Emerging tumefactive multiple sclerosis after switching therapy from natalizumab to fingolimod

Monoclonal Antibodies: What the Diagnostic Neuroradiologist Needs to Know

Monoclonal antibodies have become increasingly popular as novel therapeutics against a variety of diseases due to their specificity, affinity, and serum stability. Due to the nearly infinite repertoire of monoclonal antibodies, their therapeutic use is rapidly expanding, revolutionizing disease course and management, and what is now considered experimental therapy may soon become approved practice. Therefore, it is important for radiologists, neuroradiologists, and neurologists to be aware of these drugs and their possible different imaging-related manifestations, including expected and adverse effects of these novel drugs. Herein, we review the most commonly used monoclonal antibody-targeted therapeutic agents, their mechanism of action, clinical applications, and major adverse events with a focus on neurologic and neurographic effects and discuss differential considerations, to assist in the diagnosis of these conditions.

Case Report: Persisting Lymphopenia During Neuropsychiatric Tumefactive Multiple Sclerosis Rebound Upon Fingolimod Withdrawal

Fingolimod (FTY) is a disease modifying therapy for relapsing remitting multiple sclerosis (RRMS) which can lead to severe lymphopenia requiring therapy discontinuation in order to avoid adverse events. However, this can result in severe disease reactivation occasionally presenting with tumefactive demyelinating lesions (TDLs). TDLs, which are thought to originate from a massive re-entry of activated lymphocytes into the central nervous system, are larger than 2 cm in diameter and may feature mass effect, perifocal edema, and gadolinium enhancement. In these cases, it can be challenging to exclude important differential diagnoses for TDLs such as progressive multifocal leukoencephalopathy (PML) or other opportunistic infections. Here, we present the case of a 26-year-old female patient who suffered a massive rebound with TDLs following FTY discontinuation with primarily neuropsychiatric symptoms despite persisting lymphopenia. Two cycles of seven plasmaphereses each were necessary to achieve remission and ocrelizumab was used for long-term stabilization.

Pharmacovigilance during treatment of multiple sclerosis: early recognition of CNS complications

An increasing number of highly effective disease-modifying therapies for people with multiple sclerosis (MS) have recently gained marketing approval. While the beneficial effects of these drugs in terms of clinical and imaging outcome measures is welcomed, these therapeutics are associated with substance-specific or group-specific adverse events that include severe and fatal complications. These adverse events comprise both infectious and non-infectious complications that can occur within, or outside of the central nervous system (CNS). Awareness and risk assessment strategies thus require interdisciplinary management, and robust clinical and paraclinical surveillance strategies. In this review, we discuss the current role of MRI in safety monitoring during pharmacovigilance of patients treated with (selective) immune suppressive therapies for MS. MRI, particularly brain MRI, has a pivotal role in the early diagnosis of CNS complications that potentially are severely debilitating and may even be lethal. Early recognition of such CNS complications may improve functional outcome and survival, and thus knowledge on MRI features of treatment-associated complications is of paramount importance to MS clinicians, but also of relevance to general neurologists and radiologists.

Case Report: A Case of Severe Clinical Deterioration in a Patient With Multiple Sclerosis

Tumefactive multiple sclerosis (MS) is a rare variant of MS that may lead to a rapidly progressive clinical deterioration requiring a multidisciplinary diagnostic workup. Our report describes the diagnostic and therapeutic approach of a rare and extremely severe course of MS. A 51-year-old man with an 8-year history of relapsing-remitting MS (RRMS) was admitted with a subacute progressive left lower limb weakness and deterioration of walking ability. After extensive investigations including repeated MRI, microbiological, serological, cerebrospinal fluid (CSF) studies, and finally brain biopsy, the diagnosis of a tumefactive MS lesion was confirmed. Despite repeated intravenous (IV) steroids as well as plasma exchanges and IV foscarnet and ganciclovir owing to low copy numbers of human herpesvirus 6 (HHV-6) DNA in polymerase chain reaction (PCR) analysis, the patient did not recover. The clinical presentation of tumefactive MS is rare and variable. Brain biopsy for histopathological workup should be considered in immunocompromised patients with rapidly progressive clinical deterioration with brain lesions of uncertain cause.

Fulminant multifocal relapse in a fingolimod-treated multiple sclerosis patient

BACKGROUND

Fingolimod is the first approved oral disease-modifying treatment for relapsing-remitting multiple sclerosis. Fingolimod targets lymphocytes, exerting a modulator effect on cell-surface sphingosine-1-phosphate receptors and thus blocking lymphocytes egression from secondary lymphoid organs. Recent reports describe fingolimod cessation being followed by severe or pseudo-tumoral relapse, but it usually does not happen on continuous long-term treatment.

CASE PRESENTATION

Here we present the case of a patient on continuous long-term fingolimod treatment who presented with fulminant atypical multifocal relapse involving over 30 new and active lesions.

CONCLUSION

This case is unique since this fulminant multifocal relapse occurred in a patient with grade 3 lymphopenia and irreproachable adherence. This observation should be known as a possible side effect of fingolimod treatment.

Fingolimod Alters Tissue Distribution and Cytokine Production of Human and Murine Innate Lymphoid Cells

Sphingosine-1 phosphate receptor 1 (S1PR1) is expressed by lymphocytes and regulates their egress from secondary lymphoid organs. Innate lymphoid cell (ILC) family has been expanded with the discovery of group 1, 2 and 3 ILCs, namely ILC1, ILC2 and ILC3. ILC3 and ILC1 have remarkable similarity to CD4+ helper T cell lineage members Th17 and Th1, respectively, which are important in the pathology of multiple sclerosis (MS). Whether human ILC subsets express S1PR1 or respond to its ligands have not been studied. In this study, we used peripheral blood/cord blood and tonsil lymphocytes as a source of human ILCs. We show that human ILCs express S1PR1 mRNA and protein and migrate toward S1P receptor ligands. Comparison of peripheral blood ILC numbers between fingolimod-receiving and treatment-free MS patients revealed that, in vivo, ILCs respond to fingolimod, an S1PR1 agonist, resulting in ILC-penia in circulation. Similarly, murine ILCs responded to fingolimod by exiting blood and accumulating in the secondary lymph nodes. Importantly, ex vivo exposure of ILC3 and ILC1 to fingolimod or SEW2871, another S1PR1 antagonist, reduced production of ILC3- and ILC1- associated cytokines GM-CSF, IL-22, IL-17, and IFN-γ, respectively. Surprisingly, despite reduced number of lamina propria-resident ILC3s in the long-term fingolimod-treated mice, ILC3-associated IL-22, IL-17A, GM-CSF and antimicrobial peptides were high in the gut compared to controls, suggesting that its long term use may not compromise mucosal barrier function. To our knowledge, this is the first study to investigate the impact of fingolimod on human ILC subsets in vivo and ex vivo, and provides insight into the impact of long term fingolimod use on ILC populations.

