A Study of VI-0521 for the Treatment of Obstructive Sleep Apnea / Hypopnea Syndrome in Obese Adults

Inclusion Criteria: * Obese adults 30 - 65 years old (inclusive); * Women of child-bearing potential must be using adequate contraception; * BMI between 30 and 40 kg/m2 (inclusive); * Diagnosis of OSA syndrome with Apnea/Hypopnea Index (AHI) of 15 or greater; * Unwilling or unable to comply with CPAP treatment; Exclusion Criteria: * Known allergy or hypersensitivity to phentermine or topiramate; * Sleep disorder other than OSA syndrome; * Women who are pregnant, breast feeding, or intend to become pregnant during the study; * Presence of unstable angina or heart failure corresponding to NYHA functional class III or IV; * History of myocardial infarction or coronary revascularization within the past year; any history of stroke; * Presence of any clinically significant abnormality on electrocardiogram; * Use of any prescription CNS stimulants; * History of cholecystitis or cholelithiasis unless treated by cholecystectomy; * History of glaucoma or any past or present use of medications to treat increased intraocular pressure; * Weight gain or loss of greater than 5 kg, use of a very low-calorie diet, or participation in a formal weight loss program (investigational or otherwise) within the past 3 months; * Previous bariatric surgery; * Shift workers or any subjects with a circadian rhythm disorder; * Professional drivers or commercial pilots; * History of nephrolithiasis; * More than one lifetime episode of major depression; * History of bipolar disorder, obsessive compulsive disorder, borderline personality disorder, psychotic depression, schizophrenia, schizoaffective disorder, or any other psychotic disorder; history of any psychiatric hospitalization; * History of a seizure disorder; concurrent use of any anticonvulsant drug (other than assigned study drug);