Placebo-controlled study in neuromyelitis optica-Ethical and design considerations

B cell and aquaporin-4 antibody relationships with neuromyelitis optica spectrum disorder activity

This post hoc analysis of the randomized, placebo-controlled N-MOmentum study (NCT02200770) of inebilizumab in neuromyelitis optica spectrum disorder (NMOSD) evaluated relationships between circulating B-cell subsets and aquaporin-4 immunoglobulin G (AQP4-lgG) titers and attacks. Among participants receiving placebo, CD20+ and CD27+ B-cell counts were modestly increased from the pre-attack visit to attack; plasmablast/plasma cell gene signature was increased from baseline to the pre-attack visit (p = 0.016) and from baseline to attack (p = 0.009). With inebilizumab treatment, B-cell subset counts decreased and did not increase with attacks. No difference in change of AQP4-IgG titers from baseline to time of attack was observed.

Treatment strategies and responses for attacks of neuromyelitis optica spectrum disorder: A real-world retrospective cohort study

We aimed to assess the treatment strategies utilized in patients with neuromyelitis optica spectrum disorder (NMOSD) experiencing relapses, including their frequency, types, and response after 6 months based on the Expanded Disability Status Scale (EDSS) score.

METHODS

We conducted a retrospective study involving NMOSD patients from the Argentinean MS and NMOSD registry (RelevarEM, NCT03375177). Treatment response at 6 months was categorized as "good" if the EDSS score decreased by ≥1 point after a nadir EDSS score ≤ 3, or by ≥2 points after a nadir EDSS score > 3, "poor" if the EDSS score decrease was slighter, and as "absent" if the EDSS score remained unchanged or worsened.

RESULTS

We included 120 NMOSD patients (seropositive N = 75), who experienced 250 NMOSD-related relapses and received 248 treatments. At 6 months, complete recovery was achieved in 70/98 (71.4%) and 15/19 (79%) patients, respectively. Predictors of a "good" response in our regression model were a younger age at disease onset (OR:3.54, CI95% 2.45-5.01, p < 0.0001) and a short delay from onset of relapse to treatment initiation (OR:1.56, CI95% 1.22-2.13, p = 0.004).

CONCLUSIONS

Approximately two-thirds of patients experienced complete recovery, and younger age and a short delay to start treatment were independent predictors of a "good" response.

Safety and efficacy of inebilizumab for the treatment of neuromyelitis optica spectrum disorder: end-of-study results from the open-label period of the N-MOmentum trial

BACKGROUND

Inebilizumab, an anti-CD19 B-cell-depleting antibody, demonstrated safety and efficacy in neuromyelitis optica spectrum disorder in the randomised controlled period of the N-MOmentum trial. Here, end-of-study data, including the randomised controlled period and open-label extension period, are reported.

METHODS

In the double-blind, randomised, placebo-controlled, phase 2/3 N-MOmentum trial, adults aged 18 years and older with an neuromyelitis optica spectrum disorder diagnosis, Expanded Disability Status Scale score of 8·0 or less, and history of either at least one acute inflammatory attack requiring rescue therapy in the past year or two attacks requiring rescue therapy in the past 2 years, were recruited from 81 outpatient specialty clinics or hospitals in 24 countries. Eligible participants were randomly assigned (3:1), using a central interactive voice system or interactive web response system, and a permuted block randomisation scheme (block size of 4), to receive intravenous inebilizumab (300 mg) or identical placebo on days 1 and 15 of the randomised period, which lasted up to 197 days. Participants and all study staff were masked to treatment assignment. The primary endpoint of the randomised period of the trial was time to onset of adjudicated neuromyelitis optica spectrum disorder attack on or before day 197. Participants in the randomised controlled period who had an adjudicated attack, completed 197 days in the study, or were in the randomised controlled period when enrolment stopped, could voluntarily enter the open-label period. In the open-label period, participants either initiated inebilizumab if assigned placebo (receiving 300 mg on days 1 and 15 of the open-label period) or continued treatment if assigned inebilizumab (receiving 300 mg on day 1 and placebo on day 15, to maintain B-cell depletion and masking of the randomised controlled period). All participants subsequently received inebilizumab 300 mg every 6 months for a minimum of 2 years. The end-of-study analysis endpoints were time to adjudicated attack and annualised attack rate (assessed in all participants who received inebilizumab at any point during the randomised controlled period or open-label period [any inebilizumab population] and the aquaporin-4 [AQP4]-IgG seropositive subgroup [any inebilizumab-AQP4-IgG seropositive population]) and safety outcomes (in all participants who were exposed to inebilizumab, analysed as-treated). This study is registered with ClinicalTrials.gov, NCT02200770, and is now complete.

FINDINGS

Between Jan 6, 2015, and Sept 24, 2018, 467 individuals were screened, 231 were randomly assigned, and 230 received at least one dose of inebilizumab (n=174) or placebo (n=56). Between May 19, 2015, and Nov 8, 2018, 165 (95%) of 174 participants in the inebilizumab group and 51 (91%) of 56 in the placebo group entered the open-label period (mean age 42·9 years [SD 12·4], 197 [91%] of 216 were female, 19 [9%] were male, 115 [53%] were White, 45 [21%] were Asian, 19 [9%] were American Indian or Alaskan Native, and 19 [9%] were Black or African American). As of data cutoff for this end of study analysis (Dec 18, 2020; median exposure 1178 days [IQR 856-1538], total exposure of 730 person-years) 225 participants formed the any inebilizumab population, and 208 (92%) participants were AQP4-IgG seropositive. Overall, 63 adjudicated neuromyelitis optica spectrum disorder attacks occurred in 47 (21%) of 225 treated participants (60 attacks occurred in 44 [21%] of 208 in the AQP4-IgG seropositive subgroup); 40 (63%) of 63 attacks occurred in 34 (15%) of 225 treated participants during the first year of treatment. Of individuals who had an adjudicated attack while receiving inebilizumab, 36 (77%) of 47 were subsequently attack-free at the end of 4 years. Annualised attack rates decreased year-on-year, with end-of-study adjusted annualised attack rates being similar in the any inebilizumab-AQP4-IgG seropositive subgroup (0·097 [95% CI 0·070-0·14]) and any inebilizumab populations (0·092 [0·067-0·13]). Overall, 208 (92%) of 225 participants who received any inebilizumab had at least one treatment-emergent adverse event, the most frequent of which were urinary tract infection (59 [26%]), nasopharyngitis (47 [21%]), and arthralgia (39 [17%]). Infection rates did not increase over 4 years. Three (1%) of 225 participants in the any inebilizumab population died during the open-label period (one each due to a CNS event of unknown cause and pneumonia, respiratory insufficiency resulting from an neuromyelitis optica spectrum disorder attack and viral pneumonia related to COVID-19), all of which were deemed to be unrelated to treatment.

INTERPRETATION

Data from the end-of-study analysis of the N-MOmentum trial showed continued and sustained clinical benefits of long-term inebilizumab treatment in individuals with neuromyelitis optica spectrum disorder, which supports the role of inebilizumab as a CD19+ B-cell-depleting therapy in neuromyelitis optica spectrum disorder.

FUNDING

MedImmune and Viela Bio/Horizon Therapeutics, now part of Amgen.

Exploring the depths of IgG4: insights into autoimmunity and novel treatments

IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.

