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

Medically Reviewed by Christopher Melinosky, MD on February 08, 2023
4 min read

The newest treatment approved to fight Alzheimer’s disease is a kind of drug called an anti-amyloid. They work 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. There are now two available; aducanumab-avwa (Aduhelm) and lecanemab-irmb (Leqembi). They are not without controversy because they may also lead to swelling of the brain and neither is 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.

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) andlecanemab-irmb (Leqembi). The FDA gave accelerated approval to aducanumab in In June of 2021,, while lecanemab-imb received approval in January 2023. 

  • You get these drugs through a needle placed in your vein. The process takes about an hour. Aduhelm is taken monthly while Leqembi is every two 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.

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. 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.

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.

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.