.5T. Discrepancies were resolved by consensus.

RESULTS

PRL were identified in 16 of 20 patients. At 3T, 95 PRL were identified by consensus (mean 5 PRL per patient, range 0-30). Blinded to 3T scans, 82% of PRL were visible at 1.5T (78 of 95 PRL). Interrater reliability was "almost perfect" for both 1.5 and 3T scans. Raters accurately classified all patients as having ⩾1PRL or not at 1.5T.

CONCLUSION

The majority of PRL are detectable at 1.5T without significantly reducing the specificity of PRL identification or increasing the detection of pseudo-PRL. This may facilitate their clinical use in MS diagnosis and prognosis.

Cognitive changes in patients with relapse-free MS treated with high efficacy therapies: the predictive value of paramagnetic rim lesions

BACKGROUND

High-efficacy disease-modifying therapies (HETs) have substantially improved multiple sclerosis (MS) management, yet ongoing cognitive decline remains a concern. This study aims to assess Symbol Digit Modalities Test (SDMT) changes in patients with stable relapsing-remitting MS (RRMS) treated with HETs and to evaluate the role of baseline MRI biomarkers as predictors of SDMT changes.

METHODS

Consecutive patients with RRMS treated with HETs underwent clinical, SDMT and MRI assessment at baseline with SDMT and clinical re-evaluation after 24 months. Patients presenting relapses or MRI activity (new T2 and/or gadolinium-enhancing lesions) during follow-up were excluded. Cognitive changes were defined using the 90% CI regression-based reliable change index methodology accounting for sex, age, education and baseline score. Baseline MRI examination included three-dimensional-sagittal Fluid Attenuated Inversion Recovery (FLAIR), T1-Magnetization Prepared - RApid Gradient Echo (T1-MPRAGE) and quantitative susceptibility mapping (QSM) for paramagnetic rim lesions (PRLs) and QSM-isointense lesions (ISO) assessment. Univariate and multivariable regression analyses were performed to predict SDMT changes.

RESULTS

90 patients (mean age: 40.3 years, median Expanded Disability Status Scale: 2.0) were included. PRLs were present in 46 (51.1%) patients. After 24 months, 13 (14.4%) patients showed SDMT decline and 8 (8.9%) showed improvement. At multivariable analyses, PRLs were associated with higher risk of SDMT decline (β: 2.70, p: 0.02, OR: 14.82) while higher ISO lesion volumes were weakly associated with SDMT improvement (β: 0.07, p: 0.01, OR: 1.07).

CONCLUSIONS

SDMT decline and improvement are detectable in patients with RRMS without clinical or MRI activity over 2 years. PRLs seem to predict SDMT decline in MS, underscoring the critical role of compartmentalised chronic inflammation in disease progression.

A Window into New Insights on Progression Independent of Relapse Activity in Multiple Sclerosis: Role of Therapies and Current Perspective

In multiple sclerosis (MS), there is significant evidence indicating that both progression independent of relapse activity (PIRA) and relapse-related worsening events contribute to the accumulation of progressive disability from the onset of the disease and throughout its course. Understanding the compartmentalized pathophysiology of MS would enhance comprehension of disease progression mechanisms, overcoming the traditional distinction in phenotypes. Smoldering MS activity is thought to be maintained by a continuous interaction between the parenchymal chronic processes of neuroinflammation and neurodegeneration and the intrathecal compartment. This review provides a comprehensive and up-to-date overview of the neuropathological and immunological evidence related to the mechanisms underlying PIRA phenomena in MS, with a focus on studies investigating the impact of currently available therapies on these complex mechanisms.

Exploring the Pathophysiology, Diagnosis, and Treatment Options of Multiple Sclerosis

The complicated neurological syndrome known as multiple sclerosis (MS) is typified by demyelination, inflammation, and neurodegeneration in the central nervous system (CNS). Managing this crippling illness requires an understanding of the complex interactions between neurophysiological systems, diagnostic techniques, and therapeutic methods. A complex series of processes, including immunological dysregulation, inflammation, and neurodegeneration, are involved in the pathogenesis of MS. Gene predisposition, autoreactive T cells, B cells, and cytokines are essential participants in the development of the disease. Demyelination interferes with the ability of the CNS to transmit signals, which can cause a variety of neurological symptoms, including impaired motor function, sensory deficiencies, and cognitive decline. Developing tailored therapeutics requires understanding the underlying processes guiding the course of the disease. Neuroimaging, laboratory testing, and clinical examination are all necessary for an accurate MS diagnosis. Evoked potentials and cerebrospinal fluid studies assist in verifying the diagnosis, but magnetic resonance imaging (MRI) is essential for identifying distinctive lesions in the CNS. Novel biomarkers have the potential to increase diagnostic precision and forecast prognosis. The goals of MS treatment options are to control symptoms, lower disease activity, and enhance quality of life. To stop relapses and reduce the course of the disease, disease-modifying treatments (DMTs) target several components of the immune response. DMTs that are now on the market include interferons, glatiramer acetate, monoclonal antibodies, and oral immunomodulators; each has a unique mode of action and safety profile. Symptomatic treatments improve patients' general well-being by addressing specific symptoms, including pain, sphincter disorders, fatigue, and spasticity. Novel treatment targets, neuroprotective tactics, and personalized medicine techniques will be the main focus of MS research in the future. Improving long-term outcomes for MS patients and optimizing disease treatment may be possible by utilizing immunology, genetics, and neuroimaging developments. This study concludes by highlighting the complexity of multiple MS, including its changing therapeutic landscape, diagnostic problems, and neurophysiological foundations. A thorough grasp of these elements is essential to improving our capacity to identify, manage, and eventually overcome this intricate neurological condition.

Ofatumumab for multiple sclerosis with disability accumulation

BACKGROUND

The ASCLEPIOS/APLIOS/APOLITOS/ALITHIOS trials highlighted the benefits of ofatumumab in reducing relapse rates and disability progression in multiple sclerosis (MS). However, its effects on patients with severe disability status remains uncertain. This study aimed to clarify the outcomes of ofatumumab in MS patients with high Expanded Disability Status Scale (EDSS) scores and prolonged disease durations.