Regulation of lymphocyte trafficking in central nervous system autoimmunity

CD4⁺ T helper (Th) cells play a central role in orchestrating protective immunity but also in autoimmunity. Multiple Sclerosis (MS) is a human autoimmune disease of the central nervous system (CNS) characterized by the infiltration of inflammatory lymphocytes and myeloid cells into the brain and spinal cord, leading to demyelination, axonal damage, and progressive loss of motor functions. The release of T cells in the circulation and their migration in the central nervous system are key and tightly regulated processes which have been targeted to decrease CD4⁺ T cell presence in the CNS and limit disease progression. Here, we review two of these pathways and discuss how their blockade modulate different subsets of CD4⁺ T cells.

Long-term evaluation of NEDA-3 status in relapsing-remitting multiple sclerosis patients after switching from natalizumab to fingolimod

Background:

Natalizumab significantly reduces the disease activity in patients with relapsing-remitting multiple sclerosis but due to the risk of progressive multifocal leukoencephalopathy it is often discontinued. Fingolimod is seen as an alternative, but there are no long-term analyses of the efficacy of fingolimod in this setting using the no evidence of disease activity (NEDA)-3 criteria. We provide an assessment of patients who discontinued natalizumab and switched to fingolimod or other treatments by evaluating the proportion of patients who fulfil NEDA-3 criteria after prolonged follow-up periods.

Methods:

We conducted a retrospective observational study of multiple sclerosis patients, who were treated with continuous natalizumab or who had switched to fingolimod or other treatments after natalizumab discontinuation. We assessed NEDA-3 status, annual relapse rate and determined the odds ratio between disease course after treatment switch and other patient and treatment characteristics.

Results:

A total of 61 patients on continuous natalizumab treatment and 53 patients who switched from natalizumab to fingolimod or other treatments were accompanied for up to 5 years. While the proportion of natalizumab patients fulfilling NEDA-3 criteria remained stable at 90% during the entire follow-up period, the proportion of patients switching to fingolimod or other therapies dropped to 76.7% in the first year after discontinuation, and to 50% in the years thereafter. While the median Expanded Disability Status Scale remained stable and the percentage of relapsing patients did not change significantly, recurring magnetic resonance imaging activity was found in up to 42% of the patients after switching from natalizumab to other treatments. New disease activity was significantly correlated with extended treatment gap between natalizumab discontinuation and the start of a new therapy.

Discussion:

Patients remain clinically stable after discontinuing natalizumab and switching to other therapies. However, when considering NEDA-3 criteria, a considerable proportion of patients show disease reactivation. Careful monitoring and early evaluation of alternatives is necessary after switching from natalizumab to other treatments.

Tumefactive multiple sclerosis lesions associated with fingolimod treatment: Report of 5 cases

BACKGROUND AND OBJECTIVE

Fingolimod is a sphingosine 1-phosphate receptor modulator, which sequesters lymphocytes in lymph nodes and prevents them from entering the central nervous system. There have been increasing reports of severe rebounds with tumefactive demyelinatinglesions (TDLs) in patients with multiple sclerosis under fingolimod treatment, as well as following therapy discontinuation. Our objective is to review the clinico-radiological characteristics of patients with TDLs associated with fingolimod.

METHODS

Retrospective review of medical records of MS patients from our center, who were treated with fingolimod and developed TDLs. We review the literature.

RESULTS

We found 5 cases: 4 developed TDLs as rebounds after treatment cessation and 1 under treatment. The 4 rebound cases were women, with a mean age of 34.7 years (SD = 3.6) and a mean disease duration of 10.2 years (SD = 4.1). The mean duration of fingolimod treatment before discontinuation was 36.2 months (SD = 22.4) and the mean time lapse between treatment withdrawal and rebound was 9.75 weeks (SD = 7.4). The total pre-rebound lymphocyte count (cells/mm3) was 482.5 (SD = 325.7) and1017.5 (SD = 364.8) during rebound. The TDL patient under fingolimod was a 36-year-old man who had been on fingolimod for 32 months after switching from glatiramer acetate. TDLs were multiple in 2 cases and solitary in 3. Acute treatment for rebound included high dose steroids (5/5), plasma exchange (3/5) and rituximab (2/5). Treatment after fingolimod included rituximab (2/5), alemtuzumab (2/5) and glatiramer acetate (1/5).

CONCLUSIONS

Our study, along with similar reports in literature, highlights the need for close monitoring in patients who plan to switch from fingolimod to other treatments because of the risk of severe rebound. The etiopathogenic association between fingolimod and TDLs is not clear, but given the increasing reports of cases it should be taken into account for treatment selection in patients with this type of lesions.

Pediatric multiple sclerosis and fulminant disease course: Features and approaches to treatment - A case report and review of the literature

Multiple sclerosis (MS) is the autoimmune, neurodegenerative disease of the central nervous system (CNS). Typically, it affects the young adult population, however, up to 10% of the cases, it can develop in childhood. Atypical manifestations, such as the tumefactive variant (tMS) or acute disseminated encephalomyelitis (ADEM), especially coupled with fulminant disease course, are even more rare and pose a considerable differential diagnostic and therapeutic challenge. Recently, the therapeutic strategy on the use of disease modifying therapies (DMTs) in MS has shifted to the direction of a more individualized approach, that takes the personal differences heavily into account, in particular regard to the activity and prognosis of the disease. Despite this change has only been applied to adults yet, it is plausible to predict, that it will soon be applied to pediatric patients as well, particularly, as several randomized studies are under way concerning DMTs in pediatric populations. To our best knowledge, we are the first to report a successful natalizumab treatment of pediatric fulminant tMS, in case of a 13.5 years old girl. We feel that this report demonstrates the need of early and adequate treatment in such an aggressive case, because it can reverse the course of a possibly fatal disease.

