When I looked at their trials some time ago, I concluded LLY has better trial results than Adhelm with the amyloid hypothesis, and they will prove that you can slow the decline in some patients, with that approach.
Their are reasons that the FDA granted BIIB approval, and I believe it was based in part on FDA information about potential benifits of clearing some parts of the amyloid cascade. Not all amyloid is the same.
BIIB has another drug focused on this approach that may work better than Adhelm which also merits attention.