Leqembi vs Kisunla access guide: anti-amyloid mAb coverage, amyloid confirmation, ARIA monitoring, registry enrollment, and payer documentation

Leqembi (lecanemab-irmb, Eisai/Biogen) and Kisunla (donanemab-azbt, Eli Lilly) are the only two FDA-approved disease-modifying therapies for early Alzheimer's disease. Both are anti-amyloid monoclonal antibodies administered by IV infusion. Leqembi received traditional FDA approval on July 6, 2023; Kisunla followed on July 2, 2024. In August 2025, the FDA approved a subcutaneous autoinjector maintenance formulation of Leqembi for patients who have completed at least 18 months of IV therapy.

This guide covers the practical differences between Leqembi and Kisunla for access teams: amyloid confirmation pathways, CMS Coverage with Evidence Development (CED) registry requirements, ARIA monitoring schedules, payer documentation, HCPCS coding, and reauthorization evidence.

Short answer

Amyloid confirmation before treatment

Both drugs require documented evidence of cerebral amyloid-beta pathology before initiation. Acceptable modalities:

1. Amyloid PET imaging: a positive amyloid PET scan (florbetapir, flutemetamol, florbetaben, or Pittsburgh compound-B) is the gold standard. CMS expanded Medicare coverage of amyloid PET to one scan per lifetime in October 2023; some commercial plans cover one scan for treatment qualification. HCPCS codes include A9586 (florbetapir), Q9982 (flutemetamol), and A9586/A9598 for other tracers.

2. CSF biomarkers: a positive CSF test showing decreased amyloid-beta 42 (or decreased Aβ42/Aβ40 ratio) with elevated phosphorylated tau meets the requirement for both drugs and for most payer policies.

3. Blood biomarkers: FDA-cleared plasma tests such as the Lumipulse pTau217/Aβ42 assay are emerging but carry caveats. The Lumipulse test was placed under a Class II recall in early 2026 due to false-positive concerns with specific manufacturing lots. Payers vary on whether plasma tests alone satisfy amyloid confirmation. Most require confirmatory PET or CSF if the blood test is borderline.

4. Documentation for PA: Include the imaging report, CSF lab results, or blood biomarker report with quantitative values and the interpreting physician's signature. UHC requires baseline documentation within 12 months prior to treatment initiation.

CMS Coverage with Evidence Development (CED)

Both Leqembi and Kisunla are covered under Medicare Part B through CMS's National Coverage Determination (NCD 200.3) with a Coverage with Evidence Development (CED) requirement:

• Registry enrollment: The prescribing physician must participate in a CMS-approved registry (the CMS-facilitated national registry, NCT 06058234, or another CMS-approved CED study). The registry collects minimal clinical data at treatment initiation and at follow-up intervals.
• Diagnosis codes: Claims must include both Z00.6 (encounter for examination for clinical research participation) and an appropriate AD diagnosis code (G30.0, G30.1, G30.8, G30.9, or G31.84 for MCI).
• Registry modifiers: Institutional claims must include modifier Q0 or Q1 to denote registry participation. Institutional claims on UB-04 forms require condition code 30 and type of bill 12X, 13X, or 85X.
• Clinical team requirement: CMS requires that the prescribing physician practices in an appropriate setting with a structured clinical team and follow-up care.
• Patient cost-sharing: Under original Medicare, patients pay 20% coinsurance on the Part B–allowed amount after meeting the deductible. Medigap or secondary coverage may offset this. Medicare Advantage plans may have different cost-sharing structures; patients should verify with their plan.

Commercial payer registry attestation

Commercial payers including Blue Cross Blue Shield of Massachusetts (Policy 946), UHC, Cigna, and Aetna require the prescriber to attest to CMS registry participation as a condition of covering Leqembi or Kisunla for their commercial members — even though the registry does not collect data from non-Medicare patients. This is a widespread policy alignment that access teams should anticipate.

APOE genotyping and ARIA risk counseling

Both drugs carry an FDA boxed warning for amyloid-related imaging abnormalities (ARIA), which can include brain edema (ARIA-E) and microhemorrhages (ARIA-H). APOE ε4 homozygotes are at significantly higher risk:

• APOE testing: Payers universally require that APOE ε4 genotyping be offered before treatment initiation. The test does not determine eligibility — it informs risk counseling. HCPCS code S3852 or CPT 81401 may be used.
• Counseling attestation: Most payer policies (UHC, BCBSMA, CarePartners CT) require provider attestation that the patient has been counseled about ARIA risk across genotypes and has shared in the decision to proceed.
• Anticoagulant restriction: Patients on therapeutic-dose anticoagulants are generally excluded. UHC specifically requires documentation that the patient is not on oral anticoagulants. Low-dose aspirin is typically acceptable.
• Baseline MRI: A brain MRI must be completed within 12 months (most plans) or 6 months (some plans) before starting treatment, and within 12 months is the standard.

