Important bit:

In experiments on postmortem human brain tissue donated from patients with Alzheimer’s disease, dementia with Lewy bodies, and Pick’s disease (a form of frontotemporal dementia), the novel antibody medicine not only cleared away tau tangles but also stopped the release of ‘tau seeds’, which travel via connected neurons to tangle up proteins in other parts of the brain.

Many open questions remain, including whether this treatment delivered intranasally in humans will allow penetration of the antibody in effective doses throughout our much larger brains and whether there are any potentially dangerous side effects like inflammation, which is a concern in all of the amyloid-directed immunotherapy trials," write Meftah, Durrant, and Spires-Jones.