Zolgensma: Benefits, Dosage, Side Effects & Safety Tips
What Is Zolgensma?
Zolgensma is a special gene therapy used to treat children under 2 years old who are diagnosed with spinal muscular atrophy (SMA). SMA is a rare but serious genetic condition that causes weakness and wasting of the muscles. Children with SMA are born with mutations that affect a gene called SMN1, which leads to low levels of an important protein called SMN protein.1,2
Understanding the Active Ingredient: Onasemnogene Abeparvovec-Xioi
The main ingredient in Zolgensma is called onasemnogene abeparvovec-xioi. This is a special type of medicine known as a gene therapy. It uses a harmless virus (AAV9) to carry a working copy of the human SMN1 gene into the patient’s body. Once inside, the healthy gene helps make the SMN protein that is missing in SMA patients.2
How Zolgensma Works Inside the Body
Zolgensma has a single-dose, free-of-preservative, sterile, IV infusion of AAV9 that crosses the blood-brain barrier. Zolgensma works by letting the body create the SMN protein, which is important for muscle strength and movement. The treatment puts the gene into motor nerve cells, so these cells can start making the SMN protein right away. This process helps slow or stop the loss of muscle strength that happens in SMA.2
Dosage Guidelines and Administration Details
Zolgensma is a one-time treatment given through a slow intravenous (IV) infusion. The dosage is based on the weight of the child, with a standard dose being 1.1 × 10¹⁴ vector genomes per kilogram of body weight. The infusion usually takes about 60 minutes, and it must be given in a hospital or medical setting under professional supervision.3
Precautions Before Starting Zolgensma
Before administering ZOLGENSMA, patient should be clinically stable in terms of overall baseline health to reduce the risk of a serious systemic immune response. This includes being well-hydrated, nutritionally supported, and free from infections.
If an infection is present, the infusion should be postponed until the infection has resolved and the patient shows no signs or symptoms of illness at the time of treatment. In addition, liver function should be assessed prior to infusion.3
Laboratory tests such as creatinine levels and a complete blood count, including hemoglobin and platelet count, should be obtained. Baseline testing for anti-AAV9 antibodies must also be performed.
A daily dose of oral prednisolone (or a similar steroid) at 1 mg per kg of body weight is started exactly one day before the ZOLGENSMA infusion and continued for 30 days in total.3
What to Expect During and After Administration
ZOLGENSMA must be given slowly over 60 minutes. It should never be given as an intravenous push or bolus. Liver function are monitored regularly through both clinical exams and lab tests. At the end of the 30-day steroid treatment, liver health should be checked again by examining the patient and testing levels of ALT, AST, total bilirubin, prothrombin time, and INR. 3
If liver test results worsen or if the patient shows signs of illness like vomiting or overall health decline, they’re monitored and assessed closely. If all liver-related test results are within normal range, then tapering of the corticosteroid dose is done slowly over the next 28 days. Steroids should not be stopped suddenly. 3
If liver function tests are still abnormal, corticosteroids are continued until test values return to normal. If the patient cannot tolerate oral steroids, switch to intravenous steroids can be made, as needed. 3
Common Side Effects of Zolgensma
The most common side effects reported with ZOLGENSMA (occurring in 5% or more patients) were elevated liver enzymes (aminotransferases) and vomiting.3
Other common side effects include injury to the liver (hepatotoxicity), low levels of blood platelets (thrombocytopenia), raised levels of troponin (a measure which indicates damage to the heart muscle) and fever.1
Serious Warnings and Monitoring Requirements
Zolgensma can cause serious liver-related side effects, including acute liver injury, liver failure, and elevated liver enzymes (ALT, AST), and some fatal cases have been reported. To reduce the risk of liver injury, systemic corticosteroids must be started before and continued after infusion. Liver function should be checked before treatment and monitored for at least 3 months post-infusion, with weekly testing for the first month and biweekly for the next, especially during the steroid tapering period. 3
Zolgensma can also trigger a strong immune response, so it should only be given when the child is stable, without infections, and fully vaccinated as per schedule. Thrombocytopenia and, in rare cases, thrombotic microangiopathy (TMA) have also been reported within weeks of treatment. Patients must be monitored closely for unusual bruising, high blood pressure, or reduced urine output. 3
Some children may have infusion-related reactions during or after receiving Zolgensma. These can include rash, hives, vomiting, breathing problems, or changes in heart rate or blood pressure. Doctors will monitor the child closely during and after the infusion. If a reaction happens, the infusion will be paused, and supportive care will be given as needed. Once the child is stable, the doctor may decide to restart the infusion. Although extremely rare, there is a theoretical risk of tumor formation due to the AAV vector used in the therapy. So, any post-treatment tumors must be reported.3
