Comparison of switching to 6-week dosing of natalizumab versus continuing with 4-week dosing in patients with relapsing-remitting multiple sclerosis (NOVA): a randomised, controlled, open-label, phase 3b trial

BACKGROUND

Treatment with natalizumab once every 4 weeks is approved for patients with relapsing-remitting multiple sclerosis, but is associated with a risk of progressive multifocal leukoencephalopathy. Switching to extended-interval dosing is associated with lower progressive multifocal leukoencephalopathy risk, but the efficacy of this approach is unclear. We aimed to assess the safety and efficacy of natalizumab once every 6 weeks compared with once every 4 weeks in patients with relapsing-remitting multiple sclerosis.

METHODS

We did a randomised, controlled, open-label, phase 3b trial (NOVA) at 89 multiple sclerosis centres across 11 countries in the Americas, Europe, and Western Pacific. Included participants were aged 18-60 years with relapsing-remitting multiple sclerosis and had been treated with intravenous natalizumab 300 mg once every 4 weeks with no relapses for at least 12 months before randomisation, with no missed doses in the previous 3 months. Participants were randomly assigned (1:1), using a randomisation sequence generated by the study funder and contract personnel with interactive response technology, to switch to natalizumab once every 6 weeks or continue with once every 4 weeks. The centralised MRI reader, independent neurology evaluation committee, site examining neurologists, site backup examining neurologists, and site examining technicians were masked to study group assignments. The primary endpoint was the number of new or newly enlarging T2 hyperintense lesions at week 72, assessed in all participants who received at least one dose of assigned treatment and had at least one postbaseline MRI, relapse, or neurological examination or efficacy assessment. Missing primary endpoint data were handled under prespecified primary and secondary estimands: the primary estimand included all data, regardless of whether participants remained on the assigned treatment; the secondary estimand classed all data obtained after treatment discontinuation or study withdrawal as missing. Safety was assessed in all participants who received at least one dose of study treatment. Study enrolment is closed and an open-label extension study is ongoing. This study is registered with EudraCT, 2018-002145-11, and ClinicalTrials.gov, NCT03689972.

FINDINGS

Between Dec 26, 2018, and Aug 30, 2019, 605 patients were assessed for eligibility and 499 were enrolled and assigned to receive natalizumab once every 6 weeks (n=251) or once every 4 weeks (n=248). After prespecified adjustments for missing data, mean numbers of new or newly enlarging T2 hyperintense lesions at week 72 were 0·20 (95% CI 0·07-0·63) in the once every 6 weeks group and 0·05 (0·01-0·22) in the once every 4 weeks group (mean lesion ratio 4·24 [95% CI 0·86-20·85]; p=0·076) under the primary estimand, and 0·31 (95% CI 0·12-0·82) and 0·06 (0·01-0·31; mean lesion ratio 4·93 [95% CI 1·05-23·20]; p=0·044) under the secondary estimand. Two participants in the once every 6 weeks group with extreme new or newly enlarging T2 hyperintense lesion numbers (≥25) contributed most of the excess lesions. Adverse events occurred in 194 (78%) of 250 participants in the once every 6 weeks group and 190 (77%) of 247 in the once every 4 weeks group, and serious adverse events occurred in 17 (7%) and 17 (7%), respectively. No deaths were reported. There was one case of asymptomatic progressive multifocal leukoencephalopathy (without clinical signs) in the once every 6 weeks group, and no cases in the once every 4 weeks group; 6 months after diagnosis, the participant was without increased disability and remained classified as asymptomatic.

INTERPRETATION

We found a numerical difference in the mean number of new or newly enlarging T2 hyperintense lesions at week 72 between the once every 6 weeks and once every 4 weeks groups, which reached significance under the secondary estimand, but interpretation of statistical differences (or absence thereof) is limited because disease activity in the once every 4 weeks group was lower than expected. The safety profiles of natalizumab once every 6 weeks and once every 4 weeks were similar. Although this trial was not powered to assess differences in risk of progressive multifocal leukoencephalopathy, the occurrence of the (asymptomatic) case underscores the importance of monitoring and risk factor consideration in all patients receiving natalizumab.

FUNDING

Biogen.

