Effects of the D3 Antagonist GSK598809 on Food Reward and Reinforcement

• Functional MRI: Food Processing Task, Food-Stop Signal Task, Food Stroop Task [ Time Frame: 9 weeks ] [ Designated as safety issue: No ]
  
• Behavioural Neurocognitive Task: Visual Probe Task, Stimulus Response Compatibility Task, Pavlovian-Instrumental Task. [ Time Frame: 9 weeks ] [ Designated as safety issue: No ]
  

• Appetite VAS, Bond and Lader VAS, Distress VAS, BIS II, TFEQ, BIS/BAS, BDI-II, Body weight, Metabolic markers: plasma leptin, ghrelin, alpa MSH [ Time Frame: 9 weeks ] [ Designated as safety issue: No ]
  
• PK endpoints: AUC, Cmax, tmax, t1/2 [ Time Frame: 9 weeks ]
  
• Safety and tolerability: adverse events, laboratory values, cardiovascular - blood pressure; heart rate; ECGs, movement disorders, temperature, respiratory rate, serum prolactin, GH and TSH [ Time Frame: 9 weeks ] [ Designated as safety issue: No ]
  

This novel compound is being developed for the treatment of substance dependence and potentially other impulse control disorders.

This is an fMRI study designed to examine the behavioural and physiological effects of a single dose of novel compound on food reward and reinforcement in relation to food seeking behaviour under conditions of fasting, using fMRI, neurocognitive and metabolic endpoints in overweight and obese subjects. These main objectives will be evaluated in the principal part of the study, Part A. The study will also consist of a follow up period of weight management with a dietician where exploratory objectives are considered, Part B.

Part A, will be a single-blind, randomised, placebo controlled, multi-centre, two-period cross-over study. Approximately 24 subjects will be enrolled such that a minimum of 20 subjects complete dosing and critical assessments. All subjects will be required to complete questionnaires, perform a series of behavioural tasks and scanning procedures. Safety and tolerability will be assessed by monitoring subjects for adverse events, vital signs, ECGs, movement disorders (EPS, Akathisia) and laboratory parameters. The pharmacokinetic profile of the compound in this subject population will be determined by blood sampling over a 72 hour period post dosing, in both sessions. Part B will consist of 12 weeks weight management directed by a dietician on an outpatient basis. Subjects will have fortnightly visits with a dietician and at the end of the 12 weeks complete three questionnaires (TFEQ-18R, DBEQ and YBOCS-BE) and have their weight measured to assess weight loss.