Different dementia rating scales may give different results because the study is underpowered for the effect, and/or Aducanumab is only effective in a subset of

Different dementia rating scales may give different results because the study is underpowered for the effect, and/or Aducanumab is only effective in a subset of patients. There is something to suggest that the latter is the case. The MMSE score usually becomes low relatively late in dementia. The questions are easily solvable for most non-affected people [1] and the cognitive impairment must be quite severe for a significant drop. ADAS-COG on the other hand is more sensitive, especially in early disease [2]. It would be plausible then that patients in an early dementia stage treated with a higher dose, respond, while patients in a later disease stage can not be treated using Aducanumab. (Maybe it even has a paradoxical detrimental effect in late-stage dementia, who knows?) I would hope that they dig down in the data and find an objectively identifiable subpopulation where there appears to be significant effect, and rerun a phase III trial on that subgroup. Even if they only can treat a subset of Alzheimer patients, that's a very significant breakthrough. [1] https://www.bgs.org.uk/sites/default/files/content/attachment/2018-07-05/mini-mental_state_exam.pdf https://www.bgs.org.uk/sites/default/files/content/attachmen... [2] https://www.ncbi.nlm.nih.gov/pubmed/12079572 https://www.ncbi.nlm.nih.gov/pubmed/12079572