Rituximab-induced hypogammaglobulinemia in patients with neuromyelitis optica spectrum disorders

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.

Treatment and outcome of aquaporin-4 antibody-positive NMOSD: A multinational pediatric study

Objective

To describe the clinical phenotypes, treatment response, and outcome of children with antibodies against aquaporin-4 (AQP4-Ab) neuromyelitis optica spectrum disorder (NMOSD).

Methods

Retrospective, multicenter, and multinational study of patients with AQP4-Ab NMOSD aged <18 years at disease onset from a center in Brazil and 13 European centers. Data on demographics, clinical findings, and laboratory results were analyzed; calculation of annualized relapse rates (ARRs) pre- and on-treatment with disease-modifying therapies (DMTs) and of ORs for predictors of poor outcome was performed.

Results

A total of 67 children were identified. At last follow-up (median 4 years, interquartile range 2–10 years), 37/67(57.8%) were found to have permanent disability. A more severe disease course was seen in the non-White ethnicity with both a shorter time to first relapse (p = 0.049) and a worse Expanded Disability Status Scale score at last follow-up (p = 0.008). The median ARR on treatment was 0.18 on azathioprine (n = 39, range 0–4), 0 on mycophenolate mofetil (n = 18, range 0–3), and 0 on rituximab (n = 29, range 0–2). No patient treated with rituximab as first-line therapy relapsed. Optic neuritis at onset was associated with a poor visual outcome below 20/200 (OR 8.669, 95% CI 1.764–42.616, p = 0.008), and a younger age at onset was associated with cognitive impairment (OR 0.786, 95% CI 0.644–0.959, p = 0.018).

Conclusions

AQP4-Ab NMOSD in children is an aggressive disease with permanent disabilities observed in over half the cohort. All DMTs were associated with a reduction of ARR. First-line rituximab prevented further clinical relapses. International consensus on treatment protocols for children is required to reduce heterogeneity of treatment regimens used worldwide.

Classification of evidence

This study provides Class IV evidence that for children with AQP4-Ab NMOSD, all DMTs, particularly first-line rituximab, reduced the ARR and prevented further clinical relapses.

Retrospective Observation of Low-Dose Rituximab Treatment in Chinese Patients With Neuromyelitis Optica Spectrum Disorders in a Real-World Setting

Objective: This study aimed to investigate the efficacy and safety of low-dose rituximab (RTX) in the treatment of neuromyelitis optica spectrum disorders (NMOSD) patients.

Methods: NMOSD patients were treated with RTX at ~25% of the standard dose. The annualized relapse rate (ARR), expanded disability status scale (EDSS) score, visual function system scale (VFSS) and length of spinal cord lesions before and after treatment were statistically compared. The dynamic changes in the proportion of CD19⁺ B lymphocytes after treatment were monitored, and adverse reactions were recorded.

Results: In total, 36 NMOSD patients who received a low-dose RTX treatment (375-mg/m² induction dose and 500 mg every 6 months) were recruited. The mean follow-up time after the RTX treatment was 19.83 ± 7.74 months. After the treatment, the ARR decreased from 1.97 ± 1.93 to 0.12 ± 0.32, the EDSS score decreased from 3.43 ± 1.49 to 3.10 ± 1.88, and the spinal cord lesion length decreased from 5.54 ± 3.96 to 4.31 ± 3.73. These differences were all statistically significant. The subgroup analysis of the patients who had previously received non-steroidal immunosuppressants (NSISs) (n = 20) showed that after the RTX treatment, the ARR decreased from 0.66 ± 0.51 to 0.08 ± 0.26, the EDSS score decreased from 3.65 ± 1.22 to 3.40 ± 1.99, and the spinal cord lesion length decreased from 5.68 ± 3.73 to 4.21 ± 3.58. These differences were all statistically significant. The VFSS scores did not show a significant change. The Kaplan-Meier analysis showed that low-dose RTX significantly delayed recurrence, which was also observed in the subgroup analysis of patients who previously received NSISs. Five relapses in 5 cases were noted after the low-dose RTX administration, and the percentage of CD19⁺ B cells remained < 1% in 3 cases during relapse. During the RTX treatment and subsequent follow-up, 8 (22.2%) patients reported adverse reactions, all of which were minor.

Conclusion: Low-dose RTX is an effective and safe treatment method for NMOSDs. This method is worth popularizing in developing countries or regions, especially in areas where RTX is not covered by medical insurance.

