Blood donation for iron removal in individuals with HFE mutations: study of efficacy and safety and short review on hemochromatosis and blood donation.

Background: Elevated serum ferritin with/without HFE variants in asymptomatic persons leads frequently to referral for blood donation. Hemochromatosis (p.C282Y/p.C282Y) only requires treatment. We evaluated safety and feasibility of iron removal in healthy persons with elevated ferritin and HFE variants using blood donation procedures. Materials and methods: Thirty subjects with ferritin >200 ng/mL (women) or >300 ng/mL (men) with p.C282Y/p.C282Y, p.C282Y/p.H63D or p.H63D/p.H63D were randomized to weekly phlebotomy (removal of 450 mL whole blood) or erythrapheresis (removal of 360 mL red blood cells) every 14 days. The ferritin target was <100 ng/mL. A full blood count and ferritin were measured at each visit. Hemoglobin (Hb) ≥140 g/L was required at inclusion. If Hb dropped to <120 g/L (women) or <130 g/L (men), procedures were postponed (7 or 14 days). Primary endpoint was the number of procedures needed to the ferritin target; secondary objectives were duration of treatment and compliance. The treatment effect was tested with Poisson regression; number of procedures and treatment duration were compared between study arms with the Kruskal-Wallis test. Results: Twenty-five of 30 participants were men (83%); mean age was 47 years (SD 10.5), mean BMI 26.6 kg/m2 (SD 3.6); 17 had p.C282Y/p.C282Y, nine p.C282Y/p.H63D, four p.H63D/p.H63D. Median baseline Hb was 150 g/L (IQR 144, 1,559), median ferritin 504 ng/mL (IQR 406,620). Twenty-seven subjects completed the study. Treatment arm (p < 0.001) and HFE variant (p = 0.007) influenced the primary endpoint significantly. To ferritin levels <100 ng/mL, a median number of 7.5 (IQR 6.2, 9.8) phlebotomies and 4.0 (IQR 3.0, 5.8) erythraphereses (p = 0.001) was needed during a median of 66.5 days (IQR 49,103) and 78.5 days (IQR 46139), respectively (p = 0.448). Low Hb was the principal reason for protocol violation; anemia occurred in 13 participants (48%). Immediate complications were infrequent; fatigue was reported after 25% of phlebotomies and 45% of erythraphereses. Thirty-five procedures were postponed because of low Hb and 15 for non-medical reasons. The median interval was 7.0 (IQR 7.7) and 14.0 (IQR 14, 20) days between phlebotomies and erythraphereses, respectively. Conclusion: Blood donation procedures remove iron effectively in HC, but frequent treatments cause Hb decrease and fatigue that can impair feasibility.

Escalating to medium- versus high-efficacy disease modifying therapy after low-efficacy treatment in relapsing remitting multiple sclerosis.

BACKGROUND: In patients with relapsing remitting multiple sclerosis (RRMS) on low-efficacy disease modifying therapies (DMT), the optimal strategy on how to escalate treatment once needed, remains unknown. METHODS: We studied RRMS patients on low-efficacy DMTs listed in the Swiss National Treatment Registry, who underwent escalation to either medium- or high-efficacy DMTs. Propensity score-based matching was applied using 12 clinically relevant variables. Both groups were also separately matched with control subjects who did not escalate therapy. Time to relapse and to disability worsening were evaluated using Cox proportional hazard models. RESULTS: Of 1037 eligible patients, we 1:1 matched 450 MS patients who switched from low-efficacy to medium-efficacy (n = 225; 76.0% females, aged 42.4 ± 9.9 years [mean ± SD], median EDSS 3.0 [IQR 2-4]) or high-efficacy DMTs (n = 225; 72.4% females, aged 42.2 ± 10.6 years, median EDSS 3.0 [IQR 2-4]). Escalation to high-efficacy DMTs was associated with lower hazards of relapses than medium-efficacy DMTs (HR = 0.67, 95% CI 0.47-0.95, p = .027) or control subjects (HR = 0.61, 95% CI 0.44-0.84, p = .003). By contrast, escalation from low to medium-efficacy DMTs did not alter the hazard for relapses when compared to controls (i.e. patients on low-efficacy DMT who did not escalate DMT during follow-up) CONCLUSION: Our nationwide registry analysis suggests that, once escalation from a low-efficacy DMT is indicated, switching directly to a high-efficacy treatment is superior to a stepwise escalation starting with a moderate-efficacy treatment.

Neurofilaments as biomarkers in neurological disorders - towards clinical application.

