Previous studies suggest that genetic factors may play a significant role in determining the amount of weight loss in response to pharmacological treatment. Topiramate is not approved for the treatment of obesity, but reported weight changes in response to treatment with topiramate may be linked to genetic factors. This pharmacogenomics (effect of genetic variation on drug response) study will analyze genetic variations in the DNA extracted from blood samples collected from subjects who were randomized in 1 of 3 previous topiramate studies on obesity and diabetes. The study consist of a screening telephone contact, a single visit to the study site for a blood sample collection (10ml of whole blood) for genetic analyses, and a 24-hour post-sample adverse event-reporting period. The goal of the study is to identify genes that impact percent change in weight and HbA1c from baseline at Week 24 (of the selected studies) and the occurrence of the most frequent central nervous system (CNS)-related adverse events in response to topiramate. The study hypothesis is that there are certain types of genes that are involved in the mode of action of topiramate.

No study drug was administered.