Re-Evaluating the Use of IFN-β and Relapsing Multiple Sclerosis: Safety, Efficacy and Place in Therapy

The advent of interferon therapy for the treatment of multiple sclerosis (MS) was a massive advancement in the field and changed the course of the disease. While the exact mechanism of interferon therapy in MS is unknown, disease control is likely mediated by reducing Th1 and Th17 cells while increasing regulatory T cells and altering the cytokine profile. Interferon therapy not only gave physicians and patients an evidence-based treatment option to treat MS by decreasing relapses and the accrual of disability but it also provided valuable insight into disease pathophysiology that allowed for the development of further treatments. Currently, there are 18 disease-modifying therapies available for the treatment of MS with varying efficacies, routes of administration, and mechanisms. As treatment options in the field have evolved, interferon therapy is less commonly prescribed as first-line therapy, because the newer therapies are more effective and better tolerated. That being said, interferons still have a place in the field in both clinical practice and clinical trial research. In this review, we will summarize the safety and efficacy of interferon therapy and discuss its current place in MS care.

Do plasma cells contribute to the determination of their lifespan?

Longevity of plasma cells is dependent on their ability to access and reside in so-called survival niches that are predominantly located in the bone marrow. It is proposed that by some process a small fraction of the plasma cells generated in response to new antigen challenges can enter into the long-lived repertoire by displacing existing plasma cells. Several lines of research show that this process is not stochastic as not all resident, long-lived plasma cells appear equally likely to be displaced. The basis of these differences might reside in the niches, the plasma cells or a combination of both factors that intersect to create a distribution of susceptibility to replacement and lifespans. In this review, I consider factors that might vary in plasma cells and thus influence their access to niches and the ability of newly generated plasma cells to survive over the long term.

Use of rituximab in adults with relapsing-remitting multiple sclerosis: a systematic literature review

Objective: Rituximab is used as an off-label treatment for relapsing-remitting multiple sclerosis (RRMS); however, the comparative efficacy and safety of rituximab versus currently licensed disease-modifying drugs (DMDs) for RRMS is unknown. A systematic literature review was conducted to evaluate the available data pertaining to efficacy and safety of rituximab in adult patients with RRMS and highly active relapsing multiple sclerosis (HA-RMS); data quality was critically assessed via risk of bias (RoB) assessment.Methods: Biomedical literature databases were searched until mid-2018 and key proceedings were searched from 2016 to 2018. Critical appraisal of non-randomized studies was conducted using the Cochrane RoB assessment tool; randomized controlled trials (RCTs) were appraised using comprehensive assessment criteria based on the NICE guidelines.Results: Thirty-eight unique studies based on 49 publications were identified: 25 RRMS studies (one RCT) and 13 HA-RMS studies (no RCTs). The evidence among patients with RRMS generally favored rituximab in comparison to placebo (relapse rate) and interferons/glatiramer acetate (relapse rate and disability progression), although much of the non-randomized data were descriptive and/or not statistically significant. In comparison to placebo, rituximab was associated with a greater risk of adverse events. Two-thirds of the non-randomized RRMS studies were associated with critical/serious RoB; the single RCT was associated with low RoB. Furthermore, all of the non-randomized HA-RMS studies were associated with critical/serious RoB.Conclusions: Available evidence of off-label rituximab use for the treatment of patients with RRMS suggests generally favorable efficacy versus placebo and interferons/glatiramer acetate; however, the poor quality of the included studies limits any robust conclusions.

Glatiramer acetate immune modulates B-cell antigen presentation in treatment of MS

OBJECTIVE

We examined the effect of glatiramer acetate (GA) on B-cell maturation, differentiation, and antigen presentation in MS and experimental autoimmune encephalomyelitis (EAE).

METHODS

A cross-sectional study of blood samples from 20 GA-treated and 18 untreated patients with MS was performed by flow cytometry; 6 GA-treated patients with MS were analyzed longitudinally. GA-mediated effects on B-cell antigen-presenting function were investigated in EAE, or, alternatively, B cells were treated with GA in vitro using vehicle as a control.

RESULTS

In MS, GA diminished transitional B-cell and plasmablast frequency, downregulated CD69, CD25, and CD95 expression, and decreased TNF-α production, whereas IL-10 secretion and MHC Class II expression were increased. In EAE, we observed an equivalent dampening of proinflammatory B-cell properties and an enhanced expression of MHC Class II. When used as antigen-presenting cells for activation of naive T cells, GA-treated B cells promoted development of regulatory T cells, whereas proinflammatory T-cell differentiation was diminished.

CONCLUSIONS

GA immune modulates B-cell function in EAE and MS and efficiently interferes with pathogenic B cell-T cell interaction.

Tacrolimus is effective for neuromyelitis optica spectrum disorders with or without anti-AQP4 antibody

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) are a group of inflammatory central nervous system disorders characterized by optic neuritis, transverse myelitis, and anti-aquaporin 4 (AQP4) antibody production. However, it has recently been shown that some cases of typical NMOSD can be anti-AQP4 antibody-negative as well. In this study, we retrospectively investigated the disorder relapse-suppressing effect of tacrolimus (TAC) when combined with prednisolone (PSL) in anti-AQP4 antibody-positive and -negative NMOSD cases.

