Adverse events were analyzed for all participants in Parts A & B combined as one group for this outcome measure. An AE was defined as any untoward medical occurrence that develops or worsens in severity during the conduct of a clinical study and does not necessarily have a causal relationship to the study drug. Incudes clinically significant changes such as changes in vital signs or lab values. Relationship of AE to treatment was determined by the Investigator. Serious AEs include death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability or incapacity, a congenital anomaly or birth defect, or an important medical event that jeopardized the participant and required medical intervention to prevent the previously listed serious outcomes. A summary of other non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

Safety analysis set included all participants who received at least 1 dose of study drug.

Adverse events were analyzed for Part B for this outcome measure. An AE was defined as any untoward medical occurrence that develops or worsens in severity during the conduct of a clinical study and does not necessarily have a causal relationship to the study drug. Incudes clinically significant changes such as changes in vital signs or lab values. Relationship of AE to treatment was determined by the Investigator. Serious AEs include death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability or incapacity, a congenital anomaly or birth defect, or an important medical event that jeopardized the participant and required medical intervention to prevent the previously listed serious outcomes. A summary of other non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

Population includes all participants who completed Period I, were randomized in Period II, and who were administered any study drug in the randomized withdrawal period, Part B (Period II).

Parents were asked to rate their child's behaviors in past 2 weeks on a 4-point Likert scale from "not at all" to "much or most of the time." It contains 2 subscales (emotional problems and functional problem). Total score: sum of 2 subscales, ranging from 0 to 51, with higher score indicating more depression-related behaviors.

Safety analysis set included all participants who received at least 1 dose of study drug. Here, 'number analyzed' signifies participants evaluable for specified categories.

CDI-2 self-report: 28-item questionnaire assessing depressive symptoms in children 7 to 17 years of age with basic reading and comprehension skills. Children were asked to choose 1 of 3 statements that most closely aligns with their feelings in past 2 weeks. It contains 6 subscales (emotional problem, negative mood/physical symptoms, negative self-esteem, functional problems, ineffectiveness, interpersonal problems). Total score: sum of all subscales scores, ranging from 0 to 56, with higher score indicating greater depression severity.CDI-2 parent: 17-item questionnaire administered to parents to assess depression-related behaviors observed in their children.

Safety analysis set included all participants who received at least 1 dose of study drug. Here, 'number analyzed' signifies participants evaluable for specified categories.

Parents were asked to rate their child's behaviors in past 2 weeks on a 4-point Likert scale from "not at all" to "much or most of the time." It contains 2 subscales (emotional problems and functional problem). Total score: sum of 2 subscales, ranging from 0 to 51, with higher score indicating more depression-related behaviors.

Population includes all participants who completed Period I, were randomized in Period II, and who were administered any study drug in the randomized withdrawal period, Part B (Period II). Here, 'number analyzed' signifies participants evaluable for specified categories.

CDI-2 self-report: 28-item questionnaire assessing depressive symptoms in children 7 to 17 years of age with basic reading and comprehension skills. Children were asked to choose 1 of 3 statements that most closely aligns with their feelings in past 2 weeks. It contains 6 subscales (emotional problem, negative mood/physical symptoms, negative self-esteem, functional problems, ineffectiveness, interpersonal problems). Total score: sum of all subscales scores, ranging from 0 to 56, with higher score indicating greater depression severity.CDI-2 parent: 17-item questionnaire administered to parents to assess depression-related behaviors observed in their children.

Population includes all participants who completed Period I, were randomized in Period II, and who were administered any study drug in the randomized withdrawal period, Part B (Period II). Here, 'number analyzed' signifies participants evaluable for specified categories.

C-SSRS included responses for Suicidal Ideation or Suicidal Behavior in following 10 categories: 1 = Wish to be dead; 2 = Non-specific active suicidal thoughts; 3 = Active suicidal ideation with any methods (not plan) without intent to act; 4 = Active suicidal ideation with some intent to act, without specific plan; 5 = Active suicidal ideation with specific plan and intent; 6 = Preparatory acts or behavior; 7 = Aborted attempt; 8 = Interrupted attempt; 9 = Non-fatal suicide attempt; and 10 = Completed suicide. Number of participants with any suicidal ideation or suicidal behavior are reported. Any Suicidal ideation or Suicidal Behavior events reported as TEAEs along with all other reported TEAEs are included in the AE module.

Safety analysis set included all participants who received at least 1 dose of study drug. Here, 'number analyzed' signifies participants evaluable at specified timepoints.

