Why the latest Alzheimer's 'cure' might be too good to be true

Eroding people’s memories and wearing down the body, Alzheimer’s is a particularly startling and upsetting disease both for sufferers and their loved ones. And as the world’s population ages at an unprecedented and enduring rate, experts are racing to find a cure for a condition which blights an increasing number of people in their twilight years.

Alzheimer’s is the most common form of dementia – an umbrella term used to describe degenerative diseases which currently affect 48million people across the world. With an estimated 135 million expected to be diagnosed with dementia by 2050, it is no wonder that half of adults in the UK fear it, according to a recent survey by the Alzheimer’s Society charity.

It is likely, then, that many welcomed the latest reports that a cure for Alzheimer’s could be just around the corner, to scrub the disease from the planet for once and for all. Currently, patients’ options are limited to treatments that reduce memory loss by replacing neurotransmitters eaten away by the condition. Now, researchers working in the US – where over $1.3 billion has already been spent on investigating dementia – believe that they have developed a “breakthrough” vaccine which uses the immune system’s antibodies to attack proteins believed to cause Alzheimer’s disease.

Following tests on mice, experts from the Institute for Molecular Medicine and the University of California, Irvine published a paper on a vaccine that targets both beta-amyloid and tau proteins linked to the disease. The former are often described as plaques in the brain, while tau are referred to as tangles: both are the focus of many other research studies which either attempt to clear them away or stop them forming altogether.

“If we are successful in pre-clinical trials, in three to five years we could be well on the way to one of the most important developments in recent medical history,” Flinders University School of Medicine Professor Nikolai Petrovsky, and co-author of the study published in Nature’s 'Scientific Reports' journal, recently said.

If the drug ever makes it to human trials, the team believes that both patients in the early stages of Alzheimer’s disease and people at risk of developing it could be treated with the vaccine.

It certainly sounds revolutionary – particularly to those desperately afraid of the disease. But experts working in a field where only 0.4 per cent of the almost 250 potential treatments for dementia tested between 2002 and 2012 have been successful are cautious to celebrate. Some even warn that harnessing the immune system against Alzheimer’s could be dangerous.

Dr Rosa Sancho, Head of Research at Alzheimer’s Research UK, welcomes the team’s two-pronged attack, and says that targeting both amyloid and tau could give more effective protection against the disease. Dr James Pickett, Head of Research at Alzheimer’s Society, meanwhile praises the team for taking innovative approach to solving problems associated with developing vaccines, including side-effects, but has warned the researchers to proceed with care as tests on mice do not fully replicate the brains of those with dementia.

Then there’s the elephant in the room. Research into a vaccine using the immune system to target amyloid and taus carried out by Ireland-based firm Elan were forced to halt in 2002, after 15 trial patients experienced potentially dangerous swelling of the central nervous system. And Professor Christian Holscher in Biomedical and Life Sciences at Lancaster University believes that vaccinating against amyloids and taus is an approach that should be abandoned altogether. “The vaccine theory has not shown any convincing effects so far,” he says. “The concept of using the immune system to treat Alzheimer’s disease is very dangerous, as it can induce auto-immune responses which are toxic.”

Researchers have been attempting to use antibodies to clear beta-amyloids from the brain for over a decade, he says, with a recent trial by pharmaceutical firm Eli Lilly showing only minor improvements in congintive tests but no improvements in daily living scores. “Therefore, this approach has been deemed a failure. As a result of this, any claim to the contrary will have to present very convincing data.” As for Professor Paul Morgan, Director of Systems Immunity Research Institute at Cardiff University, he doesn’t dismiss vaccines entirely - but is wary. “There is a long and tortuous history underlying attempts to use immunisation to reduce the burden of amyloid and or tau pathology in patients with Alzheimer's disease,” he says.

The study - which uses a combination of selecting sites targeted by tau and amyloids and awakening the immune system – is “interesting and promising”. But he says the results are at far too early a stage to have clinical significance of offer hope to patients. After all, he says, research papers hoping for results are all well and good, but at the end of the day “the proof is in the pudding."