This Study Will Investigate the Effect of Single Oral Doses of Retosiban on Cardiac Repolarization, With Moxifloxacin as a Positive Control in Healthy Volunteers.

Study Overview
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Brief Summary
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This will be a randomized, placebo-controlled, single, oral dose, four-way Williams crossover study design in healthy male and female subjects. The study consists of screening (28 days), treatment (1 day/dosing session) and follow-up (7 to 14 days) period and the total duration of study participation for each subject will be approximately 9 weeks. Each subject will participate in 4 dosing sessions separated by a minimum 7-day washout period. All subjects will receive single doses of retosiban 100 mg, (treatment A) retosiban 800 mg (Treatment B), moxifloxacin 400 mg (Treatment C) and placebo (Treatment D) in one of the four treatment sequences (ABDC, BCAD, CDBA, DACB) following a Williams design Twelve-lead ECGs and continuous Holter monitoring, clinical laboratory safety tests, vital sign measurements, physical examinations, adverse event reports, and pharmacokinetic samples will be collected throughout the study. In each study period, cardiac conduction will be measured using a 24-hour continuous 12-lead Holter monitor from the morning of Day 1 (dosing) until the morning of Day 2.

Official Title
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A Randomized, Placebo-Controlled, Double-Blind, Four-way Crossover Study to Assess the Effect of Single Oral Doses of Retosiban on Cardiac Repolarization, With Moxifloxacin as a Positive Control in Healthy Volunteers

Conditions
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Obstetric Labour, Premature

Intervention / Treatment
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* Drug: Retosiban 100 mg
* Drug: Retosiban 800 mg
* Drug: Placebo
* Drug: Moxifloxacin 400 mg


