Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of PF-06649751 in Parkinson's Disease

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

This study will be an open label, dose escalation study to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of repeated daily quaque die (QD) doses given over 21 days (Day 3 to Day 23) to sequential cohorts of subjects with Parkinson's disease. Each cohort will have 2 study periods. For each cohort, subjects will enter Period 1 and if they meet criteria, approximately 12 subjects will be enrolled into Period 2 and dosed with PF 06649751. Based on results observed in a previous study, Cohorts 1 and 2 will not be conducted. Cohorts 3 - 6 will test doses uptitrated to 5 mg, 15 mg and 25 mg QD. Doses may be modified based on emerging safety, tolerability and PK data, but the maximum daily dose that will be given in any cohort will have PK predictions at steady state that are anticipated to be below toxicokinetic limits. An option for down titration to the previous dose level is available should the investigator consider that an AE is intolerable. Following down titration, a single up titration to the next dose level may be attempted if the subject remains symptom free for at least 48 hrs. Safety, tolerability and PK data of Cohort 3 will be reviewed prior to initiating the dosing in Cohorts 4 and 5. Available safety, tolerability and PK data up to Day 24 of at least 5 subjects from Cohorts 4 will be reviewed prior to initiating the dosing in Cohort 6.

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

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.

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.

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.

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 Change From Baseline in Physical Examination Findings

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.

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.

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

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").

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".

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".

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Clearance obtained after oral dose (apparent oral clearance) is influenced by the fraction of the dose absorbed. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood.

Terminal half-life is the time measured for the plasma concentration of drug to decrease by one half. It was calculated as dividing the natural logarithm to the base e (Log e)*2/k el, where k el is the terminal phase rate constant calculated by a linear regression of the log-linear concentration-time curve.

AUC (0 - inf)= Area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0 - inf). It is obtained from AUC (0 - t) plus AUC (t - inf).

Area under the plasma concentration-time profile from time zero to the time of the last quantifiable concentration (C last).

Volume of distribution is defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug. Apparent volume of distribution after oral dose (Vz/F) is influenced by the fraction absorbed.

Pre-dose on Day 3, 4, 8, 11, 14, 17, 20, Pre-dose, 0.5, 1, 1.5, 2, 4, 8 and 12 hour post-dose on Day 7, 13, 22

Pre-dose on Day 3, 4, 8, 11, 14, 17, 20, Pre-dose, 0.5, 1, 1.5, 2, 4, 8 and 12 hour post-dose on Day 7, 13, 22

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Clearance obtained after oral dose (apparent oral clearance) is influenced by the fraction of the dose absorbed. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood.

Area under the concentration curve from time zero to end of dosing interval (AUCtau), where dosing interval was 12 hours.

Pre-dose on Day 3, 4, 8, 11, 14, 17, 20, Pre-dose, 0.5, 1, 1.5, 2, 4, 8 and 12 hour post-dose on Day 7, 13, 22

Pre-dose on Day 3, 4, 8, 11, 14, 17, 20, Pre-dose, 0.5, 1, 1.5, 2, 4, 8 and 12 hour post-dose on Day 7, 13, 22

Ratio of Accumulation for Area Under the Curve From Time Zero to End of Dosing Interval of PF-06649751

Rac was obtained from AUCtau after last dose divided by AUCtau after first dose, where AUC(tau) = Area under the concentration curve from time zero to end of dosing interval (AUCtau), where dosing interval was 12 hours.

Pre-dose on Day 3, 4, 8, 11, 14, 17, 20, Pre-dose, 0.5, 1, 1.5, 2, 4, 8 and 12 hour post-dose on Day 7, 13, 22

Inclusion Criteria: Clinical diagnosis of idiopathic Parkinson's Disease with at least 2 out of 3 cardinal characteristics (tremor, rigidity, bradykinesia) Mini-Mental State Examination (MMSE) ≥ 25 Hoehn & Yahr Stage I-III inclusive Documented history of end of L-Dopa wearing OFF Cohort 5 only: History of dyskinesia following L-Dopa dosing and Score of at least 2 on Part IV, item 4.2 (functional impact of dyskinesia) of the MDS-UPDRS Exclusion Criteria: Atypical/secondary parkinsonism History of surgical intervention for Parkinson's Disease Dementia/cognitive impairment that can interfere with study assessments

Sohur US, Gray DL, Duvvuri S, Zhang Y, Thayer K, Feng G. Phase 1 Parkinson's Disease Studies Show the Dopamine D1/D5 Agonist PF-06649751 is Safe and Well Tolerated. Neurol Ther. 2018 Dec;7(2):307-319. doi: 10.1007/s40120-018-0114-z. Epub 2018 Oct 25.

https://trialinfoemail.pfizer.com/pages/landing.aspx?StudyID=B7601005&StudyName=Safety%2C%20Tolerability%2C%20Pharmacokinetics%20and%20Pharmacodynamics%20of%20PF-06649751%20in%20Parkinson%60s%20Disease%20