Nerve biopsy: Current indications and decision tools

After initial investigation of patients presenting with symptoms suggestive of neuropathy, a clinical decision is made for a minority of patients to undergo further assessment with nerve biopsy. Many nerve biopsies do not demonstrate a definitive pathological diagnosis and there is considerable cost and morbidity associated with the procedure. This highlights the need for appropriate selection of patients, nerves and neuropathology techniques. Additionally, concomitant muscle and skin biopsies may improve the diagnostic yield in some cases. Several advances have been made in diagnostics in recent years, particularly in genomics. The indications for nerve biopsy have consequently changed over time. This review explores the current indications for nerve biopsies and some of the issues surrounding its use. Also included are comments on alternative diagnostic modalities that may help to supplant or reduce the use of nerve biopsy as a diagnostic test. These primarily include extraneural biopsy and neuroimaging techniques such as magnetic resonance neurography and nerve ultrasound. Finally, we propose an algorithm to assist in deciding when to perform nerve biopsies.

Chronic inflammatory demyelinating polyradiculoneuropathy presenting as predominantly sciatic monomelic neuropathy

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a common yet underdiagnosed cause of potentially treatable chronic sensorimotor neuropathy. The classical form of the disease is characterised by symmetrical weakness in both distal and proximal muscle groups accompanied by sensory dysfunction and diminished tendon reflexes lasting more than 2 months.

Method

The diagnosis of CIDP is supplemented by electrodiagnostic studies and biopsy findings confirming demyelination, in accordance with well-established diagnostic criteria. Atypical presentations of CIDP often pose a diagnostic challenge.

Results

In this paper, we present a case of isolated lower limb involvement due to CIDP to raise awareness of this focal lower limb variant. Of particular, significance is the use of lumbosacral plexus MRI to assist in the diagnosis.

Conclusion

Focal CIDP is an atypical presentation that should be considered in patients presenting with chronic monomelic neuropathy and should be investigated with electrodiagnostic studies, lumbar puncture, nerve biopsy and MRI of the nerve roots and plexuses.

Relapse Patterns in NMOSD: Evidence for Earlier Occurrence of Optic Neuritis and Possible Seasonal Variation

Neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) show overlap in their clinical features. We performed an analysis of relapses with the aim of determining differences between the two conditions. Cases of NMOSD and age- and sex-matched MS controls were collected from across Australia and New Zealand. Demographic and clinical information, including relapse histories, were recorded using a standard questionnaire. There were 75 cases of NMOSD and 101 MS controls. There were 328 relapses in the NMOSD cases and 375 in MS controls. Spinal cord and optic neuritis attacks were the most common relapses in both NMOSD and MS. Optic neuritis (p < 0.001) and area postrema relapses (P = 0.002) were more common in NMOSD and other brainstem attacks were more common in MS (p < 0.001). Prior to age 30 years, attacks of optic neuritis were more common in NMOSD than transverse myelitis. After 30 this pattern was reversed. Relapses in NMOSD were more likely to be treated with acute immunotherapies and were less likely to recover completely. Analysis by month of relapse in NMOSD showed a trend toward reduced risk of relapse in February to April compared to a peak in November to January (P = 0.065). Optic neuritis and transverse myelitis are the most common types of relapse in NMOSD and MS. Optic neuritis tends to occur more frequently in NMOSD prior to the age of 30, with transverse myelitis being more common thereafter. Relapses in NMOSD were more severe. A seasonal bias for relapses in spring-summer may exist in NMOSD.

The clinical profile of NMOSD in Australia and New Zealand

Neuromyelitis optica spectrum disorders (NMOSD) are an inflammation of the central nervous system associated with autoantibodies to aquaporin-4. We have undertaken a clinic-based survey of NMOSD in the Australia and New Zealand populations with the aim of characterising the clinical features and establishing the value of recently revised diagnostic criteria. Cases of possible NMOSD and age and sex-matched controls with multiple sclerosis (MS) were referred from centres across Australia and New Zealand. Cases were classified as NMOSD if they met the 2015 IPND criteria and remained as suspected NMOSD if they did not. Clinical and paraclinical data were compared across the three groups. NMOSD was confirmed in 75 cases and 89 had suspected NMOSD. There were 101 controls with MS. Age at onset, relapse rates and EDSS scores were significantly higher in NMOSD than in MS. Lesions and symptoms referable to the optic nerve were more common in NMOSD whereas brainstem, cerebellar and cerebral lesions were more common in MS. Longitudinally extensive spinal cord lesions were seen in 48/71 (68%) of cases with NMOSD. Elevations of CSF, white cell count and protein were more common in NMOSD. We have confirmed a clinical pattern of NMOSD that has been seen in several geographical regions. We have demonstrated the clinical utility of the current diagnostic criteria. Distinct patterns of disease are evident in NMOSD and MS, but there remains a large number of patients with NMOSD-like features who do not meet the current diagnostic criteria for NMOSD and remain a diagnostic challenge.

