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Does Medicare Cover Leqembi and Kisunla? The New Alzheimer's Drug Coverage Reality, Sioux Falls 2026

Medicare will pay for the new anti-amyloid drugs — but only through Part B, only for early-stage disease, and only after real hoops. Here's the actual math.

Big Sioux Benefits Data Desk

Published August 21, 2026 · 17 min read · Sourced from CMS.gov, Medicare.gov, Eisai Inc. & Eli Lilly

Yes, Medicare covers Leqembi and Kisunla — the two FDA-approved drugs that target amyloid plaque in early Alzheimer's disease — but only for a specific stage of the disease, only when a doctor confirms amyloid pathology, and only when the drug is billed through Medicare Part B rather than Part D. That last detail matters more than it sounds like it should, because it's the difference between a drug cost that's capped and one that isn't. This guide walks through exactly what's covered, why the billing pathway is the whole ballgame, what these drugs cost using each manufacturer's own 2026 pricing, and what a Sioux Falls-area family should actually do if a doctor raises this option.

Every figure below is pulled this week from a primary source: Medicare.gov's own coverage page for these drugs, CMS's National Coverage Determination and its 2022 fact sheet, CMS's July 2023 coverage statement, Eisai's own July 2026 product price list, Eli Lilly's own investor announcement, and the Alzheimer's Association's South Dakota data. No invented numbers, no "call for pricing." We're not doctors and this isn't medical advice — your neurologist makes the clinical call. Our job is the Medicare math once that conversation starts.

Does Medicare cover Leqembi and Kisunla? The short answer

Yes, for early-stage Alzheimer's disease specifically — not for every stage, and not automatically. Medicare Part B covers FDA-approved monoclonal antibodies that target amyloid plaque, which today means Leqembi (lecanemab) and Kisunla (donanemab-azbt), when your provider confirms a clinical diagnosis of mild cognitive impairment or mild dementia due to Alzheimer's disease, confirms the presence of amyloid pathology, and delivers the drug through a practice enrolled in a CMS-approved registry, according to Medicare.gov's coverage page for these drugs.

Medicare does not cover these drugs for moderate or severe Alzheimer's disease — the clinical trials behind both approvals only studied the early stage, and CMS's coverage criteria follow that evidence exactly. If your parent or spouse is further along in the disease, this specific coverage pathway will not apply, though the broader dementia coverage picture — cognitive assessments, care planning, the CMS GUIDE Model for caregiver support — still does. We covered that ground separately in our dementia and caregiver coverage guide; this article is specifically about the drugs themselves.

What Leqembi and Kisunla actually are

Both drugs are monoclonal antibodies — lab-made proteins engineered to find and clear a specific target in the body — aimed at beta-amyloid, the sticky protein that clumps into plaques in the brains of people with Alzheimer's disease. Neither drug cures Alzheimer's or reverses damage that's already occurred. Medicare's own coverage page is direct about this: they "may slow or delay symptoms of Alzheimer's disease, but they don't cure or reverse the disease."

• Leqembi (lecanemab-irmb), made by Eisai and Biogen, received FDA accelerated approval in January 2023 and full traditional approval on July 6, 2023, the date CMS confirmed broader Medicare coverage was available, per CMS's own statement that day. It's given as a biweekly IV infusion, and since 2025 has also been available as a weekly at-home subcutaneous injection called Leqembi IQLIK for patients transitioning to maintenance therapy.
• Kisunla (donanemab-azbt), made by Eli Lilly, was FDA-approved on July 2, 2024, according to Lilly's own investor announcement. It's given as a monthly, 30-minute IV infusion, and it's the only drug in this class designed around a limited-duration regimen — a doctor can consider stopping treatment once a PET scan shows amyloid plaques have dropped to minimal levels, which Lilly's own data shows happened for a meaningful share of patients well before 18 months.

Source: Eisai Inc. Product Price List, effective July 13, 2026, and Eli Lilly and Company investor announcement, July 2, 2024 (Kisunla course-of-therapy pricing).

