The purpose of this study is to evaluate the long-term safety and efficacy of VI-0521 compared to placebo for the treatment of overweight and obesity in adults who have completed study OB-303 (NCT00553787) at selected study sites. This is an extension study of protocol OB-303 (NCT00553787).

Inclusion Criteria:

To be eligible for enrollment into this study, subjects must meet all of the following criteria:

• Completion of study OB-303 (NCT00553787) on treatment and compliance with all protocol requirements
• Written informed consent
• Female subjects of childbearing potential must be using adequate contraception, defined as double-barrier methods, stable hormonal contraception plus single barrier method, or tubal ligation. Female subjects are considered to be of childbearing potential unless they have undergone a hysterectomy or bilateral oophorectomy, are ≥55 years of age and experienced spontaneous cessation of menses for at least 1 year, or have a documented follicle-stimulating hormone level ≥40 IU/L
• Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures.

Exclusion Criteria:

Subjects will not be included in the study if they meet any of the following:

• Body mass index ≤22 kg/m2 at the completion of study OB-303
• Off study medication at completion of study OB-303 (NCT00553787) for longer than 4 weeks continuously due to an event-driven holiday, or off study medication with no plans to restart
• Development of any condition during study OB-303 (NCT00553787) that, in the opinion of the investigator, would contraindicate the administration of study medication, affect compliance, interfere with study evaluations, or confound the interpretation of study results
• Participation in a formal weight loss program (including: Weight Watchers and related dietary/lifestyle intervention programs; prepared food programs; prescribed or over the counter weight loss medications; dietary supplement or herbal preparations, teas, or tinctures intended for weight loss; or any supervised fast or very low calorie diet).