METHODS

Subjects were NMOSD outpatients treated at our hospital in August 2016 who fulfilled the 2015 International Panel for NMO Diagnosis criteria and whose medical history before visiting our department was known; anti-myelin oligodendrocyte glycoprotein antibody-positive cases were excluded. We retrospectively investigated the annualized relapse rate (ARR) before and after combined TAC and PSL treatment in 50 NMOSD cases who had been using TAC with PSL for at least 1 year and whom we were also able to observe.

RESULTS

There were 42 anti-AQP4 antibody-positive cases and 8 negative cases. Observation periods of the anti-AQP4 antibody-positive cases were 1.1 years before TAC and 5.1 years after TAC. ARR before TAC was 1.0 and 0.08 after TAC, indicating a relapse-suppression rate of 92% (p < 0.001) and clear improvement. In the anti-AQP4 antibody-negative group, the observation period was 5.6 years before and 4.1 years after TAC. ARR before TAC was 0.5 and 0.07 after TAC. The relapse-suppression rate was 86% (p < 0.05), which was obviously as effective as in the anti-AQP4 antibody-positive group. PSL dose in the anti-AQP4 antibody-positive group was 15.0 mg/day at the start of TAC and was reduced to 6.3 mg/day after 2 years (p < 0.001). The Expanded Disability Status Scale (EDSS) score decreased from 4.5 at the start of TAC to 2.0 after 2 years in the anti-AQP4 antibody-positive group (p < 0.05), which was a clear improvement.

CONCLUSION

Combined use of TAC with PSL clearly suppressed relapse of both anti-AQP4 antibody-positive and -negative NMOSD. In the anti-AQP4 antibody-positive group, both PSL dose and EDSS score decreased compared with the dose at the start of the study.

Pediatric NMOSD: A Review and Position Statement on Approach to Work-Up and Diagnosis

Neuromyelitis Optica Spectrum Disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) primarily affecting the optic nerves and spinal cord, but also involving other regions of the CNS including the area postrema, periaqueductal gray matter, and hypothalamus. Knowledge related to pediatric manifestations of NMOSD has grown in recent years, particularly in light of newer information regarding the importance of not only antibodies to aquaporin 4 (AQP4-IgG) but also myelin oligodendrocyte glycoprotein (MOG-IgG) in children manifesting clinically with this syndrome. In this review, we describe the current state of the knowledge related to clinical manifestations, diagnosis, and chronic therapies for children with NMOSD, with emphasis on literature that has been published in the last 5 years. Following the review, we propose recommendations for the assessment/follow up clinical care, and treatment of this population.

Monoclonal Antibody Therapies for Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

Considerable progress has been made in treatments for multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) over the last several decades. However, the present treatments do not show satisfactory efficacy or safety in a considerable proportion of patients, who experience relapse or disability progression despite receiving treatment and suffer from side effects, which can be severe. Improvements in the understanding of the pathophysiologies of MS and NMOSD have led to numerous therapeutic approaches being proposed and developed. Monoclonal antibodies (mAbs) are receiving increasing attention because of their specificity of action and likelihood of high efficacy with fewer side effects. Many mAbs have been evaluated, and some have been approved for MS or NMOSD treatment. This article reviews the use of mAbs for treating MS and NMOSD, including summarizing their mechanisms of action, efficacy, and safety profiles.

The Balance in T Follicular Helper Cell Subsets Is Altered in Neuromyelitis Optica Spectrum Disorder Patients and Restored by Rituximab

Neuromyelitis optica spectrum disorder (NMOSD) is a rare and severe auto-immune disease of the central nervous system driven by pathogenic antibodies mainly directed against aquaporin-4 (AQP4-Ab). Treatment of NMOSD currently relies on immunosuppressants (mycophenolate mofetil, azathioprine) or B-cell-depleting therapy (rituximab). B-cell differentiation into antibody-producing cells requires T follicular helper cells (Tfh). There are several Tfh subsets that differentially affect B-cell differentiation; Tfh2 and Tfh17 subsets strongly support B-cell differentiation. By contrast, Tfh1 lack this capacity and T follicular regulatory cells (Tfr), inhibit B-cell differentiation into antibody-producing cells. We performed a broad characterization of circulating Tfh subsets in 25 NMOSD patients and analyzed the impact of different treatments on these subsets. Untreated NMOSD patients presented a Tfh polarization toward excessive B-helper Tfh subsets with an increase of Tfh17 and (Tfh2+Tfh17)/Tfh1 ratio and a decrease of Tfr and Tfh1. Rituximab restored the Tfh polarization to that of healthy controls. There was a trend toward a similar result for azathioprine and mycophenolate mofetil. Our results suggest that NMOSD patients present an impaired balance in Tfh subsets favoring B-cell differentiation which may explain the sustained antibody production. These findings provide new insights into the pathophysiology of NMOSD, and further suggest that Tfh and Tfr subsets could be considered as potential therapeutic target in NMOSD because of their upstream role in antibody production.

