Sharmilee Gnanapavan

Is it time to target no evident disease activity (NEDA) in multiple sclerosis

The management of multiple sclerosis is becoming increasingly complex with the emergence of new and more effective disease-modifying therapies (DMT). We propose a new treatment paradigm that individualises treatment based on a choice between two interchangeable therapeutic strategies of maintenance-escalation or induction therapy. We propose treating- to-target of no evident disease activity (NEDA) as defined using clinical and MRI criteria. This algorithm requires active monitoring with a rebaselining MRI, at a point in time after the specific DMT concerned has had sufficient time to work, and at least annual MRI studies to monitor for subclinical relapses. Disease activity on the maintenance-escalation therapy arm of the algorithm indicates a sub-optimal treatment response and should trigger a discussion about switching, or escalating, therapy or the consideration of switching to the induction therapy arm of the algorithm. In comparison, disease activity on an induction therapy arm would be an indication for retreatment or a switch to the maintenance-escalation therapy arm. We envisage the definition of NEDA evolving with time as new technological innovations are adopted into clinical practice, for example the normalisation of whole, or regional, brain atrophy rates and cerebrospinal fluid neurofilament levels.

Consensus definitions and application guidelines for control groups in cerebrospinal fluid biomarker studies in multiple sclerosis.

The choice of appropriate control group(s) is critical in cerebrospinal fluid (CSF) biomarker research in multiple sclerosis (MS). There is a lack of definitions and nomenclature of different control groups and a rationalized application of different control groups. We here propose consensus definitions and nomenclature for the following groups: healthy controls (HCs), spinal anesthesia subjects (SASs), inflammatory neurological disease controls (INDCs), peripheral inflammatory neurological disease controls (PINDCs), non-inflammatory neurological controls (NINDCs), symptomatic controls (SCs). Furthermore, we discuss the application of these control groups in specific study designs, such as for diagnostic biomarker studies, prognostic biomarker studies and therapeutic response studies. Application of these uniform definitions will lead to better comparability of biomarker studies and optimal use of available resources. This will lead to improved quality of CSF biomarker research in MS and related disorders.

Biomarker Report from the Phase II Lamotrigine Trial in Secondary Progressive MS – Neurofilament as a Surrogate of Disease Progression

Objective Lamotrigine trial in SPMS was a randomised control trial to assess whether partial blockade of sodium channels has a neuroprotective effect. The current study was an additional study to investigate the value of neurofilament (NfH) and other biomarkers in predicting prognosis and/or response to treatment. Methods SPMS patients who attended the NHNN or the Royal Free Hospital, UK, eligible for inclusion were invited to participate in the biomarker study. Primary outcome was whether lamotrigine would significantly reduce detectable serum NfH at 0-12, 12–24 and 0–24 months compared to placebo. Other serum/plasma and CSF biomarkers were also explored. Results Treatment effect by comparing absolute changes in NfH between the lamotrigine and placebo group showed no difference, however based on serum lamotrigine adherence there was significant decline in NfH (NfH 12–24 months p = 0.043, Nfh 0–24 months p = 0.023). Serum NfH correlated with disability: walking times, 9-HPT (non-dominant hand), PASAT, z-score, MSIS-29 (psychological) and EDSS and MRI cerebral atrophy and MTR. Other biomarkers explored in this study were not found to be significantly associated, aside from that of plasma osteopontin. Conclusions The relations between NfH and clinical scores of disability and MRI measures of atrophy and disease burden support NfH being a potential surrogate endpoint complementing MRI in neuroprotective trials and sample sizes for such trials are presented here. We did not observe a reduction in NfH levels between the Lamotrigine and placebo arms, however, the reduction in serum NfH levels based on lamotrigine adherence points to a possible neuroprotective effect of lamotrigine on axonal degeneration.