Neurofilament proteins have been validated as specific body fluid biomarkers of neuro-axonal injury. The advent of highly sensitive analytical platforms that enable reliable quantification of neurofilaments in blood samples and simplify longitudinal follow-up has paved the way for the development of neurofilaments as a biomarker in clinical practice. Potential applications include assessment of disease activity, monitoring of treatment responses, and determining prognosis in many acute and chronic neurological disorders as well as their use as an outcome measure in trials of novel therapies. Progress has now moved the measurement of neurofilaments to the doorstep of routine clinical practice for the evaluation of individuals. In this Review, we first outline current knowledge on the structure and function of neurofilaments. We then discuss analytical and statistical approaches and challenges in determining neurofilament levels in different clinical contexts and assess the implications of neurofilament light chain (NfL) levels in normal ageing and the confounding factors that need to be considered when interpreting NfL measures. In addition, we summarize the current value and potential clinical applications of neurofilaments as a biomarker of neuro-axonal damage in a range of neurological disorders, including multiple sclerosis, Alzheimer disease, frontotemporal dementia, amyotrophic lateral sclerosis, stroke and cerebrovascular disease, traumatic brain injury, and Parkinson disease. We also consider the steps needed to complete the translation of neurofilaments from the laboratory to the management of neurological diseases in clinical practice.

Efficacy and safety results after >3.5 years of treatment with the Bruton's tyrosine kinase inhibitor evobrutinib in relapsing multiple sclerosis: Long-term follow-up of a Phase II randomised clinical trial with a cerebrospinal fluid sub-study.

BACKGROUND: Evobrutinib - an oral, central nervous system (CNS)-penetrant, and highly selective Bruton's tyrosine kinase inhibitor - has shown efficacy in a 48-week, double-blind, Phase II trial in patients with relapsing MS. OBJECTIVE: Report results of the Phase II open-label extension (OLE; up to week 192 from randomisation) and a cerebrospinal fluid (CSF) sub-study. METHODS: In the 48-week double-blind period (DBP), patients received evobrutinib 25 mg once-daily, 75 mg once-daily, 75 mg twice-daily or placebo (switched to evobrutinib 25 mg once-daily after week 24). Patients could then enter the OLE, receiving evobrutinib 75 mg once-daily (mean (± standard deviation (SD)) duration = 50.6 weeks (±6.0)) before switching to 75 mg twice-daily. RESULTS: Of 164 evobrutinib-treated patients who entered the OLE, 128 (78.0%) completed ⩾192 weeks of treatment. Patients receiving DBP evobrutinib 75 mg twice-daily: annualised relapse rate at week 48 (0.11 (95% confidence interval (CI) = 0.04-0.25)) was maintained with the OLE twice-daily dose up to week 192 (0.11 (0.05-0.22)); Expanded Disability Status Scale score remained stable; serum neurofilament light chain fell to levels like a non-MS population (Z-scores); T1 gadolinium-enhancing lesion numbers remained low. No new safety signals were identified. In the OLE, evobrutinib was detected in the CSF of all sub-study patients. CONCLUSION: Long-term evobrutinib treatment was well tolerated and associated with a sustained low level of disease activity. Evobrutinib was present in CSF at concentrations similar to plasma.

Combining randomized and non-randomized data to predict heterogeneous effects of competing treatments.

Some patients benefit from a treatment while others may do so less or do not benefit at all. We have previously developed a two-stage network meta-regression prediction model that synthesized randomized trials and evaluates how treatment effects vary across patient characteristics. In this article, we extended this model to combine different sources of types in different formats: aggregate data (AD) and individual participant data (IPD) from randomized and non-randomized evidence. In the first stage, a prognostic model is developed to predict the baseline risk of the outcome using a large cohort study. In the second stage, we recalibrated this prognostic model to improve our predictions for patients enrolled in randomized trials. In the third stage, we used the baseline risk as effect modifier in a network meta-regression model combining AD, IPD randomized clinical trial to estimate heterogeneous treatment effects. We illustrated the approach in the re-analysis of a network of studies comparing three drugs for relapsing-remitting multiple sclerosis. Several patient characteristics influence the baseline risk of relapse, which in turn modifies the effect of the drugs. The proposed model makes personalized predictions for health outcomes under several treatment options and encompasses all relevant randomized and non-randomized evidence.

