Efficacy and safety of rituximab in multiple sclerosis and neuromyelitis optica spectrum disorder.

In Thailand, resource limitations lead many multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) patients to use off-label immunosuppressants. This study assesses the efficacy and safety of rituximab (RTX) with a CD19-based reinfusion regimen among Thai MS and NMOSD patients. A retrospective review of patients at the Faculty of Medicine Siriraj Hospital from January 1994 to April 2023 was conducted. The primary outcome assessed was the change in annualized relapse rate (ARR) for patients using RTX for over a year. Secondary outcomes included changes in the Expanded Disability Status Scale (EDSS) scores, time to the first relapse after RTX initiation for patients using RTX for over a year, and an evaluation of the safety of RTX. The study encompassed 36 MS and 39 NMOSD patients. A majority of patients (91.7% of MS and 79.5% of NMOSD) experienced no relapses during a median follow-up of 30 months (Interquartile range [IQR] 20-46) and 31 months (IQR 23-41), respectively. The median ARR significantly decreased in both MS (from 0.77 [IQR 0.42-1.83] to 0 [IQR 0-0], p < 0.001) and NMOSD (from 0.92 [IQR 0.68-1.78] to 0 [IQR 0-0.17], p < 0.001) patients after switching to RTX, with no difference between those following a fixed 6-month time point regimen and a CD19-based reinfusion regimen. Median EDSS scores improved significantly at the last follow-up visit in both groups. The mean time to the first subsequent relapse was 8.3 ± 3.0 months in MS and 6.8 ± 1.7 months in NMOSD. Mild adverse drug reactions occurred in 44% of patients. RTX effectively prevents relapses in Thai MS and NMOSD patients, with no observed serious adverse drug reactions.

The critical role of magnetic resonance imaging in the diagnosis of transverse myelitis: a case report.

INTRODUCTION: Transverse Myelitis is a rare inflammatory disorder of the spinal cord, characterized by the inflammation of the myelin sheath covering nerve fibers. Although rare, Transverse Myelitis holds significant clinical importance due to its potential life-altering consequences. The case report provides insight into the clinical presentation of Transverse Myelitis and the importance of Magnetic Resonance Imaging in confirming Transverse Myelitis. CASE PRESENTATION: A 27-year-old Nigerian female presented to a hospital facility after 2 months onset of paraplegia, urinary, and fecal incontinence. She was diagnosed with Acute Transverse Myelitis with Magnetic Resonance Imaging, a lacking imaging modality in Nigeria. On presentation, it was important to rule out spinal cord compression, a close differential to her presentation. Despite her late arrival at the facility, early diagnosis and prompt initiation of treatment with high-dose intravenous steroids and physiotherapy improved her quality of life. DISCUSSION: This case report reveals the poor health-seeking behavior in developing countries and the need for imaging modalities like Magnetic Resonance Imaging for improved diagnoses of rare neurological conditions such as Transverse Myelitis. The lack of healthcare infrastructure has led to clinical misdiagnosis, patient mismanagement, and underrepresentation of data in the country, underscoring the critical role of diagnostic tools for improved patient care pre-treatment and post-treatment. Additionally, follow-up of these patients is important to prevent the long-term sequelae of Transverse Myelitis like Neuromyelitis Optica or Multiple Sclerosis.

Different clinical phenotypes of AQP4-IgG positive NMOSD in two first degree relatives.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) are autoimmune inflammatory disorders of the CNS in which patients have severe relapses of optic neuritis and myelitis. Aquaporin-4 antibody (AQP4-IgG) positive NMOSD has not been reported in members of the same family in Sub Saharan Africa. We report the uncommon scenario in which both a Ugandan HIV positive woman and her HIV negative daughter were diagnosed with AQP4-IgG positive NMOSD. We discuss pathogenic mechanisms that may underlie familial presentation of AQP4-IgG positive NMOSD. CASE PRESENTATION: Case 1, a 54-year-old female teacher with a 20-year history of HIV infection and virally suppressed on Tenofovir, Lamivudine and Dolutegravir HAART regimen, presented with 8 months of progressive quadriparesis and urinary incontinence with a T6 sensory level. She had gadolinium enhancing longitudinally extensive transverse myelitis on MRI and was AQP4-IgG positive on serum studies. She received IV Methylprednisone 1 g daily for 3 days as a pulse and was continued on tapering doses of oral Prednisone with maintenance doses of Azathioprine. She showed slow improvements in limb motor function. Her daughter, case 2, is a 35-year-old HIV negative nutritionist, independently ambulant, with no known comorbidities or precedent autoimmune disease. She presented 1 year before her mother's AQP4-IgG positive NMOSD diagnosis with 7 months history of bilateral visual loss of rapid onset, with gadolinium-enhancing optic nerves on Brain and orbit MRI, in keeping with bilateral optic neuritis. She was AQP4-IgG positive on serum studies. She stabilized on tapered doses of oral Prednisone and continues daily oral Azathioprine with moderate improvement in her vision and no further relapses as yet. CONCLUSIONS: We add to existing literature and hypothesize that NMOSD appears to show a complex genetic background. To our knowledge, this is the first report in Sub-Saharan Africa, of familial AQP4-IgG positive NMOSD presenting with clinical heterogeneity between first degree relatives. A better understanding of the pathogenic mechanisms involved, including genome wide studies for particular risk loci for familial NMOSD, will be pivotal for future preventative and therapeutic strategies.

