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How effective is Evrysdi?

Medically reviewed by Carmen Fookes, BPharm. Last updated on Sep 7, 2020.

Official Answer


At least four major trials have reported that Evrysdi significantly improves survival motor neuron (SMN) protein levels in children and young 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. The following is a summary of available trials.

The SUNFISH trial is an ongoing study investigating Evrysdi in 231 people aged 2-25 years with Type 2 or 3 spinal muscular atrophy (SMA). Results so far have reported:

  • Significantly improved motor function after 24 months of treatment compared to natural history data
  • Treatment with Evrysdi leads to rapid and sustained increases in SMN protein levels
  • On average, people experienced a two-fold increase in blood SMN protein levels after four weeks, which was sustained for at least 24 months.

FIREFISH, a study investigating 17 children with infantile-onset SMA reported:

  • 41% who were given the recommended dosage of 0.2mg/kg/day were able to sit independently for ≥ 5 seconds after 12 months of treatment. This represented a meaningful deviation from the natural history of untreated infantile-onset SMA because typically, these patients would not be expected to attain the ability to sit independently
  • After 12 months of treatment, 90% were alive without permanent ventilation (and reached 15 months of age or older).
  • After a minimum of 23 months of treatment, 81% were alive without permanent ventilation and had reached an age of 28 months or older
  • Without Evrysdi, no more than 25% of these patients would have been expected to survive without permanent ventilation beyond 14 months of age. Evrysdi allowed patients to reach a median age of 32 months; range 28 to 45 months.

A study investigating 51 patients with late-onset SMA (SMA Type 2 or Type 3) reported that:

  • There was a 1.36 change in baseline MFM32 score after 12 months of Evrysdi treatment; people assigned to placebo reported a -0.19 ( a worsening) in their baseline score
  • 38.3% of patients taking Evrysdi reported a change from baseline MFM32 total score of 3 or more after 12 months of treatment.


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