Trial Outcomes & Findings for Alternatives for Reducing Chorea in Huntington Disease (NCT NCT01897896)

Last Updated: 2021-11-09

Results Overview

An adverse event (AE) was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Severe AE=inability to carry out usual activities. Drug-related TEAEs: TEAEs with possible, probable, definite, or missing relationship to study drug. Serious AEs: death, a life-threatening AE, 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 participant and required medical intervention to prevent 1 of the outcomes listed in this definition. TEAEs: events that 1) began after treatment with study drug in current study and that were not present at baseline or 2) if present at baseline, had worsened in severity. Any TEAEs included both serious and non-serious TEAEs. A summary of other non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

119 participants

Primary outcome timeframe

Baseline to follow-up visit (up to approximately 3 years 9 months)

Results posted on

2021-11-09

Participant Flow

Participant milestones

Participant milestones
Measure	Rollover Cohort: SD-809 ER Participants who completed study SD-809-C-15 (either placebo or SD-809 group \[NCT01795859\], including 1-week washout period and Week 13 evaluation), received 6 milligrams(mg) SD-809 ER tablet once daily as starting dose in this study. Dose titration was continued through Week 8 to optimize dose. SD-809 ER dose could be adjusted weekly in increments of 6 milligrams per day(mg/day) (6 or 12 mg/day after total daily dose of 48 mg reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day(36 mg twice daily), unless participant was receiving a strong CYP2D6 inhibitor(e.g., paroxetine,buproprion, fluoxetine), in which case maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER Participants who were receiving Food and Drug Administration (FDA) - approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state area under the curve(AUC) of total (alpha+beta)-Dihydrotetrabenazine(HTBZ) metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. SD-809 ER dose could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after total daily dose of 48 mg reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Overall Study STARTED	82	37
Overall Study COMPLETED	56	25
Overall Study NOT COMPLETED	26	12

Reasons for withdrawal

Reasons for withdrawal
Measure	Rollover Cohort: SD-809 ER Participants who completed study SD-809-C-15 (either placebo or SD-809 group \[NCT01795859\], including 1-week washout period and Week 13 evaluation), received 6 milligrams(mg) SD-809 ER tablet once daily as starting dose in this study. Dose titration was continued through Week 8 to optimize dose. SD-809 ER dose could be adjusted weekly in increments of 6 milligrams per day(mg/day) (6 or 12 mg/day after total daily dose of 48 mg reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day(36 mg twice daily), unless participant was receiving a strong CYP2D6 inhibitor(e.g., paroxetine,buproprion, fluoxetine), in which case maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER Participants who were receiving Food and Drug Administration (FDA) - approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state area under the curve(AUC) of total (alpha+beta)-Dihydrotetrabenazine(HTBZ) metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. SD-809 ER dose could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after total daily dose of 48 mg reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Overall Study Death	1	0
Overall Study Adverse Event	11	1
Overall Study Lost to Follow-up	1	0
Overall Study Non-compliance with study drug dosing	1	1
Overall Study Withdrawal by Subject	7	1
Overall Study Require drug that interfere with study	1	4
Overall Study Protocol Violation	1	1
Overall Study Withdrawal per Investigator's judgement	1	1
Overall Study Caregiver can no longer participate	0	2
Overall Study Other than specified	2	1

Baseline Characteristics

Alternatives for Reducing Chorea in Huntington Disease

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Total n=119 Participants Total of all reporting groups
Age, Continuous	53.7 years STANDARD_DEVIATION 12.27 • n=5 Participants	52.4 years STANDARD_DEVIATION 11.48 • n=7 Participants	53.3 years STANDARD_DEVIATION 12.00 • n=5 Participants
Sex: Female, Male Female	37 Participants n=5 Participants	15 Participants n=7 Participants	52 Participants n=5 Participants
Sex: Female, Male Male	45 Participants n=5 Participants	22 Participants n=7 Participants	67 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants	2 Participants n=7 Participants	2 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	82 Participants n=5 Participants	35 Participants n=7 Participants	117 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race/Ethnicity, Customized Black or African American	4 Participants n=5 Participants	0 Participants n=7 Participants	4 Participants n=5 Participants
Race/Ethnicity, Customized White	76 Participants n=5 Participants	36 Participants n=7 Participants	112 Participants n=5 Participants
Race/Ethnicity, Customized Other	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants
Race/Ethnicity, Customized Multiple	2 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants

PRIMARY outcome

Timeframe: Baseline to follow-up visit (up to approximately 3 years 9 months)

Population: Safety population included all participants who received at least 1 dose of study drug.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Entire Treatment Period Any TEAEs	77 Participants	35 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Entire Treatment Period Serious TEAEs	21 Participants	11 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Entire Treatment Period Severe TEAEs	17 Participants	7 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Entire Treatment Period Drug-Related TEAEs	56 Participants	26 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Entire Treatment Period TEAEs Leading to Withdrawal From Study	13 Participants	3 Participants

PRIMARY outcome

Timeframe: Day 1 to end of Week 8

Population: Safety population included all participants who received at least 1 dose of study drug.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Severe AEs=inability to carry out usual activities. Drug-related TEAEs: TEAEs with a possible, probable, definite, or missing relationship to study drug. Serious AEs: death, a life-threatening AE, 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 1 of the outcomes listed in this definition. TEAEs: events that 1) began after treatment with study drug in current study and that were not present at baseline or 2) if present at baseline, had worsened in severity. Any TEAEs included both serious and non-serious TEAEs. A summary of other non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Rollover Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Titration Any TEAEs	49 Participants	—
Rollover Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Titration Serious TEAEs	1 Participants	—
Rollover Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Titration Severe TEAEs	0 Participants	—
Rollover Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Titration Drug-Related TEAEs	23 Participants	—
Rollover Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Titration TEAEs Leading to Withdrawal From Study	0 Participants	—

PRIMARY outcome

Timeframe: Day 1 to end of Week 4

Population: Safety population included all participants received at least 1 dose of study drug.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=37 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Switch Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Dose Adjustment Any TEAEs	17 Participants	—
Switch Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Dose Adjustment Serious TEAEs	1 Participants	—
Switch Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Dose Adjustment Severe TEAEs	1 Participants	—
Switch Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Dose Adjustment Drug-Related TEAEs	11 Participants	—
Switch Cohort: Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Dose Adjustment TEAEs Leading to Withdrawal From Study	0 Participants	—

PRIMARY outcome

Timeframe: Week 8 to follow-up visit (up to approximately 3 years 9 months)

Population: Safety population included all participants who received at least 1 dose of study drug. Here, 'Overall number of participants analyzed' signifies number of participants evaluable for this outcome measure.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=81 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=35 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Long Term Stable Dose Treatment Severe TEAEs	17 Participants	7 Participants
Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Long Term Stable Dose Treatment Any TEAEs	74 Participants	35 Participants
Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Long Term Stable Dose Treatment Serious TEAEs	20 Participants	10 Participants
Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Long Term Stable Dose Treatment Drug-Related TEAEs	49 Participants	22 Participants
Number of Participants With TEAEs, Serious TEAEs, Severe TEAEs, Drug-Related TEAEs, and TEAEs Leading to Withdrawal During Long Term Stable Dose Treatment TEAEs Leading to Withdrawal From Study	13 Participants	3 Participants

SECONDARY outcome

Timeframe: Baseline, Week 158

Population: Safety population included all participants who received at least 1 dose of study drug. Here, 'Number analyzed' signifies participants evaluable for this outcome measure for specified categories.