Therapeutic tactics for targeting B lymphocytes in autoimmunity and cancer

B lymphocytes have become a very popular therapeutic target in a number of autoimmune indications due to their newly appreciated roles, and approachability, in these diseases. Many of the therapies now applied in autoimmunity were initially developed to deplete malignant B cells. These strategies have also been found to benefit patients suffering from such autoimmune diseases as multiple sclerosis, type I diabetes, systemic lupus erythematosus, and rheumatoid arthritis, to name a few. These observations have supported the expansion of research addressing the mechanistic contributions of B cells in these diseases, as well as blossoming of therapeutics that target them. This review seeks to summarize cutting-edge modalities for targeting B cells, including monoclonal antibodies, bispecific antibodies, antibody-drug conjugates, chimeric antigen receptor-T cells, and small molecule inhibitors. Efforts to refine B-cell targeted therapy to eliminate only pathogenic autoreactive cells will be addressed as well as the potential for future B-cell-based cellular therapeutics. Finally, we also address approaches that seek to silence B-cell function without depletion.

Update on the diagnosis and treatment of neuromyelitis optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part II: Attack therapy and long-term management

This manuscript presents practical recommendations for managing acute attacks and implementing preventive immunotherapies for neuromyelitis optica spectrum disorders (NMOSD), a rare autoimmune disease that causes severe inflammation in the central nervous system (CNS), primarily affecting the optic nerves, spinal cord, and brainstem. The pillars of NMOSD therapy are attack treatment and attack prevention to minimize the accrual of neurological disability. Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) are a diagnostic marker of the disease and play a significant role in its pathogenicity. Recent advances in understanding NMOSD have led to the development of new therapies and the completion of randomized controlled trials. Four preventive immunotherapies have now been approved for AQP4-IgG-positive NMOSD in many regions of the world: eculizumab, ravulizumab - most recently-, inebilizumab, and satralizumab. These new drugs may potentially substitute rituximab and classical immunosuppressive therapies, which were as yet the mainstay of treatment for both, AQP4-IgG-positive and -negative NMOSD. Here, the Neuromyelitis Optica Study Group (NEMOS) provides an overview of the current state of knowledge on NMOSD treatments and offers statements and practical recommendations on the therapy management and use of all available immunotherapies for this disease. Unmet needs and AQP4-IgG-negative NMOSD are also discussed. The recommendations were developed using a Delphi-based consensus method among the core author group and at expert discussions at NEMOS meetings.

Inebilizumab reduces neuromyelitis optica spectrum disorder risk independent of FCGR3A polymorphism

Inebilizumab, a humanized, glycoengineered, IgG1 monoclonal antibody that depletes CD19+ B-cells, is approved to treat aquaporin 4 (AQP4) IgG-seropositive neuromyelitis optica spectrum disorder (NMOSD). Inebilizumab is afucosylated and engineered for enhanced affinity to Fc receptor III-A (FCGR3A) receptors on natural killer cells to maximize antibody-dependent cellular cytotoxicity. Previously, the F allele polymorphism at amino acid 158 of the FCGR3A gene (F158) was shown to decrease IgG-binding affinity and reduce rituximab (anti-CD20) efficacy for NMOSD attack prevention. In contrast, our current findings from inebilizumab-treated NMOSD patients indicate similar clinical outcomes between those with F158 and V158 allele genotypes.

Serum neurofilament light chain levels at attack predict post-attack disability worsening and are mitigated by inebilizumab: analysis of four potential biomarkers in neuromyelitis optica spectrum disorder

OBJECTIVE

To investigate relationships between serum neurofilament light chain (sNfL), ubiquitin C-terminal hydrolase L1 (sUCHL1), tau (sTau) and glial fibrillary acidic protein (sGFAP) levels and disease activity/disability in neuromyelitis optica spectrum disorder (NMOSD), and the effects of inebilizumab on these biomarkers in N-MOmentum.

METHODS

N-MOmentum randomised participants to receive inebilizumab or placebo with a randomised controlled period (RCP) of 28 weeks and an open-label follow-up period of ≥2 years. The sNfL, sUCHL1, sTau and sGFAP were measured using single-molecule arrays in 1260 scheduled and attack-related samples from N-MOmentum participants (immunoglobulin G (IgG) autoantibodies to aquaporin-4-positive, myelin oligodendrocyte glycoprotein-IgG-positive or double autoantibody-negative) and two control groups (healthy donors and patients with relapsing-remitting multiple sclerosis).

RESULTS

The concentration of all four biomarkers increased during NMOSD attacks. At attack, sNfL had the strongest correlation with disability worsening during attacks (Spearman R2=0.40; p=0.01) and prediction of disability worsening after attacks (sNfL cut-off 32 pg/mL; area under the curve 0.71 (95% CI 0.51 to 0.89); p=0.02), but only sGFAP predicted upcoming attacks. At RCP end, fewer inebilizumab-treated than placebo-treated participants had sNfL>16 pg/mL (22% vs 45%; OR 0.36 (95% CI 0.17 to 0.76); p=0.004).

CONCLUSIONS

Compared with sGFAP, sTau and sUCHL1, sNfL at attack was the strongest predictor of disability worsening at attack and follow-up, suggesting a role for identifying participants with NMOSD at risk of limited post-relapse recovery. Treatment with inebilizumab was associated with lower levels of sGFAP and sNfL than placebo.

TRIAL REGISTRATION NUMBER

NCT02200770.

How proven is a 'proven intervention'? Ethics of placebo controls in light of conditional approval programs

This article discusses the difficulties of establishing whether there exists a proven therapeutic intervention when regenerative experimental treatments are made accessible to patients under conditional approval programs (outside clinical trials). Conditional approvals are often made on the basis of less robust efficacy evidence than otherwise required for the registration of new treatments. Lower quality of evidence affects the ethical justification of using a placebo-control design. The absence of a proven intervention is important in evaluating whether it is ethically justifiable to use such a design in a clinical trial and is present in major ethical guidelines. The main argument in this paper is that conditionally approved therapies, if referred to as 'proven interventions', would make placebo-control design ethically unjustifiable. Conducting rigorous clinical trials after conditional approvals is crucial to establish the efficacy of therapeutic approaches under such approvals. Hindrances to running such trials and generating further efficacy evidence are brought to attention.

Efficacy and safety of monoclonal antibodies in neuromyelitis optica spectrum disorders: A survival meta-analysis of randomized controlled trials

Background

Monoclonal antibodies such as rituximab (RTX), eculizumab, inebilizumab, satralizumab, and tocilizumab have been found to be effective therapies for neuromyelitis optica spectrum disease ​(NMOSD) in several clinical randomized controlled trials.

Objective

The purpose of this meta-analysis of randomized controlled trials was to assess the efficacy and safety of monoclonal antibodies in the treatment of NMOSD.

Methods

We searched the following databases for relevant English language literature from the establishment of the database to June 2021: PubMed, Embase, Cohorane Library, the Central Register of Controlled Trials (CENTRAL), and Web of Science. Randomized controlled trials of monoclonal antibodies were the targets of the review.

Results

We included seven trials containing 775 patients (485 in the monoclonal antibody group and 290 in the control group). Patients in the monoclonal group (HR 0.24, 95% CI: 0.14 to 0.40, P ​< ​0.00001), as well as patients with seropositive AQP4-IgG (HR 0.18, 95% CI: 0.11 to 0.29, P ​< ​0.00001), both had a higher free recurrence rate than that in the control group. In the first year (HR 0.25, 95% CI: 0.09 to 0.71, P ​= ​0.009) and the second year (HR 0.32, 95% CI: 0.13 to 0.81, P ​= ​0.02), no relapses were documented. The average changes of the expanded disability status scale (EDSS) score decreased by 0.29 (95% CI: -0.09 to 0.51, P ​= ​0.005). Upper respiratory tract infection (OR 1.52, 95% CI: 0.76 to 3.04, P ​= ​0.24), urinary tract infection(OR 0.79, 95% CI: 0.51 to 1.21, P ​= ​0.27), and headache (OR 1.30, 95% CI: 0.78 to 2.17, P ​= ​0.31) were three most frequent adverse reactions.

