NEFL and Alzheimer disease: However, this has not been reported to date with another anti-Tau active immunotherapy, AADVac1, which has an immunogen covering the N-terminal cysteinylated tau 294–305/4R region and showed preliminary evidence of slowing of neurodegeneration using plasma NfL, a non-specific fluid biomarker, and of AD-related decline in an post-hoc analysis from one clinical trial conducted in 196 participants with mild AD.30