Casimersen (Amondys 45) coverage
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Medical necessity and prior authorization criteria for use of casimersen (Amondys 45) for Duchenne muscular dystrophy in Peach State Health Plan Medicaid members.
Six-minute walk test (6MWT) criterion changed from 300 meters to 180 meters to align with Department of Community Health request.
Criterion added that member has not previously received gene replacement therapy for DMD (e.g., Elevidys).
Agamree (vamorolone) added to list of oral corticosteroid options in Appendix B and initial criteria.
Appendix C updated with new contraindication per prescribing information.
Coverage Criteria for Casimersen (Amondys 45)
Initial Therapy
Covered when ALL of the following are met for initial approval:
See Appendix D for example mutations
Prior authorization is required for Emflaza and Agamree
Continuation Therapy
Covered when ALL of the following are met for continued therapy:
Not Covered Indications
Not authorized diagnoses/indications:
Contraindication: Serious hypersensitivity to casimersen or any of the inactive ingredients in Amondys 45 is a contraindication to use.
Coverage is governed by the member's plan documents and applicable law. This clinical policy is a guide to medical necessity and coverage is subject to all terms, conditions, exclusions and limitations of the member's coverage documents (e.g., evidence of coverage, certificate of coverage, policy, contract) and to state and federal requirements.
Use of casimersen for diagnoses or indications not specifically listed in the policy is not authorized. For requests where the diagnosis is not listed, refer to the applicable off-label use policy for the line of business (CP.CPA.09 for commercial, HIM.PA.154 for the Health Insurance Marketplace, and CP.PMN.53 for Medicaid) and follow plan administrative procedures.
Coding and Clinical Thresholds
| C9075 | Injection, casimersen, 10 mg |
Provider Actions and Authorization Requirements
Prior authorization required; billing code C9075
Prior authorization is required for Amondys 45 (casimersen). Use HCPCS code C9075 (Injection, casimersen, 10 mg) when billing.
- Prior authorization required for Amondys 45.
- Billing code: C9075 — Injection, casimersen, 10 mg.
Prior authorization for Emflaza and Agamree
Prior authorization is required for the listed oral corticosteroids when applicable (Emflaza and Agamree).
- Prior authorization required for Emflaza and Agamree as noted in initial criteria.
Use policy as guide to medical necessity for prior authorization
This clinical policy is a guide to medical necessity and is used to assist in making coverage decisions and administering benefits; prior authorization requirements are governed by the Health Plan's administrative procedures and member coverage documents.
- Policy serves as guide to medical necessity for coverage decisions and benefit administration.
- Prior authorization requirements follow Health Plan administrative procedures and member coverage documents.
No step-therapy specified for casimersen
No step-therapy sequence is defined for casimersen in this document.
- No prior step-therapy required before initiating casimersen; corticosteroid therapy is required concurrently or prior as specified.
Follow specific approval criteria when requesting authorization
Providers must ensure prescriptions and authorization requests follow the policy’s specific approval criteria (diagnosis, genetic confirmation, age, neurologist involvement, baseline assessments, corticosteroid use, absence of concurrent exon-skipping or prior gene therapy, and dose limits).
- Verify genetic testing confirming mutation amenable to exon 45 skipping.
- Confirm age ≤13 at therapy initiation and neurologist involvement.
- Ensure baseline 6MWT, LVEF, and FVC meet thresholds and dose ≤30 mg/kg/week.
Required documentation: office notes, labs, genetic testing
Submit supporting clinical documentation such as office chart notes, lab results, and genetic testing to demonstrate the member meets all approval criteria.
- Include genetic test confirming exon 45–amenable mutation.
- Provide recent (within required timeframes) 6MWT, LVEF, and FVC results and corticosteroid treatment history.
Follow coverage documents and Health Plan administrative policies
Providers must follow the member's coverage documents (evidence of coverage, certificate of coverage, policy, contract) and applicable Health Plan administrative policies when requesting coverage.
- Coverage requests are subject to terms, conditions, exclusions and limitations of the member's coverage documents.
- Follow Health Plan-level administrative policies and procedures.
Risk of denial if required documentation or criteria are missing; medical director review possible
Requests lacking required documentation (office notes, labs, genetic testing) or requests that do not meet the listed criteria may be denied; all requests may require medical director review.
- Insufficient documentation may result in denial.
- All requests may be subject to medical director review.
Coverage subject to coverage documents, exclusions, and legal requirements
Coverage decisions and the administration of benefits are subject to the terms, conditions, exclusions and limitations of the coverage documents and applicable state and federal requirements.
- Decisions do not guarantee payment; governed by coverage documents and legal/regulatory requirements.
Clinical Background
Background: Casimersen (Amondys 45) is an antisense oligonucleotide therapy approved under accelerated approval to treat Duchenne muscular dystrophy (DMD) in patients with DMD gene mutations amenable to exon 45 skipping. Approval was based on increased dystrophin production, with confirmatory trials required to verify clinical benefit. Corticosteroids remain standard of care and are recommended to be used concurrently with exon-skipping therapies unless contraindicated.
Definitions and Key Terms
Initial Therapy Approval Requirements
Initial Therapy
Covered when ALL of the following are met for initial approval:
Approval duration: 6 months
Continuation Therapy Approval Requirements
Continuation Therapy
Covered when ALL of the following are met for continued therapy:
Approval duration: 6 months
Step Therapy and Concomitant Medications
| Step | Requirement | Notes |
|---|---|---|
| 1 | No defined step-therapy sequence prior to initiation of casimersen (Amondys 45). | Policy does not require trial and failure of a specific prior exon-skipping agent before starting casimersen. |
| Corticosteroid therapy | Amondys 45 must be prescribed concurrently with an oral corticosteroid unless contraindicated or clinically significant adverse effects occur. | If corticosteroid use is inadequate response is required for initial approval: adherent corticosteroid (e.g., prednisone, Emflaza, Agamree) for ≥ 6 months unless contraindicated; prior authorization is required for Emflaza and Agamree. |
Quantity Limits
Site of Care
No site-of-care restriction specified
No site-of-care restriction is specified in this policy section.
- Site-of-care: none specified for Amondys 45.
Additional Coding Notes
Prior authorization required; billing code C9075
Prior authorization is required for Amondys 45; use HCPCS code C9075 (Injection, casimersen, 10 mg) for billing.
- Prior authorization required for Amondys 45.
- Billing code: C9075 — Injection, casimersen, 10 mg.
Policy Revision History
4Q 2025 annual review: no changes made.
1Q 2025 annual review: updated Appendix C with new contraindication per prescribing information (serious hypersensitivity to casimersen or inactive ingredients); references reviewed and updated.
Added Agamree (vamorolone) as an oral corticosteroid option in Appendix B and to initial criteria.
1Q 2024 annual review: added criterion that member has not previously received gene replacement therapy for DMD (e.g., Elevidys); added Agamree to Appendix B; references reviewed.
New Georgia-specific policy created from CP.PHAR.470; 6MWT criterion changed from 300 meters to 180 meters to align with Department of Community Health request.
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