Alzheimer's disease slowly affects your memory, thinking, and ability to manage daily life. One of the key changes it causes is a buildup of amyloid beta, a protein that can form sticky clumps in your brain called plaques.

Amyloid-targeting therapies are medicines that help remove some of that amyloid. You may hear them called anti-amyloid therapy or anti-amyloid monoclonal antibodies.

These treatments don't cure Alzheimer's disease or reverse damage that's already happened. But for some people in the early stages, they may help slow declines in memory, thinking, and daily function.

What Are Amyloid-Targeting Therapies?

Your body makes antibodies to tag things it wants to get rid of, like germs or other harmful substances. Amyloid-targeting therapies are lab-made antibodies. They're called "monoclonal" because they're made to find and stick to one specific thing. In this case, the target is amyloid.

Amyloid-targeting therapies are considered a type of disease-modifying treatment. That means they might help change the course of Alzheimer's, but they can’t cure it.

How Do Amyloid-Targeting Therapies Work?

Different amyloid-targeting drugs may attach to different forms of amyloid. But the basic idea is the same: Once the antibody sticks to amyloid, it signals your body's cleanup system to help remove some of it from your brain.

Amyloid doesn't always look the same. It can be:

  • Small, free-floating pieces
  • Partly clumped together
  • Collected into larger clumps (plaques)

With amyloid-targeting therapies, the goal is to remove amyloid while your disease is still early enough to help slow decline.

Which Amyloid-Targeting Therapies Are Used to Treat Alzheimer’s?

The two amyloid-targeting therapies currently available for Alzheimer's are:

In 2021, the FDA approved an amyloid-targeting drug called aducanumab (Aduhelm). But the drugmaker later stopped making it, and it's no longer on the market.

When Are Amyloid-Targeting Therapies Considered for Alzheimer’s?

Your doctor may talk with you about lecanemab or donanemab if you have early symptomatic Alzheimer's. This includes mild cognitive impairment (MCI) due to AD or mild Alzheimer's dementia.

You also need tests that show amyloid buildup in your brain. Many things can cause memory problems. If you don't have excess amyloid, these drugs are unlikely to help, and you could still have side effects.

Here are more details:

Mild cognitive impairment (MCI) due to AD. You have memory or thinking changes that are more than normal aging. You can usually still manage most daily tasks on your own, like keeping track of your schedule, paying bills, or driving.

Mild Alzheimer's dementia. Your memory or thinking problems are stronger and more noticeable to you or your loved ones. Symptoms start to get in the way of everyday life. You may need help with things like handling money, medications, appointments, or transportation.

Confirmed amyloid buildup. Your doctor will check for amyloid plaques in your brain, often with an amyloid PET scan or a spinal fluid test (called a lumbar puncture).

What else will your doctor check?

Before prescribing an amyloid-targeting therapy, your doctor will look at your full health picture. This helps them confirm that the medicine is likely to help and understand your personal risk of side effects.

This may include:

  • Your medical history
  • Your current medications
  • A talk with a care partner about changes to your memory, thinking, or daily function
  • Cognitive tests to see how your memory and thinking compare with those of others your age
  • Brain MRI to look for bleeding risk or other brain changes
  • Blood tests to rule out other causes of memory problems
  • APOE genetic testing to help gauge your risk of ARIA and other side effects

These drugs aren't used just because Alzheimer's runs in your family. But your doctor can refer you to a neurologist or memory specialist who'll help you watch for early symptoms.

How Do You Take Amyloid-Targeting Therapies?

You usually get them through a vein (IV infusion) in a medical setting.

You'll also need MRIs of your brain before and during treatment. These scans help your team look for side effects like brain swelling or small bleeds. Your MRI schedule will depend on which drug you're on and how closely your doctor wants to monitor you.

Lecanemab

You usually start with an IV infusion every two weeks. Each visit takes about an hour or so. After 18 months, your doctor may talk with you about:

  • Staying on the same two-week IV schedule
  • Switching to an IV infusion every four weeks
  • Changing to a weekly under-the-skin shot (Leqembi Iqlik)

Donanemab

You get this medicine through a vein every four weeks (once a month). The infusion itself often lasts around 30 minutes. But the total time you're in the clinic may be longer.

Your doctor may adjust the dose over your first few treatments.

What happens if you miss a dose of lecanemab or donanemab?

You can usually delay treatment by a few days without much of a problem. But if you need to miss treatment, tell your doctor. They'll help you adjust your schedule safely.

