Subject: Sodium phenylbutyrate products 2121-A SGM P2024

Drug

BUPHENYL  (sodium phenylbutyrate )

OLPRUVA  (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.

          A.  FDA-Approved Indications
               1.  Buphenyl/sodium phenylbutyrate (generic) 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.

               2.  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).

               3.  Olpruva is indicated as adjunctive therapy to standard of care, which includes dietary
                    management, for the chronic management of adult and pediatric patients weighing 20 kg
                    or greater and with a body surface area (BSA) of 1.2 m² or greater, with urea cycle
                    disorders (UCDs) involving deficiencies of carbamylphosphate synthetase (CPS),
                    ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS).

          B.  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

          Urea Cycle Disorders (UCDs) and Arginase Deficiency
          Authorization of 12 months may be granted for chronic management of a urea cycle disorder
          (UCD), including arginase deficiency, when all of the following criteria are met:
          A.  The diagnosis is confirmed by enzymatic, biochemical, or genetic testing.
          B.  The member has elevated plasma ammonia levels at baseline.
          C.  If the request is for Olpruva, both of the following criteria are met:
               1.  Patient weighs 20 kg or greater.
               2.  Patient has a body surface area (BSA) of 1.2 m² or greater.


   IV.  CONTINUATION OF THERAPY

          Authorization of 12 months may be granted for continued treatment in members requesting
          reauthorization for an indication listed in Section III 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]. Deerfield, IL: Horizon Therapeutics USA, Inc.; March 2023.
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. Sun A, Crombez EA, Wong D. Arginase Deficiency. 2004 Oct 21 [Updated 2020 May 28]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews^® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2023. Available from: http://www.ncbi.nlm.nih.gov/books/NBK1159/.
5. Pheburane [package insert]. Princeton, NJ: Medunik USA, Inc.; August 2023.
6. Olpruva [package insert]. Newton, MA: Acer Therapeutics, Inc.; December 2022.
7. sodium phenylbutyrate [package insert]. Chestnut Ridge, NY: Par Pharmaceutical Companies, Inc.; July 2017.

 

 

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.

April 17, 2024