Leqembi (Lecanemab) Denied by Insurance? How to Appeal

Leqembi (lecanemab), approved by the FDA in July 2023 as the first amyloid-targeting therapy to demonstrate statistically significant slowing of Alzheimer's disease progression, carries a list price of $26,500 per year — plus significant infusion costs. Coverage access has been contentious since launch. If your insurer or Medicare plan denied Leqembi, here is how to build an effective appeal.

Why Insurers Deny Leqembi Claims

Leqembi denials follow specific patterns tied to the strict clinical criteria required for appropriate use:

• Patient staging criteria not met — Leqembi is FDA-approved only for MCI (mild cognitive impairment) or mild dementia due to Alzheimer's disease; patients with moderate-to-severe Alzheimer's (CDR ≥2 or MMSE <20) are not appropriate candidates, and denial is clinically appropriate
• Amyloid confirmation not documented — A positive amyloid PET scan or CSF analysis (low Aβ42, elevated p-tau181) is required for the FDA approval; if this documentation is not in the PA submission, denial is routine
• Medicare Advantage plan adding requirements beyond the NCD — MA plans cannot be more restrictive than Medicare's National Coverage Determination for Leqembi; if your MA plan is imposing additional requirements, this is a challengeable position
• Private insurance criteria not aligned — Commercial insurers vary widely; some follow Medicare's NCD; others have restrictive or no coverage policies, particularly if they classified Leqembi as investigational before traditional FDA approval in July 2023
• Prior Authorization Denied: How to Appeal" class="auto-link">Prior authorization process errors — Incomplete documentation packages from the infusion center or neurologist's office — missing cognitive testing results, amyloid confirmation, or ARIA risk assessment — are common correctable causes of denial
• ARIA risk profile concerns — Patients with more than 4 microhemorrhages on baseline MRI have elevated ARIA risk; some plans require MRI baseline documentation before authorizing treatment

Under ACA §2719 and ERISA §1133, you have the right to a written denial explanation, internal appeal, and independent External Independent Review: Complete Guide" class="auto-link">external review.

How to Appeal a Leqembi Denial

Step 1: Confirm Complete Clinical Documentation Is Assembled

Have your neurologist provide the complete documentation package: cognitive testing results (MMSE, MoCA, CDR — confirming MCI or mild dementia, NOT moderate/severe AD), the amyloid confirmation (amyloid PET scan report with positive elevated amyloid or CSF analysis showing low Aβ42 with elevated p-tau181), baseline MRI documenting ARIA risk profile (specifically microhemorrhage count), and APOE ε4 genotyping if performed. Missing any element is the most common correctable cause of denial.

Step 2: Get Your Neurologist to Write a Comprehensive Letter of Medical Necessity

The letter should include your diagnosis (MCI or mild dementia — not moderate/severe), CDR score, MMSE score, amyloid PET or CSF results confirming amyloid pathology, ARIA baseline MRI findings, and a clear statement of why Leqembi specifically is the appropriate treatment. Cite the FDA traditional approval date (July 2023) and the CLARITY-AD Phase 3 trial results demonstrating 27% slowing of cognitive decline (CDR-SB) over 18 months — the first amyloid-targeting therapy to demonstrate statistically significant slowing of Alzheimer's progression in a Phase 3 trial.

Step 3: For Medicare Advantage Denials — Cite the CMS NCD Directly

If your Medicare Advantage plan is imposing requirements beyond the CMS National Coverage Determination, cite the NCD directly: after traditional FDA approval (July 2023), Medicare covers Leqembi for beneficiaries with MCI or mild dementia due to Alzheimer's with confirmed amyloid pathology. MA plans must cover what traditional Medicare covers. Escalate by calling 1-800-MEDICARE (1-800-633-4227) and requesting a Medicare Advantage grievance or formal appeal.

Step 4: For Commercial Insurance Denials — Argue Medical Necessity and Early Intervention Urgency

Your neurologist's letter should address why treatment at the current early stage is medically necessary: Leqembi is only appropriate for early Alzheimer's; once the disease progresses to moderate/severe, the treatment window closes permanently. Denying Leqembi to an early-stage patient denies the only available opportunity to slow progression. Also address cost-effectiveness: the downstream cost savings from delayed nursing home placement and reduced caregiver burden are meaningful.

Step 5: Request Expedited Review — Alzheimer's Progression Is Time-Sensitive

Request expedited internal review under ACA §2719. The treatment window for Leqembi is specifically the early stage of Alzheimer's disease. Document why delay would be medically harmful — specifically that further cognitive decline during a prolonged review process may disqualify the patient from the treatment window.

Step 6: Request External Review After an Internal Denial

Under ACA §2719, after an internal appeal denial you are entitled to independent external review. An external reviewer applying current FDA approval standards and AAN (American Academy of Neurology) position statements evaluates your case. The external decision is binding on the insurer.

What to Include in Your Appeal

• Insurance or Medicare denial letter with the specific reason and criteria identified
• Your member ID and claim number
• Cognitive testing results (MMSE, MoCA, CDR) confirming MCI or mild dementia stage
• Amyloid PET scan report (positive) OR CSF analysis (low Aβ42, elevated p-tau181)
• Baseline MRI brain report with ARIA microhemorrhage count
• Neurologist's letter of medical necessity citing FDA traditional approval (July 2023) and CLARITY-AD trial results
• For Medicare Advantage: CMS NCD language and MA plan requirements comparison

Fight Back With ClaimBack

Leqembi denials are among the most consequential — and most time-sensitive — insurance decisions facing Alzheimer's patients. A well-constructed appeal citing CLARITY-AD data, FDA approval status, and the narrow early-stage treatment window significantly increases your odds of approval before that window closes. ClaimBack generates a professional appeal letter in 3 minutes. Start your free claim analysis → Free analysis · No credit card required · Takes 3 minutes

Related Reading

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Internal vs External Insurance Appeal