By Counterforce Health Team in Enhertu (fam-trastuzumab deruxtecan-nxki) —

How to Get Enhertu (Fam-Trastuzumab Deruxtecan-nxki) Covered by Aetna in Michigan: Appeals Guide, Forms & Timelines

Quick Answer: If Aetna denied Enhertu (fam-trastuzumab deruxtecan-nxki), you have strong appeal rights in Michigan. Start with Aetna's internal appeal within 60 days, then file for Michigan DIFS external review within 127 days if denied. Key requirements: documented HER2 testing, prior therapy failures, and medical necessity letter citing FDA approval and clinical guidelines. Submit appeals via Aetna's provider portal or call 1-888-632-3862.

Table of Contents

Understanding Aetna's Enhertu Coverage Requirements

Enhertu requires prior authorization from Aetna for all FDA-approved indications. The drug is covered under your medical benefit (not specialty pharmacy) since it's administered by IV infusion in clinical settings.

Coverage at a Glance

Requirement What It Means Where to Find It
Prior Authorization Required for all indications Aetna 2025 Precertification List
HER2 Testing Must confirm HER2-positive, HER2-mutant, or HER2-low status Aetna Clinical Policy Bulletin #966
Prior Therapy Evidence of failed standard treatments Aetna Clinical Policy Bulletin #966
Site of Care Outpatient infusion center preferred over hospital Aetna Clinical Policy Bulletin #966
Appeals Deadline 60 days for internal, 127 days for Michigan external Michigan DIFS External Review

Aetna's specific criteria include:

  • Breast Cancer: HER2-positive recurrent/metastatic disease after prior HER2-targeted therapy
  • Lung Cancer: HER2-mutant NSCLC after prior systemic therapy
  • Gastric Cancer: HER2-positive locally advanced/metastatic after trastuzumab-based regimen

Reading Your Denial Letter

Your Aetna denial letter contains critical information for your appeal. Look for:

  1. Denial reason code - Often "not medically necessary," "experimental," or "step therapy required"
  2. Appeal deadline - Usually 60 days from the denial date
  3. Required documentation - What Aetna wants to see in your appeal
  4. Benefit type - Confirm it's under medical benefit, not pharmacy
Tip: If the denial cites "investigational" or "experimental," this is often overturned when you provide FDA approval documentation and clinical guidelines supporting Enhertu for your specific cancer type.

Step-by-Step: Fastest Path to Approval

1. Gather Essential Documentation

Who: Patient and clinic staff
Timeline: 1-2 days

  • Insurance card and policy details
  • HER2 testing pathology report with results
  • Complete prior therapy history (drugs, dates, outcomes)
  • Clinic notes documenting disease progression or treatment failure
  • Original denial letter

2. Submit Prior Authorization Request

Who: Prescribing oncologist
Timeline: 2-3 weeks for standard review
Submit via: Aetna provider portal or call 1-888-632-3862

Include:

  • Completed PA form with ICD-10 diagnosis codes
  • HER2 testing results
  • Documentation of prior therapy failures
  • Medical necessity letter (see template below)

3. Request Peer-to-Peer Review (If Initially Denied)

Who: Oncologist
Timeline: Usually scheduled within 72 hours
Call Aetna at 1-888-632-3862 to request a peer-to-peer discussion with their medical director.

4. File Internal Appeal

Who: Patient or provider
Deadline: 60 days from denial date
Submit to: Aetna Appeals Department via provider portal or mail

5. File Michigan External Review (If Internal Appeal Fails)

Who: Patient
Deadline: 127 days from final Aetna denial
Submit to: Michigan DIFS External Review

Medical Necessity Letter Template

Here's a framework your oncologist can customize:

RE: Medical Necessity Appeal for Enhertu (fam-trastuzumab deruxtecan-nxki)

Dear Aetna Medical Director,

I am requesting coverage approval for Enhertu for my patient [Name], DOB [Date], Policy #[Number], who has [specific diagnosis with ICD-10 code].

Clinical Rationale:

  • HER2 Status: Patient tested HER2-[positive/mutant/low] via [IHC/FISH] on [date] (report attached)
  • Prior Therapies: Patient has failed/progressed on:
    • [List specific drugs, dates, duration, reason for discontinuation]
  • FDA Indication: Enhertu is FDA-approved for [patient's specific indication]
  • Guideline Support: [NCCN/ASCO] guidelines recommend Enhertu for this clinical scenario

Supporting Evidence:

  • Pathology report confirming HER2 status
  • Imaging showing disease progression on prior therapy
  • Clinical notes documenting treatment failures

Risk Mitigation: Patient will be monitored per FDA labeling for interstitial lung disease with regular clinical assessments and imaging as indicated.

