Alzheimer drug shows results, with risks
SAN FRANCISCO — An experimental Alzheimer’s drug from Eisai and Biogen slowed cognitive decline in a closely watched trial, but may carry a risk of serious side effects for certain patients, according to detailed data presented on Tuesday.
The drug, lecanemab, was associated with a dangerous type of brain swelling in nearly 13 percent of patients in the trial that spanned 18 months and enrolled nearly 1,800 participants with early-stage Alzheimer’s.
Some patients also experienced bleeding in the brain, with five experiencing macrohemorrhages and 14 percent having microhemorrhages — a symptom linked to two deaths of people receiving the drug in a follow-on study.
The two deaths were among lecanemab users who were also taking blood-thinning medications for other health problems. Eisai said on Tuesday that the deaths cannot be attributed to the Alzheimer’s drug.
The companies said in September that lecanemab — an antibody designed to remove sticky deposits of a protein called amyloid beta — reduced the rate of cognitive decline on a clinical dementia scale, or CDR-SB, by 27 percent compared to a placebo.
“All of these amyloid-lowering drugs carry a risk for increased brain hemorrhage,” said Ronald Petersen of the Mayo Clinic in Rochester, Minnesota. “I think the primary outcomes, the secondary outcomes, the amyloid-lowering is pretty impressive.”
The Alzheimer’s Association said the data confirms the drug “can meaningfully change the course of the disease” and called on US regulators to approve the company’s application for accelerated approval.
The full data showed that some patients with a genetic risk of developing the mind-wasting disease did not benefit from lecanemab based on the CDR-SB measure.
They did, however, show improvement for the trial’s secondary goals, including other measures of cognition and daily function. Overall, lecanemab patients benefited by 23 to 37 percent compared with a placebo on these secondary trial goals.
“I believe it’s an important benefit that will justify full approval. But of course, we want a bigger benefit,” said Paul Aisen, director of the Alzheimer’s Therapeutic Research Institute at the University of Southern California and co-author of the study published in the New England Journal of Medicine.
He said lecanemab is likely to provide greater benefit if given earlier in the disease, “before you’ve accumulated enough irreversible damage to be causing symptoms”.
Detailed data from the study were presented at the Clinical Trials on Alzheimer’s Disease meeting in San Francisco.
Researchers are preparing to test lecanemab with other experimental drugs, and how it works in high-risk people before they show the first signs of memory problems.