Subject: phenylbutyrate-Buphenyl-Pheburane 2121-A SGM P2022a

Drug

BUPHENYL  (sodium phenylbutyrate)

PHEBURANE®  (sodium phenylbutyrate)

sodium phenylbutyrate

Policy:

       I.  INDICATIONS

            The indications below including FDA-approved indications and
            compendial uses are considered a covered benefit provided
            that all the approval criteria are met and the member has no
            exclusions to the prescribed therapy.

            FDA-Approved Indication
            A.  Buphenyl is indicated as adjunctive therapy in the chronic
                 management of patients with urea cycle disorders involving
                 deficiencies of carbamylphosphate synthetase (CPS),
                 ornithine transcarbamylase (OTC), or argininosuccinic acid
                 synthetase (AS). It is indicated in all patients with
                 neonatal-onset deficiency (complete enzymatic deficiency,
                 presenting within the first 28 days of life). It is also
                 indicated in patients with late-onset disease (partial
                 enzymatic deficiency, presenting after the first month of
                 life) who have a history of hyperammonemic
                 encephalopathy. It is important that the diagnosis be made
                 early, and treatment initiated immediately to improve
                 survival. Any episode of acute hyperammonemia should be
                 treated as a life-threatening emergency.

            B.  Pheburane is indicated as adjunctive therapy to standard of
                 care, which includes dietary management, for the chronic
                 management of adult and pediatric patients with urea cycle
                 disorders (UCDs), involving deficiencies of
                 carbamylphosphate synthetase (CPS), ornithine
                 transcarbamylase (OTC) or argininosuccinic acid synthetase
                 (AS).

             Compendial Use
             Arginase deficiency

             All other indications are considered
             experimental/investigational and not medically necessary.

 
     II.  DOCUMENTATION

           Submission of the following information is necessary to initiate
           the prior authorization review:
           A.  Initial requests:
                1.  Enzyme assay, biochemical, or genetic testing results
                     supporting diagnosis; and
                2.  Lab results documenting baseline plasma ammonia
                     levels.
           B.  Continuation of therapy requests: lab results documenting a
                reduction in plasma ammonia levels from baseline.

 
   III.  CRITERIA FOR INITIAL APPROVAL

           Authorization of 12 months may be granted for chronic
           management of urea cycle disorder (UCD) including arginase
           deficiency, when both of the following criteria are met:
           1.  The diagnosis is confirmed by enzymatic, biochemical, or
                genetic testing.
           2.  The member has elevated plasma ammonia levels at
                baseline.

 
    IV.  CONTINUATION OF THERAPY  

           Authorization of 12 months may be granted for continued
           treatment in members requesting reauthorization for chronic
           management of a urea cycle disorder (UCD) including arginase
           deficiency, who are experiencing benefit from therapy as
           evidenced by a reduction in plasma ammonia levels from
           baseline.

Place of Service:

Outpatient

The above policy is based on the following references:

1. Buphenyl [package insert]. Lake Forest, IL: Horizon Pharma USA, Inc.; March 2021.
2. Mew NA, Lanpher BC. Urea Cycle Disorders Overview. In: Pagon RA, Adam MP, Ardinger HH, et. al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017 [updated June 22, 2017]. Available at: https://www.ncbi.nlm.nih.gov/books/NBK1217/?report=printable.
3. Häberle J, Boddaert N, Burlina A, et al. Suggested guidelines for the diagnosis and management of urea cycle disorders. J Inherit Metab Dis. 2019;42(6):1192-1230.
4. Wong D, Cederbaum S, Crombez, E. Arginase Deficiency. GeneReviews. August 2014; http://www.ncbi.nlm.nih.gov/books/NBK1159/.
5. Clinical Consult: CVS Caremark. Clinical Programs Review. Focus on Enzyme Disorders Programs; January 2021.
6. Pheburane [package insert]. Bryn Mawr, PA: Medunik USA, Inc.; June 2022

Copyright Aetna Inc. All rights reserved. Pharmacy Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.

October 02, 2022