Ocrelizumab and ofatumumab comparison: an Italian real-world propensity score matched study.

BACKGROUND: The management of Multiple Sclerosis (MS) has undergone transformative evolution with the introduction of high-efficacy disease-modifying therapies (DMTs), specifically anti-CD20 monoclonal antibodies, such as ocrelizumab (OCR) and ofatumumab (OFA). MATERIALS AND METHODS: This is an independent retrospective cohort study in Relapsing MS (RMS) patients followed at eight Italian MS centers who initiated treatment with OCR or OFA in the participating centers and with at least 12 months on therapy. A generalized linear regression model inverse probability of treatment weight (IPTW) PS-adjusted was performed to evaluate the relationship between annualized relapse rate (ARR) and treatment groups. No evidence of disease activity-NEDA-3 at 12-month score was also collected. Safety profile of the investigated DMTs was recorded. RESULTS: A total cohort of 396 RMS patients fulfilled the required criteria and were enrolled in the study. Out of them, 216 had a prescription of OCR and 180 of OFA. The mean follow-up was 13.2 ± 1.9 months. The estimated means for ARR did not show differences between the two groups, 0.059 for patients on OCR and 0.038 for patients on OFA (p = 0.185). The generalized regression model IPTW PS-adjusted did not reveal differences between patients on OCR and OFA (ExpBOFA 0.974, 95%CI 934-1.015, p = 0.207). NEDA-3 at 12 months was experienced by 199(92.1%) patients on OCR and 170(94.4%) patients on OFA (p = 0.368). Generally, both therapies exhibit good tolerability. CONCLUSIONS: The treatment with OCR and OFA resulted in comparable control of disease activity with good safety profile. Our results need further validation in larger multicentre studies with long-term follow-up.

NEDA-3 achievement in early highly active relapsing remitting multiple sclerosis patients treated with Ocrelizumab or Natalizumab.

BACKGROUND: in the early stages of Multiple Sclerosis (MS), initiating high-efficacy disease-modifying therapy (HE DMTs) may represent an optimal strategy for delaying neurological damage and long-term disease progression, especially in highly active MS patients (HAMS). Natalizumab (NAT) and Ocrelizumab (OCR) are recognized as HE DMTs with significant anti-inflammatory effects. This study investigates NEDA-3 achievement in treatment-naïve HAMS patients receiving NAT or OCR over three years. METHODS: we retrospectively enrolled treatment-naïve HAMS patients undergoing NAT or OCR, collecting demographic, clinical, and instrumental data before and after treatment initiation to compare with propensity score analysis disease activity, time to disability worsening, and NEDA-3 achievement. RESULTS: we recruited 281 HAMS patients with a mean age of 32.7 years (SD 10.33), treated with NAT (157) or OCR (124). After three years, the Kaplan-Meier probability of achieving NEDA-3 was 66.0 % (95 % CI: 57.3 % - 76.0 %) with OCR and 68.2 % (95 % CI: 59.9 % - 77.7 %) with NAT without significant differences between the two groups (p = 0.27) DISCUSSION AND CONCLUSION: starting HE DMT with monoclonal antibodies for HAMS could achieve NEDA-3 in a high percentage of patients without differences between NAT or OCR.

ChatGPT vs. neurologists: a cross-sectional study investigating preference, satisfaction ratings and perceived empathy in responses among people living with multiple sclerosis.

BACKGROUND: ChatGPT is an open-source natural language processing software that replies to users' queries. We conducted a cross-sectional study to assess people living with Multiple Sclerosis' (PwMS) preferences, satisfaction, and empathy toward two alternate responses to four frequently-asked questions, one authored by a group of neurologists, the other by ChatGPT. METHODS: An online form was sent through digital communication platforms. PwMS were blind to the author of each response and were asked to express their preference for each alternate response to the four questions. The overall satisfaction was assessed using a Likert scale (1-5); the Consultation and Relational Empathy scale was employed to assess perceived empathy. RESULTS: We included 1133 PwMS (age, 45.26 ± 11.50 years; females, 68.49%). ChatGPT's responses showed significantly higher empathy scores (Coeff = 1.38; 95% CI = 0.65, 2.11; p > z < 0.01), when compared with neurologists' responses. No association was found between ChatGPT' responses and mean satisfaction (Coeff = 0.03; 95% CI = - 0.01, 0.07; p = 0.157). College graduate, when compared with high school education responder, had significantly lower likelihood to prefer ChatGPT response (IRR = 0.87; 95% CI = 0.79, 0.95; p < 0.01). CONCLUSIONS: ChatGPT-authored responses provided higher empathy than neurologists. Although AI holds potential, physicians should prepare to interact with increasingly digitized patients and guide them on responsible AI use. Future development should consider tailoring AIs' responses to individual characteristics. Within the progressive digitalization of the population, ChatGPT could emerge as a helpful support in healthcare management rather than an alternative.