Clinical laboratory hematology parameters included basophils, eosinophils, leukocytes, lymphocytes, monocytes, neutrophils, platelets, erythrocytes mean corpuscular volume, erythrocytes, hematocrit, and hemoglobin. Change from baseline in basophils, eosinophils, leukocytes, lymphocytes, monocytes, neutrophils and platelets cells at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed values at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Basophils: Baseline	0.029 10^9 cells per liter Standard Deviation 0.0231	0.035 10^9 cells per liter Standard Deviation 0.0283
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Basophils: Change at Week 158	-0.014 10^9 cells per liter Standard Deviation 0.0287	-0.004 10^9 cells per liter Standard Deviation 0.0385
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Eosinophils: Baseline	0.151 10^9 cells per liter Standard Deviation 0.1274	0.195 10^9 cells per liter Standard Deviation 0.1366
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Eosinophils: Change at Week 158	-0.054 10^9 cells per liter Standard Deviation 0.0784	0.009 10^9 cells per liter Standard Deviation 0.0911
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Leukocytes: Baseline	6.98 10^9 cells per liter Standard Deviation 2.083	6.97 10^9 cells per liter Standard Deviation 1.828
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Leukocytes: Change at Week 158	-0.04 10^9 cells per liter Standard Deviation 0.927	-0.04 10^9 cells per liter Standard Deviation 1.098
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Lymphocytes: Baseline	1.922 10^9 cells per liter Standard Deviation 0.7674	1.789 10^9 cells per liter Standard Deviation 0.7088
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Lymphocytes: Change at Week 158	-0.088 10^9 cells per liter Standard Deviation 0.4261	0.075 10^9 cells per liter Standard Deviation 0.5409
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Monocytes: Baseline	0.445 10^9 cells per liter Standard Deviation 0.1805	0.416 10^9 cells per liter Standard Deviation 0.1416
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Monocytes: Change at Week 158	-0.129 10^9 cells per liter Standard Deviation 0.1722	-0.068 10^9 cells per liter Standard Deviation 0.1335
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Neutrophils: Baseline	4.437 10^9 cells per liter Standard Deviation 1.6324	4.538 10^9 cells per liter Standard Deviation 1.4741
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Neutrophils: Change at Week 158	0.243 10^9 cells per liter Standard Deviation 0.6359	-0.050 10^9 cells per liter Standard Deviation 0.8166
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Platelets: Baseline	235.6 10^9 cells per liter Standard Deviation 62.81	247.2 10^9 cells per liter Standard Deviation 77.63
Change From Baseline in Clinical Laboratory Hematology Parameters (Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils and Platelets) at Week 158 Platelets: Change at Week 158	1.2 10^9 cells per liter Standard Deviation 56.09	-12.0 10^9 cells per liter Standard Deviation 26.59

SECONDARY outcome

Timeframe: Baseline, Week 158

Population: Safety population included all participants received at least 1 dose of study drug. Here, 'Number analyzed' signifies participants evaluable for this outcome measure at specified timepoints.

Clinical laboratory hematology parameters included basophils, eosinophils, leukocytes, lymphocytes, monocytes, neutrophils, platelets, erythrocytes mean corpuscular volume, erythrocytes, hematocrit, and hemoglobin. Change from baseline in erythrocytes mean corpuscular volume at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Hematology Parameter (Erythrocytes Mean Corpuscular Volume) at Week 158 Baseline	91.1 femtoliter (fL) Standard Deviation 3.95	92.1 femtoliter (fL) Standard Deviation 5.39
Change From Baseline in Clinical Laboratory Hematology Parameter (Erythrocytes Mean Corpuscular Volume) at Week 158 Change at Week 158	2.2 femtoliter (fL) Standard Deviation 3.23	1.6 femtoliter (fL) Standard Deviation 4.14

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory hematology parameters included basophils, eosinophils, leukocytes, lymphocytes, monocytes, neutrophils, platelets, erythrocytes mean corpuscular volume, erythrocytes, hematocrit, and hemoglobin. Change from baseline in erythrocytes at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Hematology Parameter (Erythrocytes) at Week 158 Baseline	4.60 10^12 cells per liter Standard Deviation 0.397	4.54 10^12 cells per liter Standard Deviation 0.377
Change From Baseline in Clinical Laboratory Hematology Parameter (Erythrocytes) at Week 158 Change at Week 158	0.18 10^12 cells per liter Standard Deviation 0.262	0.19 10^12 cells per liter Standard Deviation 0.247

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory hematology parameters included basophils, eosinophils, leukocytes, lymphocytes, monocytes, neutrophils, platelets, erythrocytes mean corpuscular volume, erythrocytes, hematocrit, and hemoglobin. Hematocrit levels were calculated as the ratio of the volume of red cells to the volume of whole blood. Change from baseline in hematocrit at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Hematology Parameter (Hematocrit) at Week 158 Baseline	0.419 ratio Standard Deviation 0.0363	0.417 ratio Standard Deviation 0.0397
Change From Baseline in Clinical Laboratory Hematology Parameter (Hematocrit) at Week 158 Change at Week 158	0.025 ratio Standard Deviation 0.0255	0.025 ratio Standard Deviation 0.0334

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory hematology parameters included basophils, eosinophils, leukocytes, lymphocytes, monocytes, neutrophils, platelets, erythrocytes mean corpuscular volume, erythrocytes, hematocrit, and hemoglobin. Change from baseline in hemoglobin at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Hematology Parameter (Hemoglobin) at Week 158 Change at Week 158	4.6 grams per liter (g/L) Standard Deviation 7.99	4.5 grams per liter (g/L) Standard Deviation 11.99
Change From Baseline in Clinical Laboratory Hematology Parameter (Hemoglobin) at Week 158 Baseline	139.7 grams per liter (g/L) Standard Deviation 12.26	138.4 grams per liter (g/L) Standard Deviation 13.19

