No increase of serum neurofilament light in relapsing-remitting multiple sclerosis patients switching from standard to extended-interval dosing of natalizumab

Serum neurofilament light for detecting disease activity in individual patients in multiple sclerosis: A 48-week prospective single-center study

BACKGROUND

Serum neurofilament light (sNfL) reflects neuroaxonal damage and is now used as an outcome in treatment trials of relapsing-remitting multiple sclerosis (RRMS). However, the diagnostic properties of sNfL for monitoring disease activity in individual patients warrant further investigations.

METHOD

Patients with suspected relapse and/or contrast-enhancing lesions (CELs) were consecutively included and performed magnetic resonance imaging (MRI) of the brain at baseline and weeks 28 and 48. Serum was obtained at baseline and 2, 4, 8, 16, 24, and 48 weeks. Neurofilament light concentration was measured using Single molecule array technology.

RESULTS

We included 44 patients, 40 with RRMS and 4 with clinically isolated syndrome. The median sNfL level peaked at 2 weeks post-baseline (14.6 ng/L, interquartile range (IQR); 9.3-31.6) and reached nadir at 48 weeks (9.1 ng/L, IQR; 5.5-15.0), equivalent to the median sNfL of controls (9.1 ng/L, IQR; 7.4-12). A baseline Z-score of more than 1.1 (area under the curve; 0.78, p < 0.0001) had a sensitivity of 81% and specificity of 70% to detect disease activity.

CONCLUSION

One out of five patients with relapse and/or CELs did not change significantly in post-baseline sNfL levels. The utility of repeated sNfL measurements to monitor disease activity is complementary rather than a substitute for clinical and MRI measures.

Prospective trial of natalizumab personalised extended interval dosing by therapeutic drug monitoring in relapsing-remitting multiple sclerosis (NEXT-MS)

BACKGROUND

Extended interval dosing (EID) of natalizumab is a promising strategy to optimise treatment in multiple sclerosis (MS). Personalised EID by therapeutic drug monitoring can enable further extension of treatment intervals.

METHODS

The NEXT-MS trial is an investigator-initiated prospective phase IV non-randomised study. Adults with a diagnosis of relapsing-remitting MS who received ≥6 natalizumab infusions were included in three groups: personalised EID with a target drug trough concentration of 10 µg/mL (EID10), an exploratory group of personalised EID with a target of 5 µg/mL (EID5) and standard interval dosing (SID) of 4 weeks. The primary outcome is radiological disease activity (new/newly enlarged T2 lesions) comparing the EID10 group to a historical cohort of SID (HSID).

RESULTS

Results of the first phase of the NEXT-MS trial are reported here (n=376) as the study will continue with an amended protocol. In the EID10 group (n=251), incidence rate of radiological activity was 10.0 per 1000 person-years, which was non-inferior to the HSID cohort (24.7 per 1000 person-years (n=87), incidence rate difference 14.7, 90% CI -4.5 to 34.0). Incidence rate of radiological activity was 10.0 per 1000 person-years in the EID5 group (n=65), and 47.0 per 1000 person-years in the SID group (n=60). Serum neurofilament light levels did not increase over time within the EID groups. There were no cases of progressive multifocal leukoencephalopathy.

CONCLUSIONS

MS disease activity is adequately controlled with personalised natalizumab EID. Interval extension to a drug trough concentration of 5 µg/mL is likely a safe target to extend natalizumab treatment intervals >6 weeks.

TRIAL REGISTRATION NUMBER

NCT04225312.

Safety and efficacy of extended versus standard interval dosing of natalizumab in multiple sclerosis patients: a systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory, immune-mediated disease affecting the central nervous system. Natalizumab, an FDA-approved monoclonal antibody for MS, has been explored for its off-label extended interval dosing (EID), suggesting a potential reduction in the risk of progressive multifocal leukoencephalopathy (PML) compared to standard interval dosing (SID). Our objective was to assess the efficacy and safety of EID in comparison to SID for natalizumab treatment in patients with MS.

