Reduced Exposure Study in Smokers Using THS 2.2 With 5 Days in a Confinement Setting.

Inclusion Criteria: * Subject is Caucasian. * Current healthy smoker as judged by the Principal Investigator. * Subject has smoked at least 10 commercially available non-menthol CCs per day (no brand restrictions) for the last 4 weeks. * Subject has smoked for at least the last 3 consecutive years. * Subject does not plan to quit smoking in the next 3 months. Exclusion Criteria: * As per Investigator judgment, the subject cannot participate in the study for any reason (e.g., medical, psychiatric, and/or social reason). * Subject has received medication within 14 days or within 5 half-lives of the medication (whichever is longer), which has an impact on cytochrome P450 1A2 (CYP1A2) or cytochrome P450 2A6 (CYP2A6) activity. * Female subject is pregnant or breast feeding. * Female subject does not agree to use an acceptable method of effective contraception.