Study halted prior to enrollment of patients

The purpose of this study is to determine the effect of GSK598809 as compared to placebo in preventing recently-quit smokers from going back to smoking.

The primary objective of this study is to evaluate the efficacy of GSK598809 compared to placebo for the prevention of relapse to smoking in recently abstinent smokers. Subjects who meet eligibility criteria will enter a 4-week open label treatment period during which they will receive nicotine replacement therapy (NRT). Subjects who have achieved at least one week of abstinence during the last week of an open label treatment period will be randomized to either GSK598809 or placebo in the double-blind treatment period and followed for another 12 weeks.

Inclusion Criteria:

• has smoked at least 10 cigarettes a day for at least 2 years
• has had multiple previous attempts to quit smoking and relapsed to smoking.
• generally healthy

Exclusion Criteria:

• cannot be using smokeless tobacco of any type or has tried to quit with medicine.
• does not abuse alcohol or drugs
• certain emotional problems being treated with medications
• pregnant or breast feeding female