Non-alcoholic Wernicke's Encephalopathy mimicking neuromyelitis optica spectrum disorder in a young woman: a case report and literature review.

Wernicke's encephalopathy is an under-recognized life-threatening disease caused by thiamine (vitamin B1) deficiency. It has historically been related to chronic alcoholic intake but other causes of malnutrition, such as invasive gastric surgery and hyperemesis, have been linked to the onset of this illness over the years, often presenting with atypical clinical manifestations.  Herein we report a case of a young obese woman affected by non-alcoholic Wernicke's Encephalopathy following a minimally invasive gastrointestinal surgery. She showed an unusual clinical profile characterized by prominent subacute neuro-ophthalmological involvement which combined to her juvenile age, overweight condition and brain lesions, have made diagnosis challenging due to similarities with Neuromyelitis Optica Spectrum Disorder.   Our case underscores the relevance of prompt diagnosis in order to prevent the development of irreversible neuropathological changes and to avoid the use of a long-term immunosuppressive treatment.

Case Report: Severe rebound after withdrawal of fingolimod in a patient with neuromyelitis optica spectrum disorder.

Purpose: Fingolimod, an oral treatment for relapsing-remitting multiple sclerosis (RRMS), has been associated with a significant rebound in disease activity after therapy cessation. We described a patient with neuromyelitis optica spectrum disorder (NMOSD) who was previously diagnosed with RRMS and experienced fatal rebound syndrome after cessation of fingolimod. Case report: A 54-year-old woman, previously diagnosed with RRMS, experienced relapse after orthopedic surgery. The diagnosis was later revised to NMOSD based on a positive aquaporin-4 antibody. Three weeks after converting the immunomodulator from fingolimod to azathioprine, severe disease reactivation was observed. Considering the multiple new and enlarging magnetic resonance imaging lesions, the temporal relationship between fingolimod cessation and symptom onset, and the relatively low possibility of disease reactivation within a short time, the diagnosis of fingolimod withdrawal syndrome was proposed. Although immediate steroid pulse therapy and plasma exchange were performed, the patient eventually died owing to a fulminant clinical course. Conclusion: Fingolimod withdrawal syndrome is well known in patients with multiple sclerosis (MS). It can also occur in patients with NMOSD. Recognizing patients with NMOSD who present with MS-like manifestations, and avoiding drugs that may be harmful to patients with NMOSD, are important.

ACT001 Relieves NMOSD Symptoms by Reducing Astrocyte Damage with an Autoimmune Antibody.

Neuromyelitis optica spectrum disorder (NMOSD) is a central nervous system inflammatory demyelinating disease, the pathogenesis of which involves autoantibodies targeting the extracellular epitopes of aquaporin-4 on astrocytes. We neutralized the AQP4-IgG from NMOSD patient sera using synthesized AQP4 extracellular epitope peptides and found that the severe cytotoxicity produced by aquaporin-4 immunoglobin (AQP4-IgG) could be blocked by AQP4 extracellular mimotope peptides of Loop A and Loop C in astrocyte protection and animal models. ACT001, a natural compound derivative, has shown anti-tumor activity in various cancers. In our study, the central nervous system anti-inflammatory effect of ACT001 was investigated. The results demonstrated the superior astrocyte protection activity of ACT001 at 10 µM. Furthermore, ACT001 decreases the behavioral score in the mouse NMOSD model, which was not inferior to Methylprednisolone Sodium Succinate, the first-line therapy of NMOSD in clinical practice. In summary, our study showed that astrocytes are protected by specific peptides, or small molecular drugs, which is a new strategy for the treatment of NMOSD. It is possible for ACT001 to be a promising therapy for NMOSD.