Why Medicare treats this drug class differently

Both drugs are covered under one federal policy, not two: National Coverage Determination 200.3, which CMS finalized on April 7, 2022, before either drug had traditional FDA approval. It set up a framework called Coverage with Evidence Development (CED) — Medicare pays for the drug, but the treating clinician has to collect structured outcome data through a CMS-approved registry or study, so CMS keeps gathering real-world evidence on how the drug performs outside a clinical trial, per CMS's own fact sheet on the policy.

CMS built this policy before knowing which specific drugs would ultimately win full approval, which is why it applies automatically to "any anti-amyloid monoclonal antibody" that meets the same evidence standard — a deliberate, forward-looking design, according to CMS's own Q&A on the rule. That's also why a beneficiary doesn't need a new act of Congress or a new coverage decision every time a new drug in this exact class reaches the market; the pathway is already built.

Part B or Part D? Why the needle decides your bill

The single most important fact in this entire article is that Leqembi and Kisunla are Part B drugs, not Part D drugs — and that one routing decision changes your entire cost picture. Medicare draws that line based on how a drug is administered, not what condition it treats. A drug you swallow or self-inject at home is typically a Part D pharmacy benefit. A drug that has to be given by a clinician, in a clinic or infusion center, is typically a Part B medical benefit.

A $2,100 cap protects your pharmacy bag. It was never built to protect an infusion chair.

Both Leqembi's IV infusion and Kisunla's monthly infusion clear that Part B bar easily — they're given in a clinical setting by a provider. Even Leqembi IQLIK, the newer at-home subcutaneous version, stays under Part B's physician-administered-drug framework because a clinician directs the regimen, according to Medicare.gov's coverage page. That means the 2026 Part D out-of-pocket cap of $2,100 — the genuine, first-of-its-kind consumer protection we've covered in our Part D cap guide — does not apply here at all. These drugs run on Part B's older, uncapped 20%-coinsurance model instead, the same model that applies to the Part B injections and infusions we cover more broadly in that guide.

What these drugs actually cost in 2026

List price isn't what most patients pay, but it's the number every other calculation starts from — and it's risen since these drugs launched. Eisai set Leqembi's original 2023 launch price at $26,500 a year, calculated on 10mg/kg biweekly IV dosing for an average 75kg U.S. patient, at a wholesale acquisition cost of $254.81 for a 200mg vial and $637.02 for a 500mg vial, according to Eisai's own January 2023 pricing announcement. Eisai's current price list, effective July 13, 2026, shows those same two vial sizes now at $271.83 and $679.60 — a roughly 6.7% increase over three years, using Eisai's own published figures both times.

Kisunla works differently — it's built around a limited-duration course rather than indefinite dosing, so Eli Lilly publishes cost by treatment length instead of a flat annual figure. Its own investor materials from the drug's July 2024 FDA approval lay out three worked examples, priced at $695.65 per vial:

Source: Eli Lilly and Company, investor announcement, July 2, 2024. In the drug's own clinical trial population, 17% of patients completed treatment at 6 months, 47% at 12 months, and 69% at 18 months, based on amyloid PET imaging showing plaques had dropped to minimal levels.

That limited-duration design is Lilly's own selling point: a patient who clears plaques early can stop dosing and stop paying, at least for this drug. It's also a real reason a treating neurologist might lean toward one drug over the other for a specific patient — a clinical decision, not a Medicare one, and one worth discussing directly with the prescriber.

The real math: Original Medicare, Medigap, and Medicare Advantage

Your out-of-pocket exposure on these drugs depends entirely on which Medicare path you're on — far more than it depends on which of the two drugs you take. Medicare.gov is explicit about the cost-sharing rule for this drug class: after you meet the Part B deductible, you pay 20% of the Medicare-approved amount, with no built-in annual ceiling under Original Medicare alone.

