Background

Serum neurofilament light chain (sNfL) levels are a promising biomarker for quantifying neuro-axonal injury in multiple sclerosis (MS). Recent studies showed sNfL levels relate to disease activity and treatment response.

Objectives

To analyze the predictive capacity of baseline (BL) sNfL levels for disease outcomes in the 15-year BENEFIT study long-term follow-up

Methods

Monofactorial regression analyses were conducted on outcomes at Year 15, including sNfL age-adjusted percentiles (80^th, 90^th, 95^th, 97.5^th and 99^th; Disanto et al., 2017).

Further BL covariates included sex; age; lowest EDSS up to Month 6; mono/multifocal onset; presence of optic nerve, brainstem, or spinal cord lesions; Paced Auditory Serial Addition Test 3 (PASAT-3), Timed 25 Foot Walk (T25W), and 9 Hole PEG test (9HPT) scores; number/volume of hypointense T1, gadolinium-enhancing T1, and T2 lesions; cerebral volume; and initial treatment assignment. On-study covariates at Years 1, 2, and 5 were annualized relapse rate; EDSS change; PASAT-3, T25W, and 9HPT scores; annualized rate of new lesions; lesion number/volume; brain volume change; and relative duration of treatment. Covariates with p≤0.1 (at ≥2 time points for on-study covariates) were entered into multifactorial models.

We assessed the predictive capacity of BL sNfL levels for the following outcomes: EDSS ≥4, clinically silent disease, T2 lesion volume, and cerebral volume.

Results

Patients with sNfL values at screening (N=258) above the 90^th (n=176), 95^th (n=157), 97.5^th (n=149), and 99^th (n=129) percentiles (adjusted for other relevant covariates) had a significantly higher risk of EDSS≥4 at Year 15 for BL model (odds ratio 2.45 [95% CI: 1.05,5.68] p=0.0376; 2.60 [1.18,5.75] p=0.0181; 2.61 [1.20,5.66] p=0.0154; 2.47 [1.19,5.13] p=0.0150, for the 90^th, 95^th, 97.5^th and 99^th percentiles, respectively), and for on-study models at Year 1 (3.86 [1.16,12.78] p=0.0272; 3.38 [1.13,10.14] p=0.0296; 2.92 [1.02,8.35] p=0.0461; 2.98 [1.11,8.00] p=0.0305, respectively) and Year 2 (5.36 [1.26,22.85] p=0.0231; 4.88 [1.34,17.77] p=0.0163; 3.86 [1.18,12.66] p=0.0259; 3.34 [1.17,9.48] p=0.0237, respectively). Covariates that remained statistically significant with EDSS≥4 as the endpoint in most percentile models were lowest EDSS value up to Month 6 for BL and Year 1, and change in brain volume at Year 1, 2, and 5.

Conclusions

Findings in this unique long-term BENEFIT study suggest that higher sNfL values in early MS disease stages are independent predictors of long-term disability.