CurrentPremera BluecrossPolicy 5.01.642

MEDICAL POLICY 5.01.642

Defines medical necessity criteria, coding, and authorization details for Kebilidi and Lenmeldy gene therapies for AADC deficiency and metachromatic leukodystrophy (MLD) respectively; states investigational uses and repeat treatment policy and that therapies are managed under the medical benefit.

Policy Summary

PayerPremera Bluecross

PolicyMEDICAL POLICY 5.01.642

Policy CodePolicy 5.01.642

Change TypeCoverage criteria added; coding update

Effective DateMar 1, 2025

Next Review Date

Key ActionProvide required diagnostic confirmation and specialist documentation and submit authorization requests (non-formulary exception reviews may be approved up to 12 months); report Lenmeldy using J3391 (effective 07/01/25) and Kebilidi using J3590.

POLICY UPDATE CHANGES

Added coverage criteria for Lenmeldy (atidarsagene autotemcel) and added Lenmeldy to unlisted HCPCS code J3590

Added coverage criteria for Kebilidi (eladocagene exuparvovec-tneq)

Coding update: Added new HCPCS code J3391 for Lenmeldy effective 07/01/25

Clarified that authorizations for all drugs listed may be approved up to 12 months and are subject to FDA dosing and administration

2Covered Gene Therapies Listed

12Max initial approval duration (months)

0Repeat treatments covered

07/01/2025

Lenmeldy HCPCS code effective

Coverage Summary

This policy defines medical necessity criteria, coding, authorization, and benefit management for two single-administration gene therapies: Kebilidi (eladocagene exuparvovec-tneq) and Lenmeldy (atidarsagene autotemcel). Both therapies are managed under the medical benefit. Coverage is covered with criteria when the specific medical necessity criteria in the policy are met (e.g., diagnostic confirmation, age and functional thresholds, specialist prescribing). All other uses and repeat treatments of Kebilidi and Lenmeldy are considered investigational. Authorizations for these therapies may be approved for up to 12 months, and product-specific FDA dosing and administration information applies.

Age for Kebilidi>= 18 months

GMFC-MLD requirementGMFC-MLD level 0 with ataxia or 1

IQ requirementIQ >= 85 on age-appropriate testing

Policy effective2025-03-01

Last review2025-07-01

Kebilidi (eladocagene exuparvovec-tneq) — Initial Therapy Criteria

Kebilidi (eladocagene exuparvovec-tneq) - Medical Necessity

Kebilidi may be considered medically necessary when ALL of the following are met:

ALL of the following

Individual is aged 18 months or older
Diagnosed with aromatic L-amino acid decarboxylase (AADC) deficiency confirmed by identification of biallelic mutations in the DDC gene
Has the severe phenotype of AADC deficiency defined as having no motor milestone achievement at baseline and no clinical response to standard of care therapies (e.g., dopamine receptor agonist or pyridoxine)
Kebilidi is being prescribed by or in consultation with a specialist in pediatric neurology, a movement disorder specialist, or a clinical geneticist specializing in management of AADC deficiency

Lenmeldy (atidarsagene autotemcel) — Initial Therapy Criteria

Lenmeldy (atidarsagene autotemcel) - Medical Necessity

Lenmeldy may be considered medically necessary for treatment of metachromatic leukodystrophy (MLD) when ALL of the following are met:

ALL of the following

Diagnosed with MLD confirmed by ALL of the following:
- Arylsulfatase-A (ARSA) gene activity below the normal range in peripheral blood mononuclear cells or fibroblasts
- Identification of two known or novel disease-causing ARSA alleles
- 24-hour urine collection shows elevated sulfatide levels
ONE of the age/clinical state criteria

Investigational and Not Covered

Investigational / Not Covered

Restrictions that render treatment investigational:

ALL of the following

All other uses of Kebilidi and Lenmeldy for conditions not outlined in this policy are considered investigational
Repeat treatment of Kebilidi and Lenmeldy is considered investigational

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Applicable Codes

HCPCS - LenmeldyHCPCSCovered

J3391

Injection, atidarsagene autotemcel, per treatment (Lenmeldy) (new code effective 07/01/25)

HCPCS - Kebilidi reportingHCPCSCovered

J3590

Unclassified biologics (use to report: Kebilidi)

Provider Actions / Authorization & Documentation

Prior Authorization

Authorization required and length

Non-formulary exception reviews and other authorization reviews for Kebilidi and Lenmeldy may be approved up to 12 months; therapies are managed through the medical benefit.

Authorizations may be approved for up to 12 months
Therapies are managed through the medical benefit

Documentation Required

Diagnostic confirmation required

Provide genetic and laboratory confirmation per policy criteria for the indicated diagnosis.

For AADC deficiency: identification of biallelic mutations in the DDC gene

Clinical Evidence

13 pediatricKebilidi pivotal trial: Phase 2 PTC-AADC-GT-002 enrolled 13 pediatric individuals; 67% achieved a new gross motor milestone at Week 48

67% at Wk48Percentage of treated Kebilidi participants who achieved a new gross motor milestone by Week 48

39 vs 49Lenmeldy evidence: 39 treated children (trials + EAP) compared to 49 natural history controls

Improved survival & slowed progressionLenmeldy: improved survival in pre-symptomatic late-infantile (PSLI) at 6 years and slowed motor/cognitive progression in other specified subgroups

Both Kebilidi and Lenmeldy have received FDA approval and this policy references the pivotal clinical trial efficacy and safety data that supported those approvals (for example, the Phase 2 PTC-AADC-GT-002 data for Kebilidi and the single-arm trials and expanded access program data for Lenmeldy). The policy also references the Gross Motor Function Classification for MLD (GMFC-MLD) as part of Lenmeldy eligibility and related background evidence.

