HCPCS Level II C9309: Injection, onasemnogene abeparvovec-brve, per treatment

HCPCS Level II code C9309 denotes a single-treatment administration of onasemnogene abeparvovec-brve, a gene therapy injection for eligible patients. This code matters nationally due to the high-cost, single-dose nature of the therapy, its implications for payer coverage policies, and the need for specialized delivery and follow-up care. Payers analyzed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.

Readers will learn how C9309 is used to represent the one-time intravenous gene therapy administration, the clinical contexts in which the product is delivered, and the administrative considerations payers apply for coverage and payment. The publication provides benchmarks where available, summaries of relevant policy updates, typical site-of-service implications, and coding considerations for service lines that manage high-cost, single-administration gene therapies.

The summary emphasizes national relevance: cost containment and coverage criteria for single-dose, high-cost biologics, coordination of care across hospital outpatient and specialized infusion centers, and the administrative workflow required for payers and providers. Data not available in the input will be identified within the body of the publication.

Billing Code Overview

HCPCS Level II code C9309 represents the billing descriptor Injection, onasemnogene abeparvovec-brve, per treatment. This code denotes a single administration of the gene therapy product onasemnogene abeparvovec-brve, used for disease-modifying treatment in eligible patients.

Service Type: Gene therapy injection / single-dose intravenous administration

Typical Site of Service: Hospital outpatient setting or specialized infusion center

Data not available in the input.

Clinical Context

A pediatric patient aged 6 months with genetically confirmed spinal muscular atrophy (SMA) Type 1 presents for a one-time intravenous gene replacement therapy using onasemnogene abeparvovec‑brve. Pre-infusion workflow includes verification of genetic diagnosis, baseline neurologic and respiratory assessment, review of prior immunizations and anti‑AAV9 antibody titer, baseline liver function tests and platelet count, and care coordination with pediatric neurology and infusion pharmacy. On the day of service the patient is admitted to an outpatient infusion center or pediatric hospital ambulatory infusion unit equipped for pediatric resuscitation. The multidisciplinary team includes a pediatric neurologist, pediatric nurse experienced in IV biologic administration, pharmacy staff preparing the weight‑based dose, and a caregiver present for consent and post‑infusion observation. The product, billed as C9309, is administered as a single intravenous infusion over the recommended time; vital signs and liver function are monitored per protocol during and after infusion. Post‑treatment instructions include steroid prophylaxis monitoring, scheduled laboratory follow‑up (liver enzymes, platelets), and neurology clinic follow‑up to assess motor milestones and adverse events.

Coding Specifications

Modifier	Description	When to Use
`JW`	Drug amount discarded/not administered	Use when part of the dispensed onasemnogene abeparvovec dose is discarded and documentation supports billing only for administered portion where applicable by payer rules.

Taxonomy Code	Specialty	Notes
`207RC0000X`	Pediatric Neurology	Pediatric neurologists coordinate diagnosis confirmation, eligibility, and follow‑up.
`163W00000X`	Pediatrician	Primary pediatric providers manage baseline assessments and ongoing care coordination.
`3336C0001X`	Pediatric Nurse Practitioner	Advanced practice providers perform assessment and may supervise infusion in outpatient settings.
`363L00000X`	Clinical Pharmacist	Pharmacists prepare weight‑based gene therapy dose and oversee handling and storage.
`251B00000X`	Infusion Nurse	Nurses skilled in pediatric infusion manage IV administration and monitoring.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`G12.0`	Infantile spinal muscular atrophy, type I (Werdnig‑Hoffmann disease)	Primary indication for onasemnogene abeparvovec; gene replacement aims to improve motor function and survival.
`G12.1`	Other inherited spinal muscular atrophy	Represents other genetically confirmed SMA subtypes that may be evaluated for therapy depending on age and weight criteria.
`G12.8`	Other spinal muscular atrophies and related syndromes	Used for less specific or atypical presentations within SMA spectrum where gene therapy consideration occurs.
`Z13.8`	Encounter for screening for other specified diseases and disorders	May be used for genetic screening encounters that lead to diagnosis and treatment planning for SMA.
`Z51.88`	Encounter for other specified aftercare	Used for post‑infusion follow‑up care and monitoring after administration of onasemnogene abeparvovec.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`96365`	Intravenous infusion, for therapy, prophylaxis, or diagnosis; initial, up to 1 hour	May be used to report infusion administration time components for initial infusion monitoring if payer accepts alongside the drug HCPCS billing rules.
`96366`	Each additional hour (list separately in addition to code for primary infusion)	Use when infusion monitoring extends beyond the first hour and payer allows time‑based infusion administration coding.
`96372`	Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); subcutaneous or intramuscular	Not typically used for intravenous gene therapy; may be reported for concurrent IM/SQ injections (e.g., vaccines or steroids) given the same day if separately documented.
`36415`	Collection of venous blood by venipuncture	Used for baseline and serial laboratory monitoring (liver enzymes, platelet counts) associated with onasemnogene abeparvovec administration.
`94010`	Breathing capacity test (spirometry)	Applicable when baseline or follow‑up respiratory function testing is required for clinical assessment in SMA patients.
`99354`	Prolonged evaluation and management service in the office or other outpatient setting, face-to-face, first hour (add-on)	May be used for extended face‑to‑face time for complex consent, education, or monitoring visit when documentation supports prolonged services and payer accepts add‑on coding.

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Summary & Overview