CurrentNeighborhood Health Plan of Rhode IslandPolicy N/A

Carglumic acid (Carbaglu) coverage for hyperammonemia due to NAGS deficiency, PA, MMA

Defines prior authorization, indications covered (FDA-approved and compendial), documentation required, initial and continuation/reauthorization criteria, and authorization duration for carglumic acid (Carbaglu) for N-acetylglutamate synthase (NAGS) deficiency, propionic acidemia (PA), and methylmalonic acidemia (MMA).

Policy Summary

PayerNeighborhood Health Plan of Rhode Island

PolicyCarglumic acid (Carbaglu) coverage for hyperammonemia due to NAGS deficiency, PA, MMA

Policy CodePolicy N/A

Change TypeNo material change

Effective Date

Next Review Date

Key ActionSubmit enzyme assay, biochemical or genetic testing results and baseline plasma ammonia for initial requests; for continuation, submit labs documenting ammonia reduction (NAGS) or disease stability/improvement (MMA/PA).

POLICY UPDATE CHANGES

No material clinical/coverage changes for this policy.

3Covered Indications (NAGS, MMA, PA)

12Standard Authorization Duration (months)

1Requirement: diagnostic confirmation

Coverage Summary & Scope

Carglumic acid (Carbaglu) is indicated as adjunctive therapy to standard of care for treatment of acute and chronic hyperammonemia due to N-acetylglutamate synthase (NAGS) deficiency and as adjunctive therapy for acute hyperammonemia due to propionic acidemia (PA) or methylmalonic acidemia (MMA). Concomitant use of other ammonia-lowering therapies (for example, alternate pathway medications or hemodialysis) and dietary protein restriction may be needed. Coverage stance: covered_with_criteria. Required documentation for authorization includes diagnostic confirmation (enzymatic, biochemical, or genetic testing for NAGS deficiency) and laboratory results (baseline plasma ammonia for initial requests and follow-up ammonia or evidence of clinical benefit for continuation requests).

Initial Therapy Criteria and Continuation / Reauthorization

Covered Indications (Initial and Continuation Authorization)

Carbaglu is covered for the FDA-approved and compendial indications when ALL of the following documentation and criteria are met:

ALL of the following

ONE of
- Acute hyperammonemia due to N-acetylglutamate synthase (NAGS) deficiency
- Chronic hyperammonemia due to N-acetylglutamate synthase (NAGS) deficiency (maintenance therapy)
- Acute hyperammonemia due to propionic acidemia (PA)
- Acute hyperammonemia due to methylmalonic acidemia (MMA)
Diagnosis is confirmed by enzymatic, biochemical, or genetic testing
For NAGS deficiency specifically; enzyme assay, biochemical or genetic testing required.
Initial requests: lab results documenting baseline plasma ammonia levels
Continuation (reauthorization) requests: lab results documenting a reduction in plasma ammonia levels from baseline for NAGS deficiency, or disease stability/improvement for MMA or PA
No member exclusions to the prescribed therapy
Member must have no exclusions to the prescribed therapy as per payer policy.

Authorization Duration

When criteria met:

ALL of the following

Authorization of 12 months may be granted for members with a diagnosis of NAGS deficiency
Authorization of 12 months may be granted for members with a diagnosis of methylmalonic acidemia
Authorization of 12 months may be granted for members with a diagnosis of propionic acidemia

Not Covered

All other indications not listed above are considered:

ALL of the following

Experimental, investigational, and not medically necessary

Prior Authorization & Documentation Requirements

Prior Authorization

Prior authorization required

Submit enzyme assay, biochemical, or genetic testing results supporting the diagnosis (for NAGS deficiency) and laboratory results documenting baseline plasma ammonia for initial prior authorization requests; for continuation requests, submit labs documenting reduction in plasma ammonia from baseline for NAGS deficiency or evidence of disease stability/improvement for MMA or PA.

Documentation Required

Diagnosis confirmation required

Provide enzymatic, biochemical, or genetic testing results to confirm the diagnosis as part of the prior authorization submission. For initial requests, include baseline plasma ammonia laboratory results. For continuation/reauthorization, include follow-up labs demonstrating a decrease in plasma ammonia from baseline for NAGS deficiency or evidence of disease stability or improvement for MMA or PA.

Enzyme assay, biochemical, or genetic test results confirming diagnosis
Baseline plasma ammonia level (initial requests)
Follow-up plasma ammonia showing reduction from baseline (NAGS continuation) or documentation of disease stability/improvement (MMA/PA continuation)

Definitions & Background

Carglumic acid (Carbaglu) is indicated in pediatric and adult patients as adjunctive therapy to standard of care for the treatment of acute hyperammonemia due to NAGS deficiency; it is also indicated as maintenance therapy for chronic hyperammonemia due to NAGS deficiency, and as adjunctive therapy for acute hyperammonemia due to PA or MMA. During acute episodes and maintenance therapy, concomitant ammonia-lowering therapies and protein restriction may be required.

Definition: NAGS deficiency — N-acetylglutamate synthase deficiency, a condition causing hyperammonemia confirmed by enzymatic, biochemical, or genetic testing.

Policy Summary

PayerNeighborhood Health Plan of Rhode Island

PolicyCarglumic acid (Carbaglu) coverage for hyperammonemia due to NAGS deficiency, PA, MMA

Policy CodePolicy N/A

Change TypeNo material change

Effective Date

Next Review Date

On This Page

OpenPayer

Carglumic acid (Carbaglu) coverage for hyperammonemia due to NAGS deficiency, PA, MMA

Coverage Summary & Scope

Initial Therapy Criteria and Continuation / Reauthorization

Prior Authorization & Documentation Requirements

Applicable Codes

Evidence & References

Definitions & Background