Complement Activation Is Associated With Disease Severity in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Histopathologic studies have identified immunoglobulin (Ig) deposition and complement activation as contributors of CNS tissue damage in multiple sclerosis (MS). Intrathecal IgM synthesis is associated with higher MS disease activity and severity, and IgM is the strongest complement-activating immunoglobulin. In this study, we investigated whether complement components (CCs) and complement activation products (CAPs) are increased in persons with MS, especially in those with an intrathecal IgM synthesis, and whether they are associated with disease severity and progression. METHODS: CC and CAP levels were quantified in plasma and CSF of 112 patients with clinically isolated syndrome (CIS), 127 patients with MS (90 relapsing-remitting, 14 primary progressive, and 23 secondary progressive), 31 inflammatory neurologic disease, and 44 symptomatic controls from the Basel CSF databank study. Patients with CIS/MS were followed in the Swiss MS cohort study (median 6.3 years). Levels of CC/CAP between diagnosis groups were compared; in CIS/MS, associations of CC/CAP levels with intrathecal Ig synthesis, baseline Expanded Disability Status Scale (EDSS) scores, MS Severity Score (MSSS), and neurofilament light chain (NfL) levels were investigated by linear regression, adjusted for age, sex, and albumin quotient. RESULTS: CSF (but not plasma) levels of C3a, C4a, Ba, and Bb were increased in patients with CIS/MS, being most pronounced in those with an additional intrathecal IgM production. In CIS, doubling of C3a and C4a in CSF was associated with 0.31 (CI 0.06-0.56; p = 0.016) and 0.32 (0.02-0.62; p = 0.041) increased EDSS scores at lumbar puncture. Similarly, doubling of C3a and Ba in CIS/MS was associated with 0.61 (0.19-1.03; p < 0.01) and 0.74 (0.18-1.31; p = 0.016) increased future MSSS. In CIS/MS, CSF levels of C3a, C4a, Ba, and Bb were associated with increased CSF NfL levels, e.g., doubling of C3a was associated with an increase of 58% (Est. 1.58; CI 1.37-1.81; p < 0.0001). DISCUSSION: CNS-compartmentalized activation of the classical and alternative pathways of complement is increased in CIS/MS and associated with the presence of an intrathecal IgM production. Increased complement activation within the CSF correlates with EDSS, future MSSS, and NfL levels, supporting the concept that complement activation contributes to MS pathology and disease progression. Complement inhibition should be explored as therapeutic target to attenuate disease severity and progression in MS.

Effects of obstructive sleep apnea treatment on neurodegenerative biomarker neurofilament light chain and cognitive performance.

Obstructive sleep apnea is associated with cognitive impairment and increased risk for neurodegenerative diseases. Obstructive sleep apnea treatment with positive airway pressure therapy helps to improve cognitive symptoms and reduces long-term dementia risk. To test whether these treatment effects are due to a reduction in neuronal damage, we examined longitudinal changes in the neurodegenerative serum neurofilament light chain and cognitive performance of patients with obstructive sleep apnea. In this study, 17 patients with obstructive sleep apnea completed baseline and follow-up (9 month after starting PAP treatment) investigation of sleep, daytime symptoms, cognitive testing and serum neurofilament light chain measurements. Depending on treatment adherence and efficacy, participants were assigned either to the effective treatment (n = 10) or non-effective treatment group (n = 7). As results at baseline lower mean oxygen saturation during sleep was associated with higher serum neurofilament light chain. Patients in the non-effective treatment group showed a significant increase of age-adjusted percentile of serum neurofilament light chain levels at follow-up, whereas serum neurofilament light chain values remained constant in the effective treatment group. At a functional level, effective treatment leads to an improvement in processing speed, which was not the case in the non-effective treatment group. Longitudinal changes of age-adjusted serum neurofilament light chain levels were associated with changes in cognitive performance. To conclude, this longitudinal observational study showed that effective obstructive sleep apnea treatment positively affects the amount of neuronal damage as well as working memory performance. As cognitive symptoms might not only be attributed to obstructive sleep apnea-related sleep deficiency, but also neurodegeneration, our results underline the importance of treatment adherence and efficacy for the prevention of neuronal damage and cognitive consequences.

Polygenic risk for Alzheimer's disease is associated with neuroaxonal damage before onset of clinical symptoms.

INTRODUCTION: Establishing valid diagnostic strategies is a precondition for successful therapeutic intervention in Alzheimer's disease (AD). METHODS: One hundred forty-four healthy 75-year-old participants from the Vienna-Transdanube-Aging longitudinal cohort study were tested for neuroaxonal damage by single molecular array (Simoa) plasma neurofilament light chain (NfL) levels at baseline, 30, 60, and 90 months, and onset of AD dementia. Individual risk for sporadic AD was estimated by continuous shrinkage polygenic risk score (PRS-CS, genome-wide association study). RESULTS: Nineteen participants developed AD after a median of 60 months (interquartile range 30). In participants with AD, baseline NfL plasma levels correlated with PRS-CS (r = 0.75, p < 0.001; difference to controls: Fisher's r-to-z: z = 3.89, p < 0.001). PRS-CS combined with baseline plasma NfL predicted onset of AD (p < 0.01). DISCUSSION: Our data suggest that polygenic risk for AD and plasma NfL closely interact years before onset of clinical symptoms. Peripheral NfL may serve as a diagnostic measure supporting early therapeutic intervention and secondary prevention in AD.