Conclusions

Monoclonal antibodies are particularly effective treatments in avoiding recurrence for NMOSD patients, according to this meta-analysis. The associated adverse responses are not significantly different from those seen with traditional immunosuppressants.

Current view on the diagnosis and treatment of neuromyelitis optica spectrum disorders exacerbations

Irreversible neurological deficit and disability in neuromyelitis optica spectrum disorders (NOSD) are formed as a result of exacerbations, which are often life-threatening. Timely diagnosis and treatment of exacerbations is a key task in the management of this category of patients. A unified structured approach to the diagnosis and treatment of NOSD exacerbations has not been developed. The purpose of this article is to analyze the scientific literature data on this issue in order to optimize the diagnostics and treatment of NOSD exacerbations in everyday clinical practice. 

Inebilizumab: A Review in Neuromyelitis Optica Spectrum Disorder

Inebilizumab (Uplizna®) is a recently approved monoclonal antibody for use in adults with neuromyelitis optica spectrum disorder (NMOSD) who are anti-aquaporin-4 (AQP4) antibody seropositive. Inebilizumab targets the B cell antigen CD19 and effectively depletes circulating B cells, thus suppressing inflammatory NMOSD attacks that are potentially disabling or life-threatening. It is approved as an intravenous infusion in several countries. In the pivotal phase 2/3 N-MOmentum trial, inebilizumab reduced the risk of NMOSD attacks compared with placebo, including in AQP4-antibody seropositive patients. Inebilizumab also significantly reduced the risk of disability score worsening, the number of NMOSD-related hospitalisations and MRI lesion count, but had no significant effect on low-contrast binocular vision. The treatment effect on relapse risk and disability scores was sustained in inebilizumab-treated patients for ≥ 4 years during the open-label extension. Inebilizumab was generally well tolerated, with the most common adverse events being urinary tract infection and arthralgia. Thus, inebilizumab is an effective treatment option for adults with AQP4-antibody seropositive NMOSD.

The changing landscape of optic neuritis: a narrative review

Optic neuritis (ON) is an inflammatory optic neuropathy that is often a harbinger of central nervous system (CNS) demyelinating disorders. ON is frequently misdiagnosed in the clinical arena, leading to either inappropriate management or diagnostic delays. As a result, patients may fail to achieve optimal recovery. The treatment response to corticosteroids and long term risk of multiple sclerosis was established in the first clinical trials conducted roughly 30 years ago. Spontaneous resolution was observed in the vast majority of patients and intravenous high-dose corticosteroids hastened recovery; half of the patients eventually developed multiple sclerosis. Over the ensuing decades, the number of inflammatory conditions associated with ON has significantly expanded exposing substantial variability in the prognosis, treatment, and management of ON patients. ON subtypes can frequently be distinguished by distinct clinical, serological, and radiological profiles allowing expedited and specialized treatment. Guided by an increased understanding of the immunopathology underlying optic nerve and associated CNS injuries, novel disease management strategies are emerging to minimize vision loss, improve long-term surveillance strategies, and minimize CNS injury and disability. Knowledge regarding the clinical signs and symptoms of different ON subtypes is essential to guide acute therapy, prognosticate recovery, accurately identify underlying CNS inflammatory disorders, and facilitate study design for the next generation of clinical and translational trials.

Hope for patients with neuromyelitis optica spectrum disorders - from mechanisms to trials

Neuromyelitis optica spectrum disorder (NMOSD) is a rare inflammatory CNS disease that primarily manifests as relapsing episodes of severe optic neuritis and myelitis. Diagnosis of NMOSD is supported by the detection of IgG autoantibodies that target the aquaporin 4 (AQP4) water channel, which, in the CNS, is an astrocyte-specific protein. AQP4 antibody binding leads to AQP4 internalization, complement-dependent and antibody-dependent cellular cytotoxicity, and water channel dysfunction. Cumulative attack-related injury causes disability in NMOSD, so the prevention of attacks is expected to prevent disability accrual. Until recently, no regulator-approved therapies were available for NMOSD. Traditional immunosuppressant therapies, including mycophenolate mofetil, azathioprine and rituximab, were widely used but their benefits have not been assessed in controlled studies. In 2019 and 2020, five phase II and III randomized placebo-controlled trials of four mechanism-based therapies for NMOSD were published and demonstrated that all four effectively prolonged the time to first relapse. All four drugs were monoclonal antibodies: the complement C5 antibody eculizumab, the IL-6 receptor antibody satralizumab, the B cell-depleting antibody inebilizumab, which targets CD19, and rituximab, which targets CD20. We review the pathophysiology of NMOSD, the rationale for the development of these mechanism-based drugs, the methodology and outcomes of the five trials, and the implications of these findings for the treatment of NMOSD.

Network Meta-analysis of Food and Drug Administration-approved Treatment Options for Adults with Aquaporin-4 Immunoglobulin G-positive Neuromyelitis Optica Spectrum Disorder

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease defined by attacks on the central nervous system that cause irreversible damage. Recent approval of NMOSD therapies warrants investigations of comparative efficacy to inform treatment decisions.

METHODS

A network meta-analysis (NMA) of all U.S. Food and Drug Administration-approved therapies (eculizumab, inebilizumab, and satralizumab) for adults with aquaporin-4 immunoglobulin G-positive (AQP4+) NMOSD was conducted via a systematic literature review (SLR) using data from randomized controlled trials (RCTs). Database searches of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were executed for the SLR. A fixed-effects proportional hazards Bayesian NMA was used to estimate relative treatment effects based on data extracted from RCTs identified during the SLR (search end date: 11 September 2020). Four unique RCTs (N-MOmentum, PREVENT, SAkuraSky, and SAkuraStar) were identified, and data from 29 publications were extracted for analysis. Network scenarios describing the most comparable patient population groups (such as by treatment settings) were evaluated in our analyses. Relative treatment effects were evaluated based on time-to-first relapse and were expressed as hazard ratios (HRs) with 95% credible intervals (CrIs).

RESULTS

In patients treated with a monoclonal antibody only, eculizumab was associated with a lower risk of relapse compared with satralizumab (HR 0.10, 95% CrI 0.01, 0.65) and inebilizumab (HR 0.11, 95% CrI 0.02, 0.68). In patients treated with monoclonal antibody with or without background immunosuppressive therapy (IST), patients treated with eculizumab ± IST were also less likely to relapse than patients treated with satralizumab ± IST (HR 0.24, 95% CrI 0.06, 0.98).

CONCLUSION

The NMA results suggest that complement component 5 (C5) inhibition prevents NMOSD relapses more effectively than broader mechanisms of action.

Long-term efficacy and safety of inebilizumab in neuromyelitis optica spectrum disorder: Analysis of aquaporin-4-immunoglobulin G-seropositive participants taking inebilizumab for ⩾4 years in the N-MOmentum trial

Background:

Efficacy and safety of inebilizumab for treatment of neuromyelitis optica spectrum disorder in adults seropositive for aquaporin-4 (AQP4)–immunoglobulin (Ig) G were demonstrated in the 28-week randomized controlled period of the N-MOmentum study.

Objective:

To assess efficacy and safety of long-term inebilizumab treatment.

Methods:

Post hoc analysis was performed in 75 AQP4–IgG–seropositive participants receiving inebilizumab for ⩾4 years in the randomized controlled period and open-label extension of the N-MOmentum study.

Results:

Eighteen attacks occurred in 13 participants during inebilizumab treatment (annualized attack rate, 0.052 attacks/person-year). Twelve attacks occurred during the first year of treatment, and two each occurred in years 2–4. Disability scores remained stable throughout ⩾4 years of treatment. Inebilizumab was well tolerated, with two (2.7%) serious treatment-emergent adverse events related to inebilizumab and no deaths. Immunoglobulin G levels decreased over time; however, correlation between severe infections and low IgG levels could not be determined because of their small numbers.

