The use of neurofilament light chain (NfL) as a biomarker could revolutionise clinical trials
in progressive MS.

One of the hurdles to developing treatments for progressive MS is the lack of a reliable and easy way to measure progression. In other words, a suitable way to measure whether a potential medication is working. Clinical trials involving people with relapsing MS often rely on counting relapses or MRI-detected lesions to track MS activity. However, progression is less easily measured, and usually happens over longer periods of time. This makes it hard to quickly detect whether a therapy is slowing or stopping progression in clinical trials; a serious roadblock for developing therapies for progressive MS.

Having objective indicators that detect progression, measure treatment impact, and predict an individual’s course and response to therapy would speed the development of new therapies and improve care for people with progressive MS. One potential measure is a biomarker called “neurofilament light” (NfL). Biomarker is short for biological marker, which is any measurable indicator of a biological process. In this context we need a biomarker of disease progression which can be readily measured, for example from a blood test.


Neurofilaments are proteins found in nerve fibres that are necessary for the proper conduction of electrical impulses by nerves. NfL is a fragment of the neurofilament protein and it enters the spinal fluid and blood when nerves are damaged by MS or other causes. Recent technological advances means that we can now detect NfL in the blood (serum and plasma), and not just in spinal fluid obtained by lumbar puncture, making it much more convenient and practical as a potential biomarker.

Studies of NfL in serum, plasma and spinal fluid have been underway to better define how this biomarker could be used to help detect and predict disease activity, progression, and response to treatments in MS and other neurological conditions. NfL is also detected in healthy individuals, and increases with age, so it is important to understand what is normal and what is not.

The outcomes

The International Progressive MS Alliance convened a panel of experts, to consider the current state of research on fluid biomarkers in MS in general and progressive MS specifically. The expert panel, made up of people affected by MS, scientists, and MS clinicians aims to mobilise the MS community toward filling key gaps in knowledge and understanding about NfL. The panel, has now published a paper in the scientific journal Neurology that summarises what is known about NfL as a potential biomarker. They have also made recommendations for further research to refine the potential of NfL to predict disease course and detect response to therapy in progressive MS.

These include:

  • Making a standard protocol around how NfL should be measured so that findings can be compared across multiple studies.
  •  Establishing what “normal” NfL values are in people of different ages and with and without known medical conditions, and potential confounding factors such as smoking; a critical next step.
  • Reanalysing prior clinical trial data to further understand whether serum NfL levels accurately predict future disease activity and progression, how they correspond with MRI findings, and how they are influenced by disease activity and various therapies.

If NfL proves to be a reliable biomarker, this would revolutionise clinical trials in progressive MS. The International Progressive Multiple Sclerosis Alliance and its partners, will continue to advance these initiatives to support their goal of speeding the development of therapies for the progressive forms of MS.

About the International Progressive MS Alliance

The Alliance exists to accelerate the development of effective treatments for people with progressive forms of MS to improve quality of life worldwide. It is an unprecedented global collaboration of 19 MS organisations, researchers, health professionals, the pharmaceutical industry, companies, trusts, foundations, donors and people affected by progressive MS, working together to address the unmet needs of people with progressive MS ─ rallying the global community to find solutions. Our promise is
more than hope, it is progress.

With thanks to MS Research Australia for providing this research summary.