[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Spinal muscular atrophy (SMA) therapies](https://durgical.com/en/pharmacology/classes/spinal-muscular-atrophy-therapies/) › Onasemnogene abeparvovec # Onasemnogene abeparvovec ## Spinal muscular atrophy (SMA) therapies? Spinal muscular atrophy (SMA) therapies One-time intravenous gene therapy for spinal muscular atrophy in children under two. An AAV vector delivers a working SMN gene; it can injure the liver. Updated Nov 1, 2026 Also called: Onasemnogene abeparvovec-xioi ## Quick facts **Group** [Spinal muscular atrophy (SMA) therapies](https://durgical.com/en/pharmacology/classes/spinal-muscular-atrophy-therapies/) **Target** Survival motor neuron (SMN) protein, by replacement of the SMN1 gene **Used for** Spinal muscular atrophy **Key effects** Raised liver enzymes · Vomiting · Infusion reactions **Monitor** Platelet count and signs of bleeding **ATC** M09AX09 No doses: the clinician sets them by the current guideline. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## Mechanism of action Onasemnogene abeparvovec is an adeno-associated virus vector carrying a fully functional copy of the human SMN gene. After a single intravenous infusion, the vector reaches motor neurons and the new gene makes SMN protein, replacing what the mutated SMN1 genes cannot produce. With enough SMN, motor neurons survive, which improves movement, motor milestones and survival in infantile-onset SMA. - A single intravenous infusion of the viral vector - The vector delivers a working SMN gene into motor neurons - Motor neurons make their own SMN protein - Motor neurons survive: better movement and survival ## Indications - Spinal muscular atrophy (SMN1 mutations) in children less than two years old, with genetic confirmation [Spinal muscular atrophy →](https://durgical.com/en/conditions/spinal-muscular-atrophy/) ## Adverse effects ### Common - Raised liver enzymes - Vomiting - Infusion reactions: hives, itching, rash, fast heartbeat, fast breathing ### Serious (rare, important) - Acute serious liver injury (boxed warning): jaundice, abdominal pain, vomiting, drowsiness, confusion, dark urine - Low platelet count with unusual bruising or bleeding - Confusion, weakness, breathlessness, seizures or reduced urine output, which call for urgent assessment - Possible increased risk of cancer ## Contraindications - Hypersensitivity to the product or any of its components ## Key interactions **Vaccines during the corticosteroid course** Some vaccines are contraindicated at immunosuppressive steroid doses; the vaccination schedule is adjusted with the treating team. ## What is monitored - Liver function tests before the infusion and for at least three months afterwards - Platelet count and signs of bleeding - Vital signs during and after the infusion - Signs of infection, which can make adverse reactions worse ## Administration and safety - A single intravenous infusion given by a doctor or nurse in a health-care setting, with monitoring during and after. - A corticosteroid is started the day before and continued for at least a month afterwards to protect the liver. - Genetic testing confirms eligibility beforehand; age-appropriate vaccines are reviewed before treatment. - For a month after the infusion, carers wash their hands after contact with body fluids or waste and discard soiled materials in sealed bags. ## Pregnancy and breastfeeding It is given to infants and young children; pregnancy data do not apply to its use. ## Nursing care - Check baseline liver tests, platelets and kidney and heart history before the infusion. - Watch for hives, vomiting, tachycardia or fast breathing during the infusion. - Teach carers to give every corticosteroid dose and to report jaundice, dark urine, drowsiness or bruising. - Teach hand hygiene and safe disposal of nappies and soiled materials. ## Pharmacokinetics **Absorption** A single intravenous infusion; the dose is based on body weight. **Elimination** Vector shed in body fluids and waste for a period after the infusion. ## Memory aid ONASEMNOGENE: «ONe And Single: SMN Gene» — once only, liver checks and steroids around it. ## Test yourself Think of the answer, then tap the question to see it. ## What does onasemnogene abeparvovec deliver, and how? A functional copy of the human SMN gene, carried by an adeno-associated virus vector in a single intravenous infusion. ## What is the boxed warning of onasemnogene abeparvovec? Acute serious liver injury; liver function is checked before and for at least three months after. ## Why is a corticosteroid given with onasemnogene abeparvovec? To help prevent liver damage; it starts the day before the infusion and continues for at least a month. ## Which age group is onasemnogene abeparvovec approved for? Children less than two years old with SMA. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/onasemnogene-abeparvovec/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## Connections ## Related drugs 2 - [Nusinersen](https://durgical.com/en/pharmacology/nusinersen/) - [Risdiplam](https://durgical.com/en/pharmacology/risdiplam/) ## Related conditions 1 - [Spinal muscular atrophy](https://durgical.com/en/conditions/spinal-muscular-atrophy/) [← Back to the class: Spinal muscular atrophy (SMA) therapies](https://durgical.com/en/pharmacology/classes/spinal-muscular-atrophy-therapies/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Onasemnogene abeparvovec-xioi Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a626009.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [FDA approves innovative gene therapy to treat pediatric patients with spinal muscular atrophy, a rare disease and leading genetic cause of infant mortality](https://www.fda.gov/news-events/press-announcements/fda-approves-innovative-gene-therapy-treat-pediatric-patients-spinal-muscular-atrophy-rare-disease) (U.S. Food and Drug Administration, 2019); [Spinal muscular atrophy: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/spinal-muscular-atrophy/) (MedlinePlus Genetics (U.S. National Library of Medicine), 2018); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=M09AX09) (WHO Collaborating Centre for Drug Statistics Methodology, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/onasemnogene-abeparvovec/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/onasemnogene-abeparvovec/