Experimental Alzheimer's drug renews hope, relatively slows down worsening of disease

An experimental Alzheimer's drug modestly slowed the brain disease's inevitable worsening, researchers reported Tuesday -- and the next question is how much difference that might make in people's lives.

Japanese drugmaker Eisai and its U.S. partner Biogen had announced earlier this fall that the drug lecanemab appeared to work, a badly needed success after repeated disappointments in the quest for better Alzheimer's treatments.

Now researchers are getting their first peek at the full results of the study of nearly 1,800 people in the earliest stages of the mind-robbing disease. The data was presented at an Alzheimer's meeting in San Francisco and published in the New England Journal of Medicine.

Every two weeks for 18 months, study participants received intravenous lecanemab or a dummy infusion. Researchers tracked them using an 18-point scale that measures cognitive and functional ability.

Those given lecanemab declined more slowly -- a difference of not quite half a point on that scale, concluded the research team led by Dr. Christopher van Dyck at Yale University.

That's a hard-to-understand change but measured a different way, lecanemab delayed patients' worsening by about five months over the course of the study, Eisai's Dr. Michael Irizarry tells The Associated Press.

"In this clinical trial for the lecanemab subject to go from point A to point B in 18 months, individuals on placebo will go from that same point A to point B in 12.7 months," Eisai's Ivan Cheung says.

Also, lecanemab recipients were 31% less likely to advance to the next stage of the disease during the study.

But doctors are divided over how much difference those changes may make for patients and families.

The trial is important because it shows a drug that attacks a sticky protein called amyloid -- considered a chief culprit behind Alzheimer's -- can delay disease progression, said Maria Carrillo, chief science officer for the Alzheimer's Association.

"We all understand that this is not a cure, and we're all trying to really grasp what it means to slow Alzheimer's," says Carrillo.

Amyloid-targeting drugs can cause side effects that include swelling and bleeding in the brain, and lecanemab did as well in about 13% of recipients. Eisai said most were mild or asymptomatic.

Also, two deaths have been publicly reported among lecanemab users who also were taking blood-thinning medications for other health problems. Eisai said Tuesday the deaths can't be attributed to the Alzheimer's drug.

The Food and Drug Administration is considering accelerated approval of lecanemab, with a decision expected in early January. If approved, it would be the second anti-amyloid drug on the market.

Nearly all Alzheimer's treatments available for millions worldwide only temporarily ease symptoms.