A Study Evaluating the Effectiveness and Safety of Risdiplam Administered as an Early Intervention in Pediatric Participants With Spinal Muscular Atrophy After Gene Therapy (HINALEA 1)

Inclusion Criteria: <2 years of age at the time of informed consent Confirmed diagnosis of 5q-autosomal recessive SMA Confirmed presence of two SMN2 gene copies Administration of onasemnogene abeparvovec pre-symptomatically or post-symptomatically Has received onasemnogene abeparvovec for SMA no less than 3 months, but not more than 7 months, prior to enrollment Has, in the opinion of the investigator, not experienced clinically significant decline in function from the time of onasemnogene abeparvovec administration Exclusion Criteria: Treatment with investigational therapy prior to initiation of study treatment Any unresolved standard-of-care laboratory abnormalities per the onasemnogene abeparvovec prescribing information Concomitant or previous administration of a SMN2-targeting antisense oligonucleotide or SMN2 splicing modifier either in a clinical study or as part of medical care Requiring invasive ventilation or tracheostomy Requiring awake non-invasive ventilation or with awake hypoxemia (SaO2 <95%) with or without ventilator support Presence of feeding tube and an OrSAT score of 0 Hospitalization for pulmonary event within the last 2 months, or any planned hospitalization at the time of screening Any major illness requiring hospitalization within 1 month before the screening examination or any febrile illness within 1 week prior to screening and up to first dose administration.