A Study to Evaluate the Safety and Tolerability of ABBV-951 in Subjects With Parkinson's Disease (PD)

Study Overview
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Brief Summary
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The purpose of this study was to assess the safety and tolerability of ABBV-951 (Foslevodopa/Foscarbidopa) in participants with Parkinson's disease (PD). This was a single-arm study with preplanned analyses conducted by dose subgroup (Low Dose or High Dose) based on the modal total daily dose (most frequent dose) over the treatment period.

Official Title
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A 52-Week, Open-label, Single-arm Study to Evaluate the Safety and Tolerability of 24-hour Daily Exposure of Continuous Subcutaneous Infusion of ABBV-951 in Subjects With Parkinson's Disease

Conditions
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Parkinson's Disease (PD)

Intervention / Treatment
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* Drug: ABBV-951


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants with diagnosis of idiopathic Parkinson's Disease (PD) that is levodopa-responsive Participants must be judged by the investigator to be inadequately controlled by current therapy, have recognizable/identifiable Off and On states (motor fluctuations), and have a minimum of 2.5 hours of Off time per day Exclusion Criteria: Participant is cognitively impaired and is not able to safely and effectively manage the drug delivery system and the diaries and is not able to adhere to the study Participant is considered by the investigator to be an unsuitable candidate to receive ABBV-951 for any reason

Ages Eligible for Study
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Minimum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ABBV-951 Low Dose Subgroup<br>After a 4-week Optimization Period, participants continued receiving ABBV-951 by continuous subcutaneous infusion (CSCI) during the 48-week Maintenance Period. Participants whose modal total daily dose (most frequent dose) over the entire study was < 2530 mg of Foslevodopa/day were analyzed as the Low Dose Subgroup. | Drug: ABBV-951<br>* Solution for continuous subcutaneous infusion (CSCI)<br>* Other names: Foslevodopa/Foscarbidopa;|
| Experimental: ABBV-951 High Dose Subgroup<br>After a 4-week Optimization Period, participants continued receiving ABBV-951 by continuous subcutaneous infusion (CSCI) during the 48-week Maintenance Period. Participants whose modal total daily dose (most frequent dose) over the entire study was ≥ 2530 mg of Foslevodopa/day were analyzed as the High Dose Subgroup. | Drug: ABBV-951<br>* Solution for continuous subcutaneous infusion (CSCI)<br>* Other names: Foslevodopa/Foscarbidopa;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Adverse Events | An adverse event (AE) is defined as any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product which does not necessarily have a causal relationship with this treatment. The investigator assesses the relationship of each event to the use of study drug. A serious adverse event (SAE) is an event that results in death, is life-threatening, requires or prolongs hospitalization, results in a congenital anomaly, persistent or significant disability/incapacity or is an important medical event that, based on medical judgment, may jeopardize the participant and may require medical or surgical intervention to prevent any of the outcomes listed above. Treatment-emergent adverse events/treatment-emergent serious adverse events (TEAEs/TESAEs) are defined as any event that began or worsened in severity on or after the first dose of study drug. | From first dose of study drug until 30 days following last dose of study drug (up to 480 days) | 
| Number of Participants With Adverse Events of Special Interest | Treatment emergent adverse events of special interest are defined as any adverse event of infusion site infections, infusion site reactions, hallucinations/psychosis, falls and associated injuries, polyneuropathy (peripheral neuropathy), weight loss, or somnolence from the first dose of study drug until 30 days following last dose of study drug. | From first dose of study drug until 30 days following last dose of study drug (up to 480 days) | 
| Number of Participants With Numeric Grade Equal to or Higher Than 5 and With Letter Grade Equal to or Higher Than D on the Infusion Site Evaluation Scale | Skin tolerability was assessed using the Infusion Site Evaluation Scale, a 2-part numeric (0-7) and letter (A-G) grade scale, where a notable skin reaction is defined as a reaction with a numeric grade of 6 or 7 or a letter grade of D, E, F, or G. Any observation of infusion site reaction with irritation criteria > 2 or > C was recorded as an adverse event (AE). | Day 1, Day 2, Week 1, Week 2, Week 3, Week 4, Week 6, Week 13, Week 26, Week 39, and Week 52 | 