METHODS

This is a retrospective cohort study of MS patients treated with ofatumumab at an MS center in Japan. At 12 months of treatment, patients with MS starting ofatumumab were classified into the treatment-responsive or treatment-resistant groups based on ofatumumab continuity, incidence of relapses with EDSS worsening, progression independent of relapse activity (PIRA). We used logistic regression analysis to identify factors associated with ofatumumab response.

RESULTS

Seventy patients were included in the analysis; 39 (56 %) patients were relapsing-remitting (RR), and 31 (44 %) patients were secondary progressive (SP) MS. Mean age at ofatumumab initiation, age at onset, and disease duration were 48.0, 33.9, and 14.1 years, respectively. The median EDSS was 4.5 (3.0-6.5); 38(56 %) patients were classified as resistant. The resistant rates by disease type were 33 % (13/39) and 81 % (26/31) for RR and SP MS, respectively. On multivariate analysis, EDSS and No evidence of disease activity (NEDA) 3 were independent factors for ofatumumab responsiveness (OR, 1.74, 0.04; 95 % CI, 1.17-2.73, 0.00-0.47; p = 0.01, 0.04).

CONCLUSION

Ofatumumab may yield more favorable effects when initiated in patients with MS with lower EDSS scores.

TSPO-PET Reveals Higher Inflammation in White Matter Disrupted by Paramagnetic Rim Lesions in Multiple Sclerosis

Objective

To explore whether the inflammatory activity is higher in white matter (WM) tracts disrupted by paramagnetic rim lesions (PRLs) and if inflammation in PRL-disrupted WM tracts is associated with disability in people with multiple sclerosis (MS).

Methods

Forty-four MS patients and 16 healthy controls were included. 18 kDa-translocator protein positron emission tomography (TSPO-PET) with the 11C-PK11195 radioligand was used to measure the neuroinflammatory activity. The Network Modification Tool was used to identify WM tracts disrupted by PRLs and non-PRLs that were delineated on MRI. The Expanded Disability Status Scale was used to measure disability.

Results

MS patients had higher inflammatory activity in whole brain WM compared to healthy controls (p=0.001). Compared to patients without PRLs, patients with PRLs exhibited higher levels of inflammatory activity in the WM tracts disrupted by any type of lesions (p=0.02) or PRLs (p=0.004). In patients with at least one PRL, inflammatory activity was higher in WM tracts highly disrupted by PRLs compared to WM tracts highly disrupted by non-PRLs (p=0.009). Elevated inflammatory activity in highly disrupted WM tracts was associated with increased disability in patients with PRL (p=0.03), but not in patients without PRL (p=0.2).

Interpretation

This study suggests that patients with PRLs may exhibit more diffuse WM inflammation in addition to higher inflammation along WM tracts disrupted by PRLs compared to non-PRLs, which could contribute to larger lesion volumes and faster disability progression. Imaging PRLs may serve to identify patients with both focal and diffuse inflammation, guiding therapeutic interventions aimed at reducing inflammation and preventing progressive disability in MS.

Chronic active lesions in multiple sclerosis: classification, terminology, and clinical significance

In multiple sclerosis (MS), increasing disability is considered to occur due to persistent, chronic inflammation trapped within the central nervous system (CNS). This condition, known as smoldering neuroinflammation, is present across the clinical spectrum of MS and is currently understood to be relatively resistant to treatment with existing disease-modifying therapies. Chronic active white matter lesions represent a key component of smoldering neuroinflammation. Initially characterized in autopsy specimens, multiple approaches to visualize chronic active lesions (CALs) in vivo using advanced neuroimaging techniques and postprocessing methods are rapidly emerging. Among these in vivo imaging correlates of CALs, paramagnetic rim lesions (PRLs) are defined by the presence of a perilesional rim formed by iron-laden microglia and macrophages, whereas slowly expanding lesions are identified based on linear, concentric lesion expansion over time. In recent years, several longitudinal studies have linked the occurrence of in vivo detected CALs to a more aggressive disease course. PRLs are highly specific to MS and therefore have recently been incorporated into the MS diagnostic criteria. They also have prognostic potential as biomarkers to identify patients at risk of early and severe disease progression. These developments could significantly affect MS care and the evaluation of new treatments. This review describes the latest knowledge on CAL biology and imaging and the relevance of CALs to the natural history of MS. In addition, we outline considerations for current and future in vivo biomarkers of CALs, emphasizing the need for validation, standardization, and automation in their assessment.

Programming tissue-sensing T cells that deliver therapies to the brain

To engineer cells that can specifically target the central nervous system (CNS), we identified extracellular CNS-specific antigens, including components of the CNS extracellular matrix and surface molecules expressed on neurons or glial cells. Synthetic Notch receptors engineered to detect these antigens were used to program T cells to induce the expression of diverse payloads only in the brain. CNS-targeted T cells that induced chimeric antigen receptor expression efficiently cleared primary and secondary brain tumors without harming cross-reactive cells outside of the brain. Conversely, CNS-targeted cells that locally delivered the immunosuppressive cytokine interleukin-10 ameliorated symptoms in a mouse model of neuroinflammation. Tissue-sensing cells represent a strategy for addressing diverse disorders in an anatomically targeted manner.

Emerging MRI biomarkers for the diagnosis of multiple sclerosis

The need to improve diagnostic precision in multiple sclerosis (MS) is widely recognized. In recent years, several novel magnetic resonance imaging (MRI) biomarkers have been proposed to enhance diagnostic specificity and reduce misdiagnosis. Some of these imaging biomarkers are deemed highly specific for MS and are likely ready to enter the MS diagnostic work-up, while others are still in their exploratory phase. In addition, new synthetic MRI contrasts and artificial intelligence-based diagnostic algorithms are being tested to reduce the time burden related to imaging data acquisition and analysis. In this review, we summarize the most recent advancement in the field, focusing on the adoption of these novel MRI biomarkers-whether used alone or in combination-for the differential diagnosis of MS.

