Impact of switching from cigarette smoking to tobacco heating system use on biomarkers of potential harm in a randomized trial

BackgroundSmoking cessation reduces the risk of developing smoking-related diseases. Although smoking prevalence has declined, many continue smoking cigarettes. Switching completely to smoke-free alternatives like the Tobacco Heating System (THS) 2.2-a heated tobacco product for which there is evidence demonstrating significantly reduced formation and exposure to harmful chemicals compared to cigarettes-has the potential to reduce the harm caused by continuing to smoke cigarettes.MethodsWe conducted a 6-month clinical study (NCT02396381) with a 6-month extension (NCT02649556), initially randomizing 984 adult smokers to continue smoking or switch to THS (non-mentholated), of which 672 continued into the extension study. Endpoints were evaluated at baseline and at 3, 6, and 12 months. We longitudinally assessed biomarkers of potential harm (BoPHs) known to be reversible upon smoking cessation as indicators of pathways involved in the pathogenesis of cardiovascular or respiratory diseases and carcinogenicity. The need to cough and safety profile were also assessed. Impact on eight key BoPHs was used as a proxy to evaluate harm reduction potential.ResultsAt 12 months, comparison of BoPH levels between the predominant THS use and cigarette smoking groups showed a positive effect in favor of switching, partially or in full, to THS.ConclusionThese results provide additional evidence of the harm reduction potential of THS for smokers who would otherwise continue smoking, but they need to be verified in long-term confirmatory studies.Clinical trial registrationClinicaltrials.gov Identifier: NCT0264955. Date of registration: January 7, 2016 https://clinicaltrials.gov/ct2/show/NCT02649556