georgejjI, would you generally agree the following is true: The Exclusion Criteria below from the Anavex P2b/3 AD trial means that patients can be, and many will be, on an on-going treatment with a psychoactive medications e.g. Donepezil or one of the other Acetylcholine AD SOC drugs.
Being treated with psychoactive medications on a stable dose for less than 3 month.
The requirement is simply that a patient has been on a stable dose of the drug for 3 or more months prior to joining the Anavex trial. This should be an easily fulfilled requirement and likely easier than exclusively finding and enrolling patients not on any of the AD SOC drugs.
From the P2a Anavex AD trial peer reviewed paper, below is the actual percentage of patients co-administered Donepezil. It would be reasonable to assume a similar percentage (ca. 70%+) of P2b/3 patients across all arms of the P2b/3 trial are also on an on-going treatment with a psychoactive medications