Conus medullaris syndrome as a presenting feature of MOG-associated disease.

We report a case of conus medullaris syndrome presenting with lower limb and bladder symptoms. MR imaging showed an abnormality in the lowest part of the spinal cord as a first presentation of myelin oligodendrocyte glycoprotein (MOG)-associated disease. While such cord swelling can mimic a tumour, these patients respond well to corticosteroids, with good outcomes. MOG-associated disease is an immune-mediated syndrome distinct from aquaporin 4 antibody positive neuromyelitis optica syndrome and is now considered an independent entity. Although there can be overlapping phenotypes, there are also differences, and MOG-associated disease generally has a much better prognosis compared with aquaporin 4 antibody-positive neuromyelitis optica syndrome.

Clinical and epidemiological correlates of treatment change in patients with NMOSD: insights from the CIRCLES cohort.

OBJECTIVE: Neuromyelitis optica spectrum disorders (NMOSD) represent rare autoimmune diseases of the central nervous system largely targeting optic nerve(s) and spinal cord. The present analysis used real-world data to identify clinical and epidemiological correlates of treatment change in patients with NMOSD. METHODS: CIRCLES is a longitudinal, observational study of NMOSD conducted at 15 centers across North America. Patients with ≥ 60 days of follow-up and receiving on-study maintenance treatment were evaluated. The mean annual relapse rate (ARR) was estimated using negative binomial models; the likelihood of treatment change was estimated using Cox proportional hazards models. Relapses were included as time-varying covariates to estimate the relationship to treatment change. RESULTS: Of 542 patients included, 171 (31.5%) experienced ≥ 1 relapse on the study and 133 patients (24.5%) had ≥ 1 change in the treatment regimen. Two categories of variables significantly correlated with the likelihood of treatment change: (1) relapse: any on-study relapse (hazard ratio [HR] = 2.91; p < 0.001), relapse phenotypes (HR range = 2.15-5.49; p < 0.001), and pre-study ARR > 0.75 (HR 2.28; p < 0.001); 2) disease phenotype: brain syndrome only vs transverse myelitis involvement at onset (HR 2.44; p = 0.008), disease duration < 1 vs > 5 years (HR 1.66; p = 0.028), or autoimmune comorbidity (HR 1.55; p = 0.015). A subset of these factors significantly correlated with shorter time to first rituximab discontinuation. CONCLUSIONS: In CIRCLES, relapse patterns and disease phenotype significantly correlated with changes in the maintenance treatment regimen. Such findings may facilitate the identification of patients with NMOSD who are likely to benefit from treatment change to reduce relapse risk or disease burden and enhance the quality of life.

Remyelination in neuromyelitis optica spectrum disorder is promoted by edaravone through mTORC1 signaling activation.

Neuromyelitis optica spectrum disorder (NMOSD) is a severe inflammatory autoimmune disease of the central nervous system that is manifested as secondary myelin loss. Oligodendrocyte progenitor cells (OPCs) are the principal source of myelinating oligodendrocytes (OLs) and are abundant in demyelinated regions of NMOSD patients, thus possibly representing a cellular target for pharmacological intervention. To explore the therapeutic compounds that enhance myelination due to endogenous OPCs, we screened the candidate drugs in mouse neural progenitor cell (NPC)-derived OPCs. We identified drug edaravone, which is approved by the Food and Drug Administration (FDA), as a promoter of OPC differentiation into mature OLs. Edaravone enhanced remyelination in organotypic slice cultures and in mice, even when edaravone was administered following NMO-IgG-induced demyelination, and ameliorated motor impairment in a systemic mouse model of NMOSD. The results of mechanistic studies in NMO-IgG-treated mice and the biopsy samples of the brain tissues of NMOSD patients indicated that the mTORC1 signaling pathway was significantly inhibited, and edaravone promoted OPC maturation and remyelination by activating mTORC1 signaling. Furthermore, pharmacological activation of mTORC1 signaling significantly enhanced myelin regeneration in NMOSD. Thus, edaravone is a potential therapeutic agent that promotes lesion repair in NMOSD patients by enhancing OPC maturation.

