A Phase 2, Double-blind Randomized, Sequential Treatment Group, Placebo-controlled Study To Evaluate The Safety, Tolerability And Brain Cortico-striatal Function Of 2 Doses Of Pf-02545920 In Subjects With Early Huntington's Disease

Number of Participants With Treatment-Emergent Adverse Events (AEs) or Serious Adverse Events (SAEs)

时间窗: Baseline up to Day 38

An AE was any untoward medical occurrence without regard to causality in a participant who received study drug. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of treatment and up to the follow-up period that were absent before treatment or that worsened relative to pretreatment state. AEs included both SAEs and non-serious AEs.

Number of Participants With Potentially Clinically Significant Electrocardiogram (ECG) Findings

时间窗: Baseline up to Day 38

ECG parameters included PR interval, QRS complex, and corrected QT interval using Fridericia's formula (QTcF). Criteria for ECG changes meeting potential clinical concern included: PR interval ≥200 milliseconds (msec) or ≥25% increase when baseline is \>100 msec; QRS interval ≥50% increase from baseline when baseline is less than or equal to (\<=)200 msec; and QTcF ≥450 msec or ≥30 msec increase from baseline.

Number of Participants With Change From Baseline in Body Weight of >=7%

时间窗: Baseline up to Day 38

Weight assessment was performed by a study physician or a trained study nurse and was included in the physical examination.

Number of Participants With Suicidal Tendencies (C-SSRS Mapped to C-CASA) at Baseline

时间窗: Baseline (Day 1)

C-SSRS is a participant rated questionnaire to assess suicidal ideation, suicidal behavior, actual attempts (yes or no responses), and intensity of ideation (rated 1=low severity to 5=high severity). Yes/No responses are mapped to Columbia Classification Algorithm of Suicide Assessment (C-CASA) categories: completed suicide, suicide attempt, preparatory acts towards imminent suicidal behavior, suicidal ideation, and self-injurious behavior, or no suicidal intent. A participant could have a yes or no response in more than 1 category.

Number of Participants With Laboratory Abnormalities Meeting the Criteria for Potential Clinical Concern (Without Regard to Baseline Abnormality)

时间窗: Baseline up to Day 38

The following laboratory parameters were analyzed: hematology (hemoglobin, hematocrit, red blood cell \[RBC\] count, platelet count, white blood cell \[WBC\] count, total neutrophils, eosinophils, monocytes, basophils, lymphocytes); blood chemistry (blood urea nitrogen \[BUN\], creatinine, glucose, calcium, sodium, potassium, chloride, total bicarbonate, aspartate aminotransferase \[AST\], alanine aminotransferase \[ALT\], total and direct bilirubin, alkaline phosphatase, uric acid, albumin, and total protein; urinalysis (pH, glucose, protein/albumin, hemoglobin/blood, ketones/acetone, nitrites, leukocyte esterase, microscopy \[if urine dipstick was positive for blood, protein, nitrites or leukocyte esterase\]); others (urine/serum pregnancy test, glycosylated hemoglobin \[HbA1c, if diabetic\]).

Number of Participants With Potentially Clinically Significant Vital Signs Findings

时间窗: Baseline up to Day 38

Vital signs assessment included pulse rate and blood pressure. Criteria for vital sign values meeting potential clinical concern included: supine/sitting pulse rate less than (\<)40 or greater than (\>)120 beats per minute (bpm), standing pulse rate \<40 or \>140 bpm; systolic blood pressure (SBP) of greater than or equal to (\>=)30 millimeters of mercury (mmHg) change from baseline or SBP \<90 mmHg, diastolic blood pressure (DBP) \>=20 mmHg change from baseline or DBP \<50 mmHg.

Categorical Summary of Participants Meeting Stopping Criteria

时间窗: Baseline up to Day 38

Absolute neutrophil count (ANC) and WBC were monitored for safety. Participants with WBC \<3000 but \>=2000 cells/mm\^3 or ANC \<1500 but \>=1000 cells/mm\^3 were to have study treatment suspended. Participants with WBC \<2000 or ANC \<1000 cells/mm\^3 were to be discontinued from study participation.

Change From Baseline in Unified Huntington Disease Rating Scale (UHDRS) Total Motor Score at Day 28

时间窗: Baseline, Day 28

The UHDRS is a clinical rating scale to provide a uniform assessment of the clinical features and course of Huntington Disease. The Total Motor Score (TMS) is 1 of the 6 components of UHDRS, includes 31 items, and ranges from a scale of 0 to 124 (higher scores indicate more severe disease).

Number of Participants With Suicidal Tendencies (C-SSRS Mapped to C-CASA) at Day 7

时间窗: Day 7

C-SSRS is a participant rated questionnaire to assess suicidal ideation, suicidal behavior, actual attempts (yes or no responses), and intensity of ideation (rated 1=low severity to 5=high severity). Yes/No responses are mapped to Columbia Classification Algorithm of Suicide Assessment (C-CASA) categories: completed suicide, suicide attempt, preparatory acts toward imminent suicidal behavior, suicidal ideation, and self-injurious behavior, or no suicidal intent. A participant could have a yes or no response in more than 1 category.

Number of Participants With Suicidal Tendencies (C-SSRS Mapped to C-CASA) at Day 28

时间窗: Day 28

C-SSRS is a participant rated questionnaire to assess suicidal ideation, suicidal behavior, actual attempts (yes or no responses), and intensity of ideation (rated 1=low severity to 5=high severity). Yes/No responses are mapped to Columbia Classification Algorithm of Suicide Assessment (C-CASA) categories: completed suicide, suicide attempt, preparatory acts toward imminent suicidal behavior, suicidal ideation, and self-injurious behavior, or no suicidal intent. A participant could have a yes or no response in more than 1 category.