Roche presented positive results from the primary analysis of the ongoing Rainbowfish study assessing the efficacy and safety of Evrysdi (risdiplam) in babies with pre symptomatic SMA (n=26), aged from birth to six weeks.
Article continues below
The data were presented at the 28th World Muscle Society (WMS) Congress, 3 to 7 October 2023.
Clinical studies show that the loss of motor neurons may begin before symptoms start so initiating treatment early is critical for better outcomes.
The Rainbowfish study included babies with two or more copies of the SMN2 gene. Generally, the lower the number, the more severe the disease.
The study met its primary endpoint with 80% of the primary efficacy population (n=5) sitting without support for at least five seconds after 1 year of Evrysdi treatment, assessed by Bayley Scales of Infant and Toddler Development, third edition (BSID-III).
The primary efficacy population included babies with two SMN2 copies and a CMAP amplitude of ≥1.5 mV at baseline. CMAP amplitude measures the muscle response to a stimulus, and a low score correlates with symptom onset in SMA patients and worse functional outcomes.
Of the 26 babies in the study, 81% could sit independently for 30 seconds, including all patients with low CMAP amplitude at baseline (<1.5 mV) and the majority were standing and walking. Without treatment, children with Type 1 SMA would never be expected to sit.
Rainbowfish was the first trial to assess cognition with a standardised scale (BSID) as an exploratory endpoint and results showed cognitive skills typical of normal child development after 1 year of Evrysdi treatment, assessed by BSID-III.
Adverse events (AEs) were more reflective of the age of the babies than underlying SMA. The majority of AEs were not considered treatment related, and there were no deaths or AEs leading to withdrawal or treatment discontinuation.
The most common AEs were teething, COVID-19, pyrexia, gastroenteritis, eczema and constipation. The AEs observed in the Rainbowfish primary analysis are generally consistent with those AEs seen in other Evrysdi trials in SMA.
Roche is also investigating Evrysdi in combination with an anti myostatin molecule, which is designed to promote muscle growth, among SMA patients 2 to 10 years of age in the Phase 2/3 MANATEE trial. ■