CurrentAnthemPolicy CC-0189

Amondys 45 (casimersen) — Coverage Criteria

Clinical coverage criteria for Amondys 45 (casimersen) for treatment of Duchenne muscular dystrophy in members with mutations amenable to exon 45 skipping; governs prior authorization, continuation, quantity limits, and coding for Anthem members.

Policy Summary

PayerAnthem

PolicyAmondys 45 (casimersen) — Coverage Criteria

Policy CodePolicy CC-0189

Change TypeRoutine review — no material changes

Effective Date

Next Review DateAug 15, 2025

Key ActionObtain prior authorization and provide documentation of DMD diagnosis, genetic testing confirming an exon 45–amenable mutation, age, stable corticosteroid dose, 6MWT result, and FVC % predicted.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

30 mg/kgdosing / quantity limit

7–13 yrsage range

300–450 m6MWT requirement

≥50% predFVC requirement

J1426billing code

Coverage Criteria for Amondys 45 (casimersen)

Initial Therapy

Initial requests may be approved when ALL of the following are met:

Initial Approval Criteria: I. Individual has a diagnosis of Duchenne muscular dystrophy (DMD); AND II. Documentation is provided that individual has a genetic mutation that is amenable to exon 45 skipping; AND III. Individual is age 7-13 years; AND IV. Individual has been on a stable dose of oral corticosteroids; AND V. Documentation is provided that individual has a 6MWT ≥ 300 meters and < 450 meters; AND VI. Documentation is provided that individual has stable pulmonary function with FVC ≥ 50% predicted.

Based on inclusion parameters of NCT02500381.

Continuation Therapy

Continuation of therapy may be approved when ALL of the following are met:

Continuation Criteria: I. Criteria above were met at initiation of therapy; AND II. Documentation is provided that individual remains ambulatory (with or without an assistive device).

Ambulatory status required for ongoing therapy.

Policy Summary

PayerAnthem

PolicyAmondys 45 (casimersen) — Coverage Criteria

Policy CodePolicy CC-0189

Change TypeRoutine review — no material changes

Effective Date

Next Review DateAug 15, 2025

SourceLink

On This Page

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Not Medically Necessary / Exclusions

Amondys 45 may not be approved for the following:

Not Approved: I. Individual is using another exon skipping agent for DMD (including but not limited to Exondys 51, Vyondys 53); OR II. When the above criteria are not met and for all other indications.

Concurrent exon skipping agents excluded.

Concurrent administration of Amondys 45 with another exon skipping agent for Duchenne muscular dystrophy is excluded. Specifically, therapy will not be approved for individuals who are using another exon skipping agent for DMD (including but not limited to Exondys 51 or Vyondys 53).

Requests that do not meet the stated initiation or continuation criteria are not approved. In addition, Amondys 45 is not approved for indications other than DMD with a mutation amenable to exon 45 skipping. Coverage requires that all initiation criteria be met (diagnosis of DMD; genetic confirmation of an exon 45–amenable mutation; age 7–13 years; stable oral corticosteroid dose; 6MWT ≥ 300 meters and < 450 meters; and FVC ≥ 50% predicted) and that continuation criteria (met initiation criteria and documented ongoing ambulatory status) are satisfied.

Coding and Clinical Thresholds

HCPCSHCPCSCovered

J1426

Injection, casimersen, 10 mg [Amondys 45]

ICD-10 DiagnosisICD-10

G71.01

Duchenne or Becker muscular dystrophy

inv-08: 6-Minute Walk Test (6MWT) — clinical threshold for initiation/continuation (>=300 m and <450 m)

6MWT thresholdDocumentation of a 6-minute walk test (6MWT) result ≥ 300 meters and < 450 meters is required for initiation.

Use at initiationMust be met as part of initial approval criteria (NCT02500381 inclusion parameter).

Continuation relevanceAmbulatory status must be documented for continuation; initial 6MWT requirement remains part of the initiation baseline.

inv-09: Forced Vital Capacity (FVC) — pulmonary function threshold (>= 50% predicted)

FVC thresholdDocumentation of forced vital capacity (FVC) ≥ 50% predicted is required for initiation.

