Creator: Help Dementia Editorial Team
Published: 2026-04-04T05:39:59

Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.

Slow decline sits at the center of this dementia and brain health question.

Yes, donanemab—marketed as Kisunla by Eli Lilly—is now available to Medicare recipients and is the most effective disease-modifying Alzheimer’s treatment approved to date. In Phase 3 clinical trials, the drug slowed cognitive decline by 35% in people with early-stage Alzheimer’s disease and mild cognitive impairment, compared to a placebo group.

Medicare began covering the drug in 2024 for eligible patients, meaning millions of Americans with a Medicare card and an early Alzheimer’s diagnosis may now have access to this treatment if they meet specific criteria. For someone like Margaret, a 72-year-old with mild cognitive impairment and documented brain amyloid, donanemab represents a concrete option to potentially slow the progression of memory and thinking problems over the coming years. This article explains what donanemab is, how it works, who qualifies for Medicare coverage, what it costs, and what to expect if you or a loved one are considering this treatment.

What Is Donanemab and How Does It Work Against Alzheimer’s Disease?
Does a 35% Decline Reduction Actually Stop Alzheimer’s?
Who Qualifies for Medicare Coverage of Donanemab?
What Does Donanemab Cost, and What Will Medicare Patients Pay?
What Are the Risks and Monitoring Requirements for Donanemab?
How Do You Access Donanemab if You Think You’re Eligible?
The Evolving Landscape of Alzheimer’s Disease Treatment
Conclusion

What Is Donanemab and How Does It Work Against Alzheimer’s Disease?

Donanemab is a monoclonal antibody—a type of medication that targets a specific protein in the brain. In this case, it targets amyloid-beta, a sticky protein that accumulates in the brains of people with Alzheimer’s disease, forming plaques that are believed to damage nerve cells and contribute to cognitive decline. By binding to these amyloid plaques and clearing them, donanemab appears to slow the rate at which memory and thinking abilities decline. The drug is administered as an intravenous infusion, typically given every four weeks once a patient reaches the full maintenance dose, though the initial treatment phase includes a titration period to allow the body to adjust.

The clinical evidence supporting donanemab comes from a large Phase 3 trial that followed people with mild cognitive impairment or mild dementia for 18 months. Those who received donanemab showed a 35% slowing of cognitive decline compared to those who received placebo—a meaningful difference in a disease where cognitive decline is the primary threat to independence and quality of life. For comparison, lecanemab (Leqembi), another recently approved amyloid-targeting drug, slows decline by approximately 27%, making donanemab the more potent option based on current data. However, it’s crucial to understand that a 35% slowing of decline does not mean a 35% improvement in memory or thinking—it means the rate of deterioration is reduced by that percentage, which translates to gaining several months of preserved cognitive function compared to the untreated course.

What Is Donanemab and How Does It Work Against Alzheimer's Disease?

Does a 35% Decline Reduction Actually Stop Alzheimer’s?

No. Donanemab slows cognitive decline but does not halt it or reverse existing damage. In the clinical trial, patients on donanemab still experienced cognitive decline; the drug simply reduced the speed at which it occurred. This distinction is critical: donanemab is not a cure and should not be framed as one. A person taking the drug will likely continue to notice gradual changes in memory, word-finding, or executive function, but ideally at a slower pace.

For patients in the early stages of the disease, this slower progression can mean more months or years of independence, clearer thinking, and active participation in daily life. The effectiveness of donanemab depends heavily on timing. It works best in people with mild cognitive impairment or mild dementia—the earliest stages of symptomatic Alzheimer’s disease. If administered when cognitive decline is already moderate to severe, the drug is less likely to provide meaningful benefit. This is why early diagnosis and enrollment in a registry to access the drug is so important; waiting until symptoms are obvious may mean missing the window of maximum effectiveness. Additionally, not everyone with Alzheimer’s disease has amyloid plaques as the primary driver of their cognitive decline, which is why confirmation of brain amyloid through imaging or biomarkers is a requirement for Medicare coverage.

