Leqembi and Medicare: Coverage for New Alzheimer's Drugs

For decades, Alzheimer's treatment meant managing symptoms rather than the disease itself. A newer class of drugs has changed that conversation. Leqembi, known generically as lecanemab, and similar anti-amyloid infused drugs target the underlying disease process in people with early Alzheimer's. Medicare covers these drugs, but with specific conditions attached, and because they are expensive infused medications, what you pay and how your supplemental coverage protects you deserve careful attention. If you or a loved one is considering one of these therapies, here is how Medicare handles it.

Bryce's Take

The new Alzheimer's drugs are a genuine medical development, but the coverage picture is one families do not expect. It is a Part B infused drug with a registry requirement, ongoing MRI monitoring, and a 20 percent coinsurance that has no ceiling on Original Medicare alone. When a family calls me about starting Leqembi, the first thing I check is whether their supplemental coverage, Medigap or an Advantage out-of-pocket maximum, actually caps that exposure. For a long course of an expensive infused drug, that protection matters enormously. Let us look at it before treatment starts.

How Medicare covers Leqembi

Because Leqembi is administered by infusion in a clinical setting, Medicare covers it under Part B, the medical side, not Part D. Medicare covers these anti-amyloid drugs under a framework called coverage with evidence development, which means coverage is tied to the drug being used within an approved patient registry that collects real-world data on how patients do. In practice, your provider participates in the registry as part of prescribing the drug. This is different from most Part B drugs, and it is worth understanding going in that registry participation is part of how coverage works for this class.

The clinical requirements

Coverage for these drugs comes with clinical criteria intended to match the drug to appropriate patients and to monitor for side effects. Broadly, that includes confirmation of amyloid in the brain, since the drugs target amyloid, and a diagnosis in the early stages of the disease, because that is the population studied. Because these drugs can cause brain swelling or small bleeds in some patients, regular MRI monitoring is part of the treatment protocol to catch and manage side effects. Your neurologist manages these requirements, but knowing they exist helps you understand what treatment involves.

The 20 percent coinsurance is substantial

Like other Part B drugs, these anti-amyloid infusions carry 20 percent coinsurance after the Part B deductible under Original Medicare. Because the drugs are expensive and given on an ongoing schedule, 20 percent of the cost can be a significant amount over a year, and there are the associated costs of infusions and the MRI monitoring on top of the drug itself. Original Medicare alone places no annual cap on that 20 percent, so without additional coverage the exposure can be considerable for a full course of treatment.

Why Medigap or an Advantage cap matters here

This is exactly the situation where supplemental coverage earns its keep. With Original Medicare plus a comprehensive Medigap plan like Plan G, the plan generally covers the 20 percent Part B coinsurance, which can bring your cost for the drug and the associated Part B services down close to zero after the deductible. With a Medicare Advantage plan, the cost-sharing runs through the plan and counts toward its annual out-of-pocket maximum, which caps your total exposure. For an expensive ongoing infused drug like this, that protection is the difference between manageable and overwhelming costs.

What this means for coverage decisions

If an anti-amyloid Alzheimer's drug is on the table, the coverage question is not only whether Medicare covers it, since it does under Part B with the registry framework, but how your supplemental coverage shields you from the 20 percent coinsurance and the monitoring costs. Your exact out-of-pocket cost depends on your specific treatment schedule and the coverage you carry. This is a case where reviewing your Medigap or Advantage protection before starting treatment can save real money and stress across a long course of therapy.

Bryce Casson

Licensed Independent Medicare Broker

Bryce Casson is an independent Medicare insurance broker who works with every major carrier. He does not represent any single insurer, which means his recommendations are based on what actually fits each client's situation, not on commissions or quotas.