Across the three trials, 2699 patients were randomized to treatment (including 826 to varenicline 1.0 mg twice per day titrated dose, 671 to bupropion, and 814 to placebo). DNA was extracted from blood samples of 1476 consenting individuals (524 varenicline; 440 bupropion; 512 placebo), and primary genetic analysis was performed on 1175 smokers of European ancestry. The genotyped subset was comparable to the overall clinical data set for baseline characteristics and outcomes, including age, gender, race, weight, smoking history, Fagerström Test for Nicotine Dependence, therapeutic smoking cessation response (continuous abstinence from weeks 9 to 12), and adverse event profile (including nausea incidence with varenicline).