Clinical relevance of paramagnetic rim lesion heterogeneity in multiple sclerosis

OBJECTIVE

Previous studies reveal heterogeneity in terms of paramagnetic rim lesions (PRL) associated tissue damage. We investigated the physiopathology and clinical implications of this heterogeneity.

METHODS

In 103 MS patients (72 relapsing and 31 progressive), brain lesions were manually segmented on 3T 3D-FLAIR and rim visibility was assessed with a visual confidence level score (VCLS) on 3D-EPI phase. Using T1 relaxation time maps, lesions were categorized in long-T1 and short-T1. Lesion age was calculated from time of first gadolinium enhancement (N = 84 lesions). Results on clinical scores were validated in an extended cohort of 167 patients using normalized T1w-MPRAGE lesion values.

RESULTS

Rim visibility (VCLS analysis) was associated with increasing lesional T1 (P/PFDR < 0.001). Of 1680 analyzed lesions, 427 were categorized as PRL. Long-T1 PRL were older than short-T1 PRL (average 0.8 vs. 2.0 years, P/PFDR = 0.005/0.008), and featured larger lesional volume (P/PFDR < 0.0001) and multi-shell diffusion-measured axonal damage (P/PFDR < 0.0001). The total volume of long-T1-PRL versus PRL showed 2× predictive power for both higher MS disability (EDSS; P/PFDR = 0.003/0.005 vs. P/PFDR = 0.042/0.057) and severity (MSSS; P/PFDR = 0.0006/0.001 vs. P/PFDR = 0.004/0.007). In random forest, having ≥1 long-T1-PRL versus ≥4 PRL showed 2-4× higher performance to predict a higher EDSS and MSSS. In the validation cohort, long-T1 PRL outperformed (~2×) PRL in predicting both EDSS and MSSS.

INTERPRETATION

PRL show substantial heterogeneity in terms of intralesional tissue damage. More destructive, likely older, long-T1 PRL improve the association with MS clinical scales. This PRL heterogeneity characterization was replicated using standard T1w MRI, highlighting its potential for clinical translation.

Imaging Outcomes for Phase 2 Trials Targeting Compartmentalized Inflammation

This comprehensive review aims to explore imaging outcome measures targeting compartmentalized inflammation in Phase 2 clinical trials for multiple sclerosis (MS). The traditional primary imaging outcomes used in Phase 2 MS trials, new or enhancing white matter lesions on MRI, target the effects of peripheral inflammation, but the widespread inflammation behind a mostly closed blood-brain barrier is not captured. This review discusses several emerging imaging technologies that could be used as surrogate markers of compartmentalized inflammation, targeting chronic active lesions, meningeal inflammation, and innate immune activation within the normal-appearing white matter and gray matter. The integration of specific imaging outcomes into Phase 2 trials can provide a more accurate assessment of treatment efficacy, ultimately contributing to the development of more effective therapies for MS.

Targeting cytokine networks in neuroinflammatory diseases

In neuroinflammatory diseases, systemic (blood-borne) leukocytes invade the central nervous system (CNS) and lead to tissue damage. A causal relationship between neuroinflammatory diseases and dysregulated cytokine networks is well established across several preclinical models. Cytokine dysregulation is also observed as an inadvertent effect of cancer immunotherapy, where it often leads to neuroinflammation. Neuroinflammatory diseases can be separated into those in which a pathogen is at the centre of the immune response and those of largely unknown aetiology. Here, we discuss the pathophysiology, cytokine networks and therapeutic landscape of 'sterile' neuroinflammatory diseases such as multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), neurosarcoidosis and immune effector cell-associated neurotoxicity syndrome (ICANS) triggered by cancer immunotherapy. Despite successes in targeting cytokine networks in preclinical models of neuroinflammation, the clinical translation of targeting cytokines and their receptors has shown mixed and often paradoxical responses.

The use of 7T MRI in multiple sclerosis: review and consensus statement from the North American Imaging in Multiple Sclerosis Cooperative

The use of ultra-high-field 7-Tesla (7T) MRI in multiple sclerosis (MS) research has grown significantly over the past two decades. With recent regulatory approvals of 7T scanners for clinical use in 2017 and 2020, the use of this technology for routine care is poised to continue to increase in the coming years. In this context, the North American Imaging in MS Cooperative (NAIMS) convened a workshop in February 2023 to review the previous and current use of 7T technology for MS research and potential future research and clinical applications. In this workshop, experts were tasked with reviewing the current literature and proposing a series of consensus statements, which were reviewed and approved by the NAIMS. In this review and consensus paper, we provide background on the use of 7T MRI in MS research, highlighting this technology's promise for identification and quantification of aspects of MS pathology that are more difficult to visualize with lower-field MRI, such as grey matter lesions, paramagnetic rim lesions, leptomeningeal enhancement and the central vein sign. We also review the promise of 7T MRI to study metabolic and functional changes to the brain in MS. The NAIMS provides a series of consensus statements regarding what is currently known about the use of 7T MRI in MS, and additional statements intended to provide guidance as to what work is necessary going forward to accelerate 7T MRI research in MS and translate this technology for use in clinical practice and clinical trials. This includes guidance on technical development, proposals for a universal acquisition protocol and suggestions for research geared towards assessing the utility of 7T MRI to improve MS diagnostics, prognostics and therapeutic efficacy monitoring. The NAIMS expects that this article will provide a roadmap for future use of 7T MRI in MS.

