Leqembi is the first therapy to clearly slow cognitive decline in early Alzheimer’s. Here’s a straightforward guide to its benefits, risks, eligibility, and access, so you can understand where it fits into your treatment plan.
Leqembi (lecanemab) is a lab-made antibody that targets amyloid-beta: the protein that clumps into plaques in Alzheimer’s disease. By binding to toxic amyloid forms (including protofibrils) and helping clear plaques, it aims to slow the progression of Alzheimer’s rather than simply masking symptoms.
Results from the pivotal Clarity AD Phase 3 study (1,795 people with early Alzheimer’s) showed a 27% slower rate of clinical decline over 18 months vs. placebo, measured on the CDR-SB scale. Experts describe this as modest but meaningful at a population level.
In the big picture, Leqembi leads to more higher-quality time with better functioning, although day-to-day changes may be subtle.
In the U.S., treatment is recommended in people with early-stage Alzheimer’s with confirmed amyloid pathology (via PET scan or CSF testing). Appropriate-use recommendations and labeling emphasize confirming amyloid before starting therapy.
In Europe, the marketing authorization (April 15, 2025) limits use to adults with early Alzheimer’s who are ApoE4 non-carriers or heterozygotes (0 or 1 copy) and who have amyloid plaques. This reflects amyloid related imaging abnormality (ARIA) risk management; clinicians also have defined MRI checkpoints during treatment.
ApoE4 status matters everywhere: people with two ApoE4 copies have higher rates of ARIA and are counseled carefully. Many centers discuss genetic testing before treatment.
Leqembi is delivered as an intravenous infusion about once every two weeks. Each infusion typically takes ~1 hour in a clinic or infusion center. After the initial 18-month period, regulators have cleared a monthly maintenance option (every four weeks), which some programs may adopt as capacity, protocols, and needs evolve.
Because of ARIA risk (more on that below), patients are required to undergo MRI scans before starting and periodically during treatment. Furthermore, programs may adjust timing based on local protocols and any symptoms that arise.
The most important risks involve:
Most ARIA is symptom-free and detected on MRI, but serious events, including rarely life-threatening cases, can occur. The U.S. label carries a boxed warning for ARIA and highlights higher risk in ApoE4 homozygotes and caution for patients on anticoagulants.
Infusion reactions are also common, especially with early doses (e.g., flu-like symptoms, fever, blood pressure changes). Teams can slow/stop an infusion and pre-medicate for future visits if needed.
What you need to watch for: new or worsening headaches, confusion, dizziness, vision changes, trouble walking, seizures. If you’re experiencing any of these after starting Leqembi, report it immediately and get assessed.
Health systems are building coordinated pathways: verifying diagnosis and amyloid status, scheduling MRIs, arranging infusions, and educating patients about safety. Early rollout has been cautious; sites report a staged ramp as processes solidify and as payers finalize coverage rules.
Curious how AI is accelerating neuroscience? Read our blog to see how data science is reshaping Alzheimer’s discovery and treatment access.
The list price for Leqembi is about $26,500 per year for the drug alone.
Under Medicare Part B, many beneficiaries face 20% coinsurance after the deductible. Real-world costs are going to depend on supplemental coverage and infusion / scan fees. Commercial policies will vary.
Coverage has broadened since full Leqembi FDA approval (and will likely continue to expand), but access to Leqembi still depends on each plan’s policies. Medicare covers the drug more broadly now that the FDA-granted traditional approval, with clinicians entering basic patient information into a CMS registry to build real-world evidence.
Families should also budget for diagnostic PET or CSF testing and MRIs over time.
Aduhelm (aducanumab): This earlier anti-amyloid antibody reduced plaques but showed uncertain clinical benefit across trials, limiting uptake. By contrast, Leqembi demonstrated a consistent clinical effect in a large Phase 3 study, though the size of the benefit remains modest.
Donanemab (Kisunla): Donanemab also targets amyloid and received FDA approval in 2024 for early symptomatic Alzheimer’s. It’s typically dosed monthly and, like Leqembi, carries ARIA risk and requires MRI monitoring. Head-to-head data is not available, and the choice between the two often hinges on logistics, center experience, payer coverage, and patient preference.
The United States. Accelerated approval came in January 2023, with full approval in July 2023, unlocking broader Medicare coverage.
The European Union. The EU granted marketing authorization on April 15, 2025 for adults with early Alzheimer’s who are ApoE4 non-carriers or heterozygotes and amyloid-positive, under enhanced risk-minimization measures.
Lecanemab has also been approved in several countries, including Japan, China, South Korea, Great Britain, Hong Kong, Israel, and the UAE. Local labels and reimbursement varies by market.
Two trends to watch for:
Eisai has submitted data for an under-the-skin formulation that could make ongoing dosing simpler and reduce infusion-center bottlenecks if approved.
Studies such as AHEAD are testing anti-amyloid therapy in people with elevated amyloid but no symptoms yet. Health systems are also piloting blood-based biomarkers to speed initial screening, with confirmatory PET/CSF used before treatment decisions.
No Alzheimer’s drug had shown verified disease-slowing benefit for decades. Leqembi changes that, delivering a modest but significant slowing of decline for people in the early stage. Leqembi therapy brings real responsibilities (confirming amyloid, monitoring for ARIA, and navigating coverage), but it also brings more time at better function for many patients.
If you’re interested, talk with a specialist team about eligibility, safety, and fit with your goals of care.
The team at Daugherty partners with healthcare leaders and life-science innovators to stand up evidence-based patient pathways, data pipelines for real-world evidence, and human-centered digital experiences that improve access and outcomes.
If you’re exploring Leqembi programs or building the data and AI foundation for next-generation Alzheimer’s care, reach out. We’d love to compare notes and help you move faster, safely.
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