An independent review has raised significant doubts about the clinical benefits of new Alzheimer's drugs designed to target amyloid protein buildup in the brain. The findings come after the National Institute for Health and Care Excellence (NICE) in the UK previously declined to recommend two such treatments for use in the National Health Service (NHS), citing concerns over cost-effectiveness and potential side effects.

Alzheimer’s disease, the most common form of dementia, progressively impairs memory and cognitive function. As populations age, the number of people affected by the condition continues to rise, driving urgent calls for effective therapies. Its pathology has been linked in part to the accumulation of amyloid protein plaques, which has guided the development of several antibody-based treatments aiming to clear these deposits.

Despite the theoretical promise of amyloid-targeting drugs, clinical trials have shown that while many can reduce amyloid levels, they do not translate into meaningful improvement in patients' symptoms. Two antibodies permitted for limited use in the UK—donanemab and lecanemab—have demonstrated only modest slowing of cognitive decline during trials. However, NICE concluded these benefits were too marginal to justify their high costs and the risk of adverse effects, including brain swelling and bleeding observed in a substantial proportion of patients.

The recent comprehensive review examined data from multiple large-scale trials involving nine amyloid antibodies. Authors found that these treatments “likely have no clinically meaningful positive effects,” meaning the small cognitive benefits observed were unlikely to be perceptible to patients or their carers in day-to-day life.

Manufacturers of these drugs contested the review’s conclusions. A representative of donanemab's maker criticized the pooling of all amyloid therapies as inappropriate and reaffirmed confidence in their product’s clinical effectiveness. The producer of lecanemab declined to comment.

Meanwhile, experts emphasize that the focus on amyloid-targeting drugs may distract from currently approved treatments that offer symptomatic relief. Two medications, donepezil and memantine, are approved by NICE but reportedly underutilized, with only about half of Alzheimer’s patients receiving them.

In parallel, researchers are exploring alternative pathways contributing to Alzheimer’s, such as the accumulation of tau protein, which may also drive nerve cell death. Several tau-targeting drugs are in development, and ongoing trials are investigating whether combining amyloid and tau therapies may enhance outcomes.

“Probably to really get on top of Alzheimer’s, you need to treat both in conjunction,” said a neurologist involved in dementia research, noting that effective treatment of complex diseases often requires targeting multiple biological mechanisms. A combination approach, potentially including drugs aimed at amyloid, tau, and other factors, reflects strategies employed in managing conditions like HIV, cancer, and heart disease.

As research continues, the debate over the value of amyloid antibodies underscores the challenges in developing disease-modifying treatments for Alzheimer’s and balancing hope for innovation with evidence-based care.