Promising Alzheimer's vaccine draws closer to human trials, researchers say

A DNA vaccine shown to reduce the accumulation of toxic proteins associated with Alzheimer’s disease in mice could be moving closer to human trial, according to researchers University of Texas Southwestern Medical Center.

A team with the center's Peter O'Donnell Jr. Brain Institute tested the vaccine, which researchers say prompts an immune response that reduces the build-up of toxic tau and beta-amyloid proteins. Their findings were published this week in the medical journal Alzheimer's Research and Therapy.

“This study is the culmination of a decade of research that has repeatedly demonstrated that this vaccine can effectively and safely target in animal models what we think may cause Alzheimer’s disease,” Dr. Roger Rosenburg, founding director of the Alzheimer’s Disease Center at UT Southwestern, said in a news release. “I believe we’re getting close to testing this therapy in people.”

The vaccine is delivered to the skin and appears to be safe for humans, researchers said. It had previously been tested -- with similar results -- in monkeys and rabbits.

The study published this week included tests on four cohorts composed of between 15 and 24 mice each. It showed that the DNA vaccine developed by Rosenberg and his team "prompted a 40 percent reduction in beta-amyloid and up to a 50 percent reduction in tau, with no adverse immune response," according to UT Southwestern.

No effective treatment currently exists for Alzheimer's, the most common type of dementia. The disease often presents initially with mild memory loss and can progress to the point where it seriously affect's a person's ability to complete day-to-day activities, according to the Centers for Disease Control and Prevention.

As many as 5 million Americans were living with the disease in 2014, the last year for which data was available, according to the CDC. Younger people sometimes get Alzheimer’s, but symptoms often appear after age 60, the agency reported.

“If the onset of the disease could be delayed by even five years, that would be enormous for patients and their families,” Dr. Doris Lambracht-Washington, the study’s senior author, said in a news release. “The number of dementia cases could drop by half.”

Several other therapies are also being researched and tested to treat the disease.