CurrentUnitedHealthcarePolicy IEXD00105.10

Amondys 45 (Casimersen) — Medical Benefit Drug Policy (Individual Exchange)

Medical benefit drug policy governing coverage criteria for Amondys 45 (casimersen) for treatment of Duchenne muscular dystrophy for UnitedHealthcare Individual Exchange plans (excludes MA, NV, NY).

Policy Summary

PayerUnitedHealthcare

PolicyAmondys 45 (Casimersen) — Medical Benefit Drug Policy (Individual Exchange)

Policy CodePolicy IEXD00105.10

Change TypeRevised coverage criteria (material)

Effective DateJul 1, 2025

Next Review Date

Key ActionObtain prior authorization and submit medical records confirming DMD with exon 45–amenable mutation and, if prior gene therapy, documentation of clinically meaningful functional decline.

SourceLink

POLICY UPDATE CHANGES

Revised coverage criteria for initial therapy to add a requirement addressing prior gene therapy exposure and documenting clinically meaningful functional decline since gene therapy.

12 monthsInitial authorization duration

12 monthsReauthorization duration

J1426HCPCS code

≥300 m6MWT threshold

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Coverage Criteria for Amondys 45 (casimersen)

Initial Therapy

Covered when ALL of the following are met

Initial Therapy - overall: Patient meets all listed requirements for initial therapy

Diagnosis and mutation: Diagnosis of Duchenne muscular dystrophy by, or in consultation with, a neurologist with expertise in the diagnosis of DMD; and submission of medical records confirming the DMD gene mutation is amenable to exon 45 skipping

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Baseline ambulatory function options: Either (A) submission of medical records confirming 6-Minute Walk Test (6MWT) ≥ 300 meters while walking independently prior to starting therapy, OR (B) ambulatory without assistive device AND (NSAA > 17 OR time to rise < 7 seconds)6MWT ≥ 300 m; NSAA > 17; TTR < 7 s

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Prior gene therapy: Either patient has not previously received gene therapy (e.g., Elevidys) for DMD, OR patient previously received gene therapy AND submission of medical records documenting a clinically meaningful functional decline since gene replacement therapy

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Concomitant therapy and prescribing: Amondys 45 is not used concomitantly with other exon skipping therapies for DMD; prescribed by, or in consultation with, a neurologist with expertise in the treatment of DMD; dosing per FDA-approved labeling

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Authorization length: Initial authorization will be for no more than 12 months12 months

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Continuation Therapy

Covered when ALL of the following are met

Continuation Therapy - overall: Patient meets all listed requirements for continuation/reauthorization

Ambulatory status: Submission of medical records confirming the patient is ambulatory without needing an assistive device

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Authorization length: Reauthorization will be for no more than 12 months12 months

Unproven

Unproven indications: Amondys 45 is unproven and not medically necessary for the treatment of other forms of muscular dystrophy (e.g., Becker muscular dystrophy)

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Amondys 45 (casimersen) is unproven and not medically necessary for the treatment of other forms of muscular dystrophy, such as Becker muscular dystrophy. Coverage is limited to indications and patient populations specifically supported by the policy criteria.

Use of Amondys 45 for Duchenne muscular dystrophy cases that are not amenable to exon 45 skipping, or for other muscular dystrophies (e.g., Becker muscular dystrophy), is considered not medically necessary (NMN) and is excluded from coverage.

Billing and Diagnostic Codes

HCPCS CodeHCPCS

J1426

Injection, casimersen, 10 mg

Diagnosis CodeICD-10

G71.01

Duchenne or Becker muscular dystrophy

6-Minute Walk Test (threshold)

6-Minute Walk Test threshold6MWT ≥ 300 meters (minimum baseline distance required for some initial therapy candidates)

Context of useApplies to ambulatory patients walking independently prior to starting Amondys 45 (no side-by-side assist, cane, walker, wheelchair, etc.)

Alternative baseline criteriaIf 6MWT not used, patient may qualify if ambulatory without assistive device AND (NSAA > 17 OR time to rise < 7 seconds)

Supporting clinical trial criteriaESSENCE trial enrollment included ambulatory patients with mean 6MWT ≥ 300 m and ≤ 450 m, supporting the clinical relevance of the 300 m threshold

Provider Requirements and Authorization

Prior Authorization

Prior Authorization Required

Prior authorization is required for Amondys 45 (casimersen). Initial authorization will be for up to 12 months. Reauthorization (continuation) requests are also required and, when approved, will be for up to 12 months.

Initial authorization: up to 12 months
Reauthorization/Continuation: up to 12 months

Prior Authorization

Concomitant Therapy Restriction

Amondys 45 must not be used concomitantly with other exon skipping therapies for DMD.

Examples: Exondys 51 (eteplirsen), Viltepso (viltolarsen), Vyondys 53 (golodirsen)

Documentation Required

Definitions and Molecular Eligibility

Mutation amenable to exon 45 skipping — definition

DefinitionMutation of the DMD gene that allows casimersen to bind exon 45 of dystrophin pre-mRNA and induce exon skipping to restore the reading frame.

FDA indication languageCasimersen is indicated for DMD patients who have a confirmed mutation of the DMD gene that is amenable to exon 45 skipping.

MechanismCasimersen binds to exon 45 of dystrophin pre-mRNA and induces splicing of the mutated exon to allow production of functional (truncated) dystrophin protein.

Documentation requiredMedical records must confirm the DMD gene mutation is amenable to exon 45 skipping for coverage consideration.

Background

Duchenne muscular dystrophy (DMD) is an X-linked recessive, degenerative neuromuscular disease caused by mutations in the dystrophin gene that lead to progressive muscle degeneration with cardiac and respiratory complications and early disability. Casimersen is an antisense oligonucleotide designed to bind exon 45 of dystrophin pre-mRNA and induce exon skipping to restore the dystrophin reading frame, increasing dystrophin production as measured in biopsy. Coverage of Amondys 45 under this policy is limited to patients with a confirmed DMD mutation that is amenable to exon 45 skipping and who meet the specific clinical and functional criteria described in the coverage sections.