Source trial criteriaStable pulmonary function defined as FVC ≥ 50% predicted per NCT02500381 inclusion criteria.

Continuation noteStable pulmonary function established at initiation supports ongoing therapy; monitor per clinical judgment.

Provider Requirements, Prior Authorization, and Billing

Prior Authorization

Prior Authorization Required

Prior Authorization Required: Prior authorization is required for Amondys 45 (casimersen). Initial approval may be granted when ALL of the following are documented: diagnosis of Duchenne muscular dystrophy (DMD); genetic testing confirming an exon 45 amenable mutation; patient age 7-13 years; patient on a stable dose of oral corticosteroids; baseline 6-minute walk test (6MWT) ≥ 300 and < 450 meters; and baseline forced vital capacity (FVC) ≥ 50% predicted.

Initial approval criteria: diagnosis of DMD; exon 45 amenable mutation; age 7-13 years; stable oral corticosteroids; 6MWT ≥300 and <450 meters; FVC ≥50% predicted.

Step Therapy

Step Therapy / Sequencing

Step therapy / Sequencing: No step therapy is specified. Concurrent use of other exon-skipping agents for DMD (including but not limited to Exondys 51, Vyondys 53) is a contraindication to approval and will lead to denial of Amondys 45.

No prior step agents required.
Concurrent exon skipping agents (e.g., Exondys 51, Vyondys 53) — not allowed.

Documentation Required

Required Documentation

Required Documentation: Submit documentation supporting the initial or continuation criteria, including: clinical diagnosis of DMD; genetic test results confirming an exon 45–amenable mutation; patient age; documentation of stable oral corticosteroid regimen at initiation; baseline 6MWT and FVC values; and for continuation, documentation that the patient remains ambulatory. Prior to initiation, provide baseline laboratory monitoring per product guidance (serum cystatin C, urine dipstick, urine protein-to-creatinine ratio).

Diagnosis and genetic testing confirming exon 45 amenable mutation.
Age and evidence of stable corticosteroid use.
Baseline 6MWT (≥300 and <450 meters) and baseline FVC (≥50% predicted).
For continuation: documentation of ongoing ambulatory status.
Baseline labs prior to initiation: serum cystatin C, urine dipstick, urine protein-to-creatinine ratio.

Denial Risk

Quantity Limit / Denial Triggers

Quantity Limit and Denial Triggers: Dosing is limited to 30 mg/kg administered once weekly. Requests may be denied if dosing exceeds the quantity limit, if required clinical criteria or documentation are not met, or if the member is concurrently receiving another exon-skipping therapy.

Quantity limit: 30 mg/kg once weekly.
Denial triggers: concurrent use of other exon skipping agents; missing or not meeting initial/continuation criteria; dosing beyond the quantity limit.

Background

Duchenne muscular dystrophy (DMD) is a progressive, X‑linked genetic disorder caused by absence or deficiency of dystrophin, leading to muscle degeneration and loss of ambulation over time. Exon skipping with agents such as casimersen (Amondys 45) targets specific DMD gene mutations by causing the cellular splicing machinery to skip exon 45, which can restore the dystrophin reading frame and enable production of a shorter, partially functional dystrophin protein. Amondys 45 received accelerated approval based on increased dystrophin production in patients with mutations amenable to exon 45 skipping.

Definitions

inv-15: Amenable to exon 45 skipping — Definition describing genetic mutations amenable to exon 45 skipping

DefinitionA genetic deletion or mutation in the DMD gene for which exon 45 skipping would restore the dystrophin reading frame and allow production of a shorter, partially functional dystrophin protein.

Clinical intentExon 45 skipping is intended to convert an out-of-frame mutation to an in-frame transcript to enable dystrophin production.

Documentary requirementDocumentation of a genetic mutation amenable to exon 45 skipping is required for initiation of Amondys 45.