CurrentUnitedHealthcarePolicy 2025D0136A

Kebilidi (Eladocagene Exuparvovec‑Tneq) for AADC deficiency

Defines UnitedHealthcare coverage criteria for Kebilidi gene therapy for patients with aromatic L‑amino acid decarboxylase (AADC) deficiency and explains documentation, dosing, and lifetime treatment limits for affected members.

Policy Summary

PayerUnitedHealthcare

PolicyKebilidi (Eladocagene Exuparvovec‑Tneq) for AADC deficiency

Policy CodePolicy 2025D0136A

Change TypeRoutine review — no material changes

Effective DateAug 1, 2025

Next Review Date

Key ActionObtain prior authorization with documentation of genetic confirmation of biallelic DDC mutations, decreased AADC enzyme activity, skull maturity, prior therapies tried, and anti‑AAV2 antibody titer results.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

one lifetimemaximum treatments authorized per patient

≤ 60 daysauthorization duration

1.8 x 10^11pivotal study dose (vg)

13 patientspivotal trial size

E70.81diagnosis code

Coverage Criteria for Kebilidi (Eladocagene Exuparvovec-Tneq)

Initial coverage (medically necessary) criteria

Covered when ALL of the following are met:

Eligibility: Patient has genetically confirmed AADC deficiency due to biallelic mutations in the DDC gene

Submit medical records documenting genetic confirmation.

Clinical features: Patient has one or more typical clinical characteristics of AADC deficiency (e.g., hypotonia, oculogyric crises, dystonia, hypokinesia, autonomic dysfunction, developmental delay)

Document clinical characteristics in medical records.

Enzyme activity: Decreased AADC enzyme activity in plasma per current laboratory standards

Laboratory reports demonstrating decreased AADC enzyme activity must be provided.

Policy Summary

PayerUnitedHealthcare

PolicyKebilidi (Eladocagene Exuparvovec‑Tneq) for AADC deficiency

Policy CodePolicy 2025D0136A

Change TypeRoutine review — no material changes

Effective DateAug 1, 2025

Next Review Date

SourceLink

On This Page

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Skull maturity: Patient has achieved skull maturity as confirmed by neuroimaging sufficient for stereotactic neurosurgical administration

Provide neuroimaging confirming skull maturity for stereotactic procedure.

Refractory to standard therapy: Persistent symptoms despite use of standard medical therapy (e.g., dopamine agonists, monoamine oxidase inhibitors, pyridoxine, other forms of vitamin B6)

Document prior therapies tried and ongoing symptoms despite therapy.

Functional status: Patient is unable to ambulate independently

Functional status should be documented in clinical notes.

Anti-AAV2 antibody titer is not higher than 1:1200 or > 1 optical density value by ELISA

Provide anti-AAV2 antibody titer results (≤ 1:1200 or ≤ 1 OD by ELISA).

Specialist prescriber: Prescribed by a neurologist or neurosurgeon

Prescriber specialty must be evident in the prescription or medical record.

No prior gene therapy: Patient has not previously received treatment with Kebilidi or other gene therapy for AADC deficiency in their lifetime

Provide history confirming no prior gene therapy treatment.

Dosing is in accordance with the United States Food and Drug Administration approved labeling

Administer per FDA‑approved labeling.

Authorization limits: Authorization will be issued for no more than one treatment per lifetime and for no longer than 60 days from approval

Prior authorization required; limits applied as stated.

Coverage will not be authorized when the member has an anti-AAV2 antibody titer above the policy thresholds. Specifically, no authorization is issued if the anti-AAV2 antibody titer is higher than 1:1200 or greater than 1 optical density (OD) value by ELISA. Prior receipt of Kebilidi or any other gene therapy for AADC deficiency in the member’s lifetime also excludes coverage. Authorization is further limited to one treatment per lifetime and will be issued for no longer than 60 days from approval.

Use of Kebilidi is considered not medically necessary for patients who do not meet all of the diagnostic and clinical eligibility criteria specified in this policy. Examples include absence of genetically confirmed biallelic DDC mutations, lack of documented decreased AADC enzyme activity in plasma, failure to demonstrate skull maturity appropriate for stereotactic neurosurgical administration, ongoing responsiveness to standard medical therapy (i.e., symptoms are not persistent despite treatment), ability to ambulate independently, or an anti-AAV2 antibody titer that exceeds 1:1200 or > 1 OD by ELISA. Such cases should not be authorized under this policy.