Multiple sclerosis treatment with fingolimod: profile of non-cardiologic adverse events

Fingolimod was the first oral medication approved for management of multiple sclerosis and is currently used by tens of thousands patients worldwide. Fingolimod acts via the sphingosine 1-phosphate (S1P) receptor, maintaining peripheral lymphocytes entrapped in the lymph nodes. In consequence, there is a reduction in the infiltration of aggressive lymphocytes into the central nervous system. The drug is safe and effective, and its first hours of use are associated with related to S1P receptors in the heart. This side effect is well known by all doctors prescribing fingolimod. However, the drug has other potential adverse events that, although relatively rare, require awareness from the neurologist. Among these there are infections (herpes simplex, herpes zoster, Cryptococcus, Epstein-Barr virus, hepatitis, Molluscum Contagiosum, and leishmaniosis), lung and thyroid complications, refractory headaches, encephalopathy, vasculopathy, tumefactive lesions in magnetic resonance imaging and ophthalmological disorders. The present review lists the non-cardiologic adverse events that all neurologists prescribing fingolimod should be aware of.

Pattern Recognition of the Multiple Sclerosis Syndrome

During recent decades, the autoimmune disease neuromyelitis optica spectrum disorder (NMOSD), once broadly classified under the umbrella of multiple sclerosis (MS), has been extended to include autoimmune inflammatory conditions of the central nervous system (CNS), which are now diagnosable with serum serological tests. These antibody-mediated inflammatory diseases of the CNS share a clinical presentation to MS. A number of practical learning points emerge in this review, which is geared toward the pattern recognition of optic neuritis, transverse myelitis, brainstem/cerebellar and hemispheric tumefactive demyelinating lesion (TDL)-associated MS, aquaporin-4-antibody and myelin oligodendrocyte glycoprotein (MOG)-antibody NMOSD, overlap syndrome, and some yet-to-be-defined/classified demyelinating disease, all unspecifically labeled under MS syndrome. The goal of this review is to increase clinicians’ awareness of the clinical nuances of the autoimmune conditions for MS and NMSOD, and to highlight highly suggestive patterns of clinical, paraclinical or imaging presentations in order to improve differentiation. With overlay in clinical manifestations between MS and NMOSD, magnetic resonance imaging (MRI) of the brain, orbits and spinal cord, serology, and most importantly, high index of suspicion based on pattern recognition, will help lead to the final diagnosis.

S1P1 deletion differentially affects TH17 and Regulatory T cells

Sphingosine-1 phosphate receptor 1 (S1P₁) is critical for the egress of T and B cells out of lymphoid organs. Although S1P₁ agonist fingolimod is currently used for the treatment of multiple sclerosis (MS) little is known how S1P₁ signaling regulates Th17 and T_reg cell homeostasis. To study the impact of S1P₁ signaling on Th17 and T_reg cell biology, we specifically deleted S1P₁ in Th17 and T_reg cells using IL-17A^Cre and Foxp3^Cre mice, respectively. Deletion of S1P₁ in Th17 cells conferred resistance to experimental autoimmune encephalomyelitis (EAE). On the other hand, permanent deletion of S1P₁ in T_reg cells resulted in autoimmunity and acute deletion rendered mice more susceptible to EAE. Importantly, our study revealed that S1P₁ not only regulated the egress of T_reg cells out of lymphoid organs and subsequent non-lymphoid tissue distribution but also their phenotypic diversity. Most of the T_reg cells found in S1P₁-deficient mice as well as MS patients on fingolimod therapy had an activated phenotype and were more prone to apoptosis, thus converted to effector T_reg. Our results provide novel insight into the functions of S1P₁ and potential impact of long term fingolimod use on Th17 and T_reg cell biology and general health in MS patients.

Clinical and imaging correlation in patients with pathologically confirmed tumefactive demyelinating lesions

OBJECTIVES

To characterize clinical and imaging features in patients with pathologically confirmed demyelinating lesions.

METHODS

In this retrospective chart review, we analyzed clinical-radiological-pathological correlations in patients >15years old who underwent brain biopsy at our institution between 2000 and 2015 and had inflammatory demyelination on neuropathology.

RESULTS

Of 31 patients, the mean age was 42years (range 16 to 69years) and 55% were female. All but one of the biopsied lesions were considered tumefactive demyelinating lesions (TDLs) by imaging criteria, measuring >2cm on contrast-enhanced brain MRI. On clinical follow-up, the final diagnosis was a CNS malignancy in 2 patients (6.5%). In patients without malignant tumor, the TDL was solitary in 12 (41%) and multifocal in 17 (59%), with contrast enhancement in all but one case, primarily in an incomplete rim enhancement pattern (75.9%). Of 16 patients with at least 12months of clinical follow-up, 7 (43.8%) had a clinical relapse. Of patients without a prior neurologic history, relapse occurred in 2/7 (29%) in solitary TDL and 2/6 (33%) in multifocal lesions at initial presentation. Recurrent TDLs occurred in 3 patients, all with initially solitary TDLs. Stratifying by CSF analysis, 4 of 6 patients (67%) with either an elevated IgG Index or >2 oligoclonal bands suffered a clinical relapse compared to 2/8 (25%) with non-inflammatory CSF.

CONCLUSIONS

Pathologically confirmed TDLs call for careful clinical correlation, clinical follow-up and imaging surveillance. Although sometimes clinically monophasic, tumefactive demyelinating lesions carried nearly a 45% risk of near-term clinical relapse in our study, even when presenting initially as a solitary mass lesion.

Neurological safety of fingolimod: An updated review

Fingolimod (FTY) is the first oral medication approved for treatment of relapsing–remitting multiple sclerosis (RRMS). Its effectiveness and safety were confirmed in several phase III clinical trials, but proper evaluation of safety in the real patient population requires long‐term post‐marketing monitoring. Since the approval of FTY for RRMS in Japan in 2011, it has been administered to approximately 5000 MS patients, and there have been side‐effect reports from 1750 patients. Major events included infectious diseases, hepatobiliary disorders, nervous system disorders and cardiac disorders. In the present review, we focus especially on central nervous system adverse events. The topics covered are: (i) clinical utility of FTY; (ii) safety profile; (iii) post‐marketing adverse events in Japan; (iv) white matter (tumefactive) lesions; (v) rebound after FTY withdrawal; (vi) relationship between FTY and progressive multifocal leukoencephalopathy; (vii) FTY and progressive multifocal leukoencephalopathy‐related immune reconstitution inflammatory syndrome; and (viii) neuromyelitis optica and leukoencephalopathy.

