Positron Emission Tomography with [18 F]-DPA-714 Unveils a Smoldering Component in Most Multiple Sclerosis Lesions which Drives Disease Progression.

OBJECTIVE: To determine the prognostic value of persisting neuroinflammation in multiple sclerosis (MS) lesions, we developed a 18 kDa-translocator-protein-positron emission tomography (PET) -based classification of each lesion according to innate immune cell content and localization. We assessed the respective predictive value of lesion phenotype and diffuse inflammation on atrophy and disability progression over 2 years. METHODS: Thirty-six people with MS (disease duration 9 ± 6 years; 12 with relapsing-remitting, 13 with secondary-progressive, and 11 with primary-progressive) and 19 healthy controls (HCs) underwent a dynamic [18 F]-DPA-714-PET. At baseline and after 2 years, the patients also underwent a magnetic resonance imaging (MRI) and neurological examination. Based on a threshold of significant inflammation defined by a comparison of [18 F]-DPA-714 binding between patients with MS and HCs, white matter lesions were classified as homogeneously active (active center), rim-active (inactive center and active periphery), or nonactive. Longitudinal cortical atrophy was measured using Jacobian integration. RESULTS: Patients with MS had higher innate inflammation in normal-appearing white matter (NAWM) and cortex than HCs (respective standardized effect size = 1.15, 0.89, p = 0.003 and < 0.001). Out of 1,335 non-gadolinium-enhancing lesions, 53% were classified as homogeneously-active (median = 17 per patient with MS), 6% rim-active (median = 1 per patient with MS), and 41% non-active (median = 14 per patient with MS). The number of homogenously-active lesions was the strongest predictor of longitudinal changes, associating with cortical atrophy (ß = 0.49, p = 0.023) and Expanded Disability Status Scale (EDSS) changes (ß = 0.35, p = 0.023) over 2 years. NAWM and cortical binding were not associated to volumetric and clinical changes. INTERPRETATION: The [18 F]-DPA-714-PET revealed that an unexpectedly high proportion of MS lesions have a smoldering component, which predicts atrophy and clinical progression. This suggests that following the acute phase, most lesions develop a chronic inflammatory component, promoting neurodegeneration and clinical progression. ANN NEUROL 2023;94:366-383.

Clinical and radiological correlates of apathy in multiple sclerosis.

BACKGROUND: Although apathy has been associated with fronto-striatal dysfunction in several neurological disorders, its clinical and magnetic resonance imaging (MRI) correlates have been poorly investigated in people with multiple sclerosis (PwMS). OBJECTIVES: To evaluate clinical variables and investigate microstructural integrity of fronto-striatal grey matter (GM) and white matter (WM) structures using diffusion tensor imaging (DTI). METHODS: A total of 123 PwMS (age: 40.25 ± 11.5; female: 60.9%; relapsing-remitting multiple sclerosis: 75.6%) were prospectively enrolled and underwent neurological and neuropsychological evaluation, including Expanded Disability Status Scale (EDSS), Apathy Evaluation Scale (AES-S), Hospital Anxiety and Depression Scale (HADS), Modified Fatigue Impact Scale (MFIS) and brain 3T-MRI volumes of whole brain, frontal/prefrontal cortex (PFC) and subcortical regions were calculated. DTI-derived metrics were evaluated in the same GM regions and in connecting WM tracts. RESULTS: Apathetic PwMS (32.5%) showed lower education levels, higher HADS, MFIS scores and WM lesions volume than nonapathetic PwMS. Significant differences in DTI metrics were found in middle frontal, anterior cingulate and superior frontal PFC subregions and in caudate nuclei. Significant alterations were found in the right cingulum and left striatal-frontorbital tracts. CONCLUSIONS: Apathy in PwMS is associated with higher levels of physical disability, depression, anxiety and fatigue together with lower educational backgrounds. Microstructural damage within frontal cortex, caudate and fronto-striatal WM bundles is a significant pathological substrate of apathy in multiple sclerosis (MS).

An aggressive form of MOGAD treated with aHSCT: A case report.