Conclusion:

These results from the N-MOmentum study continue to support use of inebilizumab for treatment of neuromyelitis optica spectrum disorder. Furthermore, the findings suggest that efficacy of inebilizumab may be enhanced after the first year of treatment, warranting additional long-term investigation.

Inebilizumab for treatment of neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease characterized by recurrent optic neuritis and transverse myelitis often resulting in severe disability. Anti-AQP4-immunoglobulin G (IgG) is a pathogenic product of CD19-positive plasma cells found in most, but not all, individuals with NMOSD and is associated with immune-mediated neurologic injury. Inebilizumab, an afucosylated humanized IgG1κ, anti-CD19 monoclonal antibody, may target pathogenic CD19-expressing B cells. In a Phase II/III trial, inebilizumab significantly reduced the proportion of participants experiencing an NMOSD attack and was well tolerated versus placebo. Fewer treated participants had worsening disability than those receiving placebo. Inebilizumab was approved in 2020 by the US FDA for treatment of anti-AQP4 antibody positive NMOSD.

Assessing attacks and treatment response rates among adult patients with NMOSD and MOGAD: Data from a nationwide registry in Argentina

We aimed to examine treatment interventions implemented in patients experiencing neuromyelitis optica spectrum disorders (NMOSD) attacks (frequency, types, and response).

Inebilizumab: First Approval

Inebilizumab (Uplizna™; inebilizumab-cdon in the USA) is a humanised anti-CD19 monoclonal antibody being developed by Viela Bio for the treatment of a range of autoimmune diseases associated with CD19-expressing B cells. Inebilizumab targets and depletes CD19-expressing B cells through antibody-dependent cell-mediated cytotoxicity. In June 2020, inebilizumab received its first global approval in the USA for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adult patients who are seropositive for immunoglobulin G autoantibodies against aquaporin-4 (AQP4-IgG). The drug is also undergoing clinical evaluation for kidney transplant desensitization, myasthenia gravis, and IgG4-related disease. This article summarizes the milestones in the development of inebilizumab leading to this first approval for the treatment of AQP4-IgG seropositive NMOSD.

A window into the future? MRI for evaluation of neuromyelitis optica spectrum disorder throughout the disease course

Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, inflammatory disease of the central nervous system marked by relapses often associated with poor recovery and long-term disability. Magnetic resonance imaging (MRI) is recognized as an important tool for timely diagnosis of NMOSD as, in combination with serologic testing, it aids in distinguishing NMOSD from possible mimics. Although the role of MRI for disease monitoring after diagnosis is not as well established, MRI may provide important prognostic information and help differentiate between relapses and pseudorelapses. Increasing evidence of subclinical disease activity and the emergence of newly approved, highly effective immunotherapies for NMOSD adjure us to re-evaluate MRI as a tool to guide optimal treatment selection and escalation throughout the disease course. In this article we review the role of MRI in NMOSD diagnosis, prognostication, disease monitoring, and treatment selection.

Serum Glial Fibrillary Acidic Protein: A Neuromyelitis Optica Spectrum Disorder Biomarker

Objective

Blood tests to monitor disease activity, attack severity, or treatment impact in neuromyelitis optica spectrum disorder (NMOSD) have not been developed. This study investigated the relationship between serum glial fibrillary acidic protein (sGFAP) concentration and NMOSD activity and assessed the impact of inebilizumab treatment.

Methods

N‐MOmentum was a prospective, multicenter, double‐blind, placebo‐controlled, randomized clinical trial in adults with NMOSD. sGFAP levels were measured by single‐molecule arrays (SIMOA) in 1,260 serial and attack‐related samples from 215 N‐MOmentum participants (92% aquaporin 4‐immunoglobulin G‐seropositive) and in control samples (from healthy donors and patients with relapsing–remitting multiple sclerosis).

Results

At baseline, 62 participants (29%) exhibited high sGFAP concentrations (≥170 pg/ml; ≥2 standard deviations above healthy donor mean concentration) and were more likely to experience an adjudicated attack than participants with lower baseline concentrations (hazard ratio [95% confidence interval], 3.09 [1.6–6.1], p = 0.001). Median (interquartile range [IQR]) concentrations increased within 1 week of an attack (baseline: 168.4, IQR = 128.9–449.7 pg/ml; attack: 2,160.1, IQR = 302.7–9,455.0 pg/ml, p = 0.0015) and correlated with attack severity (median fold change from baseline [FC], minor attacks: 1.06, IQR = 0.9–7.4; major attacks: 34.32, IQR = 8.7–107.5, p = 0.023). This attack‐related increase in sGFAP occurred primarily in placebo‐treated participants (FC: 20.2, IQR = 4.4–98.3, p = 0.001) and was not observed in inebilizumab‐treated participants (FC: 1.1, IQR = 0.8–24.6, p > 0.05). Five participants (28%) with elevated baseline sGFAP reported neurological symptoms leading to nonadjudicated attack assessments.

Interpretation

Serum GFAP may serve as a biomarker of NMOSD activity, attack risk, and treatment effects. ANN NEUROL 2021;89:895–910

Disability Outcomes in the N-MOmentum Trial of Inebilizumab in Neuromyelitis Optica Spectrum Disorder

Objective

To assess treatment effects on Expanded Disability Status Scale (EDSS) score worsening and modified Rankin Scale (mRS) scores in the N-MOmentum trial of inebilizumab, a humanized anti-CD19 monoclonal antibody, in participants with neuromyelitis optica spectrum disorder (NMOSD).

Methods

Adults (N = 230) with aquaporin-4 immunoglobulin G-seropositive NMOSD or -seronegative neuromyelitis optica and an EDSS score ≤8 were randomized (3:1) to receive inebilizumab 300 mg or placebo on days 1 and 15. The randomized controlled period (RCP) was 28 weeks or until adjudicated attack, with an option to enter the inebilizumab open-label period. Three-month EDSS-confirmed disability progression (CDP) was assessed using a Cox proportional hazard model. The effect of baseline subgroups on disability was assessed by interaction tests. mRS scores from the RCP were analyzed by the Wilcoxon-Mann-Whitney odds approach.

Results

Compared with placebo, inebilizumab reduced the risk of 3-month CDP (hazard ratio [HR]: 0.375; 95% CI: 0.148–0.952; p = 0.0390). Baseline disability, prestudy attack frequency, and disease duration did not affect the treatment effect observed with inebilizumab (HRs: 0.213–0.503; interaction tests: all p > 0.05, indicating no effect of baseline covariates on outcome). Mean EDSS scores improved with longer-term treatment. Inebilizumab-treated participants were more likely to have a favorable mRS outcome at the end of the RCP (OR: 1.663; 95% CI: 1.195–2.385; p = 0.0023).

Conclusions

Disability outcomes were more favorable with inebilizumab vs placebo in participants with NMOSD.

Classification of Evidence

This study provides Class II evidence that for patients with NMOSD, inebilizumab reduces the risk of worsening disability. N-MOmentum is registered at ClinicalTrials.gov: NCT02200770.

Recent advances in the treatment of neuromyelitis optica spectrum disorders

PURPOSE OF REVIEW

This review examines recently published randomized placebo-controlled trials for the treatment of neuromyelitis optica spectrum disorders (NMOSD).