A Novel approach using O-CVP to treat paraneoplastic NMO spectrum disorder associated with follicular lymphoma.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune neuroinflammatory disorder of the central nervous system that very rarely may be a paraneoplastic phenomenon. We describe the case of a woman with a longitudinally extensive transverse myelitis (LETM). We identified a previously undiagnosed, follicular lymphoma and she was treated with the immunochemotherapy regime (obinutuzumab, cyclophosphamide, vincristine and prednisolone; O-CVP) for paraneoplastic NMOSD. Following two cycles, there was almost complete radiological remission of the myelitis and the patient showed some improvement in her neurological function. This case illustrates the heterogeneous aetiology that LETM may have and that O-CVP may be used as therapeutic option in patients with NMOSD driven by follicular lymphoma.

Intravenous ofatumumab treatment of multiple sclerosis and related disorders: An observational study.

BACKGROUND: Ofatumumab is an anti-CD20 monoclonal antibody approved for subcutaneous administration for the treatment of relapsing multiple sclerosis (MS), but intravenously administered ofatumumab has been investigated in a phase 2 trial and used off-label. The objective of the present study was to assess disease activity and side effects in relation to longer-term intravenous ofatumumab treatment of MS and related disorders. METHODS: We conducted a retrospective study of patients treated off-label with intravenous ofatumumab for MS, neuromyelitis optica spectrum disease (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) at the Danish Multiple Sclerosis Center. Data was retrieved from the Danish Multiple Sclerosis Registry and through medical chart review. RESULTS: Fifty patients were identified with a median treatment duration of 2.2 years. Annualized relapse rate decreased from 1.03 at baseline to 0.38 during ofatumumab treatment. At 24 months, the probability of having experienced a relapse was 55% and confirmed disability worsening 7%. Frequency of infusion-related reactions was 86% during the first infusion and 42% during the last infusion. Six experienced infections requiring hospitalization. CONCLUSION: Our data indicate a reduction of relapse frequency, stabilization of disability worsening and an acceptable safety profile, although we observed a higher frequency of infusion reactions compared to data from other intravenously administered anti-CD20 monoclonal antibodies. The study supports a class effect of anti-CD20 monoclonal antibodies and the hypothesis that complement activation may be associated to a higher frequency of infusion related reactions.

Neuromyelitis Optica Spectrum Disorders in North Indian Population: Experience from a Tertiary Care Center.

Introduction: To understand neuromyelitis optica spectrum disorders (NMOSDs) better we need to study them in different populations. This prospective study was conducted to characterize clinical, serological, radiological, and therapeutic profile of NMOSDs in a North Indian population. Materials and Methods: This study included 81 patients with NMOSDs. All patients underwent detailed history and examinations and were followed at 3 monthly intervals. They were evaluated using standard investigations including gadolinium-enhanced magnetic resonance imaging (MRI) of the brain and spine with thin section optic nerve cuts and treated as per the standard guidelines. Data were recorded meticulously. Results: The mean age was 33.7 ± 13.4 years. The mean age at disease onset was 31.2 ± 13.5 years. Female-to-male ratio was 1.9:1. About 32.1% of patients presented with optic neuritis (ON), 56.8% with transverse myelitis (TM), and 11.1% with both ON and TM. The mean time from disease onset to diagnosis was 16.17 ± 23.09 months. Muscle atrophy, Lhermitte symptom, and tonic spasms were common. Foster-Kennedy syndrome-like presentation was seen in 8.6%. NMO antibodies were positive in 41 patients. MRI revealed involvement of <4 vertebral segments in 16.4% of patients with TM. Patients were managed as per standard guidelines. The mean follow-up duration was 15.3 ± 6 months. Approximately 88.9% had good functional outcome. Conclusion: NMOSDs are a common cause of demyelinating illnesses in Northern India. The response to treatment is excellent and most patients recover without residual disability.

New Treatment Perspectives for Acute Relapses in Neuromyelitis Optica Spectrum Disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is a chronic autoimmune disease of the central nervous system, characterized by recurrent attacks of optic neuritis, transverse myelitis, brainstem, and/ or cerebral symptoms. Despite the current standard of care consisting of high-dose corticosteroids and therapeutic plasma exchange, many patients are left with a permanent neurological disability after each attack. With the recent advancements in understanding the pathogenic mechanisms involved in NMOSD relapses, possibilities to develop new targeted therapies are anticipated. To date, therapies targeted at inhibiting the complement cascade, inhibiting the vascular endothelial growth factor, inhibiting granulocyte migration and degranulation, and depleting B cells have been explored in phase I clinical trials, while other agents are being investigated in preclinical and early clinical trials. This review aims to discuss the potential targets for relapse treatment in NMOSD and provide the readers with a summary of the available data regarding some of the candidate agents for future application in clinical practice.