ARIA monitoring schedules

The MRI monitoring schedules differ between the two drugs:

Leqembi

MRI before the 5th, 7th, and 14th infusions, then as clinically indicated. If ARIA is detected, follow the label's dosing interruption guidance and document radiographic resolution or stabilization before continuing.

Kisunla

MRI before the 2nd, 3rd, 4th, and 7th infusions — a more intensive early schedule reflecting higher observed ARIA rates in clinical trials. Additional MRIs as clinically indicated.

Reauthorization MRI evidence

For continuation of therapy, payers require documentation that follow-up MRIs demonstrate either resolution of ARIA or that ARIA severity is manageable. BCBSMA's Policy 946 specifies "radiographic resolution and/or stabilization." UHC requires prescriber attestation that continuation is appropriate based on ARIA severity and clinical symptoms.

Payer-specific coverage criteria

UnitedHealthcare

UHC covers Leqembi and Kisunla under its Commercial Medical Benefit Drug Policy (effective April 2026). Requirements include:

• Diagnosis of MCI or mild AD dementia with amyloid confirmation
• Prescribed by a neurologist, geriatric psychiatrist, or geriatrician who specializes in dementia
• MMSE score documented: Leqembi ≥ 22 and ≤ 30; Kisunla ≥ 20 and ≤ 28
• Clinical Dementia Rating (CDR) global score of 1 or less
• Stable doses of donepezil, rivastigmine, galantamine, and/or memantine for at least 12 weeks prior
• Not used in combination with other anti-amyloid mAbs
• Not progressed to moderate or severe AD
• Reauthorization every 12 months with continued CED registry participation and documented clinical stability

Blue Cross Blue Shield of Massachusetts

Policy 946 covers both drugs for commercial and Medicare members with similar criteria:

• CMS registry participation attestation required
• MMSE: Leqembi ≥ 22 to ≤ 30; Kisunla ≥ 20 to ≤ 28
• CDR global score ≤ 1
• Vitamin B12 within normal limits (to exclude reversible causes)
• No concurrent IVIG therapy
• Initial authorization for 12 months; reauthorization requires documented clinical improvement or stability

Horizon Blue Cross Blue Shield of New Jersey

Horizon's criteria mirror BCBSMA with specific additional requirements:

• Specialist (neurology, gerontology, or consultation) required
• Patient has not progressed to moderate or severe AD
• MMSE ranges identical to BCBSMA

UHC reauthorization criteria

UHC's continuation of therapy policy for Leqembi specifies cognitive assessment thresholds that must be met no earlier than 4 weeks prior to a reauthorization request:

• CDR global score of 0.5 or 1.0 (must not have progressed to ≥ 2.0)
• CDR Memory Box score of 0.5 or greater
• One of: MMSE ≥ 20, MoCA ≥ 17, or SLUMS ≥ 17
• Follow-up MRI completed after initiation; if ARIA observed, prescriber attests to radiographic resolution/stabilization
• Reauthorization for no more than 12 months

For Kisunla, UHC grants initial authorization for up to 6 months. Continuation requires documented follow-up MRI and ongoing CED registry participation.

Aetna

Aetna Clinical Policy Bulletin 1026 covers both lecanemab and donanemab. Aetna lists relevant HCPCS codes (J0174 for Leqembi, J0175 for Kisunla) and CPT codes for drug administration (96413, 96365) and molecular pathology (81401 for APOE, 81405 for PSEN1, 81406 for APP/PSEN2). The policy requires:

• Traditional FDA-approved indication met
• Amyloid confirmation
• APOE counseling attestation
• Baseline MRI within 12 months
• Not combined with other anti-amyloid mAbs
• Site of Care utilization management policy applies (may restrict infusion to specific settings)
• Prescriber specialties: geriatrician, neurologist, psychiatrist, or neuropsychiatrist

HCPCS billing

For Leqembi IV: bill J0174 at 10 mg/kg × patient weight in kg units. For Kisunla: bill J0175 at the mg dose administered divided by 2 (per 2 mg unit); 700 mg = 350 units, 1400 mg = 700 units.

