Reader Response: Serum Neurofilament Light Association With Progression in Natalizumab-Treated Patients With Relapsing-Remitting Multiple Sclerosis

The results of the observational monocentric study by Bridel et al.(1) contrast with those from large phase 3 studies in progressive multiple sclerosis (MS) such as ASCEND, EXPAND, and INFORMS,(2,3) which suggest association of high baseline serum neurofilament light chain (sNfL) levels with increased risk of disability progression. In the accompanying editorial, Goldschmidt and Fox highlight that these earlier studies included a placebo arm where inflammation followed its natural course,(4) whereas Bridel et al.(1) studied patients on anti-inflammatory therapy by natalizumab. They hypothesized that the lack of association of sNfL with disability progression may result from suppression of inflammatory activity by natalizumab. They concluded that sNfL is not a valid biomarker for disease progression.

Automated summary

The results of this study contradict with earlier large phase 3 studies, suggesting that high baseline serum neurofilament light chain levels are associated with increased risk of disability progression in MS. The authors hypothesize that this discrepancy may be due to the anti-inflammatory effects of natalizumab, which suppresses inflammatory activity and renders sNfL unrelated to disability progression.