[Immune reconstitution inflammatory syndrome and rebound syndrome in multiple sclerosis patients who stopped disease modification therapy: current understanding and a case report]

More and more multiple sclerosis patients have been receiving treatment with new immunomodulatory drugs. Its discontinuation because of side-effects, lack of efficacy or pregnancy has been increasing as well. This paper reviews such severe complications of natalizumab and fingolimod cessation as immune reconstitution inflammatory syndrome (IRIS) and rebound. The short history, immunopathogenesis and diagnostic criteria of IRIS in individuals with human immunodeficiency virus infection are covered. Clinical and radiological presentations as well as possible pathogenic mechanisms of IRIS in patients treated with natalizumab and fingolimod are discussed. The authors also report the case of a woman with multiple sclerosis treated with fingolimod, who experienced a severe relapse when she stopped treatment. Diagnostic criteria and prognostic factors for IRIS and rebound are needed in patients with multiple sclerosis who discontinue the new disease modification therapy.

Neurotherapeutic Strategies for Multiple Sclerosis

Multiple sclerosis (MS) is the most common disabling neurologic disease of young adults. There are now 16 US Food and Drug Administration (FDA)-approved disease-modifying therapies for MS as well as a cohort of other agents commonly used in practice when conventional therapies prove inadequate. This article discusses approved FDA therapies as well as commonly used practice-based therapies for MS, as well as those therapies that can be used in patients attempting to become pregnant, or in patients with an established pregnancy, who require concomitant treatment secondary to recalcitrant disease activity.

Unexpected exacerbations following initiation of disease-modifying drugs in neuromyelitis optica spectrum disorder: Which factor is responsible, anti-aquaporin 4 antibodies, B cells, Th1 cells, Th2 cells, Th17 cells, or others?

Some disease-modifying drugs for multiple sclerosis, which mainly act on T cells, are ineffective for neuromyelitis optica spectrum disorder and induce unexpected relapses. These include interferon beta, glatiramer acetate, fingolimod, natalizumab, and alemtuzumab. The cases reported here suggest that dimethyl fumarate, which reduces the number of Th1 and Th17 cells and induces IL-4-producing Th2 cells, is also unsuitable for neuromyelitis optica spectrum disorder, irrespective of anti-aquaporin 4 IgG serostatus. Although oral dimethyl fumarate with manageable adverse effects is easy to initiate in the early course of multiple sclerosis, special attention should be paid for atypical demyelinating cases.

Catastrophic outcome of patients with a rebound after Natalizumab treatment discontinuation

INTRODUCTION

Natalizumab (NTZ) is an effective drug for the treatment of relapsing-remitting multiple sclerosis. In some patients discontinuation is mandatory due to the risk of progressive multifocal leukoencephalopathy. However, severe clinical and radiological worsening has been described after drug cessation. Our aim was to describe the clinical and radiological features of the rebound phenomenon.

MATERIAL AND METHODS

Patients switched from NTZ to Fingolimod (FTY) who had presented a rebound after discontinuation were selected. Clinical and magnetic resonance imaging (MRI) data were collected.

RESULTS

Four JC virus positive patients were included. The mean disease duration was 9.5 years (SD: 4.12) with a mean time of 3.1 years on NTZ. All patients started FTY within 3-4 months. Neurological deterioration started in a mean time of 3.5 months (SD: 2.08) with multifocal involvement: 75% motor disturbances, 50% cognitive impairment, 25% seizures. The average worsening in Expanded Disability Status Scale [EDSS] was of 3.25 points (SD: 2.33). The MRI showed a very large increase in T2 and gadolinium-enhanced lesions (mean: 23.67, SD: 18.58). All patients received 5 days of IV methylprednisolone, one patient required plasma exchange. All the patients presented neurological deterioration with an EDSS worsening of 1.13 points (SD: 0.48). After the rebound three patients continued treatment with FTY, only one patient restarted NTZ.

CONCLUSION

Discontinuation of NTZ treatment may trigger a severe rebound with marked clinical and radiological worsening. A very careful evaluation of benefit-risk should be considered before NTZ withdrawal, and a close monitoring and a short washout period is recommended after drug withdrawal.

Observational Study of Switching from Natalizumab to Immunomodulatory Drugs

OBJECTIVE

To determine the effect of disease-modifying drugs (DMDs) on disease activity rebound in patients discontinuing natalizumab (NTZ).

METHODS

Twenty-one patients with relapsing-remitting multiple sclerosis (RRMS) treated with NTZ for ≥1 year and who switched to DMDs (glatiramer acetate [GA] or interferon) were followed up for 12 months in clinical practice. Clinical outcomes after NTZ cessation were assessed every 3 months for 1 year and MRI was performed at 12 months.

RESULTS

Twelve months after switching from NTZ to DMDs, there were no significant differences in the annualized relapse rate (ARR) compared to the days that NTZ was used (0.3 vs. 0.1; p = 0.083); and the ARR never reached similar values to those prior to NTZ use (1.61; p < 0.001). The percentage of relapse-free patients after switching from NTZ was 71.4%. These patients did not have lower disease activity before NTZ compared with those with clinical relapses (1.3 vs. 1.7; p = 0.302), but they had lower Expanded Disability Status Scale scores (3.4 vs. 5.7; p = 0.001). DMDs had beneficial effects on MRI parameters, as 10 of 16 patients (62.5%) presented no evidence of radiological activity 12 months after NTZ discontinuation.

CONCLUSIONS

Patients with RRMS and moderate disability who discontinued NTZ for safety reasons may benefit from the DMDs GA and interferon with no known risk for progressive multifocal leukoencephalopathy.

[A case of multiple sclerosis who relapsed early after fingolimod therapy introduced]

The patient was a 46-year-old woman having a history of multiple sclerosis (MS) for 14 years. She had been treated with interferon β-1b since 2001, but discontinued because of psychiatric problems in 2006. Thereafter relapses were observed 1-2 times a year, and EDSS became 2.5 to 6.5. In April 2012, relapse of MS was noticed and the patient received introduction of fingolimod (FTY) after methylprednisolone (mPSL) pulse therapy. Twenty days later, dysarthria and lower limb weakness were appeared. Brain MRI showed more than 20 several millimeter Gd enhanced lesions in periventricular white matter, juxta-cortical white matter, and cerebellum. Careful determination and observation are required upon the FTY administration into the MS with high frequency of relapse.

