• Posted April 16, 2026

New Alzheimer's Drugs Provide No Meaningful Benefit, Major Evidence Review Concludes

New anti-amyloid drugs approved to treat Alzheimer’s disease have no clinically meaningful positive effects for patients, a major evidence review has concluded.

Drugs like Leqembi (lecanemab) and Kinsula (donanemab) have little to no effect on patients’ cognitive decline and dementia, according to results published by the Cochrane Review.

These drugs target amyloid beta, a protein that forms toxic clumps in the brains of people with Alzheimer’s.

“Unfortunately, the evidence suggests that these drugs make no meaningful difference to patients,” said lead researcher Dr. Francesco Nonino, a neurologist and epidemiologist at the IRCCS Institute of Neurological Sciences of Bologna, Italy.

“There is now a convincing body of evidence converging on the conclusion that there is no clinically meaningful effect,” he said in a news release.

Both the Alzheimer’s Association and the maker of Leqembi, Eisai Inc., took issue with the review because it included data from failed anti-amyloid drugs alongside studies of drugs that achieved U.S. government approval.

“The Cochrane meta-analysis is scientifically deeply flawed by inappropriately combining ineffective antibodies and failed studies with effective, regulatory approved anti-amyloid treatments,” Eisai said in its statement.

“The U.S. Food & Drug Administration (FDA) has stated that lecanemab is part of a newer generation of anti-amyloid therapies targeting aggregated amyloid and has learned from previous failures,” Eisai continued. “Extensive long-term clinical data out to four years and real-world experience with tens of thousands of patients globally show that patients who receive lecanemab continue to benefit from treatment.”

For the review, researchers analyzed data from 17 clinical trials involving more than 20,000 participants, all looking at how anti-amyloid drugs affected people with mild cognitive impairment or mild dementia due to Alzheimer’s.

The trials tested the effectiveness of aducanumab, bapineuzumab, crenezumab, donanemab, gantenerumab, lecanemab, ponezumab, remternetug and and solanezumab, according to the review.

Researchers concluded that the absolute effects of anti-amyloid drugs on cognitive decline and dementia were “absent or trivial,” falling well below the standard for clinical effectiveness.

“While early trials showed results that were statistically significant, it is important to distinguish between this and clinical relevance,” Nonino said. “It is common for trials to find statistically significant results that do not translate into a meaningful clinical difference for patients.”

Anti-amyloid drugs also likely increase the risk of dangerous swelling and bleeding in the brain, the team noted.

The drugs do successfully remove amyloid from the brain, but that doesn’t lead to meaningful cognitive benefits for patients, researchers said.

The team recommended that future Alzheimer’s research focus on other targets than amyloid beta, as future trials targeting the protein are unlikely to provide clear benefit to patients.

“I see Alzheimer’s patients in my clinic every week, and I wish I had an effective treatment to offer them,” senior researcher Edo Richard, a professor of neurology at Radboud University Medical Center in The Netherlands, said in a news release.

“Existing approved drugs offer some benefit for some patients, but there remains a high unmet need for more effective treatments. Sadly, anti-amyloid drugs do not offer this and bring additional risks,” Richard said. “Given the absence of correlation between amyloid removal and clinical benefit, we need to explore other pathways to help address this devastating disease.”

Maria Carrillo, chief science officer and medical affairs lead for the Alzheimer’s Association, said that the association maintains continued “confidence in the use of these treatments across a wide variety of care settings.”

“In real-world clinical settings, including mild cognitive impairment and early Alzheimer’s patients, the Association’s ALZ-NET has found that the amyloid targeting monoclonal antibodies have efficacy and safety very similar to what was reported in the Phase 3 clinical trials — clinically meaningful slowing of disease progression/cognitive decline with modest side effects,” she said.

Carrillo noted that multiple regulatory agencies around the world have approved treatments in this class based on "rigorous" clinical trial data showing significant and "clinically meaningful" slowing of decline in early Alzheimer’s patients.

“While, overall, we respect Cochrane’s role in evidence review, this analysis inappropriately includes a more broad, less relevant range of studies,” Carrillo said. 

“Glaringly missing from this analysis is that behind every data point is a person,” she added. 

“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," Carrillo said. "Their lives and their experiences cannot be ignored. Nor should they be cheated out of approved options based on limited evidence.”

More information

Northwell Health has more on anti-amyloid treatments for Alzheimer’s disease.

SOURCES: Cochrane, news release, April 15, 2026; Eisai, statement, April 15, 2026; Maria Carrillo, chief science officer and medical affairs lead, Alzheimer’s Association