CurrentCareSourcePolicy N/A

Nexviazyme (avalglucosidase alfa-ngp) coverage for late-onset Pompe disease

Defines prior authorization and medical necessity criteria for Nexviazyme when used to treat late-onset Pompe disease for CareSource members in Arkansas PASSE.

Policy Summary

PayerCareSource

PolicyNexviazyme (avalglucosidase alfa-ngp) coverage for late-onset Pompe disease

Policy CodePolicy N/A

Change TypeAnnual review — no material changes

Effective DateApr 1, 2024

Next Review DateN/A

Key ActionObtain prior authorization and document genetic testing and enzyme assay confirming late-onset Pompe disease before initiating therapy.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

12 moinitial approval duration

12 moreauthorization duration

20 mg/kgdose ≥30 kg q2w

40 mg/kgdose <30 kg q2w

Coverage Criteria for Nexviazyme (avalglucosidase alfa-ngp)

Initial Therapy

Covered when ALL of the following are met:

Age: Member is at least 1 year of age>=1 year

Prescriber: Medication must be prescribed by or in consultation with a geneticist, neurologist, pulmonologist, or metabolic specialist

Genetic testing: Molecular genetic testing shows pathogenic mutation of the GAA genepathogenic mutation

Policy Summary

PayerCareSource

PolicyNexviazyme (avalglucosidase alfa-ngp) coverage for late-onset Pompe disease

Policy CodePolicy N/A

Change TypeAnnual review — no material changes

Effective DateApr 1, 2024

Next Review DateN/A

Key ActionObtain prior authorization and document genetic testing and enzyme assay confirming late-onset Pompe disease before initiating therapy.

SourceLink

On This Page

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Diagnosis of late-onset Pompe disease confirmed by an enzyme activity assay showing GAA deficiency (2% to 40% of normal)

Clinical signs: Member must show signs or symptoms (e.g., motor weakness, reduced respiratory parameters)

Dosing

Initial dosing and prescriber/testing requirements

Dose <30 kg: Actual body weight less than 30 kg: 40 mg/kg IV infusion every 2 weeks40 mg/kg q2w

Quantity limit applies by weight

Dose ≥30 kg: Actual body weight 30 kg or greater: 20 mg/kg IV infusion every 2 weeks20 mg/kg q2w

Quantity limit applies by weight

Prescriber requirement: Medication must be prescribed by or in consultation with a geneticist, neurologist, pulmonologist, or metabolic specialist

Prior authorization required

Initial testing: Molecular genetic testing showing pathogenic GAA mutation and an enzyme activity assay demonstrating GAA deficiency (2% to 40% of normal)2%–40%

Required for initial authorization

Reauthorization / Continuation Therapy

Covered when ALL of the following are met:

Reauthorization documentation: Chart notes document positive clinical response such as improved or stabilized respiratory muscle strength (e.g., FVC) or functional endurance (e.g., 6-minute walk test)

Approved for additional 12 months if met

Reauthorization

Reauthorization requires documentation of clinical benefit.

Clinical benefit: Chart notes must document positive clinical response such as improved or stabilized respiratory muscle strength (e.g., forced vital capacity) or improved functional endurance (e.g., 6-minute walk test)

If met, approve for 12 months

CareSource considers Nexviazyme (avalglucosidase alfa‑ngp) not medically necessary for the treatment of conditions that are not listed in this document (off‑label indications). Requests for Nexviazyme for off‑label indications may be denied; providers should refer to the Off‑Label policy for guidance.

Any indication other than late‑onset Pompe disease (acid alpha‑glucosidase [GAA] deficiency presenting beyond infancy) is considered not medically necessary for Nexviazyme. Coverage is limited to the diagnosis specified in this policy.

Coding and Test Results

Billing code notesHCPCS

J-code updated (unspecified)

Document notes an updated J code but does not specify the exact code in the policy text.

GAA enzyme activity

Reported GAA enzyme activity range2% to 40% of normal

Purpose of assayUsed to confirm diagnosis of late-onset Pompe disease (GAA deficiency)

Role in initial authorizationRequired evidence alongside molecular genetic testing showing a pathogenic GAA mutation

Provider Requirements and Documentation

Prior Authorization

Prior Authorization and Prescriber Requirement

Prior authorization is required. Nexviazyme (avalglucosidase alfa-ngp) is a medical benefit in Arkansas PASSE and must be prescribed by or in consultation with a geneticist, neurologist, pulmonologist, or metabolic specialist.

