An AE was any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not.

An AE was any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Participants who discontinued treatment due to AEs are reported here.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not.

Tanner staging of sexual development is a scale used to assess physical maturation as children transition through adolescence into adulthood. Scale defines physical development based on the following characteristics: pubic hair, penis, and testes development in boys; and pubic hair and breast development in girls. It consists of 5 stages, Stage I (prepubertal) to Stage V (mature adult). Participants under 9 years at screening began Tanner staging assessments at 1st visit following their 9th birthday. Tanner data are presented in three categories: Normal (expected stage of puberty based on participant's age at post-baseline visit), Delayed (pubertal development is behind expectations for age at post-baseline visit), & Missing (participant did not attend scheduled visit). Tanner staging assessments were scheduled for participants aged 9-17 years but were also conducted in some older participants, up to age 22. Shift in puberty status from baseline to each week has been represented here.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not. Overall number analyzed is the number of participants with data available for analysis. No participants from the AVXS-101 arm were assessed for Tanner staging since all participants in this arm were under 9 years of age.

Neurological examination was performed by asking questions to the participants and/or their caregiver, as well as observing the participants' behavior in general and while performing certain tasks. Questions and tasks were adapted to the age and motor ability of the participant. For very young participants, observing reaction to a sound, speech development, shifting attention to a newly introduced toy, observing the participant interact with the parent/caregiver & for older participants examination of social interaction (school, friends, activities, job as appropriate), memory (e.g., with short word recall), reasoning & language, drawing, etc. Participants with neurological conditions besides those expected with SMA and those expected with SMA are reported.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not.

C-SSRS was used to assess the lifetime suicidality of a participant (baseline) as well as any new instances of suicidality (since last visit). The interview prompts recollection of suicidal ideation (SI), including the intensity of the ideation, behavior and attempts with actual/potential lethality. A modified and reduced version (pediatric version) was used for children (aged 6-11 years). Categories have binary responses (yes/no) & include: Wish to be Dead; Non-specific Active Suicidal Thoughts; Active SI with Any Methods (Not Plan) without Intent to Act; Active SI with Some Intent to Act, without Specific Plan; Active SI with Specific Plan & Intent, Preparatory Acts & Behavior; Aborted Attempt; Interrupted Attempt; Actual Attempt (non-fatal); Completed Suicide. SI or behavior is indicated by a "yes" answer to any of the listed categories. A score of 0 is assigned if no suicide risk is present. A score of 1 or higher indicates SI or behavior.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not. Participants with SI, suicidal behavior, and self-injurious behavior without suicidal intent are reported for this outcome measure. Overall number analyzed are the number of participants with at least one post-baseline assessment.

Weight was measured at baseline, Weeks 65, 91, and every 13 weeks thereafter for participants 2-17 years and at every visit for participants <2 years. Per protocol, height was not measured at Day 7, Weeks 8, 17, 35, and thus not collected for all participants. No participants in the RO6885247 arm attended the Weeks 65, 169, 195, and 247 visit; none in the AVXS-101 arm attended the Week 247 visit. Symptom-directed height/weight assessments were done at clinically indicated visits as needed.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not. Overall number analyzed is the number of participants with data available for analysis. Number analyzed is the number of participants with data available for analysis at the specified timepoint.

Height of all participants able to stand was measured while standing using a stadiometer, with at least 3 independent measurements, which were averaged. Participants unable to stand during the measurement, height was derived from measurement of ulna length. For very young children, height was measured with child in a lying position using an inflexible length board with fixed headboard & movable footboard. Height was measured: baseline, Weeks 13,39,52,78 & 104 for participants 2-17 years; Weeks 52 & 104 for >17 years & every visit for participants <2 years. After Week 104, measurements occurred every 26 weeks. Per protocol, height was not measured at Weeks 2,4,17,26,35,43,61,65,87,91,96,117,143,169,195,221 &247 & thus not collected for all participants. No participants <17 years in RO6885247, Olesoxime, or AVXS-101 arms attended the Week 260 visit & no participants in RO6885247 arm attended Week 39. Symptom-directed height assessments were done at clinically indicated visits as needed.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not. Overall number analyzed is the number of participants with data available for analysis. Number analyzed is the number of participants with data available for analysis at the specified timepoint.

Head circumference for participants aged < 5 years was measured to the nearest 0.1 cm using a flexible, non-stretchable tape. Head circumference was measured around the widest part of the head from the most prominent point on the back of the head (occiput) to the most prominent part of the forehead between the eyebrows. The measurement was repeated three times, and the largest measurement was recorded. Head circumference was assessed for participants < 5 years of age. Since all participants in the RO6885247 and Olesoxime arms were > 5 years, data were not collected for these arms. Head circumference was not collected at Weeks 35 and 61 (AVXS-101 arm) and Weeks 87, 182, and 208 (Nusinersen arm) because the protocol only required this measurement for participants < 5 years of age. At these timepoints, neither of the participants < 5 years attended the visit, and other participants may have been > 5 years of age.

SE population included all participants who received at least one dose of risdiplam, whether prematurely withdrawn from the study or not. Overall number analyzed is the number of participants with data available for analysis. Number analyzed is the number of participants with data available for analysis at the specified timepoint.

As pre-specified in the protocol, the PK data were not to be compared between participants who received different prior treatments (RO6885247, nusinersen, olesoxime and AVXS-101) received before entering this study, but to analyze the PK parameters of risdiplam. Hence, PK data have been presented in a single arm group irrespective of prior therapies received by the participants in previous studies.

PK population included all participants with at least one timepoint with a measurable drug concentration. Overall number analyzed is the number of participants with data available for analysis.

As pre-specified in the protocol, the PK data were not to be compared between participants who received different prior treatments (RO6885247, nusinersen, olesoxime and AVXS-101) received before entering this study, but to analyze the PK parameters of risdiplam. Hence, PK data have been presented in a single arm group irrespective of prior therapies received by the participants in previous studies.

PK population included all participants with at least one timepoint with a measurable drug concentration. Overall number analyzed is the number of participants with data available for analysis.

As pre-specified in the protocol, the PK data were not to be compared between participants who received different prior treatments (RO6885247, nusinersen, olesoxime and AVXS-101) received before entering this study, but to analyze the PK parameters of risdiplam. Hence, PK data have been presented in a single arm group irrespective of prior therapies received by the participants in previous studies.

PK population included all participants with at least one timepoint with a measurable drug concentration. Overall number analyzed is the number of participants with data available for analysis.

SMA is caused by a homozygous deletion or mutation of the SMN 1 gene, which encodes SMN, an essential protein expressed in both neuronal and non-neuronal cells. In humans, there are two SMN genes, the SMN1 gene and its paralog SMN2. Risdiplam directly targets the underlying molecular deficiency of the disease and promotes the inclusion of exon 7 to generate full-length SMN2 mRNA, which therefore increases the production of functional SMN protein. As pre-specified in the protocol, the PD data were not to be compared between participants who received different prior treatments, but to analyze the PD parameters of risdiplam. Hence, PD data have been presented in a single arm group irrespective of prior therapies received by the participants in previous studies.

Pharmacodynamic (PD) population included all participants with at least one timepoint with a measurable PD marker. Overall number analyzed is the number of participants with data available for analysis.