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.

Rituximab treatment for multiple sclerosis

Rituximab, a chimeric anti-CD20-antibody, attracts increasing attention as a treatment option for multiple sclerosis (MS). Apart from smaller controlled trials, an increasing number of studies in real-world populations indicate high efficacy based on clinical and neuroradiological outcomes for rituximab in relapsing-remitting MS patients. Additional evidence also demonstrates efficacy of rituximab with treatment of progressive MS phenotypes. In this topical review, we summarize and discuss current evidence on mechanisms of action, efficacy, safety, tolerance and other clinical aspects of rituximab in the treatment of MS. Finally, we will highlight current knowledge gaps and the need for comparative studies with other disease-modifying therapies in MS.

Cognitive Impairment in Neuromyelitis Optica Spectrum Disorders: A Review of Clinical and Neuroradiological Features

Neuromyelitis optica spectrum disorders (NMOSD) are mostly relapsing autoimmune inflammatory disorders of the central nervous system (CNS) with optic neuritis, myelitis, and brainstem syndromes as clinical hallmarks. With a reported prevalence of up to 70%, cognitive impairment is frequent, but often unrecognized and an insufficiently treated burden of the disease. The most common cognitive dysfunctions are decline in attention and memory performance. Magnetic resonance imaging can be used to access structural correlates of neuropsychological disorders. Cognitive impairment is not only a highly underestimated symptom in patients with NMOSD, but potentially also a clinical correlate of attack-independent changes in NMOSD, which are currently under debate. This article reviews cognitive impairment in NMOSD and discusses associations between structural changes of the CNS and cognitive deficits.

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.

Long-term tolerability, safety and efficacy of rituximab in neuromyelitis optica spectrum disorder: a prospective study

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a B-cell-mediated disease with autoimmunity towards the astrocyte water channel aquaporin-4 (AQP-4) in the central nervous system.

OBJECTIVE

To assess the long-term safety and efficacy in NMOSD patients receiving maintenance therapy with B-cell-depleting agent rituximab for more than 2 years.

METHOD

NMOSD patients were included prospectively from 2014 to 2018 and received continuous cycles of rituximab infusions biannually. Incidence of adverse events (AE), serious AEs (SAE), and infusion-related AEs were evaluated through monthly phone calls and neurological examination every 4 months.

RESULTS

A total of 44 NMOSD patients were included, of those 30 were treatment naive (68%). The mean age was 37.2 years with 79.5% females. With overall observation period of 31.6 ± 7.3 months (24-48 months), tolerability was assessed as satisfactory in most cases. We observed infusion reactions (mostly mild) in 31.8% of patients and 31.8% never experienced any AEs after a mean 5.1 cycles of rituximab therapy. Rituximab was also beneficial in terms of improvement in relapse rate (from 0.26 ± 0.54 to 0, P = 0.003) and Expanded Disability Status Scale (from 4.1 ± 1.8 to 3.1 ± 1.8, P < 0.001). Stratification according to AQP4-IgG serostatus showed no difference between groups.

CONCLUSION

Rituximab treatment is well tolerated, safe, and efficacious with a minor risk of mild infusion reactions for NMOSD patients.

Ozanimod for the treatment of relapsing remitting multiple sclerosis

INTRODUCTION

Ozanimod is a selective sphingosine 1-phosphate receptor 1 and 5 modulator under development by Celgene, for the treatment of relapsing remitting multiple sclerosis. Extensive clinical experience has become available for the related compound fingolimod, favoring the sphingosine 1-phosphate therapeutic concept. Off-target effects have been attributed to its low receptor specificity and have prompted the development of next generation sphingosine 1-phosphate receptor modulators. Areas covered: The authors evaluate the literature of ozanimod, using the PubMed database as well as repositories of the European Committee for Treatment and Research in Multiple Sclerosis and the American and European Academy of Neurology. Specifically, the authors cover and discuss the preclinical data on ozanimod, pharmacokinetics and dynamics, and data on efficacy and safety from the pivotal trials. Expert opinion: Superiority of ozanimod over intramuscular interferon β-1a with regard to reduction in annualized relapse rate and magnetic resonance imaging outcomes has been shown in two phase III trials. The beneficial effect on brain volume and gray matter loss are encouraging and in line with data on other newer immunomodulators. Ozanimod is a valuable contribution to the therapeutic armamentarium in MS, although the effect on disability progression is unclear and requires further investigations.

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.