Source: Medicare.gov 2026 cost rules; manufacturer pricing from Eisai Inc. (Jul 2026) and Eli Lilly and Company (Jul 2024). Coinsurance math applies 20% to each manufacturer's published list price — Medicare's actual approved amount is typically based on the drug's Average Sales Price, which can differ from the list price shown here, so treat these as directional estimates, not a bill.

Worked out in dollars: 20% of Leqembi's original $26,500 annual list price is $5,300. Twenty percent of Kisunla's published 12-month course cost of $32,000 is $6,400. Neither of those numbers has a ceiling under Original Medicare alone — unlike almost every other prescription drug cost a Medicare beneficiary deals with today, now that the $2,100 Part D cap exists. A Medigap Plan G supplement closes that specific gap by paying the Part B coinsurance in full, which is a meaningful part of why we walk every Medigap-vs-Advantage conversation through scenarios like this one, not just premium comparisons — see our full Medigap vs. Medicare Advantage guide.

The diagnostic gauntlet: PET scans, MRI, and ARIA

Getting the coverage question right is only half the picture — getting to the point of treatment involves its own real costs and its own real risks. Before Medicare will cover either drug, your provider has to confirm amyloid plaques are actually present, typically through an amyloid PET scan or a cerebrospinal fluid test, per Medicare.gov's eligibility rules for this coverage. CMS had previously limited amyloid PET scans to one per patient's lifetime under a separate coverage decision; Eli Lilly's own materials note that broad Medicare coverage and reimbursement for amyloid PET scans, without that old restriction, has been available since October 2023.

Treatment itself comes with a monitoring requirement, not just a diagnostic one. Both drugs carry an FDA boxed warning for Amyloid-Related Imaging Abnormalities (ARIA) — brain swelling or microbleeds that show up on MRI, usually without symptoms but occasionally serious, according to Leqembi's own published safety information. That means baseline and periodic brain MRIs are part of the treatment plan, not an optional extra, and each of those scans carries its own separate Part B cost-sharing on top of the drug itself.

If you're on a Medicare Advantage plan

The same national coverage rules apply everywhere in Medicare, including every Medicare Advantage plan — but Advantage plans are allowed to add their own prior authorization and network steps on top. That's standard practice for a high-cost Part B drug, not something specific to this drug class, and it means the first real step for an Advantage enrollee is confirming which infusion sites are in-network and whether the plan requires prior authorization before the first dose.

Sioux Falls' Medicare Advantage market runs through five standard PPOs open to anyone with Medicare in Minnehaha County, plus Dual-Eligible and Institutional Special Needs Plans and four Medica Cost plans, all detailed in our full local plan roster. Here are the five standard PPOs, for reference on what "the plans we offer" actually means in this county:

Source: CMS Medicare Advantage / Part D Landscape (PY2026) & CMS Medicare Advantage & Part D Star Ratings (2026), Minnehaha County, PY2026.

Every one of these plans, like every Medicare Advantage plan nationwide, is required to publish an annual Maximum Out-of-Pocket limit that caps your combined in-network Part A and B cost-sharing for the year — that figure, not the premium, is what actually protects you against an uncapped 20% coinsurance bill on a drug like Leqembi or Kisunla. We don't have a verified 2026 MOOP figure for each plan to publish here, and we'd rather send you to the real number than guess at one — ask us and we'll pull the current figure from the plan's own Summary of Benefits.

Minnehaha County's Alzheimer's numbers

This isn't an abstract policy question here. More than 17,000 South Dakotans 65 and older are living with Alzheimer's, supported by an estimated 29,000 unpaid family caregivers who together provide roughly 33 million hours of care a year — worth an estimated $910 million — according to the Alzheimer's Association's South Dakota data. The same data puts the direct cost of Alzheimer's disease to South Dakota's Medicaid program at $240 million.

Source: Alzheimer's Association — South Dakota state overview, most recent available data.

Minnehaha County alone carries 39,532 Medicare beneficiaries, and CDC PLACES data shows 22.3% of local adults carry a diagnosed depression condition — a figure worth knowing because caregiver strain and depression run closely together in the research literature, even without a county-specific Alzheimer's prevalence figure to cite directly.