Serum neurofilament is associated with progression of brain atrophy and disability in early MS

Objective: To investigate a potential effect of riluzole on serum neurofilaments (Nf) compared to placebo and the relationship between longitudinal clinical and MRI outcomes and serum Nf levels. Methods: Serum samples were obtained from participants enrolled in a randomized double-blind trial of neuroprotection with riluzole vs placebo as an add-on to weekly interferon-β (IFN-β)–1a IM initiated 3 months after randomization. Nf measurements were performed by ELISA and electrochemiluminescence immunoassay. Results: Longitudinal serum samples were available from 22 riluzole and 20 placebo participants over 24 months. There was no observed treatment effect with riluzole. Nf light chain (NfL) levels decreased over time (p = 0.007 at 24 months), whereas the Nf heavy chain was unchanged (p = 0.997). Changes in NfL were correlated with EDSS change (p = 0.009) and neuropsychological outcomes. Brain volume decreased more rapidly in patients with high baseline NfL (p = 0.05 at 12 months and p = 0.008 at 24 months) and this relationship became stronger at 24 months (p = 0.024 for interaction). Higher and increasing NfL predicted higher number of gadolinium-enhancing lesions (p < 0.001 for both). Conclusions: Our findings support the potential value of serum NfL as a marker of neuroaxonal injury in early multiple sclerosis. Its reduction over time could represent regression to the mean, or a possible treatment effect of IFN-β-1a. The association with whole brain atrophy and the formation of acute white matter lesions has relevant implications to use serum NfL as a noninvasive biomarker of the overall consequences of brain damage and ongoing disease activity. ClinicalTrials.gov identifier: NCT00501943.

Development of protein biomarkers in cerebrospinal fluid for secondary progressive multiple sclerosis using selected reaction monitoring mass spectrometry (SRM-MS)

BackgroundMultiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS). It involves damage to the myelin sheath surrounding axons and to the axons themselves. MS most often presents with a series of relapses and remissions but then evolves over a variable period of time into a slowly progressive form of neurological dysfunction termed secondary progressive MS (SPMS). The reasons for this change in clinical presentation are unclear. The absence of a diagnostic marker means that there is a lag time of several years before the diagnosis of SPMS can be established. At the same time, understanding the mechanisms that underlie SPMS is critical to the development of rational therapies for this untreatable stage of the disease.ResultsUsing high performance liquid chromatography-coupled mass spectrometry (HPLC); we have established a highly specific and sensitive selected reaction monitoring (SRM) assay. Our multiplexed SRM assay has facilitated the simultaneous detection of surrogate peptides originating from 26 proteins present in cerebrospinal fluid (CSF). Protein levels in CSF were generally ~200-fold lower than that in human sera. A limit of detection (LOD) was determined to be as low as one femtomol. We processed and analysed CSF samples from a total of 22 patients with SPMS, 7 patients with SPMS treated with lamotrigine, 12 patients with non-inflammatory neurological disorders (NIND) and 10 healthy controls (HC) for the levels of these 26 selected potential protein biomarkers. Our SRM data found one protein showing significant difference between SPMS and HC, three proteins differing between SPMS and NIND, two proteins between NIND and HC, and 11 protein biomarkers showing significant difference between a lamotrigine-treated and untreated SPMS group. Principal component analysis (PCA) revealed that these 26 proteins were correlated, and could be represented by four principal components. Overall, we established an efficient platform to develop and verify protein biomarkers in CSF, which can be easily adapted to other proteins of interest related to neurodegenerative diseases.ConclusionsA highly specific and sensitive multiplex SRM-MS assay was established for development and verification of CSF protein biomarkers in SPMS. Five proteins were found to be expressed significantly differently between the three cohorts, SPMS, NIND and HC and 11 proteins associated with lamotrigine treatment, which we expect will further our current understanding of SPMS disease pathology and/or therapeutic intervention.