BACKGROUND: Although myelin-oligodendrocyte-glycoprotein (MOG)-antibody-associated disease (MOGAD) has been considered a more favorable demyelinating central nervous system disorder, recent data evidence that some patients might experience severe relapses and high disability. Actual treatment-options are acquired mostly from anti-aquaporin-4-antibody-positive neuromyelitis optica spectrum disorder and rely on clinical experience. Therefore, treatment of aggressive forms of MOGAD can be challenging. OBJECTIVES AND METHODS: To describe a patient with an aggressive MOGAD treated with autologous hematopoietic stem cell transplantation (aHSCT). RESULTS: A 56-year-old man was diagnosed with MOGAD in 2017 because of right optic-neuritis and anti-MOG-antibody positivity. In the following 2 years, he experienced two optic neuritis with good recovery after high-dose steroid. At the end of 2019, he presented sensory and motor impairment at lower limbs with evidence of several spinal, longitudinally extended, tumefactive inflammatory lesions. Despite sequential treatment with rituximab and tocilizumab alongside high-dose steroid, intravenous immunoglobulins and plasma-exchange, he experienced several clinical relapses and exhibited persistent magnetic resonance activity. He was finally addressed to intense immunosuppression with myeloablative conditioning regimen followed by autologous hematopoietic stem cell transplantation (aHSCT). After 2 years follow-up, he is free from disease-activity. CONCLUSIONS: In a patient affected by aggressive, treatment-refractory MOGAD, aHSCT resulted as safe and was able to suppress disease-activity for over 2 years.

Embracing resilience in multiple sclerosis: a new perspective from COVID-19 pandemic.

Coronavirus disease 2019 (COVID-19) resulted in several psychological consequences. Past epidemiological experiences already showed the deep albeit heterogeneous psychological repercussions of pandemics. Nevertheless, little is known about COVID-19 outbreak and the possible strategies for boosting resilience in patients with chronic diseases such as Multiple Sclerosis (MS). Therefore, we designed a study aiming to assess the changes in mental distress during COVID-19 outbreak in patients with MS and to identifyfactors contributing to resilience's development.We enrolled 106 patients (69 relapsing-remitting, 20 secondary-progressive, and 17 primary-progressive) whose neuropsychological assessment before the COVID-19 pandemic (1 January 2019-1 March 2020) was available. It consisted of Brief International Cognitive Assessment for MS (BICAMS), Hospital Anxiety and Depression Scale (HADS) and patient-reported MS Neuropsychological Screening Questionnaire (MSNQ-P). All patients were re-tested during Italian lockdown through an online survey, comprehensive of sociodemographic information, HADS self-rating Scale, MSNQ-P Questionnaire and finally Connor-Davidson Resilience self-rating Scale (CD-RISC 25), in order to evaluate resilience.No significant changes in HADS and MSNQ-P scores were detected during COVID-19 pandemic in our population. Though, pre-existing lower HADS and MSNQ-P scores but not demographic, disease- and treatment-related elements were found significantly (p < 0.0001) and independently associated with a better resilience attitude.

Autologous hematopoietic stem cell transplantation following alemtuzumab therapy in aggressive multiple sclerosis: A report of three cases.

The management of multiple sclerosis patients with persistent disease activity under alemtuzumab treatment is not established yet. Concerns have been raised on the safety of autologous haematopoietic stem cell transplantation (aHSCT) after alemtuzumab treatment because of the risk of serious infectious adverse events. We report short-term safety and efficacy data from three patients treated with aHSCT following alemtuzumab treatment. Early adverse events were consistent with expected transplant toxicities. All patients were free of disease activity at the last follow-up. Our data suggest that aHSCT can be considered as a rescue treatment strategy for MS patients with persistent disease activity during alemtuzumab treatment.

Menstrual cycle resumption and female fertility after autologous hematopoietic stem cell transplantation for multiple sclerosis.

Data on fertility after autologous hematopoietic stem cell transplantation (aHSCT) in women with multiple sclerosis (MS) are inconclusive. This study aims to report on post-aHSCT menstrual resumption in a multi-center MS-women cohort. Out of 43 women, 30 (70%) recovered menses after a mean time of 6.8 months. Older age (odds ratio (OR) = 0.5, p < 0.0001) and previous pulsed cyclophosphamide (OR = 0.44, p = 0.005) were independently associated with a reduced menstrual recovery probability. Conditioning regimens' intensity resulted not associated with post-procedure amenorrhea. Our results highlight younger age as significantly associated with menses recovery; proper fertility counseling for MS women candidated to aHSCT both prior- and post-transplantation is therefore warranted.

Prevalence of disability improvement as a potential outcome for multiple sclerosis trials.