Imaging chronic active lesions in multiple sclerosis: a consensus statement

Chronic active lesions (CAL) are an important manifestation of chronic inflammation in multiple sclerosis and have implications for non-relapsing biological progression. In recent years, the discovery of innovative MRI and PET-derived biomarkers has made it possible to detect CAL, and to some extent quantify them, in the brain of persons with multiple sclerosis, in vivo. Paramagnetic rim lesions on susceptibility-sensitive MRI sequences, MRI-defined slowly expanding lesions on T1-weighted and T2-weighted scans, and 18-kDa translocator protein-positive lesions on PET are promising candidate biomarkers of CAL. While partially overlapping, these biomarkers do not have equivalent sensitivity and specificity to histopathological CAL. Standardization in the use of available imaging measures for CAL identification, quantification and monitoring is lacking. To fast-forward clinical translation of CAL, the North American Imaging in Multiple Sclerosis Cooperative developed a consensus statement, which provides guidance for the radiological definition and measurement of CAL. The proposed manuscript presents this consensus statement, summarizes the multistep process leading to it, and identifies the remaining major gaps in knowledge.

Lesion phenotyping based on magnetic susceptibility in pediatric multiple sclerosis

BACKGROUND AND PURPOSE

Pediatric multiple sclerosis (MS) displays different pathological features compared to adult MS, which can be studied in vivo by assessing tissue magnetic susceptibility with 3T-MRI. We aimed to assess different white matter lesions (WMLs) phenotypes in pediatric MS patients using quantitative susceptibility mapping (QSM) and susceptibility mapping weighted imaging (SMWI) over 12 months.

METHODS

Eleven pediatric MS patients [female: 63.6%; mean ± standard deviation (SD) age and disease duration: 16.3 ± 2.2 and 2.4 ± 1.5; median (range) Expanded Disability Status Scale (EDSS) 1 (0-2)] underwent 3 Tesla-MRI exams and EDSS assessments at baseline and after 1 year. QSM and SMWI were obtained using 3-dimensional (3D)-segmented echo-planar-imaging with submillimetric spatial resolution. WMLs were classified according to their QSM appearance and SMWI was used to identify QSM hyperintensities ascribable to veins. Total brain volumes at baseline and follow-up were computed using high-resolution 3D T1-weighted images.

RESULTS

Mean ± SD paramagnetic rim lesions (PRLs) prevalence was 7.0% ± 9.0. Fifty-four percent (6/11) of patients exhibited at least one PRL, with one patient exhibiting ≥ 4 PRLs. All patients showed QSM-iso-/hypo-intense lesions, which represented a mean ± SD of 65.8% ± 22.7 of total WMLs. QSM-hyperintense WMLs showed a positive correlation with total brain volume reduction at follow-up (r = 0.705; p =  .02). No lesion was classified as different between baseline and follow-up.

CONCLUSION

Chronic compartmentalized inflammation seems to occur early in pediatric MS patients with short disease duration. A high prevalence of iso-/hypo-intense lesions was found, which could account for the higher remyelination potential in pediatric MS.

A comparison of natalizumab and ocrelizumab on disease progression in multiple sclerosis

OBJECTIVE

No direct comparisons of the effect of natalizumab and ocrelizumab on progression independent of relapse activity (PIRA) and relapse-associated worsening (RAW) events are currently available. We aimed to compare the risk of achieving first 6 months confirmed PIRA and RAW events and irreversible Expanded Disability Status Scale (EDSS) 4.0 and 6.0 in a cohort of naïve patients treated with natalizumab or ocrelizumab from the Italian Multiple Sclerosis Register.

METHODS

Patients with a first visit within 1 year from onset, treated with natalizumab or ocrelizumab, and ≥3 visits were extracted. Pairwise propensity score-matched analyses were performed. Risk of reaching the first PIRA, RAW, and EDSS 4.0 and 6.0 events were estimated using multivariable Cox proportional hazards models. Kaplan-Meier curves were used to show cumulative probabilities of reaching outcomes.

RESULTS

In total, 770 subjects were included (natalizumab = 568; ocrelizumab = 212) and the propensity score-matching retrieved 195 pairs. No RAW events were found in natalizumab group and only 1 was reported in ocrelizumab group. A first PIRA event was reached by 23 natalizumab and 25 ocrelizumab exposed patients; 7 natalizumab- and 10 ocrelizumab-treated patients obtained an irreversible EDSS 4.0, while 13 natalizumab- and 15 ocrelizumab-treated patients reached an irreversible EDSS 6.0. No differences between the two groups were found in the risk (HR, 95%CI) of reaching a first PIRA (1.04, 0.59-1.84; p = 0.88) event, an irreversible EDSS 4.0 (1.23, 0.57-2.66; p = 0.60) and 6.0 (0.93, 0.32-2.68; p = 0.89).

INTERPRETATION

Both medications strongly suppress RAW events and, in the short term, the risk of achieving PIRA events, EDSS 4.0 and 6.0 milestones is not significantly different.

New Imaging Markers in Multiple Sclerosis and Related Disorders: Smoldering Inflammation and the Central Vein Sign

Concepts of multiple sclerosis (MS) biology continue to evolve, with observations such as "progression independent of disease activity" challenging traditional phenotypic categorization. Iron-sensitive, susceptibility-based imaging techniques are emerging as highly translatable MR imaging sequences that allow for visualization of at least 2 clinically useful biomarkers: the central vein sign and the paramagnetic rim lesion (PRL). Both biomarkers demonstrate high specificity in the discrimination of MS from other mimics and can be seen at 1.5 T and 3 T field strengths. Additionally, PRLs represent a subset of chronic active lesions engaged in "smoldering" compartmentalized inflammation behind an intact blood-brain barrier.