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory serum chemistry parameters included alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium, triglycerides, protein, albumin, creatinine clearance, bilirubin, creatinine, direct bilirubin, and urate. Change from baseline in alanine aminotransferase and alkaline phosphatase at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Alanine Aminotransferase and Alkaline Phosphatase) at Week 158 Alanine Aminotransferase: Baseline	20.7 international units per liter (IU/L) Standard Deviation 9.74	18.9 international units per liter (IU/L) Standard Deviation 12.20
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Alanine Aminotransferase and Alkaline Phosphatase) at Week 158 Alanine Aminotransferase: Change at Week 158	-5.3 international units per liter (IU/L) Standard Deviation 7.51	-2.1 international units per liter (IU/L) Standard Deviation 9.74
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Alanine Aminotransferase and Alkaline Phosphatase) at Week 158 Alkaline Phosphatase: Baseline	72.6 international units per liter (IU/L) Standard Deviation 20.24	73.1 international units per liter (IU/L) Standard Deviation 20.61
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Alanine Aminotransferase and Alkaline Phosphatase) at Week 158 Alkaline Phosphatase: Change at Week 158	-1.0 international units per liter (IU/L) Standard Deviation 8.21	1.0 international units per liter (IU/L) Standard Deviation 9.62

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory serum chemistry parameters included alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium, triglycerides, protein, albumin, creatinine clearance, bilirubin, creatinine, direct bilirubin, and urate. Change from baseline in aspartate aminotransferase and lactate dehydrogenase at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Aspartate Aminotransferase and Lactate Dehydrogenase) at Week 158 Aspartate Aminotransferase: Baseline	20.5 units per liter (U/L) Standard Deviation 5.84	18.4 units per liter (U/L) Standard Deviation 6.88
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Aspartate Aminotransferase and Lactate Dehydrogenase) at Week 158 Aspartate Aminotransferase: Change at Week 158	-2.7 units per liter (U/L) Standard Deviation 5.43	-1.1 units per liter (U/L) Standard Deviation 5.40
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Aspartate Aminotransferase and Lactate Dehydrogenase) at Week 158 Lactate Dehydrogenase: Baseline	163.9 units per liter (U/L) Standard Deviation 28.05	161.1 units per liter (U/L) Standard Deviation 42.32
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Aspartate Aminotransferase and Lactate Dehydrogenase) at Week 158 Lactate Dehydrogenase: Change at Week 158	-5.5 units per liter (U/L) Standard Deviation 27.83	-4.9 units per liter (U/L) Standard Deviation 18.45

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory serum chemistry parameters included alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium, triglycerides, protein, albumin, creatinine clearance, bilirubin, creatinine, direct bilirubin, and urate. Change from baseline in bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium and triglycerides at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory serum chemistry parameters included alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium, triglycerides, protein, albumin, creatinine clearance, bilirubin, creatinine, direct bilirubin, and urate. Change from baseline in protein and albumin at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Protein and Albumin) at Week 158 Protein: Baseline	69.5 g/L Standard Deviation 3.88	67.3 g/L Standard Deviation 4.54
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Protein and Albumin) at Week 158 Protein: Change at Week 158	-0.9 g/L Standard Deviation 3.54	-2.9 g/L Standard Deviation 4.43
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Protein and Albumin) at Week 158 Albumin: Baseline	43.9 g/L Standard Deviation 2.55	43.1 g/L Standard Deviation 2.65
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Protein and Albumin) at Week 158 Albumin: Change at Week 158	0.2 g/L Standard Deviation 3.61	-0.9 g/L Standard Deviation 2.57

SECONDARY outcome

Timeframe: Baseline, Week 106

Clinical laboratory serum chemistry parameters included alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium, triglycerides, protein, albumin, creatinine clearance, bilirubin, creatinine, direct bilirubin, and urate. Change from baseline in creatinine clearance at baseline and Week 106 is reported in this outcome measure. Observed value at baseline and observed value at Week 106 were used to calculate the change from baseline value at Week 106.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Serum Chemistry Parameter (Creatinine Clearance) at Week 106 Baseline	94.1 milliliters per minute (mL/min) Standard Deviation 26.67	89.9 milliliters per minute (mL/min) Standard Deviation 27.55
Change From Baseline in Clinical Laboratory Serum Chemistry Parameter (Creatinine Clearance) at Week 106 Change at Week 106	-4.5 milliliters per minute (mL/min) Standard Deviation 6.36	-34.0 milliliters per minute (mL/min)

SECONDARY outcome

Timeframe: Baseline, Week 158

Clinical laboratory serum chemistry parameters included alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, bicarbonate, blood urea nitrogen, calcium, chloride, cholesterol, glucose, magnesium, phosphate, potassium, sodium, triglycerides, protein, albumin, creatinine clearance, bilirubin, creatinine, direct bilirubin, and urate. Change from baseline in bilirubin, creatinine, direct bilirubin, and urate at baseline and Week 158 is reported in this outcome measure. Observed value at baseline and observed value at Week 158 were used to calculate the change from baseline value at Week 158.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Bilirubin: Baseline	7.8 micromoles per liter Standard Deviation 4.82	6.0 micromoles per liter Standard Deviation 2.43
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Bilirubin: Change at Week 158	-0.7 micromoles per liter Standard Deviation 2.51	-1.4 micromoles per liter Standard Deviation 2.07
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Creatinine: Baseline	82.8 micromoles per liter Standard Deviation 16.81	84.2 micromoles per liter Standard Deviation 19.02
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Creatinine: Change at Week 158	-2.4 micromoles per liter Standard Deviation 10.13	-2.4 micromoles per liter Standard Deviation 6.46
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Direct Bilirubin: Baseline	2.4 micromoles per liter Standard Deviation 0.94	2.1 micromoles per liter Standard Deviation 0.35
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Direct Bilirubin: Change at Week 158	0.1 micromoles per liter Standard Deviation 0.23	-0.2 micromoles per liter Standard Deviation 0.44
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Urate: Baseline	305.2 micromoles per liter Standard Deviation 83.70	269.5 micromoles per liter Standard Deviation 75.06
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bilirubin, Creatinine, Direct Bilirubin, and Urate) at Week 158 Urate: Change at Week 158	-21.8 micromoles per liter Standard Deviation 55.50	-3.4 micromoles per liter Standard Deviation 39.37

SECONDARY outcome

Timeframe: Baseline, Week 171

Population: Safety population included all participants who received at least 1 dose of study drug. Here, 'Number of participants analyzed' signifies participants evaluable for this outcome measure for specified categories.