BACKGROUND: The concept of improvement of disability recently emerged as a new target in multiple sclerosis (MS) studies since the approval of new potent drugs and for testing drugs for neuroprotection and repair. OBJECTIVE: To propose a simple estimator for assessing and comparing the prevalence of improvement over time between groups. METHODS: The prevalence of a transient condition takes into account the incidence and the duration of such condition. We propose here the application of a modified Kaplan-Meier estimator to evaluate and compare between groups the prevalence of improvement over time in a cohort of 121 patients treated with autologous hematopoietic stem cell transplantation. RESULTS: The prevalence of improvement after 5 years from transplant was 50.3% (95%CI: [38.0-63.0]) in relapsing-remitting patients and 6.5% (95%CI: [0-17.8]) in secondary-progressive patients (p < 0.001). Such a difference wouldn't be evident considering the traditional cumulative probability of improvement at 5 years (55.5% in relapsing-remitting vs 33.4% in secondary-progressive patients, p = 0.10). CONCLUSION: This study shows the relevance of a new estimator of prevalence of improvement in MS. This estimator gives simple information on whether a drug can induce a durable improvement in disability and can be considered a potential outcome for trials assessing drugs for neuroprotection or repair.

COVID-19 pandemic and mental distress in multiple sclerosis: Implications for clinical management.

BACKGROUND AND PURPOSE: In multiple sclerosis (MS), disease-related factors and dysfunctional coping might favor the development of mental distress induced by COVID-19 containment measures. Aim of this study was exploring the relationship between disability, coping strategies, daily life reorganization and neuropsychiatric symptoms in an Italian MS population during the COVID-19 lockdown, in order to identify potentially modifiable factors that could inform clinical management of mental distress in people with MS. METHODS: We explored the relationship between mental distress, disability and coping strategies in the Italian MS population under lockdown. Structural equation modeling was applied to information collected via web survey to identify modifiable factors that could account for mental distress. RESULTS: A total of 845 participants (497 with MS and 348 controls) were included in the study. The MS group had higher scores than the control group for depression (p = 0.005), but not for anxiety, emotional dyscontrol or sleep disturbances. The structural equation modeling explained 74% of the variance observed in depression score. Within the model, three latent factors were characterized from measured variables: motor disability and cognitive dysfunction contributed to disability (ß = 0.509 and ß = 0.836; p < 0.001); positive attitude and exercise contributed to active attitude (ß = 0.386 and ß = 0.297; p < 0.001); and avoidance, social support and watching television contributed to passive attitude (ß = 0.301, ß = 0.243 and ß = 0.212; p < 0.001). With regard to the relationship between latent factors and their influence on depression, disability contributed to passive attitude (ß = 0.855; p < 0.001), while both passive and active attitude significantly influenced depression (ß = 0.729 and ß = -0.456; p < 0.001). CONCLUSION: As a practical implication of our model, favoring exercise would enhance active attitude and its positive impact on mental well-being while, at the same time, reducing the negative impact of disability on depression, representing a valuable tool in facing COVID-19-related mental distress.

Relationship Between Retinal Layer Thickness and Disability Worsening in Relapsing-Remitting and Progressive Multiple Sclerosis.

BACKGROUND: Data regarding the predictive value of optical coherence tomography (OCT)-derived measures are lacking, especially in progressive multiple sclerosis (PMS). Accordingly, we aimed at investigating whether a single OCT assessment can predict a disability risk in both relapsing-remitting MS (RRMS) and PMS. METHODS: One hundred one patients with RRMS and 79 patients with PMS underwent Spectral-Domain OCT, including intraretinal layer segmentation. All patients had at least 1 Expanded Disability Status Scale (EDSS) measurement during the subsequent follow-up (FU). Differences in terms of OCT metrics and their association with FU disability were assessed by analysis of covariance and linear regression models, respectively. RESULTS: The median FU was 2 years (range 1-5.5 years). The baseline peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell + inner plexiform layer (GCIPL) were thinner in PMS compared with RRMS (P = 0.02 and P = 0.003, respectively). In the RRMS population, multivariable models showed that the GCIPL significantly correlated with FU disability (0.04 increase in the EDSS for each 1-µm decrease in the baseline GCIPL, 95% confidence interval: 0.006-0.08; P = 0.02). The baseline GCIPL was thinner in patients with RRMS with FU-EDSS >4 compared with those with FU-EDSS ≤4, and individuals in the highest baseline GCIPL tertile had a significantly lower FU-EDSS score than those in the middle and lowest tertile (P = 0.01 and P = 0.001, respectively). These findings were not confirmed in analyses restricted to patients with PMS. CONCLUSIONS: Among OCT-derived metrics, GCIPL thickness had the strongest association with short-medium term disability in patients with RRMS. The predictive value of OCT metrics in the longer term will have to be further investigated, especially in PMS.

