Were still improved is not the same as still improving.
According to the study I have linked the improvement in ADAS-cog scores occurred in the first 3 to 6 weeks of treatment. After that there was a decline at a reduced rate compared to placebo.
Show us a trial in which a significant number of participants with Alzheimer's disease and taking a placebo improved over a period of 48 weeks or longer
Placebo Definition: A substance that has no therapeutic effect, used as a control in testing new drugs.
The Anavex Phase 2b/3 trial for the treatment of early stage Alzheimer's disease with Blarcamesine will compare the response of the two Blarcamesine cohorts (50 mg per day and 30 mg per day) to a placebo cohort.