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were assessed in seated/supine position. Observed value at baseline and observed value at Week 171 were used to calculate the change from baseline value at Week 171.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Blood Pressure at Week 171 SBP: Baseline	120.5 millimeters of mercury (mmHg) Standard Deviation 12.70	118.9 millimeters of mercury (mmHg) Standard Deviation 17.80
Change From Baseline in Blood Pressure at Week 171 SBP: Change at Week 171	-4.0 millimeters of mercury (mmHg)	—
Change From Baseline in Blood Pressure at Week 171 DBP: Baseline	73.3 millimeters of mercury (mmHg) Standard Deviation 10.21	73.8 millimeters of mercury (mmHg) Standard Deviation 11.85
Change From Baseline in Blood Pressure at Week 171 DBP: Change at Week 171	-6.0 millimeters of mercury (mmHg)	—

SECONDARY outcome

Timeframe: Baseline, Week 171

Heart rate was assessed in seated/supine position. Observed value at baseline and observed value at Week 171 were used to calculate the change from baseline value at Week 171.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Heart Rate at Week 171 Baseline	70.7 beats per minute Standard Deviation 8.68	68.1 beats per minute Standard Deviation 12.56
Change From Baseline in Heart Rate at Week 171 Change at Week 171	25.0 beats per minute	—

SECONDARY outcome

Timeframe: Baseline, Week 171

Observed value at baseline and observed value at Week 171 were used to calculate the change from baseline value at Week 171.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Respiration Rate at Week 171 Baseline	16.4 breaths/minute Standard Deviation 2.57	17.5 breaths/minute Standard Deviation 2.58
Change From Baseline in Respiration Rate at Week 171 Change at Week 171	-1.3 breaths/minute Standard Deviation 2.06	-3.5 breaths/minute Standard Deviation 3.54

SECONDARY outcome

Timeframe: Baseline, Week 171

Observed value at baseline and observed value at Week 171 were used to calculate the change from baseline value at Week 171.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Body Temperature at Week 171 Baseline	36.56 degrees centigrade Standard Deviation 0.427	36.67 degrees centigrade Standard Deviation 0.309
Change From Baseline in Body Temperature at Week 171 Change at Week 171	-0.13 degrees centigrade Standard Deviation 0.468	-0.10 degrees centigrade Standard Deviation 0.283

SECONDARY outcome

Timeframe: Baseline, Week 8

ECG parameters included heart rate, PR interval, QRS duration, QT interval and Fridericia's corrected QT interval (QTcF). Heart rate measured by ECG at Baseline and Week 8 is reported in this outcome measure.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Electrocardiogram (ECG) Parameter Value (Heart Rate) at Baseline and Week 8 Baseline	67.4 beats/minute Standard Deviation 9.87	63.8 beats/minute Standard Deviation 13.96
Electrocardiogram (ECG) Parameter Value (Heart Rate) at Baseline and Week 8 Week 8	64.6 beats/minute Standard Deviation 9.22	65.8 beats/minute Standard Deviation 13.50

SECONDARY outcome

Timeframe: Baseline, Week 8

ECG parameters included heart rate, PR interval, QRS duration, QT interval and QTcF. PR interval, QRS duration, QT interval and QTcF at Baseline and Week 8 is reported in this outcome measure.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 PR Interval: Baseline	164.1 milliseconds Standard Deviation 25.03	159.5 milliseconds Standard Deviation 22.65
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 PR Interval: Week 8	165.2 milliseconds Standard Deviation 23.87	155.7 milliseconds Standard Deviation 18.08
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 QRS Duration: Baseline	92.8 milliseconds Standard Deviation 14.37	88.8 milliseconds Standard Deviation 10.16
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 QRS Duration: Week 8	91.0 milliseconds Standard Deviation 12.09	88.0 milliseconds Standard Deviation 10.97
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 QT Interval: Baseline	399.8 milliseconds Standard Deviation 27.44	415.6 milliseconds Standard Deviation 37.44
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 QT Interval: Week 8	405.1 milliseconds Standard Deviation 29.10	404.5 milliseconds Standard Deviation 35.43
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 QTcF: Baseline	413.3 milliseconds Standard Deviation 18.67	419.3 milliseconds Standard Deviation 17.89
ECG Parameter Value (PR Interval, QRS Duration, QT Interval, QTcF) at Baseline and Week 8 QTcF: Week 8	412.7 milliseconds Standard Deviation 20.10	412.8 milliseconds Standard Deviation 18.05

SECONDARY outcome

Timeframe: Baseline, Week 8

ECG parameters included heart rate, PR interval, QRS duration, QT interval and QTcF. Clinical significance was as as per Investigator's discretion.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Number of Participants With Clinically Significant Abnormalities in ECG Parameters Baseline	5 Participants	0 Participants
Number of Participants With Clinically Significant Abnormalities in ECG Parameters Week 8	2 Participants	0 Participants

SECONDARY outcome

Timeframe: From Day 1 until the first day at which the participant was taking the dose level they were receiving at Week 8 (up to maximum 1284 days)

Population: Safety population included all participants who received at least 1 dose of study drug. Here, 'Overall number of participants analyzed' signifies participants evaluable for this outcome measure.

Duration of time to achieve stable dose of SD-809, defined as the number of days from Day 1 until the first day at which the participant was taking the dose level they were receiving at Week 8.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=81 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=35 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Duration of Time to Achieve a Stable Dose of SD-809 ER	47.0 days Interval 1.0 to 73.0	28.0 days Interval 1.0 to 76.0

SECONDARY outcome

Timeframe: Baseline, Week 171

The UPDRS is a comprehensive instrument used to assess the signs and symptoms of Parkinson's disease and includes patient and clinician-based assessments of motor, cognitive, and behavioral symptoms. The UPDRS-Dysarthria question pertaining to speech/dysarthria was used to monitor study participants for parkinsonism. Participants rated their responses on a scale ranging from 0 to 4, where 0 = normal; 1 = mildly affected, no difficulty being understood; 2 = moderately affected, sometimes asked to repeat statements; 3 = severely affected, frequently asked to repeat statements; 4 = unintelligible most of the time. Higher scores indicated greater impairment.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Unified Parkinson's Disease Rating Scale (UPDRS) -Dysarthria Score at Week 171 Baseline	0.9 units on a scale Standard Deviation 0.79	1.1 units on a scale Standard Deviation 0.74
Change From Baseline in Unified Parkinson's Disease Rating Scale (UPDRS) -Dysarthria Score at Week 171 Change at Week 171	0.4 units on a scale Standard Deviation 0.79	1.5 units on a scale Standard Deviation 0.71