METHODS

We searched PubMed, Embase, WOS, Scopus, Ovid, Science Direct, Clinical trials.gov, and Cochrane Library. Our assessed outcomes were clinical relapses, MRI activity, change in expanded disability status scale [EDSS], and the risk of PML. The EID group was defined as 5 to 8 weeks [EID (Q5-8W)]. The analysis was conducted using RevMan ver. 5.4. The effect estimates were presented as a risk ratio [RR] or mean difference with 95% confidence intervals [CI] using SID group as the reference for comparisons.

RESULTS

Fourteen studies met our inclusion criteria: 2 RCTs, 1 switched single-arm trial, and 12 observational studies. No significant differences were found in all efficacy outcomes of interest. Risk of clinical relapses [RR = 0.90, (95%CI 0.80, 1.02)], risk of new or newly enlarging T2 hyperintense MRI lesions [RR = 0.78, (95%CI 0.59, 1.04)], risk gadolinium enhancing lesions [RR = 1.30, (95%CI 0.98, 1.72)], change in EDSS [MD = 0.09 (95%CI - 0.57, 0.76)], risk of PML [RR = 1.09, 95%CI (0.24, 4.94)].

CONCLUSION

In summary, our meta-analysis indicates that natalizumab maintains its effectiveness under extended interval dosing [up to 8 weeks], presenting comparable risks for clinical relapses, MRI lesions, EDSS, and PML. Caution is advised given study limitations and heterogeneity. Robust conclusions necessitate well-designed high-quality prospective studies.

Neurofilament Light Chain in Adult and Pediatric Multiple Sclerosis: A Promising Biomarker to Better Characterize Disease Activity and Personalize MS Treatment

Many biological markers have been explored in multiple sclerosis (MS) to better quantify disease burden and better evaluate response to treatments, beyond clinical and MRI data. Among these, neurofilament light chain (Nf-L), although non-specific for this disease and found to be increased in other neurological conditions, has been shown to be the most promising biomarker for assessing axonal damage in MS, with a definite role in predicting the development of MS in patients at the first neurological episode suggestive of MS, and also in a preclinical phase. There is strong evidence that Nf-L levels are increased more in relapsing versus stable MS patients, and that they predict future disease evolution (relapses, progression, MRI measures of activity/progression) in MS patients, providing information on response to therapy, helping to anticipate clinical decisions in patients with an apparently stable evolution, and identifying patient non-responders to disease-modifying treatments. Moreover, Nf-L can contribute to the better understanding of the mechanisms of demyelination and axonal damage in adult and pediatric MS. A fundamental requirement for its clinical use is the accurate standardization of normal values, corrected for confounding factors, in particular age, sex, body mass index, and presence of comorbidities. In this review, a guide is provided to update clinicians on the use of Nf-L in clinical activity.

CYBA allelic variants are associated with severity and recovery in Guillain-Barré syndrome

BACKGROUND AND AIMS

Guillain-Barré syndrome (GBS) is a rare, acute neuropathy characterized by ascending muscle weakness. Age, axonal GBS variants, and antecedent Campylobacter jejuni infection are associated with severe GBS, but the detailed mechanisms of nerve damage are only partly explored. Pro-inflammatory myeloid cells express NADPH oxidases (NOX) that generate tissue-toxic reactive oxygen species (ROS) that are implicated in neurodegenerative diseases. This study analyzed the impact of variants of the gene encoding the functional NOX subunit CYBA (p22phox ) on acute severity, axonal damage, and recovery in adult GBS patients.

METHODS

Extracted DNA from 121 patients was genotyped for allelic variation at rs1049254 and rs4673 within CYBA using real-time quantitative polymerase chain reaction. Serum neurofilament light chain was quantified by single molecule array. Patients were followed for severity and motor function recovery for up to 13 years.

RESULTS

CYBA genotypes linked to reduced formation of ROS, i.e. rs1049254/G and rs4673/A, were significantly associated with unassisted ventilation, shorter time to normalization of serum neurofilament light chain and shorter time to regained motor function. Residual disability at follow-up was confined to patients carrying CYBA alleles associated with high formation of ROS.

