MAPT and Alzheimer disease: Several tau-lowering approaches have now entered early clinical development, including antisense oligonucleotides (ASOs) targeting MAPT mRNA (e.g., BIIB080/IONIS-MAPTRx, phase 1b/2a) and tau-directed monoclonal antibodies for PSP and AD, indicating that tau reduction is clinically feasible, although long-term safety and efficacy still remain to be established.