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What Are Anti-amyloid Therapies for Alzheimer’s Disease?

Medically Reviewed by Sabrina Felson, MD on August 08, 2022

The newest treatment approved to fight Alzheimer’s disease is a kind of drug called an anti-amyloid. It’s the first treatment that works directly on what may cause the disease, instead of just the symptoms.

Anti-amyloids target the protein fragments that build up in your brain and form plaques, a defining feature of the disease. The approval of the new drug, aducanumab (Aduhelm), was controversial, and it isn’t widely available.

But scientists think they’re on the right track, and a lot of research is being done to learn how anti-amyloids may help people with Alzheimer’s disease.

What Is an Anti-amyloid?

People with Alzheimer’s disease have too much of a protein called beta-amyloid in their brains. These proteins clump together to form plaques. They build up between nerve cells in your brain called neurons and keep them from communicating with each other. That contributes to memory and thinking problems. Studies show that this protein can also bind to nerve cell receptors, causing a reaction that eats away at the synapses that pass information between neurons.

Anti-amyloid drugs help lower the amount of beta-amyloid in your brain. The hope is that removing plaques will keep brain cells working normally for longer. They’re a kind of immunotherapy, using a monoclonal antibody directed against the culprit protein. A monoclonal antibody is a lab-made antibody. It attaches to targets in the body and destroys them. The first drug of this kind has been approved for the treatment of Alzheimer’s disease.

Aducanumab (Aduhelm). In June of 2021, the FDA gave accelerated approval to aducanumab. That makes it available to people with Alzheimer’s while it’s still being studied.

  • You get this drug through a needle placed in your vein. The process takes about an hour, and you need to do it every 4 weeks. You’ll start at a low dose that’s increased gradually until you reach the amount your doctor has prescribed.
  • A serious potential side effect is called amyloid-related imaging abnormalities (ARIA). This is swelling in your brain that usually goes away on its own. It can also include small spots of bleeding in your brain. You should have regular brain imaging tests, like an MRI, to watch for this. ARIA might cause headache, dizziness, nausea, confusion, and vision problems.
  • Other side effects include an allergic reaction, falls, and diarrhea.

So far, there aren’t any health conditions that mean that you shouldn’t take this drug because of them. No drug interactions have been found either. But that could be because you have to be in good health to take part in the clinical trials. Researchers are concerned that if you take a blood thinner, you may be more likely to have bleeding in your brain.

It does appear to be safe to take other Alzheimer’s medications at the same time as aducanumab.

How Well Do Anti-amyloids Work?

Accelerated approval for aducanumab was controversial. The FDA’s own advisory committee recommended against it. The studies done by the drug company as part of the approval process did show the drug removes amyloid plaques. But they didn’t prove that it makes a difference in people’s symptoms or outcomes.

In one study, some people who got the highest dose of aducanumab had a slower loss of certain cognitive functions, like their ability to think clearly and handle daily activities. But in another study, people who got the drug actually got worse than those who didn’t. As part of the accelerated approval process, the drug company has until 2030 to prove whether it works or it may be taken off the market.

The verdict on other anti-amyloid drugs is also mixed. Several drugs are being tested, but so far they haven’t shown the same success as aducanumab in reducing amyloid plaques. However, a recent review of studies on anti-amyloid drugs found they may have a small benefit in terms of slowing down the progression of your symptoms.

It’s possible that for these drugs to help, you need to take them before Alzheimer’s has done a lot of damage to your brain.

Who Can Take Anti-amyloids?

Researchers tested aducanumab in people with either early-stage Alzheimer’s or the condition that often comes before it, mild cognitive impairment. They don’t know yet whether it would have any benefit for people with more advanced Alzheimer’s.

Your doctor should be sure you have amyloid deposits in your brain before they prescribe an anti-amyloid. You may get tests including a PET scan or a spinal tap.

Access to aducanumab is very limited right now. Some major hospital systems don’t offer it.

It’s expensive, and insurance won’t always cover it. Medicare will only pay for it if you’re enrolled in an approved clinical trial. Some private insurance companies aren’t covering it at all. Others want your doctor to show it’s medically necessary or that you’re taking it as part of a clinical trial.

Only a small number of people with Alzheimer’s disease meet the qualifications for taking part in an aducanumab study. The main clinical trials don’t allow people who take blood thinners other than aspirin. They also don’t allow those with a history of:

  • Heart problems or stroke
  • Bleeding disorders
  • Kidney or liver problems

That leaves out more than 90% of people covered by Medicare who have Alzheimer’s.

What’s the Latest Research on Anti-amyloids?

Studies continue on aducanumab to get a clearer picture of whether it really slows the progression of Alzheimer’s disease and whether it’s more likely to help certain people rather than others.

Researchers are studying several other anti-amyloid drugs in late-stage trials, including:

  • Donanemab
  • Gantenerumab
  • Lecanemab
  • Solanezumab

They’re also looking at these drugs in combination with other treatments designed to change the course of the disease.

Studies on drugs designed to stop the production of beta-amyloid, rather than get rid of it, have not shown promise because of harmful side effects.

If scientists can prove that reducing amyloid plaques slows down thinking and memory problems in Alzheimer’s disease, a vaccine against beta-amyloid may be the next step. Several potential vaccines are in the early stages of development.

Show Sources

SOURCES:

National Institute on Aging: “How Is Alzheimer's Disease Treated?” “What Happens to the Brain in Alzheimer's Disease?”

Alzheimer’s Association: “Medications for Memory, Cognition and Dementia-Related Behaviors,” “Aducanumab Approved for Treatment of Alzheimer’s Disease.”

Health Psychology Research: “Aducanumab, a Novel Anti-Amyloid Monoclonal Antibody, for the Treatment of Alzheimer’s Disease: A Comprehensive Review.”

PLOS Biology: “If amyloid drives Alzheimer disease, why have anti-amyloid therapies not yet slowed cognitive decline?”

StatPearls: “Aducanumab.”

The Journal of Prevention of Alzheimer's Disease: “The Future of AD Clinical Trials with the Advent of Anti-Amyloid Therapies: An CTAD Task Force Report,” “The Future of Anti-Amyloid Trials.”

Alzheimer’s & Dementia: “Cognitive outcomes of anti-amyloid-β monoclonal antibodies in patients with Alzheimer's disease: A systematic review and meta-analysis of randomized controlled trials.”

Neurology Clinical Practice: “Practical Considerations in the Administration of Aducanumab for the Neurologist.”

News release, Biogen.

News release, Centers for Medicare & Medicaid Services.

Mayo Clinic:  “Alzheimer's treatments: What's on the horizon?”

ClinicalTrials.gov: “Interventional Studies: Alzheimer’s Disease.”

Cleveland Clinic: “Monoclonal Antibodies,” “Aducanumab FAQ.”

Cigna: “Aducanumab.”

United Healthcare: “Specialty medical injectable drug program, requirements and drug policy updates: Aduhelm®.”

Excellus: “Prescription Drug Policies: Aducanumab.”

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