SECONDARY outcome

Timeframe: Baseline, Week 171

BARS is a rating scale for evaluation of drug-induced akathisia. It includes a summary score (objective assessment of akathisia and subjective measures \[self-awareness and distress\]) and a global clinical assessment. Objective akathisia rated on a scale of 0-3 (0=normal, occasional fidgety movements of limbs; 1=characteristic restless movements for less than half the time observed; 2= characteristic restless movements for at least half the time observed; 3=constant characteristic restless movements). Subjective measures included awareness of restlessness (rated on a scale of 0 \[absence of inner restlessness\] to 3 \[awareness of intense compulsion to move\]) and distress related to restlessness (rated on a scale of 0 \[no distress\] to 3 \[severe distress\]). Objective akathisia and subjective measures summed to yield summary score ranging from 0 (no akathisia and restlessness) to 9 (severe akathisia and restlessness), where higher scores indicated more akathisia and restlessness.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Barnes Akathisia Rating Scale (BARS) Summary Score at Week 171 Baseline	1.1 units on a scale Standard Deviation 1.67	0.8 units on a scale Standard Deviation 1.25
Change From Baseline in Barnes Akathisia Rating Scale (BARS) Summary Score at Week 171 Change at Week 171	0.7 units on a scale Standard Deviation 1.50	0.5 units on a scale Standard Deviation 3.54

SECONDARY outcome

Timeframe: Baseline, Week 171

BARS is a rating scale for evaluation of drug-induced akathisia. It includes a summary score (objective assessment of akathisia and subjective measures \[self-awareness and distress\]) and a global clinical assessment. Global clinical assessment rated on a scale ranging from 0 to 5, where 0=Absent. No evidence of awareness of restlessness; 1=Questionable. Non-specific inner tension and fidgety movements; 2=Mild akathisia. Awareness of restlessness in legs and/or inner restlessness worse when required to stand still. Fidgety movements present, but characteristic restless movements not necessarily observed; 3=Moderate akathisia. Awareness of restlessness combined with characteristic restless movements; 4=Marked akathisia. Subjective experience of restlessness includes a compulsive desire to walk or pace; 5=Severe akathisia. Strong compulsion to pace up and down most of the time. Constant restlessness associated with intense distress and insomnia. Higher scores indicated more akathisia.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Barnes Akathisia Rating Scale (BARS) Global Assessment Score at Week 171 Baseline	0.5 units on a scale Standard Deviation 0.83	0.4 units on a scale Standard Deviation 0.68
Change From Baseline in Barnes Akathisia Rating Scale (BARS) Global Assessment Score at Week 171 Change at Week 171	0.4 units on a scale Standard Deviation 0.79	1.0 units on a scale Standard Deviation 1.41

SECONDARY outcome

Timeframe: Baseline, Week 171

HADS is a self-administered instrument reliable for detecting states of depression and anxiety It includes 2 subscales: Hospital Anxiety and Depression Scale - anxiety (HADS-A) assesses state of generalized anxiety (anxious mood, restlessness, anxious thoughts, panic attacks); Hospital Anxiety and Depression Scale - depression (HADS-D) assesses state of lost interest and diminished pleasure response (lowering of hedonic tone). Each subscale comprised of 7 items with range 0 (no presence of anxiety or depression) to 3 (severe feeling of anxiety or depression). Total score ranged from 0 to 21 for each subscale; where higher score indicated greater severity of anxiety and depression symptoms.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Hospital Anxiety and Depression Scale (HADS) Anxiety Subscale Score at Week 171 Baseline	2.7 units on a scale Standard Deviation 2.99	4.3 units on a scale Standard Deviation 3.45
Change From Baseline in Hospital Anxiety and Depression Scale (HADS) Anxiety Subscale Score at Week 171 Change at Week 171	1.3 units on a scale Standard Deviation 2.63	-2.5 units on a scale Standard Deviation 2.12

SECONDARY outcome

Timeframe: Baseline, Week 171

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Hospital Anxiety and Depression Scale (HADS) Depression Subscale Score at Week 171 Baseline	2.0 units on a scale Standard Deviation 2.47	3.4 units on a scale Standard Deviation 2.54
Change From Baseline in Hospital Anxiety and Depression Scale (HADS) Depression Subscale Score at Week 171 Change at Week 171	2.4 units on a scale Standard Deviation 5.26	2.0 units on a scale Standard Deviation 4.24

SECONDARY outcome

Timeframe: Baseline, Week 171

ESS is a self-administered questionnaire comprised of 8 questions that provides a measure of a participant's general level of daytime sleepiness. Participants were asked to rate their usual chances of dozing off or falling asleep in different situations or activities that most people engage in as part of their daily lives (sitting and reading; watching TV; sitting inactive in a public place; as a passenger in a car for an hour without a break; lying down to rest in the afternoon when circumstances permit; sitting and talking to someone; sitting quietly after a lunch without alcohol; in a car, while stopped for a few minutes in traffic), on a 4-point Likert scale ranging from 0 to 3, where 0=no chance; 1=slight chance; 2=moderate chance; 3=high chance. Total ESS score is the sum of 8 item-scores and can range between 0 and 24 with a higher the score indicating a higher level of daytime sleepiness.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Epworth Sleepiness Scale (ESS) Total Score at Week 171 Baseline	4.4 units on a scale Standard Deviation 3.72	6.0 units on a scale Standard Deviation 4.15
Change From Baseline in Epworth Sleepiness Scale (ESS) Total Score at Week 171 Change at Week 171	4.7 units on a scale Standard Deviation 7.45	1.0 units on a scale Standard Deviation 1.41

SECONDARY outcome

Timeframe: Baseline up to 1-week follow-up visit (up to approximately 3 years 9 months)

C-SSRS is a clinician rated assessment of suicidal behavior and ideation categorized as: Suicidal behavior=a "yes" response to any of 5 suicidal behavior questions (preparatory acts or behavior, aborted attempt, interrupted attempt, non-fatal suicide attempt, and completed suicide); Suicidal ideation=a "yes" response to any one of 5 suicidal ideation questions which includes wish to be dead, non-specific active suicidal thoughts, active suicidal ideation with any methods (not plan) without intent to act, active suicidal ideation with some intent to act without specific plan, active suicidal ideation with specific plan and intent. Number of participants with positive response (response of "yes") to suicidal behavior, ideation or any non-suicidal self-injurious behavior was reported.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=81 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Number of Participants With Positive Response on the Columbia Suicide Severity Rating Scale (C-SSRS) Suicidal Ideation	11 Participants	4 Participants
Number of Participants With Positive Response on the Columbia Suicide Severity Rating Scale (C-SSRS) Suicidal Behavior	3 Participants	1 Participants
Number of Participants With Positive Response on the Columbia Suicide Severity Rating Scale (C-SSRS) Self-injurious behavior without suicidal intent	1 Participants	0 Participants

SECONDARY outcome

Timeframe: Baseline, Week 171

MoCA is a validated rapid screening instrument for assessing mild cognitive dysfunction. It assesses different cognitive domains: attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation by using 30 questions test. Time to administer the MoCA© is approximately 10 minutes. The total possible score ranges from 0 (worst) to 30 (best) points; where higher scores indicate better cognitive function. A score of 26 or above is considered normal and a score below 26 is considered as recognitive dysfunction.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Montreal Cognitive Assessment (MoCA) Total Score at Week 171 Change at Week 171	-3.1 units on a scale Standard Deviation 4.81	4.5 units on a scale Standard Deviation 3.54
Change From Baseline in Montreal Cognitive Assessment (MoCA) Total Score at Week 171 Baseline	23.9 units on a scale Standard Deviation 4.35	21.9 units on a scale Standard Deviation 3.86

