For the first time in the history of Alzheimer’s treatment, drugs exist that actually slow the underlying disease rather than just masking symptoms. Lecanemab, sold as Leqembi, became the first traditionally approved disease-modifying Alzheimer’s drug in July 2023, and donanemab, marketed as Kisunla, followed with FDA approval in July 2024. These monoclonal antibody therapies work by clearing toxic amyloid-beta plaques from the brain, and clinical trials have shown they can slow cognitive decline by roughly 27 to 29 percent compared to placebo. That may not sound dramatic on paper, but it represents a fundamental shift: we are no longer limited to drugs that temporarily boost memory signals while the disease burns unchecked underneath. This distinction matters enormously to the millions of families navigating an Alzheimer’s diagnosis.
Previous medications like donepezil and memantine offered symptomatic relief at best, doing nothing to address the plaques and tangles destroying brain tissue. The new therapies are not cures, and they come with serious risks including brain swelling and bleeding. But they mark the first time the medical establishment can point to a treatment and say it is changing the trajectory of the disease itself. Consider the Clarity AD trial, published in the New England Journal of Medicine, which demonstrated that lecanemab slowed decline enough that patients retained measurably more of their daily functioning over 18 months than those on placebo. This article breaks down how these disease-modifying drugs work, what the clinical evidence actually shows, who qualifies for treatment, the real costs and safety concerns involved, and what emerging research suggests about where Alzheimer’s treatment is headed next.
Table of Contents
- How Are These New Alzheimer’s Drugs Actually Slowing the Disease Instead of Just Managing Symptoms?
- Leqembi vs. Kisunla — Comparing the Two Approved Treatments
- What Treatment Actually Costs and Who Pays for It
- Who Actually Qualifies and What the Treatment Process Looks Like
- The ARIA Risk — What Patients and Families Need to Understand
- International Access and Approval Status
- What Is Coming Next in Alzheimer’s Drug Research
- Conclusion
- Frequently Asked Questions
How Are These New Alzheimer’s Drugs Actually Slowing the Disease Instead of Just Managing Symptoms?
The mechanism behind lecanemab and donanemab is fundamentally different from older Alzheimer’s medications. Donepezil, for example, works by preventing the breakdown of acetylcholine, a neurotransmitter involved in memory. It boosts signaling in a brain that is actively deteriorating, which is why its benefits plateau and then fade as the disease progresses. Lecanemab and donanemab, by contrast, are monoclonal antibodies that target amyloid-beta protein, one of the key pathological hallmarks of Alzheimer’s disease. Lecanemab specifically binds to soluble amyloid-beta oligomers and protofibrils, the forms thought to be most toxic to neurons, and clears them from brain tissue and cerebrospinal fluid. Donanemab targets a modified form of amyloid-beta found in established plaques. The practical difference shows up in trial data.
In the Clarity AD phase 3 trial, lecanemab slowed cognitive decline by approximately 27 percent versus placebo over 18 months. Donanemab’s TRAILBLAZER-ALZ 2 trial showed a 28.9 percent reduction in cognitive decline, corresponding to a 4.5 to 7.5 month delay in disease progression. These are not remissions or reversals. Patients on these drugs still decline, just more slowly. But for a disease that relentlessly strips away independence, a delay of several months in reaching the next stage of impairment is meaningful to patients and to the families who care for them. It is worth noting that both drugs only work in early-stage Alzheimer’s, specifically in people with mild cognitive impairment or mild dementia who have confirmed elevated amyloid-beta levels. They have not been tested or approved for moderate or advanced Alzheimer’s, and there is no evidence they would help at those stages. The amyloid hypothesis, while supported by this trial data, remains contested by some researchers who argue that plaque clearance alone does not fully explain the modest clinical benefits observed.
Leqembi vs. Kisunla — Comparing the Two Approved Treatments
Lecanemab and donanemab are often discussed together, but they differ in important ways that affect which drug a patient and their physician might choose. Lecanemab requires biweekly intravenous infusions as its standard regimen, though a subcutaneous version called Leqembi IQLIK was approved by the FDA on August 29, 2025, and launched in the United States on October 6, 2025. That version is a 360 mg autoinjector administered weekly in roughly 15 seconds for maintenance dosing, a significant convenience improvement. Donanemab is given as a monthly IV infusion for up to 18 months, and notably, patients may be able to stop treatment after as few as 9 months if imaging confirms that amyloid clearance has reached a sufficient threshold. The safety profiles diverge significantly. Lecanemab caused brain swelling, known as ARIA-E, in about 13 percent of trial participants and brain bleeding, or ARIA-H, in about 17 percent versus 9 percent in the placebo group.