Treatment of multiple sclerosis with rituximab: A multicentric Italian-Swiss experience.

BACKGROUND: Rituximab, an anti-CD20 monoclonal antibody leading to B lymphocyte depletion, is increasingly used as an off-label treatment option for multiple sclerosis (MS). OBJECTIVE: To investigate the effectiveness and safety of rituximab in relapsing-remitting (RR) and progressive MS. METHODS: This is a multicenter, retrospective study on consecutive MS patients treated off-label with rituximab in 22 Italian and 1 Swiss MS centers. Relapse rate, time to first relapse, Expanded Disability Status Scale (EDSS) progression, incidence of adverse events, and radiological outcomes from 2009 to 2019 were analyzed. RESULTS: A total of 355/451 enrolled subjects had at least one follow-up visit and were included in the outcome analysis. Annualized relapse rate significantly decreases after rituximab initiation versus the pre-rituximab start year in RRMS (from 0.86 to 0.09, p < .0001) and in secondary-progressive (SP) MS (from 0.34 to 0.06, p < .0001) and had a slight decrease in primary-progressive (PP) MS patients (from 0.12 to 0.07, p = 0.45). After 3 years from rituximab start, the proportion of patients with a confirmed EDSS progression was 14.6% in the RRMS group, 24.7% in the SPMS group, and 41.5% in the PPMS group. No major safety concerns arose. CONCLUSION: Consistently with other observational studies, our data show effectiveness of rituximab in reducing disease activity in patients with MS.

Degree of microstructural changes within T1-SE versus T1-GE hypointense lesions in multiple sclerosis: relevance for the definition of "black holes".

OBJECTIVES: To retrospectively evaluate the different performances of T1-SE and T1-GE sequences in detecting hypointense lesions in multiple sclerosis (MS), to quantify the degree of microstructural damage within lesions and to correlate them with patient clinical status. METHODS: Sixty clinically isolated syndrome (CIS) and MS patients underwent brain magnetic resonance imaging (MRI) on 1.5-T and 3-T scanners. We identified T2 fluid-attenuated inversion recovery hyperintense lesions with no hypointense signal on T1-SE/T1-GE (a), hypointense lesions only on T1-GE (b), and hypointense lesions on both T1-SE and T1-GE sequences (c). We compared mean lesion number (LN) and volume (LV) identified on T1-SE and T1-GE sequences, correlating them with Expanded Disability Status Scale (EDSS); fractional anisotropy (FA) and mean diffusivity (MD) values inside each lesion type were extracted and normal-appearing white matter (NAWM). RESULTS: Thirty-five patients were female. Mean age was 39.2 (± 7.8); median EDSS was 3 (± 2). There were 23 CIS, 21 relapsing-remitting (RR), and 16 progressive MS. T1-GE and T1-SE LN and LV were significantly different (p < 0.001), both correlating with EDSS. Both FA and MD metrics resulted significantly different among the three lesion groups and NAWM (p < 0.001). FA and MD values extracted from (b) and (c) showed statistically significant differences (p < 0.001), while for (a) and (b), the differences were not significant (p = 0.31 for FA and p = 0.62 for MD). CONCLUSION: T1-SE hypointense lesions demonstrated a more pronounced degree of microstructural damage. T1-weighted sequence type must be more carefully evaluated in clinical and research settings. KEY POINTS: • T1-weighted spin-echo (T1-SE) images detect chronic hypointense lesions (so called black holes) associated with more severe microstructural changes. • In the last years, three-dimensional (3D) T1-weighted gradient-echo (T1-GE) sequences are often utilized in lieu of T1-SE acquisition, more so at 3 T or higher fields. • T1-weighted sequence type must be more carefully evaluated in clinical and research settings in the definition of "black holes" in MS, in order to avoid the overestimation of the effective severe tissue damage.

Two-way crossed cerebellar diaschisis in a clinically isolated syndrome suggestive of multiple sclerosis.