Source: CMS Medicare Monthly Enrollment by County (2026) (2026) and CDC PLACES: Local Data for Better Health, County 2023 (2023).

Sioux Falls access: Sanford, Avera, and the registry question

Sioux Falls runs on two competing hospital systems, Sanford Health and Avera Health — Sanford USD Medical Center carries a 5-star CMS overall rating and Avera McKennan holds 4 stars, per CMS Hospital Compare. Which system your neurologist practices under, and whether that specific practice participates in a CMS-approved registry for Leqembi or Kisunla, decides whether treatment is realistically available to you locally at all.

Source: CMS Hospital Compare — Overall Star Ratings.

We want to be straightforward about what we could and couldn't verify this week: we did not find a public, confirmed source listing a specific Sioux Falls-area practice as an enrolled CED registry participant for these drugs, and CMS's list of approved studies changes over time. The honest, useful step is to ask directly — call your neurologist's office, or Sanford's or Avera's memory care program, and ask whether they currently offer Leqembi or Kisunla and which registry they use. We'll happily help you understand what a "yes" means for your specific plan's cost-sharing once you have that answer.

A practical checklist for this conversation

1. Confirm the diagnosis stage. Coverage applies to mild cognitive impairment or mild dementia due to Alzheimer's disease specifically — ask your doctor directly where things stand.
2. Ask about amyloid confirmation. A PET scan or spinal fluid test is required before treatment; ask which one your provider recommends and how Medicare will bill it.
3. Ask whether the practice is CED-registry enrolled. Not every neurology practice participates — this single question determines whether Medicare will pay at all.
4. Check which Medicare coverage you have. Original Medicare alone leaves 20% coinsurance uncapped; a Medigap Plan G supplement or a Medicare Advantage plan's MOOP changes that math completely.
5. Ask about the MRI monitoring schedule. ARIA monitoring means recurring brain MRIs — each with its own Part B cost-sharing — factor that into the full picture, not just the drug itself.
6. Bring us into the cost conversation. We can't make the medical call, but we can tell you exactly what your specific plan would owe once your doctor has a treatment plan in mind.

What to watch going into 2027

1. Whether a third anti-amyloid drug reaches FDA approval. NCD 200.3 was written to apply automatically to future drugs in this class that meet the same evidence standard — worth watching for new options.
2. Whether CMS narrows or expands the CED registry requirement. As more real-world data accumulates, CMS could eventually revisit the evidence-development requirement itself.
3. Manufacturer list price changes. Both companies have adjusted pricing since launch; check current figures before assuming last year's numbers still hold.
4. Your Medicare Advantage plan's prior-authorization rules for this drug class, which can change from one Annual Notice of Change to the next — worth a fresh check every fall.
5. Whether a Sioux Falls-area practice joins a CED registry if none currently has — CMS's approved-study list is updated on an ongoing basis, not on a fixed annual schedule.

How we know all this: this article's federal coverage rules come from Medicare.gov's own coverage page for monoclonal antibody treatment of early Alzheimer's disease, CMS's National Coverage Determination 200.3 and its April 2022 fact sheet, and CMS's July 2023 statement on broader Leqembi coverage. Pricing comes directly from Eisai Inc.'s product price list (effective July 13, 2026) and its January 2023 launch pricing statement, and from Eli Lilly and Company's own investor announcement of Kisunla's FDA approval. South Dakota prevalence data comes from the Alzheimer's Association. Compiled by a data desk built by Strategic AI Architects. This is education, not medical or legal advice; the decision to start treatment belongs to you and a licensed physician. Confirm your specific plan's coverage, prior authorization rules, and cost-sharing with a licensed agent, your plan directly, or Medicare.gov. We take no payment from any carrier or drug manufacturer to feature a plan or a drug, and Big Sioux Benefits does not offer every plan available in your area — see the disclosure in our footer.