Study Finds Experimental Alzheimer’s Drug Slows Cognitive Decline

A large clinical trial of Eli Lilly’s experimental Alzheimer’s medication, donanemab, found the drug slowed declines in patients’ ability to think clearly and perform daily tasks by more than a third. The drug, which is given by infusion once a month, works by removing plaque buildups in the brain known as amyloid that are a hallmark of Alzheimer’s disease. In the trial, donanemab cleared amyloid so effectively that a majority of patients in the trial — 52 percent — were able to stop taking the medicine by one year, and 72 percent were able to do so by a year and a half.

In the trial that ran for 18 months and included 1,700 patients, researchers looked at the participants in two groups, separated by levels of a brain protein known as tau. A 35 percent slowing in cognitive and functional decline was seen in the group with intermediate levels of tau, whose disease hadn’t progressed as far. When this intermediate group was combined with the group with higher levels of tau, the figure was 22 percent. However, there were some side effects reported; there were three deaths in the trial among people taking the drug, two of which were attributed to adverse events such as brain swelling or microhemorrhages, known as amyloid-related imaging abnormalities.

“For every medicine, for every disease, there are potential risks and potential benefits,” said Eli Lilly’s Chief Scientific and Medical Officer Daniel Skovronsky, MD, PhD. But he noted that almost half of the participants taking the drug, 47 percent, showed no decline on a key measure of cognition over the course of a year, compared with 29 percent of people taking a placebo. “That’s “the kind of efficacy that’s never been seen before in Alzheimer’s disease,” said Dr. Skovronsky.

Eli Lilly filed for accelerated approval with the U.S. Food and Drug Administration (FDA) for donanemab based on earlier results but was rejected in January as the agency sought more data. Based on these results, in people with early symptomatic Alzheimer’s disease, Eli Lilly says it plans to file for approval from FDA by the end of June.