Faculty Bibliography

BACKGROUND:Fatigue is a common problem experienced by people with multiple sclerosis (PwMS) and can impact physical, cognitive, and psychosocial aspects of daily living and quality of life. The tracking of meaningful longitudinal change in subjective fatigue that occurs as a result of MS activity may be enhanced by incorporating objective neurophysiological measures into longitudinal assessment. To examine this possibility, we examined the longitudinal relationship between visual evoked potential (VEP) measures and a variety of fatigue measures over an approximately two-year period in PwMS. METHODS:VEP measures were obtained using a checkerboard pattern-reversal paradigm. Fatigue was assessed with the Modified Fatigue Impact Scale (MFIS Global, Physical, Cognitive, and Psychosocial subscales) and the Fatigue Severity Scale (FSS) questionnaires. Multiple linear regression analyses were conducted in which the change in each fatigue scale score from baseline to follow-up (T1-to-T2) served as the outcome variables for separate models. Predictor variables included the peak latency of the P100 component of the VEP (maximum peak among the two eyes) and the inter-ocular latency (IOL) at T1, the T1-to-T2 change score for maximum VEP latency and IOL, and the fatigue score at T1 that corresponded to each outcome measure. RESULTS:Prolonged baseline VEP latency was a significant predictor of the T1-to-T2 increase in MFIS Global score, and increased VEP latency from baseline to follow-up was significantly associated with MFIS Cognitive score over the same time period. Furthermore, VEP latency measures in these two models were better predictors of changes in fatigue than baseline fatigue scores were, based on the magnitude of the standardized beta coefficients. Subsequent post-hoc analyses revealed that the relationship between change in VEP latency and change in MFIS Cognitive score was evident primarily for PwMS that had elevated MFIS Cognitive score at baseline. CONCLUSION/CONCLUSIONS:The present study provides novel evidence that prolonged VEP latency is predictive of worsening of global and cognitive fatigue in PwMS. VEP latency measures may therefore provide clinical utility for monitoring changes in fatigue in PwMS, when used in conjunction with other clinical tools.

BACKGROUND:Infections in people with multiple sclerosis (PwMS) may have a detrimental effect on disease progression, risk of hospitalization, and healthcare resource utilization (HRU). The infection risk and HRU costs may vary between disease-modifying therapies (DMTs); however, the individual risks and differences associated with DMTs are not well characterized. Some DMTs may increase the risk for infections in PwMS; however, previous studies have reported an intact humoral immune response in dimethyl fumarate (DMF)-treated patients. The objective was to compare infection-related HRU and healthcare costs (HCCs) between PwMS treated with DMF or ocrelizumab (OCR). METHODS:Eligible patients were identified from the Optum US claims database between April 2017 and September 2020 (DMF n = 1429; OCR n = 3170). Patients were followed from index date to first occurrence of: (1) end of study, (2) end of insurance eligibility, (3) discontinuation of index DMT, or (4) switch from index DMT to another DMT. Outcomes were annualized rate of infection encounters (defined as infection encounters [n] during follow-up window / days followed [n] × 365); annualized infection-related HCCs (defined as aggregated costs of infection encounters during follow-up window / days followed [n] × 365); location-specific infections, and overall infection-related events. Propensity score matching (PSM) 1:1 method was used; PS was calculated via logistic regression for probability of DMF treatment conditional on demographics and comorbidities. Mean differences (MD) were reported for infection encounter measures. RESULTS:After PSM, DMF and OCR cohorts (n = 1094 in each cohort) were balanced based on baseline characteristics (standardized MD of adjusted baseline characteristics <0.1). Mean (standard deviation) follow-up was 296 (244) days for DMF patients and 297 (243) for OCR patients. DMF patients experienced lower annualized rates of overall infection encounters vs OCR patients (MD -0.51 [95% confidence interval (CI): -0.92 to -0.11], p = 0.01). When stratified by type of infection encounter, DMF patients experienced significantly lower annualized rates of outpatient (MD [95% CI]: -0.44 [-0.80 to -0.08], p = 0.02) and inpatient/hospitalization infection encounters (-0.08 [-0.14 to -0.02], p<0.01) vs OCR patients. A trend towards a shorter duration of infection-related hospitalization in the DMF vs the OCR group was observed (MD [95% CI]: -2.20 [-4.73 to 0.26] days, p = 0.08). The most common infection types in both DMT groups were urinary tract infections, sepsis, and pneumonia. DMF patients experienced lower annualized infection-related HCCs (MD [95% CI]: -$3642 [-$6380 to -$904], p < 0.01) vs OCR patients, which were driven largely by infection-related hospitalization costs (-$3639 [-$6019 to -$1259], p < 0.01). CONCLUSION/CONCLUSIONS:DMF-treated patients PS-matched with OCR patients experienced lower annualized rates of infection encounters and lower infection-related HCCs.

