Newborns treated with Evrysdi sit unassisted after 1 year
80% of pre-symptomatic SMA babies able to sit at least five seconds
After a year of treatment with oral Evrysdi (risdiplam), 80% of babies with pre-symptomatic spinal muscular atrophy (SMA) were able to sit without support for at least five seconds.
The findings met the primary outcome measure of RAINBOWFISH, a Phase 2 clinical trial (NCT03779334) evaluating the therapy in babies, ages birth to 6 weeks. All the babies could swallow and feed orally, and none required permanent breathing support, according to one of Evrysdi’s developers, Genentech, in a company press release.
“Evrysdi is the only noninvasive SMA treatment and can be used within hours of birth, potentially allowing these babies to sit, stand and walk, similar to healthy individuals,” said Levi Garraway, MD, PhD, Genentech’s chief medical officer. “Evrysdi has now demonstrated its safety and efficacy in babies, children and adults, and these compelling data continue to reinforce our confidence in this treatment.’’
SMA is caused by mutations in the SMN1 gene, which encodes for SMN, a protein needed for motor neurons. These are nerve cells that control voluntary movement. The SMN2 gene also encodes for SMN, but little protein gets made due to differences in its sequence. Fewer copies of SMN2 are associated with more severe disease.
Evrysdi is an oral liquid therapy given once daily. It was first approved for people with SMA, ages 2 months and older.
Developed by Roche and its subsidiary Genentech, alongside PTC Therapeutics and the SMA Foundation, it enhances the activity of SMN2 to increase SMN production. Because studies show the loss of motor neurons occurs before the onset of symptoms, early treatment is critical for better outcomes.
Effects of Evrysdi after a year
Interim data from RAINBOWFISH supported its recent approval in the U.S. and Europe for those younger than 2 months. The data showed the first five babies treated for at least a year were alive, had retained the ability to swallow, could sit independently, and most reached major motor milestones such as crawling, standing, and walking.
The open-label RAINBOWFISH enrolled 26 babies with two or more copies of the SMN2 gene, with genetically confirmed SMA but without evident disease symptoms.
Among the primary efficacy population, which included five babies with 2 SMN2 copies, 80% could sit without support for at least five seconds after a year of Evrysdi, as measured by the Bayley Scales of Infant and Toddler Development.
Of the study’s 26 babies, 81% were able to sit independently for 30 seconds. This included all the patients with low pre-treatment compound muscle action potential (CMAP) amplitudes, an indicator of motor nerve health. This means they had evidence of motor neuron dysfunction. Most of the infants were standing and walking, according to Genentech.
As an exploratory outcome, RAINBOWFISH was the first trial to show that a year on Evrysdi sustained cognitive skills typical of normal child development, as assessed using the standard Bayley Scales of Infant and Toddler Development (BSID).
Evrysdi’s safety profile in this patient population has been consistent with findings in older patients. Commonly reported side effects include cough, fever, rash, vomiting, constipation, diarrhea, and lung and/or nose infections. Most side effects were not considered related to treatment and there were no withdrawals or treatment discontinuations and no deaths in RAINBOWFISH.
“These data reinforce the value of beginning treatment for SMA before symptoms appear, with the goal of preserving motor neurons while they are still abundant,” said Richard Finkel, MD, RAINBOWFISH’s principal investigator and director of the experimental neuroscience program at St. Jude Children’s Research Hospital, in Tennesee. “Coupled with widespread newborn screening programs, early treatment could counteract the effects of the disease to give babies with pre-symptomatic SMA the best possible start in life.”
The new data were presented at the 28th World Muscle Society (WMS) Congress, Oct. 3-7, in South Carolina.
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