NEFL and Alzheimer disease: In Alzheimer’s disease, plasma NfL levels were monitored in both the TRAILBLAZER-ALZ randomized clinical trial for Donanemab and the phase 3 of the Clarity AD trial for lecanemab, with plasma NfL levels showing no significant changes or improvements when the treatment groups were compared to placebo.35,36 Interestingly, in the TRAILBLAZER-ALZ trial, plasma NfL was the only significant biomarker whose change from baseline negatively correlated to whole brain volume,35 perhaps suggestive that increasing NfL levels were reflective of passive release from brain atrophy during the trial duration.