A Study of the Safety of R256918 in Obese Patients

This is a randomized (study drug assigned by chance), double-blind (neither physician nor patient knows the name of the assigned drug), placebo-controlled , parallel-group study with 3 treatment arms, each consisting of 27 obese patients. The study will include 3 phases - pretreatment, double-blind and posttreatment . During the pretreatment phase patients undergo general screening assessments and if eligible, Magnetic Resonance Spectroscopy (MRS) screening will be performed. During the double-blind treatment phase patients will receive dietary counseling, study medication, have urine and blood laboratory tests, a follow up MRS examination and have regular clinic visits for symptoms assessment. The double blind treatment phase ends with an end-of-treatment or early withdrawal visit. A patient withdrawing from the study prior to the end of the 12 week treatment phase will attend an early withdrawal visit, which is the same as the end-of-treatment visit. This visit will include laboratory tests and a follow up MRS examination. Post-treatment: A follow-up evaluation will occur 14 days after the end of treatment. Study visits are scheduled to occur nearly every 14 days following the baseline visit in week 1. The total study duration is approximately 15 weeks. The study will include the following evaluations of safety and tolerability: mean percent change in liver fat content at week 6 and week 12 or at the end of the patients participation in the study, in case of early withdrawal. Safety evaluations for the study will include the monitoring of adverse events, clinical laboratory tests including pregnancy testing, electrocardiograms (ECGs), vital sign measurements (pulse and blood pressure), physical examination, and patient reported assessment of GI symptoms. Special clinical laboratory safety tests will assess blood clotting or coagulation status, essential fatty acid status, lipid-soluble vitamin status: vitamin A, vitamin D, vitamin E, vitamin K, vitamin A/total cholesterol ratio, vitamin E/total cholesterol ratio and liver function tests. 10 mg capsules, 15 mg capsules, or matching placebo capsules taken orally.