INTRODUCTION:Diroximel fumarate (DRF) is an oral fumarate for relapsing multiple sclerosis (MS). Clinical and real-world studies of DRF have demonstrated improved gastrointestinal (GI) tolerability and low (< 1%) GI-related treatment discontinuation versus dimethyl fumarate (DMF) and high rates of treatment adherence. Our aim was to conduct a concept elicitation study to identify treatment-related concepts most meaningful to patients and to evaluate how these concepts shape the patient perspective of DRF. METHODS:In-depth qualitative interviews were conducted with patients from October to December 2020. US adults who had been prescribed DRF through routine clinical care and had taken DRF for ≥ 3 weeks in the past 6 months were eligible to participate. Semi-structured interviews explored patient perceptions on treatment selection and impact. RESULTS:Seventeen patients participated in the study. Mean (SD) age was 49.3 (12.0) years. Sixteen patients reported prior disease-modifying therapy, while 10 (58.8%) had prior DMF. DRF treatment duration ranged from ~ 6 weeks to 10 months. Four key concepts emerged: (1) overall wellness and quality of life, (2) ease of administration, (3) minimal and manageable side effects, and (4) patient optimism due to MS treatments. Mode of administration (82.4%), no/mild side effects (70.6%), convenience over injectable/infusion medications (58.8%), and effectiveness (64.7%) were cited as positive aspects of DRF treatment. Frequent dosing (52.9%) and food requirements (41.2%) were cited as negative attributes; however, 94.1% had no dietary changes since starting treatment. CONCLUSION:The patient perspective is a key aspect when considering a disease-modifying therapy for MS, given the multitude of options currently available. Overall wellness, ease of administration, and minimal and manageable side effects were DRF-related concepts most meaningful to patients on therapy. Acknowledging these patient perceptions in shared decision-making may lead to greater patient adherence and optimal treatment outcomes.

OBJECTIVE:Visual evoked potentials (VEPs) can provide insight into disease activity in people with multiple sclerosis (PwMS). However, few studies have tracked concurrent changes in VEPs and cognitive functioning over time in MS. To address this, we examined the longitudinal relationship between VEP and cognitive performance in PwMS over a two-year period. METHODS:At baseline (T1) and follow-up (T2, 2.14 years after baseline, on average), P100 peak latency and inter-ocular latency (IOL) between eyes were calculated from the VEP elicited for checkerboard pattern-reversal stimuli. Cognitive performance was assessed for seven different domains (NeuroTrax battery). The potential for VEP variables to predict the T1-to-T2 change in cognitive performance was assessed in a series of multiple linear regression models. RESULTS:Baseline IOL and VEP latency were significantly associated with T1-to-T2 change in information processing speed. Post-hoc analyses indicated that PwMS that had both prolonged VEP latency and elevated IOL at baseline tended to exhibit greater information processing speed decline. Increase in VEP latency from T1-to-T2 was also associated with decline in psychomotor function over time. CONCLUSIONS:These findings provide evidence that VEP measures can serve as valuable prognostic indicators of longitudinal cognitive change in PwMS. SIGNIFICANCE:Visual system neurophysiology corresponds with changes in speeded cognitive performance in MS.