Association of Spinal Cord Atrophy and Brain Paramagnetic Rim Lesions With Progression Independent of Relapse Activity in People With MS.

BACKGROUND AND OBJECTIVES: Progression independent of relapse activity (PIRA) is a crucial determinant of overall disability accumulation in multiple sclerosis (MS). Accelerated brain atrophy has been shown in patients experiencing PIRA. In this study, we assessed the relation between PIRA and neurodegenerative processes reflected by (1) longitudinal spinal cord atrophy and (2) brain paramagnetic rim lesions (PRLs). Besides, the same relationship was investigated in progressive MS (PMS). Last, we explored the value of cross-sectional brain and spinal cord volumetric measurements in predicting PIRA. METHODS: From an ongoing multicentric cohort study, we selected patients with MS with (1) availability of a susceptibility-based MRI scan and (2) regular clinical and conventional MRI follow-up in the 4 years before the susceptibility-based MRI. Comparisons in spinal cord atrophy rates (explored with linear mixed-effect models) and PRL count (explored with negative binomial regression models) were performed between: (1) relapsing-remitting (RRMS) and PMS phenotypes and (2) patients experiencing PIRA and patients without confirmed disability accumulation (CDA) during follow-up (both considering the entire cohort and the subgroup of patients with RRMS). Associations between baseline MRI volumetric measurements and time to PIRA were explored with multivariable Cox regression analyses. RESULTS: In total, 445 patients with MS (64.9% female; mean [SD] age at baseline 45.0 [11.4] years; 11.2% with PMS) were enrolled. Compared with patients with RRMS, those with PMS had accelerated cervical cord atrophy (mean difference in annual percentage volume change [MD-APC] -1.41; p = 0.004) and higher PRL load (incidence rate ratio [IRR] 1.93; p = 0.005). Increased spinal cord atrophy (MD-APC -1.39; p = 0.0008) and PRL burden (IRR 1.95; p = 0.0008) were measured in patients with PIRA compared with patients without CDA; such differences were also confirmed when restricting the analysis to patients with RRMS. Baseline volumetric measurements of the cervical cord, whole brain, and cerebral cortex significantly predicted time to PIRA (all p ≤ 0.002). DISCUSSION: Our results show that PIRA is associated with both increased spinal cord atrophy and PRL burden, and this association is evident also in patients with RRMS. These findings further point to the need to develop targeted treatment strategies for PIRA to prevent irreversible neuroaxonal loss and optimize long-term outcomes of patients with MS.

Serum biomarker levels predict disability progression in patients with primary progressive multiple sclerosis.

BACKGROUND: We aimed to investigate the potential of serum biomarker levels to predict disability progression in a multicentric real-world cohort of patients with primary progressive multiple sclerosis (PPMS). METHODS: A total of 141 patients with PPMS from 18 European MS centres were included. Disability progression was investigated using change in Expanded Disability Status Scale (EDSS) score over three time intervals: baseline to 2 years, 6 years and to the last follow-up. Serum levels of neurofilament light chain (sNfL), glial fibrillar acidic protein (sGFAP) and chitinase 3-like 1 (sCHI3L1) were measured using single-molecule array assays at baseline. Correlations between biomarker levels, and between biomarkers and age were quantified using Spearman's r. Univariable and multivariable linear models were performed to assess associations between biomarker levels and EDSS change over the different time periods. RESULTS: Median (IQR) age of patients was 52.9 (46.4-58.5) years, and 58 (41.1%) were men. Median follow-up time was 9.1 (7.0-12.6) years. Only 8 (5.7%) patients received treatment during follow-up. sNfL and sGFAP levels were moderately correlated (r=0.43) and both weakly correlated with sCHI3L1 levels (r=0.19 and r=0.17, respectively). In multivariable analyses, levels of the three biomarkers were associated with EDSS changes across all time periods. However, when analysis was restricted to non-inflammatory patients according to clinical and radiological parameters (n=64), only sCHI3L1 levels remained associated with future EDSS change. CONCLUSIONS: Levels of sNfL, sGFAP and sCHI3L1 are prognostic biomarkers associated with disability progression in patients with PPMS, being CHI3L1 findings less dependent on the inflammatory component associated with disease progression.

Serum neurofilament light and white matter characteristics in the general population: a longitudinal analysis.

