MAPT and tauopathy: It is noteworthy that [3H]OXD-2115 showed high and similar affinities to the primarily 4R-tau (PSP, CBD) aggregates in vitro but had lower affinity to the predominantly 3R-tau aggregates in PiD, and [3H]OXD-2314 was expected to be similar, but instead showed high affinity for all of the non-AD and mixed 3 R/4R-tauopathies (AD) in human brain homogenate affinity assays (Table 2).