SMN1 and proximal spinal muscular atrophy: SUNFISH, a phase 3, randomized, double-blind, placebo-controlled study, investigates the efficacy and safety of risdiplam in type 2 and non-ambulant type 3 SMA aged 2 to 25 years.76Part 1 of the study showed that a median two-fold increase of serum SMN protein was obtained within four weeks of treatment initiation at the highest dose level.