Pfizer Inc. (NYSE: PFE) announced today that a post-marketing study assessing the efficacy and safety of varenicline (CHANTIX ®/CHAMPIX ®) in a population of smokers who had made a previous attempt to quit smoking with CHANTIX, and either did not succeed in quitting or relapsed after treatment, met its primary endpoint. CHANTIX significantly increased continuous abstinence rates compared to placebo at weeks nine to 12, the last four weeks of treatment (primary endpoint). The efficacy rates were consistent with findings seen in other CHANTIX clinical trials in smokers who had not been previously treated with CHANTIX. The safety and tolerability profile of CHANTIX in this study was also consistent with previous studies. The most commonly reported treatment-emergent adverse events were nausea, abnormal dreams and headache, with incidence rates similar to previous CHANTIX studies. “Smoking is considered a chronic, relapsing medical condition. The availability of pharmacological treatments has led to a large and growing population of smokers who have made previous quit attempts but were ultimately unsuccessful,” said Steven J. Romano, M.D., senior vice president and medicines development group head, Primary Care Business Unit, Pfizer Inc. “These new data show that, for some adult smokers who had previously taken CHANTIX but either did not quit smoking or relapsed after quitting, another quit attempt with CHANTIX may be fruitful.” Study Background This study was a Phase 4, 12-week, randomized, double-blind, placebo-controlled, multi-center study, which evaluated the efficacy and safety of varenicline tartrate 1 mg BID for smoking cessation in adult subjects, who had made a previous attempt to quit smoking with CHANTIX and either did not succeed in quitting or relapsed after treatment. Patients included in this study had taken CHANTIX for a smoking-cessation attempt in the past (for a total treatment duration of a minimum of two weeks), and at least three months prior to study entry, and had been smoking for at least four weeks.