The term diaschisis refers to a neural dysfunction manifesting in anatomically intact, but functionally related, brain regions distant from a primary lesion. Here we report the diaschisis phenomenon as a consequence of a first demyelinating event in the middle and superior cerebellar peduncles in both the ipsilateral cerebellar hemisphere and in the contralateral thalamus and cerebral cortex (two-way crossed cerebellar diaschisis), resulting in the simultaneous disruption of the afferent cortico-ponto-cerebellar pathway and the efferent cerebellar-thalamo-cortical pathway. The use of 18F-FDG-PET could help clarifying in vivo the distant pathophysiological effect of focal lesions in inflammatory diseases such as multiple sclerosis.

A two alternative forced choice method for assessing vibrotactile discrimination thresholds in the lower limb.

The development of an easy to implement, quantitative measure to examine vibration perception would be useful for future application in clinical settings. Vibration sense in the lower limb of younger and older adults was examined using the method of constant stimuli (MCS) and the two-alternative forced choice paradigm. The focus of this experiment was to determine an appropriate stimulation site on the lower limb (tendon versus bone) to assess vibration threshold and to determine if the left and right legs have varying thresholds. Discrimination thresholds obtained at two stimulation sites in the left and right lower limbs showed differences in vibration threshold across the two ages groups, but not across sides of the body nor between stimulation sites within each limb. Overall, the MCS can be implemented simply, reliably, and with minimal time. It can also easily be implemented with low-cost technology. Therefore, it could be a good candidate method to assess the presence of specific deep sensitivity deficits in clinical practice, particularly in populations likely to show the onset of sensory deficits.

Intense immunosuppression followed by autologous haematopoietic stem cell transplantation as a therapeutic strategy in aggressive forms of multiple sclerosis.

In the majority of relapsing multiple sclerosis patients, the disease can be quite easily controlled by already available, approved therapies. There are, however, some aggressive cases who continue to have clinical and magnetic resonance imaging (MRI) activity in spite of the treatment. These are the cases who may now receive benefit from intense immunosuppression followed by autologous haematopoietic stem cell transplantation (aHSCT). In this review, we describe the method and the rationale of aHSCT, the more recently published studies that demonstrate its efficacy in selected multiple sclerosis cases, the problems related to safety and the transplant-related mortality risk of the procedure. A description of the ideal patient who can take advantage of aHSCT is outlined and, finally, the ongoing studies which are near to completion or are close to starting are briefly reported.

A diffusion tensor magnetic resonance imaging study of paediatric patients with severe non-traumatic brain injury.

AIM: In this observational study using 3T magnetic resonance imaging (MRI) and diffusion tensor, we investigated the differential effects of pathology, stage of disease, state of consciousness, and aetiology on the modifications of supra- and infra-tentorial white matter tracts and their correlations with clinical scales in paediatric patients with severe non-traumatic brain injury. METHOD: Diffusion tensor magnetic resonance imaging (DT-MRI) was obtained from seven children with unresponsive wakefulness syndrome (UWS; five males, two females; age at event 5y; standard deviation [SD] 2y 1mo), six children in a minimally conscious state (MCS; three males, three females; age at event 5y 10mo; SD 5y), and 10 healthy children as controls(two males, eight females; age at study 10y 10mo; SD 2y 10mo). Fractional anisotropy, mean, axial, and radial diffusivities were calculated for the corpus callosum, inferior, middle (MCP), and superior cerebellar peduncles (SCP). RESULTS: DT-MRI parameters from corpus callosum and SCP differed between patients and controls. MCP abnormalities were detected in patients presenting non-traumatic composite aetiology (n=4) versus those suffering from pure anoxia (n=9). The supra-tentorial compartment was more damaged (i.e. decreased fractional anisotropy and increased diffusivities) than the infra-tentorial one. Correlations were found between DT-MRI abnormalities and Glasgow Outcome Scale scores. INTERPRETATION: In paediatric UWS/MCS, the severity of clinical disability correlates with white matter tract abnormalities.

In vivo evidence of hippocampal dentate gyrus expansion in multiple sclerosis.

Using MR-based radial mapping, we assessed morphological alterations of the hippocampal dentate gyrus (DG) in patients with relapse-onset multiple sclerosis (MS). We analyzed different stages of the disease and the association of DG alterations with hippocampal-related cognitive functions. Using high-resolution morphological imaging, hippocampal radial mapping analysis was performed in 28 relapsing-remitting (RR), 34 secondary progressive, and 26 benign MS patients and 28 healthy controls (HC). Between-groups differences of DG radial distance (from surface points to the central core of the hippocampus) and correlations with clinical, neuropsychological, and radiological measures were evaluated using surface-based mesh modeling. Compared with HC, all MS clinical phenotypes revealed a larger radial distance of the DG, which was more marked on the left side. Radial distance enlargement was more pronounced in RRMS patients compared with the other disease clinical phenotypes and was inversely correlated to disease duration. Radial distance enlargement was correlated with higher T2 lesion volume and a better cognitive performance in RRMS and with a poor cognitive performance in secondary progressive and benign MS patients. Surface expansion of the DG might represent an inflammation-induced neurogenic (reactive) process of the subgranular zone of the hippocampus primarily aimed at rescuing the functional competence of hippocampal circuitry.

