A total of 60 clinical trials have been conducted on 24 tau-directed therapeutics, and 13 trials are ongoing at the time of publication, with more likely to follow (Table 3), incorporating diverse mechanisms (Fig. 1). Tau represents an important target in the treatment of neurodegenerative disease, and the ultimate goal is to find a treatment that prevents the relentless progression of cognitive and motor symptoms. To this end, numerous hypotheses regarding tau biology are being tested in clinical trials for the first time, representing the dawn of a new age of drug development for tau, though numerous barriers remain to seeing a tau therapeutic in the clinic.