OBJECTIVE:Multiple sclerosis (MS) is a debilitating neurological disease associated with a variety of psychological, cognitive, and motoric symptoms. Walking is among the most important functions compromised by MS. Dual-task walking (DTW), an everyday activity in which people walk and engage in a concurrent, discrete task, has been assessed in MS, but little is known about how it relates to other MS symptoms. Self-awareness theory suggests that DTW may be a function of the interactions among psychological, cognitive, and motor processes. METHOD/METHODS:Cognitive testing, self-report assessments for depression and falls self-efficacy (FSE), and walk evaluations [DTW and single-task walk (STW)] were assessed in seventy-three people with MS in a clinical care setting. Specifically, we assessed whether psychological factors (depression and FSE) that alter subjective evaluations regarding one's abilities would moderate the relationships between physical and cognitive abilities and DTW performance. RESULTS:DTW speed is related to diverse physical and cognitive predictors. In support of self-awareness theory, FSE moderated the relationship between STW and DTW speeds such that lower FSE attenuated the strength of the relationship between them. DTW costs - the change in speed normalized by STW speed - did not relate to cognitive and motor predictors. DTW costs did relate to depressive symptoms, and depressive symptoms moderated the effect of information processing on DTW costs. CONCLUSIONS:Findings indicate that an interplay of physical ability and psychological factors - like depression and FSE - may enhance understanding of walking performance under complex, real-world, DTW contexts.

INTRODUCTION:Diroximel fumarate (DRF) is an oral fumarate for relapsing multiple sclerosis (MS) with the same active metabolite as dimethyl fumarate (DMF). DRF has a safety/efficacy profile similar to DMF but with improved gastrointestinal (GI) tolerability and low (< 1%) treatment discontinuation due to GI adverse events (AEs). Efficacy and safety outcomes in patients who switched to DRF from other disease-modifying therapies (DMTs) have not been evaluated. METHODS:EVOLVE-MS-1 is an ongoing, 2-year, open-label, phase 3 study of DRF in adults with relapsing-remitting MS. Patients either entered as newly enrolled to DRF trials, or from the 5-week, randomized, head-to-head, phase 3 EVOLVE-MS-2 study of DRF and DMF. This analysis evaluated safety and GI tolerability in patients continuing on DRF (DRF-rollover) or switching from DMF (DMF-rollover) following EVOLVE-MS-2. Safety and efficacy were evaluated in a subset of newly enrolled patients who had received prior glatiramer acetate (GA; GA/DRF) or interferons (IFN; IFN/DRF) as their most recent DMT, prior to switching to DRF in EVOLVE-MS-1. RESULTS:As of September 1, 2020, 1057 patients were enrolled in EVOLVE-MS-1, including 166, 182, 239, and 225 patients in the GA/DRF, IFN/DRF, DRF-rollover, and DMF-rollover groups, respectively. Treatment discontinuation due to GI AEs was < 1% in all groups. GA/DRF and IFN/DRF patients experienced improvements from baseline in clinical and radiological efficacy outcomes, including significantly reduced annualized relapse rates. Rollover patients had low rates of new or recurrent GI AEs (DRF-rollover, 26.8%/4.2%; DMF-rollover, 27.1%/4.9%). CONCLUSION:After 2 years of DRF exposure, patients with prior GA, IFN, or fumarate treatment had safety outcomes consistent with previous fumarate studies. Efficacy in patients with prior GA or IFN treatment was consistent with previous fumarate studies. The data suggest that transition to DRF from GA, IFN, or DMF is a reasonable treatment strategy, with low rates of discontinuation due to GI AEs. TRIAL REGISTRATION:ClinicalTrials.gov (NCT02634307). INFOGRAPHIC.