Applicable Codes and Laboratory Thresholds

Applicable Codes (reference)mixed

C9399	Unclassified drugs or biologicals.
J3590	Unclassified biologics.
E70.81	Aromatic L-amino acid decarboxylase (AADC) deficiency

Anti‑AAV2 antibody titer — required threshold

Required anti-AAV2 antibody thresholdAnti-AAV2 antibody titer must not be higher than 1:1200 or greater than 1.0 optical density by ELISA

Test methodEnzyme‑linked immunosorbent assay (ELISA) reporting optical density (OD)

Consequence of exceeding thresholdNo authorization if titer is higher than 1:1200 or >1 OD by ELISA

Documentation requirementSubmit antibody titer results as part of medical record for prior authorization

Related eligibility conditionAnti‑AAV2 threshold is one of multiple required criteria for coverage of Kebilidi

Provider Requirements and Authorization Process

Prior Authorization

Prior Authorization Required

Prior authorization is required. Requests must include complete documentation of diagnostic criteria, eligibility, and adherence to the one-treatment-per-lifetime limit. Authorization will be issued for no more than one treatment per lifetime and for no longer than 60 days from approval.

One treatment per lifetime limit
Authorization valid ≤ 60 days from approval

Step Therapy

Required Prior Therapy / Persistent Symptoms

The patient must have persistent symptoms of AADC deficiency despite standard medical therapy. Documentation should confirm failure or inadequate response to therapies such as dopamine agonists, monoamine oxidase inhibitors, pyridoxine, or other forms of vitamin B6 prior to approval.

Document trial and inadequate response to standard medical therapies (e.g., dopamine agonists, MAO inhibitors, pyridoxine)
Confirm persistent symptoms (e.g., hypotonia, oculogyric crises, dystonia, hypokinesia, autonomic dysfunction, developmental delay)

Documentation Required

Documentation to Submit

Submit medical records that demonstrate all of the following: genetic confirmation of AADC deficiency, decreased AADC enzyme activity, clinical characterization of symptoms, skull maturity for stereotactic neurosurgical administration, anti-AAV2 antibody testing, prescribing specialist, and prior treatment history.

Genetically confirmed AADC deficiency due to biallelic DDC gene mutations
Decreased AADC enzyme activity in plasma per current laboratory standards
Clinical records documenting typical AADC deficiency characteristics (e.g., hypotonia, oculogyric crises, dystonia, hypokinesia, autonomic dysfunction, developmental delay)
Neuroimaging confirming skull maturity for stereotactic neurosurgical administration
Anti-AAV2 antibody titer ≤ 1:1200 or ≤ 1 optical density by ELISA
Prescriber is a neurologist or neurosurgeon
Documentation that the patient has not previously received Kebilidi or other gene therapy for AADC deficiency

Denial Risk

Denial Triggers

Denial may be triggered if required documentation is missing or does not meet criteria. Specific triggers include lack of genetic confirmation, absent or nonconforming AADC enzyme activity results, failure to document persistent symptoms despite standard therapy, prior receipt of Kebilidi or other gene therapy, skull immaturity on imaging, anti-AAV2 antibody titers above allowable thresholds, or prescribing clinician not a neurologist/neurosurgeon.

Missing genetic confirmation of biallelic DDC mutations
No decreased AADC enzyme activity documented per current laboratory standards
Insufficient documentation of persistent symptoms despite adequate trials of standard therapy
Evidence of prior Kebilidi or other gene therapy treatment
Neuroimaging does not confirm skull maturity
Anti-AAV2 antibody titer > 1:1200 or > 1 optical density by ELISA
Prescriber is not a neurologist or neurosurgeon

Diagnostic Definitions and Core Tests

Core diagnostic tests for AADCD (iNTD consensus)

iNTD core diagnostic tests (set of three)Low CSF 5‑HIAA, HVA, MHPG with normal CSF pterins and increased CSF L‑Dopa, 3‑OMD, 5‑HTP; genetic testing showing compound heterozygous or homozygous DDC variants; decreased AADC enzyme activity in plasma

Diagnostic confirmation rulePerform genetic testing and at least two of the three core diagnostic tests should be positive; perform all three when local resources allow

Genetic requirementGenetic diagnosis demonstrating compound heterozygous or homozygous disease‑causing variants in the DDC gene (biallelic mutations)

Biochemical requirementDecreased AADC enzyme activity measured in plasma per current laboratory standards

CSF neurotransmitter profile specificsLow CSF 5‑HIAA, HVA and MHPG with normal pterins and increased CSF L‑Dopa, 3‑OMD and 5‑HTP

Background on AADC Deficiency and Therapy

Aromatic L‑amino acid decarboxylase (AADC) deficiency is a rare neurometabolic disorder caused by biallelic pathogenic variants in the DDC gene that result in deficient AADC enzyme activity and impaired synthesis of monoamine neurotransmitters. Clinical manifestations commonly include hypotonia, oculogyric crises, dystonia, hypokinesia, autonomic dysfunction, and developmental delay, and many affected patients are unable to ambulate independently. Kebilidi (eladocagene exuparvovec‑Tneq) is an intraputaminal gene therapy administered via stereotactic neurosurgery intended to restore AADC function; coverage is limited to patients who meet the specific diagnostic, laboratory, functional, and antibody criteria outlined in this policy.