Myostatin is a negative regulator of muscle growth. Blocking myostatin activity has been shown to increase muscle size and function. Taldefgrobep alfa directly blocks myostatin activity and was well tolerated in other clinical studies. In combination with medications that increase the amount of SMN protein in the body, taldefgrobep alfa has the potential to further improve motor function and clinical measures for people living with SMA.
This trial will study the efficacy and safety of taldefgrobep alfa as an adjunctive therapy for participants who are already taking a stable dose of nusinersen or risdiplam or have a history of onasemnogene abeparvovec-xioi, compared to placebo.