Researchers in the US and Australia have developed a vaccine formulation which targets two of the key proteins involved in Alzheimer’s disease progression. According to Professor Nikolai Petrovsky, of Flinders University School of Medicine in Australia and his colleagues on the study, the vaccine could enter clinical trials in the next three to five years.
In preclinical trials, the combination vaccine was able to stimulate the immune system to produce antibodies against both beta-amyloid and tau proteins in the brain. High levels of both of these proteins are commonly found in the brains of people with Alzheimer’s disease.
Beta-amyloid accumulation resulting in plaque formation occurs in the extracellular space surrounding neurons, whereas the tau protein forms primarily intracellular tangles. These plaques and tangles likely interfere with the normal cell-to-cell signaling between nerve cells, which leads to cell death and further neurodegeneration.
“[The proteins are] a bit like the car in your driveway,” Petrovsky told ABC Adelaide. “You need to remove them from the brain otherwise if you left broken down cars in your driveway eventually you couldn’t get out.
“Essentially that’s what happens in people who get Alzheimer’s or dementia is they have lots of these broken down proteins in the brain,” Petrovsky continued. The results of their research on a candidate Alzheimer’s vaccine were published in the journal, Scientific Reports.
Using the MultiTEP vaccine platform and Advax, Petrovsky and his colleagues developed their Alzheimer’s vaccine candidate. The MultiTEP technology triggers a strong antibody response to both the beta-amyloid and tau proteins, while the adjuvant vaccine Advax strengthens the overall immune response.
The researchers found that this combination formula was highly-effective and well tolerated in mouse models of Alzheimer’s disease. What’s more, the vaccine was able to generate an immune response against the Alzheimer’s-associated proteins in brain tissue, harvested from patients with the neurodegenerative disease.
“This study suggests that we can immunize patients at the early stages of AD [Alzheimer’s disease], or even healthy people at risk for AD, using our anti-amyloid-beta vaccine, and, if the disease progresses, then vaccinate with another anti-tau vaccine to increase effectiveness,” said Professor Michael Agadjanyan, Institute for Molecular Medicine, California. The researchers benefited from funding provided by the National Institutes of Health (NIH), which will provide $1.3 billion in total funding for Alzheimer’s research this year alone.
Clinical trials for Alzheimer’s drugs are notoriously difficult, with only a 0.4 percent success rate for drugs which made it through to regulatory approval between 2002 and 2012. Approximately 5.4 million people in the US have been diagnosed with Alzheimer’s disease, and this number is predicted to grow three-fold by 2050.