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Male or female between 18 and 45 years of age inclusive, at the time of signing the informed consent A female subject is eligible to participate if she is of: child-bearing potential and agrees to use the contraception methods from time of consent until until 48 hours post last dose; Non-childbearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea. Females on hormone replacement therapy (HRT) and whose menopausal status is in doubt will be required to use the contraception methods if they wish to continue their HRT during the study. Otherwise, they must discontinue HRT to allow confirmation of post-menopausal status prior to study enrollment. For most forms of HRT, at least 2 to 4 weeks should elapse between the cessation of therapy and the blood draw; this interval depends on the type and dosage of HRT. Following confirmation of their post-menopausal status, they can resume use of HRT during the study without use of a contraceptive method. Healthy as determined by a responsible and experienced physician, based on a medical evaluation including medical history, physical examination, laboratory tests and cardiac monitoring. A subject with a clinical abnormality or laboratory parameters outside the reference range for the population being studied may be included only if the Investigator and the GlaxoSmithKline (GSK) Medical Monitor agree that the finding is unlikely to introduce additional risk factors and will not interfere with the study procedures. Body weight (greater than or equal to) >=50 kg and body mass index (BMI) within the range 19 to 29.9 kg/m^2 Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form No significant abnormality on 12-lead ECG at screening, including the following specific requirements: ventricular rate >=40 beats per minute, PR interval less than or equal to (<=) 210 miliseconds (msec), Q waves less than (<)30 msec, QRS interval to be >=60 msec and <120 msec; the waveforms must enable the QT interval to be clearly defined; QTcB or QTcF interval must be <450 msec ALT, alkaline phosphatase and bilirubin <=1.5xULN (isolated bilirubin greater than (>) 1.5x upper limit of normal (ULN) is acceptable if bilirubin is fractionated and direct bilirubin <35%) Exclusion Criteria: A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening. A supine blood pressure that is persistently higher than 140/90 millimeters of mercury (mmHg). A supine mean heart rate outside the range 40 to 90 beats per minute (bpm). Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones). A positive pre-study drug/alcohol screen. A positive test for Human Immunodeficiency Virus (HIV) antibody. History of regular alcohol consumption within 6 months of the study defined as: an average weekly intake of >14 drinks for males or >7 drinks for females. One drink is equivalent to 12 g of alcohol: 12 ounces (360 ml [milliliters]) of beer, 5 ounces (150 ml) of wine or 1.5 ounces (45 ml) of 80 proof distilled spirits. The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer). Exposure to more than four new chemical entities within 12 months prior to the first dosing day. History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation. Where participation in the study would result in donation of blood or blood products in excess of 500 ml within a 56 day period. Pregnant females as determined by positive serum human chorionic gonadotropin (hCG) test at screening or prior to dosing. Lactating females. Unwillingness or inability to follow the procedures outlined in the protocol. Urinary cotinine levels indicative of smoking or history or regular use of tobacco- or nicotine-containing products within 6 months prior to screening. Unable to refrain from consumption of red wine, seville oranges, grapefruit or grapefruit juice and/or pummelos, exotic citrus fruits, grapefruit hybrids or fruit juices from 7 days prior to the first dose of study medication. History or presence of any medically significant disease, or any disorder that would introduce additional risk or interfere with the study procedures or outcome. In particular, a family history of QT prolongation, of early or sudden cardiac death or of early cardiovascular disease. Use of prescription or non-prescription drugs, including vitamins, herbal and dietary supplements from 14 days before screening until the follow-up visit unless in the opinion of the Investigator and sponsor the medication will not interfere with the study or compromise subject safety. Serum calcium, magnesium or potassium levels outside the reference range History of sensitivity to quinolone antibiotics or components thereof or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Retosiban 100 mg<br>Each subject will be randomized to single dose of retosiban 100 mg in one of the four treatment sequences. | Drug: Retosiban 100 mg<br>* Subjects will be administered with single dose of one moxifloxacin placebo tablet, one 100 mg tablet of retosiban and 7 retosiban matched placebo tablets<br>|
| Experimental: Retosiban 800 mg<br>Each subject will be randomized to single dose of retosiban 800 mg in one of the four treatment sequences | Drug: Retosiban 800 mg<br>* Subjects will be administered with single dose of one moxifloxacin placebo tablet and eight 100 mg tablets of retosiban<br>|
| Placebo Comparator: Placebo<br>Each subject will be randomized to single dose of matching placebo in one of the four treatment sequences | Drug: Placebo<br>* Subjects will be administered with one moxifloxacin placebo tablet and eight retosiban matched placebo tablets<br>|
