Vaccine could prevent Alzheimer’s-inducing plaques

Researchers in California are working on a new vaccine that uses immunotherapy to prevent the formation of plaques believed to contribute to Alzheimer’s disease.

The vaccine is being tested by a team at the University of California San Diego’s School of Medicine and Alzheimer’s Disease Cooperative Study in the first clinical trial of its kind. Working with AC Immune of Switzerland, the UC San Diego researchers have developed a vaccine they believe may help block the buildup up of amyloids in the brain. Beta-amyloids are proteins believed to accumulate in the brain of individuals with Alzheimer’s disease, forming plaques-or abnormal clusters of protein fragments-that are toxic to nerve cells. The plaques block the transmission of nerve cell signals across the synapse, and may also trigger an inflammatory response that leads to inflammation and the destruction of disabled cells, according to the Alzheimer’s Association.

The vaccine (ACl-24) is being tested in individuals with Down syndrome, since they are 3 to 5 times more likely to develop Alzheimer’s disease than individuals without Down syndrome because chromosome 21-the gene responsible for causing Down syndrome-also regulates the expression of beta-amyloid. According to UC San Diego, individuals with Down syndrome who develop Alzheimer’s disease do so much earlier in life than other individuals, and nearly all individuals with Down syndrome develop beta-amyloid neuropathy by age 40.

The vaccine works by inducing antibodies against beta-amyloid, reducing accumulation in the brain and preventing inflammation. Earlier testing in animal models was promising, according to UC San Diego, and reveals strong antibody response plus improved memory capacity.

The clinical trial will involve 24 adults with Down syndrome between the ages of 35 and 45. They will receive treatment for 12 months, with 12 months of follow-up care. The study is being funded by the National Institutes of Health and the LuMind Research Down Syndrome Foundation.

“The human trial will focus on safety, tolerability and immunogenicity of the ACI-24 vaccine. Effects on cognitive function and biomarkers for Alzheimer’s disease will be secondary endpoints,” Michael Rafii, MD, PhD, principal investigator of the clinical trial and assistant professor of neurosciences who studies the links between Down syndrome and Alzheimer’s disease at UC San Diego, told Medical Economics.

Although only individuals with Down syndrome are taking part in the trial, researchers say the results could have far-reaching effects.

William Mobley, MD, PhD, chair of the Department of Neurosciences in the UC San Diego School of Medicine and executive director of the Down Syndrome Center for Research and Treatment, states in a press release about the vaccine that it may result in a way to modify progression of the disease through anti-amyloid intervention as well as provide insights about the efficacy and timing of such interventions when targeting sporadic Alzheimer’s disease in the general population.

Rafii says while early results are promising, it may be a long time before the vaccine is available to clinicians.

“This study aims to evaluate the safety and tolerability of a vaccine against beta amyloid in people with Down syndrome,” he says Rafii. “It is part of a longer process in Alzheimer’s disease therapeutic development. As with all therapies in development, it will need to go through additional studies before reaching the clinic or primary care physicians.”