Background and Definitions

Background: This policy addresses single-administration gene therapies for rare pediatric genetic diseases. Kebilidi is indicated for severe aromatic L-amino acid decarboxylase (AADC) deficiency and was granted FDA approval supported by Phase 2 trial data. Lenmeldy is an ex vivo autologous hematopoietic stem cell gene therapy indicated for certain presentations of metachromatic leukodystrophy (MLD) and was approved based on data from clinical trials and an expanded access program. The policy uses the GMFC-MLD classification to define motor function thresholds relevant to Lenmeldy eligibility.

Term	Definition
GMFC-MLD	Gross Motor Function Classification in Metachromatic Leukodystrophy — levels 0 through 6 describing motor function (Level 0: walking without support with quality of performance normal for age; Level 1: walking without support but with reduced quality of performance; Level 2–6: progressive loss of sitting, locomotion, head and trunk control as defined in the policy)
AADC deficiency confirmation	Identification of biallelic mutations in the DDC gene

Revision History

2024-07-09policy_approval

New policy approved adding coverage criteria for Lenmeldy (atidarsagene autotemcel) and listing Lenmeldy under the unclassified biologics reporting instructions (J3590 as noted at time of addition).

2024-08-01history_note

History entry dated 08/01/24 documents the new policy approval on July 9, 2024 and the addition of Lenmeldy to the unlisted HCPCS reporting instruction (J3590).

2025-02-11annual_review

Annual review approved; policy updated to add coverage criteria for Kebilidi (eladocagene exuparvovec-tneq).

Policy Summary

PayerPremera Bluecross

PolicyMEDICAL POLICY 5.01.642

Policy CodePolicy 5.01.642

Change TypeCoverage criteria added; coding update

Effective DateMar 1, 2025

Next Review Date

On This Page

Has not previously received treatment with a gene therapy

Does not have neutralizing antibodies to adeno-associated virus serotype 2 (AAV2)

Note: Presence of neutralizing antibodies to AAV2 is an exclusion and may result in claim denial; providers should ensure testing and document results prior to authorization.

Kebilidi will be administered

Was diagnosed with MLD when aged 6 years or younger AND currently has no clinical signs or symptoms related to their MLD diagnosis (including but not limited to delay in expected achievement of independent standing or independent walking) AND documented normal neurological evaluation within the last 6 months

Has been diagnosed with MLD between 30 months and 6 years of age AND currently has a Gross Motor Function Classification (GMFC-MLD) level of 0 with ataxia or 1 AND currently has an intelligence quotient (IQ) of 85 or greater on age-appropriate neurodevelopmental testingGMFC-MLD level 0 with ataxia or 1; IQ >= 85

GMFC-MLD levels defined per policy

Lenmeldy is being prescribed by or in consultation with a neurologist or a prescriber who specializes in MLD

Has not previously received treatment with a hematopoietic stem cell transplant

Has not previously received treatment with a gene therapy

Lenmeldy will be administered

For MLD: ARSA activity below the normal range in peripheral blood mononuclear cells or fibroblasts

For MLD: identification of two known or novel disease‑causing ARSA alleles

For MLD: 24‑hour urine collection showing elevated sulfatide levels

Documentation Required

Specialist involvement required

Specialist involvement is required for prescribing or in consultation for each therapy as specified in the medical necessity criteria.

Kebilidi: prescribed by or in consultation with a pediatric neurologist, a movement disorder specialist, or a clinical geneticist specializing in AADC deficiency
Lenmeldy: prescribed by or in consultation with a neurologist or a prescriber who specializes in MLD

Denial Risk

Neutralizing antibodies exclusion for Kebilidi

Claims may be denied if the individual has neutralizing antibodies to adeno‑associated virus serotype 2 (AAV2).

Denial Risk

Prior gene therapy or HSCT exclusion

Claims may be denied for individuals who previously received gene therapy; prior hematopoietic stem cell transplant is an exclusion for Lenmeldy.

Prior gene therapy is an exclusion for both Kebilidi and Lenmeldy
Prior hematopoietic stem cell transplant is an exclusion for Lenmeldy

Billing Rule

Coding for Lenmeldy

Coding guidance for Lenmeldy reporting.

HCPCS J3391: Injection, atidarsagene autotemcel, per treatment (Lenmeldy) — new code effective 07/01/25

Billing Rule

Coding for Kebilidi

Coding guidance for Kebilidi reporting.

Report Kebilidi using unclassified biologics code J3590 (use to report Kebilidi)

2025-03-01policy_effective_date

Policy effective date aligned to 03/01/2025 reflecting updates including the Kebilidi coverage criteria added during the February 2025 review.

2025-07-01coding_update_effectiveLatest

Coding update effective 07/01/25: new HCPCS code J3391 established for Lenmeldy (Injection, atidarsagene autotemcel, per treatment); replaces prior instruction to report Lenmeldy via J3590.

2025-07-01clarificationLatest

Non-material clarification: authorizations for therapies listed in this policy may be approved up to 12 months and therapies are subject to FDA dosing and administration prescribing information.