Donanemab (Kisunla)

Donanemab (brand name Kisunla) is a medicine for the early stage of Alzheimer's disease. It clears amyloid (a sticky protein that builds up between brain cells) from the brain. In a large study, it slowed the loss of thinking and daily skills by a modest amount over about 18 months.^1,2

Donanemab is not a cure. People in the study still got worse over time, just more slowly on average.¹ It also has real risks. This page explains what it does, how treatment works, and what to ask the doctor.

What donanemab does

Donanemab is a monoclonal antibody (a lab-made protein that sticks to one specific target). It attaches to amyloid plaques that are already in the brain and helps the body clear them away.² Over 76 weeks in the main trial, amyloid levels dropped sharply in people on donanemab and barely changed in people on placebo.²

Removing amyloid seems to slow the disease a little, but it does not stop it or bring back lost memory. Older memory medicines like donepezil work differently. They ease symptoms for a while, and some people take both.

The FDA approved donanemab on July 2, 2024.³ It received full (traditional) approval, not the quicker accelerated approval.⁶ For an overview of all dementia drugs, see dementia medicines.

What the TRAILBLAZER-ALZ 2 trial showed

The main study included 1,736 people with early Alzheimer's. Their ages ranged from 59 to 86, and the average age was 73. About half got donanemab and half got a placebo (a look-alike with no medicine) for up to 72 weeks.^1,2

The researchers also measured tau (a second protein that forms tangles inside brain cells) with a special PET scan. They looked closely at people with low or medium tau, meaning the disease was less advanced.¹

Doctors tracked change on a rating scale called the CDR-SB. It runs from 0 to 18. It covers memory, knowing time and place, judgment, community activities, home life and hobbies, and personal care. A higher score means more problems.¹

Source for the table: TRAILBLAZER-ALZ 2 results in JAMA.¹

What this means in daily life. People on donanemab still declined, but more slowly. Tests of thinking and of daily tasks, such as handling money or chores, also favored donanemab.³ According to the National Institute on Aging, after one year about 47 in 100 people on donanemab showed no worsening on a key measure, compared with 29 in 100 on placebo.⁴

People whose disease was less advanced at the start tended to benefit more.¹ Still, a difference of under one point on an 18-point scale is small, and many families may not notice it from day to day.

Who was in the trial. About 9 in 10 participants were White. Only a small number were Black, Hispanic or Asian, so we know less about how the drug works in those groups.³

Who can get donanemab

Donanemab is approved to start only in people who:^2,6

• Have mild cognitive impairment (MCI) or mild dementia caused by Alzheimer's disease. See mild cognitive impairment and early-stage dementia.
• Have amyloid confirmed, usually by an amyloid PET scan or a spinal fluid test. See brain scans and spinal fluid tests.

It has not been tested in people with moderate or severe dementia, or in people without symptoms.⁶ A tau PET scan is not required to start.⁵

In May 2025, the FDA cleared the first blood test that helps show whether amyloid plaques are likely present. It is for adults 55 and older with memory symptoms seen in specialty clinics. It is not meant to be used alone.⁹ Read more about blood tests for Alzheimer's.

Who may not be a good fit. Expert guidance published in 2025 advises against donanemab for people whose MRI shows more than four tiny old bleeds, a thin layer of old blood on the brain's surface (superficial siderosis), or major blood vessel damage that is a big part of the memory problem.⁵ The FDA label also urges caution for people who take blood thinners.² Our page Are anti-amyloid treatments right for us? walks through this decision step by step.

Monthly infusions: what to expect

Donanemab is given as an IV infusion (through a needle in a vein) at an infusion center or hospital. Each infusion takes about 30 minutes, once every four weeks.^2,6

There is no at-home shot of donanemab as of October 2026. It is given only by IV.² This is different from lecanemab (Leqembi), which is given every two weeks by IV or can be taken as a weekly shot at home.¹¹ The two drugs have not been compared head to head, so no one can say which works better.

Infusion reactions. Some people get chills, flushing, redness, nausea, sweating, headache, chest pain, trouble breathing, or high or low blood pressure during or soon after an infusion. Most of these happen in the first four infusions.² Serious allergic reactions, including anaphylaxis (a sudden, severe allergic reaction), can happen. The staff will stop the infusion at the first sign of one.²

The revised starting schedule (July 2025)

In July 2025, the FDA approved a change to how donanemab is started.² The first few infusions now use a smaller starting dose and step up more gradually. After the first three infusions, the dose is the same as before. The label now recommends this slower schedule.²

The change came from a study that tested several ways of starting the drug. About 200 people got the original schedule and about 200 got the new, slower one. Here is what it found after one year:²

Source for the table: FDA label for Kisunla.²

Amyloid still dropped by a similar amount with the slower start.² One trade-off: in that study, infusion reactions were reported in 16% of people on the slower schedule.² Your doctor handles the exact doses. Do not try to change the schedule yourself.