Conduction block in immune-mediated neuropathy: paranodopathy versus axonopathy

BACKGROUND AND PURPOSE

Conduction block is a pathognomonic feature of immune-mediated neuropathies. The aim of this study was to advance understanding of pathophysiology and conduction block in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN).

METHODS

A multimodal approach was used, incorporating clinical phenotyping, neurophysiology, immunohistochemistry and structural assessments.

RESULTS

Of 49 CIDP and 14 MMN patients, 25% and 79% had median nerve forearm block, respectively. Clinical scores were similar in CIDP patients with and without block. CIDP patients with median nerve block demonstrated markedly elevated thresholds and greater threshold changes in threshold electrotonus, whilst those without did not differ from healthy controls in electrotonus parameters. In contrast, MMN patients exhibited marked increases in superexcitability. Nerve size was similar in both CIDP groups at the site of axonal excitability. However, CIDP patients with block demonstrated more frequent paranodal serum binding to teased rat nerve fibres. In keeping with these findings, mathematical modelling of nerve excitability recordings in CIDP patients with block support the role of paranodal dysfunction and enhanced leakage of current between the node and internode. In contrast, changes in MMN probably resulted from a reduction in ion channel density along axons.

CONCLUSIONS

The underlying pathologies in CIDP and MMN are distinct. Conduction block in CIDP is associated with paranodal dysfunction which may be antibody-mediated in a subset of patients. In contrast, MMN is characterized by channel dysfunction downstream from the site of block.

Anti-MAG neuropathy: Role of IgM antibodies, the paranodal junction and juxtaparanodal potassium channels

OBJECTIVE

To improve understanding of disease pathophysiology in anti-myelin-associated glycoprotein (anti-MAG) neuropathy to guide further treatment approaches.

METHODS

Anti-MAG neuropathy patients underwent clinical assessments, nerve conduction and excitability studies, and ultrasound assessment.

RESULTS

Patients demonstrated a distinctive axonal excitability profile characterised by a reduction in superexcitability [MAG: -14.2 ± 1.6% vs healthy controls (HC): -21.8 ± 1.2%; p < 0.01] without alterations in most other excitability parameters. Mathematical modelling of nerve excitability recordings suggested that changes in axonal function could be explained by a 72.5% increase in juxtaparanodal fast potassium channel activation and an accompanying hyperpolarization of resting membrane potential (by 0.3 mV) resulting in a 94.2% reduction in discrepancy between anti-MAG data and the healthy control model. Superexcitability changes correlated strongly with clinical and neurophysiological parameters. Furthermore, structural assessments demonstrated a proximal pattern of nerve enlargement (C6 nerve root cross-sectional area: 15.9 ± 8.1 mm² vs HC: 9.1 ± 2.3 mm²; p < 0.05).

CONCLUSIONS

The imaging and neurophysiological results support the pathogenicity of anti-MAG IgM. Widening between adjacent loops of paranodal myelin due to antibodies would expand the pathway from the node to the juxtaparanode, increasing activation of juxtaparanodal fast potassium channels, thereby impairing saltatory conduction.

SIGNIFICANCE

Potassium channel blockers may prove beneficial in restoring conduction closer to its normal state and improving nerve function in anti-MAG neuropathy.

004 Mechanisms of nerve dysfunction in inflammatory neuropathies

Introduction

Immune-mediated neuropathies are a cause of disability and an immense cost to the healthcare system. They include chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy (MMN) and the neuropathy associated with IgM antibodies against myelin-associated glycoprotein (MAG). CIDP is extremely heterogeneous with marked variability in treatment responsiveness. Patients with MMN often respond to treatment but progressive weakness and wasting typically ensues over time. No therapy has consistently proven effective in anti-MAG neuropathy. The present series of studies were undertaken to improve understanding of disease mechanisms in these neuropathies, a critical step before targeted treatment approaches can be developed.

Methods

Patients fulfilling Peripheral Nerve Society criteria for CIDP or MMN and patients positive for anti-MAG IgM underwent comprehensive clinical assessments, neurophysiology, serological testing and structural assessments.

