Majority of newborn babies with spinal muscular atrophy (SMA) treated with Evrysdi (risdiplam) are able to sit independently after 1 year of treatment – Roche

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.The data were presented at the 28th World Muscle Society (WMS) Congress, 3-7 October 2023.

“Evrysdi is the only non-invasive SMA treatment and can be used within hours of birth, potentially allowing these babies to sit, stand and walk, similar to healthy individuals,” said Levi Garraway, M.D., Ph. D., Roche’s Chief Medical Officer and Head of Global Product Development. “Evrysdi has now demonstrated its safety and efficacy in babies, children and adults and these compelling data continue to reinforce our confidence in this treatment.’’

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 greater than 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 ( less than 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.

“These data reinforce the value of beginning treatment for SMA before symptoms appear, with the goal of preserving motor neurons while they are still abundant,” said Richard Finkel, M.D., RAINBOWFISH Principal Investigator and Director of the Experimental Neuroscience Program at St. Jude Children’s Research Hospital. “Coupled with widespread newborn screening programs, early treatment could counteract the effects of the disease to give babies with pre-symptomatic SMA the best possible start in life.”

Roche is also investigating Evrysdi in combination with an anti-myostatin molecule, which is designed to promote muscle growth, among SMA patients 2-10 years of age in the Phase II/III MANATEE trial.

Evrysdi is currently being evaluated in five multicentre trials in people with SMA : i.FIREFISH (NCT02913482) – an open-label, two-part pivotal clinical trial in infants with Type 1 SMA. The study met its primary endpoint. ii. SUNFISH (NCT02908685) – a two-part, double-blind, placebo-controlled pivotal study in people aged 2-25 years with Types 2 or 3 SMA. The study met its primary endpoint. iii JEWELFISH (NCT03032172) – an open-label exploratory trial designed to assess the safety, tolerability, pharmacokinetics and pharmacodynamics in people with SMA aged 6 months to 60 years who received other investigational or approved SMA therapies for at least 90 days prior to receiving Evrysdi. The study has completed recruitment (n=174). iv. RAINBOWFISH (NCT03779334) – an open-label, single-arm, multicentre study, investigating the efficacy, safety, pharmacokinetics, and pharmacodynamics of Evrysdi in babies (n=26), from birth to six weeks of age (at first dose) with genetically diagnosed SMA who are not yet presenting with symptoms. The study is fully enrolled. v. MANATEE (NCT05115110) – a global phase II/III clinical study to evaluate the safety and efficacy of GYM329 (RG6237), an anti-myostatin molecule targeting muscle growth, in combination with Evrysdi for the treatment of SMA in patients 2-10 years of age. The FDA Office of Orphan Products Development granted GYM329 Orphan Drug Designation for the treatment of patients with SMA in December 2021. The study is currently recruiting.