A Study for Participants With Spinal Muscular Atrophy (SMA) Who Previously Participated in Nusinersen (ISIS 396443) Investigational Studies

The WHO motor milestones are a set of six milestones in motor development, all of which would be expected to be attained by 24 months of age in healthy children. The individual milestones are: sitting without support, standing with assistance, hands and knees crawling, walking with assistance, standing alone and walking alone. Mean of number of new milestones achieved was calculated and reported in this outcome measure.

HINE is evaluated in infants between 2-24 months of age. It's a simple, standardized instrument including 26 items assessing different aspects of neurological examinations, such as cranial nerves, posture, movements, tone, and reflexes. In this study, Module 2 of HINE (HINE-2) was assessed, which evaluates 8 developmental milestones (head control, sitting, voluntary grasp, ability to kick, rolling, crawling, standing, and walking) scored on a 3, 4, or 5-point scale, with 0 indicating inability to perform task and score of 2, 3, or 4 indicating full milestone development. Total score is calculated by summing item scores to give maximum possible score of 26. Higher score indicates good neurological function.

Permanent ventilation was defined as tracheostomy or >=16 hours of ventilator support per day continuously for >21 days in the absence of an acute reversible event.

Permanent ventilation was defined as tracheostomy or >=16 hours of ventilator support per day continuously for >21 days in the absence of an acute reversible event.

The CHOP INTEND test is designed to evaluate the motor skills of infants with significant motor weakness, including infants with SMA. Participants who are ≥2 years will be continued to be assessed until a CHOP INTEND maximum score of 64 is achieved. It includes 16 items structured to move from easiest to hardest with the grading including gravity eliminated (lower scores) to antigravity movements (higher scores). All item scores range from 0 (worst) to 4 (best). Total scores range from 0 to 64, with higher scores indicating better movement functioning.

The HFMSE consists of 33 scored activities used to assess motor function in children with SMA. Participants were asked to do a specific activity (such as rolling) and they were then graded on the quality and execution of that movement on a scale of 0=being unable, 1=performed with some compensation, and 2=unaided. The overall score is the sum of the scores for all activities with a maximum achievable score of 66. Higher scores indicate increased motor function.

RULM Test is used in participants with SMA to assess upper limb functional ability items and has total of 20 items with an entry item that serves as functional class identification and does not contribute to total score. Remaining 19 scorable items reflect different functional domains and graded on 3-point system with score of 0 (unable), 1 (able, with modification), and 2 (able, no difficulty). There is only 1 item that is scored as a can/cannot score, with 1 as the highest score. Scorable items are summed for total score (0-37), higher scores indicating increased upper limb function. Positive change from baseline indicates improvement.

The 6MWT measures the distance an individual can walk over a total of six minutes on a hard, flat surface. The goal is for the individual to walk as far as possible in six minutes.

Contracture assessment is performed to assess the motor performance in SMA. The number of participants who experienced at least one contracture at any location and severe contractures in any of the five locations (hip flexors, knee flexors, ankle planter flexors, elbow flexors, forearm flexors) are reported in this outcome measure.

CMAP is an electrophysiological technique that can be used to determine the approximate number of motor neurons in a muscle or group of muscles. Peroneal amplitude (PA) and ulnar amplitude (UA) data is reported in this OM. Score <0 indicated worse response and >0 indicated better response than the normal matched population. Score change <0 indicated worsening and >0 indicated improvement as compared to baseline.

Participants were analyzed for change in growth parameter of body length to evaluate clinical efficacy. The body length was calculated using either WHO or Centers for Disease Control and Prevention (CDC) scales. The CDC scale allows to calculate the body length up to 20 years, while the WHO scale allows to calculate it only up to 10 years.

Participants were analyzed for change in growth parameter of weight to evaluate clinical efficacy. The weight was calculated using either WHO or CDC scales. The CDC scale allows to calculate the weight up to 20 years, while the WHO scale allows to calculate it only up to 10 years.

Participants who were below the age of 36 months were analyzed for change in growth parameter of weight for age to evaluate clinical efficacy. The weight for age percentile was calculated using either WHO or CDC scales. The CDC scale allows to calculate the weight for age percentile up to 20 years, while the WHO scale allows to calculate it only up to 10 years.

CMAP is an electrophysiological technique that can be used to determine the approximate number of motor neurons in a muscle or group of muscles. A participant was defined as a responder if they had a peroneal amplitude ≥1 mV at last visit (including the amplitude ≥1 mV at baseline and also demonstrated as such at last visit).

Motor milestones were measured based on WHO criteria. The WHO motor milestones are a set of six milestones in motor development, all of which would be expected to be attained by 24 months of age in healthy children. The individual milestones are: sitting without support (SWS), standing with assistance (SWA), hands and knees crawling (HKC), and walking alone (WA).

Motor milestones were measured based on WHO criteria. The WHO motor milestones are a set of six milestones in motor development, all of which would be expected to be attained by 24 months of age in healthy children. The individual milestones are: SWS, SWA, HKC, WWA, WA and standing alone (SA). SA and WWA were assessed in this outcome measure.

Total number of hospitalizations is total number of serious events that occurred during study for all participants under each group. For a participant with multiple SAEs which started at the same date and led to hospitalization, it is counted as one hospitalization.

Total number of hospitalizations is total number of serious events that occurred during study for all participants under each group. For a participant with multiple SAEs which started at the same date and led to hospitalization, it is counted as one hospitalization.

Cobb angle is a measurement of the degree of side-to-side spinal curvature used to define scoliosis.

Items on the PedsQL generic core scale are reverse scored and transformed to a 0-100 scale. The PedsQL parent (P) and self (S) reported questionnaire was collected for participants from 2 to 25 years of age. Four dimensions were collected: Physical, Emotional, Social and School functioning and each item was scored on a 5 point ordinal scale. 0 (never) =100, 1 (almost never) = 75, 2 (sometimes)= 50, 3 (often) = 25, 4 (almost always) = 0. A total score was calculated as the sum of all the items over the number of items answered on all the scales. If more than 50% of items or more were missing, the scale score was not computed. Higher scores indicated better health related quality of life.

The ACEND is a questionnaire that includes a total of seven domains assessing physical impact (including feeding/grooming/dressing, sitting/play, transfers, and mobility) and general caregiver impact (including time, emotion, and finance) and each domain comprises several items. The total score (TS) for each domain will be calculated on a scale of 0 to 100. Higher scores indicate a greater impact on the caregiver.

Survival rate was defined as the percentage of participants alive during the study and was estimated from the Kaplan Meier (KM) curve for time to death.