 - Current or previous smokers with a cigarette smoking history of 10 pack-years. number of pack years number of cigarettes per day 20 x number of years smoked e.g., 10 pack-years is equal to 20 cigarettes per day for 10 years, or 10 cigarettes per day for 20 years. Former-smokers are defined as subjects who have discontinued smoking for 6 months prior to Visit 1. Subjects who decide to stop smoking at Visit 1 will not be eligible for participation in the study. 