A Study of Risdiplam (RO7034067) in Adult and Pediatric Participants With Spinal Muscular Atrophy

Inclusion Criteria:

1. Confirmed diagnosis of 5q-autosomal recessive SMA
2. Previous enrollment in Study BP29420 (Moonfish) with the splicing modifier RO6885247 or previous treatment with any of the following: 1.) Nusinersen (defined as having received >= 4 doses of nusinersen, provided that the last dose was received >= 90 days prior to screening) or 2.) Olesoxime (provided that the last dose was received <= 12 months and >= 90 days prior to screening) or 3.) AVXS-101 (provided that the time of treatment was >= 12 months prior to screening)
3. Adequately recovered from any acute illness at the time of screening and considered well enough to participate in the opinion of the Investigator
4. For women of childbearing potential: negative blood pregnancy test at screening, agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating eggs for at least 28 days after the final dose of study drug
5. For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures and agreement to refrain from donating sperm
6. For participants aged 2 years or younger at screening: 1.) Parent or caregiver of participant is willing to consider nasogastric, naso-jejunal or gastrostomy tube placement, as recommended by the Investigator, during the study to maintain safe hydration, nutrition and treatment delivery; 2.) Parent or caregiver of participant is willing to consider the use of non-invasive ventilation, as recommended by the Investigator during the study

Exclusion Criteria:

1. Inability to meet study requirements
2. Concomitant participation in any investigational drug or device study
3. With the exception of studies of olesoxime, AVXS-101, or nusinersen: Previous participation in any investigational drug or device study within 90 days prior to screening, or 5 half-lives of the drug, whichever is longer
4. Any history of gene or cell therapy, with the exception of AVXS-101
5. Unstable gastrointestinal, renal, hepatic, endocrine, or cardiovascular system diseases as considered to be clinically significant by the Investigator
6. Inadequate venous or capillary blood access for the study procedures, in the opinion of the Investigator
7. For patients aged < 2 years, hospitalization for a pulmonary event within 2 months prior to screening and pulmonary function not fully recovered at the time of screening
8. Lactating women
9. Suspicion of regular consumption of drugs of abuse
10. For adults and adolescents only, positive urine test for drugs of abuse or alcohol at screening or Day -1 visit
11. Presence of clinically significant electrocardiogram (ECG) abnormalities before study drug administration from average of triplicate measurement or cardiovascular disease
12. History of malignancy if not considered cured
13. For participants aged > 6 years, significant risk for suicidal behavior, in the opinion of the Investigator as assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS)
14. Any major illness within one month before the screening examination or any febrile illness within one week prior to screening and up to first dose administration
15. Recently initiated treatment for spinal muscular atrophy (within <6 weeks prior to enrollment) with oral salbutamol or another beta 2-adrenergic agonist taken orally
16. Any prior use of chloroquine, hydroxychloroquine, retigabin, vigabatrin or thioridazine, is not allowed
17. Ascertained or presumptive hypersensitivity (e.g., anaphylactic reaction) to risdiplam or to the constituents of its formulation
18. Concomitant disease or condition that could interfere with, or treatment of which might interfere with, the conduct of the study, or that would, in the opinion of the Investigator, pose an unacceptable risk to the participant in this study
19. Recent history (less than one year) of ophthalmological diseases
20. Any prior use of an inhibitor or inducer of FMO1 or FMO3 taken within 2 weeks (or within 5 elimination half-lives, whichever is longer) prior to dosing