RECENT FINDINGS

Until recently, treatments for NMOSD were used-off label and had not been subjected to randomized placebo-controlled trials. Increased understanding of the pathophysiology of NMOSD, particularly aquaporin-4-IgG seropositive NMOSD, lead to the investigation of eculizumab, inebilizumab, and satralizumab for maintenance therapy. Eculizumab inhibits the cleavage of the terminal complement protein C5, inebilizumab depletes immune cells of B-lymphocyte lineage, and satralizumab inhibits interleukin-6 receptors. International, phase 3, randomized, placebo-controlled trials have demonstrated that each of these therapies reduces the risk of NMOSD relapse. In some cases, the studied therapies were administered in conjunction with other immunosuppressants. Each therapy has important safety considerations, notably risk of meningococcal infection with eculizumab and risks of infection and hypogammaglobulinemia with inebilizumab. Reviewing trial design highlights future areas of inquiry for the treatment of NMOSD.

SUMMARY

Eculizumab, inebilizumab, and satralizumab are effective maintenance therapies approved for the treatment of AQP-4 seropositive NMOSD.

Sensitivity analysis of the primary endpoint from the N-MOmentum study of inebilizumab in NMOSD

Background:

In the N-MOmentum trial, the risk of an adjudicated neuromyelitis optica spectrum disorder (NMOSD) attack was significantly reduced with inebilizumab compared with placebo.

Objective:

To demonstrate the robustness of this finding, using pre-specified sensitivity and subgroup analyses.

Methods:

N-MOmentum is a prospective, randomized, placebo-controlled, double-masked trial of inebilizumab, an anti-CD19 monoclonal B-cell-depleting antibody, in patients with NMOSD. Pre-planned and post hoc analyses were performed to evaluate the primary endpoint across a range of attack definitions and demographic groups, as well as key secondary endpoints.

Results:

In the N-MOmentum trial (ClinicalTrials.gov: NCT02200770), 174 participants received inebilizumab and 56 received placebo. Attack risk for inebilizumab versus placebo was consistently and significantly reduced, regardless of attack definition, type of attack, baseline disability, ethnicity, treatment history, or disease course (all with hazard ratios < 0.4 favoring inebilizumab, p < 0.05). Analyses of secondary endpoints showed similar trends.

Conclusion:

N-MOmentum demonstrated that inebilizumab provides a robust reduction in the risk of NMOSD attacks regardless of attack evaluation method, attack type, patient demographics, or previous therapy.

The N-MOmentum study is registered at ClinicalTrials.gov: NCT2200770.

Experience of Using Adrenocorticotropic Hormone in the Treatment of Patients With Acute Neuromyelitis Optica Who Failed Systemic Steroids: A Case Series

OBJECTIVES

Neuromyelitis optica (NMO) has a complex pathology. Clinical symptoms, derived from damage to optic nerves and spinal cord, cause optic neuritis and/or longitudinally extensive myelitis. Treatment options are limited. We assessed adrenocorticotropic hormone (ACTH) use in patients developing exacerbations on systemic steroid treatment and declining other treatments.

METHODS

Patients with NMO who initiated intravenous methylprednisolone (IVMP) for exacerbations and experienced a subsequent exacerbation on monthly IVMP or had inadequate response to IVMP received ACTH 80 U/d intramuscularly for 7 days (for acute relapse), followed by 80 U every 2 weeks (for long taper down/maintenance). Every 1 to 3 months, relapse, Expanded Disability Status Scale, laboratory, and adverse event assessments were performed.

RESULTS

Six patients (mean age: 48.6 years; NMO-suggestive clinical/imaging presentations; cerebral spinal fluid revealing no oligoclonal bands; aquaporin-4 positive [n = 5]) were identified: 5 experiencing subsequent exacerbations with monthly IVMP and 1 with inadequate response to IVMP. No relapses occurred during ACTH treatment or taper-down period, laboratory values indicated no safety concerns, and annual follow-up magnetic resonance imagings were stable. Adverse events were generally characterized as improved or unchanged versus with IVMP, although 1 patient reported transient edema (lower extremities) only during ACTH treatment. Potential treatment-related AEs included edema, acne, urinary tract infection, and insomnia and were reportedly less severe with ACTH treatment than IVMP.

CONCLUSIONS

Adrenocorticotropic hormone treatment for acute NMO was associated with clinical improvement, suggesting that ACTH could have a role in treating acute NMO patients failing IVMP and declining other treatments. Fewer/less severe AEs were observed with ACTH versus IVMP. Larger, controlled clinical studies are needed.

Thymus-derived B cell clones persist in the circulation after thymectomy in myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular, autoimmune disease caused by autoantibodies that target postsynaptic proteins, primarily the acetylcholine receptor (AChR) and inhibit signaling at the neuromuscular junction. The majority of patients under 50 y with AChR autoantibody MG have thymic lymphofollicular hyperplasia. The MG thymus is a reservoir of plasma cells that secrete disease-causing AChR autoantibodies and although thymectomy improves clinical scores, many patients fail to achieve complete stable remission without additional immunosuppressive treatments. We speculate that thymus-associated B cells and plasma cells persist in the circulation after thymectomy and that their persistence could explain incomplete responses to resection. We studied patients enrolled in a randomized clinical trial and used complementary modalities of B cell repertoire sequencing to characterize the thymus B cell repertoire and identify B cell clones that resided in the thymus and circulation before and 12 mo after thymectomy. Thymus-associated B cell clones were detected in the circulation by both mRNA-based and genomic DNA-based sequencing. These antigen-experienced B cells persisted in the circulation after thymectomy. Many circulating thymus-associated B cell clones were inferred to have originated and initially matured in the thymus before emigration from the thymus to the circulation. The persistence of thymus-associated B cells correlated with less favorable changes in clinical symptom measures, steroid dose required to manage symptoms, and marginal changes in AChR autoantibody titer. This investigation indicates that the diminished clinical response to thymectomy is related to persistent circulating thymus-associated B cell clones.

New therapies for neuromyelitis optica spectrum disorder

BACKGROUND

Neuromyelitis optica spectrum disorder is an autoimmune disease of the CNS that primarily affects the optic nerves and spinal cord. Most patients have serum antibodies targeting the aquaporin-4 water channel expressed on the end-feet of astrocytes. Although the prevalence of neuromyelitis optica spectrum disorder is limited to around 1-2 people per 100 000, severe immune-mediated attacks can quickly lead to blindness and paralysis if undiagnosed and untreated. However, diagnosis is straightforward when the highly specific serum aquaporin-4 antibodies are detected with cell-based assays.

RECENT DEVELOPMENTS

Four randomised controlled trials have tested the efficacy of three new therapies (eculizumab, satralizumab, and inebilizumab) for patients with neuromyelitis optica spectrum disorder that all showed a benefit in preventing future attacks. These therapies have different targets within the immune pathogenic process, and the four trials have similarities and differences that mean they might change the therapeutic landscape for people with neuromyelitis optica spectrum disorder in different ways. Efficacy, safety, tolerability, and practical considerations, including potential cost, differ for each drug and might affect the rate of use in real-world populations of patients with neuromyelitis optica spectrum disorder. WHERE NEXT?: Despite the rarity of neuromyelitis optica spectrum disorder, a relative abundance of preventive treatment options now exists. In the future, trials should focus on areas of unmet need, including aquaporin-4 seronegative disease, and on development of treatments for acute relapses and for recovery from autoimmune attacks in the CNS.

Emerging drugs for the treatment of neuromyelitis optica

INTRODUCTION

Evidence-based treatment options for neuromyelitis optica spectrum disorders (NMOSD) patients are beginning to enter the market. Where previously, there was only the exclusive use of empiric and off-label immunosuppressants in this rare and devastating central nervous system autoimmune disease.