Neurofilament light polypeptide (NfL) is a component of the neuronal cytoskeleton and particularly abundant in large-caliber axons. When axonal injury occurs, NfL is released and reaches the cerebrospinal fluid and the blood. Associations between NfL and white matter alterations have previously been observed in studies based on patients with neurological diseases. The current study aimed to explore the relationship between serum NfL (sNfL) and white matter characteristics in a population-based sample. The cross-sectional associations between sNfL as dependent variable, fractional anisotropy (FA), and white matter lesion (WML) volume were analyzed with linear regression models in 307 community-dwelling adults aged between 35 and 65 years. These analyses were repeated with additional adjustment for the potential confounders age, sex, and body mass index (BMI). Longitudinal associations over a mean follow-up of 5.39 years were analyzed with linear mixed models. The unadjusted cross-sectional models yielded significant associations between sNfL, WML volume, and FA, respectively. However, after the adjustment for confounders, these associations did not reach significance. In the longitudinal analyses, the findings corroborated the baseline findings showing no significant associations between sNfL and white matter macrostructure and microstructure beyond the effects of age. In synopsis with previous studies in patients with acute neurological diseases showing a significant association of sNfL with white matter changes beyond the effects of age, the present results based on a sample from the general population suggest the perspective that changes in sNfL reflect age-related effects that also manifest in altered white matter macrostructure and microstructure.

Serum glial fibrillary acidic protein and disability progression in progressive multiple sclerosis.

OBJECTIVE: Progression prediction is a significant unmet need in people with progressive multiple sclerosis (pwPMS). Studies on glial fibrillary acidic protein (GFAP) have either been limited to single center with relapsing MS or were based solely on Expanded Disability Status Scale (EDSS), which limits its generalizability to state-of-the-art clinical settings and trials applying combined outcome parameters. METHODS: Serum GFAP and NfL (neurofilament light chain) were investigated in EmBioProMS participants with primary (PP) or secondary progressive MS. Six months confirmed disability progression (CDP) was defined using combined outcome parameters (EDSS, timed-25-foot walk test (T25FW), and nine-hole-peg-test (9HPT)). RESULTS: 243 subjects (135 PPMS, 108 SPMS, age 55.5, IQR [49.7-61.2], 135 female, median follow-up: 29.3 months [17.9-40.9]) were included. NfL (age-) and GFAP (age- and sex-) adjusted Z scores were higher in pwPMS compared to HC (p < 0.001 for both). 111 (32.8%) CDP events were diagnosed in participants with ≥3 visits (n = 169). GFAP Z score >3 was associated with higher risk for CDP in participants with low NfL Z score (i.e., ≤1.0) (HR: 2.38 [1.12-5.08], p = 0.025). In PPMS, GFAP Z score >3 was associated with higher risk for CDP (HR: 2.88 [1.21-6.84], p = 0.016). Risk was further increased in PPMS subjects with high GFAP when NfL is low (HR: 4.31 [1.53-12.13], p = 0.006). INTERPRETATION: Blood GFAP may help identify pwPPMS at risk of progression. Combination of high GFAP and low NfL levels could distinguish non-active pwPMS with particularly high progression risk.

Neurofilament Light Chain Elevation and Disability Progression in Multiple Sclerosis.

Importance: Mechanisms contributing to disability accumulation in multiple sclerosis (MS) are poorly understood. Blood neurofilament light chain (NfL) level, a marker of neuroaxonal injury, correlates robustly with disease activity in people with MS (MS); however, data on the association between NfL level and disability accumulation have been conflicting. Objective: To determine whether and when NfL levels are elevated in the context of confirmed disability worsening (CDW). Design, Setting, and Participants: This study included 2 observational cohorts: results from the Expression, Proteomics, Imaging, Clinical (EPIC) study at the University of California San Francisco (since 2004) were confirmed in the Swiss Multiple Sclerosis Cohort (SMSC), a multicenter study in 8 centers since 2012. Data were extracted from EPIC in April 2022 (sampling July 1, 2004, to December 20, 2016) and SMSC in December 2022 (sampling June 6, 2012, to September 2, 2021). The study included 2 observational cohorts in tertiary MS centers. All participants of both cohorts with available NfL results were included in the study, and no eligible participants were excluded or declined to participate. Exposure: Association between NfL z scores and CDW. Main Outcome Measures: CDW was defined as Expanded Disability Status Scale (EDSS) worsening that was confirmed after 6 or more months and classified into CDW associated with clinical relapses (CDW-R) or independent of clinical relapses (CDW-NR). Visits were classified in relation to the disability worsening events into CDW(-2) for 2 visits preceding event, CDW(-1) for directly preceding event, CDW(event) for first diagnosis of EDSS increase, and the confirmation visit. Mixed linear and Cox regression models were used to evaluate NfL dynamics and to assess the association of NfL with future CDW, respectively. Results: A total of 3906 EPIC visits (609 participants; median [IQR] age, 42.0 [35.0-50.0] years; 424 female [69.6%]) and 8901 SMSC visits (1290 participants; median [IQR] age, 41.2 [32.5-49.9] years; 850 female [65.9%]) were included. In CDW-R (EPIC, 36 events; SMSC, 93 events), NfL z scores were 0.71 (95% CI, 0.35-1.07; P < .001) units higher at CDW-R(-1) in EPIC and 0.32 (95% CI, 0.14-0.49; P < .001) in SMSC compared with stable MS samples. NfL elevation could be detected preceding CDW-NR (EPIC, 191 events; SMSC, 342 events) at CDW-NR(-2) (EPIC: 0.23; 95% CI, 0.01-0.45; P = .04; SMSC: 0.28; 95% CI, 0.18-0.37; P < .001) and at CDW-NR(-1) (EPIC: 0.27; 95% CI, 0.11-0.44; P < .001; SMSC: 0.09; 95% CI, 0-0.18; P = .06). Those findings were replicated in the subgroup with relapsing-remitting MS. Time-to-event analysis confirmed the association between NfL levels and future CDW-R within approximately 1 year and CDW-NR (in approximately 1-2 years). Conclusions and Relevance: This cohort study documents the occurrence of NfL elevation in advance of clinical worsening and may hint to a potential window of ongoing dynamic central nervous system pathology that precedes the diagnosis of CDW.