| Hematocrit (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Hemoglobin (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Red Blood Cell (RBC) Count (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| White Blood Cell (WBC) Count (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Neutrophils (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Lymphocytes (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Monocytes (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Absolute Platelet Count (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Mean Corpuscular Hemoglobin (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Mean Corpuscular Volume Concentration (MCHC) (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Prothrombin Time (PT) (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Activated Partial Thromboplastin Time (Hematology): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Blood Urea Nitrogen (BUN) (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Creatinine (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Creatine Phosphokinase (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Total Bilirubin (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Serum Alanine Aminotransferase (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Serum Aspartate Aminotransferase (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Serum Lactate Dehydrogenase (LDH) (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Gamma-glutamyl Transferase (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Alkaline Phosphatase (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Sodium (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Potassium (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Calcium (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Inorganic Phosphorus (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Uric Acid (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Total Cholesterol (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Albumin (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Glucose (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Sodium Bicarbonate/CO2 (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Magnesium (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Creatinine Clearance (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Homocysteine (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, and 52 | 
| Vitamin B6 (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, and 52 | 
| Vitamin B12 (Clinical Chemistry): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, and 52 | 
| pH (Urinalysis): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Specific Gravity (Urinalysis): Change From Baseline to End of Study | Samples for clinical laboratory tests were collected at study visits, and a certified central laboratory was used to process the samples and provide results. | Baseline, Weeks 6, 26, 39, and 52 | 
| Orthostatic Systolic Blood Pressure (Vital Signs): Change From Baseline to End of Study | Orthostatic blood pressure was measured after the participant had been supine (lying down with their face up) for at least 5 minutes and then, after the participant had been standing for 2 minutes. When vital sign measurements were scheduled at the same time as a blood collection, vital sign measurements were obtained prior to blood collection. | Baseline, Weeks 1, 6, 26, and 52 (orthostatic and standing); Baseline, Weeks 2, 4, 13, and 39 (supine) | 
| Orthostatic Diastolic Blood Pressure (Vital Signs): Change From Baseline to End of Study | Orthostatic blood pressure was measured after the participant had been supine (lying down with their face up) for at least 5 minutes and then, after the participant had been standing for 2 minutes. When vital sign measurements were scheduled at the same time as a blood collection, vital sign measurements were obtained prior to blood collection. | Baseline, Weeks 1, 6, 26, and 52 (orthostatic and standing); Baseline, Weeks 2, 4, 13, and 39 (supine) | 
| Orthostatic Pulse Rate (Vital Signs): Change From Baseline to End of Study | Orthostatic pulse rate was measured after the participant had been supine (lying down with their face up) for at least 5 minutes and then, after the participant had been standing for 2 minutes. When vital sign measurements were scheduled at the same time as a blood collection, vital sign measurements were obtained prior to blood collection. | Baseline, Weeks 1, 6, 26, and 52 (orthostatic and standing); Baseline, Weeks 2, 4, 13, and 39 (supine) | 
