Faculty Bibliography

BACKGROUND AND PURPOSE: Characterization of iron deposition associated with demyelinating lesions of multiple sclerosis and neuromyelitis optica has not been well studied. Our aim was to investigate the potential of ultra-high-field MR imaging to distinguish MS from neuromyelitis optica and to characterize tissue injury associated with iron pathology within lesions. MATERIALS AND METHODS: Twenty-one patients with MS and 21 patients with neuromyelitis optica underwent 7T high-resolution 2D-gradient-echo-T2* and 3D-susceptibility-weighted imaging. An in-house-developed algorithm was used to reconstruct quantitative susceptibility mapping from SWI. Lesions were classified as "iron-laden" if they demonstrated hypointensity on gradient-echo-T2*-weighted images and/or SWI and hyperintensity on quantitative susceptibility mapping. Lesions were considered "non-iron-laden" if they were hyperintense on gradient-echo-T2* and isointense or hyperintense on quantitative susceptibility mapping. RESULTS: Of 21 patients with MS, 19 (90.5%) demonstrated at least 1 quantitative susceptibility mapping-hyperintense lesion, and 11/21 (52.4%) had iron-laden lesions. No quantitative susceptibility mapping-hyperintense or iron-laden lesions were observed in any patients with neuromyelitis optica. Iron-laden and non-iron-laden lesions could each be further characterized into 2 distinct patterns based on lesion signal and morphology on gradient-echo-T2*/SWI and quantitative susceptibility mapping. In MS, most lesions (n = 262, 75.9% of all lesions) were hyperintense on gradient-echo T2* and isointense on quantitative susceptibility mapping (pattern A), while a small minority (n = 26, 7.5% of all lesions) were hyperintense on both gradient-echo-T2* and quantitative susceptibility mapping (pattern B). Iron-laden lesions (n = 57, 16.5% of all lesions) were further classified as nodular (n = 22, 6.4%, pattern C) or ringlike (n = 35, 10.1%, pattern D). CONCLUSIONS: Ultra-high-field MR imaging may be useful in distinguishing MS from neuromyelitis optica. Different patterns related to iron and noniron pathology may provide in vivo insight into the pathophysiology of lesions in MS.

BACKGROUND: Natalizumab (NTZ), a monoclonal antibody to human alpha4beta1/beta7 integrin, is an effective therapy for multiple sclerosis (MS), albeit associated with progressive multifocal leukoencephalopathy (PML). Clinicians have been extending the dose of infusions with a hypothesis of reducing PML risk. The aim of the study is to evaluate the clinical consequences of reducing NTZ frequency of infusion up to 8 weeks 5 days. METHODS: A retrospective chart review in 9 MS centres was performed in order to identify patients treated with extended interval dosing (EID) regimens of NTZ. Patients were stratified into 3 groups based on EID NTZ treatment schedule in individual centres: early extended dosing (EED; n=249) every 4 weeks 3 days to 6 weeks 6 days; late extended dosing (LED; n=274) every 7 weeks to 8 weeks 5 days; variable extended dosing (n=382) alternating between EED and LED. These groups were compared with patients on standard interval dosing (SID; n=1093) every 4 weeks. RESULTS: 17% of patients on SID had new T2 lesions compared with 14% in EID (p=0.02); 7% of patients had enhancing T1 lesions in SID compared with 9% in EID (p=0.08); annualised relapse rate was 0.14 in the SID group, and 0.09 in the EID group. No evidence of clinical or radiographic disease activity was observed in 62% of SID and 61% of EID patients (p=0.83). No cases of PML were observed in EID group compared with 4 cases in SID cohort. CONCLUSIONS: Dosing intervals up to 8 weeks 5 days did not diminish effectiveness of NTZ therapy. Further monitoring is ongoing to evaluate if the risk of PML is reduced in patients on EID.

OBJECTIVE: We aimed to analyse the effect of the introduction of fingolimod, the first oral disease-modifying therapy, on treatment utilisation and persistence in an international cohort of patients with multiple sclerosis (MS). METHODS: MSBASIS, a prospective, observational sub-study of the MSBase registry, collects demographic, clinical and paraclinical data on patients followed from MS onset (n=4718). We conducted a multivariable conditional risk set survival analysis to identify predictors of treatment discontinuation, and to assess if the introduction of fingolimod has altered treatment persistence. RESULTS: A total of 2640 patients commenced immunomodulatory therapy. Following the introduction of fingolimod, patients were more likely to discontinue all other treatments (hazard ratio 1.64, p<0.001) while more patients switched to fingolimod than any other therapy (42.3% of switches). Patients switched to fingolimod due to convenience. Patients treated with fingolimod were less likely to discontinue treatment compared with other therapies (p<0.001). Female sex, country of residence, younger age, a high Expanded Disability Status Scale score and relapse activity were all independently associated with higher rates of treatment discontinuation. CONCLUSION: Following the availability of fingolimod, patients were more likely to discontinue injectable treatments. Those who switched to fingolimod were more likely to do so for convenience. Persistence was improved on fingolimod compared to other medications.

Limited data suggest that multiple sclerosis (MS) in Latin America (LA) could be less severe than in the rest of the world. The objective was to compare the course of MS between LA and other regions. METHODS: Centers from 18 countries with >20 cases enrolled in the MSBase Registry participated. Patients with MS with a disease duration of >1 year and <30 years at time of EDSS measurement were evaluated. The MS Severity Score (MSSS) was used as a measure of disease progression. Comparisons among regions (North America, Europe, Australia and LA), hemispheres and countries were performed. RESULTS: A total of 9610 patients were included. Patients were from: Europe, 6290 (65.6%); North America, 1609 (16.7%); Australia, 1119 (11.6%); and LA, 592 (6.1%). The mean MSSS in patients from LA was 4.47 +/- 2.8, 4.53 +/- 2.8 in North America, 4.51 +/- 2.8 in Europe and 4.49 +/- 2.7 in Australia. Mean MSSS in the northern hemisphere was 4.51 +/- 1.6 compared to 4.48 +/- 1.9 in the southern hemisphere. No differences were found for MSSS among hemispheres (p = 0.68), regions (p = 0.96) or countries (p = 0.50). CONCLUSIONS: Our analyses did not discover any difference in mean MSSS among patients from different regions, hemispheres or countries.

BACKGROUND: Growing evidence suggests an association between adolescent obesity and increased risk of multiple sclerosis (MS). OBJECTIVE: The objective of this paper is to investigate whether weight or body mass index (BMI) in adolescence and young adulthood was associated with age at MS symptom onset. METHODS: Our cohort is comprised of a sub-group of 184 women enrolled in the New York State MS Consortium registry. Individuals were asked to recall their weight at the time of first menstruation and at age 25. BMI was calculated accordingly for age 25. Regression analyses were carried out to investigate the association between weight or BMI and age at onset. RESULTS: Weight at menarche was significantly related to younger age at symptom onset (beta = -0.073, p = 0.001). These results were also found at age 25 for weight (beta = -0.080, p < 0.001) and BMI (beta = -0.448, p = 0.001). Significantly earlier disease onset (26.9 years +/-9.9) was observed in individuals who were overweight at 25 compared to those who were not overweight (32.1 years +/-9.2, p = 0.006). CONCLUSIONS: Women who reported higher weight in adolescence and BMI in early adulthood were younger at MS onset. Future research should investigate whether there is a causal link between body weight and MS, as prevention lifestyle and dietary interventions could be implemented.