Impact of serum neurofilament light on clinical decisions in a tertiary multiple sclerosis clinic.

Background and Objectives: Serum neurofilament light (sNfL) is a biomarker for neuro-axonal damage in multiple sclerosis (MS). Clinical implementation remains limited. We investigated the impact of implementation on clinical decisions using questionnaires at the MS Center Amsterdam, a tertiary outpatient clinic.
Methods: sNfL assessments were added to routine clinical practice (August 2021-December 2022). Before and after the results, clinicians filled in questionnaires on context of testing, clinical decisions, certainty herein, expectation of magnetic resonance imaging (MRI) activity, urgency, and motivation to receive the sNfL result and perceived value of sNfL.
Results: sNfL was assessed in 166 cases (age 41 ± 12 years, 68% female, 64% disease-modifying therapy (DMT) use) for the following contexts: "DMT monitoring" (55%), "new symptoms" (18%), "differential diagnosis" (17%), and "DMT baseline" (11%). Clinical decisions changed in 19.3% of cases post-disclosure, particularly in context "new symptoms" (38%) and with higher sNfL levels (β = 0.03, p = 0.04). Certainty increased ( p = 0.004), while expectation of MRI activity decreased with disclosure of low sNfL levels ( p = 0.01). Motivation was highest in context "differential diagnosis" ( p < 0.001); perceived value and urgency were highest in context "new symptoms" ( p = 0.02).
Conclusion: In this study, sNfL implementation had considerable impact on clinical decision-making and certainty herein. Standard implementation may complement patient care but warrants caution and more exploration in diverse clinical settings.
Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Z.Y.G.J.v.L., M.H.J.W., W.M.L.L., B.M., S.N.H., and L.H. report no disclosures. B.A.d.J. receives research support from Dutch MS Research Foundation, National MS Foundation, Dutch MS Association, and Zorgverzekeraars Nederland (i.e. umbrella organization of health insurers in the Netherlands). N.M., L.A.M., B.W.v.O., N.S., Z.L.E.v.K., L.V., M.J.W., and E.M.M.S. report no disclosures. B.M.J.U. reports consultancy fees from Immunic Therapeutics. J.K. received research grants for multicentre investigator-initiated trials DOT-MS trial, ClinicalTrials.gov Identifier: NCT04260711 (ZonMW), and BLOOMS trial (ZonMW and Treatmeds), ClinicalTrials.gov Identifier: NCT05296161; received consulting fees for F. Hoffmann-La Roche Ltd, Biogen, Teva, Merck, Novartis, and Sanofi/Genzyme (all payments to institution); reports speaker relationships with F. Hoffmann-La Roche Ltd, Biogen, Immunic, Teva, Merck, Novartis, and Sanofi/Genzyme (all payments to institution); adjudication committee of MS clinical trial of Immunic (payments to institution only). C.E.T. reports funding from National MS Society (Progressive MS alliance) and Innovative Medicines Initiatives 3TR (Horizon 2020, grant no. 831434); has a research contract with Celgene; serves on editorial boards of Medidact Neurologie/Springer, Neurology: Neuroimmunology and Neuroinflammation, and is an editor of a Neuromethods book Springer.