AREAS COVERED

In accordance to expanding pathogenetic insights, drugs in phase II and III clinical trials are presented in the context of the current treatment situation for acute attacks and immunopreventative strategies in NMOSD. Some such drugs are the 2019-approved complement inhibitor eculizumab, other compounds in late development include its modified successor ravulizumab, IL-6 receptor antibody satralizumab, CD19 targeting antibody inebilizumab and the TACI-Fc fusion protein telitacicept.

EXPERT OPINION

Moving from broad immunosuppression to tailored treatment strategies, the prospects for efficient NMOSD therapy are positive. For the first time in this disease, class I treatment evidence is available, but long-term data will be necessary to confirm the overall promising study results of the compounds close to approval. While drug development still centers around AQP4 antibody seropositive patients, current and future research requires consideration of possible diverging treatment demands for the smaller group of seronegative patients and patients with presence of MOG antibodies.

Visualizing the Central Nervous System: Imaging Tools for Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are autoimmune central nervous system conditions with increasing incidence and prevalence. While MS is the most frequent inflammatory CNS disorder in young adults, NMOSD is a rare disease, that is pathogenetically distinct from MS, and accounts for approximately 1% of demyelinating disorders, with the relative proportion within the demyelinating CNS diseases varying widely among different races and regions. Most immunomodulatory drugs used in MS are inefficacious or even harmful in NMOSD, emphasizing the need for a timely and accurate diagnosis and distinction from MS. Despite distinct immunopathology and differences in disease course and severity there might be considerable overlap in clinical and imaging findings, posing a diagnostic challenge for managing neurologists. Differential diagnosis is facilitated by positive serology for AQP4-antibodies (AQP4-ab) in NMOSD, but might be difficult in seronegative cases. Imaging of the brain, optic nerve, retina and spinal cord is of paramount importance when managing patients with autoimmune CNS conditions. Once a diagnosis has been established, imaging techniques are often deployed at regular intervals over the disease course as surrogate measures for disease activity and progression and to surveil treatment effects. While the application of some imaging modalities for monitoring of disease course was established decades ago in MS, the situation is unclear in NMOSD where work on longitudinal imaging findings and their association with clinical disability is scant. Moreover, as long-term disability is mostly attack-related in NMOSD and does not stem from insidious progression as in MS, regular follow-up imaging might not be useful in the absence of clinical events. However, with accumulating evidence for covert tissue alteration in NMOSD and with the advent of approved immunotherapies the role of imaging in the management of NMOSD may be reconsidered. By contrast, MS management still faces the challenge of implementing imaging techniques that are capable of monitoring progressive tissue loss in clinical trials and cohort studies into treatment algorithms for individual patients. This article reviews the current status of imaging research in MS and NMOSD with an emphasis on emerging modalities that have the potential to be implemented in clinical practice.

Autoimmune Pathology in Myasthenia Gravis Disease Subtypes Is Governed by Divergent Mechanisms of Immunopathology

Myasthenia gravis (MG) is a prototypical autoantibody mediated disease. The autoantibodies in MG target structures within the neuromuscular junction (NMJ), thus affecting neuromuscular transmission. The major disease subtypes of autoimmune MG are defined by their antigenic target. The most common target of pathogenic autoantibodies in MG is the nicotinic acetylcholine receptor (AChR), followed by muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4). MG patients present with similar symptoms independent of the underlying subtype of disease, while the immunopathology is remarkably distinct. Here we highlight these distinct immune mechanisms that describe both the B cell- and autoantibody-mediated pathogenesis by comparing AChR and MuSK MG subtypes. In our discussion of the AChR subtype, we focus on the role of long-lived plasma cells in the production of pathogenic autoantibodies, the IgG1 subclass mediated pathology, and contributions of complement. The similarities underlying the immunopathology of AChR MG and neuromyelitis optica (NMO) are highlighted. In contrast, MuSK MG is caused by autoantibody production by short-lived plasmablasts. MuSK MG autoantibodies are mainly of the IgG4 subclass which can undergo Fab-arm exchange (FAE), a process unique to this subclass. In FAE IgG4, molecules can dissociate into two halves and recombine with other half IgG4 molecules resulting in bispecific antibodies. Similarities between MuSK MG and other IgG4-mediated autoimmune diseases, including pemphigus vulgaris (PV) and chronic inflammatory demyelinating polyneuropathy (CIDP), are highlighted. Finally, the immunological distinctions are emphasized through presentation of biological therapeutics that provide clinical benefit depending on the MG disease subtype.

Treatment of neuromyelitis optica spectrum disorders

PURPOSE OF REVIEW

This review discusses concepts for diagnosing neuromyelitis optica spectrum disorders (NMOSD), distinguishing NMOSD from other inflammatory diseases of the central nervous system, and highlights recent and forthcoming data on acute and maintenance therapy of NMOSD.

RECENT FINDINGS

The neurologic manifestations of NMOSD are heterogenous, extending beyond classic presentations of optic neuritis and longitudinally extensive transverse myelitis. NMOSD may be comorbid with rheumatologic diseases, such as systemic lupus erythematosus, but is recognized as a distinct entity. Recent studies of acute treatment of NMOSD support early use of plasmapheresis. Relapse prevention is essential, as relapses can be disabling and patients may have only partial recovery. Current practice generally recommends at least 5 years of maintenance treatment. Recent randomized data demonstrates superiority of rituximab over azathioprine. Phase 3 trials have recently been completed or are underway studying novel therapies employing B-cell depletion, complement inhibition, and cell-based mechanisms (among other mechanisms) for maintenance therapy of NMOSD.

SUMMARY

NMOSD is a heterogeneous but well-defined clinical entity, distinct from other neurologic and systemic inflammatory diseases, and treatment is poised for expansion.

Diagnostic procedures in suspected attacks in patients with neuromyelitis optica spectrum disorders: Results of an international survey

BACKGROUND

Currently, there is no evidence-based definition of attacks in neuromyelitis optica spectrum disorders (NMOSD). However, to allow their stringent use as valid endpoints, recent phase III trials in NMOSD defined criteria and adjudication of these events in context of these trials. The objective of this study was to investigate diagnostic procedures currently used in routine adjudication of suspected attacks in NMOSD, and to assess whether the standardized attack-criteria from two pivotal trials may be feasible in routine clinical care.

METHODS

Four global clinical networks were surveyed using an online questionnaire: NEMOS (Neuromyelitis Optica Study Group), IMSVISUAL (International Multiple Sclerosis Visual System Consortium), GJCF-ICC (Guthy Jackson Charitable Foundation-International Clinical Consortium) and NOMADMUS (Devic's neuromyelitis optica and related neurological disorders study group).

RESULTS

Seventy-eight responses were received from September 2018 to February 2019. Median annual number of patients seen with suspected attacks was 10 (range 2-130). Immediate access to MRI was reported by 59.0% of all participants and the majority performs an MRI for new patients with a myelitis, optic neuritis or other symptoms. In patients with established NMOSD diagnosis presenting during routine clinical visits only 10.5% or 9.2% always perform a brain or spinal cord MRI, respectively. Digital records of patients' visits are kept by 98.7% of all participants and 88.5% have direct access to case history. An expert neurological examination is performed for 94.9% of participants reported to perform an expert neurological examination in patients with acute attacs, while only 30.8% seem to perform the assessments according to the Neurostatus-Expanded Disability Status Scale (EDSS) definitions.. The Sakura Star study criteria which are based solely on clinical assessment could be feasible in routine care, provided that more centers use the Neurostatus-EDSS, while only 9% of participants fulfill all requirements for adjudication of the N-Momentum study criteria.

