Neurology, Neuroimmunology & Neuronflammation | April 26, 2021

Fissolo N, Pignolet B, Rio J, Vermersch P, Ruet A, deSèze J, Labauge P, Vukusic S, Papeix C, Martinez-Almoyna L, Tourbah A, Clavelou P, Moreau T, Pelletier J, Lebrun-Frenay C, Bourre B, Defer G, Montalban X, Brassat D and Comabella M

Neurol Neuroimmunol Neuroinflamm Jul 2021, 8 (4) e1003

DOI: https://doi.org/10.1212/NXI.0000000000001003

Abstract

Objectives The study aimed to assess the potential for serum neurofilament light chain (NFL) levels to predict the risk of progressive multifocal leukoencephalopathy (PML) in natalizumab (NTZ)-treated patients with multiple sclerosis (MS) and to discriminate PML from MS relapses.

Methods NFL levels were measured with single molecule array (Simoa) in 4 cohorts: (1) a prospective cohort of patients with MS who developed PML under NTZ therapy (pre-PML) and non-PML NTZ-treated patients (NTZ-ctr); (2) a cohort of patients whose blood was collected during PML; (3) an independent cohort of non-PML NTZ-treated patients with serum NFL determinations at 2 years (replication cohort); and (4) a cohort of patients whose blood was collected during exacerbations.

Results Serum NFL levels were significantly increased after 2 years of NTZ treatment in pre-PML patients compared with NTZ-ctr. The prognostic performance of serum NFL levels to predict PML development at 2 years was similar in the NTZ-ctr group and replication cohort. Serum NFL levels also distinguished PML from MS relapses and were 8-fold higher during PML compared with relapses.

Conclusions These results support the use of serum NFL levels in clinical practice to identify patients with relapsing-remitting MS at higher PML risk and to differentiate PML from clinical relapses in NTZ-treated patients.

Classification of Evidence This study provides Class I evidence that serum NFL levels can identify NTZ-treated patients with MS who will develop PML with a sensitivity of 67% and specificity of 80%.

This study was performed using the Quanterix HD-1 Analyzer.