Harmonizing Definitions for Progression Independent of Relapse Activity in Multiple Sclerosis: A Systematic Review.

Importance: Emerging evidence suggests that progression independent of relapse activity (PIRA) is a substantial contributor to long-term disability accumulation in relapsing-remitting multiple sclerosis (RRMS). To date, there is no uniform agreed-upon definition of PIRA, limiting the comparability of published studies. Objective: To summarize the current evidence about PIRA based on a systematic review, to discuss the various terminologies used in the context of PIRA, and to propose a harmonized definition for PIRA for use in clinical practice and future trials. Evidence Review: A literature search was conducted using the search terms multiple sclerosis, PIRA, progression independent of relapse activity, silent progression, and progression unrelated to relapses in PubMed, Embase, Cochrane, and Web of Science, published between January 1990 and December 2022. Findings: Of 119 identified single records, 48 eligible studies were analyzed. PIRA was reported to occur in roughly 5% of all patients with RRMS per annum, causing at least 50% of all disability accrual events in typical RRMS. The proportion of PIRA vs relapse-associated worsening increased with age, longer disease duration, and, despite lower absolute event numbers, potent suppression of relapses by highly effective disease-modifying therapy. However, different studies used various definitions of PIRA, rendering the comparability of studies difficult. Conclusion and Relevance: PIRA is the most frequent manifestation of disability accumulation across the full spectrum of traditional MS phenotypes, including clinically isolated syndrome and early RRMS. The harmonized definition suggested here may improve the comparability of results in current and future cohorts and data sets.

Optical coherence tomography versus other biomarkers: Associations with physical and cognitive disability in multiple sclerosis.

BACKGROUND: Optical coherence tomography (OCT) is a biomarker of neuroaxonal loss in multiple sclerosis (MS). OBJECTIVE: The objective was to assess the relative role of OCT, next to magnetic resonance imaging (MRI) and serum markers of disability in MS. METHODS: A total of 100 patients and 52 controls underwent OCT to determine peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell-inner plexiform layers (GCIPL). Serum neurofilament light chain (sNfL), total lesion volume (TLV), and brain parenchymal fraction (BPF) were also assessed. The associations of OCT with disability were examined in linear regression models with correction for age, vision, and education. RESULTS: In patients, pRNFL was associated with the Symbol Digit Modalities Test (SDMT; p = 0.030). In the multivariate analysis including sNfL and MRI measures, pRNFL (ß = 0.19, p = 0.044) and TLV (ß = -0.24, p = 0.023) were the only markers associated with the SDMT. pRNFL (p < 0.001) and GCIPL (p < 0.001) showed associations with the Expanded Disability Status Scale (EDSS). In the multivariate analysis, GCIPL showed the strongest association with the EDSS (ß = -0.32, p < 0.001) followed by sNfL (ß = 0.18, p = 0.024). CONCLUSION: The associations of OCT measures with cognitive and physical disability were independent of serum and brain MRI markers of neuroaxonal loss. OCT can be an important tool for stratification in MS, while longitudinal studies using combinations of biomarkers are warranted.