No deaths were attributed to lecanemab in the core Clarity AD study. Donanemab’s ARIA rates were substantially higher: brain swelling in approximately 24 percent of participants and brain bleeding in around 31 percent, with 3 deaths attributed to ARIA across four trials. A 2025 indirect comparison study confirmed that lecanemab carried significantly lower ARIA and intracranial hemorrhage-related mortality risk compared to donanemab. However, if a patient is someone who would strongly prefer a finite treatment course rather than ongoing infusions, donanemab’s time-limited approach may be attractive despite the higher ARIA risk. Conversely, patients who are ApoE4 carriers, a genetic variant carried by roughly 25 percent of the population and present at much higher rates among Alzheimer’s patients, face amplified risks with either drug. Research shows ApoE4 carriers have a 2.19 times higher risk of ARIA-E and a 3.45 times higher risk of ARIA-H compared to non-carriers, making the safety conversation especially critical for this group.
What Treatment Actually Costs and Who Pays for It
Cost is one of the most contentious aspects of these new treatments, and not just because the drugs themselves are expensive. Leqembi IQLIK, the subcutaneous autoinjector, carries a list price of $375 per injection, or approximately $19,500 annually. Donanemab costs roughly $32,000 per year for a person of average weight. But the sticker price understates the true financial burden. Patients also need amyloid-PET scans or cerebrospinal fluid tests to confirm eligibility, genetic testing to assess ApoE4 status, and serial MRI scans to monitor for ARIA, all of which add thousands of dollars to the overall treatment cost. For patients on Medicare, there is some relief.
The Inflation Reduction Act’s $2,000 annual out-of-pocket cap under Medicare Part D applies to these drugs, which means most Medicare beneficiaries would not pay more than $2,000 per year regardless of the list price. The subcutaneous version of lecanemab also offers meaningful savings beyond convenience. Projections suggest it could save between $72,891 and $80,925 per patient over four years compared to IV Leqembi, primarily by eliminating the need for infusion center visits, reducing nursing time, and cutting associated facility fees. For those without Medicare or with private insurance, coverage remains inconsistent. Some private insurers have been slow to cover these drugs, citing the modest efficacy data and the high overall treatment costs. Patients considering these therapies should contact their insurance provider early in the process and ask specifically about prior authorization requirements and coverage for the associated monitoring.
Who Actually Qualifies and What the Treatment Process Looks Like
Not everyone with Alzheimer’s disease is a candidate for these treatments, and this is a point that frequently causes frustration for families. Both lecanemab and donanemab are approved only for early symptomatic Alzheimer’s disease, meaning patients must have mild cognitive impairment or mild-stage dementia. Additionally, patients must have confirmed elevated amyloid-beta in the brain, verified either through a PET scan or a lumbar puncture for cerebrospinal fluid biomarkers. Someone with moderate or advanced Alzheimer’s, no matter how desperately their family wants access, does not qualify. The treatment process for lecanemab typically begins with the biweekly IV infusion regimen. After an initial loading period, eligible patients may transition to the weekly subcutaneous autoinjector for maintenance. MRI monitoring is required before and during treatment to watch for ARIA, typically at set intervals during the first several months.
With donanemab, treatment involves monthly IV infusions, with PET scans at around 6 to 9 months to assess whether enough amyloid has been cleared to discontinue. If the threshold is reached, treatment stops, which is unique among current options. The tradeoff patients face is real. Starting treatment means committing to regular medical visits, imaging, and living with the possibility of side effects that, while usually asymptomatic, can in rare cases be serious or fatal. For patients in the earliest stages who are otherwise healthy, the risk-benefit calculation often favors treatment. For those with significant comorbidities, blood-thinning medications, or who are homozygous ApoE4 carriers, the conversation becomes more cautious. Physicians specializing in these treatments emphasize that each decision must be individualized.
The ARIA Risk — What Patients and Families Need to Understand
ARIA, or amyloid-related imaging abnormalities, is the most significant safety concern with both lecanemab and donanemab. ARIA-E refers to brain swelling or edema, while ARIA-H refers to microbleeds or larger hemorrhages. Most ARIA events are detected on routine MRI monitoring and produce no symptoms. But in a subset of cases, ARIA can cause headaches, confusion, dizziness, visual disturbances, nausea, or in severe cases, seizures and hospitalization. The critical warning for families involves ApoE4 genetics. Patients who carry two copies of the ApoE4 allele, known as homozygous carriers, face substantially elevated ARIA risk.
The 2.19-fold increase in ARIA-E risk and 3.45-fold increase in ARIA-H risk for ApoE4 carriers compared to non-carriers means that genetic testing is not optional, it is essential before starting either drug. In the donanemab trials, the 3 deaths attributed to ARIA underscore that while rare, the worst outcomes are not theoretical. Clinicians generally recommend against treating homozygous ApoE4 carriers with donanemab and exercise significant caution with lecanemab in that population. Real-world data that has accumulated since lecanemab’s approval offers some reassurance: side effect rates in clinical practice appear to be lower than what was observed in trials. This may reflect better patient selection, more careful monitoring, or the tendency for clinical trials to detect events that might go unnoticed in routine care. Regardless, families should understand that ARIA monitoring requires strict adherence to the MRI schedule, and any new neurological symptoms during treatment should prompt immediate medical evaluation.
