I think the biggest change is the demotion of measurements of functional effect of the drug.
[M]any of the assessment tools typically used to measure functional impairment in patients with later dementia stages of AD (Stages 4 through 6) would not be sensitive to detect subtle functional changes in early AD. Therefore, FDA may consider other approaches, including endpoints based on cognitive assessments or surrogate endpoints, which may allow for shorter trial durations as a basis for approval in the earliest stages of AD (i.e., Stages 1, 2, and early 3).
The P2b/3's biggest weakness was with functional efficacy, specifically the ADCS-ADL results. The trial's subjects were pretty much all in Stages 2 and 3 as far as I can tell. I read this as saying ADL results will no longer be a hindrance.
Additionally, the draft shows great openness to relevant AD biomarkers, and looks to having more of them than just amyloid. I'd be very surprised if the FDA would not look very favorably on blarcamesine's effect on brain volume; it seems the type of additional biomarker the FDA would be looking for under this new draft guidance.
Even though it's not final, I think this draft almost certainly indicates the direction the FDA is heading with regard to evaluating clinical trial results for Alzheimer's disease. I think it bodes very well for blarcamesine's chances.