Comparative analysis of dimethyl fumarate and teriflunomide in relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: In relapsing-remitting multiple sclerosis (RRMS), analyses from observational studies comparing dimethyl fumarate (DMF) and teriflunomide showed conflicting results. We aimed to compare the effectiveness of DMF and teriflunomide in a real-world setting, where both drugs are licensed as first-line therapies for RRMS. METHODS: We included all patients who initiated DMF or teriflunomide between 2013 and 2022, listed in the Swiss National Treatment Registry. Coarsened exact matching was applied using age, gender, disease duration, baseline Expanded Disability Status Scale (EDSS) score, time since last relapse, and relapse rate in the previous year as matching variables. Time to relapse and time to 12-month confirmed EDSS worsening were compared using Cox proportional hazard models. RESULTS: In total, 2028 patients were included in this study, of whom 1498 were matched (DMF: n = 1090, 69.6% female, mean age 45.1 years, median EDSS score 2.0; teriflunomide: n = 408, 68.9% female, mean age 45.1 years, median EDSS score 2.0). Time to relapse and time to EDSS worsening was longer in the DMF than the teriflunomide group (hazard ratio 0.734, p = 0.026 and hazard ratio 0.576, p = 0.003, respectively). CONCLUSION: Analysis of real-world data showed that DMF treatment was associated with more favorable outcomes than teriflunomide treatment.

Serum neurofilament light chain reference database for individual application in paediatric care: a retrospective modelling and validation study.

BACKGROUND: Neurological conditions represent an important driver of paediatric disability burden worldwide. Measurement of serum neurofilament light chain (sNfL) concentrations, a specific marker of neuroaxonal injury, has the potential to contribute to the management of children with such conditions. In this context, the European Medicines Agency recently declared age-adjusted reference values for sNfL a top research priority. We aimed to establish an age-adjusted sNfL reference range database in a population of healthy children and adolescents, and to validate this database in paediatric patients with neurological conditions to affirm its clinical applicability. METHODS: To generate a paediatric sNfL reference dataset, sNfL values were measured in a population of healthy children and adolescents (aged 0-22 years) from two large cohorts in Europe (the Coronavirus Antibodies in Kids from Bavaria study, Germany) and North America (a US Network of Paediatric Multiple Sclerosis Centers paediatric case-control cohort). Children with active or previous COVID-19 infection or SARS-CoV-2 antibody positivity at the time of sampling, or a history of primary systemic or neurological conditions were excluded. Linear models were used to restrospectively study the effect of age and weight on sNfL concentrations. We modelled the distribution of sNfL concentrations as a function of age-related physiological changes to derive reference percentile and Z score values via a generalised additive model for location, scale, and shape. The clinical utility of the new reference dataset was assessed in children and adolescents (aged 1-19 years) with neurological diseases (epilepsy, traumatic brain injury, bacterial CNS infections, paediatric-onset multiple sclerosis, and myelin oligodendrocyte glycoprotein antibody-associated disease) from the paediatric neuroimmunology clinic at the University of California San Francisco (San Francisco, CA, USA) and the Children's Hospital of the University of Regensburg (Regensburg, Germany). FINDINGS: Samples from 2667 healthy children and adolescents (1336 [50·1%] girls and 1331 [49·9%] boys; median age 8·0 years [IQR 4·0-12·0]) were used to generate the reference database covering neonatal age to adolescence (target age range 0-20 years). In the healthy population, sNfL concentrations decreased with age by an estimated 6·8% per year until age 10·3 years (estimated multiplicative effect per 1 year increase 0·93 [95% CI 0·93-0·94], p<0·0001) and was mostly stable thereafter up to age 22 years (1·00 [0·52-1·94], p>0·99). Independent of age, the magnitude of the effect of weight on sNfL concentrations was marginal. Samples from 220 children with neurological conditions (134 [60·9%] girls and 86 [39·1%] boys; median age 14·7 years [IQR 10·8-16·5]) were used to validate the clinical utility of the reference Z scores. In this population, age-adjusted sNfL Z scores were higher than in the reference population of healthy children and adolescents (p<0·0001) with higher effect size metrics (Cohen's d=1·56) compared with the application of raw sNfL concentrations (d=1·28). INTERPRETATION: The established normative sNfL values in children and adolescents provide a foundation for the clinical application of sNfL in the paediatric population. Compared with absolute sNfL values, the use of sNfL Z score was associated with higher effect size metrics and allowed for more accurate estimation of the extent of ongoing neuroaxonal damage in individual patients. FUNDING: Swiss National Science Foundation, US National Institutes of Health, and the National Multiple Sclerosis Society.

Concentrations of Serum Brain Injury Biomarkers Following SARS-CoV-2 Infection in Individuals with and without Long-COVID-Results from the Prospective Population-Based COVI-GAPP Study.

