BIIB115

A Study to Learn About the Safety of BIIB115 Injections and How BIIB115 is Processed in the Bodies of Healthy Adult Male Volunteers and of Pediatric Participants With Spinal Muscular Atrophy Who Previously Took Onasemnogene Abeparvovec

A Randomized, Blinded, Placebo-Controlled, Phase 1 Single Ascending Dose Study in Healthy Adult Male Volunteers and an Open-Label Multiple Ascending Dose Study with Long-Term Extension in Pediatric SMA Participants Previously Treated with Onasemnogene Abeparvovec (Zolgensma™) to Evaluate the Safety, Tolerability, and Pharmacokinetics of BIIB115.

An Open-Label, Phase 3 Study to Evaluate the Efficacy and Safety of Salanersen (BIIB115) in Participants Aged 15-60 Years With Spinal Muscular Atrophy Who Are Either Treatment-Naïve or Have Previously Been Treated With Risdiplam

A Phase 3, Randomized, Double-Blinded Study to Evaluate the Safety and Efficacy of Salanersen (BIIB115) After Onasemnogene Abeparvovec Treatment in Infants with Genetically Diagnosed Spinal Muscular Atrophy