Background: SMA affects individuals with a broad age range and spectrum of disease severity. Risdiplam (EVRYSDI®) is a centrally and peripherally distributed, oral SMN2 pre-mRNA splicing modifier. Methods: SUNFISH is a multicenter, two-part, randomized, placebo-controlled, double-blind study in patients with Types 2/3 SMA. Part 1 assessed the safety, tolerability and pharmacokinetics/pharmacodynamics of different risdiplam dose levels in patients with Types 2/3 SMA. Part 2 assessed the efficacy and safety of the selected dose of risdiplam versus placebo in Type 2 and non-ambulant Type 3 SMA. In Part 2, participants were treated with risdiplam or placebo for 12 months, then received risdiplam in a blinded manner until month 24. At month 24, patients were offered the opportunity to enter the open-label extension phase. Results: Change from baseline in MFM32 total score (Part 2- primary endpoint) in patients treated with risdiplam versus placebo was met at month 12. These increases in motor function were sustained in the second and third year after risdiplam treatment. Here we present 4-year efficacy and safety data from SUNFISH. Conclusions: SUNFISH is ongoing and will provide further long-term efficacy and safety data of risdiplam in a broad population of individuals with SMA.