It has been previously shown that the neuronal cytoskeletal protein neurofilament light chain (NfL) is released into the blood and cerebrospinal fluid (CSF) upon neuroaxonal injury.1 Hence it was not surprising that recent studies found that serum NfL levels are associated with disease activity and treatment response in multiple sclerosis (MS). However, the ability of serum NfL levels to identify patients who are on established disease-modifying treatments (DMTs) and have suboptimal treatment responses has never been confirmed. During this year’s “2020 joint ACTRIMS/ECTRIMS meeting”, Özgür Yaldizli (Department Neurology, University Hospital Basel, Switzerland) presented a real‑world cohort study on the value of serum NfL levels as a biomarker to predict treatment responses in MS patients.
A Swiss cohort to determine biomarker value
Dr Yaldizli and his colleagues tried to answer their research question with data from the Swiss MS cohort study participants (N=1366), who are being followed up with serum sampling every 6 or 12 months. To be able to determine the treatment‑related prognostic value of serum NfL, the researchers only included patients on DMTs for at least 3 months. The median follow-up time at the time of analysis was 4.9 years.
Previous findings confirmed
The researchers found that there was a stable association between serum NfL levels and clinical and magnetic resonance imaging (MRI) measures, as previously found in numerous studies. In addition, they could see that a large number of serum samples from MS patients showed elevated serum NfL levels compared to those from a healthy control group.
Serum NfL Z-scores predicted relapse or EDSS worsening
Besides confirming published data, Dr Yaldizli and his colleagues found some more interesting correlations. “We compared serum NfL values with healthy control data using Z-scores. These reflect the deviation of a patient’s serum NfL levels from the mean value of the same age healthy controls.” In their study, the serum NfL Z-score predicted relapse, measured by the Expanded Disability Status Scale (EDSS) score, in the year after its assessment. “The higher the NfL Z-score is, the higher is the risk of relapse or EDSS worsening in the following year. The same is true for MRI outcomes”, the scientist stated during his presentation. Serum NfL Z-scores were also able to predict new or enlarging T2 lesions determined by MRI in the subsequent year.
Great clinical value of serum NfL levels
The previously published data have already looked very promising, and Dr Yaldizli’s data add further value to the use of serum NfL levels as a biomarker in MS. “Our data in this well characterised, large, real-world cohort support the value of serum NfL levels for treatment monitoring in MS clinical practice”, the author stated as a conclusive remark.
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