Efficacy and safety of satralizumab monotherapy for relapse prevention in neuromyelitis optica spectrum disorder (NMOSD): Results from SAkuraStar, a double-blind placebo-controlled phase 3 clinical study

Neuromyelitis optica spectrum disorder: do patients positive and negative for anti-aquaporin-4 antibodies present distinct entities? A Colombian perspective

INTRODUCTION

Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system characterised by attacks of optic neuritis and longitudinally extensive transverse myelitis. The discovery of anti-aquaporin-4 (anti-AQP4) antibodies and specific brain MRI findings as diagnostic biomarkers have enabled the recognition of a broader and more detailed clinical phenotype, known as neuromyelitis optica spectrum disorder (NMOSD).

OBJECTIVE

This study aimed to determine the demographic and clinical characteristics of patients with NMO/NMOSD with and without seropositivity for anti-AQP4 antibodies, in 2 quaternary-level hospitals in Bogotá.

METHODS

Our study included patients > 18 years of age and diagnosed with NMO/NMOSD and for whom imaging and serology results were available, assessed between 2013 and 2017 at the neurology departments of hospitals providing highly complex care. Demographic, clinical, and imaging data were gathered and compared in patients with and without seropositivity for anti-AQP4 antibodies.

RESULTS

The sample included 35 patients with NMO/NMOSD; the median age of onset was 46.5 years (P25-P75, 34.2-54.0); most patients had sensory (n = 25) and motor manifestations (n = 26), and a concomitant autoimmune disease was identified in 6. Twenty patients were seropositive for anti-AQP4 antibodies. Only age and presence of optic nerve involvement showed statistically significant differences between groups (P = .03).

CONCLUSIONS

Clinical, imaging, and laboratory variables showed no major differences between patients with and without anti-AQP4 antibodies, with the exception of age of onset and presence of optic nerve involvement (uni- or bilateral); these factors should be studied in greater detail in larger populations.

Next generation antibody-based therapies in neurology

Antibody (Ab)-based therapeutics are now standard in the treatment of neuroinflammatory diseases, and the spectrum of neurological diseases targeted by those approaches continues to grow. The efficacy of Ab-based drug-platforms is largely determined by the specificity-conferring antigen-binding fragment (Fab) and the crystallizable fragment (Fc) driving antibody function. The latter provides specific instructions to the immune system by interacting with cellular Fc receptors and complement components. Extensive engineering efforts enabled tuning of Fc functions to modulate effector functions and to prolong or reduce Ab serum half-lives. Technologies that improve bioavailability of Ab-based treatment platforms within the central nervous system parenchyma are being developed and could invigorate drug discovery for a number of brain diseases for which current therapeutic options are limited. These powerful approaches are currently being tested in clinical trials or have been successfully translated into the clinic. Here, we review recent developments in the design and implementation of Ab-based treatment modalities in neurological diseases.

Interleukin-6 inhibition with tocilizumab for relapsing MOG-IgG associated disorder (MOGAD): A case-series and review

BACKGROUND

Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) associated disorder (MOGAD) is a CNS demyelinating disease distinct from neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis. Some patients with MOGAD exhibit a highly-relapsing and steroid-dependent disease course for which optimal treatment is unknown. Interleukin-6 (IL-6) plays an important pathobiologic role in NMOSD with aquaporin-4 antibodies and preliminary data suggest similar mechanisms of CNS damage may occur in MOGAD.

OBJECTIVE

To summarize our experience with and all current literature on the use of tocilizumab, an IL-6 inhibitor, for highly-relapsing MOGAD along with the underlying immunopathologic rationale.

METHODS

This is a single-center report from a U.S. military tertiary referral hospital of all patients with clinically, radiographically, and serologically confirmed MOGAD who were treated with tocilizumab compiled with data from five other case series/reports from tertiary referral centers. The main outcomes of interest were reduction in annualized relapse rate and required dose of oral prednisone for symptomatic management.

RESULTS

Ten total patients with relapsing MOGAD who were treated with intravenous or subcutaneous tocilizumab were identified. At our institution, a 20 year-old female with a 9-year history of highly-relapsing and steroid dependent MOGAD was treated with tocilizumab. In 28 months of follow up, she had no clinical relapses and was able to discontinue corticosteroids. Another 35 year-old female at our institution with a 10-year history of highly-relapsing and steroid dependent MOGAD was treated with tocilizumab for 6 months. Tocilizumab therapy was associated with relapse freedom, resolution of eye pain, and ability to discontinue corticosteroids. When compiled with data from all other case reports of relapsing MOGAD treated with tocilizumab, there have been zero clinical or radiographic relapses in 10 patients over an average treatment duration of 28.6 months.

CONCLUSIONS

Tocilizumab is an IL-6 inhibitor that may be a promising therapeutic option for patients with relapsing MOGAD that has not responded to other immunotherapies. Our results support a key role for IL-6-related mechanisms in MOGAD disease activity. Its safety and tolerability profile, both in our own experience and based on its use for other FDA approved conditions, may even justify its use a first line therapy in select patients. Further research is needed to establish the safety and efficacy of IL-6 inhibition in MOGAD.

Targeting IL-6 receptor in the treatment of neuromyelitis optica spectrum: a review of emerging treatment options

Introduction: Recent research has shown that IL-6 receptor (IL-6 R) inhibitors like tocilizumab and satralizumab are effective in reducing the relapse rate in patients with NMOSD.Areas covered: This review article explores current concepts in NMOSD management and focuses on IL-6 R as a therapeutic target. The authors delve into the biological and immunological role of IL-6 in the pathogenesis of NMOSD. Further, the authors summarize the most recent findings on the use of anti-IL-6 R monoclonal antibodies, tocilizumab and satralizumab, in the treatment of NMOSD.Expert opinion: A better understanding of the role of cytokines in NMOSD may provide the neurologist with novel therapies for this disease. IL-6 R appears to be a central hub to NMOSD pathogenesis and a relevant therapeutic target.