BACKGROUND:The Symbol Digit Modalities Test (SDMT) is a common screen of cognitive function for people with Multiple Sclerosis (pwMS) but growing acknowledgement that people with cognitive impairment are a heterogeneous population suggests that a single screen may provide limited information. OBJECTIVE:To assess the adequacy of the SDMT in capturing impairment across specific cognitive domains as measured by a multi-domain cognitive assessment battery (CAB, NeuroTrax). METHODS:113 pwMS were assessed with SDMT and the CAB. Cognitive impairment in each CAB domain was defined as ≥1.5 SD below the normalized mean. Logistic regression models were fit for each CAB domain with domain-specific cognitive impairment as the outcome and SDMT as the predictor, and a classifier created by selecting cutpoints using the Youden Index. Model performance was assessed by predicting domain-specific cognitive impairment in an independent data set consisting of 81 pwMS. RESULTS:SDMT was a significant predictor of cognitive impairment in all outcomes considered (Odds Ratio: 0.885-0.950), but prediction metrics such as area under the receiver operating curve (AUC) were modest (0.623-0.778), and the alignment between observed/predicted impairment was less than optimal. CONCLUSION/CONCLUSIONS:The SDMT is not sufficient to differentiate between impaired and non-impaired pwMS across several cognitive domains.

BACKGROUND:The Expanded Disability Status Scale (EDSS) is widely utilized in clinical trials and routine care to evaluate disease burden and progression among people with multiple sclerosis (pwMS). However, instrumental gait measures may be more suitable than EDSS to track walking disability in pwMS. In this cross-sectional study, we aimed to quantify the variability of spatiotemporal gait measures within homologous EDSS categories. METHODS:A total of 205 pwMS (age=46.5[SD=10.5] years, 72.2% female, EDSS range=1.0-6.5) were studied in this retrospective analysis. Participants underwent walking assessments through the GAITRite system and the following spatiotemporal gait measures were recorded: gait speed, mean normalized velocity (MNV), base of support, stride length, step length, percentage of gait cycle spent in double support and single support, and functional ambulation profile. The EDSS was evaluated by a certified neurologist. RESULTS:≤0.17). Overall, the percent variability of gait measures increased across EDSS categories, with coefficients of variation ranging from 6.9% to 37.2% in the minimal disability group (EDSS≤2.5), 8.1% to 33.4% and 22.3% to 53.8% in the moderate (2.5<EDSS≤4.5) and severe (EDSS>4.5) disability groups, respectively. CONCLUSION/CONCLUSIONS:Spatiotemporal gait measures have great variability within homologous EDSS categories. The high percent variability of gait speed and MNV (up to more than 50%) suggests that walking ability varies substantially within and across disability levels. Therefore, in addition to the EDSS, more comprehensive (multidimensional), objective patient-centric metrics would be needed to accurately evaluate disability in pwMS.

BACKGROUND:Fatigue in people with multiple sclerosis (PwMS) can impact physical, cognitive, and psychosocial domains of daily life. The experience of fatigue in PwMS is thought to originate from the central nervous system, particularly for the domain of cognitive fatigue. Here, we tested the hypothesis that fatigue scores in PwMS would be significantly associated with an index of neural activity - the latency of the P100 of the visual evoked potential (VEP) - in line with the notion of a centralized origin of fatigue. We predicted that prolonged VEP latency would be associated with greater fatigue, and that this relationship would be the most pronounced within the domain of cognitive fatigue. METHODS:PwMS (n=249) completed the Modified Fatigue Impact Scale (Global, Physical, Cognitive, and Psychosocial scales of the MFIS) and Fatigue Severity Scale. VEP latency was obtained using an alternating checkerboard paradigm. We also examined the influence of depression (Beck Depression Inventory, second edition, BDI-II) and cognitive functioning (NeuroTrax testing battery) on the VEP/fatigue relationship. RESULTS:Surprisingly, we observed that earlier (not later) VEP latency was significantly associated with higher MFIS Cognitive score. The negative relationship between VEP latency and cognitive fatigue was evident in PwMS that had poor cognitive performance as measured by a latent variable that reflected attention, executive function, information processing speed, and motor skills; but a significant relationship was not observed in PwMS that exhibited good performance on this measure. CONCLUSIONS:These findings can be interpreted within a metacognitive framework - greater fatigue may be perceived when neural performance and the level of mental effort expended does not translate to efficient cognitive performance. Cognitive fatigue may be particularly salient in PwMS when neural resources are unable to compensate for cognitive difficulties. The mismatch between the expectation of what ought to occur and what does occur during cognitive performance may be a key feature of the experience of cognitive fatigue for some PwMS.