CurrentNeighborhood Health Plan of Rhode IslandPolicy N/A

Coverage Criteria for Sodium Phenylbutyrate Therapies for Urea Cycle Disorders

Defines coverage and prior authorization criteria for sodium phenylbutyrate products (Buphenyl, Pheburane, Olpruva, and generic) for chronic management of urea cycle disorders (including arginase deficiency) for Neighborhood Health Plan of Rhode Island members.

Policy Summary

PayerNeighborhood Health Plan of Rhode Island

PolicySodium phenylbutyrate therapies for urea cycle disorders — coverage with criteria

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateN/A

Next Review DateN/A

Key ActionSubmit enzyme assay or genetic testing and baseline plasma ammonia results with initial prior authorization requests; continuation requests must show reduced plasma ammonia from baseline.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

12 monthsauthorization duration

3 + genericproducts listed

>=20 kg, BSA>=1.2Olpruva eligibility

Arginase deficiencycompendial coverage

Coverage Criteria

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inv-01: Initial Approval

Authorization of 12 months may be granted when ALL of the following are met:

Initial approval for chronic UCD management: Diagnosis confirmed by enzymatic, biochemical, or genetic testing.

From policy: diagnosis confirmation required via enzymatic, biochemical, or genetic testing.

Initial approval for chronic UCD management: Member has elevated plasma ammonia levels at baseline.

Baseline elevated plasma ammonia required per policy.

Initial approval for Olpruva requests: If the request is for Olpruva, patient weight >= 20 kg AND body surface area (BSA) >= 1.2 m2.weight >= 20 kg; BSA >= 1.2 m2

Olpruva-specific eligibility per FDA-approved indication.

inv-02: Continuation of Therapy

Authorization of 12 months may be granted for continued treatment when ALL of the following are met:

Continuation of therapy: Member is experiencing benefit from therapy as evidenced by a reduction in plasma ammonia levels from baseline.

Continuation requests must submit laboratory results documenting a reduction in plasma ammonia from baseline.

inv-03: Covered Indications

Covered indications (must meet approval criteria):

Covered indications: FDA-approved chronic management of urea cycle disorders (UCDs) involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS) (includes neonatal-onset and late-onset with hyperammonemic encephalopathy).

Per Buphenyl and Pheburane FDA indications.

Covered indications (product-specific): Olpruva is covered for chronic management of UCDs for patients weighing >= 20 kg with BSA >= 1.2 m2 (must also meet approval criteria).weight >= 20 kg; BSA >= 1.2 m2

Per Olpruva FDA-approved indication.

Compendial use: Arginase deficiency (compendial use) is a covered indication when the approval criteria are met.

All other indications beyond FDA-approved and listed compendial uses are considered experimental/investigational and not medically necessary.

All indications beyond the FDA‑approved uses and the specifically listed compendial use are considered experimental/investigational and therefore not medically necessary.

Indications that are not listed as either an FDA‑approved indication or the specified compendial use for arginase deficiency are considered not medically necessary.

Provider Actions and Documentation Requirements

Prior Authorization

Authorization duration and requirements

Prior authorization may be granted for up to 12 months when criteria for initial approval are met. Reauthorization for up to 12 months may be granted for members demonstrating continued benefit from therapy (see continuation documentation requirements).

Authorization duration: up to 12 months for initial approval
Reauthorization duration: up to 12 months for continuation requests

Documentation Required

Initial request documentation

Initial requests must include supporting diagnostic and baseline laboratory documentation to initiate prior authorization review.

Enzyme assay, biochemical, or genetic testing results supporting the diagnosis
Lab results documenting baseline plasma ammonia level

Documentation Required

Continuation request documentation

Continuation (reauthorization) requests must include objective evidence of benefit as part of the prior authorization review.

Lab results documenting a reduction in plasma ammonia levels from baseline

Denial Risk

Potential denial triggers

Requests that lack the required documentation demonstrating that approval criteria are met, or requests for indications considered experimental/investigational, may be denied as not medically necessary.

Missing diagnostic testing or baseline labs on initial requests
Missing evidence of ammonia reduction on continuation requests
Requests for uses outside of covered indications or without supportive evidence

Note

(Provider highlight)

Provider-impact: include all required documentation at time of submission to avoid delays or denials. For Olpruva-specific requests, ensure weight and BSA criteria are documented when applicable.

If requesting Olpruva, document patient weight ≥ 20 kg and BSA ≥ 1.2 m2
Include all lab and diagnostic reports as listed under Initial and Continuation requirements

Definitions

Urea cycle disorders (UCDs) — definitions and common enzyme deficiencies

Definition of UCDsUrea cycle disorders (UCDs) involve deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS).

FDA-approved scopeBuphenyl and Pheburane indicated as adjunctive therapy for chronic management of UCDs involving CPS, OTC, or AS

Olpruva-specific indicationOlpruva indicated as adjunctive therapy for adult and pediatric patients weighing >=20 kg and with BSA >=1.2 m2 for UCDs involving CPS, OTC, or AS

Clinical noteUCDs include neonatal-onset (complete enzymatic deficiency presenting within first 28 days) and late-onset (partial deficiency presenting after first month) with hyperammonemic encephalopathy

Buphenyl	sodium phenylbutyrate (brand)
Olpruva	sodium phenylbutyrate (brand)
Pheburane	sodium phenylbutyrate (brand)
sodium phenylbutyrate (generic)	generic sodium phenylbutyrate

OpenPayer

Coverage Criteria for Sodium Phenylbutyrate Therapies for Urea Cycle Disorders

Coverage Criteria

Coding and Product Eligibility

Provider Actions and Documentation Requirements

Background

Definitions