P.51 Real-world experience after one year treating SMA children with risdiplam

Abstract

Risdiplam (Evrysdi®), available in France since 2020, showed to be effective and safe in clinical trials but data in real-world conditions are scarce. The aim of this study is to describe our experience with Risdiplam in SMA children, focusing on safety and functional aspects. All patients followed at our center and treated with risdiplam from November 2020 to April 2022 were included. Data were collected through the French national registry (launched in January 2020) and medical records. 28 patients were included (4 SMA1; 21 SMA2, 3 SMA3) with a median age of 12.6 years (4-20 y). At baseline, 95% had ventilatory support (22 NIV; 2 tracheostomy) and 18 had spinal surgery. 20 patients were previously treated with nusinersen. All patients were alive at the end of the follow-up period. Two patients stopped risdiplam, due to dizziness or asthenia and switched back to nusinersen (3 and 6 months after starting treatment). The remaining 26 showed good tolerability, with a median follow up of 11 months. 15 patients were followed for at least 1 year. No loss of acquisition was observed and motor improvements were reported in 53.5% of series. 6 patients had a total MFM of at least 30% at baseline, which was stable or improved after 1 year. 7 patients improved mandibular mobility. A 3 y.o SMA1 child, who had lost swallowing ability while treated with nusinersen for 18 months, improved speech and was able to swallow after one year on risdiplam. Most frequent side effects were headache, nausea, abdominal pain and diarrhea. Three patients reported photosensitivity with normal ophthalmologic assessments. Preliminary descriptive results showed good tolerance in most children and no impairments on risdiplam. Interestingly, recovery of swallowing function was observed in a young child treated previously by nusinersen, suggesting the interest of risdiplam in this population. While nusinersen was not sufficient to maintain bulbar function, it seemed to prevent complete degeneration of brainstem motor neurons. Updated data will be provided at the congress, including detailed motor, respiratory and bulbar function.