How does Evrysdi work for SMA?

Medically reviewed by Carmen Pope, BPharm. Last updated on Feb 20, 2025.

Official answer

by Drugs.com

Evrysdi (risdiplam) works by targeting the SMN2 gene (survival motor neuron gene 2), causing it to make more functional SMN protein. This increases SMN protein levels throughout the central nervous system and body, helping to improve motor nerve and muscle function in children and adults with spinal muscular atrophy (SMA). It must be taken for a person's lifetime.

Evrysdi was approved by the FDA on August 7, 2020 and is available as a liquid that is given by mouth or through a gastrostomy tube (g-tube) once a day after a meal. It is also now available as a 5 mg tablet (approved February 12, 2025), that can be swallowed whole or dispersed in filtered (unchlorinated) water.

Evrysdi may be used to treat all types of SMA in adults, children, and newborns. A label extension for Evrysdi in May, 2022 to include pre-symptomatic infants aged under 2 months (or newborns) allows healthcare providers to intervene as early as possible in treating babies with SMA.

What is spinal muscular atrophy (SMA)?

SMA is a rare genetic disease that is caused by a mutation in the survival motor neuron gene 1 (SMN1). This gene produces a protein that is critical to the function of the nerves that control our muscles. Without this protein, motor nerve cells die, muscles become progressively weaker and waste away (atrophy), leaving children and adults unable to properly eat or breathe and robbing them of their physical strength and their ability to walk. However, it does not affect a person’s ability to think, learn, and build relationships with others. SMA is the number one genetic cause of death for infants, with many dying at a young age from respiratory failure.

All children and adults with SMA have at least one “backup gene,” known as SMN2. This gene has a similar structure to SMN1, but only around 10% of the SMN protein it produces is fully functional.

SMA can affect any race or gender and about 1 in every 50 Americans is a genetic carrier. SMA affects approximately 1 in 11,000 births and there are four primary types of SMA: 1, 2, 3, and 4.

References

Drug Trials Snapshots: EVRYSDI US Food and Drug Administration https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshots-evrysdi
Evrysdi Cure SMA Genentech https://www.curesma.org/evrysdi/
Evrysdi Package Insert. https://www.gene.com/download/pdf/evrysdi_patientinfo.pdf
Evrysdi Prescribing Information. https://www.gene.com/download/pdf/evrysdi_prescribing.pdf

Evrysdi vs Spinraza: How do they compare?

Evrysdi (risdiplam) and Spinraza (nusinersen) work in different ways to increase the level of functional SMN (survival of motor neuron) protein in people with spinal muscular atrophy (SMA). A key difference between the two drugs is that Evrysdi is taken orally, whereas Spinraza needs to be given via intrathecal injection. Continue reading

How effective is Evrysdi?

Several major trials have reported that Evrysdi significantly improves survival motor neuron (SMN) protein levels in newborns, children, and adults with SMA, allowing an increase in muscle strength and the achievement of milestones, such as being able to sit independently for 5 or more seconds at a time. Continue reading

Does Evrysdi cure spinal muscular atrophy (SMA)?

Evrysdi does not cure spinal muscular atrophy (SMA), it just replaces a protein that is low or missing in children or adults with the condition, improving muscle strength and allowing some relief from some of the symptoms of SMA. Evrysdi must be taken for a person’s lifetime; if Evrysdi is stopped the newborn, child, or adult’s SMA symptoms will progressively worsen at a faster rate. Continue reading

Drug information

Evrysdi Information for Consumers
Evrysdi prescribing info & package insert (for Health Professionals)
Side Effects of Evrysdi (detailed)

Related support groups

Evrysdi (5 questions, 3 members)
Spinal Muscular Atrophy (10 questions, 3 members)

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