Zolgensma: A One-Time Gene Therapy for Spinal Muscle Atrophy
Spinal muscular atrophy (SMA) is a rare but serious genetic disorder that affects the nerve cells controlling certain muscles. As a result, muscles gradually weaken over time, leading to difficulty with movements such as sitting, breathing, or even swallowing – especially in infants and young children, though the condition can also occur in adults.1
Babies born with Type 1 SMA – the most common and severe form – often face significant difficulties right from birth. Without treatment, they typically cannot sit or stand on their own, and many do not survive beyond the age of 2.1
What is Zolgensma?
Zolgensma is a breakthrough gene therapy designed for babies and toddlers under 2 years old with SMA. Unlike other treatments that need to be given regularly, Zolgensma is administered as a one-time intravenous (IV) infusion.2
This single-dose therapy targets the root cause of SMA, offering children a real chance at improved movement, easier breathing and longer, better-quality life.2
How does Zolgensma work?
In healthy children, a gene called SMN1 produces a vital protein needed to keep muscles strong and functioning. In children with SMA, this gene is missing or not working correctly. As a result, their bodies can’t produce enough of the protein needed for muscles to work properly.3
Zolgensma contains onasemnogene abeparvovec-xioi, a gene therapy that delivers a working copy of the SMN1 gene using a harmless, lab-made viral vector called adeno-associated vector 9 (AAV9). Once inside the body, the SMN1 gene delivered enters the motor nerve cells and begins working inside them. It provides instructions to produce the SMN protein. This protein helps protect and support the nerve cells that control muscles, which can improve muscle strength and function.2
How is Zolgensma administered?
Zolgensma is given through a one-time IV infusion – a slow drip through a vein, usually lasting about an hour. The dosage is calculated based on the child’s weight, and the procedure is done in a hospital under close observation.4,5
Doctors usually prescribe a steroid medicine (like prednisolone) before and after the infusion to protect the liver and manage the body’s immune response.4
What are the tests needed before the treatment?
To make sure Zolgensma in a safe for the child, the doctor runs some important blood tests, including4
- Liver function tests (to check how well the liver is working)
- Platelet count (to check for bleeding risks)
- Troponin levels (to monitor heart health)
- AAV9 antibody test (to see if the child has immunity to the carrier vector)
If the child has a fever, cold or infection, the doctor will delay treatment until the child has fully recovered, as giving Zolgensma while the child is unwell could increase the risk of serious side effects.4
It is also important to inform the doctor if the child has recently received any live vaccines, as these could interfere with how the therapy works.4
What to expect after treatment?
After receiving Zolgensma, the child will need regular check-ups for a few months. These include blood tests to track5
- Liver health
- Platelet levels
- Heart enzyme (troponin) levels
These check-ups help doctors spot and manage any side effects early.
What are the possible side effects?
Most children tolerate Zolgensma well, especially with the help of steroids. However, some children may experience the following side effects6:
- Fever or feeling unwell: Some children may develop a mild fever or seem generally unwell shortly after the infusion. This is common and usually goes away on its own within a few days.
- Low platelet count: Platelets are tiny cells in the blood that help stop bleeding. In some cases, the number of platelets may drop in the first week after treatment. This typically corrects itself naturally and rarely requires any medical intervention.
- Changes in liver function: While there may be some temporary changes in liver function, these typically don’t cause any noticeable symptoms. Doctors can detect this through routine blood tests and monitor it over time.
- Slight increase in troponin levels: Troponin is a protein that helps assess heart function. In a few cases, blood tests show a mild rise in troponin, but in clinical trials, no children treated with Zolgensma showed actual heart problems.
- Very rare risk of thrombotic microangiopathy (TMA): In extremely rare instances, a condition called TMA has been reported. This affects the kidneys and causes issues with blood clotting. The doctor will closely monitor for any signs to ensure early detection and treatment if needed.
How does Zolgensma compare with other SMA treatments?
Zolgensma stands apart from other SMA treatments in several important ways. It is given as a single IV infusion, unlike other options that require ongoing treatment. By contrast, Spinraza is administered through repeated spinal injections, and Evrysdi must be taken as a daily oral liquid.2
The way these treatments work is also different. Zolgensma is the only therapy that replaces the missing SMN1 gene, which is the root cause of SMA.2 Spinraza and Evrysdi, on the other hand, work by enhancing the backup SMN2 gene, helping the body produce some of the missing protein – but not by fixing the actual genetic defect.7
When it comes to how long the treatment lasts, Zolgensma is given just once, whereas Spinraza and Evrysdi must be continued for life. As for who can receive these therapies, Zolgensma is approved for children under the age of 2, whereas Spinraza is approved for patients of all ages, and Evrysdi can be given to children as young as 2 years.8
Is Zolgensma available or accessible in India?