C-SSRS included responses for Suicidal Ideation or Suicidal Behavior in following 10 categories: 1 = Wish to be dead; 2 = Non-specific active suicidal thoughts; 3 = Active suicidal ideation with any methods (not plan) without intent to act; 4 = Active suicidal ideation with some intent to act, without specific plan; 5 = Active suicidal ideation with specific plan and intent; 6 = Preparatory acts or behavior; 7 = Aborted attempt; 8 = Interrupted attempt; 9 = Non-fatal suicide attempt; and 10 = Completed suicide. Number of participants with any suicidal ideation or suicidal behavior are reported. Any Suicidal ideation or Suicidal Behavior events reported as TEAEs along with all other reported TEAEs are included in the AE module.

Population includes all participants who completed Period I, were randomized in Period II, and who were administered any study drug in the randomized withdrawal period, Part B (Period II). Here, 'number analyzed' signifies participants evaluable at specified timepoints.

YGTSS rating scale is a semi-structured clinician rating instrument that provides an evaluation of the number, frequency, intensity, complexity, and interference of motor and phonic tics. YGTSS is composed of 11 items: 5 items for motor tic severity, 5 items for vocal tic severity, and 1 item for impairment. Each item for motor tic severity and vocal is rated on a 6-point scale (0 for none to 5 to severe). MTSS is the sum of the 5 items for motor tic severity and VTSS is the sum of the 5 items for vocal tic severity. TTS is the sum of MTSS and VTSS, ranges from 0 (none/absent) to 50 (severe). Higher scores indicate greater severity/worse outcome. Baseline is defined as the last measurement on or prior to the first dose of the open-label study medication.

ITT analysis set includes all participants enrolled in part I. Here, 'number analyzed' signifies participants evaluable at specified time points.

The TS-CGI scale is a 7-point Likert scale that allows the clinician to use all available information to assess the impact of tics on the participant's quality of life. The TS-CGI is rated as follows: 1 (normal or no tics at all), 2 (borderline), 3 (mild), 4 (moderate), 5 (marked), 6 (severe), and 7 (extreme, incapacitating tics). Lower scores indicate better quality of life. Baseline is defined as the last measurement on or prior to the first dose of the open-label study medication.

Data were not collected during Part B (Period II). ITT analysis set includes all participants enrolled in part I. Here, 'number analyzed' signifies participants evaluable at specified time points.

The TS-PGII is a single-item questionnaire that asks the participant to assess the degree of impact due to current tics (How much do your current tics disrupt things in your life?). The TS-PGII uses a 5-point scale, ranging from not at all (1) to very much (5), to assess overall response to therapy. Baseline is defined as the last measurement on or prior to the first dose of the open-label study medication.

Data were not collected during Part B (Period II). ITT analysis set includes all participants enrolled in part I. Here, 'number analyzed' signifies participants evaluable at specified time points.

C&A-GTS-QOL is a 27-item questionnaire that asks participant to assess the extent to which their quality of life is impacted by their symptoms. C&A-GTS-QOL contains 6 subscales (cognitive, coprophenomena, psychological, physical, obsessive-compulsive, and ADL) and uses a 5-point Likert scale ranging from no problem to extreme problem. Following 3 questions from 27-item questionnaire were assessed in ADL C&A-GTS-QOL subscale: Question 2 (Had difficulty with school or sport activities?), 24 (Felt you needed more help or support from other people?), and 26 (Had difficulty going out with other people?). Total score of ADL subscale ranged from 0 (no problem) to 12 (extreme problem). Lower score indicated better quality of life. Baseline is defined as the last measurement on or prior to the first dose of the open-label study medication.

Data were not collected during Part B (Period II). ITT analysis set includes all participants enrolled in part I. Here, 'number analyzed' signifies participants evaluable at specified time points.

YGTSS rating scale is a semi-structured clinician rating instrument that provides an evaluation of the number, frequency, intensity, complexity, and interference of motor and phonic tics. YGTSS is composed of 11 items: 5 items for motor tic severity, 5 items for vocal tic severity, and 1 item for impairment. Each item for motor tic severity and vocal is rated on a 6-point scale (0 for none to 5 to severe). MTSS is the sum of the 5 items for motor tic severity and VTSS is the sum of the 5 items for vocal tic severity. TTS is the sum of MTSS and VTSS, ranges from 0 (none/absent) to 50 (severe). Higher scores indicate greater severity/worse outcome. The model is an ANCOVA model that includes fixed effects for treatment group. The randomized withdrawal baseline TTS and age group at baseline (2 levels: 6-11 years, 12-18 years) are included as covariates.

All participants that completed Part 1, were randomized to Part 2, received at least one dose of study drug in the randomized withdrawal period and have an YGTSS TTS at both week 28 visit (randomized withdrawal baseline) and week 30 visit, and have a ≥25% reduction in the TTS from baseline in the parent study to week 28.