Who Qualifies for Medicare Coverage of Donanemab?

Medicare covers donanemab for patients who meet four specific criteria. First, you must be enrolled in Medicare. Second, you must have a diagnosis of either mild cognitive impairment due to Alzheimer’s disease or mild dementia stage Alzheimer’s disease—confirmed by a clinician. Third, you must have documented evidence of beta-amyloid plaque in your brain, confirmed through either positron emission tomography (PET) imaging or cerebrospinal fluid biomarkers. Fourth, your prescribing physician must be participating in a CMS-qualified registry that includes appropriate clinical support, neuroimaging capability, and monitoring protocols. This registry requirement is essential to Medicare’s coverage policy. The registry ensures that patients are monitored for adverse effects, particularly amyloid-related imaging abnormalities (ARIA), which can develop in some people taking amyloid-targeting drugs.

Participating physicians are typically neurologists, geriatricians, or other specialists with experience in Alzheimer’s disease management. If you’re interested in donanemab, you’ll need to work with a healthcare provider who participates in an approved registry—calling your neurologist’s office or your local Alzheimer’s Association chapter can help you identify eligible providers in your area. An example: Robert, age 74, recently noticed he’s becoming forgetful in ways that concern him and his family. His internist refers him to a neurologist, who administers cognitive testing and orders amyloid PET imaging. The imaging shows clear amyloid accumulation, and Robert receives a diagnosis of mild cognitive impairment due to Alzheimer’s disease. His neurologist is enrolled in a Medicare-approved donanemab registry and has an infusion center on-site. Robert is eligible, and Medicare can help cover the cost of the drug.

Who Qualifies for Medicare Coverage of Donanemab?

What Does Donanemab Cost, and What Will Medicare Patients Pay?

The manufacturer’s price for donanemab is $32,000 per year. Once you’ve met your Medicare Part B deductible (which is $240 per year in 2026), you’ll typically pay 20% coinsurance of the Medicare-approved amount for each infusion. For most patients, this means a per-infusion cost of a few hundred dollars, with the exact amount depending on the Medicare-approved rate and your provider’s location. If you’re enrolled in a Medigap (supplemental insurance) plan, your supplemental plan may cover some or all of the 20% coinsurance. For patients who are dually eligible for both Medicare and Medicaid, Medicaid can cover the 20% coinsurance that Medicare leaves unpaid, effectively reducing out-of-pocket costs to nothing beyond the initial Medicare deductible.

This is significant for lower-income seniors, as it removes a major financial barrier. For those without supplemental coverage or Medicaid, the annual out-of-pocket cost ranges from roughly $1,000 to $2,000, depending on the Medicare-approved amount and your specific treatment frequency. Eli Lilly also offers patient assistance programs for those who have difficulty affording their coinsurance, though eligibility requirements apply. Compare this to the cost of untreated or delayed-treatment Alzheimer’s disease, which often leads to earlier nursing home placement, in-home care, or adult day programs—costs that can exceed $100,000 per year. While donanemab is expensive, the potential to delay cognitive decline may reduce downstream care costs and preserve a person’s independence for longer.

What Are the Risks and Monitoring Requirements for Donanemab?

The primary concern with amyloid-targeting monoclonal antibodies like donanemab is amyloid-related imaging abnormalities (ARIA). ARIA comes in two forms: ARIA-E (amyloid-related imaging abnormalities—edema, or brain swelling) and ARIA-H (amyloid-related imaging abnormalities—hemorrhage, or microhemorrhages). In clinical trials, some patients experienced these imaging findings, though many had no symptoms. Symptomatic ARIA is less common but can include headache, confusion, vision changes, nausea, or seizures. Because of this risk, Medicare requires that patients receive regular MRI scans during treatment—typically before starting the drug, before the maintenance dose, and periodically during treatment.