Fingolimod in the treatment of relapsing-remitting multiple sclerosis: long-term experience and an update on the clinical evidence

Since the approval in 2010 of fingolimod 0.5 mg (Gilenya; Novartis Pharma AG, Basel, Switzerland) in the USA as an oral therapy for relapsing forms of multiple sclerosis, long-term clinical experience with this therapy has been increasing. This review provides a summary of the cumulative dataset from clinical trials and their extensions, plus postmarketing studies that contribute to characterizing the efficacy and safety profile of fingolimod in patients with relapsing forms of multiple sclerosis. Data from the controlled, phase III, pivotal studies [FREEDOMS (FTY720 Research Evaluating Effects of Daily Oral therapy in Multiple Sclerosis), FREEDOMS II and TRANSFORMS (Trial Assessing Injectable Interferon versus FTY720 Oral in Relapsing-Remitting Multiple Sclerosis)] in relapsing-remitting multiple sclerosis have shown that fingolimod has a robust effect on clinical and magnetic resonance imaging outcomes. The respective study extensions show that effects on annualized relapse rates are sustained with continued fingolimod treatment. Consistent, significant reductions in magnetic resonance imaging lesion counts and brain volume loss have also been sustained with long-term treatment. The safety profile of fingolimod is also examined, particularly in light of its long-term use. A summary of the adverse events of interest that are associated with fingolimod treatment and associated label guidelines are also considered, which include cardiac effects following first-dose administration, infections, lymphopenia, macular edema and pregnancy. Historic hurdles to the prescription of fingolimod and how these challenges are being met are also discussed.

Clinical efficacy, safety, and tolerability of fingolimod for the treatment of relapsing-remitting multiple sclerosis

Fingolimod is a selective immunosuppressive agent approved worldwide for the treatment of relapsing-remitting multiple sclerosis (MS), a chronic and potentially disabling neurological condition. Randomized double-blind clinical trials have shown that fingolimod significantly reduces relapse rate and ameliorates a number of brain MRI measures, including cerebral atrophy, compared to both placebo and intramuscular interferon-β1a. The effect on disability progression remains controversial, since one Phase III trial showed a significant benefit of treatment while two others did not. Although fingolimod has a very convenient daily oral dosing, the possibility of serious cardiac, ocular, infectious, and other rare adverse events justified the decision of the European Medicines Agency to approve the drug as a second-line treatment for MS patients not responsive to first-line therapy, or those with rapidly evolving course. In the United States, fingolimod is instead authorized as a first-line treatment. The aim of this review is to describe and discuss the characteristics of fingolimod concerning its efficacy, safety, and tolerability in the clinical context of multiple sclerosis management.

Tumefactive multiple sclerosis lesions in two patients after cessation of fingolimod treatment

BACKGROUND

Fingolimod (FTY) is the first oral medication approved for multiple sclerosis therapy. Until now, little has been known about the effects of FTY withdrawal regarding disease activity and development of tumefactive demyelinating lesions (TDLs), as already described in patients who discontinue natalizumab.

METHODS

In this study we present the clinical and radiological findings of two patients who had a severe rebound after FTY withdrawal and compare these with patients identified by a PubMed data bank analysis using the search term 'fingolimod rebound'. In total, 10 patients, of whom three developed TDLs, are presented.

RESULTS

Patients suffering from TDLs were free of clinical and radiological signs of disease activity under FTY therapy (100% versus 57%, compared with patients without TDLs) and had rebounds after a mean of 14.6 weeks (standard deviation 11.5) [patients without TDLs 11.7 (standard deviation 3.4)].

CONCLUSION

We propose that a good therapeutic response to FTY might be predisposing for a severe rebound after withdrawal. Consequently, therapy switches should be planned carefully with a short therapy free interval.

Neuroimaging of Natalizumab Complications in Multiple Sclerosis: PML and Other Associated Entities

Natalizumab (Tysabri) is a monoclonal antibody (α4 integrin antagonist) approved for treatment of multiple sclerosis, both for patients who fail therapy with other disease modifying agents and for patients with aggressive disease. Natalizumab is highly effective, resulting in significant decreases in rates of both relapse and disability accumulation, as well as marked decrease in MRI evidence of disease activity. As such, utilization of natalizumab is increasing, and the presentation of its associated complications is increasing accordingly. This review focuses on the clinical and neuroimaging features of the major complications associated with natalizumab therapy, focusing on the rare but devastating progressive multifocal leukoencephalopathy (PML). Associated entities including PML associated immune reconstitution inflammatory syndrome (PML-IRIS) and the emerging phenomenon of rebound of MS disease activity after natalizumab discontinuation are also discussed. Early recognition of neuroimaging features associated with these processes is critical in order to facilitate prompt diagnosis, treatment, and/or modification of therapies to improve patient outcomes.

Neuro-oncology dilemma: Tumour or tumefactive demyelinating lesion

Tumefactive demyelinating lesions (TDLs) are not an uncommon manifestation of demyelinating disease but can pose diagnostic challenges in patients without a pre-existing diagnosis of multiple sclerosis (MS) as well as in known MS patients. Brain tumours can also arise in MS patients and can be seen in chronic MS patients as co-morbidities. Delayed diagnosis or unnecessary intervention or treatment will affect the ultimate prognosis of these patients. In this article, we will review some typical cases illustrating the dilemma and review the information that helps to differentiate the two conditions. The intention is not to present an extensive differential diagnosis of both entities, but to examine some typical examples when the decision arises to decide between the two. We take a somewhat different approach, by presenting the cases in "real time", allowing the readers to consider in their own minds which diagnosis they favour, discussing in detail some of the pertinent literature, then revealing later the actual diagnosis. We would urge readers to consider re-visiting their first thoughts about each case after reading the discussion, before reading the follow-up of each case. The overall objective is to highlight the real possibility of being forced to decide between these two entities in clinical practise, present a reasonable approach to help differentiate them and especially to focus on the possibility of TDLs in order to avoid unnecessary biopsy.

Peripheral blood T cell dynamics predict relapse in multiple sclerosis patients on fingolimod

Background

Fingolimod efficiently reduces multiple sclerosis (MS) relapse by inhibiting lymphocyte egress from lymph nodes through down-modulation of sphingosine 1-phosphate (S1P) receptors. We aimed to clarify the alterations in peripheral blood T cell subsets associated with MS relapse on fingolimod.