SECONDARY outcome

Timeframe: Baseline, Week 171

The UHDRS is a research tool developed by the Huntington Disease (HD) Study Group to provide a uniform assessment of the clinical features and course of HD. The components of the full UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities. The total behavior score is made up of subscores evaluating depressed mood, apathy, low self-esteem/guilt, compulsive behavior, anxiety, irritable behavior, perseverative/obsessive thinking, disruptive/aggressive behavior, suicidal thoughts, delusions, and hallucinations. For each subscore the frequency and severity was assessed separately. Frequency was rated on a scale of 0 (never or almost never) to 4 (very frequently, most of the time). Severity was rated on a scale of 0 (no evidence) to 4 (severe). Total behavior score ranges from 0 (no impairment) to 88 (severe impairment). Higher scores indicated greater behavioral impairments.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Unified Huntington's Disease Rating Scale (UHDRS) Total Behavior Score at Week 171 Baseline	7.1 units on a scale Standard Deviation 8.26	10.9 units on a scale Standard Deviation 10.66
Change From Baseline in Unified Huntington's Disease Rating Scale (UHDRS) Total Behavior Score at Week 171 Change at Week 171	8.6 units on a scale Standard Deviation 12.47	4.5 units on a scale Standard Deviation 2.12

SECONDARY outcome

Timeframe: Baseline, Week 28

The UHDRS is a research tool developed by HD Study Group to provide a uniform assessment of the clinical features and course of HD. The components of the full UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities. Functional assessment included 25 questions with possible answers 'yes' or 'no'. Total score ranges from 0 (worst) to 25 (best). Higher scores indicate better functional ability.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in UHDRS Functional Assessment Score at Week 28 Baseline	21.4 units on a scale Standard Deviation 3.00	18.2 units on a scale Standard Deviation 4.94
Change From Baseline in UHDRS Functional Assessment Score at Week 28 Change at Week 28	-1.6 units on a scale Standard Deviation 2.76	-1.6 units on a scale Standard Deviation 3.62

SECONDARY outcome

Timeframe: Baseline, Week 28

UHDRS: research tool to provide a uniform assessment of clinical features and course of HD. Components of UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities. Independence scale ranges from 10-100, indicating most accurate current level of participant's independence. 10=Tube fed, total bed care; 20=No speech, must be fed; 30=Participant provides minimal assistance in own feeding,bathing,toileting; 40=Chronic care facility needed; limited self-feeding; 50=24-hour supervision appropriate; assistance required for bathing,eating,toileting; 60=Needs minor assistance in dressing,toileting,bathing; 70=Self-care maintained for bathing,limited household duties; unable to manage finances; 80=Pre-disease level of employment changes or ends; cannot perform household chores, may need help with finances; 90=No physical care needed(difficult tasks avoided); 100=No special care needed. Higher scores indicate better independence.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in UHDRS Independence Scale Score at Week 28 Baseline	84.0 units on a scale Standard Deviation 9.48	75.5 units on a scale Standard Deviation 11.59
Change From Baseline in UHDRS Independence Scale Score at Week 28 Change at Week 28	-4.2 units on a scale Standard Deviation 9.60	-1.2 units on a scale Standard Deviation 8.93

SECONDARY outcome

Timeframe: Baseline, Week 132

UHDRS is a research tool developed by HD Study Group to provide a uniform assessment of the clinical features and course of HD. Components of the full UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities (TFC). TFC is a 5-item clinician rating scale typically completed after a brief interview with a participant and/or collateral source. TFC globally assesses occupation, finances, domestic chores, activities of daily living, and level of care, with scores on each item ranging from 0 to either 2 or 3 (e.g., Occupation: 0 = unable, 1 = marginal work only, 2 = reduced capacity for usual job, 3 = normal). The five items are summed to yield a TFC total score, which ranges from 0 (normal function) to 13 (severe dysfunction). Higher scores indicated better functioning.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in UHDRS Total Functional Capacity (TFC) Score at Week 132 Baseline	9.6 units on a scale Standard Deviation 2.17	8.3 units on a scale Standard Deviation 2.11
Change From Baseline in UHDRS Total Functional Capacity (TFC) Score at Week 132 Change at Week 132	-3.1 units on a scale Standard Deviation 2.86	-3.1 units on a scale Standard Deviation 2.71

SECONDARY outcome

Timeframe: Baseline, Week 171

Components of UHDRS assess motor function,cognition,behaviour,functional abilities,independence scale, total functional capacities. Cognitive assessment component:verbal fluency(VF) score (memory,attention)(requiring participant to generate as many words as possible beginning with a specific letter\[F,A,S\]in 60 seconds \[sec\]. Score\[no range\]:total number of correct words for 3 letters), symbol digit modalities test(SDMT) score(psychomotor speed,attention)(participant is required to pair digits to assigned symbols using a reference key. Score\[0 {worst}-120 {best}\]:total number of correct written responses in 90 sec), \& Stroop interference(SI) score (selective attention,executive function)(includes 3 conditions:naming colour blocks\[blue, red or green\]; reading colour words printed in black ink; naming ink colour of incongruous colour words. For each condition score(no range)is number of correct responses produced in 45 sec). In these tests, higher scores reflect better cognitive ability.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in UHDRS Cognitive Assessment Score at Week 171 VF Score: Baseline	25.1 units on a scale Standard Deviation 11.00	21.5 units on a scale Standard Deviation 10.79
Change From Baseline in UHDRS Cognitive Assessment Score at Week 171 VF Score: Change at Week 171	-10.9 units on a scale Standard Deviation 10.12	4.0 units on a scale Standard Deviation 5.66
Change From Baseline in UHDRS Cognitive Assessment Score at Week 171 SDMT: Baseline	24.4 units on a scale Standard Deviation 8.91	22.7 units on a scale Standard Deviation 17.38
Change From Baseline in UHDRS Cognitive Assessment Score at Week 171 SDMT: Change at Week 171	-9.6 units on a scale Standard Deviation 7.04	0.0 units on a scale Standard Deviation 7.07
Change From Baseline in UHDRS Cognitive Assessment Score at Week 171 SI Score: Baseline	3.2 units on a scale Standard Deviation 10.87	-0.5 units on a scale Standard Deviation 6.38
Change From Baseline in UHDRS Cognitive Assessment Score at Week 171 SI Score: Change at Week 171	-2.4 units on a scale Standard Deviation 7.42	6.5 units on a scale Standard Deviation 4.27

