The importance of early diagnosis and treatment in SMA

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Gene illustrationTreatment for spinal muscular atrophy (SMA) has undergone a major paradigm shift. Previously, management focused on supportive care; today, with disease-modifying treatment options, patients demonstrate significant improvement over the natural history.1,2

Without treatment, SMA Type 1 has historically been a leading genetic cause of infant death, with a life expectancy of less than 2 years. Initiating treatment early—even before the appearance of clinical signs—may lead to better patient outcomes, as SMA is progressive and loss of motor neurons is irreversible.1,2

Delayed diagnosis and treatment allow the disease to progress irreversibly. With timely treatment, patient outcomes can be drastically different from the natural history.1,2

After diagnosis, immediate treatment is recommended

For patients with up to 4 copies of the SMN2 gene, immediate treatment is recommended by SMA experts. Delivering treatment presymptomatically, or before significant motor weakness or loss occurs, may lead to better patient outcomes.1

Presymptomatic treatment with gene therapy

ZOLGENSMA® (onasemnogene abeparvovec-xioi) is a gene therapy for the treatment of patients with SMA who are less than 2 years of age. ZOLGENSMA has a Boxed Warning for Acute Live Failure and Acute Serious Liver Injury; please continue reading for Important Safety Information and please see the accompanying Full Prescribing Information.

The SPR1NT clinical trial is a completed, open-label study of one-time dose ZOLGENSMA. The trial enrolled 2 different cohorts of presymptomatic patients—those with 2 copies of the SMN2 gene (n=14), and those with 3 copies of SMN2 (n=15) who all met the inclusion criteria.4

Patients in SPR1NT were assessed for motor milestones, nutritional and respiratory function, and gross motor function.4

See the results from presymptomatic treatment with gene therapy at

Important Safety Information

BOXED WARNING: Acute Serious Liver Injury and Acute Liver Failure

Acute serious liver injury, acute liver failure, and elevated aminotransferases can occur with ZOLGENSMA. Patients with preexisting liver impairment may be at higher risk. Prior to infusion, assess liver function of all patients by clinical examination and laboratory testing (e.g., hepatic aminotransferases [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)], total bilirubin, and prothrombin time). Administer a systemic corticosteroid to all patients before and after ZOLGENSMA infusion. Continue to monitor liver function for at least 3 months after infusion.



Transient decreases in platelet counts, some of which met the criteria for thrombocytopenia, were typically observed within the first two weeks after ZOLGENSMA infusion. Monitor platelet counts before ZOLGENSMA infusion and on a regular basis for at least 3 months afterwards.

Thrombotic Microangiopathy

Cases of thrombotic microangiopathy (TMA) were reported approximately 1 week after ZOLGENSMA infusion. Obtain baseline creatinine and complete blood count before ZOLGENSMA infusion. Following infusion, monitor for thrombocytopenia as well as other signs and symptoms of TMA. Consult a pediatric hematologist and/or pediatric nephrologist immediately to manage if clinically indicated.

Elevated Troponin-I

Increases in cardiac troponin-I levels were observed following ZOLGENSMA infusion. Monitor troponin-I before ZOLGENSMA infusion and on a regular basis for at least 3 months afterwards.


The most commonly observed adverse reactions (incidence ≥5%) in clinical studies were elevated aminotransferases and vomiting.


ZOLGENSMA, suspension for intravenous infusion, is an adeno-associated virus vector-based gene therapy indicated for the treatment of pediatric patients less than 2 years of age with spinal muscular atrophy (SMA) with bi-allelic mutations in the survival motor neuron 1 (SMN1) gene.

Limitations of Use

The safety and effectiveness of repeat administration or the use in patients with advanced SMA (e.g., complete paralysis of limbs, permanent ventilator dependence) has not been evaluated with ZOLGENSMA.

Please click here for Full Prescribing Information for ZOLGENSMA.

References: 1. Glascock J, Sampson J, Haidet-Phillips A, et al. Treatment algorithm for infants diagnosed with spinal muscular atrophy through newborn screening. J Neuromuscul Dis. 2018;5(2):145-158.            2. Schorling DC, Pechmann A, Kirschner J. Advances in treatment of spinal muscular atrophy—new phenotypes, new challenges, new implications for care. J Neuromuscul Dis. 2020;7(1):1-13. 3. Glascock J, Sampson J, Connolly AM, et al. Revised recommendations for the treatment of infants diagnosed with spinal muscular atrophy via newborn screening who have 4 copies of SMN2. J Neuromuscul Dis. 2020;7:97-100. 4. Novartis Gene Therapies, Inc. Pre-symptomatic study of intravenous onasemnogene abeparvovec-xioi in spinal muscular atrophy (SMA) for patients with multiple copies of SMN2 (SPR1NT). identifier: NCT03505099. Updated September 7, 2022. Accessed October 3, 2022.

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