CONCLUSIONS

The high percentage of centers using digital records is encouraging. However, routine adjudication of clinical events in NMOSD seems highly heterogeneous. MRI is the mainstay in the majority of queried centers, but its immediate availability is limited. Only a minority of centers are equipped for trial-grade classification of attacks, if this is not solely clinically based. Thus, standard and feasible guidelines for attack adjudication are urgently needed to standardize routine care, optimize future clinical trials and allow studying long-term safety and efficacy of newly approved drugs in phase IV trials.

Neuromyelitis optica spectrum disorders with unevenly clustered attack occurrence

Objective

The aim of this study was to elucidate the characteristics of clinical attacks in neuromyelitis optica spectrum disorders (NMOSDs) with positive serum anti-aquaporin-4 antibody. Both the timing and sequential pattern of clinical types were analyzed.

Methods

A total of 69 patients with NMOSD were enrolled in this study, all of whom were treated at a single university hospital. All data regarding the clinical attacks (including types and date) together with other clinical information were collected.

Results

Analysis of clinical attacks from the enrolled patients showed that there were 2 distributional patterns of attack occurrence in each patient: (1) “clustered” occurrences, which occurred within 12 months from the previous attack, and (2) “nonclustered” intermittent occurrences, which occurred ≥12 months after the previous attack. These occurrences were regardless of the duration from the onset. During the “clustered” period, clinical attacks were more likely to show a similar clinical manifestation, such as optic neuritis or myelitis. After entering the “nonclustered” intermittent period, the relapses were of random clinical type, regardless of the previous clinical manifestation.

Conclusions

Patients with NMOSD showed mixed periods of “clustered” occurrence with frequent attacks presenting with similar manifestations and “nonclustered” intermittent periods with sparse relapses. Approximately half of the relapses occurred during the “clustered” period within 12 months of the last clinical attack. Clinicians should pay special attention to whether the patients are presently in the “clustered” or “nonclustered” period to decide optimal relapse-preventive strategies.

Inebilizumab for the treatment of neuromyelitis optica spectrum disorder (N-MOmentum): a double-blind, randomised placebo-controlled phase 2/3 trial

BACKGROUND

No approved therapies exist for neuromyelitis optica spectrum disorder (NMOSD), a rare, relapsing, autoimmune, inflammatory disease of the CNS that causes blindness and paralysis. We aimed to assess the efficacy and safety of inebilizumab, an anti-CD19, B cell-depleting antibody, in reducing the risk of attacks and disability in NMOSD.

METHODS

We did a multicentre, double-blind, randomised placebo-controlled phase 2/3 study at 99 outpatient specialty clinics or hospitals in 25 countries. Eligible participants were adults (≥18 years old) with a diagnosis of NMOSD, an Expanded Disability Status Scale score of 8·0 or less, and a history of at least one attack requiring rescue therapy in the year before screening or at least two attacks requiring rescue therapy in the 2 years before screening. Participants were randomly allocated (3:1) to 300 mg intravenous inebilizumab or placebo with a central interactive voice response system or interactive web response system and permuted block randomisation. Inebilizumab or placebo was administered on days 1 and 15. Participants, investigators, and all clinical staff were masked to the treatments, and inebilizumab and placebo were indistinguishable in appearance. The primary endpoint was time to onset of an NMOSD attack, as determined by the adjudication committee. Efficacy endpoints were assessed in all randomly allocated patients who received at least one dose of study intervention, and safety endpoints were assessed in the as-treated population. The study is registered with ClinicalTrials.gov, number NCT02200770.

FINDINGS

Between Jan 6, 2015, and Sept 24, 2018, 230 participants were randomly assigned to treatment and dosed, with 174 participants receiving inebilizumab and 56 receiving placebo. The randomised controlled period was stopped before complete enrolment, as recommended by the independent data-monitoring committee, because of a clear demonstration of efficacy. 21 (12%) of 174 participants receiving inebilizumab had an attack versus 22 (39%) of 56 participants receiving placebo (hazard ratio 0·272 [95% CI 0·150-0·496]; p<0·0001). Adverse events occurred in 125 (72%) of 174 participants receiving inebilizumab and 41 (73%) of 56 participants receiving placebo. Serious adverse events occurred in eight (5%) of 174 participants receiving inebilizumab and five (9%) of 56 participants receiving placebo.

INTERPRETATION

Compared with placebo, inebilizumab reduced the risk of an NMOSD attack. Inebilizumab has potential application as an evidence-based treatment for patients with NMOSD.

FUNDING

MedImmune and Viela Bio.

Review: Recent advances in the understanding of the pathophysiology of neuromyelitis optica spectrum disorder

Neuromyelitis optica is an autoimmune inflammatory disorder of the central nervous system that preferentially targets the spinal cord and optic nerve. Following the discovery of circulating antibodies against the astrocytic aquaporin 4 (AQP4) water channel protein, recent studies have expanded our knowledge of the unique complexities of the pathogenesis of neuromyelitis optica and its relationship with the immune response. This review describes and summarizes the recent advances in our understanding of the molecular mechanisms underlying neuromyelitis optica disease pathology and examines their potential as therapeutic targets. Additionally, we update the most recent research by proposing major unanswered questions regarding how peripheral AQP4 antibodies are produced and their entry into the central nervous system, the causes of AQP4-IgG-seronegative disease, why peripheral AQP4-expressing organs are spared from damage, and the impact of this disease on pregnancy.

Secondary antibody deficiency in neurology

PURPOSE OF REVIEW

Induction of lymphocyte depletion is increasingly used as a therapeutic strategy for central and peripheral neuroinflammatory disease. However, there is also a growing recognition of the treatment-related complication of secondary antibody deficiency (SAD). Although the occurrence of hypogammaglobulinaemia is a recognized phenomenon during immunomodulation, robust data on the coexistence of impaired responses to immunization, and significant and/or atypical infections is scarce. Here we review the literature on SAD in anti-CD20 therapy.

RECENT FINDINGS

Several factors that may increase the incidence of SAD have now been identified, including low levels of immunoglobulins prior to the commencement of B-cell ablation therapy, duration of maintenance therapy, and concurrent or prior use of other immunosuppressing agents such as cyclophosphamide and steroids. Measurement of disease-specific antibodies and vaccine response are likely to be helpful adjuncts to measurement of serum immunoglobulin levels during B-cell depleting therapy. Supportive treatment may include amending the treatment schedule to limit cumulative dose.

SUMMARY

B-cell depleting agents offer considerable therapeutic benefit in neurology. We propose modifications in current practice that include risk stratification and early identification of SAD, with the aim of minimising morbidity and mortality related to this underappreciated condition.

[Optical coherence tomography in neuromyelitis optica spectrum disorders]

Neuromyelitis optica spectrum disorders (NMOSD) are mostly relapsing inflammatory conditions of the central nervous system (CNS). In 55% of the cases of NMOSD optic neuritis (ON) is the most frequent first manifestation and can cause severe damage to the afferent visual system and the retina with resultant severe visual impairment. In recent years, investigations of the retina as part of the CNS by optical coherence tomography (OCT) has been shown to be a valid and efficient method for diagnostics and evaluation of the disease course in NMOSD. In addition, OCT not only shows severe damage of the afferent visual system due to multiple bouts of ON but also reveals NMOSD-specific intraretinal pathologies. The latter could be just as important for future differential diagnostics as for the evaluation of potential therapeutic targets. This article briefly reviews the principles of the OCT technique and describes its relevance for the diagnostics and assessment of disease course in NMOSD.

