The research, published in the journal Neurology, proposes that monitoring the evolution of NfL, a biomarker of neuroaxonal damage, can complement current monitoring tools such as clinical evaluation and magnetic resonance imaging. This measurement could help identify biological disease activity in patients who appear to remain stable.
Neurofilament light is a structural protein released into the blood when neuronal damage occurs. In multiple sclerosis, its levels increase during inflammatory episodes and tend to decrease with effective treatments. Persistently elevated levels have been linked to increased future disease activity and disability accumulation. The study uses a standardized score (z-score) to compare levels with healthy individuals and track individual evolution.
Analysis of patients with relapsing-remitting multiple sclerosis treated with various disease-modifying therapies revealed that those whose NfL levels did not decrease after one year were approximately three times more likely to experience disease activity in the second year. This association was stronger in patients without prior treatment.
A notable finding was that, even in patients meeting NEDA-3 criteria (no new relapses, disability progression, or MRI activity), the lack of NfL reduction was also associated with a higher risk of future activity. Dr. Georgina Arrambide, a neurologist at Cemcat and lead researcher, notes that NfL monitoring provides an "additional dimension" and can help identify patients requiring closer monitoring earlier.
While MRI remains essential, NfL monitoring could refine the identification of high-risk patients without replacing existing tools. An unexpected increase or lack of NfL reduction might suggest the need for an additional MRI scan.
The authors acknowledge limitations, including NfL change's moderate ability to predict future activity (area under the curve of approximately 0.63) and that the association did not hold for predicting activity in the third year. Therefore, NfL is considered a complementary tool, not an isolated one, for therapeutic decisions, contributing to more personalized multiple sclerosis monitoring.
