A Phase 1b, 2-period, Open Label, Multicenter, Dose Escalation Study To Evaluate The Safety, Tolerability, Pharmacokinetics And Pharmacodynamics Of Pf-06649751 In Subjects With Parkinson's Disease And Motor Fluctuations

Number of Participants With Vital Sign Abnormalities

Time Frame: Baseline up to Day 30

Criteria for vital sign abnormality included supine pulse rate of \<40 beats per minute (bpm) or \>120 bpm, standing pulse rate of \<40 bpm or \>140 bpm, supine and standing systolic blood pressure (SBP) \<90 millimeter of mercury (mmHg), supine and standing diastolic blood pressure (DBP) \<50 mmHg, supine and standing SBP of \>=30 mmHg maximum (max.) increase from baseline (IFB) and and decrease from baseline (DFB) in same posture, supine and Standing DBP of \>=20 mmHg max. increase and decrease from baseline in same posture. Categories in which there was atleast 1 abnormality are reported in this outcome measure.

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

Time Frame: Baseline (Day 1) up to Day 30

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. An SAE is an AE resulting in any of the following outcomes or deemed significant for any other reason: death; Initial or prolonged in-patient hospitalization; life threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent were events between first dose of study drug to the end of study (up to Day 30) that were absent before treatment or that worsened relative to pre-treatment state. AEs included both serious and non-serious adverse events.

Number of Participants With Laboratory Test Abnormalities

Time Frame: Baseline up to Day 30

Criteria for laboratory abnormalities: Hemoglobin (Hgb),hematocrit, red blood cell(RBC) count: less than(\<)0.8\*lower limit of normal(LLN),mean corpuscular Hgb, mean corpuscular volume, mean corpuscular Hgb concentration:\<0.9\*LLN, greater than (\>)1.1\*upper limit of normal(ULN),platelet:\<0.5\*LLN,\>1.75\*ULN,lymphocyte,neutrophil:\<0.8\*LLN, \>1.2\*ULN, basophil, eosinophil, monocyte:\>1.2\*ULN, WBC:\<0.6\*LLN, \>1.5\*ULN;total bilirubin\>1.5\*ULN, aspartate aminotransferase,alanine aminotransferase,alkaline phosphatase:\>3.0\*ULN,total protein,albumin:\<0.8\*LLN,\>1.2\*ULN;blood urea nitrogen,creatinine:\>1.3\*ULN, uric acid\>1.2\*ULN;sodium\<0.95\*LLN,\>1.05\*ULN,potassium,chloride,calcium,bicarbonate:\<0.9\*LLN,\>1.1\*ULN;glucose\<0.6\*LLN,\>1.5\*ULN,urine pH:\<4.5, \>8; urine: WBC, RBC greater than or equal to (\>=)20/high performance field, bacteria: \>20; urobilinogen, urine: glucose, ketone, protein, Hgb, nitrite, leukocyte esterase, bilirubin: \>=1.

Number of Participants With Clinically Significant Change From Baseline in Physical Examination Findings

Time Frame: Baseline up to Day 30

Physical examination included examination of the head, ears, eyes, nose, mouth, skin, heart and lung examinations, lymph nodes, gastrointestinal, musculoskeletal, and neurological systems. The examination assessed the participants for any potential changes in general appearance, the respiratory and cardiovascular systems, as well as towards participant reported symptoms. Findings were considered to be clinically significant based on investigator's decision.

Change From Baseline in Parkinson's Disease Diary For Participants With Motor Fluctuations at Day 13

Time Frame: Baseline, Day 13

According to Parkinson's disease diaries of participants "OFF" time was a time period when the medication no longer providing benefit with regard to mobility, slowness, and stiffness and participants experienced relatively poor overall function with worsening of tremor, rigidity, balance, or bradykinesia. "ON" time was a time period when medication was providing benefit with regard to mobility, slowness, and stiffness. "ON" time was classified as associated with or without troublesome dyskinesia (TD) that interfere with activities of daily living and with or without dyskinesia. "OFF" time and "ON" time with TD were generally considered to be "bad time" with regard to motor function, whereas "ON" time without dyskinesia (WD) and with non- troublesome dyskinesia (NTD) were generally considered to be "good time".

Number of Participants With Categorical Scores on The Columbia Suicide Severity Rating Scale (C-SSRS)

Time Frame: Baseline up to Day 30

The C-SSRS was an interview-based rating scale to systematically assess suicidal ideation and suicidal behavior. C-SSRS assessed whether participant experienced any of the following 1: completed suicide, 2: suicide attempt (response of "yes" on "actual attempt"), 3: preparatory acts toward imminent suicidal behavior ("yes" on "aborted attempt", "interrupted attempt", "preparatory acts or behavior"), 4: any suicidal behavior or ideation, suicidal ideation ("yes" on "wish to be dead", "non-specific active suicidal thoughts", "active suicidal ideation with methods without intent to act or some intent to act, without specific plan or with specific plan and intent"), 7: self-injurious behavior, no suicidal intent ("yes" on "has participant engaged in non-suicidal self-injurious behavior").

Number of Participants With Electrocardiogram (ECG) Abnormalities

Time Frame: Baseline up to Day 30

Criteria for ECG abnormalities: maximum PR interval \>=300 milliseconds (msec) and maximum increase PR interval increase from baseline (IFB): percent change (Pctchg) \>=25 percent (%) for baseline value of \>200 msec and Pctchg\>=50% for baseline value of \<=200 msec for PR interval, maximum QRS interval \>=140 msec and a maximum IFB: Pctchg\>=50%, maximum QTCF interval (Fridericia's Correction) of 450 msec to \<480 msec, 480 msec to \<500 msec or \>=500 msec and a maximum change of \<=30change\<60 or \>=60 msec from baseline.

Number of Participants With Clinically Significant Neurological Examination Abnormality

Time Frame: Baseline up to Day 30

The complete or full neurological examination included assessment of the cranial nerves; muscle strength, tone, cortical drift, abnormal movements; deep tendon reflexes; sensory exam, coordination, gait and station. Higher cortical and motor function was considered part of the complete neurological exam. Findings were considered abnormal as confirmed by a certified neurologist.

Change From Baseline in Parkinson's Disease Diary For Participants With Motor Fluctuations at Day 20

Time Frame: Baseline, Day 20

According to Parkinson's disease diaries of participants "OFF" time was a time period when the medication no longer providing benefit with regard to mobility, slowness, and stiffness and participants experienced relatively poor overall function with worsening of tremor, rigidity, balance, or bradykinesia. "ON" time was a time period when medication was providing benefit with regard to mobility, slowness, and stiffness. "ON" time was classified as associated with or without troublesome dyskinesia (TD) that interfere with activities of daily living and with or without dyskinesia. "OFF" time and "ON" time with TD were generally considered to be "bad time" with regard to motor function, whereas "ON" time without dyskinesia (WD) and with non- troublesome dyskinesia (NTD) were generally considered to be "good time".