Reply to Wostyn, P. Targeting the Cerebrospinal Fluid Compartment in Glaucoma: Still the Dark Side of the Moon? Comment on "Passaro et al. Glaucoma as a Tauopathy-Is It the Missing Piece in the Glaucoma Puzzle? J. Clin. Med. 2023, 12, 6900".

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Ocrelizumab Alters Cytotoxic Lymphocyte Function While Reducing EBV-Specific CD8+ T-Cell Proliferation in Patients With Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: The role of B cells in the pathogenic events leading to relapsing multiple sclerosis (R-MS) has only been recently elucidated. A pivotal step in defining this role has been provided by therapeutic efficacy of anti-CD20 monoclonal antibodies. Indeed, treatment with anti-CD20 can also alter number and function of other immune cells not directly expressing CD20 on their cell surface, whose activities can contribute to unknown aspects influencing therapeutic efficacy. We examined the phenotype and function of cytotoxic lymphocytes and Epstein-Barr virus (EBV)-specific immune responses in people with R-MS before and after ocrelizumab treatment. METHODS: In this prospective study, we collected blood samples from people with R-MS (n = 41) before and 6 and 12 months after initiating ocrelizumab to assess the immune phenotype and the indirect impact on cytotoxic functions of CD8+ T and NK cells. In addition, we evaluated the specific anti-EBV proliferative responses of both CD8+ T and NK lymphocytes as surrogate markers of anti-EBV activity. RESULTS: We observed that while ocrelizumab depleted circulating B cells, it also reduced the expression of activation and migratory markers on both CD8+ T and NK cells as well as their in vitro cytotoxic activity. A comparable pattern in the modulation of immune molecules by ocrelizumab was observed in cytotoxic cells even when patients with R-MS were divided into groups based on their prior disease-modifying treatment. These effects were accompanied by a significant and selective reduction of CD8+ T-cell proliferation in response to EBV antigenic peptides. DISCUSSION: Taken together, our findings suggest that ocrelizumab-while depleting B cells-affects the cytotoxic function of CD8+ and NK cells, whose reduced cross-activity against myelin antigens might also contribute to its therapeutic efficacy during MS.

Targeting shared pathways in tauopathies and age-related macular degeneration: implications for novel therapies.

The intricate parallels in structure and function between the human retina and the central nervous system designate the retina as a prospective avenue for understanding brain-related processes. This review extensively explores the shared physiopathological mechanisms connecting age-related macular degeneration (AMD) and proteinopathies, with a specific focus on tauopathies. The pivotal involvement of oxidative stress and cellular senescence emerges as key drivers of pathogenesis in both conditions. Uncovering these shared elements not only has the potential to enhance our understanding of intricate neurodegenerative diseases but also sets the stage for pioneering therapeutic approaches in AMD.

Therapeutic choices and disease activity after 2 years of treatment with cladribine: An Italian multicenter study (CladStop).