SECONDARY outcome

Timeframe: Baseline, Week 171

UHDRS is a research tool developed by HD Study Group to provide a uniform assessment of the clinical features and course of HD. Components of the full UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities. Motor function assessment includes total motor score (TMS) and TMC score. TMC score is determined from Item 12 (maximal chorea) of UHDRS TMS and quantifies chorea based on assessments of the face, bucco-oral-lingual area, trunk, and the 4 extremities. TMC score is a sum of chorea scores in the 7 body regions, ranging from 0 (absent chorea) to 28 (marked/prolonged chorea). Lower TMC scores indicated less chorea.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in UHDRS Motor Assessment: Total Maximal Chorea (TMC) Score at Week 171 Change at Week 171	-3.71 units on a scale Standard Deviation 7.544	4.75 units on a scale Standard Deviation 1.061
Change From Baseline in UHDRS Motor Assessment: Total Maximal Chorea (TMC) Score at Week 171 Baseline	12.04 units on a scale Standard Deviation 4.113	12.46 units on a scale Standard Deviation 5.221

SECONDARY outcome

Timeframe: Week 8, Week 171

UHDRS is a research tool developed by HD Study Group to provide a uniform assessment of clinical features and course of HD. Components of full UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities. Motor function assessment includes TMS and TMC score. TMC score is determined from Item 12 (maximal chorea) of UHDRS TMS and quantifies chorea based on assessments of the face, bucco-oral-lingual area, trunk, and the 4 extremities. TMC score is a sum of chorea scores in the 7 body regions, ranging from 0(absent chorea) to 28 (marked/prolonged chorea). Lower TMC scores indicated less chorea. Data was measured and available for total safety population. Data was not available by individual cohorts (rollover cohort and switch cohort) from Week 8 to Week 171, as was done for change from baseline. Therefore, in order to present results data for this outcome measure, the total, combined safety population treatment arm was used.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=119 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Week 8 in UHDRS Motor Assessment: TMC Score at Week 171 Week 8	8.5 units on a scale Standard Deviation 4.67	—
Change From Week 8 in UHDRS Motor Assessment: TMC Score at Week 171 Change at Week 171	2.4 units on a scale Standard Deviation 5.00	—

SECONDARY outcome

Timeframe: Baseline, Week 171

UHDRS is a research tool developed by HD Study Group to provide a uniform assessment of the clinical features and course of HD. Components of the full UHDRS assess motor function, cognition, behaviour, functional abilities, independence scale and total functional capacities. Motor function assessment includes TMS and TMC score. The UHDRS TMS assesses all the motor features of HD and includes maximal chorea, maximal dystonia, ocular pursuit, saccade initiation and velocity, dysarthria, tongue protrusion, finger tapping, hand pronation and supination, luria, rigidity, bradykinesia, gait, tandem walking, and retropulsion pull test. Each of these was rated on a scale of 0 (normal motor function) to 4 (severely impaired motor function). TMS score is a sum of individual scores ranging from 0 (normal motor function) to 124 (severely impaired motor function). Lower TMS scores indicate better motor function.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in UHDRS Motor Assessment: Total Motor Score (TMS) at Week 171 Baseline	34.67 units on a scale Standard Deviation 16.119	37.76 units on a scale Standard Deviation 18.605
Change From Baseline in UHDRS Motor Assessment: Total Motor Score (TMS) at Week 171 Change at Week 171	11.29 units on a scale Standard Deviation 14.762	18.50 units on a scale Standard Deviation 3.536

SECONDARY outcome

Timeframe: Week 8, Week 171

Components of full UHDRS assess motor function,cognition,behaviour,functional abilities,independence scale,total functional capacities. Motor function assessment includes TMS and TMC score. TMS assesses all motor features of HD and includes maximal chorea, maximal dystonia,ocular pursuit,saccade initiation and velocity,dysarthria,tongue protrusion,finger tapping,hand pronation and supination,luria rigidity,bradykinesia,gait,tandem walking,retropulsion pull test. Each of these was rated on a scale of 0(normal motor function) to 4(severely impaired motor function). TMS score is a sum of individual scores ranging from 0(normal motor function) to 124(severely impaired motor function). Lower TMS scores= better motor function. Data was available for total safety population, not by individual cohorts(rollover and switch cohort) from Week 8 to Week 171,as was done for change from baseline. Therefore, in order to present results data,the total,combined safety population treatment arm was used.

Outcome measures

Outcome measures
Measure	Rollover Cohort: SD-809 ER n=119 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Week 8 in UHDRS Motor Assessment: TMS at Week 171 Week 8	30.7 units on a scale Standard Deviation 17.40	—
Change From Week 8 in UHDRS Motor Assessment: TMS at Week 171 Change at Week 171	22.2 units on a scale Standard Deviation 12.02	—

Adverse Events

Rollover Cohort: SD-809 ER

Serious events: 21 serious events

Other events: 74 other events

Deaths: 1 deaths

Switch Cohort: SD-809 ER

Serious events: 11 serious events

Other events: 32 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

Director, Clinical Research

Teva Branded Pharmaceutical Products, R&D Inc

Phone: 215-591-3000

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee Sponsor has the right 60 days before submission for publication to review/provide comments. If the Sponsor's review shows that potentially patentable subject matter would be disclosed, publication or public disclosure shall be delayed for up to 90 additional days in order for the Sponsor, or Sponsor's designees, to file the necessary patent applications. In multicenter trials, each PI will postpone single center publications until after disclosure or publication of multicenter data.
Publication restrictions are in place

