Drugs designed to remove amyloid beta proteins from the brain do not produce meaningful improvements in dementia severity and may increase risks of bleeding and swelling, according to a new Cochrane review released on Apr. 16.
The findings are significant because amyloid beta-targeting drugs have been promoted as potential treatments for early-stage Alzheimer's disease, with the hope that removing these proteins could slow or prevent progression. However, the evidence now suggests that such benefits are minimal or absent.
The review analyzed data from 17 clinical trials involving more than 20,000 participants who had mild cognitive impairment or mild dementia due to Alzheimer's disease. Researchers found that while these drugs effectively removed amyloid proteins from the brain, this did not lead to noticeable clinical improvements. "Unfortunately, the evidence suggests that these drugs make no meaningful difference to patients," said lead author Francesco Nonino, neurologist and epidemiologist at the IRCCS Institute of Neurological Sciences of Bologna in Italy.
In addition to their limited effectiveness, anti-amyloid drugs were associated with an increased risk of brain swelling and bleeding seen on scans. Most cases did not present symptoms immediately, but researchers noted inconsistencies in symptom reporting across studies and said long-term effects remain unclear.
Given these results, authors of the review recommend shifting research focus toward other treatment approaches for Alzheimer's disease. Senior author Edo Richard, Professor of Neurology at Radboud University Medical Centre, said: "I see Alzheimer's patients in my clinic every week and I wish I had an effective treatment to offer them. 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. Given the absence of correlation between amyloid removal and clinical benefit, we need to explore other pathways to help address this devastating disease."