Hematopoietic stem cell transplantation for multiple sclerosis.

Over the past decades, several effective disease-modifying therapies have been approved for the treatment of multiple sclerosis (MS); however, achieving long-term disease remission remains challenging, particularly for patients with aggressive forms of MS. Intense immunosuppression followed by hematopoietic stem cell transplantation (HSCT) has been increasingly explored as a treatment strategy for aggressive MS. To date, more than 1800 MS patients have undergone HSCT worldwide. In this chapter, we provide a brief overview of the HSCT procedure, with a special focus on the unique considerations for transplanting MS patients (such as fertility preservation, prior therapy washout, and posttransplant monitoring). We also discuss the main evidence of efficacy and safety of the procedure in this context, as well as present preliminary data on the impact of HSCT on cerebrospinal fluid findings, magnetic resonance imaging metrics, and novel serum biomarkers of neurodegeneration and demyelination. In addition, we provide recommendations for patient selection from international guidelines.

HSCT for stiff person syndrome and myasthenia gravis.

Recent advances in neuroimmunology have shed light on the pathogenic mechanisms underlying rare neuroimmunologic conditions such as myasthenia gravis (MG) and stiff person syndrome (SPS). Despite the rarity of these conditions, their complex manifestations and potential for irreversible disability necessitate effective therapeutic strategies. This chapter reviews the current understanding of the safety and efficacy of hematopoietic stem cell transplantation (HSCT) in MG and SPS. Several case reports and retrospective studies have demonstrated promising outcomes following HSCT in refractory MG and SPS, with significant clinical improvement and even discontinuation of chronic immunomodulatory therapy in some cases. Furthermore, HSCT may offer insights into the underlying pathophysiologic mechanisms of these conditions, particularly the role of cellular immunity. Although more research is needed to fully understand the impact of HSCT on disease pathology and outcomes, current evidence suggests that HSCT could be a valuable therapeutic option for patients with refractory MG and SPS.

Introduction to HSCT for neurologic diseases.

The use of hematopoietic stem cell transplantation (HSCT) as a treatment option for severe autoimmune diseases originated from animal studies, with promising results in human patients reported through clinical responses seen in individuals who underwent HSCT for other reasons. Currently, over 3800 HSCT procedures have been performed specifically for autoimmune disorders and the procedure has become a standard of care for conditions such as multiple sclerosis and systemic sclerosis. Despite the growing interest among the neurology community in using HSCT to treat refractory autoimmune disorders, several obstacles must still be overcome for the procedure to become widely accepted. These include increasing the safety of the procedure, determining the most effective conditioning regimen, fostering collaboration between neurology and hematology teams, and providing robust phase III study data to demonstrate the superiority of HSCT over standard immunotherapy. This Handbook aims to provide a valuable resource for all those involved in the care of patients undergoing HSCT, and we hope it will contribute to the efforts to find the correct placement of HSCT in the therapeutic strategy of the treatment of autoimmune disorders of the nervous system.

Ongoing randomized clinical trials on HSCT in multiple sclerosis.

Autologous hematopoietic stem cell transplantation (AHSCT) is emerging as a potent treatment for highly active relapsing remitting multiple sclerosis (RRMS), potentially surpassing the efficacy of traditional disease-modifying therapies (DMTs). Phase II and III randomized controlled trials (RCTs) have demonstrated AHSCT's superiority in reducing relapse rates and delaying disability progression compared to standard DMTs. Despite the evolution of treatment guidelines, questions persist regarding patient selection criteria and optimal conditioning regimens. Notably, ongoing clinical trials in the United Kingdom, the United States, Italy, and Norway aim to address these uncertainties by evaluating the safety, efficacy, and long-term outcomes of AHSCT vs. high efficacy DMTs in both DMT-experienced and treatment-naïve patients with active RRMS or aggressive multiple sclerosis (MS). These trials promise to provide valuable insights into the positioning of AHSCT within the treatment landscape of MS.