Biot,
I believe one likely scenario based on how Dr.M. has consistently planned ahead of the herd.
If he has strong clinical proof, objective evidence that A2-73 is effective and has a promising future however he must wait for the protocol to finish. He may then want to help the worst case CNS patients, in the universe of CNS patients I would argue FTD patients are on the short list, or with the most urgent need.
Would he wait or would he move on to help FTD patients now while understanding that is AVXL plan anyways? He would not wait (knowing A2-73 is already doing very well) he would move the help the most needy. IMO, that is why he has chosen to go forward early with FTD A3-71 initiatives. Why wait, if you already know the A2-73 outcome is positive. Act now to do the most good for the patient population. Also consider that FTD is about as bad an CNS disease as one can have and their clocks are running.