Smoking Cessation in Subjects With Mild-to-moderate Chronic Obstructive Pulmonary Disease (COPD).

• Number of Subjects With Continuous Abstinence (CA) [ Time Frame: Week 9 through Week 24 and Week 52 ] [ Designated as safety issue: No ]
  Number of subjects who reported no smoking and no use of other nicotine-containing products (treatment phase = through week 12) or tobacco products (non-treatment phase = after treatment phase; follow up through week 52) at each contact (on the NUI) and with end-expiratory exhaled CO measurement less than or equal to 10 ppm from week 9 through week 24 and week 52. CO confirmed in-clinic visit.
• Number of Subjects With Long Term Quit Rate (LTQR) [ Time Frame: Week 24, Week 52 ] [ Designated as safety issue: No ]

  Number of subjects who were responders for the primary endpoint (4-week CQR for Weeks 9 through 12) and who had no more than 6 cumulative days of smoking from Week 12 through the given visit (Week 24 and Week 52).

  CO confirmed in-clinic visit.

• Number of Subjects With 7-Day Point Prevalence of Abstinence [ Time Frame: Week 12, Week 24, Week 52 ] [ Designated as safety issue: No ]
  Number of subjects at given visit (Week 12, Week 24, Week 52) or telephone contact, reported no smoking and no use of other nicotine-containing products (treatment phase) or tobacco products (non-treatment phase) in the last 7 days and with end-expiratory exhaled CO measurement less than or equal to 10 ppm. CO confirmed in-clinic visit.
• Number of Subjects With 4-Week Point Prevalence of Abstinence [ Time Frame: Week 52 ] [ Designated as safety issue: No ]
  Number of subjects at Week 52 visit reporting no smoking and no use of other tobacco products in the last 4 weeks and with end-expiratory exhaled CO measurement less than or equal to 10 ppm.
• Change From Baseline in Pre-bronchodilator and Post-bronchodilator Forced Expiratory Volume in First Second (FEV1) [ Time Frame: Baseline, Week 12, Week 52 ] [ Designated as safety issue: No ]
  Change from baseline in mean FEV1 (forced expiratory volume in the first second of forced exhalation) measured in millimeters (ml) as mean at observation minus baseline value. Directly after pre-bronchodilator measurement, subject inhaled albuterol or salbutamol delivered by metered-dose inhaler (MDI); post-bronchodilator lung function repeated 30 to 45 minutes following administration of albuterol or salbutamol.
• Change From Baseline in Clinical COPD Questionnaire (CCQ) [ Time Frame: Baseline, Week, 12, Week 24, Week 52 ] [ Designated as safety issue: No ]
  Change from baseline: mean at observation minus baseline value. Subject-administered 10-item instrument to systematically assess COPD symptoms (items 1, 2, 5, and 6), functional states (items 7, 8, 9, and 10) and mental states (items 3 and 4); For each domain score = sum of items divided by the number of items; total score = sum of scores divided by 10; range from 0 (very good health) to 6 (extremely poor health). Assessed at each visit based on subject's experience during the week prior to visit.
• Number of Cigarettes Smoked Daily During First 3 Weeks of the 12-Week Treatment Period [ Time Frame: Day 1 through Day 21 ] [ Designated as safety issue: No ]
  Number of cigarettes smoked daily collected during the first 3 weeks of study after randomization using patient smoking diaries.
• Change From Baseline in Inflammatory Biomarkers: C-Reactive Protein (CRP) and Fibrinogen Antigen [ Time Frame: Baseline, Week 12, Week 52 ] [ Designated as safety issue: No ]
  Change from baseline in CRP and Fibrinogen antigen (blood markers of inflammation) calculated as mean at observation minus baseline value; measured as milligrams per deciliter (mg/dl).
• Change From Baseline in Body Weight [ Time Frame: Baseline, Week 52 ] [ Designated as safety issue: No ]
  Change from baseline calculated as mean at observation minus baseline value; body weight measured in kilograms (kg).

This study is to be conducted in subjects with mild-to-moderate COPD who are cigarette smokers with the intent of demonstrating differences in smoking cessation between varenicline and placebo.

• Drug: placebo
  1mg (placebo) by mouth twice daily for 12 weeks (first week is up titration schedule---0.5mg once daily for 3 days, 0.5mg twice daily for 4 days)
• Drug: Varenicline Tartarate
  1 mg by mouth twice daily for 12 weeks (first week is up titration schedule---0.5mg once daily for 3 days, 0.5mg twice daily for 4 days)
  Other Name: Chantix, Champix

• Placebo Comparator: placebo
  Intervention: Drug: placebo
• Experimental: varenicline
  Intervention: Drug: Varenicline Tartarate

• Tashkin DP, Rennard S, Taylor Hays J, Lawrence D, Marton JP, Lee TC. Lung function and respiratory symptoms in a 1-year randomized smoking cessation trial of varenicline in COPD patients. Respir Med. 2011 Nov;105(11):1682-90. Epub 2011 May 31.
• Tashkin DP, Rennard S, Hays JT, Ma W, Lawrence D, Lee TC. Effects of varenicline on smoking cessation in patients with mild to moderate COPD: a randomized controlled trial. Chest. 2011 Mar;139(3):591-9. Epub 2010 Sep 23.
• Ryerson CJ, Berkeley J, Carrieri-Kohlman VL, Pantilat SZ, Landefeld CS, Collard HR. Depression and functional status are strongly associated with dyspnea in interstitial lung disease. Chest. 2011 Mar;139(3):609-16. Epub 2010 Aug 5.

Inclusion Criteria:

• Subjects will be current cigarette smokers who have smoked an average of at least 10 cigarettes per day during the past year and during the month prior to the screening visit.
• mild to moderate COPD confirmed by spirometry
• Subjects must have a clinical diagnosis of COPD.

Exclusion Criteria:

• Subjects who have made a serious attempt to quit smoking in the past 3 months.
• Subjects who have been previously randomized in a study that has included varenicline.