| Active Comparator: Moxifloxacin 400 mg<br>Each subject will be randomized to single dose of moxifloxacin 400 mg in one of the four treatment sequences | Drug: Moxifloxacin 400 mg<br>* Subjects will be administered with one 400 mg moxifloxacin tablet and eight retosiban matched placebo tablets<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in QT duration corrected for heart rate by Fridericia's formula (QTcF) interval at each timepoint for retosiban as compared with time-matched placebo | Single 12-lead electrocardiograms (ECG)s will be obtained at each timepoint during the study using an ECG machine that automatically calculates corrected QT interval (QTc) interval. An average of at least 3 12-lead Holter ECG replicates per time point. Change = 12-lead ECG reading at each timepoint minus the baseline 12-lead ECG reading. | Baseline (Day 1-pre-dose) and 1 hour [hr], 8 hrs, 12 hrs , 24 hrs (Day 2) post-dose and Day 7 per dosing session. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in QTcF, QT duration corrected for heart rate by Bazett's formula (QTcB), and QT interval corrected for heart rate (QTci) /QTciL interval at each timepoint for 100 mg and 800 mg retosiban as compared with time-matched placebo | Single 12-lead ECGs will be obtained for subjects receiving 100 mg and 800 mg retosiban at each timepoint during the study using an ECG machine that automatically calculates QTc interval. An average of at least 3 12-lead Holter ECG replicates per time point. Change = 12-lead ECG reading at each timepoint minus the baseline 12-lead ECG reading | Baseline (Day 1-pre-dose) and 1 hour [hr], 8 hrs, 12 hrs , 24 hrs (Day 2) post-dose and Day 7 per dosing session. | 
| Change from baseline in QTcF, QTcB, and QTci/QTciL interval at each timepoint for moxifloxacin as compared with time-matched placebo | Single 12-lead ECGs will be obtained for subjects receiving moxifloxacin at each timepoint during the study using an ECG machine that automatically calculates QTc interval. An average of at least 3 12-lead Holter ECG replicates per time point. Change = 12-lead ECG reading at each timepoint minus the baseline 12-lead ECG reading. | Baseline (Day 1-pre-dose) and 1 hour [hr], 8 hrs, 12 hrs , 24 hrs (Day 2) post-dose and Day 7 per dosing session. | 
| Plasma concentrations of retosiban and GSK2847065 | Pharmacokinetic data will include plasma concentration of retosiban and GSK2847065 | Day 1 (pre-dose), 0.25 hr, 0.5 hr, 0.75 hr, 1 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, 10 hr, 12 hr, 18 hr post-dose and Day 2 per dosing session. | 
| Maximum observed concentration (Cmax) for retosiban and GSK2847065 | Pharmacokinetic data will include Cmax of retosiban and GSK2847065 | Day 1 (pre-dose, 0.25 hr, 0.5 hr, 0.75 hr, 1 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, 10 hr, 12 hr, 18 hr post-dose) and Day 2 per dosing session | 
| Time to maximum concentration (tmax) for retosiban and GSK2847065 | Pharmacokinetic data will include tmax of retosiban and GSK2847065 | Day 1 (pre-dose, 0.25 hr, 0.5 hr, 0.75 hr, 1 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, 10 hr, 12 hr, 18 hr post-dose) and Day 2 per dosing session | 
| Area under the concentration-time curve over the dosing interval (AUC(0-τ)) for retosiban and GSK2847065 | Pharmacokinetic data will include AUC0-τ of retosiban and GSK2847065 | Day 1 (pre-dose, 0.25 hr, 0.5 hr, 0.75 hr, 1 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr, 10 hr, 12 hr, 18 hr post-dose) and Day 2 per dosing session | 
| Maximal change from baseline for QTcF and QTcB | Single 12-lead ECGs will be obtained using an ECG machine that automatically calculates QTc interval. An average of at least 3 12-lead Holter ECG replicates per time point. Maximal Change from baseline = maximum 12-lead ECG reading at each timepoint minus the baseline 12-lead ECG reading | Baseline (Day 1-pre-dose) and 1 hour [hr], 8 hrs, 12 hrs , 24 hrs (Day 2) post-dose and Day 7 per dosing session | 
| Change from baseline for other cardiac electrophysiological parameters: QT, QRS, RR, PR and ventricular rate at each timepoint | Single 12-lead ECG will be obtained using an ECG machine that automatically calculates the heart rate and measures PR, QRS, QT and QTc intervals. Change from baseline for other cardiac electrophysiological will be calculated as: other cardiac electrophysiological parameters at each timepoint minus baseline value | Baseline (Day 1-pre-dose) and 1 hour [hr], 8 hrs, 12 hrs , 24 hrs (Day 2) post-dose and Day 7 per dosing session | 
| Safety and tolerability of retosiban as assessed by change from baseline in 12-lead ECGs | Single 12-lead ECG will be obtained using an ECG machine that automatically calculates the heart rate and measures PR, QRS, QT and QTc intervals | Day 1 (pre-dose, 1 hr, 8 hr, 12 hr post-dose), Day 2 and Day 7 | 
| Safety and tolerability of retosiban as assessed by change from baseline in systolic and diastolic blood pressure | Vital sign measurements will be done in supine position and will include systolic and diastolic blood pressure | Day 1 (pre-dose, 1 hr, 2 hr, 4 hr, 6 hr, 8 hr, 10 hr, 12 hr, 18 hr post-dose), Day 2 and Day 7 | 
| Safety and tolerability of retosiban as assessed by change from baseline in pulse rate | Vital sign measurements will be done in supine position and will include pulse rate. | Day 1 (pre-dose, 1 hr, 2 hr, 4 hr, 6 hr, 8 hr, 10 hr, 12 hr, 18 hr post-dose), Day 2 and Day 7 | 
| Safety and tolerability of retosiban as assessed number of adverse events | Safety and tolerability parameters will include recording of AEs, throughout the study | 9 weeks | 
| Safety and tolerability of retosiban as assessed by change from baseline in clinical laboratory tests | Clinical laboratory assessments will include hematology, clinical chemistry, routine urinalysis and additional parameters | Day -1 and Day 2 and Day 7 |