Methods/Principal Findings

Blood samples successively collected from 23 relapsing-remitting MS patients before and during fingolimod therapy (0.5 mg/day) for 12 months and 18 healthy controls (HCs) were analysed for T cell subsets by flow cytometry. In MS patients, the percentages of central memory T (CCR7⁺CD45RO⁺) cells (TCM) and naïve T (CCR7⁺CD45RO^-) cells decreased significantly, while those of effector memory T (CCR7^-CD45RA^-) and suppressor precursor T (CD28^-) cells increased in both CD4⁺T and CD8⁺T cells from 2 weeks to 12 months during fingolimod therapy. The percentages of regulatory T (CD4⁺CD25^highCD127^low) cells in CD4⁺T cells and CCR7^-CD45RA⁺T cells in CD8⁺T cells also increased significantly. Eight relapsed patients demonstrated greater percentages of CD4⁺TCM than 15 non-relapsed patients at 3 and 6 months (p=0.0051 and p=0.0088, respectively). The IL17-, IL9-, and IL4-producing CD4⁺T cell percentages were significantly higher at pre-treatment in MS patients compared with HCs (p<0.01 for all), while the IL17-producing CD4⁺T cell percentages tended to show a transient increase at 2 weeks of fingolimod therapy (p^corr=0.0834).

Conclusions

The CD4⁺TCM percentages at 2 weeks to 12 months during fingolimod therapy are related to relapse.

Overview and safety of fingolimod hydrochloride use in patients with multiple sclerosis

INTRODUCTION

Fingolimod (Gilenya®, FTY720) is an oral sphingosine-1-phosphate analogue that was approved by the FDA in 2010 for the treatment of relapsing forms of multiple sclerosis (MS). Fingolimod's mechanism of action is primarily related to lymphocyte sequestration in primary and secondary lymphoid tissues. Phase III trials demonstrated a reduction in annualized relapse rate and MRI progression in fingolimod-treated subjects compared with both placebo and IFN-β-treated subjects. Frequent adverse effects include fatigue, gastrointestinal disturbance, headache and upper respiratory tract infection. More serious, but rare, adverse events associated with fingolimod include atrioventricular block, symptomatic bradycardia, herpetic viral infections and macular edema.

AREAS COVERED

We discuss the mechanism of action, pharmacokinetics, clinical efficacy and safety profile of fingolimod in patients with relapsing MS.

EXPERT OPINION

Fingolimod is an effective treatment for relapsing MS and its oral route of administration may be preferred by some. Fingolimod is generally well tolerated but requires diligence in patient selection and monitoring. Additional information is needed regarding risk of infection, malignancy and rebound disease with long-term use of fingolimod.

Patient experience and practice trends in multiple sclerosis - clinical utility of fingolimod

Targeting sphingosine-1-phosphate pathway with orally available immune-modulatory fingolimod (Gilenya™) therapy ameliorates relapsing-remitting multiple sclerosis (RRMS) by decreasing relapse rate as shown in FREEDOMS and TRANSFORMS. Fingolimod has also been shown to be superior to interferon-beta therapy as evidenced by TRANSFORMS. Albeit multiple benefits in treatment of multiple sclerosis including high efficacy and ease of administration, potential untoward effects such as cardiotoxicity, risk of infection, and cancer exist, thus mandating careful screening and frequent monitoring of patients undergoing treatment with fingolimod. This review outlines mechanism of action, observations, side effects, and practice guidelines on use of fingolimod in treatment of RRMS.

Second-line therapy with fingolimod for relapsing-remitting multiple sclerosis in clinical practice: the effect of previous exposure to natalizumab

BACKGROUND

To evaluate efficacy and safety of fingolimod for relapsing-remitting multiple sclerosis, particularly in patients previously exposed to natalizumab.

METHOD

Prospective observational single-centre second-line cohort study.

RESULTS

Among 71 patients treated with fingolimod 0.5 mg/day for a mean duration of 21.75 ± 12.60 months, the annualized relapse rate was 0.66 (C.I. 95% 0.27-1.05) with a significant difference between 26 patients with prior natalizumab exposure (1.15; C.I. 95% 0.12-2.17) and 45 not exposed (0.38; C.I. 95% 0.18-0.57; p = 0.002). In a multivariate negative regression model, only previous exposure to natalizumab (p = 0.049) and duration of fingolimod treatment (p < 0.001) significantly correlated with the annualized relapse rate. Previous exposure to natalizumab (p = 0.028) and duration of treatment with fingolimod (p < 0.001) were confirmed by restricting the analysis to the first 12 months of treatment with fingolimod, but were no longer statistically significant by analysing only patients (n = 51) with at least 12 months of treatment with fingolimod (0.32; C.I. 95% 0.08-0.55 vs. 0.22; C.I. 95% 0.11-0.32; p = NS). No differences were observed in neuroradiological outcomes and disability progression in patients exposed to natalizumab and not exposed. The rate of discontinuation due to adverse events was 11.3%, with no differences between the two groups.

CONCLUSIONS

Our study confirms efficacy and side effects of fingolimod in a second-line clinical practice cohort. Prior natalizumab exposure and duration of treatment with fingolimod are independent predictors of annualized relapse rate during the first 12 months of treatment with fingolimod, but not in the long-term, and may be influenced by the 3 months washout period between the two drugs.

Are natalizumab and fingolimod analogous second-line options for the treatment of relapsing-remitting multiple sclerosis? A clinical practice observational study

BACKGROUND

It is unclear whether natalizumab and fingolimod have analogous efficacy for relapsing-remitting multiple sclerosis (RRMS).

OBJECTIVE

To compare the outcome of RRMS patients treated with either therapy.

METHODS

RRMS patients treated with natalizumab or fingolimod at Verona Hospital, Italy, were included. The study design was retrospective, based on prospectively collected clinical and MRI data. As efficacy outcomes, time to relapse, relapse rate, expanded disability status scale (EDSS) score change, and new T2/gadolinium-enhancing lesions on brain MRI were compared over treatment period between the two groups. Multivariate Cox and logistic regression models were used to control for potential confounders.

