MAPT and Alzheimer disease: This finding is in agreement withthe in vitro binding data in postmortem AD braintissue demonstrating two binding sites with IC50 valuesof 1 pM (58% of the binding sites) and 12 nM,39 as well as the in vivo PET studies.17,43 The selective binding of MK6240 to AD tau fibrils is well explainedby the unraveled atomistic interaction with two favorable sites inAD tau identified for MK6240.