Effectiveness and Safety of Anti-Amyloid Monoclonal Antibodies for Alzheimer’s Disease and MCI

Anti-amyloid monoclonal antibodies likely provide little to no benefit in slowing memory decline or dementia severity for people with mild cognitive impairment (MCI) or mild Alzheimer’s disease, according to a review of 17 studies involving 20,342 people. The findings, current as of August 7, 2025, indicate these treatments probably cause more brain swelling and microbleeds than placebo treatments.

The review found that after 18 months of treatment, these laboratory-produced medicines probably make little to no difference in the decline of memory functioning, thinking ability, or the ability to manage everyday activities. The data suggests that successfully removing amyloid proteins from the brain is not associated with clinically meaningful improvements for patients.

Do anti-amyloid monoclonal antibodies slow Alzheimer’s decline?

Evidence from 13 studies involving 9,895 people suggests these antibodies probably do not slow the decline in memory and thinking. Similarly, data from nine studies of 8,053 people indicates they may make little to no difference in the severity of dementia symptoms.

One study of 1,252 people noted a possible small improvement in complex tasks, such as managing finances, shopping, taking medication, and using transportation. However, the overall conclusion is that future research on disease-modifying treatments should likely focus on other options.

What are the risks of brain swelling and microbleeds?

The review found a probable increase in brain swelling among those using monoclonal antibodies. According to 11 studies involving 13,595 people, 119 out of every 1,000 people using the antibodies developed brain swelling, compared to 12 out of 1,000 people receiving a placebo.

Three studies involving 4,308 people also indicated a possible small increase in microbleeds in the brain. The review noted that these medicines do not increase deaths from any cause or other serious unwanted effects as defined by study authors.

Why does the evidence for these treatments have limitations?

Researchers identified two primary limitations in the current evidence. First, most studies did not distinguish between patients who showed symptoms of brain swelling and microbleeds and those where the effects were only visible via scan. This gap may leave patients without a full understanding of the seriousness of the unwanted effects.

Second, the studies were relatively short in duration. This limits the available data on long-term benefits and side effects for those living with Alzheimer’s disease. All 17 studies reviewed were funded by the companies that produced the anti-amyloid monoclonal antibodies.

What happens next for Alzheimer’s research?

Because amyloid removal does not seem to yield meaningful clinical improvements, researchers may shift their focus toward other types of disease-modifying treatments. The current conclusions could change as results from six ongoing studies become available.

Frequently Asked Questions

What are anti-amyloid monoclonal antibodies?
They are laboratory-produced antibodies designed to target and remove amyloid proteins that cause plaques in the brain, which is a characteristic of Alzheimer’s disease.

Do these medicines increase the risk of death?
According to seven studies involving 9,733 people, these antibodies do not increase deaths from any cause compared to a placebo.

What is the difference between MCI and mild dementia?
Mild cognitive impairment (MCI) involves mild memory and thinking problems that do not interfere with everyday life. Mild dementia occurs when these difficulties become serious enough to interfere with daily activities.

How do you feel about the focus of future Alzheimer’s research?