A Phase 3 Study Evaluating Safety and Effects of Salanersen After Onasemnogene Abeparvovec Treatment in Infants With Spinal Muscular Atrophy

What this Trial Is About

Researchers are evaluating the safety and effects of salanersen BIIB115 in babies with spinal muscular atrophy SMA who have already been treated with onasemnogene abeparvovec OA. SMA is caused by changes in the SMN1 gene that reduce the SMN protein needed for proper muscle and nerve function. Salanersen aims to increase SMN protein production by acting on the SMN2 gene, potentially improving outcomes when given after OA treatment. This is a phase 3, randomized, double-blind study focused on infants diagnosed genetically with SMA and treated presymptomatically with OA. Participants will be randomly assigned to receive either salanersen or a sham procedure during Part A, which lasts one year. Salanersen is given as an injection into the fluid surrounding the spinal cord via lumbar puncture. Part A includes six clinic visits and two phone calls. In Part B, lasting up to four years, all participants receive yearly doses of salanersen with up to twelve clinic visits and fourteen phone calls. The study evaluates safety, motor skill development, symptom progression, and drug levels in blood and spinal fluid. Throughout the study, participants will undergo various assessments, including motor milestone tests like the WHO motor milestones and HINE Section 2. Researchers will monitor adverse events, motor function changes, biomarker levels, and survival outcomes. The total participation time can be up to five and a half years, with regular clinic visits and phone contacts to track health and treatment effects.

A Study to Learn About the Safety and Effects of Salanersen (BIIB115) When Given to Babies With Spinal Muscular Atrophy (SMA) Who Were Previously Treated With Onasemnogene Abeparvovec