[XVI Post-ECTRIMS Meeting: review of the new developments presented at the 2023 ECTRIMS Congress (I)]

The XVI Post-ECTRIMS meeting took place in Seville on 20 and 21 October 2023. This meeting was attended by neurologists specialising in multiple sclerosis (MS) from Spain, who shared a summary of the most interesting innovations at the ECTRIMS congress, which had taken place in Milan the previous week. The aim of this article is to summarise new developments related to the pathogenesis, diagnosis and prognosis of MS. The contributions of innate immunity and central nervous system resident cells, including macrophages and microglia in MS pathophysiology and as therapeutic targets were discussed. Compartmentalised intrathecal inflammation was recognised as central to understanding the progression of MS, and the relationship between inflammatory infiltrates and disease progression was highlighted. Perspectives in demyelinating pathologies were reviewed, focusing on neuromyelitis optica and myelin oligodendrocyte glycoprotein antibody-associated disease, highlighting their pathophysiological and diagnostic differences compared to MS. Advances in neuroimaging were also discussed, and especially the analysis of active chronic lesions, such as paramagnetic rim lesions. In the absence of clinical improvements in trials of remyelinating treatments, methodological strategies to optimise the design of future studies were proposed. Breakthroughs in detecting the prodromal phase of MS, the use of biomarkers in body fluids to assess activity, progression and treatment response, and research on progression independent of flares were addressed. The need to define criteria for radiologically isolated syndrome and to clarify the concept was also discussed.

Central Vein Sign, Cortical Lesions, and Paramagnetic Rim Lesions for the Diagnostic and Prognostic Workup of Multiple Sclerosis

BACKGROUND AND OBJECTIVES

The diagnosis of multiple sclerosis (MS) can be challenging in clinical practice because MS presentation can be atypical and mimicked by other diseases. We evaluated the diagnostic performance, alone or in combination, of the central vein sign (CVS), paramagnetic rim lesion (PRL), and cortical lesion (CL), as well as their association with clinical outcomes.

METHODS

In this multicenter observational study, we first conducted a cross-sectional analysis of the CVS (proportion of CVS-positive lesions or simplified determination of CVS in 3/6 lesions-Select3*/Select6*), PRL, and CL in MS and non-MS cases on 3T-MRI brain images, including 3D T2-FLAIR, T2*-echo-planar imaging magnitude and phase, double inversion recovery, and magnetization prepared rapid gradient echo image sequences. Then, we longitudinally analyzed the progression independent of relapse and MRI activity (PIRA) in MS cases over the 2 years after study entry. Receiver operating characteristic curves were used to test diagnostic performance and regression models to predict diagnosis and clinical outcomes.

RESULTS

The presence of ≥41% CVS-positive lesions/≥1 CL/≥1 PRL (optimal cutoffs) had 96%/90%/93% specificity, 97%/84%/60% sensitivity, and 0.99/0.90/0.77 area under the curve (AUC), respectively, to distinguish MS (n = 185) from non-MS (n = 100) cases. The Select3*/Select6* algorithms showed 93%/95% specificity, 97%/89% sensitivity, and 0.95/0.92 AUC. The combination of CVS, CL, and PRL improved the diagnostic performance, especially when Select3*/Select6* were used (93%/94% specificity, 98%/96% sensitivity, 0.99/0.98 AUC; p = 0.002/p < 0.001). In MS cases (n = 185), both CL and PRL were associated with higher MS disability and severity. Longitudinal analysis (n = 61) showed that MS cases with >4 PRL at baseline were more likely to experience PIRA at 2-year follow-up (odds ratio 17.0, 95% confidence interval: 2.1-138.5; p = 0.008), whereas no association was observed between other baseline MRI measures and PIRA, including the number of CL.

DISCUSSION

The combination of CVS, CL, and PRL can improve MS differential diagnosis. CL and PRL also correlated with clinical measures of poor prognosis, with PRL being a predictor of disability accrual independent of clinical/MRI activity.

Enlarged perivascular spaces are associated with brain microangiopathy and aging in multiple sclerosis

BACKGROUND

Growing evidence links brain-MRI enlarged perivascular spaces (EPVS) and multiple sclerosis (MS), but their role remains unclear.

OBJECTIVE

This study aimed to investigate the cross-sectional associations of EPVS with several neuroinflammatory and neurodegenerative features in a large multicentric-MS cohort.

METHODS

In total, 207 patients underwent 3T axial-T2-weighted brain-MRI for EPVS assessment (EPVS dichotomized into high/low according to ⩾ 2/< 2 rating categories). MRI biomarkers included brain-predicted age and brain-predicted age difference (brain-PAD), central vein sign (CVS)-positive lesion percentage (CVS%), paramagnetic rim and cortical lesions, T2-lesion load, and brain volumetry. The variable relative importance for EPVS-category prediction was explored using a classification random forest approach.

RESULTS

High EPVS patients were older (49 vs 44 years, p = 0.003), had ⩾ 1 vascular risk factors (VRFs; p = 0.005), lower CVS% (67% vs 78%, p < 0.001), reduced brain volumes (whole brain: 0.63 vs 0.73, p = 0.01; gray matter: 0.36 vs 0.40; p = 0.002), and older brain-predicted age (58 vs 50 years, p < 0.001). No differences were found for neuroinflammatory markers. After adjusting for age and VFRs (multivariate analyses), the high EPVS category correlated with lower CVS% (odds ratio (OR) = 0.98, 95% confidence interval (CI) = 0.96-0.99; p = 0.02), lower whole brain (OR = 0.01, 95% CI = 0.0003-0.5; p = 0.02), gray matter (OR = 0.0004, 95% CI = 0.0000004-0.4; p = 0.03) volumes, and higher brain-PAD (OR = 1.05, 95% CI = 1.01-1.09; p = 0.02). Random forest identified brain-PAD as the most important predictor of high EPVS.

CONCLUSION

EPVS in MS likely reflect microangiopathic disease rather than neuroinflammation, potentially contributing to accelerated neurodegeneration.