International Access and Approval Status
The availability of these drugs varies widely by country, creating disparities that are hard for families to navigate. Lecanemab has been approved in Canada as of October 25, 2025, under Health Canada, and is available in the United States and Japan. Donanemab has gained approval in Japan as of September 2024, the United Kingdom in October 2024, China in December 2024, and the European Union in September 2025. However, approval does not always mean access.
The UK’s NHS, for instance, has declined to cover donanemab despite its regulatory approval, citing concerns about cost-effectiveness and the infrastructure needed for safe administration, including widespread access to PET scanning and MRI monitoring. This pattern of regulatory approval without reimbursement is becoming a flashpoint globally. Families in countries with national health systems may find that the drug is technically approved but functionally unavailable unless they can pay out of pocket or access it through private care. The situation highlights a broader challenge: disease-modifying Alzheimer’s treatments require an ecosystem of diagnostic imaging, genetic testing, and specialized neurology care that many healthcare systems have not yet built out.
What Is Coming Next in Alzheimer’s Drug Research
The current approved drugs are likely just the beginning of a new era in Alzheimer’s treatment. Several developments in 2025 and 2026 suggest the field is accelerating. Researchers at Northwestern University published findings in February 2026 showing that levetiracetam, an existing FDA-approved anti-seizure medication, can prevent toxic amyloid-beta peptide production entirely, a fundamentally different approach from current drugs that only clear plaques after they have formed. If this finding holds up in human trials, it could shift the treatment paradigm from clearance to prevention.
Other promising research includes NU-9, an experimental compound that blocks early neuronal damage in mice and reduces inflammation linked to disease progression, and trontinemab, a Roche-developed antibody engineered to cross the blood-brain barrier more effectively than current treatments, which is now in clinical trials. Indiana University researchers also identified a promising new drug target pathway for Alzheimer’s in February 2026. None of these are ready for patients yet, but they represent a pipeline that did not exist five years ago. The trajectory is clear: the era of treating Alzheimer’s as an untouchable disease is over, though the era of truly effective treatment is still being built, one hard-won trial at a time.
Conclusion
Lecanemab and donanemab represent a genuine turning point in Alzheimer’s treatment, the first therapies that modify the course of the disease rather than temporarily propping up failing brain chemistry. The clinical benefits are modest, roughly a quarter reduction in the rate of cognitive decline, and the treatments come with real risks, significant costs, and strict eligibility requirements. But for patients in the early stages of Alzheimer’s who meet the criteria, these drugs offer something that was not available even three years ago: a way to slow what was previously an entirely unstoppable process.
Families considering these treatments should start with a neurologist experienced in amyloid-targeting therapies, ensure appropriate diagnostic testing including amyloid confirmation and ApoE4 genotyping, and have an honest conversation about individual risk factors and goals. The subcutaneous formulation of lecanemab has made treatment more accessible and less burdensome, and ongoing research suggests that better, safer, and potentially preventive therapies are on the horizon. This is not a moment for false hope, but it is a moment for cautious, informed optimism about where Alzheimer’s care is heading.
Frequently Asked Questions
Are these new Alzheimer’s drugs a cure?
No. Lecanemab and donanemab slow the rate of cognitive decline by approximately 27 to 29 percent, but they do not stop or reverse the disease. Patients on these drugs still experience progression, just at a slower pace.
Who is eligible for lecanemab or donanemab?
Only patients with early symptomatic Alzheimer’s disease, either mild cognitive impairment or mild dementia, who have confirmed elevated amyloid-beta levels in the brain. Patients with moderate or advanced Alzheimer’s are not eligible.
How much do these treatments cost out of pocket?
Leqembi IQLIK, the subcutaneous version of lecanemab, lists at approximately $19,500 per year. Donanemab costs roughly $32,000 per year. Medicare Part D patients are capped at $2,000 per year in out-of-pocket costs. Additional expenses for PET scans, genetic testing, and MRI monitoring apply.
What is ARIA and how dangerous is it?
ARIA stands for amyloid-related imaging abnormalities, which include brain swelling and microbleeds. Most cases are detected on routine MRI and cause no symptoms. However, serious cases can cause headaches, confusion, seizures, and in rare instances with donanemab, death. ApoE4 gene carriers face significantly higher ARIA risk.
Can I take these drugs at home instead of going to an infusion center?
Leqembi IQLIK, the subcutaneous autoinjector approved in August 2025, allows weekly self-administration at home for maintenance dosing after an initial IV loading period. Donanemab currently requires monthly IV infusions at a medical facility.
Is there anything on the horizon that could prevent Alzheimer’s rather than just slow it?
Researchers at Northwestern University found in February 2026 that levetiracetam, an existing anti-seizure drug, may prevent toxic amyloid-beta production entirely rather than clearing plaques after they form. This is still in early research stages and not yet available as a treatment.
