This is not true.... The initial trial was about dosing, by now they are on what the company believes is a therapeutic dose. We also don't know for sure that donepezil couteracts 2-73.
Remember though, maybe only 1/3 or 1/4 have been on 50mg. And, most the subjects are also taking donepezil, which counteracts 273
More accurately: They are all on their therapeutic MTD according to Missling, and donepezil is hypothesized by a few of us to thwart 2-73 binding to S1.