Trials for four new Alzheimer's drugs could bring hope to thousands of sufferers.
The four drugs, namely anti-amyloid Alzhemed, brain cell death-inhibiting Dimebon, an Alzheimer's 'vaccine' and a diabetes medication called Avandia, have been undergoing tests for their long-term benefits.
Dimebon appears to offer protection from amyloid build-up, but many participants dropped out of the trial due to side-effects.
The Alzheimer's 'vaccine' led to participants showing slower rates of decline in their daily lives, but was associated with brain-swelling.
Avandia was found to have an impact on the inflammation of the brain, but has been linked to an increased risk of heart attack.
Current treatments simply relieve the symptoms for couple of years, after which the disease sets in, but these medications could offer more hope to sufferers.
Dr Sam Gandy, chair of the Alzheimer's Association's Medical and Scientific Advisory Council in the US, said: "The odds are quite good that we'll have more effective new treatments for Alzheimer's in the near future.
"We have learned important lessons about how to do these types of very complex, long-term, large-scale Alzheimer's trials, which in itself is very important because there are now so many promising Alzheimer's therapies in the pipeline."