Study of Salanersen BIIB115 Safety and Effects on Movement in Babies with Genetically Diagnosed Spinal Muscular Atrophy Before Symptoms Appear

What this Trial Is About

Researchers are evaluating the effects and safety of salanersen BIIB115 in babies genetically diagnosed with spinal muscular atrophy SMA who have not yet shown symptoms. SMA is caused by changes in the SMN1 gene that reduce a protein essential for motor neuron and muscle function. Salanersen aims to boost production of this protein by helping the related SMN2 gene. The study includes babies with either 2 or 3 copies of the SMN2 gene, where more copies are linked to milder SMA. Participants will receive salanersen through intrathecal injections into the fluid around the brain and spinal cord. The study has two parts Part 1 lasts up to 25 months with two doses given about 12 months apart, and Part 2 lasts up to 36 months with up to three doses also spaced 12 months apart. All participants receive salanersen openly, meaning they know they are receiving the study drug. During Part 1, participants will have up to 11 clinic visits and 3 phone calls, while Part 2 includes up to 7 clinic visits and 12 phone calls. Participants will be involved in regular assessments including motor milestone tests such as the World Health Organization motor milestones, and neurological exams. Researchers will monitor how many babies achieve key motor milestones like sitting or walking independently at specific ages. The study also measures salanersen levels in cerebrospinal fluid and blood, tracks adverse events, and evaluates long-term motor function and safety. The total participation may last several years with ongoing clinic visits and phone contacts for monitoring.

A Study to Learn About Salanersen's (BIIB115) Effects on Movement and Its Safety When Given Before Symptoms Appear in Babies With Genetically Diagnosed Spinal Muscular Atrophy (SMA)