Determinants and Biomarkers of Progression Independent of Relapses in Multiple Sclerosis

Clinical, pathological, and imaging evidence in multiple sclerosis (MS) suggests that a smoldering inflammatory activity is present from the earliest stages of the disease and underlies the progression of disability, which proceeds relentlessly and independently of clinical and radiological relapses (PIRA). The complex system of pathological events driving "chronic" worsening is likely linked with the early accumulation of compartmentalized inflammation within the central nervous system as well as insufficient repair phenomena and mitochondrial failure. These mechanisms are partially lesion-independent and differ from those causing clinical relapses and the formation of new focal demyelinating lesions; they lead to neuroaxonal dysfunction and death, myelin loss, glia alterations, and finally, a neuronal network dysfunction outweighing central nervous system (CNS) compensatory mechanisms. This review aims to provide an overview of the state of the art of neuropathological, immunological, and imaging knowledge about the mechanisms underlying the smoldering disease activity, focusing on possible early biomarkers and their translation into clinical practice. ANN NEUROL 2024;96:1-20.

As time goes by: Treatment challenges in elderly people with multiple sclerosis

A demographic shift in multiple sclerosis (MS) is leading to an increased number of elderly people with MS (pwMS) and a rise in late-onset MS (LOMS) cases. This shift adds complexity to the treatment management of these patients, due to enhanced treatment-associated risks and the possible interplay between immunosenescence and disease-modifying therapies (DMTs). In the present paper, we performed a systematic review of the current evidence concerning the relationship between aging and treatment management in elderly pwMS. Our literature search identified 35 original studies relevant to this topic. The gathered evidence consistently indicates a diminished efficacy of DMTs in older pwMS, particularly in preventing disability accrual. Against this background, high-efficacy therapies (HETs) appear to show less benefit over moderate-low-efficacy DMTs in older patients. These data mainly derive from observational retrospective studies or meta-analyses conducted on randomized clinical trials (RCTs). RCTs, however, exclude pwMS older than 55 years, limiting our ability to acquire robust evidence regarding this patient group. Regarding treatment discontinuation in elderly pwMS with stable disease, the available data, which mainly focuses on older injectable DMTs, suggests that their suspension appears to be relatively safe in terms of disease activity. Nevertheless, the first RCT specifically targeting treatment discontinuation recently failed to demonstrate the non-inferiority of treatment discontinuation over continuation, in terms of MRI activity. On the other hand, the evidence on the impact of discontinuation on disease progression is more conflicting and less robust. Furthermore, there is an important lack of studies concerning sequestering DMTs and virtually no data on the discontinuation of anti-CD20 monoclonal antibodies. De-escalation strategy is gaining attention as a de-risking approach alternative to complete treatment discontinuation. It may be defined as the decision to shift from HETs to less potent DMTs in elderly pwMS who have a stable disease. This strategy could reduce treatment-related risks, while minimizing the risk of disease activity and progression potentially associated with treatment discontinuation. This approach, however, remains unexplored due to a lack of studies. Given these findings, the present scenario underlines the urgent need for more comprehensive and robust studies to develop optimized, data-driven treatment strategies for elderly pwMS and LOMS, addressing the unique challenges of MS treatment and aging.

Comparative CNS Pharmacology of the Bruton's Tyrosine Kinase (BTK) Inhibitor Tolebrutinib Versus Other BTK Inhibitor Candidates for Treating Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Tolebrutinib is a covalent BTK inhibitor designed and selected for potency and CNS exposure to optimize impact on BTK-dependent signaling in CNS-resident cells. We applied a translational approach to evaluate three BTK inhibitors in Phase 3 clinical development in MS with respect to their relative potency to block BTK-dependent signaling and exposure in the CNS METHODS: We used in vitro kinase and cellular activation assays, alongside pharmacokinetic sampling of cerebrospinal fluid (CSF) in the non-human primate cynomolgus to estimate the ability of these candidates (evobrutinib, fenebrutinib, and tolebrutinib) to block BTK-dependent signaling inside the CNS.

RESULTS

In vitro kinase assays demonstrated that tolebrutinib reacted with BTK 65-times faster than evobrutinib, while fenebrutinib, a classical reversible antagonist with a Ki value of 4.7 nM and slow off-rate (1.54 x 10-5 s-1), also had an association rate 1760-fold slower (0.00245 μM-1 * s-1). Estimates of cellular potency were largely consistent with the in vitro kinase assays, with an estimated IC50 of 0.7 nM for tolebrutinib against 33.5 nM for evobrutinib and 2.9 nM for fenebrutinib. We then observed that evobrutinib, fenebrutinib, and tolebrutinib achieved similar levels of exposure in non-human primate CSF after oral doses of 10 mg/kg. However, tolebrutinib CSF exposure (4.8 ng/mL) (kp,uu CSF=0.40) exceeded the IC90 (the estimated concentration inhibiting 90% of kinase activity) value, while evobrutinib (3.2 ng/mL) (kp,uu CSF=0.13) and fenebrutinib (12.9 ng/mL) (kp,uu CSF=0.15) failed to reach the estimated IC90 values.

CONCLUSIONS

Tolebrutinib was the only candidate of the three that attained relevant CSF exposure in non-human primates.

B cell-targeting chimeric antigen receptor T cells as an emerging therapy in neuroimmunological diseases

BACKGROUND

Neuroimmunology research and development has been marked by substantial advances, particularly in the treatment of neuroimmunological diseases, such as multiple sclerosis, myasthenia gravis, neuromyelitis optica spectrum disorders, and myelin oligodendrocyte glycoprotein antibody disease. With more than 20 drugs approved for multiple sclerosis alone, treatment has become more personalised. The approval of disease-modifying therapies, particularly those targeting B cells, has highlighted the role of immunotherapeutic interventions in the management of these diseases. Despite these successes, challenges remain, particularly for patients who do not respond to conventional therapies, underscoring the need for innovative approaches.