Benefit type: Medical
Prior authorization required
Prescriber requirement: geneticist, neurologist, pulmonologist, or metabolic specialist

Documentation Required

Initial Authorization Documentation

Initial authorization requires documentation of molecular genetic testing showing a pathogenic GAA mutation and an enzyme activity assay confirming GAA deficiency (approximately 2%–40% of normal). Member must be at least 1 year of age and have signs or symptoms of late‑onset Pompe disease (e.g., motor weakness, reduced respiratory parameters). Weight‑based dosing: <30 kg = 40 mg/kg IV every 2 weeks; ≥30 kg = 20 mg/kg IV every 2 weeks. Approval length: 12 months when criteria are met.

Age requirement: ≥ 1 year
Molecular genetic testing: pathogenic GAA mutation
Enzyme activity assay: GAA deficiency (2%–40% of normal)
Clinical signs/symptoms documented (motor weakness, respiratory impairment)
Dosing: <30 kg = 40 mg/kg IV q2 weeks; ≥30 kg = 20 mg/kg IV q2 weeks
Initial approval duration: 12 months

Documentation Required

Reauthorization Documentation

For reauthorization, chart notes must document a positive clinical response such as improved or stabilized respiratory muscle strength (e.g., forced vital capacity) or improved/stabilized functional endurance (e.g., 6‑minute walk test). If documented, approval may be renewed for an additional 12 months.

Documented clinical response required at reauthorization (respiratory or functional improvement/stabilization)
Reauthorization duration: 12 months

Step Therapy

No step therapy requirements specified for Nexviazyme.

Denial Risk

Off‑Label Exclusion

Requests for Nexviazyme for indications not listed (off‑label) are considered not medically necessary and may be denied. Refer to the Off‑Label policy for other indications.

Background

Pompe disease is caused by deficiency of the enzyme acid alpha‑glucosidase (GAA)late‑onset Pompe disease (LOPD); this policy addresses treatment of LOPD. Nexviazyme is an enzyme replacement therapy indicated for LOPD and requires documentation of clinical benefit at reauthorization, for example improved or stabilized respiratory muscle strength (e.g., forced vital capacity) or functional endurance (e.g., 6‑minute walk test). If reauthorization criteria are met, the medication may be approved for an additional 12 months.

Definitions

Late-onset Pompe disease (LOPD)

DefinitionPompe disease presenting beyond infancy (late-onset Pompe disease, LOPD); typically does not present with cardiomyopathy and has variable skeletal muscle weakness

Clinical presentationProgressive skeletal muscle weakness and reduced respiratory function; signs may include motor weakness and reduced respiratory parameters (e.g., reduced FVC)

Indication for NexviazymeNexviazyme is indicated only for late-onset Pompe disease and not for infantile-onset forms

GAA deficiency

Enzyme nameAcid alpha-glucosidase (GAA)

PathophysiologyInherited GAA deficiency causes lysosomal glycogen accumulation leading to progressive muscle damage (glycogen storage disease type II)

Diagnostic roleGAA deficiency is confirmed by enzyme activity assay (2%–40% of normal) and molecular genetic testing for pathogenic GAA mutations

Step Therapy / Prior Biologic Requirements

Step	Requirement
1	No step therapy or prior biologic requirement specified in the policy text; prior authorization is required for Nexviazyme (medical benefit).

Quantity Limits and Dosing Summary

Nexviazyme (avalglucosidase alfa-ngp) dosing

Dose for members <30 kg40 mg/kg IV infusion every 2 weeks

Dose for members ≥30 kg20 mg/kg IV infusion every 2 weeks

Dosing frequencyEvery 2 weeks (q2w)

Site of Care

Note

Infusion (site of care)

Nexviazyme is administered as an intravenous infusion; the policy does not restrict site of care beyond noting infusion administration.

Administered as IV infusion.
Site of care is not further restricted in the policy text.