It is unknown whether neurological symptoms are associated with brain injury after SARS-CoV-2 infections and whether brain injury and related symptoms also emerge in Long-COVID patients. Biomarkers such as serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) can be used to elucidate neuro-axonal and astroglial injuries. We investigated whether these biomarkers are associated with COVID-19 infection status, associated symptoms and Long-COVID. From 146 individuals of the general population with a post-acute, mild-to-moderate SARS-CoV-2 infection, sNfL and sGFAP were measured before, during and after (five and ten months) the infection. Individual symptoms and Long-COVID status were assessed using questionnaires. Neurological associated symptoms were described for individuals after a mild and moderate COVID-19 infection; however, sNfL (p = 0.74) and sGFAP (p = 0.24) did not change and were not associated with headache (p = 0.51), fatigue (p = 0.93), anosmia (p = 0.77) or ageusia (p = 0.47). In Long-COVID patients, sGFAP (p = 0.038), but not sNfL (p = 0.58), significantly increased but was not associated with neurological associated symptoms. Long-COVID status, but not post-acute SARS-CoV-2 infections, may be associated with astroglial injury/activation, even if neurological associated symptoms were not correlated.

Serum Neurofilament light chain (NfL) levels in children with and without neurologic diseases.

BACKGROUND/OBJECTIVE: Serum neurofilament light chain (sNfL) is a specific biomarker of neuronal damage. Elevated sNfL levels have been reported in numerous neurologic diseases in adults, whereas data on sNfL in the pediatric population are incomplete. The aim of this study was to investigate sNfL levels in children with various acute and chronic neurologic disorders and describe the age dependence of sNfL from infancy to adolescence. METHODS: The total study cohort of this prospective cross-sectional study consisted of 222 children aged from 0 to 17 years. Patients' clinical data were reviewed and patients were assigned to the following groups: 101 (45.5%) controls, 34 (15.3%) febrile controls, 23 (10.4%) acute neurologic conditions (meningitis, facial nerve palsy, traumatic brain injury, or shunt dysfunction in hydrocephalus), 37 (16.7%) febrile seizures, 6 (2.7%) epileptic seizures, 18 (8.1%) chronic neurologic conditions (autism, cerebral palsy, inborn mitochondrial disorder, intracranial hypertension, spina bifida, or chromosomal abnormalities), and 3 (1.4%) severe systemic disease. sNfL levels were measured using a sensitive single-molecule array assay. RESULTS: There were no significant differences in sNfL levels between controls, febrile controls, febrile seizures, epileptic seizures, acute neurologic conditions, and chronic neurologic conditions. In children with severe systemic disorders, by far the highest NfL levels were found with an sNfL of 429 pg/ml in a patient with neuroblastoma, 126 pg/ml in a patient with cranial nerve palsy and pharyngeal Burkitt's lymphoma, and 42 pg/ml in a child with renal transplant rejection. The relationship between sNfL and age could be described by a second order polynomial with an R2 of 0.153 with a decrease of sNfL by 3.2% per year from birth to age 12 years and thereafter an increase by 2.7% per year until age 18 years. CONCLUSIONS: In this study cohort, sNfL levels were not elevated in children with febrile or epileptic seizures, or various other neurologic diseases. Strikingly high sNfL levels were detected in children with oncologic disease or transplant rejection. A biphasic sNfL age-dependency was documented, with highest levels in infancy and late adolescence and the lowest levels in middle school age.

Prognostic performance of blood neurofilament light chain protein in hospitalized COVID-19 patients without major central nervous system manifestations: an individual participant data meta-analysis.

BACKGROUND AND AIMS: To investigate the prognostic value of blood neurofilament light chain protein (NfL) levels in the acute phase of coronavirus disease 2019 (COVID-19). METHODS: We conducted an individual participant data (IPD) meta-analysis after screening on MEDLINE and Scopus to May 23rd 2022. We included studies with hospitalized adult COVID-19 patients without major COVID-19-associated central nervous system (CNS) manifestations and with a measurement of blood NfL in the acute phase as well as data regarding at least one clinical outcome including intensive care unit (ICU) admission, need of mechanical ventilation (MV) and death. We derived the age-adjusted measures NfL Z scores and conducted mixed-effects modelling to test associations between NfL Z scores and other variables, encompassing clinical outcomes. Summary receiver operating characteristic curves (SROCs) were used to calculate the area under the curve (AUC) for blood NfL. RESULTS: We identified 382 records, of which 7 studies were included with a total of 669 hospitalized COVID-19 cases (mean age 66.2 ± 15.0 years, 68.1% males). Median NfL Z score at admission was elevated compared to the age-corrected reference population (2.37, IQR: 1.13-3.06, referring to 99th percentile in healthy controls). NfL Z scores were significantly associated with disease duration and severity. Higher NfL Z scores were associated with a higher likelihood of ICU admission, need of MV, and death. SROCs revealed AUCs of 0.74, 0.80 and 0.71 for mortality, need of MV and ICU admission, respectively. CONCLUSIONS: Blood NfL levels were elevated in the acute phase of COVID-19 patients without major CNS manifestations and associated with clinical severity and poor outcome. The marker might ameliorate the performance of prognostic multivariable algorithms in COVID-19.