RECENT DEVELOPMENTS

The approval of monoclonal antibodies, such as ocrelizumab and ofatumumab, which target CD20, and inebilizumab, which targets CD19, for the treatment of various neuroimmunological diseases reflects progress in the understanding and management of B-cell activity. However, the limitations of these therapies in halting disease progression or activity in patients with multiple sclerosis or neuromyelitis optica spectrum disorders have prompted the exploration of cell-based therapies, particularly chimeric antigen receptor (CAR) T cells. Initially successful in the treatment of B cell-derived malignancies, CAR T cells offer a novel therapeutic mechanism by directly targeting and eliminating B cells, potentially overcoming the shortcomings of antibody-mediated B cell depletion. WHERE NEXT?: The use of CAR T cells in autoimmune diseases and B cell-driven neuroimmunological diseases shows promise as a targeted and durable option. CAR T cells act autonomously, penetrating deep tissue and effectively depleting B cells, especially in the CNS. Although the therapeutic potential of CAR T cells is substantial, their application faces hurdles such as complex logistics and management of therapy-associated toxic effects. Ongoing and upcoming clinical trials will be crucial in determining the safety, efficacy, and applicability of CAR T cells. As research progresses, CAR T cell therapy has the potential to transform treatment for patients with neuroimmunological diseases. It could offer extended periods of remission and a new standard in the management of autoimmune and neuroimmunological disorders.

Bruton tyrosine kinase inhibitors in multiple sclerosis: evidence and expectations

PURPOSE OF REVIEW

Despite availability of high-efficacy therapies for multiple sclerosis (MS), many patients experience significant disability worsening due to limited effects of currently available drugs on central nervous system (CNS)-compartmentalized inflammation. Bruton tyrosine kinase (BTK) is an intracellular signaling molecule involved in regulation of maturation, survival, migration, and activation of B cells and microglia, which are central players in the immunopathogenesis of progressive MS. Therefore, CNS-penetrant BTK inhibitors may better prevent disease progression by targeting immune cells on both sides of the blood-brain barrier. This review gives an overview on the preliminary results of clinical trials.

RECENT FINDINGS

Currently, the efficacy and safety of six BTK inhibitors are being evaluated in clinical trials in patients with relapsing and progressive MS. Evobrutinib, tolebrutinib and fenebrutinib have shown efficacy and safety in relapsing MS in phase 2 studies, and evobrutinib and tolebrutinib in their extension studies up to 3-5 years. However, evobrutinib failed to distinguish itself from the comparator drug teriflunomide in reduction of relapse rate (primary end point) in two phase 3 studies in relapsing MS.

SUMMARY

Inhibition of BTK has emerged as a promising therapeutic approach to target the CNS-compartmentalized inflammation. Results from phase 3 clinical trials will shed light on differences in efficacy and safety of BTK inhibitors and its potential role in the future MS landscape.

Glial Activity Load on PET Reveals Persistent "Smoldering" Inflammation in MS Despite Disease-Modifying Treatment: 18 F-PBR06 Study

PURPOSE OF THE REPORT

18 F-PBR06-PET targeting 18-kDa translocator protein can detect abnormal microglial activation (MA) in multiple sclerosis (MS). The objectives of this study are to develop individualized mapping of MA using 18 F-PBR06, to determine the effect of disease-modifying treatment (DMT) efficacy on reducing MA, and to determine its clinical, radiological, and serological correlates in MS patients.

PATIENTS AND METHODS

Thirty 18 F-PBR06-PET scans were performed in 22 MS patients (mean age, 46 ± 13 years; 16 females) and 8 healthy controls (HCs). Logarithmically transformed "glial activity load on PET" scores (calculated as the sum of voxel-by-voxel z -scores ≥4), "lnGALP," were compared between MS and HC and between MS subjects on high-efficacy DMTs (H-DMT, n = 13) and those on no or lower-efficacy treatment, and correlated with clinical measures, serum biomarkers, and cortical thickness.

RESULTS

Cortical gray matter (CoGM) and white matter (WM) lnGALP scores were higher in MS versus HC (+33% and +48%, P < 0.001). In H-DMT group, CoGM and WM lnGALP scores were significantly lower than lower-efficacy treatment ( P < 0.01) but remained abnormally higher than in HC group ( P = 0.006). Within H-DMT patients, CoGM lnGALP scores correlated positively with physical disability, fatigue and serum glial fibrillary acid protein levels ( r = 0.65-0.79, all P 's < 0.05), and inversely with cortical thickness ( r = -0.66, P < 0.05).

CONCLUSIONS

High-efficacy DMTs decrease, but do not normalize, CoGM and WM MA in MS patients. Such "residual" MA in CoGM is associated with clinical disability, serum biomarkers, and cortical degeneration. Individualized mapping of translocator protein PET using 18 F-PBR06 is clinically feasible and can potentially serve as an imaging biomarker for evaluating "smoldering" inflammation in MS patients.

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.

Real-world experience of teriflunomide in relapsing multiple sclerosis: paramagnetic rim lesions may play a role

Objectives

The aims of this study were to report the effectiveness and safety of teriflunomide in Chinese patients with relapsing-remitting multiple sclerosis (RRMS) and to explore the association of paramagnetic rim lesion (PRL) burden with patient outcome in the context of teriflunomide treatment and the impact of teriflunomide on PRL burden.

Methods

This is a prospective observational study. A total of 100 RRMS patients treated with teriflunomide ≥3 months were included in analyzing drug persistence and safety. Among them, 96 patients treated ≥6 months were included in assessing drug effectiveness in aspects of no evidence of disease activity (NEDA) 3. The number and total volume of PRL were calculated in 76 patients with baseline susceptibility-weighted imaging (SWI), and their association with NEDA3 failure during teriflunomide treatment was investigated.

Results

Over a treatment period of 19.7 (3.1-51.7) months, teriflunomide reduced annualized relapse rate (ARR) from 1.1 ± 0.8 to 0.3 ± 0.5, and Expanded Disability Status Scale (EDSS) scores remained stable. At month 24, the NEDA3% and drug persistence rate were 43.8% and 65.1%, respectively. In patients with a baseline SWI, 81.6% had at least 1 PRL, and 42.1% had ≥4 PRLs. The total volume of PRL per patient was 0.3 (0.0-11.5) mL, accounting for 2.3% (0.0%-49.0%) of the total T2 lesion volume. Baseline PRL number ≥ 4 (OR = 4.24, p = 0.009), younger onset age (OR = 0.94, p = 0.039), and frequent relapses in initial 2 years of disease (OR = 13.40, p = 0.026) were associated with NEDA3 failure. The PRL number and volume were not reduced (p = 0.343 and 0.051) after teriflunomide treatment for more than 24 months. No new safety concerns were identified in this study.