Restriction type: OTHER

Measure	Rollover Cohort: SD-809 ER n=82 Participants Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 Participants Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Bicarbonate: Baseline	24.7 millimoles per liter (mmol/L) Standard Deviation 2.55	24.7 millimoles per liter (mmol/L) Standard Deviation 2.06
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Bicarbonate: Change at Week 158	-0.2 millimoles per liter (mmol/L) Standard Deviation 2.87	0.7 millimoles per liter (mmol/L) Standard Deviation 3.16
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Blood Urea Nitrogen: Baseline	5.979 millimoles per liter (mmol/L) Standard Deviation 1.8432	6.282 millimoles per liter (mmol/L) Standard Deviation 1.8177
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Blood Urea Nitrogen: Change at Week 158	-0.531 millimoles per liter (mmol/L) Standard Deviation 1.4864	-0.323 millimoles per liter (mmol/L) Standard Deviation 0.9797
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Calcium: Baseline	2.417 millimoles per liter (mmol/L) Standard Deviation 0.1067	2.393 millimoles per liter (mmol/L) Standard Deviation 0.1523
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Calcium: Change at Week 158	-0.034 millimoles per liter (mmol/L) Standard Deviation 0.1282	-0.067 millimoles per liter (mmol/L) Standard Deviation 0.0869
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Chloride: Baseline	102.5 millimoles per liter (mmol/L) Standard Deviation 2.28	103.8 millimoles per liter (mmol/L) Standard Deviation 2.24
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Chloride: Change at Week 158	-2.7 millimoles per liter (mmol/L) Standard Deviation 2.62	-2.0 millimoles per liter (mmol/L) Standard Deviation 1.50
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Cholesterol: Baseline	5.118 millimoles per liter (mmol/L) Standard Deviation 0.9505	4.863 millimoles per liter (mmol/L) Standard Deviation 1.1686
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Cholesterol: Change at Week 158	-0.131 millimoles per liter (mmol/L) Standard Deviation 0.8790	-0.173 millimoles per liter (mmol/L) Standard Deviation 0.7715
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Glucose: Baseline	5.28 millimoles per liter (mmol/L) Standard Deviation 1.571	5.31 millimoles per liter (mmol/L) Standard Deviation 1.029
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Glucose: Change at Week 158	-0.54 millimoles per liter (mmol/L) Standard Deviation 1.018	-0.64 millimoles per liter (mmol/L) Standard Deviation 1.033
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Magnesium: Baseline	0.871 millimoles per liter (mmol/L) Standard Deviation 0.0566	0.843 millimoles per liter (mmol/L) Standard Deviation 0.0567
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Magnesium: Change at Week 158	-0.027 millimoles per liter (mmol/L) Standard Deviation 0.0701	0.016 millimoles per liter (mmol/L) Standard Deviation 0.0639
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Phosphate: Baseline	1.194 millimoles per liter (mmol/L) Standard Deviation 0.1769	1.191 millimoles per liter (mmol/L) Standard Deviation 0.1661
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Phosphate: Change at Week 158	-0.029 millimoles per liter (mmol/L) Standard Deviation 0.2298	0.061 millimoles per liter (mmol/L) Standard Deviation 0.1330
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Potassium: Baseline	4.39 millimoles per liter (mmol/L) Standard Deviation 0.419	4.46 millimoles per liter (mmol/L) Standard Deviation 0.332
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Potassium: Change at Week 158	-0.14 millimoles per liter (mmol/L) Standard Deviation 0.414	0.19 millimoles per liter (mmol/L) Standard Deviation 0.501
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Sodium: Baseline	142.4 millimoles per liter (mmol/L) Standard Deviation 2.14	142.9 millimoles per liter (mmol/L) Standard Deviation 2.31
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Sodium: Change at Week 158	-2.0 millimoles per liter (mmol/L) Standard Deviation 3.56	-1.7 millimoles per liter (mmol/L) Standard Deviation 2.06
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Triglycerides: Baseline	1.606 millimoles per liter (mmol/L) Standard Deviation 1.0001	1.733 millimoles per liter (mmol/L) Standard Deviation 1.2887
Change From Baseline in Clinical Laboratory Serum Chemistry Parameters (Bicarbonate, Blood Urea Nitrogen, Calcium, Chloride, Cholesterol, Glucose, Magnesium, Phosphate, Potassium, Sodium, Triglycerides) at Week 158 Triglycerides: Change at Week 158	-0.147 millimoles per liter (mmol/L) Standard Deviation 0.8692	-0.420 millimoles per liter (mmol/L) Standard Deviation 1.0005

Measure	Rollover Cohort: SD-809 ER n=82 participants at risk Participants who completed study SD-809-C-15 (either placebo group or SD-809 group, including 1-week washout period and Week 13 evaluation), received 6 mg SD-809 ER tablet once daily as a starting dose in this study. Dose titration was continued through Week 8 to optimize the dose. Dose of SD-809 ER could be adjusted weekly in increments of 6 mg/day (6 or 12 mg/day after a total daily dose of 48 mg was reached) based on chorea control and adverse events. Daily doses of SD-809 ER 12 mg and higher were administered twice daily. Maximum total daily dose of SD-809 ER was 72 mg/day (36 mg twice daily), unless the participant was receiving a strong CYP2D6 inhibitor (e.g., paroxetine, buproprion, and fluoxetine), in which case the maximum total daily dose was 42 mg (21 mg twice daily). Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.	Switch Cohort: SD-809 ER n=37 participants at risk Participants who were receiving FDA-approved dosing regimen of tetrabenazine for at least 8 weeks prior to screening, were converted overnight from their existing tetrabenazine regimen to SD-809 ER regimen to achieve targeted steady-state AUC of total (alpha+beta)-HTBZ metabolites that was predicted to be comparable to that of participant's prior tetrabenazine regimen. Participants remained on initial dose of SD-809 ER through Week 1. Dose adjustment was continued through Week 4 to optimize the dose. Dose of SD-809 ER could be adjusted weekly (upward or downward) in increments of 6 mg per day (6 mg/day or 12 mg/day after a total daily dose of 48 mg was reached), based on chorea control and treatment regimen tolerability. Long-term treatment with SD-809 ER at a stable dose (although further dose adjustments were permitted, if clinically indicated) continued until SD-809 ER became commercially available in United States.
Gastrointestinal disorders Intestinal obstruction	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
General disorders Chest discomfort	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
General disorders Sudden cardiac death	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Actinomycotic pulmonary infection	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Appendicitis	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Cellulitis staphylococcal	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Gastroenteritis	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Infection	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Pneumonia	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	5.4% 2/37 • Number of events 2 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Pyelonephritis acute	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Infections and infestations Urinary tract infection bacterial	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Injury, poisoning and procedural complications Fall	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Injury, poisoning and procedural complications Head injury	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Injury, poisoning and procedural complications Hip fracture	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Injury, poisoning and procedural complications Subdural haematoma	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Injury, poisoning and procedural complications Upper limb fracture	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Investigations Weight decreased	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Metabolism and nutrition disorders Dehydration	2.4% 2/82 • Number of events 2 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Metabolism and nutrition disorders Failure to thrive	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Musculoskeletal and connective tissue disorders Rhabdomyolysis	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Penile cancer	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Renal oncocytoma	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Nervous system disorders Encephalopathy	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Nervous system disorders Lethargy	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Nervous system disorders Subarachnoid haemorrhage	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Nervous system disorders Syncope	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Aggression	1.2% 1/82 • Number of events 2 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Anxiety	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Depression	0.00% 0/82 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	2.7% 1/37 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Depression suicidal	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Major depression	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Mental status changes	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Suicidal ideation	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Psychiatric disorders Suicide attempt	2.4% 2/82 • Number of events 2 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Respiratory, thoracic and mediastinal disorders Dyspnoea	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Respiratory, thoracic and mediastinal disorders Pulmonary embolism	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Surgical and medical procedures Spinal fusion surgery	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.
Vascular disorders Deep vein thrombosis	1.2% 1/82 • Number of events 1 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.	0.00% 0/37 • Baseline to follow-up visit (up to approximately 3 years 9 months) Safety population included all participants who received at least 1 dose of study drug.