Neural cell adhesion molecule — Description of a CSF ELISA method and evidence of reduced levels in selected neurological disorders

Neural cell adhesion molecule (NCAM) is important for neuronal growth and repair. Here we describe the development and validation of a sensitive ELISA for NCAM using commercially available reagents. The measurable range of NCAM ELISA is 16-500 ng/mL, with a constant coefficient-of variation and good parallelism between the reference standard curve and CSF. CSF NCAM was measured in 36 benign-intracranial hypertension, 51 multiple sclerosis, 27 neuropathy, 37 Alzheimers disease, 12 cognitive impairment, 15 motoneurone disease, 13 meningitis, 17 encephalitis, and 17 control cases. Significant reductions were found between controls and multiple sclerosis, Alzheimers disease and meningitis.

Consensus guidelines for lumbar puncture in patients with neurological diseases.

Cerebrospinal fluid collection by lumbar puncture (LP) is performed in the diagnostic workup of several neurological brain diseases. Reluctance to perform the procedure is among others due to a lack of standards and guidelines to minimize the risk of complications, such as post‐LP headache or back pain.

Neurofilament light antibodies in serum reflect response to natalizumab treatment in multiple sclerosis

Background: Increased levels of antibodies to neurofilament light protein (NF-L) in biological fluids have been found to reflect neuroinflammatory responses and neurodegeneration in multiple sclerosis (MS). Objective: To evaluate whether levels of serum antibodies against NF-L correlate with clinical variants and treatment response in MS. Methods: The autoantibody reactivity to NF-L protein was tested in serum samples from patients with relapsing–remitting MS (RRMS) (n=22) and secondary progressive MS (SPMS) (n=26). Two other cohorts of RRMS patients under treatment with natalizumab were analysed cross-sectionally (n=16) and longitudinally (n=24). The follow-up samples were taken at 6, 12, 18 and 24 months after treatment, and the NF-L antibody levels were compared against baseline levels. Results: NF-L antibodies were higher in MS clinical groups than healthy controls and in RRMS compared to SPMS patients (p<0.001). NF-L antibody levels were lower in natalizumab treated than in untreated patients (p<0.001). In the longitudinal series, NF-L antibody levels decreased over time and a significant difference was found following 24 months of treatment compared with baseline measurements (p=0.001). Conclusions: Drug efficacy in MS treatment indicates the potential use of monitoring the content of antibodies against the NF-L chain as a predictive biomarker of treatment response in MS.

Switching patients at high risk of PML from natalizumab to another disease-modifying therapy

There are several options for switching people with multiple sclerosis (MS) who are at high risk of developing progressive multifocal leukoencephalopathy (PML) from natalizumab to alemtuzumab. However, some of these have risks that need to be managed, for example, the risks of carrying over asymptomatic PML from natalizumab on to the new therapy, and the risk of rebound disease activity associated with a prolonged washout after starting natalizumab. We propose a pragmatic bridging strategy, using another disease-modifying therapy (DMT), to reduce the risk of switching from natalizumab to alemtuzumab. We also discuss the caveats and subtleties associated with sequencing DMTs in MS and the complex decision making involved.

Neural cell adhesion molecules in brain plasticity and disease

Neural cell adhesion molecule (NCAM) has been studied extensively. But it is only in recent times that interest in this molecule has shifted to conditions such as Alzheimers disease, Multiple Sclerosis and Schizophrenia, focusing on its role in neurodegeneration and abnormal neurodevelopment. NCAM is important in neurite outgrowth, long-term potentiation in the hippocampus and synaptic plasticity. Reduced as well as increased levels in NCAM have been linked to pathology in the brain suggesting that a shift in the equilibrium may be the key. Hence, increasing our understanding of the role of NCAM in health and disease should clear some of the ambiguity surrounding the molecule and even lead to newer potential therapeutic targets. This review consolidates our current understanding of NCAM, focusing on the consequences of dysregulation, its role in neurodegenerative and neurodevelopmental disorders, and the future of NCAM plus potential options for therapy.