Stopping when the plaques clear

This is the biggest difference between donanemab and other anti-amyloid drugs. In the trial, people stopped getting the drug once a PET scan showed their amyloid had dropped to a very low level.^2,6

Many people reached that point fairly quickly:²

• About 1 in 6 people (17%) by 24 weeks
• About 1 in 2 people (47%) by 52 weeks
• About 7 in 10 people (69%) by 76 weeks

The FDA label says doctors can consider stopping when amyloid PET shows plaques are down to minimal levels.² Expert guidance suggests checking with a PET scan, usually 12 to 18 months after starting, and deciding together with the person and family.⁵

Stopping can mean fewer trips and lower cost. But no one yet knows how long the benefit lasts after stopping. The label also does not say when, or whether, treatment should restart if amyloid builds back up.² Ask your doctor how you will be followed after the last infusion.

MRI monitoring

MRI scans are how doctors catch ARIA early, often before any symptoms. The FDA label calls for:²

1. An MRI before the first infusion
2. MRIs before the 2nd, 3rd, 4th and 7th infusions
3. An extra MRI any time symptoms suggest ARIA

Expert guidance adds an MRI before the 12th infusion for people at higher risk of ARIA.⁵ ARIA shows up most often in the first 24 weeks, so the early scans matter most.² Try not to skip one.

ARIA: brain swelling and bleeding

ARIA stands for amyloid-related imaging abnormalities. It comes in two kinds:²

• ARIA-E: swelling or fluid in part of the brain. In the main trial, it cleared on MRI within about 5 months for 4 in 5 people.
• ARIA-H: tiny spots of bleeding, or a thin layer of old blood on the brain's surface.

Most ARIA causes no symptoms and is found only on an MRI. In the main trial, about 6 in 100 people on donanemab had swelling with symptoms.² Rarely, ARIA is serious or deadly. Brain bleeds larger than about 1 cm (under half an inch) have happened, and some people died.² Three deaths in the main trial were judged to be linked to the treatment.^1,4 Donanemab carries the FDA's strongest warning, a boxed warning.²

If ARIA shows up, the doctor may continue, pause until it clears, or stop for good. The choice depends on how it looks on the MRI and whether there are symptoms.²

For more detail, see our full page on ARIA.

APOE testing: why the gene matters

APOE is a gene everyone has. One form, called e4, raises the risk of Alzheimer's. It also raises the risk of ARIA.² People get one copy from each parent, so a person can have zero, one or two copies of e4.

Source for the table: FDA label for Kisunla, main trial using the original starting schedule.²

The FDA recommends an APOE test before starting donanemab.² The doctor should explain what the result could mean before you are tested. A person can still be treated without the test, but no one will know their true risk.² Gene results can matter to children and siblings too. Read more on genes and dementia.

Cost and Medicare coverage

Prices and rules change often. These facts are current as of October 2026.

The drug price. The maker's list price is about $32,000 a year for the drug alone.⁶ Because treatment can stop when plaques clear, the total cost depends on how long a person is treated.⁶ PET and MRI scans, tests and doctor visits add more.⁷

Medicare Part B may cover donanemab for early Alzheimer's with confirmed amyloid. After the Part B deductible, you usually pay 20% of the Medicare-approved amount.⁷ At list price, that could be several thousand dollars a year.

The registry rule. Medicare covers these drugs only if your doctor sends data about your care to a CMS-approved registry or study.^7,8 The doctor sends data at the start and then every six months for up to two years. This rule dates from 2022, and the CMS page, last updated in March 2026, still lists it.⁸ Ask whether your doctor or clinic takes part.

Other help:

• Medigap (supplement) plans help pay Original Medicare costs such as coinsurance.¹⁰
• Medicaid can pay the 20% for people who have both Medicare and Medicaid, or who are in a Medicare Savings Program.⁶
• The Alzheimer's Association lists a copay help program from the drug maker. Ask the clinic whether it applies to your insurance.⁶
• Private insurance coverage depends on your plan.⁶

See paying for new Alzheimer's drugs for more.

Tips for families

• Keep a shared calendar of infusion and MRI dates. A memory notebook can hold the medicine list and symptoms to report.
• Carry a card or phone note that says the person takes donanemab.
• Ask for a free medical interpreter if English is not your first language.
• Plan for the care partner's rest too. See caregiver burnout.

The Alzheimer's Association 24/7 Helpline at 800-272-3900 can answer questions about treatment.⁶

Questions to ask the doctor

Is donanemab a good fit for us?

• Is the diagnosis Alzheimer's, and is it still in the mild stage?
• How was amyloid confirmed? Do we need a PET scan or spinal fluid test?
• Do any of my health problems, past MRI findings or medicines make it unsafe?
• Why donanemab instead of lecanemab, or no anti-amyloid drug at all?

What are my personal risks?

• Should I have an APOE test? What will the result change?
• Will I start on the slower 2025 schedule?
• I take aspirin, a blood thinner or supplements. Is that a problem?
• Who do we call if symptoms appear at night or on a weekend?

How will we know when to stop?

• When will you check amyloid with a PET scan?
• What happens if the disease moves past the mild stage first?
• How will you follow us after the last infusion?
• Is your clinic in a Medicare-approved registry, and what will the whole course cost us?

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.