A drug can slow early Alzheimer's by up to 60 per cent in a breakthrough hailed as the 'turning point' in the fight against the disease.

In a 'defining moment' for dementia research, results from trials of donanemab found it significantly delayed the worsening of symptoms in people with this type of dementia.

It is the second treatment after lecanemab to offer hope to patients in what experts have hailed 'the decade of Alzheimer's', which could one day see it likened to other long-term conditions such as asthma or diabetes.

Scientists said it also ended the decades-long debate over whether the accumulation of sticky plaques, or amyloid, is at least partly responsible for the degenerative disease.