How Effective Are Amyloid-Targeting Therapies for Alzheimer’s?

In studies, people who took amyloid-targeting therapies still continued to lose some memory, thinking skills, and independence over time. But on average, they declined about 30% more slowly than people who didn't get the study drug.

That 30% is a meaningful number to researchers, but it may not feel like a big change day to day. One way to think about it is that you may get several extra months before your memory, thinking, or independence changes as much as it might have without treatment.

For some people, the hope of any extra time may feel very important. For others, the side effects, costs, travel to an infusion center, and frequent follow-up visits may not feel worth a modest benefit.

Are Amyloid-Targeting Therapies Safe?

They can be safe for the right person. But these aren't low-risk drugs. That's why your doctor will look closely at your health history and MRIs before starting treatment.

The biggest safety concern is amyloid-related imaging abnormalities, or ARIA. You'll get regular MRIs to look for ARIA. It usually doesn't lead to big problems, especially when caught early. But it can be life-threatening in rare cases.

ARIA usually doesn't cause symptoms, but get medical help right away if you have:

  • A new or worsening headache
  • Confusion or dizziness
  • Vision changes
  • Nausea
  • Trouble walking or talking
  • Weakness or numbness
  • Seizure

Your chances of getting ARIA may be different from someone else's. The risk depends on things like:

  • Your APOE gene status
  • Signs of old brain bleeds on an MRI
  • Signs of blood vessel disease in the brain
  • Whether you take blood thinners
  • Your overall stroke or bleeding risk

People with the APOE4 gene have a higher chance of ARIA. This doesn't always mean you can't get amyloid-targeting therapy. But it means your doctor should talk with you about the possible risks of treatment.

What Are Side Effects of Amyloid-Targeting Therapies?

Donanemab and lecanemab have many of the same safety concerns because they work in a similar way. Some side effects may be mild and go away on their own. Others can be serious and need medical care.

infographic on alzheimers treatment side effects

It’s rare, but you could have a serious allergic reaction to the medicine. Tell your doctor if you have:

  • Swelling of your face, lips, tongue, or throat
  • Chest tightness
  • Coughing, wheezing, or trouble breathing
  • Hives
  • Lightheadedness

Get emergency help right away if you have trouble breathing, throat swelling, severe dizziness, or feel like you might pass out.

Tell every doctor who treats you that you're taking an amyloid-targeting therapy, especially in a medical emergency. ARIA symptoms can look like those of a stroke. Some stroke treatments may raise the chance of bleeding.

Who Shouldn’t Take Amyloid-Targeting Therapies?

There are strict guidelines for who can take amyloid-targeting therapies. Your doctor may not want you to take these drugs if you have:

  • A serious allergy to the medicine or any of its ingredients
  • Memory or thinking problems not caused by Alzheimer's disease
  • Moderate or advanced dementia
  • MRI scans that suggest a higher chance of brain bleeding
  • A need for blood-thinning medicine (anticoagulants)
  • A recent stroke, seizure, or serious brain event
  • Ongoing treatment with immune-suppressing drugs
  • A serious health issue, such as heart, liver, kidney, or lung disease
  • A history of certain cancers within the last five years
  • Two copies of the APOE4 gene
  • A medical situation that makes repeated MRI scans unsafe or not possible

Some treatment centers may have more rules. Your doctor can let you know which criteria they use and why.

Not qualifying for these drugs can be upsetting. But it usually means your care team thinks the risks are too high, the benefits are too low, or the treatment doesn't match your stage of disease.

How Much Do Amyloid-Targeting Therapies Cost?

Amyloid-targeting therapies are expensive. The list price for a year of treatment is about:

  • $26,500 for lecanemab (Leqembi)
  • $32,000 for donanemab (Kisunla)

Drugmakers usually don't expect you to pay the list price. Your actual cost depends on things like your:

  • Health insurance
  • Deductible and copays
  • Infusion center fees
  • Costs of extra visits or scans

Before you start treatment, call your insurance company and ask for your out-of-pocket cost. Your doctor's office or treatment center may also be able to provide a cost estimate.

If you have Medicare, these drugs may be covered under Medicare Part B if you meet certain rules. Your doctor must confirm that you have amyloid plaques and that you have mild cognitive impairment due to Alzheimer's disease or mild Alzheimer's dementia.

After you meet your Part B deductible, you typically pay 20% of the Medicare-approved amount for the drug. Because the total price is high, what's left to pay can still add up to thousands of dollars a year if you don't have supplemental coverage.

