A Randomized Controlled Trial Evaluating the Efficacy of E-Cigarette Use for Smoking Cessation in the General Population: E3 Trial Design

Background: Smoking cessation improves morbidity and mortality among smokers who achieve long-term abstinence. Many smokers are using electronic cigarettes (e-cigarettes) to attempt to quit, despite a lack of data concerning their efficacy and safety for smoking cessation. Methods: The Evaluating the Efficacy of E-Cigarette use for Smoking Cessation (E3) trial is a multicentre randomized controlled trial (NCT02417467) with a treatment period of 12 weeks and follow-up of 52 weeks. A total of 376 participants motivated to quit smoking were enrolled at 17 Canadian centres (November 2016 to September 2019). Participants were randomized (1:1:1) to 1 of 3 treatment arms: nicotine e-cigarettes, non-nicotine e-cigarettes, or no e-cigarettes. All groups received individual counselling. Treatment allocation was double-blind for the e-cigarette groups. The trial includes follow-ups by telephone at weeks 1, 2, 8, and 18, and clinic visits at weeks 4, 12, 24, and 52. The primary endpoint is to compare nicotine e-cigarettes to counselling alone in terms of biochemically validated point-prevalence smoking abstinence at 12 weeks; the primary endpoint was changed from 52 weeks after early termination (77% of targeted enrollment) due to a prolonged delay in e-cigarette manufacturing. The secondary objectives are to examine the efficacy of nicotine and non-nicotine e cigarettes in terms of point-prevalence and continuous smoking abstinence, and reduction in daily cigarette consumption at all follow- ups through week 52, and to describe the occurrence of adverse events. Conclusion: The E3 trial will provide regulators, health care pro- fessionals, and smokers with important information about the efficacy and safety of e-cigarettes for smoking cessation.