Treatment with risdiplam (Evrysdi®) improves and maintains motor function in patients with spinal muscular atrophy (SMA), according to new 2-year data from the phase 2 JEWELFISH trial. Moreover, the rapid increase in the survival motor neuron (SMN) protein is also maintained.

The long-term safety data from the trial is consistent with that seen in previous trials and the study dropout rates are low, the investigators reported.

JEWELFISH is the largest-ever trial conducted in previously treated SMA patients, with more than 7000 patients taking part worldwide.

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“The consistent safety profile and exploratory efficacy we have seen in the JEWELFISH study . . . reinforces Evrysdi as a meaningful treatment option across SMA populations,” said Claudia Chiriboga PhD, professor of neurology and pediatrics at the Department of Neurology at Columbia University Medical Center in New York, in a press release. “The findings add to our confidence when making treatment decisions for previously-treated patients in need.”

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A total of 174 patients with SMA type 1, 2, or 3, aged 6 months to 60 years, were enrolled in the trial. Almost half (44%) of these patients were previously treated with another disease-modifying treatment. 

After 4 weeks of treatment, risdiplam led to a 2-fold increase in median SMN protein levels, compared to baseline, irrespective of previous treatment. These levels were maintained for more than 2 years. The results also showed that the maintenance of motor function was sustained 2 years after the start of risdiplam treatment, compared to the natural history of untreated SMA patients.

The rate of adverse events, which included pyrexia, upper respiratory tract infection, headache, nasopharyngitis, diarrhea, nausea, and cough, decreased by more than half between the first and second 6-month periods of treatment. It remained stable thereafter.

The rate of serious adverse events including pneumonia, respiratory failure, respiratory distress, and lower and upper respiratory tract infections decreased throughout the 24-month period, with a total reduction of more than half by the second year of treatment.

“These important data demonstrate the safety and efficacy of Evrysdi in a broad, real-world population of people previously treated with an SMA-targeting therapy,” said Levi Garraway, MD, PhD, the chief medical officer and head of Global Product Development at Genentech, the codevelopers of the treatment.


Positive new data for Genentech’s Evrysdi in largest trial ever undertaken in patients with previously-treated spinal muscular atrophy (SMA). News release. Genentech; October 11, 2022.

A study of risdiplam (RO7034067) in adult and pediatric participants with spinal muscular atrophy (Jewelfish). US National Library of Medicine. January 26, 2017. Last updated August 3, 2022. Accessed October 17, 2022.