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Page last checked: 17th March 2023
Last updated: 23rd February 2023


An interim analysis of data was published in the scientific journal, Neurology and Therapy. This aimed to present early data on the safety of risdiplam in a range of people with SMA, who had previously been enrolled in an SMA clinical trial or been treated with an approved SMA drug. Also assessed were the drug pharmacodynamics, which provided information on what the drug does to the body (e.g., whether SMN protein levels are affected).

A total of 174 participants were enrolled in the study, aged between 1 and 60 years (median of 14 years) and with a diagnosis of SMA Type 1, 2 or 3. Most participants (78%) possess three copies of the SMN2 gene. All participants included in the preliminary analysis had received daily oral doses of risdiplam for at least 1 year.

Those included in the trial belonged to one of four groups; they had either participated in the MOONFISH trial of risdiplam (13 people, 3 of which had received placebo), or had received olesoxime (71 people), nusinersen (76 people) or onasemnogene abeparvovec (14 people).

Similar to previous trial results, no safety issues with risdiplam were identified after 12 months of treatment, and there were no drug-related safety issues causing participant withdrawal from the trial.

Increased SMN protein levels in blood were identified in the treatment population, similar to previous reports from the FIREFISH and SUNFISH trials of risdiplam. After 4 weeks of treatment, risdiplam resulted in a median two-fold increase in SMN levels compared to baseline (i.e., the value recorded at the start of the study), which was largely sustained over the year treatment period.

As expected, the baseline SMN levels tended to be higher in participants with SMA Type 2 compared to SMA Type 1, and in those with more copies of SMN2. There was also a trend indicating that participants with more SMN2 copies, produced more SMN protein upon treatment.

No clear differences in SMN protein levels at baseline or after one year of risdiplam treatment were identified between participants in the four different pre-treatment groups.

JEWELFISH is still ongoing and final data from the trial will be reported in due course when participants have received risdiplam for 24 months.

9th-11th June 2021:

Preliminary findings were presented at the Cure SMA 2021 Virtual SMA Research & Clinical Care Meeting:


  • Safety of risdiplam was shown to be consistent with previous studies.
  • No treatment-related adverse events (AEs) leading to withdrawal or treatment discontinuation were observed, with some patients receiving treatment for more than three years.
  • The most common AEs in all patients were upper respiratory tract infection (17%), pyrexia (17%), headache (16%), nausea (12%), diarrhoea (11%), nasopharyngitis (10%) and vomiting (8%).
  • The most common serious AEs were pneumonia (2%) lower respiratory tract infection (2%), upper respiratory tract infection (2%) and respiratory failure (2%).

SMN levels:

All patients treated with risdiplam showed a sustained >2-fold increase in SMN protein levels when compared to the start of the trial, irrespective of previous treatment or SMA type.

Motor function:

Efficacy data indicated that people treated with risdiplam showed stabilisation in motor function after one year of treatment, as measured by change from baseline in motor function measure (MFM 32).