BACKGROUND AND PURPOSE: Cladribine tablets, a purine analogue antimetabolite, offer a unique treatment regimen, involving short courses at the start of the first and second year, with no further treatment needed in years 3 and 4. However, comprehensive evidence regarding patient outcomes beyond the initial 24 months of cladribine treatment is limited. METHODS: This retrospective, multicenter study enrolled 204 patients with multiple sclerosis who had completed the 2-year course of cladribine treatment. The primary outcomes were therapeutic choices and clinical disease activity assessed by annualized relapse rate after the 2-year treatment course. RESULTS: A total of 204 patients were enrolled; most patients (75.4%) did not initiate new treatments in the 12 months postcladribine. The study found a significant reduction in annualized relapse rate at the 12-month follow-up after cladribine completion compared to the year prior to starting therapy (0.07 ± 0.25 vs. 0.82 ± 0.80, p < 0.001). Furthermore, patients with relapses during cladribine treatment were more likely to start new therapies, whereas older patients were less likely. The safety profile of cladribine was favorable, with lymphopenia being the primary registered adverse event. CONCLUSIONS: This study provides insights into therapeutic choices and disease activity following cladribine treatment. It highlights cladribine's effectiveness in reducing relapse rates and disability progression, reaffirming its favorable safety profile. Real-world data, aligned with previous reports, draw attention to ocrelizumab and natalizumab as common choices after cladribine. However, larger, prospective studies for validation and a more comprehensive understanding of cladribine's long-term impact are necessary.

Identifying definite patterns of unmet needs in patients with multiple sclerosis using unsupervised machine learning.

INTRODUCTION: People with multiple sclerosis (PwMS) exhibit a spectrum of needs that extend beyond solely disease-related determinants. Investigating unmet needs from the patient perspective may address daily difficulties and optimize care. Our aim was to identify patterns of unmet needs among PwMS and their determinants. METHODS: We conducted a cross-sectional multicentre study. Data were collected through an anonymous, self-administered online form. To cluster PwMS according to their main unmet needs, we performed agglomerative hierarchical clustering algorithm. Principal component analysis (PCA) was applied to visualize cluster distribution. Pairwise comparisons were used to evaluate demographics and clinical distribution among clusters. RESULTS: Out of 1764 mailed questionnaires, we received 690 responses. Access to primary care was the main contributor to the overall unmet need burden. Four patterns were identified: cluster C1, 'information-seekers with few unmet needs'; cluster C2, 'high unmet needs'; cluster C3, 'socially and assistance-dependent'; cluster C4, 'self-sufficient with few unmet needs'. PCA identified two main components in determining the patterns: the 'public sphere' (access to information and care) and the 'private sphere' (need for assistance and social life). Older age, lower education, longer disease duration and higher disability characterized clusters with more unmet needs in the private sphere. However, demographic and clinical factors failed in explaining the four identified patterns. CONCLUSION: Our study identified four unmet need patterns among PwMS, emphasizing the importance of personalized care. While clinical and demographic factors provide some insight, additional variables warrant further investigation to fully understand unmet needs in PwMS.

Glaucoma as a Tauopathy-Is It the Missing Piece in the Glaucoma Puzzle?

Glaucoma is a chronic neurodegenerative disorder affecting the visual system which can result in vision loss and blindness. The pathogenetic mechanisms underlying glaucomatous optic neuropathy are ultimately enigmatic, prompting ongoing investigations into its potential shared pathogenesis with other neurodegenerative neurological disorders. Tauopathies represent a subclass of neurodegenerative diseases characterized by the abnormal deposition of tau protein within the brain and consequent microtubule destabilization. The extended spectrum of tauopathies includes conditions such as frontotemporal dementias, progressive supranuclear palsy, chronic traumatic encephalopathy, and Alzheimer's disease. Notably, recent decades have witnessed emerging documentation of tau inclusion among glaucoma patients, providing substantiation that this ocular disease may similarly manifest features of tauopathies. These studies found that: (i) aggregated tau inclusions are present in the somatodendritic compartment of RGCs in glaucoma patients; (ii) the etiology of the disease may affect tau splicing, phosphorylation, oligomerization, and subcellular localization; and (iii) short interfering RNA against tau, administered intraocularly, significantly decreased retinal tau accumulation and enhanced RGC somas and axon survival, demonstrating a crucial role for tau modifications in ocular hypertension-induced neuronal injury. Here, we examine the most recent evidence surrounding the interplay between tau protein dysregulation and glaucomatous neurodegeneration. We explore the novel perspective of glaucoma as a tau-associated disorder and open avenues for cross-disciplinary collaboration and new treatment strategies.