Although Zolgensma is not yet commercially available in India, patients can access Zolgensma through the Named Patient Program (NPP). This program enables access to globally approved treatments that are not yet locally available in India, ensuring patients receive high-quality medications through legal, regulated channels. For families battling rare and life-threatening conditions like SMA, this opens the door to better treatment options and renewed hope.9
How to access Zolgensma through the NPP in India?
To apply for Zolgensma under the NPP, families will need to complete several steps. These include documentation and regulatory approvals required to legally import and administer the therapy:
- A doctor’s prescription and a detailed letter from a paediatric neurologist confirming your child’s diagnosis of SMA.
- Genetic test reports indicating the absence or mutation of the SMN1 gene.
- Mandatory blood test results, especially those needed before treatment – such as liver function, antibody screening (AAV9), and platelet count.
- An import license from the Central Drugs Standard Control Organization.
- Proof of payment or financial assistance, which may come from charitable foundations, crowdfunding platforms, non-governmental organizations, or government schemes.
Who can help you navigate the process?
Specialized facilitators like Rx4U India are well-equipped to guide families through every stage of accessing Zolgensma under the NPP. They work closely with doctors, government authorities, and the manufacturer (Novartis Gene Therapies) to ensure that everything proceeds smoothly and legally.
These experts help by
- Gathering and submitting all required medical documents and test reports
- Coordinating with the manufacturer for supply and necessary approvals
- Overseeing the legal import and ensuring safe transportation of the drug
- Arranging for administration at an authorized hospital or treatment centre
- Choosing a trusted partner like Rx4U can make a big difference – reducing delays, simplifying paperwork, and helping your child receive treatment safely and on time.
Final takeaway:
- Zolgensma is a one-time gene therapy for babies and toddlers under 2 years old with SMA.
- It replaces the missing gene responsible for muscle strength and movement.
- Children need careful monitoring before and after treatment, especially for liver health.
- Side effects are generally manageable and often temporary.
- Families in India can access Zolgensma through the Named Patient Program.
Frequently asked questions:
- Can Zolgensma cure SMA?
Answer: While not a cure, Zolgensma can significantly improve survival and motor outcomes by addressing the genetic root cause.1,2
- Is Zolgensma safe?
Answer: Yes, when administered with proper precautions and monitoring, Zolgensma has a favourable safety profile.2
- Is there an age limit for Zolgensma?
Answer: It is approved for children under 2 years of age and should ideally be administered as early as possible.2
- Can Indian patients get Zolgensma?
Answer: Yes, it is accessible through the Named Patient Program with proper documentation and medical eligibility.9
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.
References:
- Spine muscular atrophy. Cleveland clinic. Updated June 6, 2024. Accessed June 10, 2025. https://my.clevelandclinic.org/health/diseases/14505-spinal-muscular-atrophy-sma
- 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).
- Spinal muscular atrophy. NIH. Accessed June 10, 2025. https://www.ninds.nih.gov/health-information/disorders/spinal-muscular-atrophy
- Prescribing information. Novartis Gene Therapies, Inc; 2025.
- European Medicines Agency. Updated May 6, 2025. Accessed June 10, 2025. https://www.ema.europa.eu/en/medicines/human/EPAR/zolgensma
- Zolgensma for spinal muscular atrophy. NHS. Accessed June 10, 2025. https://library.sheffieldchildrens.nhs.uk/zolgensma-for-spinal-muscular-atrophy/
- Zhu X. Comparison of nusinersen and Evrysdi in the treatment of spinal muscular atrophy. E3S Web of Conferences. 2021;271:03035. doi:10.1051/e3sconf/202127103035
- Yeo CJ, Simmons Z, De Vivo DC, Darras BT. Ethical perspectives on treatment options with spinal muscular atrophy patients. Ann Neurol. 2022;91(3):305-316.
- Patil S. Early access programs: Benefits, challenges, and key considerations for successful implementation. Perspect Clin Res. 2016;7(1):4-8. doi:10.4103/2229-3485.173779
