187 SUNFISH Part 2: 24-month efficacy of risdiplam compared with external control comparators

Risdiplam (EVRYSDI®) is an oral survival of motor neuron 2 (SMN2) premRNA splicing modifier approved by the EMA and MHRA for the treatment of patients aged ≥2 months, with a clinical diagnosis of Type 1, 2 or 3 spinal muscular atrophy (SMA) or 1–4 copies of SMN2. SUNFISH ( NCT02908685 ) is a two-part, randomised, placebo-controlled, double-blind study in a broad population of patients aged 2–25 years at enrolment, with Type 2/3 SMA. Part 2 assesses the efficacy and safety of the Part 1-selected dose of risdiplam versus placebo in Type 2 and nonambulant Type 3 SMA. Participants were treated with risdiplam or placebo for 12 months; all participants then received risdiplam until Month 24, when patients were offered the opportunity to enter the open-label extension. The primary outcome of Part 2 – change from baseline to Month 12 in the 32-item Motor Function Measure total score in patients treated with risdiplam (n=120) versus placebo (n=60) – was met. Here we present analyses to compare 24-month data from the risdiplam arm with an external comparator dataset con- taining data from participants in the NatHis-SMA study ( NCT02391831 ) and the placebo arm of a Phase 2 study of olesoxime in patients with SMA ( NCT01302600 ).