Your physician will also monitor you for any new cognitive or neurological symptoms and may adjust or discontinue the drug if concerning imaging changes develop. People taking blood thinners like warfarin may face increased risk of ARIA-H and require closer monitoring. Similarly, if you have a history of microhemorrhages, multiple brain infarcts, or certain bleeding disorders, donanemab may not be appropriate for you, and your physician will need to weigh the risks and benefits carefully. The requirement for regular MRI imaging is not trivial: it adds cost (typically $1,000 to $2,500 per scan, though Medicare covers most of the cost), time, and inconvenience, and some people with claustrophobia or metal implants may not tolerate the scans. These monitoring demands mean that donanemab is best suited for patients who can reliably attend appointments and tolerate repeated imaging.

What Are the Risks and Monitoring Requirements for Donanemab?

How Do You Access Donanemab if You Think You’re Eligible?

The pathway to donanemab involves several steps. First, if you haven’t already, schedule an appointment with a neurologist or other Alzheimer’s specialist. If you don’t have a neurologist, ask your primary care doctor for a referral, or contact the Alzheimer’s Association at 1-800-272-3900 to find specialists in your area. During your first visit, the neurologist will perform cognitive testing, review your medical history, and discuss whether Alzheimer’s disease evaluation is warranted. If cognitive testing suggests mild cognitive impairment or mild dementia, the next step is confirmation of amyloid pathology.

This is done through PET imaging or, in some cases, blood biomarkers (phosphorylated tau and amyloid-beta in the blood). PET imaging is more definitive but is less commonly covered by insurance; blood biomarkers are increasingly available and often easier to access. If amyloid is confirmed, your neurologist will discuss treatment options, including donanemab. If your neurologist participates in a Medicare-approved registry, you can proceed with enrollment and treatment. If they don’t, you may need to transfer care to a registry-participating physician or center, which may require travel if you live in a rural area.

The Evolving Landscape of Alzheimer’s Disease Treatment

For decades, Alzheimer’s disease had no disease-modifying treatments—drugs that slowed or altered the underlying disease process. Medications like donepezil (Aricept) only managed symptoms temporarily and didn’t change the disease trajectory. The approval of lecanemab in 2023 and donanemab in 2024 marked a watershed moment, ushering in an era of disease-modifying therapies based on removing amyloid from the brain.

However, amyloid removal is not the only approach in development; other Alzheimer’s drugs are targeting tau (another brain protein implicated in neurodegeneration), neuroinflammation, and other biological pathways. Looking ahead, researchers are studying whether combination therapies—using donanemab or lecanemab alongside other agents—might provide greater benefit than a single drug alone. There’s also interest in identifying and treating amyloid pathology even earlier, in people who have amyloid accumulation but no cognitive symptoms yet, to see if prevention is possible. While these advances are promising, they’re not yet standard of care; for now, donanemab and lecanemab represent the most substantive progress in disease modification that Alzheimer’s medicine has achieved.

Conclusion

Donanemab represents a meaningful advance in Alzheimer’s disease treatment, offering a 35% slowing of cognitive decline in people with early-stage disease and documented brain amyloid. For Medicare recipients who meet the eligibility criteria—mild cognitive impairment or mild dementia, amyloid confirmation, and access to a registry-participating physician—the drug is now a covered treatment option with manageable costs and known safety monitoring protocols. The drug is not a cure, and it works best when started early, but for people in the window of early symptomatic disease, it offers a concrete way to potentially preserve cognitive function and independence for several additional months.

If you suspect you or a loved one may have mild cognitive impairment or early Alzheimer’s disease, the first step is a conversation with a healthcare provider who can arrange appropriate testing and specialist referral. Time matters in Alzheimer’s disease, not because the disease progresses dramatically in weeks, but because the window of maximum treatment effectiveness is limited to the early stages. Starting donanemab or another disease-modifying therapy during this window may make a measurable difference in quality of life and functional independence over the coming years.