INTERPRETATION

These findings implicate NOX-derived ROS in GBS pathophysiology and CYBA alleles as biomarkers of severity.

Serum Neurofilaments are a reliable biomarker to early detect PML in Multiple Sclerosis patients

BACKGROUND

The earliest detection of progressive multifocal leukoencephalopathy (PML) is crucial in Natalizumab (NTZ)-treated Multiple Sclerosis (MS) patients. This study aims to assess serum Neurofilaments (sNFL) ability to early detect PML in longitudinal patients' follow-up.

METHODS

NFL were retrospectively measured in four PML cases occurred at the Regional Referring Center for MS (CRESM, Italy), in samples collected since one year before PML diagnosis, at PML diagnosis, during PML and in post-PML follow-up. sNFL levels were interpreted according to previously defined reference values. Clinical examination and EDSS were performed at each NTZ infusion. Routinary MRI was undertaken every six months; after PML diagnosis, MRI was performed according to clinical evaluation. sNFL were also measured in 45 NTZ-treated patients experiencing NEDA-3 status for at least 12 months.

RESULTS

Patients showed different PML onsets and manifestations: in 3 patients routinary brain MRI revealed radiological signs of PML preceding different clinical manifestations, while in one patient brain MRI was performed after the clinical onset. PML diagnosis was defined at the time of the first detection of JCV DNA in cerebrospinal fluid. The following different PML phases were considered: 1. Basal (up to 4 months before PML diagnosis): sNFL values were in the normal range in all patients' samples, except for one (median 9.1 pg/ml, range 6.2-15.1 pg/ml) 2. Pre-PML (within 3 months before PML diagnosis): sNFL were elevated in all available samples (median 19.50 pg/ml, range 15.50-33.80 pg/ml). 3. PML diagnosis: sNFL were elevated in all patients (median 59.20 pg/ml, range 11.1-101.50 pg/ml). 4. PML/IRIS: during this phase, sNFL levels reached their peak (median 96.35 pg/ml, range 20.5-272.9) in all patients. 5. Post-PML (recovery phase, starting from the first MRI without enhancement, up to the end of follow-up): sNFL levels showed a decrease (median 12.80 pg/ml, range 9.30-30.60); however, based on reference values, sNFL were still elevated in 2 out of 4 patients at the end of their follow-up (622 and 887 days after PML diagnosis). sNFL were always elevated when MRI scan suggested a suspicious of PML. In NEDA-3 patients, sNFL levels were in the normal range in all patients' samples (median 4.7 pg/ml, range 1.4-8.6 pg/ml).

CONCLUSION

Elevated sNFL were observed not only at PML diagnosis, but also in pre-PML phase. At PML recovery, sNFL weren't normalized in all patients' samples, suggesting ongoing neuronal degeneration. sNFL represent a reliable biomarker and should be introduced in clinical practice as an additional/alternative parameter to MRI to early detect and monitor PML.

Serum neurofilament light levels in natalizumab-treated patients with multiple sclerosis who switch to extended interval dosing from every-4-week dosing in real-world clinical practice

BACKGROUND

Serum levels of neurofilament light chain (sNfL) are a potentially useful biomarker for assessing the efficacy of multiple sclerosis (MS) treatments.

OBJECTIVE

To compare levels of sNfL in patients with MS who switched from natalizumab every 4 weeks (Q4W) to extended interval dosing (EID) and patients who remained on Q4W dosing in real-world clinical practice.

METHODS

This was a retrospective analysis of samples from patients treated with natalizumab from 2010 to 2015 at a single center in the United States. Levels of sNfL were compared in patients who stayed on Q4W dosing or who switched to EID (parallel-arm analyses) and during Q4W and EID periods in patients who switched to EID (pre- and post-switch analyses).

RESULTS

The analysis included 139 patients (Q4W: n = 79; EID: n = 60). After adjustment, levels of sNfL did not significantly differ between patients who remained on Q4W dosing and those who switched to EID in parallel-arm analyses (adjusted Q4W-EID difference = 0.51 pg/mL; p = 0.60) or pre- and post-switch analyses (adjusted difference = 0.96 pg/mL; p = 0.10).

