USA—An experimental drug that removes a substance called amyloid from the brain appears to slow down Alzheimer’s disease.
The drug, called lecanemab, reduced the rate of cognitive decline by 27% in a study of 1,795 people in the early stages of Alzheimer’s, scientists reported at the Clinical Trials on Alzheimer’s Disease meeting in San Francisco.
The long-awaited trial data, published in the New England Journal of Medicine, comes about two months after drugmakers Biogen and Eisai announced that lecanemab had been found to reduce cognitive and functional decline by 27% in their Phase 3 trial.
The drug, Lecanemab, has been shown to clear the brain of toxic amyloid protein and delay the onset of symptoms during trials, making it the world-first treatment to slow brain decline.
People who got infusions of lecanemab scored about half a point better on a zero-to-18-point scale of mental functioning, a slight but statistically significant difference.
Although it is not a cure, it may help prolong the quality of life of millions of patients currently afflicted by neurodegenerative disease.
About one in five people who got lecanemab in the study experienced an adverse event, such as swelling or bleeding in the brain.
People also reported symptoms including headaches, visual disturbances, and confusion. The treatment has been linked to two deaths.
The two deaths reported in the media occurred during Clarity AD’s ‘open-label extension’, a period after a trial has formally ended, during which participants who were receiving placebo can opt to receive the experimental treatment. Both deaths involved stroke-related complications.
In one case, reported by STAT, a participant who used a prescribed anti-coagulant, or blood thinner, for a heart condition, died after a heart attack and four mini-stroke-like events.
In the other case, reported by Science, the individual died from bleeding in the brain after she was given an anti-clot medicine that is used to treat strokes in an emergency.
According to both news outlets, scientists think it plausible that lecanemab could have weakened the blood vessels in these people’s brains by clearing away amyloid protein that lined the vessels. The anti-stroke medications could then have triggered bleeding.
Because of the involvement of anti-coagulants and other factors, it’s a bit difficult to elucidate whether lecanemab had a role in the deaths, said Marwan Sabbagh, a neurologist at the Barrow Neurological Institute in Phoenix, Arizona, while presenting data at the conference.
“These things are continuing to be explored,” he said. Although the rate of brain hemorrhage is low with lecanemab, it does increase with the use of anti-coagulants, he added.
The data is already being assessed by regulators in the US who will soon decide whether lecanemab can be approved for wider use.
The developers – the pharmaceutical companies Eisai and Biogen – plan to begin the approval process in other countries next year.
The FDA controversially approved Aduhelm, which was also developed by Biogen, last year on the basis of its effects on amyloid, but without clear evidence of cognitive benefit.
Sales of Aduhelm have been slow, largely because Medicare will only cover the drug for patients participating in a clinical trial.