Aetna · Imlifidase · US health-plan appeal rights

Imlifidase denied as not FDA-approved for this use by Aetna?

Q: How long do I have to appeal a Aetna Imlifidase denial?

Internal appeal window: Typically 180 days from the denial date. External review window: Typically 60–120 days after the final internal denial. The clock starts from the date on the denial letter.

Off-label use is widespread in medicine. If the literature and a recognised specialty-society guideline support the use, plans frequently approve on appeal — especially for cancer, cardiology, and rare disease.

By Michael John Ryan, Founder & Privacy Officer, DenialHelp, LLC

Last reviewed 2026-05-09

Policy data current as of 2026-04-26

US health-plan appeal rights

Cite: Most US health plans have appeal rights under either the ACA, ERISA, or Medicare/Medicaid rules

Most US health plans are required by federal law to give you both an internal appeal (where the insurer reconsiders) and an external review (where an independent reviewer decides). The exact timelines and processes depend on what kind of plan you have — marketplace / employer group, self-funded, Medicare Advantage, or Medicaid MCO — but in every case there's a window after the denial during which you have the right to fight it.

Internal appeal window

Typically 180 days from the denial date

External review window

Typically 60–120 days after the final internal denial

What Aetna typically requires

As of April 2026: imlifidase is NOT FDA-approved in US (BLA accepted Feb 2026, target action date pending). Aetna typically denies as 'investigational / not FDA-approved.' EMA conditional 2020 in EU.

Source policy: Aetna CPB on Imlifidase (Idefirix) for Desensitization in Highly Sensitized Kidney Transplant Candidates

What works in the appeal

Acknowledge US regulatory status (BLA accepted Feb 2026, FDA target action date pending). Pivotal data: Highdose-001/02 (Jordan AJT 2015) + ConfIdeS US Phase 3 met primary eGFR endpoint at 12 mo in cPRA ≥99.9% recipients. EMA conditional approval Aug 2020 — 2.5+ yrs of European real-world use. For US patient with emergent compatible deceased-donor offer in highly sensitized (cPRA ≥98%) candidate, request: (a) compassionate-use IND via FDA expanded access; OR (b) cover concurrent standard desensitization (rituximab + IVIG + TPE per Vo NEJM 2008 + Montgomery NEJM 2011) which IS standard of care; OR (c) UNOS Kidney Paired Donation Pilot Program enrollment. Document cPRA, DSA MFI, prior crossmatch failures, and waitlist time.

Next steps

Find the date on the denial letter — your appeal window starts there.
Read your plan's Summary of Benefits and Coverage (SBC) for the specific deadlines.
Request the insurer's claim file in writing — they must provide it.
Submit your appeal in writing with new clinical evidence and a physician statement.

Get the letter drafted

DenialHelp drafts your appeal in 5 minutes — $40 list price, $30 for your first letter (use code SEO25). We cite the federal regs and the specific clinical evidence your plan responds to. Your physician signs and sends.

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Related appeal guides

Other Aetna appeals

Other denial reasons for Aetna Imlifidase

denied as not medically necessary denied for failing step therapy denied as non-formulary denied for missing prior authorization denied as experimental or investigational

This guide describes general US federal appeal rights based on Most US health plans have appeal rights under either the ACA, ERISA, or Medicare/Medicaid rules. Your specific plan documents (Summary of Benefits and Coverage, Evidence of Coverage) override anything here. DenialHelp is not your lawyer and not your physician — we draft appeal letters that your physician signs. Outcomes depend on your insurer's decision and factors outside our control. Reviewed by Michael John Ryan on 2026-05-09. Editorial standards: denialhelp.com/authors.