Safety Profile and Long-Term Use Considerations
Zolgensma provides sustained, durable benefits in children with spinal muscular atrophy, with a favorable safety profile over time. Children treated after SMA symptom onset maintained all previously achieved motor milestones up to 7.5 years after a one-time intravenous infusion. Some also gained new abilities like standing with assistance. All participants were alive, feeding orally, and many no longer required daily ventilatory support. No serious treatment-related adverse events or new safety concerns were reported.4
Overall, the benefits of Zolgensma usually outweigh the risks for eligible children with SMA.1
How Zolgensma Is Different from Other Gene-Based Therapies
Zolgensma stands out from other SMA treatments because it is a one-time gene therapy that delivers a working copy of the SMN1 gene directly into the body using a viral vector. Unlike nusinersen, which has long been the standard treatment in the US and needs ongoing dosing, Zolgensma is designed to provide long-term benefit with a single infusion. This reduces the treatment burden and may lead to better long-term outcomes, especially when given early. Its approach targets the root genetic cause of SMA, aiming for sustained improvement in motor function and survival. This makes it different in both its delivery method and its potential for lifelong impact.5
Accessing Zolgensma in India Through the Named Patient Program
Zolgensma is not generally available in India as a regular prescription drug. It can be accessed through a "Named Patient Program" (NPP), which lets patients receive the drug with special permission for rare or life-threatening diseases. The drug is very expensive, and the cost may be supported by special access or charitable programs. You can work with a licensed importer or access partner like Rx4U for ease of processing.
Documentation and Process for NPP Access
The treating doctor must apply for permission to import the drug for a specific patient. Documents needed include medical reports, SMA diagnosis confirmation, and requests for import approval to government agencies and customs authorities. Approval can take several weeks. Once granted, licensed facilitators help with importing the medicine and managing customs clearance.
Role of Licensed Facilitators in Importing Zolgensma
Only approved facilitators or hospitals with the right permissions can import and administer Zolgensma in India. They work with doctors, the government, and shipping agents to make sure the medicine reaches the patient safely and legally.
Summary: Key Points to Know Before Considering Zolgensma1-3
- Zolgensma is a one-time gene therapy for children under 2 years with SMA.
- It can provide long-lasting improvement in muscle strength and movement.
- Liver health must be watched closely before and after treatment.
- Talk to a qualified doctor to see if Zolgensma is right for your child and learn about ways to access it through special programs in India.
Frequently Asked Questions (FAQs) About Zolgensma
Q: How long does Zolgensma last?
A: It is a one-time treatment, but its effects can last for many years, with children showing benefit for up to 7.5 years.4
Q: What are the main risks?
A: The main risks are liver injury and problems with blood clotting and platelets, so close monitoring is required.3
Q: Can my child get Zolgensma?
A: If your doctor recommends it, you can apply for it under the Named Patient Program with guidance from specialists and facilitators.17,18
Note:
The information provided is for education purpose only and is subjected to prescribing information of the drug and the guidance of your treating physician. Always consult your health care provider before making any medical decision for starting your treatment.
Disclaimer:
Rx4U procures prescribed medicines directly from manufacturers or authorized distributors. It does not claim ownership of any trademarks and complies with the provisions of the Trademark Act, 1999, particularly Sections 30 and 30(1) concerning ‘Fair Use’. It solely facilitates access to new launches through named patient import.
AMA Style References
- European Medicines Agency (EMA). Zolgensma. Available at: https://www.ema.europa.eu/en/medicines/human/EPAR/zolgensma
- Ogbonmide T, Rathore R, Rangrej SB, et al. Gene Therapy for Spinal Muscular Atrophy (SMA): A Review of Current Challenges and Safety Considerations for Onasemnogene Abeparvovec (Zolgensma). Cureus. 2023;15(3):e36197. Published 2023 Mar 15. doi:10.7759/cureus.36197
- S. Food and Drug Administration. ZOLGENSMA (onasemnogene abeparvovec-xioi) [package insert]. Feb 2025. Accessed July 24, 2025.
- Novartis shares Zolgensma® long-term data demonstrating sustained durability up to 7.5 years post-dosing with 100% achievement of all assessed milestones in children treated prior to SMA symptom onset [news release]. Novartis; June 13, 2024. Accessed July 24, 2025.
- Naveed A, Calderon H. Onasemnogene Abeparvovec (AVXS-101) for the Treatment of Spinal Muscular Atrophy. J Pediatr Pharmacol Ther. 2021;26(5):437-444. doi:10.5863/1551-6776-26.5.437
