Are anti-amyloid treatments right for us?

Two medicines can now slow early Alzheimer's disease a little: lecanemab (Leqembi) and donanemab (Kisunla). Both remove amyloid (a sticky protein that builds up between brain cells). Many families hear about them and ask, "Can we get this? Should we?"

Only some people qualify. For those who do, the choice is personal. The benefit is modest, the risks are real, and treatment takes a lot of time. This page helps you decide together with the doctor.

What these treatments are

Lecanemab and donanemab are monoclonal antibodies (lab-made proteins that stick to one target). They help the body clear amyloid from the brain.^1,2 Unlike older medicines such as donepezil, which ease symptoms for a time, they aim to slow the disease itself, not to improve memory.³ For full details, see lecanemab (Leqembi) and donanemab (Kisunla).

Who may qualify

A person may be a candidate if all of these are true:^1,2,3,4

• The stage is early. The person has mild cognitive impairment (MCI) or mild dementia. Memory and thinking have changed, but the person still does most daily tasks. Doctors often check this with memory tests.
• The cause is Alzheimer's. Other causes, such as Lewy body dementia or mostly blood vessel disease, do not count.⁴
• Amyloid is confirmed. A test must show amyloid in the brain. This is usually an amyloid PET scan or a spinal fluid test.
• A recent brain MRI is safe enough. The MRI must not show too many signs of past bleeding or other problems (see the next section).
• The person can keep up with treatment: regular infusions or shots, several MRI scans, and quick reporting of new symptoms.

These drugs have not been tested in people with moderate or severe dementia. They have also not been tested in people with no symptoms. Their safety and benefit in those groups are unknown.⁵

About blood tests. In May 2025, the FDA cleared the first blood test that helps show whether amyloid is likely present, for adults 55 and older with memory symptoms seen in a specialty clinic. It is not meant to be used alone before treatment decisions.⁶ See blood tests for Alzheimer's.

About age. The lecanemab trial included people aged 50 to 90, and about 4 in 10 were 75 or older. The FDA found no overall differences in safety or benefit for people 65 and older.^1,3

Who should not get them, or needs extra caution

The FDA says a person should not get either drug if they have had a serious allergic reaction to it.^1,2 Expert groups also advise doctors to avoid these drugs, or use great care, in the situations below.^3,4

Never stop a blood thinner or any other medicine to become eligible. It may be protecting against a stroke or clot. Talk with your doctor or pharmacist before changing anything.

Two copies of the APOE e4 gene. About 15% of people with Alzheimer's carry two copies of e4, one from each parent.¹ Their risk of ARIA is much higher. In the lecanemab trial, about 45% of people with two copies had ARIA, compared with 22% of those on placebo.¹ In this small group, the trial did not show a benefit on its main rating scale, though some other measures leaned in favor of the drug.¹ The FDA advises an APOE test before treatment, after a talk about what the result could mean.^1,2 People with two copies can still be treated, but this calls for an extra careful talk. See genes and dementia.

How much do these drugs help?

This is the most important question, and the answer is "a little."

Sources for the table: FDA labels for Leqembi and Kisunla.^1,2

What this means in daily life. Picture two groups who both slowly lose memory and daily skills over 18 months. The group on the drug loses ground about one quarter more slowly. The CDR-SB scale covers memory, judgment, home life, hobbies and personal care. A half-point gap on an 18-point scale is small, and many families may not notice it day to day.

The Alzheimer's Association points out that the drugs slowed decline in memory, knowing time and place, handling money and doing chores.⁵ Some families value any extra time in the mild stage. That is when a person can still take part in plans and decisions.