Results

The patient cohort consisted of 80 patients (51 CIDP, 14 MMN, 15 MAG). 6% of CIDP patients tested positive for anti-neurofascin 155 (NF155) and 4% for anti-contactin 1 IgG4. Anti-NF155 neuropathy was characterised by diffuse nerve enlargement and an axonal excitability profile consistent with severe disruption of the paranodal seal. CIDP patients testing negative for IgG4 antibodies also demonstrated significant nerve enlargement compared with healthy subjects. Axonal excitability profiles differed in those with and without median nerve conduction block. MMN was characterised by patchy nerve enlargement, marked increases in super-excitability and enlarged motor unit size. In contrast, anti-MAG neuropathy patients demonstrated a proximal pattern of nerve enlargement and an axonal excitability profile characterised by reduced super-excitability consistent with increased juxta-paranodal fast potassium channel conductance.

Conclusion

Patterns of nerve enlargement and neurophysiological profiles differ in the immune-mediated neuropathies providing insights into molecular mechanisms. These results provide templates that can guide treatment approaches. The combination of directed autoantibody assays and measures of axonal function can be used to monitor disease progression and therapeutic response.

015 Predicting a diagnosis of pathologically confirmed vasculitic neuropathy

Introduction

Nerve biopsy remains the gold standard to diagnose vasculitic neuropathy. Conversely, biopsy has imperfect sensitivity and entails risks associated with an invasive procedure. Methods to improve diagnostic accuracy remain important considerations given the severity of the disease, added with the risks associated with subsequent therapy, particularly in ill-defined cases.

Methods

Clinical, laboratory and neurophysiological parameters were analysed for all patients who subsequently underwent biopsy. Nerve and muscle biopsy reports were assigned pathologic categories of definite, probable, possible or absent vasculitis using standard guidelines. Correlations were assessed between pre-biopsy parameters and subsequent diagnosis of definite or probable vasculitic neuropathy (pathologically confirmed vasculitis).

Results

From a cohort of 207 patients who underwent nerve biopsy over 21 months, 70 were suspected of having vasculitic neuropathy prior to biopsy. Of the 70 patients, vasculitis was confirmed as definite (11.4%), probable (15.7%) or possible (10.0%) on neuropathological assessment. The most sensitive parameters for pathologically confirmed vasculitis were the presence of sensorimotor neuropathy (78%) and axonal neuropathy (67%) on nerve conduction studies (NCS) in the overall cohort. Pathologically absent vasculitis was most prevalent in patients with normal NCS (90%), chronic, symmetric symptoms (86%) and demyelinating findings on NCS (79%). The parameters with the strongest associations with pathologically confirmed vasculitis were positive autoantibody serology (50.0% vs 21.1%, p<0.01), anti-neutrophil cytoplasmic antibody (27.3% vs 6.4%, p<0.01), anti-myeloperoxidase antibody (22.7% vs 1.8%, p<0.005) and rheumatoid factor (22.7% vs 2.8%, p<0.005). In patients suspected to have vasculitis, 83.3% of anti-myeloperoxidase antibody positive patients had pathologically confirmed vasculitis. In patients not suspected to have vasculitis, acute symptoms had the strongest association with pathologically confirmed vasculitis (36.4% vs 10.5%, p<0.05).

Conclusion

Specific characteristics of symptoms at the time of presentation, combined with the presence of autoantibodies and neurophysiological abnormalities, were predictive of a tissue diagnosis of vasculitic neuropathy.

Incidence and prevalence of NMOSD in Australia and New Zealand

OBJECTIVES

We have undertaken a clinic-based survey of neuromyelitis optica spectrum disorders (NMOSDs) in Australia and New Zealand to establish incidence and prevalence across the region and in populations of differing ancestry.

BACKGROUND

NMOSD is a recently defined demyelinating disease of the central nervous system (CNS). The incidence and prevalence of NMOSD in Australia and New Zealand has not been established.

METHODS

Centres managing patients with demyelinating disease of the CNS across Australia and New Zealand reported patients with clinical and laboratory features that were suspicious for NMOSD. Testing for aquaporin 4 antibodies was undertaken in all suspected cases. From this group, cases were identified who fulfilled the 2015 Wingerchuk diagnostic criteria for NMOSD. A capture-recapture methodology was used to estimate incidence and prevalence, based on additional laboratory identified cases.

RESULTS

NMOSD was confirmed in 81/170 (48%) cases referred. Capture-recapture analysis gave an adjusted incidence estimate of 0.37 (95% CI 0.35 to 0.39) per million per year and a prevalence estimate for NMOSD of 0.70 (95% CI 0.61 to 0.78) per 100 000. NMOSD was three times more common in the Asian population (1.57 (95% CI 1.15 to 1.98) per 100 000) compared with the remainder of the population (0.57 (95% CI 0.50 to 0.65) per 100 000). The latitudinal gradient evident in multiple sclerosis was not seen in NMOSD.

