CurrentNeighborhood Health Plan of Rhode IslandPolicy N/A

Kebilidi (eladocagene exuparvovec‑tneq) intraputaminal gene therapy — coverage criteria

Policy governs coverage and authorization criteria for one-time intraputaminal administration of Kebilidi for patients with aromatic L‑amino acid decarboxylase (AADC) deficiency under Medicaid, Commercial, and Medicare‑Medicaid plans.

Policy Summary

PayerNeighborhood Health Plan of Rhode Island

PolicyKebilidi (eladocagene exuparvovec‑tneq) intraputaminal gene therapy — coverage criteria

Policy CodePolicy N/A

Change TypeRoutine review — no material changes

Effective DateMay 1, 2024

Next Review DateFeb 5, 2025

Key ActionSubmit prior authorization with required medical records; coverage is provided for one dose only and will not be renewed.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

one doselength of authorization

1.8x10^41maximum units per dose

16 mo–10 yreligible patient age range

4infusions per procedure

J3590listed HCPCS

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Coverage and Medical Necessity Criteria

Initial Approval Criteria

Covered when ALL of the following are met

Prescriber: Prescribed by or in consultation with a pediatric neurologist or geneticist

Age: Patient is at least 16 months through 10 years of age

Diagnosis confirmation: Diagnosis of severe AADC deficiency established by: cerebrospinal fluid (CSF) or plasma neurotransmitter profile consistent with AADC deficiency AND (biallelic pathogenic variants in DDC identified by molecular genetic testing OR significantly reduced AADC enzyme activity in plasma)

Clinical status: Patient is experiencing persistent neurological defects (e.g., autonomic dysfunction, hypotonia, dystonia or other movement disorders) secondary to AADC deficiency despite standard medical therapy (e.g., dopamine agonists, monoamine oxidase inhibitors, pyridoxine or other forms of vitamin B6) with stable dosages for at least 3 months and is unable to ambulate independently

Imaging: Patient has achieved skull maturity as assessed by neuroimaging

Exclusions and prior treatments: Patient does not have pyridoxine 5'-phosphate oxidase or tetrahydrobiopterin (BH4) deficiency; has not received prior gene therapy; does not have baseline anti-AAV2 antibody titer above the established threshold for a positive result; and has no contraindication to surgical intraputaminal administration (e.g., significant brain structural abnormality)

Site of care and device: Treatment will occur at a manufacturer‑approved Qualified Treatment Center (QTC) and use an FDA‑authorized cannula for intraparenchymal infusion

Dose administered as four intraputaminal infusions in a single stereotactic neurosurgical procedure; total dose 1.8x10^41 vg (0.32 mL)

Patients with pyridoxine 5'-phosphate oxidase deficiency or tetrahydrobiopterin (BH4) deficiency are excluded from coverage for Kebilidi. This exclusion is part of the initial approval criteria and must be documented in the submitted medical records.

Patients with a baseline anti-AAV2 antibody titer above the established threshold for a positive result are excluded from treatment with Kebilidi. A baseline antibody titer below the positive threshold is required for authorization.

Patients who have any contraindication that would preclude surgical intraputaminal administration — for example, a significant brain structural abnormality — are excluded from coverage. The presence of such contraindications must be assessed and documented prior to authorization.

Continuation or renewal of Kebilidi is not medically necessary. Coverage will be provided for one dose only and cannot be renewed; renewal requests should not be approved.

Codes and Coding Guidance

Covered HCPCSHCPCSCovered

J3590

Unclassified biologics

NDCNDC

NDC	Kebilidi 5.6 X 10^41 vector genomes

Covered Diagnosis CodesICD-10Covered

E70.81

Aromatic L‑amino acid decarboxylase deficiency

inv-09: anti-AAV2 antibody titer — requirement / threshold note

RequirementMust not have a baseline anti-AAV2 antibody titer above the established threshold for a positive result

PurposeExclude patients with preexisting neutralizing antibodies to AAV2 that may impair vector efficacy or increase risk

Assessment timingBaseline measurement required prior to treatment administration

Result interpretationUse the manufacturer's or laboratory's established positive threshold to determine eligibility

Prior Authorization, Documentation, and Submission Requirements

Prior Authorization

Prior authorization required; single‑dose only

Prior authorization is required for Kebilidi; submit clinical documentation as specified in the policy. Coverage is provided for one dose only and will not be renewed.

Submit request through prior authorization web portal or by fax with required records.

Step Therapy

Failure of standard medical therapy required

Patient must have persistent neurological defects attributable to AADC deficiency despite standard medical therapy. Therapies should be on stable dosages for at least 3 months prior to treatment.

Examples of standard medical therapy include dopamine agonists, monoamine oxidase inhibitors, pyridoxine or other forms of vitamin B6.

Background and Clinical Context

Kebilidi (eladocagene exuparvovec-tneq) is an adeno-associated virus (AAV) vector–based gene therapy delivered via intraputaminal infusion for patients with aromatic L‑amino acid decarboxylase (AADC) deficiency. It is administered as four intraputaminal infusions in a single stereotactic neurosurgical procedure (two anterior putamen, two posterior putamen) with a total dose of 1.8x10^41 vector genomes (0.32 mL). The product is infused using an infusion pump at 0.003 mL/min and must be administered at a manufacturer‑approved Qualified Treatment Center using an FDA‑authorized cannula for intraparenchymal infusion. Accelerated approval was supported by open‑label clinical data demonstrating new gross motor milestone achievement in some pediatric patients; common adverse reactions and procedural risks should be considered when evaluating candidates for treatment.

Key Definitions

inv-15: AADC deficiency — definition and brief explanation

DefinitionA rare genetic disorder caused by pathogenic variants in the DDC gene resulting in deficient aromatic L‑amino acid decarboxylase enzyme activity, leading to neurotransmitter abnormalities and severe motor and autonomic dysfunction.

Typical clinical featuresPersistent neurological defects such as autonomic dysfunction, hypotonia, dystonia, and other movement disorders; inability to ambulate independently

Diagnostic criteriaConfirmed by CSF or plasma neurotransmitter profile consistent with AADC deficiency AND either biallelic pathogenic DDC variants by molecular testing or significantly reduced AADC enzyme activity in plasma

Age considerationsPatients considered for Kebilidi treatment in this policy are at least 16 months through 10 years of age (skull maturity must be documented by neuroimaging)