Researchers from the biotechnology company Biogen have reported that a new drug reduced the amount of amyloid plaques—the brain deposits associated with dementia—and slowed cognitive decline in people with early Alzheimer’s disease. They presented the report March 20, 2015, at the International Conference on Alzheimer’s and Parkinson’s Diseases in Nice, France.
The researchers studied 166 people ages 50 to 90 who had been diagnosed with mild Alzheimer’s. The participants were randomly assigned to receive either a placebo or one of four different doses of the drug aducanumab—an antibody that attaches to amyloid deposits and turns the immune system on them.
The participants underwent brain scans and took tests of memory and reasoning ability when they entered the study and at six months and a year later. People who received the highest doses of the drug showed a reduction in amyloid deposits on the six-month scan, and an additional reduction on the second scan. There was no change in plaques in the placebo group. All of the participants did a little worse on the cognitive tests at six and 12 months than they had originally, but those receiving the three highest doses of the drug lost significantly less ground than those who got the placebo. The most common side effect was a headache, which was also related to the drug dose.
It’s important to note that this is an early study and that other promising dementia treatments have failed to have long-lasting effects when tested in larger numbers of people. Biogen is planning to enroll 1,000 people in a follow-up study.