| Electrocardiogram (ECG) Mean Heart Rate: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 
| Electrocardiogram (ECG) Aggregate PR Interval: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 
| Electrocardiogram (ECG) Aggregate QRS Duration: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 
| Electrocardiogram (ECG) Aggregate QT Interval: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 
| Electrocardiogram (ECG) Aggregate QTcB Interval: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 
| Electrocardiogram (ECG) Aggregate QTcF Interval: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 
| Electrocardiogram (ECG) Aggregate RR Interval: Change From Baseline to End of Study | 12-lead electrocardiograms (ECGs) were recorded at study visits after the participant had been supine for at least 5 minutes. Participants were instructed to remain stationary (no talking, laughing, deep breathing, sleeping, or swallowing) for approximately 10 seconds during the ECG recording. When an ECG was recorded at a time near that of a blood collection, the ECG was obtained prior to the blood collection. ECGs on Day 1 were recorded after initiation of the continuous subcutaneous infusion (CSCI) of ABBV-951 prior to the end of the study visit. | Baseline, Day 1 (postdose), Weeks 6 and 52 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Average Daily Normalized Off Time: Change From Baseline to End of Study | Upon awakening and every 30 minutes during their normal waking time, participants recorded their state in the Parkinson's Disease Diary (PD Diary) for 2 consecutive days prior to study visits. Off time is defined as periods of poor mobility, tremor, slowness, and stiffness. The daily On and Off times were normalized to a typical waking day (16 hours) to account for different sleep patterns across participants. When Off was the first morning symptom upon awakening, this was considered morning akinesia in this study. Baseline value is defined as the average of normalized Off time collected over the 2 PD Diary days before the Enrollment visit. Negative changes from Baseline indicate improvement. | Baseline, Weeks 1, 6, 13, 26, 39, and 52 | 
| Average Daily Normalized On Time With Troublesome Dyskinesia: Change From Baseline to End of Study | Upon awakening and every 30 minutes during their normal waking time, participants recorded their state in the Parkinson's Disease Diary (PD Diary) for 2 consecutive days prior to study visits. On time is defined as periods of good motor symptom control. The daily On and Off times were normalized to a typical waking day (16 hours) to account for different sleep patterns across participants. Baseline value is defined as the average of normalized On time with troublesome dyskinesia collected over the 2 PD Diary days before the Enrollment visit. Negative changes from Baseline indicate improvement. | Baseline, Weeks 1, 6, 13, 26, 39, and 52 | 
| Average Daily Normalized On Time Without Troublesome Dyskinesia: Change From Baseline to End of Study | Upon awakening and every 30 minutes during their normal waking time, participants recorded their state in the Parkinson's Disease Diary (PD Diary) for 2 consecutive days prior to study visits. On time is defined as periods of good motor symptom control. The daily On and Off times were normalized to a typical waking day (16 hours) to account for different sleep patterns across participants. Baseline value is defined as the average of normalized On time without troublesome dyskinesia collected over the 2 PD Diary days before the Enrollment visit. Positive changes from Baseline indicate improvement. | Baseline, Weeks 1, 6, 13, 26, 39, and 52 | 
| Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part I Score: Change From Baseline to End of Study | The Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is an investigator-used rating tool to follow the longitudinal course of Parkinson's Disease (PD). Part I assesses the participant's non-motor aspects of experiences of daily living (nM-EDL) with 13 questions. (The numeric score for each question is between 0-4; 0=Normal,1=Slight,2=Mild,3=Moderate,4=Severe). Part I scores range from 0 to 52, with higher scores indicating more severe symptoms of PD. Negative changes from Baseline indicate improvement. | Baseline, Day 2, Weeks 1, 2, 3, 4, 6, 13, 26, 39, and 52 | 
| Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II Score: Change From Baseline to End of Study | The Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is an investigator-used rating tool to follow the longitudinal course of Parkinson's Disease (PD). Part II assesses the participant's motor experiences of daily living (M-EDL) with 13 questions. (The numeric score for each question is between 0-4; 0=Normal,1=Slight,2=Mild,3=Moderate,4=Severe). Part II scores range from 0 to 52, with higher scores indicating more severe symptoms of PD. Negative changes from Baseline indicate improvement. | Baseline, Day 2, Weeks 1, 2, 3, 4, 6, 13, 26, 39, and 52 | 
| Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III Score: Change From Baseline to End of Study | The Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is an investigator-used rating tool to follow the longitudinal course of Parkinson's Disease (PD). Part III assesses the participant's motor examination (including Hoehn and Yahr stage) with 33 questions. (The numeric score for each question is between 0-4; 0=Normal,1=Slight,2=Mild,3=Moderate,4=Severe). Part III scores range from 0 to 132, with higher scores indicating more severe symptoms of PD. Negative changes from Baseline indicate improvement. | Baseline, Day 2, Weeks 1, 2, 3, 4, 6, 13, 26, 39, and 52 | 
| Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part IV Score: Change From Baseline to End of Study | The Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is an investigator-used rating tool to follow the longitudinal course of Parkinson's Disease (PD). Part IV assesses the participant's motor complications with 6 questions. (The numeric score for each question is between 0-4; 0=Normal,1=Slight,2=Mild,3=Moderate,4=Severe). Part IV scores range from 0 to 24, with higher scores indicating more severe symptoms of PD. Negative changes from Baseline indicate improvement. | Baseline, Day 2, Weeks 1, 2, 3, 4, 6, 13, 26, 39, and 52 | 
| Sleep Symptoms as Assessed by the Parkinson's Disease Sleep Scale-2 (PDSS-2) Total Score: Change From Baseline to End of Study | The PDSS-2 consists of 15 questions that evaluate motor and non-motor symptoms at night and upon wakening, as well as disturbed sleep grouped into 3 domains: motor symptoms at night (5 items), Parkinson's Disease (PD) symptoms at night (5 items), and disturbed sleep (5 items). The frequency is assessed for the 15 sleep problems based on a 5-point Likert-type scale (ranging from 0 [never] to 4 [very often] with the exception of Question 1 score ranging from 0 [very often] to 4 [never]). Scores are calculated for each of the 3 domains as well as a total score. The PDSS-2 domain scores range from 0 to 20 and the total score is a sum of the 3 domains and ranges from 0 to 60. Higher scores indicate higher frequency and more severe impact of PD on sleep. Negative changes indicate improvement from Baseline. | Baseline, Weeks 6, 13, 26, 39, and 52 | 
| Quality of Life Assessed by the Parkinson's Disease Questionnaire-39 Items (PDQ-39) Summary Index Score: Change From Baseline to End of Study | The Parkinson's Disease Questionnaire (PDQ-39) is a disease-specific instrument designed to measure aspects of health that are relevant to participants with Parkinson's Disease (PD), and which may not be included in general health status questionnaires. Each item is scored on the following 5-point scale: 0 = never, 1 = occasionally, 2 = sometimes, 3 = often, 4 = always (or cannot do at all, if applicable). Higher scores are consistently associated with more severe symptoms of the disease such as tremors and stiffness. The results can be presented in either domain scores or as a summary index score. The full range of the PDQ-39 summary index score is from 0 (no patient-related symptoms/quality of life unaffected) to 100 (highest patient-related symptoms/low quality of life). Negative changes indicate improvement from Baseline. | Baseline, Weeks 6, 13, 26, 39, and 52 | 
| The EuroQol 5-Dimension Questionnaire (EQ-5D-5L) Quality of Life Summary Index: Change From Baseline to End of Study | The EuroQol 5-dimension questionnaire (EQ-5D-5L) is a standardized non-disease specific instrument for describing and valuing health-related quality of life. The EQ-5D-5L descriptive system comprises 5 dimensions of health (mobility, self -care, usual activities, pain/discomfort, and anxiety/depression) to describe the participant's current health state. Each dimension comprises 5 levels with corresponding numeric scores, where 1 indicates no problems, and 5 indicates extreme problems. The health status is converted to an index value using the country-specific weighted scoring algorithm for the United States (US). The summary index value for the US ranges from a worst score of -0.109 to a best score of 1. An increase in the EQ-5D-5L total score indicates improvement. | Baseline, Weeks 6, 13, 26, 39, and 52 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Parkinson's Disease (PD), ABBV-951, Levodopa/Carbidopa