RESULTS

Fifty-seven subjects receiving natalizumab and 30 receiving fingolimod for a median duration of 23 (1-63) and 22 (2-35) months, respectively (p = 0.22) were included. Patients treated with natalizumab had a more active pre-treatment disease course compared to those treated with fingolimod. In multivariate analysis, the relapse risk was reduced in patients on natalizumab (Hazard Ratio = 0.33; 95% CI = 0.11-1.03; p = 0.056) compared to those on fingolimod. There was no significant difference in EDSS and MRI outcomes. No relevant unexpected adverse events occurred. One patient discontinued natalizumab for progressive multifocal leukoencephalopathy.

CONCLUSIONS

RRMS patients receiving natalizumab had higher baseline disease activity and lower relapse risk over 20 months of treatment compared to those receiving fingolimod. Head-to-head randomized clinical trials are needed.

Previous treatment influences fingolimod efficacy in relapsing-remitting multiple sclerosis: results from an observational study

OBJECTIVE

Fingolimod (FTY) is licensed as a disease-modifying treatment in highly active relapsing-remitting multiple sclerosis. The aim of the study was to evaluate the efficacy and safety of FTY in a real-life setting and to explore the possible role of clinical and MRI parameters, including previous treatment type, in predicting its efficacy.

METHODS

Clinical and MRI data was collected on 127 patients assigned to treatment with FTY in six multiple sclerosis centers in Emilia-Romagna, Italy, between August 2011 and June 2013.

RESULTS

During a mean follow-up period of 10 months (range 1-22), we observed a total of 47 relapses in 39 patients (30.7%); new T2 lesions or gadolinium-enhancing (Gd+) lesions were present at follow-up MRI in 32/71 patients (45%). Expanded disability status scale (EDSS) at the end of the follow-up period was not different when compared to the baseline EDSS. Serious adverse events occurred in three patients (2.4%). A higher proportion of patients previously treated with natalizumab showed clinical (41%) or MRI activity (54%). Previous treatment with natalizumab increased the risk of a relapse within 30 days (versus immunomodulatory drugs; OR: 4.3; p = 0.011) and at survival analysis (versus remaining patients; HR: 1.9; p = 0.046). Study limitations include a small population sample, a short observation period with variable timing of follow-up MRI and different baseline characteristics of patients previously treated with natalizumab compared to those treated with immunomodulatory drugs.

CONCLUSIONS

This study confirms the efficacy of FTY in reducing relapse rate in patients previously treated with immunomodulatory drugs, while it seems to be less effective in patients discontinuing natalizumab. Due to the short duration of follow-up it is not possible to evaluate disability progression; however, no difference was observed between the groups.

Therapeutic approaches to disease modifying therapy for multiple sclerosis in adults: an Australian and New Zealand perspective: part 3 treatment practicalities and recommendations. MS Neurology Group of the Australian and New Zealand Association of Neurologists

In this third and final part of our review of multiple sclerosis (MS) treatment we look at the practical day-to-day management issues that are likely to influence individual treatment decisions. Whilst efficacy is clearly of considerable importance, tolerability and the potential for adverse effects often play a significant role in informing individual patient decisions. Here we review the issues surrounding switching between therapies, and the evidence to assist guiding the choice of therapy to change to and when to change. We review the current level of evidence with regards to the management of women in their child-bearing years with regards to recommendations about treatment during pregnancy and whilst breast feeding. We provide a summary of recommended pre- and post-treatment monitoring for the available therapies and review the evidence with regards to the value of testing for antibodies which are known to be neutralising for some therapies. We review the occurrence of adverse events, both the more common and troublesome effects and those that are less common but have potentially much more serious outcomes. Ways of mitigating these risks and managing the more troublesome adverse effects are also reviewed. Finally, we make specific recommendations with regards to the treatment of MS. It is an exciting time in the world of MS neurology and the prospects for further advances in coming years are high.

A rare presentation of atypical demyelination: tumefactive multiple sclerosis causing Gerstmann's syndrome

Background

Tumefactive demyelinating lesions are a rare manifestation of multiple sclerosis (MS). Differential diagnosis of such space occupying lesions may not be straightforward and sometimes necessitate brain biopsy. Impaired cognition is the second most common clinical manifestation of tumefactive MS; however complex cognitive syndromes are unusual.

Case presentation

We report the case of a 30 year old woman who presented with Gerstmann’s syndrome. MRI revealed a large heterogeneous contrast enhancing lesion in the left cerebral hemisphere. Intravenous corticosteroids did not stop disease progression. A tumour or cerebral lymphoma was suspected, however brain biopsy confirmed inflammatory demyelination. Following diagnosis of tumefactive MS treatment with natalizumab effectively suppressed disease activity.

Conclusions

The case highlights the need for clinicians, radiologists and surgeons to appreciate the heterogeneous presentation of tumefactive MS. Early brain biopsy facilitates rapid diagnosis and management. Treatment with natalizumab may be useful in cases of tumefactive demyelination where additional evidence supports a diagnosis of relapsing MS.

Fingolimod after natalizumab and the risk of short-term relapse

OBJECTIVE

To determine early risk of relapse after switch from natalizumab to fingolimod; to compare the switch experience to that in patients switching from interferon-β/glatiramer acetate (IFN-β/GA) and those previously treatment naive; and to determine predictors of time to first relapse on fingolimod.

METHODS

Data were obtained from the MSBase Registry. Relapse rates (RRs) for each patient group were compared using adjusted negative binomial regression. Survival analyses coupled with adjusted Cox regression were used to model predictors of time to first relapse on fingolimod.

RESULTS

A total of 536 patients (natalizumab-fingolimod [n = 89]; IFN-β/GA-fingolimod [n = 350]; naive-fingolimod [n = 97]) were followed up for a median 10 months. In the natalizumab-fingolimod group, there was a small increase in RR on fingolimod (annualized RR [ARR] 0.38) relative to natalizumab (ARR 0.26; p = 0.002). RRs were generally low across all patient groups in the first 9 months on fingolimod (RR 0.001-0.13). However, 30% of patients with disease activity on natalizumab relapsed within the first 6 months on fingolimod. Independent predictors of time to first relapse on fingolimod were the number of relapses in the prior 6 months (hazard ratio [HR] 1.59 per relapse; p = 0.002) and a gap in treatment of 2-4 months compared to no gap (HR 2.10; p = 0.041).

CONCLUSIONS

RRs after switch to fingolimod were low in all patient groups. The strongest predictor of relapse on fingolimod was prior relapse activity. Based on our data, we recommend a maximum 2-month treatment gap for switches to fingolimod to decrease the hazard of relapse.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that RRs are not higher in patients with multiple sclerosis switching to fingolimod from natalizumab compared to those patients switching to fingolimod from other therapies.

