When put through tests, the vaccine helped cut levels of amyloid proteins by up to 50 per cent in certain areas of the brain. The proteins are thought to play a major role in the development and progress of the disease.
Over-production of amyloid proteins are thought to trigger symptoms of Alzheimer's by forming clumps that litter the brain.
In this latest study, Japanese scientists injected mice with DNA that codes for these proteins. The DNA has been designed so that it is not capable of replicating itself by incorporating itself into the human genome.
Normally scientists use a virus to transport the DNA into the cell. But in this way, a gentler immune response has been initiated.
The tests, conducted at the Tokyo Metropolitan Institute for Neuroscience, demonstrated that the latest vaccine reduced the deposition of amyloid proteins by between 15.5 per cent and 38.5 per cent compared with untreated mice.
Deposition in specific areas of the brain - the cerebral cortex and hippocampus - was reduced by 40-50 per cent.
The researchers suggest that DNA vaccines of the type they have produced could provide a cheap and effective strategy for treating Alzheimer's in future.
The findings support the idea that a vaccine is the best hope for fighting this disease for which there is currently no cure.
The class of drugs most commonly used to treat and prolong the symptoms of Alzheimer's is called acetylcholinesterase inhibitors (AchI). This market has been dominated by Pfizer's Aricept (donepezil), which holds over 50 per cent of the global market. Novartis's Exelon and Ortho-McNeil's Razadyne/Reminyl (galantamine) share the remainder.
The worldwide Alzheimer's disease therapeutics market is estimated to grow 11 per cent each year from $1.79bn (€1.41bn) in 2004 to approximately $3.05bn in 2009 and during this time AchIs will continue to dominate the market.
However, beyond this, their sales will suffer because of the expiry of their patents and the launch of new and combination products, such as the NMDA receptor antagonist recently launched by Forest's Namenda, and the availability of cutting edge disease-modifying therapies.
The Japanese study appears in the journal >Proceedings of the National Academy of Sciences.