Health related quality of life in the domain of physical activity predicts confirmed disability progression in people with relapsing remitting multiple sclerosis.

INTRODUCTION: The diagnosis of the progression phase of Multiple Sclerosis (MS) is still retrospective and based on the objectivation of clinical disability accumulation. OBJECTIVES: To assess whether the Patient Reported Outcomes Measures (PROMs) scores predict the occurrence of disease progression within three years of follow-up. METHODS: Observational prospective multicenter study. Stable Relapsing-Remitting MS (RRMS) patients were enrolled. At enrollment, patients completed the following PROMs: Beck Depression Inventory- II, The Treatment Satisfaction Questionnaire for Medications, Medical Outcomes Study Short Form 36- Item (SF36), Fatigue Severity Scale. EDSS was assessed at enrollment and three years later. The outcome measure was defined as the occurrence of confirmed disability progression (CDP) within three years of follow-up. Univariable and multivariable logistic regression models were performed to study the association between the final score of each test and the outcome. RESULTS: SF36-Physical Functioning (SF36-PF) was the only independent variable associated with the outcome. The ROC curve analysis determined a score of 77.5 at SF36-PF as the cut-off point identifying patients experiencing CDP within three years of follow-up [AUC: 0.66 (95% CI: 0.56-0.75)]. CONCLUSIONS: RRMS patients scoring higher (>77.5) at SF36-PF subscale have a higher likelihood to experience CDP within the next three years.

Viral pericarditis following ocrelizumab in a multiple sclerosis patient.

Ocrelizumab is a humanized monoclonal anti-CD20 antibody, approved for the treatment of relapsing and primary-progressive multiple sclerosis. We reported a case of pericarditis in an RRMS patient treated with ocrelizumab, who presented with chest pain, high body temperature and laboratory findings of systemic inflammation, with a favorable clinical outcome.

Previous disease-modifying treatments influence T lymphocyte kinetics in people with multiple sclerosis switching to ocrelizumab.

BACKGROUND: Recently, concern has been raised about the influence of the previous disease-modifying treatments (DMTs) on the clinical efficacy of ocrelizumab (OCR). We aimed to evaluate whether the previous DMT affects the lymphocyte subset kinetics in people with Multiple Sclerosis (MS) switching to OCR. METHODS: This is a multicenter, retrospective, real-world study on consecutive MS patients who started or switched to OCR. We grouped them by prior DMT in: (i) naïve-to-treatment (NTT), (ii) switching from fingolimod (SF) and (iii) switching from natalizumab (SN). Differences in absolute lymphocyte count and lymphocyte subset count changes, considering the period from baseline to 6 months, over all the three groups were assessed with an inverse-probability-weighted regression adjustment model. RESULTS: Mean T CD4+ cell count reduction from baseline to the six-month follow-up was more pronounced in the SN group compared to the NTT (p = 0,026). Further, patients in the SF group experienced a less pronounced CD4 T cell number decrease than both NTT and SN groups (p = 0,04 and p < 0,001, respectively). Patients in the SF group experienced an increase in CD8 T cell absolute number, whereas those in the NTT and SN groups experienced a significant decrease (p = 0,015 and p < 0,001, respectively). Patients experiencing early inflammatory activity showed a lower CD8+ cell count at baseline than stable patients (p = 0,02). CONCLUSIONS: Previous DMTs influence the lymphocyte kinetics in people with MS switching to OCR. Reassessment of these findings over a larger population may help optimize the switch.

Alemtuzumab-Related Lymphocyte Subset Dynamics and Disease Activity or Autoimmune Adverse Events: Real-World Evidence.