Experts do not agree on how much this matters. In April 2026, a Cochrane review looked at 17 trials of anti-amyloid drugs with more than 20,000 people. It concluded that the effects on thinking and dementia severity at 18 months were trivial, and that brain swelling was much more common (about 119 per 1,000 people versus 12 per 1,000 on placebo).⁷ Many experts objected. They noted that 15 of the 17 trials tested drugs that failed or were stopped, and some trials did not confirm amyloid first.⁸ They argued this mixes weaker older drugs with the two approved ones.⁸

Either way, these drugs are not a cure. They aim to slow decline, not to bring back lost memory.³ The trials were also fairly short, so benefit over many years is still unclear.⁷

The risks and the work involved

ARIA (amyloid-related imaging abnormalities) means swelling or tiny bleeds in the brain. It is usually found only on MRI, with no symptoms. In the lecanemab trial, about 3 in 100 people had symptoms from ARIA, and brain bleeds larger than 1 cm happened in under 1 in 100. Some people died.¹ Both drugs carry the FDA's strongest warning, a boxed warning.^1,2 See ARIA.

Infusion reactions such as fever, chills, aches or nausea affected about 1 in 4 people in the lecanemab trial. Most were mild.¹

Time. Treatment takes many visits:^1,2

• Lecanemab IV: every two weeks at first. Later it may move to every four weeks. Or a weekly shot at home with a pen.
• Donanemab IV: every four weeks. The doctor may consider stopping once a PET scan shows amyloid has dropped to very low levels.
• Several MRI scans, mostly in the first six months, plus extra scans if symptoms appear.

Cost. Medicare Part B may cover these drugs if the doctor confirms early Alzheimer's with amyloid and enters data in an approved study or registry. After the deductible, you usually pay 20% of the approved amount. Scans and tests add more.⁹ See paying for new Alzheimer's drugs.

A step-by-step guide to deciding

Experts advise that the choice be shared between the doctor, the person and the care partner, based on the person's own values and goals.^3,4 Rating scales are hard to picture, so they suggest talking in terms of goals like staying independent longer.³ You can use the steps below as a simple decision aid. Write your answers in a memory notebook and bring it to the visit.

1. Check the medical basics. Ask the doctor: Is this Alzheimer's? Is it still mild? Has amyloid been confirmed? If not, which test comes next?
2. Check the safety basics. Review the latest MRI, all medicines (especially blood thinners), and any history of seizures, strokes or bleeding.
3. Decide about APOE testing. Talk first about what the result could mean for risk, and for children and siblings who may share the gene.^1,3
4. Picture the benefit. Ask the doctor to explain in plain terms what slowing by about one quarter could mean for this person.
5. Picture the burden. Count the trips, scans and time off work. Ask who will drive and watch for symptoms.
6. Name what matters most. More time in the mild stage? Avoiding risk? Fewer medical visits? Each answer can point a different way.
7. Include the person. In the early stage, most people can take part in this decision. Their wishes should guide it.
8. Decide, then review. You can try treatment and stop later, or say no now and ask again while the person is still in the mild stage.

The trials included few people from some racial and ethnic groups, or with unusual forms of Alzheimer's.³ Ask how well the results apply to you.

Questions to ask the doctor

Do we qualify?

• What stage is this: mild cognitive impairment or mild dementia?
• How will we confirm amyloid? Does anything in my MRI, medicines or health history rule me out?

What could we expect, and what are the risks?

• What benefit could we hope for, and how might it change daily life?⁵
• How common are side effects, how will you watch for them, and might I have to stop?⁵
• Should I have an APOE test? Who do we call at night or on weekends?

What will it take and cost?

• How often are the infusions or shots, and where? When would we stop?
• Is your clinic in a Medicare-approved registry? What will we pay for the drug, scans and visits?

If treatment is not right for you

Not qualifying, or deciding against these drugs, is not giving up. Good care still makes a big difference:

• Older memory medicines like donepezil may help symptoms for a time.
• Clinical trials test new drugs for people at many stages. See also new treatments being tested.
• Planning ahead while the person can take part, such as an advance directive, protects their wishes.
• Support for the care partner matters too. See caregiver burnout and the first 30 days after a diagnosis.

The Alzheimer's Association 24/7 Helpline at 800-272-3900 can answer questions about these treatments any time.⁵ The Association also suggests talking with a doctor who has experience with these drugs.⁵ A diagnosis can bring deep grief. If you or the person you care for has thoughts of suicide, call or text 988 any time.

Education only. This page is general information written from the sources listed. It is not medical, legal or financial advice and does not replace a doctor, therapist or lawyer who knows your situation. How we write and check pages.