These resources may help lower your costs:

Your hospital's social worker, the Alzheimer's Association, or a Medicare counselor with your State Health Insurance Assistance Program (SHIP) may also help you find ways to pay for treatment.

Clinical Trials for Amyloid-Targeting Therapies

The approvals for lecanemab and donanemab were based on large clinical trials in people with early symptomatic Alzheimer's disease and confirmed amyloid plaques. Research in this area is still ongoing.

Current studies are looking at questions such as:

  • Can amyloid-targeting treatment help even earlier in the disease?
  • Can newer anti-amyloid antibodies help but with fewer side effects?
  • What pros and cons happen if you're on these treatments for years?

Ask the doctor who treats your Alzheimer's disease if there are clinical trials near you, and what the risks and time commitment would be if you join one. You can also find studies through the Alzheimer's Association's TrialMatch platform or search on  ClinicalTrials.gov.

What to Know if You're a Caregiver

If you care for someone with Alzheimer's who takes an amyloid-targeting therapy, you may play a big role in treatment. It's a good idea to talk openly with the medical team about what's doable for you and how you can get extra support.

You may need to be the one who helps with:

  • Scheduling infusions and keeping a shared calendar
  • Driving to and from treatment and staying at the infusion center
  • Keeping track of MRI appointments and results
  • Letting the care team know about symptom changes and side effects
  • Managing insurance calls or paying medical bills
  • Knowing what to do in an emergency
  • Making sure other doctors (like primary care or ER) know about the drug
  • Giving at-home shots

If your loved one spends part of the year in another state (for example, "snowbirding" in Florida), treatment can be more complicated. You may need to work with a memory specialist to:

  • Find a doctor in that state to take over prescribing
  • Locate an infusion center there
  • Be sure insurance approval is in place in both locations

These tools may also help you find doctors or places to get infusions:

You can also call Lilly Support Services (Kisunla) at 800-545-5979 or Eisai Patient Support (Leqembi) at 833-453-7362.

Are Amyloid-Targeting Therapies Right for Your Alzheimer's Treatment?

Whether you try a drug like lecanemab or donanemab is a shared decision among you, your family, and your doctor.

These medicines may be worth considering if:

  • You have early symptoms of Alzheimer's disease, and
  • Confirmed amyloid plaques in your brain
  • Your doctor feels that the pros outweigh the cons.

They may not be the right fit if:

  • The expected benefit is too small for you.
  • Your risk of side effects is high.
  • The cost would be too much of a financial strain.
  • The treatment schedule and monitoring are too hard.

It's OK to take time, ask questions, and weigh what matters most to you. These groups can offer trusted information and support as you think about your choices:

Show Sources

SOURCES:

Carolyn Fredericks, MD, assistant professor of neurology, Yale School of Medicine.

DailyMed (National Library of Medicine): "Kisunla," "Leqembi."

Alzheimer's Association: "Amyloid-Targeting Treatments for Alzheimer's," "Aducanumab Discontinued as an Alzheimer's Treatment."

Cochrane Database of Systematic Reviews: "Amyloid-beta-targeting monoclonal antibodies for people with mild cognitive impairment or mild dementia due to Alzheimer's disease."

Sage Open Aging: "An Update on the Treatment Landscape for Alzheimer's Disease: From Symptomatic Treatments to the Emergence of Amyloid-Targeting Therapies."

Alzheimer's & Dementia: "'Real-world' eligibility for anti-amyloid treatment in a tertiary memory clinic setting," "Amyloid-related imaging abnormalities (ARIA) in anti-amyloid therapies for Alzheimer's disease: An update from the Alzheimer's Association ARIA workgroup," "Benefits and risks of FDA-approved amyloid-targeting antibodies for treatment of early Alzheimer's disease: Navigating clinician-patient engagement."

Ageing Research Reviews: "Serious side effects of Alzheimer's immunotherapy demand scrutiny."

The Journal of Prevention of Alzheimer's Disease: "Donanemab: Appropriate use recommendations."

eNeuro: "Lecanemab and Donanemab as Therapies for Alzheimer's Disease: An Illustrated Perspective on the Data."

Eisai: "Eisai's approach to U.S. pricing for Leqembi (lecanemab), a treatment for early Alzheimer's disease, sets forth our concept of 'societal value of medicine' in relation to 'price of medicine.'"

Lilly: "Lilly's Kisunla (donanemab-azbt) Approved by the FDA for the Treatment of Early Symptomatic Alzheimer's Disease," "Find a memory care specialist."