The mMS is a subscale of the UHDRS total motor score and comprises 13 responses from the 10 items, 4-10 and 13-15, from the UHDRS motor assessment. The items for mMS included dysarthria, tongue protrusion, finger taps (right and left), pronate/supinate hands (right and left), luria - first-hand-palm sequencing, arms rigidity (right and left), body bradykinesia, gait, tandem walking, and retropulsion pull test. Each of these items were rated on a scale of 0 (normal) to 4 (marked impairment). Total score ranged from 0 to 52, with higher scores indicating more severe motor impairment. The last observation carried forward (LOCF) method was used to generate an mMS score for each participant for Week 12 assessment.

The Full Analysis Set (FAS) was defined as all randomized participants who received at least 1 dose of study drug and had undergone at least 1 clinical assessment post randomization. Here, 'Overall number of participants analyzed signifies participants evaluable for this outcome measure.

The UHDRS Motor Assessment comprises 31 responses from the 15 items, where each response is rated on a 5-point scale from 0 (normal) to 4 (maximally abnormal). The Total Motor Score (TMS) is the sum of all the 31 responses with higher scores indicating more severe motor impairment than lower scores.

The FAS was defined as all randomized participants who received at least 1 dose of study drug and had undergone at least 1 clinical assessment post randomization. Here, 'Overall number of participants analyzed signifies participants evaluable for this outcome measure.

The CGI-C was rated by the investigator on a 7-point scale as: 1 = Very much improved; 2 = Much improved; 3 = Minimally improved; 4 = No change; 5 = Minimally worse; 6 = Much worse; and 7 = Very much worse.

The FAS was defined as all randomized participants who received at least 1 dose of study drug and had undergone at least 1 clinical assessment post randomization. Here, 'Overall number of participants analyzed signifies participants evaluable for this outcome measure.

The Stroop test measures the ability to concentrate and ward off distractions. The test consists of three items: (i) colour naming; (ii) word reading; (iii) interference. The word reading test requires participants to read colour words written in black and each response is scored as the number of correct answers made in 45 seconds. Higher scores indicate less severe disease, and an increase in score represents an improvement.

The FAS was defined as all randomized participants who received at least 1 dose of study drug and had undergone at least 1 clinical assessment post randomization. Here, 'Overall number of participants analyzed signifies participants evaluable for this outcome measure.

The total behavioral assessment score is the sum of the 11 products (depressed mood, apathy, low self-esteem/guilt, compulsive behavior, anxiety, irritable behavior, perseverative/obsessive thinking, disruptive/aggressive behavior, suicidal thoughts, delusions, and hallucinations) of frequency and severity symptom scores and excluded the 3 yes/no questions relating to confusion, dementia, and depression. Frequency is rated on a scale of 0 (never or almost never) to 4 (very frequently, most of the time). Severity is rated on a scale of 0 (no evidence) to 4 (severe). Total behavior score ranges from 0 (no impairment) to 88 (severe impairment), with higher scores indicating greater behavioral impairments.

The FAS was defined as all randomized participants who received at least 1 dose of study drug and had undergone at least 1 clinical assessment post randomization. Here, 'Overall number of participants analyzed signifies participants evaluable for this outcome measure.

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 is comprised of 7 items with range 0 (no presence of anxiety or depression) to 3 (severe feeling of anxiety or depression). Total score ranges from 0 to 21 for each subscale where higher scores indicate greater severity of anxiety and depression symptoms. The total HADS score was a composite score summed of all 14 items for a total range of 0-42. Lower change from baseline scores indicate improvement.

The FAS was defined as all randomized participants who received at least 1 dose of study drug and had undergone at least 1 clinical assessment post randomization. Here, 'Overall number of participants analyzed signifies participants evaluable for this outcome measure.

An adverse event (AE) was defined as any change from the participant's baseline (pre-treatment) condition, other than improvement, that did not necessarily have causal relationship with the study drug. TEAEs were defined as adverse events that began after ACR16/placebo administration. AEs included both SAEs and non-serious AEs. A summary of other non-serious AEs and all SAEs, regardless of causality is located in the 'Reported AE section'.

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