CONCLUSIONS

NMOSD incidence and prevalence in Australia and New Zealand are comparable with figures from other populations of largely European ancestry. We found NMOSD to be more common in the population with Asian ancestry.

Therapeutic approaches to disease modifying therapy for multiple sclerosis in adults: an Australian and New Zealand perspective: part 1 historical and established therapies. MS Neurology Group of the Australian and New Zealand Association of Neurologists

Multiple sclerosis (MS) is a potentially life-changing immune mediated disease of the central nervous system. Until recently, treatment has been largely confined to acute treatment of relapses, symptomatic therapies and rehabilitation. Through persistent efforts of dedicated physicians and scientists around the globe for 160 years, a number of therapies that have an impact on the long term outcome of the disease have emerged over the past 20 years. In this three part series we review the practicalities, benefits and potential hazards of each of the currently available and emerging treatment options for MS. We pay particular attention to ways of abrogating the risks of these therapies and provide advice on the most appropriate indications for using individual therapies. In Part 1 we review the history of the development of MS therapies and its connection with the underlying immunobiology of the disease. The established therapies for MS are reviewed in detail and their current availability and indications in Australia and New Zealand are summarised. We examine the evidence to support their use in the treatment of MS.

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

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

Gain and loss of gastrointestinal symptoms in diabetes mellitus: associations with psychiatric disease, glycemic control, and autonomic neuropathy over 2 years of follow-up

OBJECTIVE

To prospectively determine the turnover (gain or loss) of gastrointestinal (GI) symptoms in diabetic subjects in relation to glycemic control, autonomic neuropathy and psychiatric disease over a 2-year follow-up.

METHODS

Type 1 and type 2 diabetic subjects were recruited from the community, as were community controls. Individual GI symptoms were examined by a validated questionnaire and classified as diarrhea, irritable bowel syndrome, upper GI symptoms, and any GI symptoms at baseline, 12 and 24 months. Glycemic control (glycated hemoglobin), autonomic function (using standardized tests), and psychiatric disease (using the Composite International Diagnostic Interview) were also assessed at these time points.

RESULTS

Baseline and 2-year follow-up data were available for 139 diabetic subjects and 55 controls. Glycated hemoglobin at baseline was 7.7% (+/-1.36) in the diabetic group; 5% had severe autonomic dysfunction. There was a significantly higher prevalence of diarrhea in the diabetic subjects. GI symptom turnover varied between 15% and 25% in the diabetic group and was not significantly different from the controls. There was no clear association between turnover of GI symptoms and either glycemic control or autonomic neuropathy. The appearance of depression was associated with gaining of most symptoms apart from irritable bowel syndrome, although the associations did not always reach significance. The univariate results were confirmed after adjusting for age, gender, body mass index, and metformin use.

CONCLUSION

The turnover of GI symptoms in diabetic subjects was not associated with glycemic control but there was a positive association with change in depression.

Effect of leflunomide on the peripheral nerves in rheumatoid arthritis

BACKGROUND

The objective of this study was to determine the neurophysiological effects of leflunomide on peripheral nerves in rheumatoid arthritis.

METHODS

We conducted a prospective cohort trial of 32 patients with rheumatoid arthritis with 16 patients receiving leflunomide treatment and 16 receiving other disease-modifying anti-rheumatic drug therapies. Clinical, laboratory and neurophysiological measurements were used to determine the presence of a peripheral neuropathy in these patients at study entry and then after a further 3 and 6 months.

RESULTS

Fifty-four per cent of the leflunomide group and 8% of the control group had an increase in their neuropathy symptom score 6 months into the study (P = 0.01). No correlation was found between the electrophysiological findings and the clinical symptoms. There was no significant difference between the two groups in upper and lower limb sensory and motor amplitudes and conduction velocities recorded at 3 and 6 months. One patient developed both clinical and neurophysiological evidence of a peripheral neuropathy 5 months into the study that improved after cessation of leflunomide therapy and cholestyramine washout.

CONCLUSION

After 6 months of exposure we found that leflunomide was associated with an apparent increase in the clinical symptoms of peripheral neuropathy in patients with rheumatoid arthritis. These symptoms did not correlate with neurophysiological studies.