Differential effects of fingolimod on B-cell populations in multiple sclerosis

BACKGROUND

Fingolimod is an oral drug approved for multiple sclerosis (MS) with an ability to trap central memory T cells in secondary lymphoid tissues; however, its variable effectiveness in individual patients indicates the need to evaluate its effects on other lymphoid cells.

OBJECTIVE

To clarify the effects of fingolimod on B-cell populations in patients with MS.

METHODS

We analysed blood samples from 9 fingolimod-treated and 19 control patients with MS by flow cytometry, to determine the frequencies and activation states of naive B cells, memory B cells, and plasmablasts.

RESULTS

The frequencies of each B-cell population in peripheral blood mononuclear cells (PBMC) were greatly reduced 2 weeks after starting fingolimod treatment. Detailed analysis revealed a significant reduction in activated memory B cells (CD38(int-high)), particularly those expressing Ki-67, a marker of cell proliferation. Also, we noted an increased proportion of activated plasmablasts (CD138(+)) among whole plasmablasts, in the patients treated with fingolimod.

CONCLUSIONS

The marked reduction of Ki-67(+) memory B cells may be directly linked with the effectiveness of fingolimod in treating MS. In contrast, the relative resistance of CD138(+) plasmablasts to fingolimod may be of relevance for understanding the differential effectiveness of fingolimod in individual patients.

Bridging, switching or drug holidays - how to treat a patient who stops natalizumab?

Natalizumab (NAT) was the first monoclonal antibody to be approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). While pivotal and postmarketing studies have showed considerable and sustained efficacy of NAT in RRMS, the increasing incidence of therapy-associated progressive multifocal leukoencephalopathy (PML), a brain infection caused by the John Cunningham virus (JCV), is a risk associated with long-term therapy. The risk for therapy-associated PML is highest in so-called “triple risk” patients. Therefore, long-term NAT-treated, immunosuppressive-pretreated, and JCV antibody-positive patients often discontinue NAT therapy. However, until now, it is not known which treatment strategy should be followed after NAT cessation. Since disease activity returns to pretreatment levels, or even above, within 4–7 months from the last infusion of NAT, patients who stop NAT are at considerable risk of relapse and worsening of multiple sclerosis (MS)-related disability. Several strategies have been applied to prevent the recurrence of disease activity after discontinuation of NAT. Of these, bridging with intravenous methylprednisolone, and switching to glatiramer acetate or interferon beta (IFN-beta) do not seem to be effective enough. More promising results have been obtained in retrospective studies and case series with fingolimod (FTY), an alternative escalation therapy for RRMS, although some patients have showed a severe disease rebound after starting FTY treatment. The time interval between the discontinuation of NAT and the start of FTY might affect the recurrence of disease activity. Long-term data about the efficacy and safety of FTY treatment after cessation of NAT are urgently needed and should be further investigated. Prospective studies are warranted, to optimize treatment strategies for RRMS patients who discontinue NAT, especially because new therapies will be available in the very near future.

Pseudotumoral rebound of multiple sclerosis in a pregnant patient after stopping natalizumab

Natalizumab is a highly efficacious treatment for active relapsing-remitting multiple sclerosis, dramatically reducing both clinical and radiological signs of inflammation in most patients. The disease course after stopping treatment and especially the emergence of rebound activity are still a matter of debate. We present a case of dramatic reactivation of clinical disease activity with newly emerging pseudotumoral lesions in a patient who stopped treatment due to pregnancy. Both the clinical and radiological presentation suggest a rebound and necessitate close monitoring of patients stopping their treatment during pregnancy, even after a long period of stable disease.

Defective sphingosine 1-phosphate receptor 1 (S1P1) phosphorylation exacerbates TH17-mediated autoimmune neuroinflammation

Sphingosine-1-phosphate (S1P) signaling regulates lymphocyte egress from lymphoid organs into systemic circulation. Sphingosine phosphate receptor 1 (S1P₁) agonist, FTY-720 (Gilenya™) arrests immune trafficking and prevents multiple sclerosis (MS) relapses. However, alternative mechanisms of S1P-S1P₁ signaling have been reported. Phosphoproteomic analysis of MS brain lesions revealed S1P₁ phosphorylation on S351, a residue crucial for receptor internalization. Mutant mice harboring a S1pr1 gene encoding phosphorylation-deficient receptors [S1P₁(S5A)] developed severe experimental autoimmune encephalomyelitis (EAE) due to T helper (T_H) 17-mediated autoimmunity in the peripheral immune and nervous system. S1P₁ directly activated Janus-like kinase–signal transducer and activator of transcription 3 (JAK-STAT3) pathway via interleukin 6 (IL-6). Impaired S1P₁ phosphorylation enhances T_H17 polarization and exacerbates autoimmune neuroinflammation. These mechanisms may be pathogenic in MS.

The usefulness of brain MRI at onset in the differentiation of multiple sclerosis and seropositive neuromyelitis optica spectrum disorders

BACKGROUND

Although neuromyelitis optica (NMO) is a central nervous system (CNS) autoimmune disease distinct from multiple sclerosis (MS). NMO and NMO spectrum disorder (NMOSD) sometimes show asymptomatic lesions on brain magnetic resonance imaging (MRI) at onset, and even present with symptomatic brain involvement.

OBJECTIVES

We investigated whether brain MRI at onset can be helpful for the differentiation of MS and NMOSD.

METHODS

We retrospectively analyzed initial brain MRIs, performed within three months of onset, in patients with MS (n = 51) and anti-aquaporin4-antibody-positive patients with NMOSD (n = 67).

RESULTS

NMOSD patients met the Paty (37%) and Barkhof (13%) criteria, and the criteria of the European Magnetic Imaging in MS (MAGNIMS) study group (9%), for MS. Ovoid lesions perpendicular to the lateral ventricle, isolated juxtacortical lesions in U-fibers and isolated ovoid/round cortical lesions were found only in MS patients, whereas longitudinal corticospinal tract lesions, extensive hemispheric lesions, periependymal lesions surrounding the lateral ventricle and cervicomedullary lesions were found only in NMOSD patients.

CONCLUSIONS

Our study suggests that it is difficult to differentiate MS from NMOSD by the fulfillment of the MRI criteria for MS on brain MRI at onset; however, the characteristic morphology of brain lesions is highly useful for the early differentiation of the two disorders.