[Local experience of IL-6 pathway inhibition with satralizumab for patients with neuromyelitis optica spectrum disorder]. / Lokal'nyi opyt primeneniya preparata satralizumab, podavlyayushchego put' IL-6, dlya terapii zabolevanii spektra optikoneiromielita.

Satralizumab is a monoclonal anti-IL6-anibody for patients with neuromyelitis optica or neuromyelitis optica spectrum disorder (NMOSD) seropositive for anti-AQP4-antibody. Satralizumab has been approved in 2021 in the Russian Federation for usage in adults and adolescents from 12 years and older in combination with basic therapy or in monotherapy. The efficacy and safety of satralizumab in comparison with placebo have been demonstrated in two international randomized clinical trials SakuraStar and SakuraSky, phase III. We present clinical experience with satralizumab gained in frames of the Compassionate Use Program that have been initiated in Russia for NMOSD patients. Here, we summarized the results of treatment with satralizumab of 16 patients (14 men and 2 women), aged 13-69 years. Duration of therapy was 9 to 41 week. The first experience of using satralizumab in the Russian Federation in the small group of patients does not yet allow us to draw conclusions about the efficacy due to the short follow-up period. It can be concluded that the safety profile of satralizumab is consistent with the results obtained in international clinical trials. The experience gained in the ongoing program allows us to conclude that satralizumab is a valuable and convenient therapeutical option for seropositive for anti-AQP4-antibodies patients with NMOSD.

Olamkicept(sgp130Fc): The missing trial in Neuromyelitis Optica Spectrum Disorder.

Satralizumab, an antibody against IL-6R, has been recently approved in Neuromyelitis optica spectrum disorder(NMOSD). Targeting IL-6 or IL-6 Receptor(like Satralizumab does) results in inhibition of both pro and anti-inflammatory pathways of IL-6. Sgp130FC(Olamkicept) is a monoclonal antibody that prevents only the proinflammatory pathway of IL-6 to be activated, and could represent a better way to target IL-6 pathway in Neuromyelitis optica spectrum disorder.

Clinical features of organizing pneumonia in anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorders.

BACKGROUND: Anti-aquaporin-4 (AQP4) antibody is an autoantibody marker often observed in patients with neuromyelitis optica spectrum disorder (NMOSD). The pathological relevance of complicated pulmonary disorders in anti-AQP4 antibody-positive NMOSD remains unclear. We aimed to assess the clinical and histological relevance of complicated pulmonary disorders in anti-AQP4 antibody-positive NMOSD. METHODS: We retrospectively reviewed the medical records of 52 patients with anti-AQP4 antibody-positive NMOSD and conducted immunohistochemical evaluations of the lung biopsy specimens. RESULTS: Among 52 patients with anti-AQP4 antibody-positive NMOSD, 4 patients showed pulmonary involvement with a diagnosis of organizing pneumonia (OP). The proportion of males was larger (75% vs. 12.5%; p = 0.013) and creatine kinase levels were higher (458.3 U/L vs. 83.9 U/L; p = 0.003) in patients with OP than in those without OP. OP development preceded or coincided with the NMOSD symptoms. Chest computed tomography findings were consistent with OP in all four patients. Bronchoalveolar lavage fluid predominantly contained lymphocytes. Transbronchial lung biopsy revealed intraluminal plugs of inflammatory debris within the alveoli. Alveolar epithelial cells covering the OP lesions exhibited AQP4 loss, immunoglobulin G deposition, and complement activation. Corticosteroid treatment resulted in clinical improvement of OP. CONCLUSION: OP may be considered a pulmonary manifestation of anti-AQP4 antibody-positive NMOSD beyond the central nervous system. Complement-dependent cytotoxicity of the lung epithelial cells caused by anti-AQP4 antibody is at least partly involved in OP development. When diagnosing NMOSD, the possibility of OP should be carefully evaluated based on the detailed history and chest imaging findings.

Multiple autoimmune disorders in a patient with neuromyelitis optica spectrum disorder presenting with rhabdomyolysis.

Neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disease of the central nervous system characterised by longitudinal extensive transverse myelitis and involvement of the optic nerve and is associated with many autoimmune disorders. The index case, a known case of Hashimoto's thyroiditis, presented with quadriparesis and tea-coloured urine. Investigations revealed ongoing rhabdomyolysis related to autoimmune myositis and autoimmune haemolytic anaemia leading to pigment-induced acute kidney injury. Suspicion of other autoimmune disease prompted an immunological workup, which showed a positive Schirmer's test and a positive anti-nuclear antibody (ANA) antibody test, disclosing Sjögren's syndrome. Lack of improvement in muscle power with corticosteroids despite reduction in muscle enzymes led to an MRI of the spine, which showed longitudinal extensive transverse myelitis and involvement of the intracranial segment of the right optic nerve. These findings, along with a positive test for aquaporin-4 antibodies, confirmed NMOSD. Treatment with cyclophosphamide led to improvement in muscle power to grade 4 at discharge.

Watch out for neuromyelitis optica spectrum disorder onset or clinical relapse after COVID-19 vaccination: What neurologists need to know?

INTRODUCTION: The ongoing global COVID-19 pandemic has dramatically impacted our lives. We conducted this systematic review to investigate the safety of the COVID-19 vaccines in NMOSD patients. METHODS: We systematically searched PubMed, Scopus, Web of Science, and Embase from the beginning of the COVID-19 vaccination to March 1, 2022. Except for the letters, posters, and reviews, we included all related articles to answer two main questions. Our first question examined the occurrence of NMOSD onset as an adverse effect of the COVID-19 vaccine. Our second question investigated the safety of the COVID-19 vaccines in NMOSD patients. RESULTS: Out of 262 records, nine studies, including five studies for the first question and four studies for the second question, met the inclusion criteria. Out of the six patients with NMOSD onset after COVID-19 vaccination, five (83.3%) were female. The median time to NMOSD onset was 6.5 days, and the frequency of the COVID-19 vaccine type was identical in all patients. The most common presentation was longitudinally extensive transverse myelitis, significantly improved by pulse methylprednisolone with or without plasma exchange. The maintenance therapy was described only in three patients: rituximab (n=2) and azathioprine (n=1). Regarding the second question, out of 67 patients, 77.61% were female, with a mean age of 54.75 years old, a mean EDSS of 2.83, and a mean disease duration of 9.5 years. 77% reported at least one preexisting comorbidity. 88.05% were under treatment, most of which were rituximab and azathioprine. 98.50% received two doses of the COVID-19 vaccine. mRNA vaccines were the most commonly used vaccine(86.56%), which were well tolerated. No significant adverse event was reported, and local pain was the most frequently reported. 4.67% of the patients experienced a clinical relapse after a mean interval of 49.75 days, which was mainly mild to moderate in severity. Unfortunately, the data on the COVID-19 vaccines were missing. CONCLUSION: The analysis suggests the safety profile of the COVID-19 vaccines. All NMOSD patients are strongly recommended to vaccinate for COVID-19. To maximize the effectiveness of the COVID-19 vaccines, further studies are needed to draw the best practice for vaccination.

Immunosuppressant and neuromyelitis optica spectrum disorder: optimal treatment duration and risk of discontinuation.

BACKGROUND AND PURPOSE: Preventing relapse by immunosuppressants (ISs) is critical for the prognosis of neuromyelitis optica spectrum disorder (NMOSD); however, the optimal duration of IS treatment is still under discussion. The objective was to explore the optimal duration of IS treatment and the risk of IS discontinuation for NMOSD. METHOD: This cohort study was conducted at a major neurological center that housed the largest NMOSD database in South China. Eligible participants were patients with NMOSD undergoing IS treatment. The main outcome measures were changes in relapse risk based on IS treatment duration, clinical outcomes and predictors of relapse following IS discontinuation. RESULTS: In total, 343 patients were included in this study. The duration of IS treatment was strongly associated with a decrease in relapse risk (hazard ratio [HR] 0.53, p < 0.001). Continuous IS treatment resulted in decreased relapse HRs within 5 years of receiving IS medication, with a mild rebound starting at 5 years. Rituximab reduced the risk of NMOSD relapse to approximately zero within 3 years. The rate of relapse after IS withdrawal was high (77.5%). As opposed to other ISs, a delayed relapse following rituximab withdrawal was observed in this study. Longitudinal extensive transverse myelitis (HR = 2.023, p = 0.006) was associated with a higher risk of relapse after IS discontinuation. CONCLUSIONS: Long-term IS medication for NMOSD is generally suitable. Patients with longitudinal extensive transverse myelitis had a higher risk of relapse after IS discontinuation. Future studies should explore individualized strategies of rituximab maintenance treatment.