BACKGROUND AND OBJECTIVES: alemtuzumab is a monoclonal anti-CD52 antibody acting on B and T cells in highly active multiple sclerosis (MS). We analyzed changes in lymphocyte subsets after alemtuzumab administration in relation to disease activity and autoimmune adverse events. METHODS: lymphocyte subset counts were assessed longitudinally using linear mixed models. Subset counts at baseline and during follow-up were correlated with relapse rate, adverse events, or magnetic resonance (MRI) activity. RESULTS: we recruited 150 patients followed for a median of 2.7 years (IQR: 1.9-3.7). Total lymphocytes, CD4, CD8, and CD20 significantly decreased in all patients over 2 years (p < 0.001). Previous treatment with fingolimod increased the risk of disease activity and adverse events (p = 0.029). We found a higher probability of disease reactivation in males and in patients with over three active lesions at baseline. Higher EDSS scores at baseline and longer disease duration predicted the switch to other treatments after alemtuzumab. DISCUSSION AND CONCLUSIONS: Our real-world study supports data from clinical trials in which lymphocyte subsets were not useful for predicting disease activity or autoimmune disease during treatment. The early use of an induction therapy such as alemtuzumab in patients with a lower EDSS score and short history of disease could mitigate the risk of treatment failure.

Sexual Dysfunction in People with Multiple Sclerosis: The Role of Disease Severity, Illness Perception, and Depression.

Despite being a common issue in people with multiple sclerosis (pwMS), sexual dysfunction is still underinvestigated. This work aims to assess the potential determinants of sexual dysfunction in pwMS by considering its relationship with disease severity (in terms of global disability), illness perception, and depressive symptoms. In this multicenter study, 1010 pwMS responded to an online survey. A serial mediation model considering negative illness perception and depressive symptoms as mediators of the relationship between disease severity and sexual dysfunction was conducted using the SPSS PROCESS Macro with bias-corrected bootstrapping (5000 samples). Disease severity exerts an indirect effect on sexual dysfunction via illness perception, both independently and through depressive symptoms. However, the results indicated that illness perception plays a more crucial role in sexual dysfunction in pwMS with mild disability than in pwMS with moderate-severe disability. This study suggests that higher disability increases its magnitude by enhancing negative illness perception, that, in turn, affects sexual dysfunction both directly and through depressive symptoms, especially in pwMS with mild disability. Modulating the effect of illness perception by favoring adaptive coping strategies might represent a valid approach to mitigate sexual dysfunction symptoms in MS.

Clinically Manifest Infections Do Not Increase the Relapse Risk in People with Multiple Sclerosis Treated with Disease-Modifying Therapies: A Prospective Study.

BACKGROUND: Many factors are believed to be positively associated with the incidence of relapses in people with multiple sclerosis (MS), including infections. However, their role is still controversial. We aimed to investigate whether symptomatic infections in people with MS increase the risk of relapse in the short, medium, or long term. MATERIALS AND METHODS: We enrolled consecutive patients with relapsing MS (RMS) from October to December 2018. From enrolment up to September 2020, an online questionnaire investigating the occurrence of infections was sent via WhatsApp® monthly to the enrolled patients, while in-person visits were performed every six months. When patients complained of symptoms compatible with relapses, they attended an extra in-person visit. RESULTS: We enrolled 155 patients with RMS, and 88.38% of patients were treated with disease-modifying therapies. In the dataset, 126,381 total patient days, 78 relapses, and 1202 infections were recorded over a period of about 2 years. No increased risk of relapse after clinically manifest infections was found in the short-, medium-, or long-term period. No correlation was found between all infections and the number of relapses (p = 0.212). The main analyses were repeated considering only those infections that had at least two of the following characteristics: duration of infection ≥ 4 days, body temperature > 37° Celsius, and the use of drugs (antibiotics and/or antivirals), and no significant associations were observed. CONCLUSIONS: No associations between infections and relapses were observed, likely suggesting that disease-modifying therapies may protect against the risk of relapse potentially triggered by infections.

MRI and steroid-responsive encephalopathy associated with autoimmune thyroiditis: first report of conus medullaris involvement and literature review of the known neuroimaging profiles.

BACKGROUND: Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) is a rare but potentially reversible autoimmune encephalopathy. The most frequent neuroimaging correlates are normal brain MRI or non-specific white matter hyperintensities. METHODS: We present the first description of conus medullaris involvement, also providing an extensive review of MRI patterns described so far. RESULTS: Our results show that in less than 30% of cases, it is possible to find focal SREAT neuroanatomical correlates. Among these, T2w/FLAIR temporal hyperintensities are the most frequent, followed by basal ganglia/thalamic and brainstem involvement, respectively. CONCLUSIONS: Unfortunately, spinal cord investigation is an uncommon practice in the diagnostic approach of encephalopathies, thus neglecting potential pathological lesions of the medulla spinalis. In our opinion, the extension of the MRI study to the cervical, thoracic, and lumbosacral regions may allow finding new, and hopefully specific, anatomical correlates.