Given the FDA approval, clinical guideline support, and this patient's documented treatment history, Enhertu represents standard-of-care therapy. Delay in treatment may result in disease progression and increased morbidity.

Sincerely, [Physician name, credentials, NPI]

Aetna Appeals Process in Michigan

Internal Appeal Process

Level Timeline How to Submit Required Documents
First-Level 30 days for standard, 72 hours for urgent Provider portal or 1-888-632-3862 Medical records, denial letter, PA form
Second-Level 30 days for standard Same as first-level All first-level docs plus additional clinical evidence

Urgent/Expedited Appeals: Available when delay would seriously jeopardize health. Requires physician certification of urgency.

Required Documentation for Appeals:

  • Complete medical records supporting diagnosis
  • HER2 testing results
  • Documentation of prior therapy failures
  • Clinical guidelines supporting Enhertu use
  • Physician attestation of medical necessity

Michigan External Review Process

If Aetna's internal appeals fail, Michigan offers robust external review rights through the Department of Insurance and Financial Services (DIFS).

Key Timelines:

  • File deadline: 127 days from final Aetna denial
  • Standard decision: Within 60 days
  • Expedited decision: Within 72 hours (requires physician urgency letter)

How to File:

  1. Complete DIFS External Review Form
  2. Include all medical records and Aetna correspondence
  3. Submit online, by mail, or fax to DIFS

Contact DIFS:

  • Phone: 877-999-6442 (Monday-Friday, 8 AM-5 PM)
  • Mail: Department of Insurance and Financial Services, Office of Appeals, P.O. Box 30220, Lansing, MI 48909-7720
Michigan Advantage: DIFS external reviews are binding on insurers. If the independent medical experts rule in your favor, Aetna must cover the treatment.

Common Denial Reasons & How to Fix Them

Denial Reason How to Overturn Key Documents Needed
"Not medically necessary" Cite FDA approval + clinical guidelines FDA label, NCCN guidelines, medical necessity letter
"Experimental/investigational" Provide FDA approval documentation FDA approval letter, clinical studies
"Step therapy not met" Document prior therapy failures Treatment timeline, progression notes, imaging
"Non-formulary" Request formulary exception Medical necessity letter, alternative drug contraindications
Missing HER2 testing Provide biomarker results Pathology report with HER2 status

Cost Assistance Options

While appealing, explore these cost-saving programs:

Manufacturer Support:

Foundation Grants:

  • Patient Access Network Foundation
  • CancerCare Co-Payment Assistance Foundation
  • Good Days (formerly Patient Services Inc.)

State Programs:

  • Michigan Medicaid may cover Enhertu for eligible patients
  • Check eligibility for Michigan's Healthy Michigan Plan

At Counterforce Health, we help patients and clinicians turn insurance denials into successful appeals by creating targeted, evidence-backed letters that address each payer's specific requirements. Our platform analyzes denial letters and drafts point-by-point rebuttals using the right clinical evidence and procedural requirements.

FAQ

How long does Aetna prior authorization take in Michigan? Standard PA decisions typically take 14-30 days. Expedited requests (when delay would harm the patient) are decided within 72 hours.

What if Enhertu is non-formulary on my Aetna plan? You can request a formulary exception by demonstrating medical necessity and showing that formulary alternatives are inappropriate or have failed.

Can I request an expedited appeal? Yes, if your physician certifies that delay would seriously jeopardize your health or ability to regain maximum function. Both Aetna and Michigan DIFS offer expedited review processes.

Does step therapy apply if I've tried similar drugs outside Michigan? Yes, document all prior therapies regardless of where you received them. Aetna should accept out-of-state treatment history as evidence of step therapy completion.

What happens if both internal and external appeals fail? You may have additional options including seeking care at a different facility, exploring clinical trials, or working with Counterforce Health to identify alternative approval strategies.

How much does Enhertu cost without insurance? Enhertu costs approximately $2,440 per 100mg vial, with total cycle costs varying based on patient weight and dosing. Most patients require multiple vials per treatment cycle.

Can I get Enhertu through home infusion? Enhertu requires IV administration in a medical setting due to its complexity and monitoring requirements. Home infusion is generally not available for this medication.

What should I do while my appeal is pending? Continue working with your oncology team on alternative treatments if appropriate. Don't delay other necessary care while waiting for the appeal decision.

Sources & Further Reading

Disclaimer: This information is for educational purposes only and does not constitute medical or legal advice. Insurance coverage decisions depend on individual policy terms and medical circumstances. Always consult with your healthcare provider and insurance company for guidance specific to your situation. For additional help with insurance appeals in Michigan, contact Michigan DIFS at 877-999-6442.

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