A Phase 3, Randomized, Double-Blind, Sham-Procedure Controlled Study to Assess the Clinical Efficacy and Safety of ISIS 396443 Administered Intrathecally in Patients With Infantile-onset Spinal Muscular Atrophy

The primary objective of the study is to examine the clinical efficacy of nusinersen (ISIS 396443) administered intrathecally (IT) to participants with infantile-onset with infantile-onset spinal muscular atrophy (SMA). The secondary objective of the study is to examine the safety and tolerability of nusinersen administered intrathecally to participants with infantile-onset SMA.