How effective is Evrysdi?

Several major trials have reported that Evrysdi significantly improves survival motor neuron (SMN) protein levels in newborns, 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. 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.

The RAINBOWFISH study in newborns reported pre-symptomatic babies with SMA treated with Evrysdi achieved key milestones, such as sitting and standing, with half walking after 12 months of treatment. All infants were alive at 12 months without permanent ventilation.

Other trials

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

• Increases in motor function are sustained at three years while adverse events decreased over the same period
• A marked improvement in, or stabilization of, motor function after two years compared to an untreated external control group
• Significantly improved motor function after 24 months of treatment compared to natural history data
• 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.