Conclusion

Teriflunomide is effective in reducing ARR in Chinese patients with RRMS. Patients with less PRL burden, less frequent relapses, and relatively older age are likely to benefit more from teriflunomide, indicating that PRL might be a valuable measurement to inform clinical treatment decision.

Drugs Targeting CD20 in Multiple Sclerosis: Pharmacology, Efficacy, Safety, and Tolerability

Currently, there are four monoclonal antibodies (mAbs) that target the cluster of differentiation (CD) 20 receptor available to treat multiple sclerosis (MS): rituximab, ocrelizumab, ofatumumab, and ublituximab. B-cell depletion therapy has changed the therapeutic landscape of MS through robust efficacy on clinical manifestations and MRI lesion activity, and the currently available anti-CD20 mAb therapies for use in MS are a cornerstone of highly effective disease-modifying treatment. Ocrelizumab is currently the only therapy with regulatory approval for primary progressive MS. There are currently few data regarding the relative efficacy of these therapies, though several clinical trials are ongoing. Safety concerns applicable to this class of therapeutics relate primarily to immunogenicity and mechanism of action, and include infusion-related or injection-related reactions, development of hypogammaglobulinemia (leading to increased infection and malignancy risk), and decreased vaccine response. Exploration of alternative dose/dosing schedules might be an effective strategy for mitigating these risks. Future development of biosimilar medications might make these therapies more readily available. Although anti-CD20 mAb therapies have led to significant improvements in disease outcomes, CNS-penetrant therapies are still needed to more effectively address the compartmentalized inflammation thought to play an important role in disability progression.

A metformin add-on clinical study in multiple sclerosis to evaluate brain remyelination and neurodegeneration (MACSiMiSE-BRAIN): study protocol for a multi-center randomized placebo controlled clinical trial

Introduction

Despite advances in immunomodulatory treatments of multiple sclerosis (MS), patients with non-active progressive multiple sclerosis (PMS) continue to face a significant unmet need. Demyelination, smoldering inflammation and neurodegeneration are important drivers of disability progression that are insufficiently targeted by current treatment approaches. Promising preclinical data support repurposing of metformin for treatment of PMS. The objective of this clinical trial is to evaluate whether metformin, as add-on treatment, is superior to placebo in delaying disease progression in patients with non-active PMS.

Methods and analysis

MACSiMiSE-BRAIN is a multi-center two-arm, 1:1 randomized, triple-blind, placebo-controlled clinical trial, conducted at five sites in Belgium. Enrollment of 120 patients with non-active PMS is planned. Each participant will undergo a screening visit with assessment of baseline magnetic resonance imaging (MRI), clinical tests, questionnaires, and a safety laboratory assessment. Following randomization, participants will be assigned to either the treatment (metformin) or placebo group. Subsequently, they will undergo a 96-week follow-up period. The primary outcome is change in walking speed, as measured by the Timed 25-Foot Walk Test, from baseline to 96 weeks. Secondary outcome measures include change in neurological disability (Expanded Disability Status Score), information processing speed (Symbol Digit Modalities Test) and hand function (9-Hole Peg test). Annual brain MRI will be performed to assess evolution in brain volumetry and diffusion metrics. As patients may not progress in all domains, a composite outcome, the Overall Disability Response Score will be additionally evaluated as an exploratory outcome. Other exploratory outcomes will consist of paramagnetic rim lesions, the 2-minute walking test and health economic analyses as well as both patient- and caregiver-reported outcomes like the EQ-5D-5L, the Multiple Sclerosis Impact Scale and the Caregiver Strain Index.

Ethics and dissemination

Clinical trial authorization from regulatory agencies [Ethical Committee and Federal Agency for Medicines and Health Products (FAMHP)] was obtained after submission to the centralized European Clinical Trial Information System. The results of this clinical trial will be disseminated at scientific conferences, in peer-reviewed publications, to patient associations and the general public.

Trial registration

ClinicalTrials.gov Identifier: NCT05893225, EUCT number: 2023-503190-38-00.

Paramagnetic rim lesions and the central vein sign: Characterizing multiple sclerosis imaging markers

BACKGROUND AND PURPOSE

Paramagnetic rims and the central vein sign (CVS) are proposed imaging markers of multiple sclerosis (MS) lesions. Using 7 tesla magnetic resonance imaging, we aimed to: (1) characterize the appearance of paramagnetic rim lesions (PRLs); (2) assess whether PRLs and the CVS are associated with higher levels of MS pathology; and (3) compare the characteristics between subjects with and without PRLs in early MS.

METHODS

Prospective study of 32 treatment-naïve subjects around the time of diagnosis who were assessed for the presence of PRLs and the CVS. Comparisons of lesion volume and macromolecular pool size ratio (PSR) index, a proxy of myelin integrity, between PRLs and non-PRLs, and CVS-positive and CVS-negative lesions were carried out. Differences in clinical/demographic characteristics between patients with PRLs and those without were tested.

RESULTS

Fifteen subjects had ≥1 PRL for a total of 36 PRLs, of which two-thirds had a full rim. PRLs predicted a larger lesion size and decreased PSR signal. Lesion volume and presence of cervical spine lesions were significantly different between subjects with PRLs and those without, although neither remained significant after adjusting for multiple comparisons. One hundred and eighty-one lesions with CVS were identified with no differences between CVS-positive and CVS-negative lesions in volume (p = .27) and PSR values (p = .62).

CONCLUSIONS

PRLs, but not CVS-positive lesions, are larger and have lower myelin integrity. Our findings indicate that PRLs are associated with higher levels of lesion-specific pathology prior to the start of disease-modifying therapy.