Amondys 45 (casimersen) — Medical-benefit coverage and prior authorization for Duchenne muscular dystrophy (exon 45 skipping)
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Policy governing medical-benefit coverage and prior authorization requirements for intravenous Amondys 45 (casimersen) for members with Duchenne muscular dystrophy whose genetics are amenable to exon 45 skipping.
No material clinical or coverage changes in this revision.
Coverage Criteria for Amondys 45 (casimersen)
Initial Therapy
Covered when ALL of the following are met
Documented diagnosis per FDA indication.
Must be documented in the medical record.
Stable dose must be noted in clinical documentation or reason for avoidance provided.
Baseline kidney function (e.g., serum creatinine, eGFR) must be in the record before initiation.
Concurrent exon skipping therapies are excluded.
Concurrent treatment with another exon skipping therapy for Duchenne muscular dystrophy is excluded. Members receiving Amondys 45 must not be treated at the same time with any other exon skipping agent for DMD; concurrent use will not meet coverage criteria.
Use of Amondys 45 is not supported for patients who do not have documentation of a confirmed DMD gene mutation amenable to exon 45 skipping. Coverage also requires documentation of a stable dose of corticosteroids prior to starting therapy or a documented reason for not being on corticosteroids, and kidney function testing prior to initiation. Requests lacking these required documents or genetic confirmation will be considered not medically necessary.
Initial Authorization Requirements
Initial Authorization
Initial authorization requires documentation of:
Per FDA-approved indication.
Genetic test report must be provided.
Stability of dose or reason for avoidance should be recorded in clinical notes.
Include relevant laboratory results in the authorization request.
Concurrent treatment with another exon skipping agent is not permitted.
Provider Actions, Documentation & Denial Triggers
Prior authorization required; use CPT infusion administration codes
Prior authorization is required for administration of Amondys 45 under the member's medical benefit (buy-and-bill). For IV infusion billing reference, the policy lists chemotherapy administration CPT codes 96413 (up to 1 hour, single or initial substance/drug) and 96415 (each additional hour).
No step therapy required
The policy specifies no step therapy requirements for Amondys 45; there are no prerequisite treatments or failure trials required prior to authorization.
Submit genetic, corticosteroid, and kidney function documentation
Required documentation for initial authorization must include genetic testing confirming the patient's DMD gene mutation is amenable to exon 45 skipping, documentation of a stable corticosteroid dose prior to starting therapy or a documented reason for not being on corticosteroids, and kidney function testing prior to initiation.
- Genetic test confirming DMD mutation amenable to exon 45 skipping.
- Documentation of stable corticosteroid dose prior to therapy or documented reason for not using corticosteroids.
- Baseline kidney function testing prior to starting therapy.
Denial triggers: missing or non‑meeting documentation and concurrent exon skipping therapy
Coverage may be denied if required documentation is missing or criteria are not met — specifically if genetic testing does not confirm a DMD mutation amenable to exon 45 skipping, if corticosteroid status (stable dose or reason for not using) is not documented, if baseline kidney function testing is not provided, or if the patient is concurrently treated with another exon skipping therapy.
- No confirmed DMD mutation amenable to exon 45 skipping documented.
- No documentation of stable corticosteroid dose or valid reason for not being on corticosteroids.
- No baseline kidney function testing prior to initiation.
- Concurrent treatment with another exon skipping therapy for DMD.
Administration & Billing Codes
Administration Setting
Administer IV in provider setting (buy-and-bill); bill CPT 96413/96415
Amondys 45 is administered by intravenous infusion in a provider setting under the member's medical benefit via buy-and-bill; bill IV administration using the referenced CPT infusion administration codes (96413, 96415) as appropriate.
Key Definitions
Background
Amondys 45 (casimersen) is an antisense oligonucleotide indicated for treatment of Duchenne muscular dystrophy in patients with a confirmed DMD gene mutation amenable to exon 45 skipping. Approval is for intravenous administration under the medical benefit; coverage is contingent on genetic confirmation of exon 45 amenability, documentation of corticosteroid status (a stable dose prior to therapy or a documented reason for not using corticosteroids), baseline kidney function testing prior to starting therapy, and that the patient is not concurrently receiving another exon skipping therapy for DMD.
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