Open-Label Phase 3 Study Evaluating Salanersen BIIB115 for Spinal Muscular Atrophy in People Aged 15 to 60 Years Including Both New and Risdiplam-Treated Participants

What this Trial Is About

Researchers are evaluating the effects and safety of BIIB115, also called salanersen, in people aged 15 to 60 years with spinal muscular atrophy SMA. This condition is caused by changes in the SMN1 gene, leading to low levels of SMN protein, which affects motor neurons and muscles. Salanersen aims to increase SMN protein production from the SMN2 gene. The study includes two groups those new to SMA treatment and those previously treated with risdiplam, who must stop risdiplam during the study. Participants will receive salanersen by intrathecal injection into the fluid around the brain and spinal cord once every 12 months, for a total of five doses over the study period. This open-label study involves 17 visits and 9 phone calls spanning up to 61 months. Both treatment-nave and risdiplam-treated groups will receive the same dosing schedule. During the study, researchers will assess changes in motor function using tests like the Hammersmith Functional Motor Scale - Expanded HFMSE and other measures of nerve and muscle performance. They will monitor safety, including adverse events, and measure salanersen levels in cerebrospinal fluid and blood. Participants will be closely followed to understand how salanersen affects their ability to perform daily activities over the course of the trial.

A Study to Learn About Salanersen's (BIIB115) Effects on Movement and Its Safety in Participants Aged 15 to 60 Years With Spinal Muscular Atrophy (SMA) Who Are Either New to SMA Treatment or Were Previously Treated With Risdiplam