Kisunla stopping rules and treatment duration

Kisunla has a unique treatment-duration feature: approximately 70% of patients in the TRAILBLAZER-ALZ 2 trial achieved amyloid plaque clearance by 18 months, at which point treatment can be discontinued. This contrasts with Leqembi, which is labeled for chronic therapy (every-2-week IV or weekly SC maintenance). The stopping-rule difference has payer cost implications:

• Payers may prefer Kisunla for patients likely to achieve plaque clearance because the total drug cost is lower (limited treatment duration vs chronic therapy).
• However, Kisunla's WAC is ~$32,000/year vs ~$26,000/year for Leqembi, so patients who do not achieve clearance and remain on Kisunla long-term incur higher annual costs.
• Access teams should document the treatment-duration discussion in the PA submission, including the rationale for drug selection.

Patient support programs

Leqembi Companion (Eisai)

• LEQEMBI Companion provides benefit verification, prior authorization support, and financial assistance navigation.
• For commercially insured patients, copay assistance may be available. Medicare/Medicaid patients are directed to the Eisai Patient Assistance Program for eligible uninsured or underinsured patients.
• Website: eisaipatientsupport.com/hcp/leqembi
• Phone: 1-833-453-7362

Kisunla Support (Eli Lilly)

• Lilly Support provides benefit investigation, PA assistance, and refill coordination.
• Copay assistance for commercially insured patients; patient assistance for eligible uninsured patients.
• Website: kisunla.lilly.com
• Phone: 1-844-723-5485

Key documentation checklist for PA submission

1. Amyloid confirmation report (PET, CSF, or validated blood biomarker)
2. APOE ε4 genotyping results (or documentation that testing was offered and patient declined/accepted)
3. Baseline brain MRI within 12 months
4. MMSE score within qualifying range (Leqembi ≥ 22, Kisunla ≥ 20)
5. CDR global score documentation (≤ 1)
6. Diagnosis of MCI or mild AD dementia (ICD-10: G30.x or G31.84)
7. Stable dose of cholinesterase inhibitor and/or memantine for ≥ 12 weeks (if applicable)
8. Prescriber specialty: neurologist, geriatric psychiatrist, or geriatrician
9. CMS CED registry enrollment confirmation
10. Anticoagulant status (not on therapeutic-dose anticoagulation)
11. Attestation that patient has not progressed to moderate/severe AD

Sources

• CMS. Statement: Broader Medicare Coverage of Leqembi Available Following FDA Traditional Approval. July 2023. https://www.cms.gov/newsroom/press-releases/statement-broader-medicare-coverage-leqembi-available-following-fda-traditional-approval
• Alzheimer's Association. CMS Treatment Coverage Policy. https://www.alz.org/alzheimers-dementia/treatments/cms-medicare-coverage
• Eli Lilly. Kisunla Billing and Coding Guide. https://kisunla.lilly.com/assets/pdf/billingandcodingguide.pdf
• Eisai. LEQEMBI Coding Quick Reference Guide. https://www.eisaipatientsupport.com/-/media/Files/PatientSupport/Coding-Quick-Ref-Guide.pdf
• FDA. Leqembi (lecanemab-irmb) Approval Letter. July 2023. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2023/761178Orig1s018Approv.pdf
• UnitedHealthcare. Leqembi Commercial Medical Benefit Drug Policy. Effective April 2026. https://www.uhcprovider.com/content/dam/provider/docs/public/policies/comm-medical-drug/leqembi.pdf
• Blue Cross Blue Shield of Massachusetts. Monoclonal Antibodies for Treatment of Alzheimer's Disease, Policy 946. https://www.bluecrossma.org/medical-policies/sites/g/files/csphws2091/files/acquiadam-assets/946%20Monoclonal%20Antibodies%20for%20Treatment%20of%20Alzheimer%27s%20Disease.pdf
• Aetna. Lecanemab-irmb (Leqembi) Clinical Policy Bulletin 1026. https://www.aetna.com/cpb/medical/data/1000_1099/1026.html
• Horizon Blue Cross Blue Shield of New Jersey. Amyloid Beta-Directed Antibodies Benefit Criteria. https://www.horizonblue.com/providers/products-programs/pharmacy/self-insured-customized-pharmacy-coverage/amyloid-beta-directed-antibodies
• CarePartners of Connecticut. Leqembi Medical Necessity Guideline. https://www.carepartnersct.com/cpct-pdoc-leqembi
• BrightFocus Foundation. Leqembi and Kisunla: Your Questions Answered. https://www.brightfocus.org/resource/leqembi-and-kisunla-your-questions-answered