Subject: Sodium phenylbutyrate products 2121-A SGM P2023

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.

          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).

          C.  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).

          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:
          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 20kg 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 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 (updated May 20, 2020); http://www.ncbi.nlm.nih.gov/books/NBK1159/.
5. Pheburane [package insert]. Bryn Mawr, PA: Medunik USA, Inc.; June 2022
6. Olpruva [package insert]. Newton, MA: Acer Therapeutics, Inc.; December 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.

June 18, 2023