CSD170501: Study to Assess Biomarkers of Tobacco Exposure in Smokers During In-Clinic Confinement Switch to an Electronic Cigarette

This will be a two-center, randomized, controlled, switching, open-label, parallel cohort study. The study will compare biomarkers of tobacco exposure from subjects at baseline levels of biomarkers of tobacco exposure after they have switched to one of three electronic cigarettes or abstinence for 5 days.