April 16, 2026
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A new meta-analysis concludes that Alzheimer's disease medications that target the buildup of plaques in the brain have no noticeable benefits on memory and cognitive decline.
A new, large-scale review of studies on medications aimed at slowing the progress of early Alzheimer's disease has drawn a sobering conclusion: the drugs don't work.
Alzheimer's affects more than 7 million Americans, with that total projected to nearly double by 2050. It has been linked to the buildup of amyloid proteins in the brain, also called amyloid plaques. Recent research suggests that the collection of these plaques occurs as many as 22 years before the emergence of dementia symptoms, the Alzheimer's Association says.
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Anti-amyloid drugs have been a major focus of research for slowing the progression of Alzheimer's, which has no cure. The medications aim to reduce the build-up of plaques in the brains of people who have been tested for them.
The U.S. Food and Drug Administration has approved two anti-amyloid medications in recent years: Leqembi in 2023 and Kinsula in 2024. Clinical trials conducted by the pharmaceutical companies to gain FDA approval — one trial for each medication — suggested they may reduce cognitive decline in some patients.
"For some individuals with early Alzheimer's disease, these approved treatments mean more time with memory and thinking intact; more time for independence and daily life," Maria Carrillo, chief science officer with the Alzheimer's Association, said in an email. "... Multiple regulatory agencies worldwide have approved treatments in this class based on rigorous clinical trial data showing statistically significant and clinically meaningful slowing of cognitive decline in people with early Alzheimer's."
But the Cochrane Collaboration, the worldwide nonprofit of health researchers that conducted the meta-analysis, found that after 18 months of treatment, the anti-amyloid drugs made "little to no difference on how bad" people's dementia symptoms were.
Additionally, the review found anti-amyloids "probably" had little impact on decline in people's memory and thinking ability. They may have "slight improvement" on complex everyday activities, such as shopping and managing finances, but they probably also caused a small increase in brain swelling and in microbleeds in the brain, the analysis says.
"Unfortunately, the evidence suggests that these drugs make no meaningful difference to patients," lead author Francesco Nonino, a neurologist and epidemiologist at the IRCCS Institute of Neurological Sciences of Bologna, Italy, said in a statement.
Nonino and the other researchers looked at 17 trials involving seven anti-amyloid medications, including the trials for Leqembi and Kinsula. The Cochrane researchers also examined studies for four drugs that had not been shown to be effective and that were not approved, in addition to a medication that was taken off of the market, in part due to safety concerns.
The studies in the Cochrane review involved more than 20,000 patients with mild dementia due to Alzheimer's. The average age of patients in the studies was 70 to 74.
"The results of our meta-analysis show that removing amyloid from the brain does not improve cognition and also does not slow cognitive decline," another Cochrane researcher, Edo Richard, a neurologist at Radboud University Medical Centre in the Netherlands, said in a press conference. "The idea that removing the amyloid will benefit patients was refuted by our results."
But Carrillo of the Alzheimer's Association said that "while, overall, we respect Cochrane's role in evidence review, this analysis inappropriately includes a more broad, less relevant range of studies."
Local researchers also have criticized the Cochrane review.
"The problem with the review is the mix of ingredients," Dr. Jason Karlawish, a director of the Penn Memory Center at the University of Pennsylvania, told the New York Times. "They took some of the rotten ingredients and mixed it in with the fresh food, and the result is a stinky stew."
Dr. David Wolk, director of the Penn Alzheimer's Disease Research Center and division chief of cognitive neurology at the University of Pennsylvania, agreed. He told the AARP that examining them together "is conflating drugs into a single class when clearly, they have different degrees of target engagement. One simply cannot treat all these studies as equal."
"Glaringly missing from this analysis is that behind every data point is a person," Carrillo said. "Many people living with mild cognitive impairment and early Alzheimer's disease who are using these treatments are taking trips they weren't sure they'd take, spending joyful time with friends and family, making plans for next month, doing things they love, and staying present in their lives and the lives of the people they care about. Their lives and their experiences cannot be ignored. Nor should they be cheated out of approved options based on limited evidence."