Rituximab in neurological disease: principles, evidence and practice

Rituximab is a widely used B-cell-depleting monoclonal antibody. It is unlicensed for use in neurological disorders and there are no treatment guidelines. However, as a rapidly acting, targeted therapy with growing evidence of efficacy and tolerability in several neuroinflammatory disorders, it is an attractive alternative to conventional immunomodulatory medications. This practical review aims to explain the basic principles of B-cell depletion with therapeutic monoclonal antibodies. We present the evidence for using rituximab in neurological diseases, and describe the practical aspects of prescribing, including dosing, monitoring, safety, treatment failure and its use in special circumstances such as coexisting viral hepatitis, pregnancy and lactation. We provide an administration guide, checklist and patient information leaflet, which can be adapted for local use. Finally, we review the safety data of rituximab and ocrelizumab (a newer and recently licensed B-cell-depleting therapy for multiple sclerosis) and suggest monitoring and risk reduction strategies.

B cell depletion in the treatment of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. The latest development of B-cell depletion by anti-CD20 monoclonal antibodies has been a large step forward in the treatment of this devastating disease.

AREAS COVERED

In this manuscript, we review mechanisms of action, efficacy, safety, and tolerance of anti-CD20 therapies for MS, including rituximab, ocrelizumab, and ofatumumab.

EXPERT OPINION

B-cell depletion efficiently suppresses acute inflammatory disease activity in relapsing-remitting MS (RRMS), and may slowdown progression in primary progressive MS (PPMS). The treatment is generally well tolerated, with manageable adverse events related to infusion reactions and infections. Ocrelizumab, a humanized anti-CD20 monoclonal antibody, is the first therapy to be approved for the treatment of both RRMS and PPMS.

Clinical characteristics of 153 Brazilian patients with neuromyelitis optica spectrum disorder (NMOSD)

BACKGROUND

The 2015 criteria for diagnosing neuromyelitis optica spectrum disorder (NMOSD) have encouraged several groups across the world to report on their patients using these criteria. The disease typically manifests with severe relapses of optic neuritis, longitudinally extensive myelitis and/or brainstem syndromes, often leading to severe disability. Some patients are seropositive for antibodies against aquaporin-4 (AQP4), others are positive for anti-myelin oligodendrocyte glycoprotein (MOG), while a few are negative for both biomarkers. The disease is complex, and only now are specific therapeutic clinical trials being carried out. The present study adds to the literature through detailed clinical data from 153 medical records of Brazilian patients.

METHODS

Retrospective assessment of medical records from nine specialized units in Brazil.

RESULTS

NMOSD was more prevalent in females (4.1:1), who had significantly fewer relapses than males (p = 0.007) but presented similar levels of disability over time. African ancestry was associated with higher levels of disability throughout the disease course (p < 0.001), although the number of relapses was similar to that observed in white patients. Concomitant autoimmune diseases were relatively rare in this population (6.5%). Positivity for anti-AQP4 antibodies was identified in 62% of the patients tested, while 3% presented anti-MOG antibodies. Anti-AQP4 antibodies were not associated to worse disease course. The last medical record showed that six patients had died and 13 were wheelchair-bound. Seventy percent of the patients did not respond to first-line therapy (azathioprine and/or corticosteroids), and five patients continued to relapse even after four different courses of treatment.

CONCLUSION

The present study adds to the reports from other countries presenting original data on Brazilian patients diagnosed with NMOSD according to the 2015 criteria.

Spinal cord lesions and atrophy in NMOSD with AQP4-IgG and MOG-IgG associated autoimmunity

BACKGROUND

Spinal cord (SC) affection is a hallmark symptom of neuromyelitis optica spectrum disorders (NMOSD). Patients with aquaporin-4 (AQP4-IgG+) or myelin oligodendrocyte glycoprotein (MOG-IgG+) antibody seropositivity show this overlapping clinical phenotype.

OBJECTIVE

Quantitative comparison of SC lesions and atrophy in AQP4-IgG+ and MOG-IgG+ NMOSD.

METHODS

AQP4-IgG+ (n = 38), MOG-IgG+ (n = 15) NMOSD patients and healthy controls (HC, n = 24) were analysed for SC lesion (prevalence, length, location), atrophy as mean upper cervical cord area (MUCCA), Expanded Disability Status Scale (EDSS), timed 25-foot walk speed (T25FWS) and 9-hole peg test (9HPT) measures.

RESULTS

In total, 92% (35/38) of AQP4-IgG+ and 53% (8/15) of MOG-IgG+ patients had myelitis attacks (χ² = 6.47, p = 0.011). 65.8%/26.7% of AQP4-/MOG-IgG+ patients had chronic SC lesions (χ² = 5.16, p = 0.023), with similar proportions in cervical, upper thoracic and lower thoracic cord, and no length differences. MUCCA was decreased in AQP4-IgG+ (t = -2.27, p = 0.028), but not MOG-IgG+ patients (t = 0.58, p = 0.57) compared to HC. MUCCA associated with myelitis attacks (rho = -0.33, p = 0.016), EDSS (rho = -0.31, p = 0.030), pyramidal functional score (rho = -0.42, p = 0.003), T25FWS (r = 0.43, p = 0.010) and 9HPT Z-score (r = 0.32, p = 0.037), regardless of antibody status.

CONCLUSION

AQP4-IgG+ patients had more myelitis attacks, SC lesions and SC atrophy was more pronounced than in MOG-IgG+ patients. MUCCA is associated with clinical myelitis attacks and disability in all NMOSD patients.

Diagnosis and Treatment of NMO Spectrum Disorder and MOG-Encephalomyelitis

Neuromyelitis optica spectrum disorders (NMOSD) are autoantibody mediated chronic inflammatory diseases. Serum antibodies (Abs) against the aquaporin-4 water channel lead to recurrent attacks of optic neuritis, myelitis and/or brainstem syndromes. In some patients with symptoms of NMOSD, no AQP4-Abs but Abs against myelin-oligodendrocyte-glycoprotein (MOG) are detectable. These clinical syndromes are now frequently referred to as "MOG-encephalomyelitis" (MOG-EM). Here we give an overview on current recommendations concerning diagnosis of NMOSD and MOG-EM. These include antibody and further laboratory testing, MR imaging and optical coherence tomography. We discuss therapeutic options of acute attacks as well as longterm immunosuppressive treatment, including azathioprine, rituximab, and immunoglobulins.

Area postrema syndrome: Frequency, criteria, and severity in AQP4-IgG-positive NMOSD

Objective

To define the frequency, duration, and severity of intractable nausea, vomiting, or hiccups in aquaporin-4–immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD) and propose diagnostic criteria and a severity scale for area postrema syndrome (APS).

Methods

An International NMOSD database was interrogated for frequency of APS. Patients with AQP4-IgG–positive NMOSD completed an APS symptom questionnaire. Nausea and vomiting severity was derived from the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) score. The diagnostic criteria, severity scale, and immunotherapy response was applied to a prospective validation cohort of patients from multiple centers.

Results

Analysis of an international database for AQP4-IgG–seropositive NMOSD (n = 430) revealed a high prevalence of isolated APS attacks (onset 7.1%–10.3%; subsequent 9.4%–14.5%) across continents. For 100 patients with 157 episodes of APS, nausea (n = 127, 81%) lasted for a median of 14 days (range 2–365), vomiting (113, 72%) with a median of 5 episodes/d (2–40) lasted 1–20 minutes, and hiccups (102, 65%) lasted a median of 14 days (2–365). Symptoms consistently and completely resolved following immunotherapy. Data were used to propose APS diagnostic criteria and repurpose PUQE score (hiccups severity grade based on symptom duration). The clinical utility was demonstrated in a prospective validation cohort.

Conclusion

Isolated APS attacks are frequently encountered both at onset and during the NMOSD course. The diagnostic criteria proposed here will assist clinicians in recognizing APS. Diagnosis of an APS attack earlier than 48 hours is possible if a dorsal medulla lesion is detected. Accurate diagnosis and evaluation of APS attack severity will assist in outcome measurement in NMOSD clinical trials.