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

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

Association of vitamin D serum levels and vitamin D supplementation with B cell kinetics and disease activity in Multiple Sclerosis patients treated with ocrelizumab: an Italian multi-center study.

BACKGROUND: Several observational studies have shown an association between low circulating levels of 25-hydroxy- vitamin D (25(OH)D) and an increase in inflammatory activity in Multiple Sclerosis (MS). Among its immunomodulatory functions, 25(OH)D suppresses proliferation and immunoglobulin production of B cells. 25(OH)D supplementation has been associated with better radiological outcomes in MS patients treated with interferon (IFN)-B, glatiramer acetate, fingolimod, natalizumab and rituximab. Our study is aimed at analyzing the association of 25(OH)D serum levels and supplementation with B cell kinetics and clinical-radiological outcomes of people with MS treated with ocrelizumab. METHODS: We have retrospectively collected clinical and radiological data from 136 MS patients who have been treated with ocrelizumab, have undergone at least two treatment cycles and for whom data on serum 25(OH)D levels and intake were available. The patients were divided into three groups according to baseline 25(OH)D serum levels: deficient (≤19,9 ng/ml), insufficient (20-29,9 ng/ml), and normal range 25(OH)D (>30 ng/ml). According to 25(OH)D intake, we divided our population into users and non-users. To explore B cell kinetics at six- and twelve-month follow-ups, the patients were divided into two groups: with fast repopulation (FR) and slow repopulation rate (SR), based on the reappearance or non- appearance of CD19 at each time point. RESULTS: When considering the entire population, the mean 25(OH)D serum level (sd) was 26.27 ng/ml (14.15). 43 (31,62%) patients were classified as deficient, 52 (38,24%) were classified as insufficient, and 41 (30,14%) showed 25(OH)D serum levels within the normal range. 60.29% (82/136) of the patients were classified as users, and 39.70% (54/136) as non-users. Over the eighteen-month treatment period, we observed a significant difference between the 25(OH)D users and the non-users as concerns the number of scans with at least one new/enlarging T2 lesion (2% vs 15.38%, respectively; p= 0.025). In the multinomial regression model, 25(OH)D deficiency (serum levels ≤19,9 ng/ml) was significantly associated with a higher likelihood of disease activity during a follow-up of eighteen months (p = 0.029, RRR = 4.84, Confidence Interval (CI) 1.17 - 20.01). After six months, there were 30/136 FR patients (22,05%), whereas only 22/136 (16,17%) showed early B cell reappearance at twelve month follow up. 86.66% of the patients in the FR group showed 25(OH)D levels lower than 30 ng/ml (25(OH)D deficiency or insufficiency), whereas only 65.09% of the SR patients presented vitamin D levels lower than 30 ng/ml (p= 0.024). In the logistic regression model, 25(OH)D serum levels below 30 ng/ml were associated with a higher likelihood of early B cell reappearance at six month follow up (p= 0.042). CONCLUSIONS: 25(OH)D supplementation and serum levels might be associated with B cell kinetics and radiological activity of patients with MS treated with ocrelizumab.

Disease Reactivation in Secondary Progressive Multiple Sclerosis Patients Switching from Fingolimod to Siponimod: A Case Series.

Siponimod, a selective modulator of sphingosine 1-phosphate receptors 1 (S1P1) and 5 (S1P5), has recently been marketed for patients with Secondary Progressive Multiple Sclerosis (SPMS). Herein, we report three SPMS patients presenting disease reactivation in the first three months after switching from fingolimod to siponimod. Fingolimod binds to S1P1, S1P3, S1P4 and S1P5 receptors. S1P3 holds a central role in eliciting central proinflammatory responses, thus it has been hypothesized that upregulation of S1P3 may be the mechanism behind relapses after switching from fingolimod to siponimod. Further studies are needed to investigate the safety and efficacy of this treatment sequencing.