CONCLUSION

These sNfL biomarker results suggest that the effectiveness of natalizumab is maintained in patients who switch from Q4W dosing to EID.

Teriflunomide Concentrations in Cerebrospinal Fluid and Plasma in Patients with Multiple Sclerosis: A Pharmacokinetic Study

BACKGROUND

Teriflunomide is a disease modifying treatment (DMT) approved for relapsing-remitting multiple sclerosis (RRMS) in adults and children. It reduces lymphocyte proliferation by inhibiting the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH) and thereby the pyrimidine synthesis. Although most DMTs in multiple sclerosis (MS) modulate or inhibit the immune system in the periphery, the efficacy may improve if the agent also targets immune activity within the central nervous system (CNS), acts as a neuro-protective and enhances neuro-regeneration. The objective of this study was to determine the passage of teriflunomide over the blood-cerebrospinal fluid barrier (BCSFB).

METHODS

Plasma and cerebrospinal fluid (CSF) teriflunomide concentrations were determined at steady state in 12 patients with RRMS, treated with oral teriflunomide 14 mg once daily. Included patients were all clinically stable without relapse or disability worsening within 6 months prior from baseline and were on no other immune modulating or immunosuppressive drugs.

RESULTS

The mean teriflunomide concentrations in plasma and CSF were 38775 (SEM ± 7256) ng/mL and 68 (SEM ± 15) ng/mL, respectively. The passage over the BCSFB was 0.17 % (SEM ± 0.01). While no correlation was found between the function of the BCSFB assessed with the albumin ratio and the CSF teriflunomide concentration, the CSF and plasma teriflunomide concentrations were highly correlated (r_s = 0.90, < 0.0001).

CONCLUSIONS

Further studies are warranted to determine if the obtained CSF teriflunomide concentration reflects that in the CNS and is able to influence inflammatory and degenerative processes within the CNS.

sNFL applicability as additional monitoring tool in natalizumab extended interval dosing regimen for RRMS patients

INTRODUCTION

Extended interval dosing (EID) of Natalizumab (NAT) has been proposed to reduce progressive multifocal leukoencephalopathy (PML) risk associated with standard interval dosing (SID) in people with multiple sclerosis (MS). Previous studies have suggested that NAT effectiveness is maintained in the great majority of patients who switch from SID to EID; monitoring of disease activity is currently based exclusively on clinical and MRI parameters. Frequent MRI are expensive and not always applicable, underlining the need for biological markers able to detect central nervous system lesions. Serum Neurofilament-light chain (sNFL) currently represents the most promising biomarker of disease activity, prognosis and treatment response in MS, and their clinical suitability is increasingly evident. The objective of the present study is to assess the applicability of sNFL as additional/alternative measure of treatment efficacy during EID regimen.

METHODS

We measured sNFL by Simoa technology in longitudinal samples from 63 Relapsing Remitting (RR) MS patients switched from SID to EID.

INCLUSION CRITERIA

diagnosis of RRMS, age 18-60 years; NAT SID for at least 12 months; NEDA-3 (no evidence of disease activity) for at least 12 months; availability of at least 2 serum samples collected 6 months apart. Patients' follow-up time during EID was at least 12 months and 2 blood samples were collected after at least 6 and 12 months. Clinical examination was performed before each infusion, while MRI 6 and 12 months after NAT initiation and according to PML risk during the whole study.

RESULTS

No patients showed clinical or MRI activity during the whole follow-up. sNFL levels measured during SID and EID were comparable, without significant difference between groups. The effect of EID on NFL levels did not show significant effects (LMM, p> 0.05) and sNFL levels did not vary with time during SID or EID protocols (LMM, p> 0.05). Intra-individual sNFL levels demonstrated overall stability during SID and EID (median CV=11% between SID and EID samples). According to our previously published reference values, sNFL levels were in the normal range in all samples, both during SID and EID.

CONCLUSIONS

Our results suggest that sNFL quantification can be used as an alternative/additional approach to MRI in managing individual patients. The present work provides a new clinical application of sNFL to monitor NAT efficacy.