Evaluation of Biomarkers of Exposure in Smokers Switching to a Carbon-Heated Tobacco Product: A Controlled, Randomized, Open-Label 5-Day Exposure Study

Introduction Tobacco harm reduction aims to provide reduced risk alternatives to adult smokers who would otherwise continue smoking combustible cigarettes (CCs). This randomized, open-label, three-arm, parallel-group, single-center, short-term confinement study aimed to investigate the effects of exposure to selected harmful and potentially harmful constituents (HPHCs) of cigarette smoke in adult smokers who switched to a carbon-heated tobacco product (CHTP) compared with adult smokers who continued to smoke CCs and those who abstained from smoking for 5 days. Methods Biomarkers of exposure to HPHCs, including nicotine and urinary excretion of mutagenic material, were measured in 24-hour urine and blood samples in 112 male and female Caucasian smokers switching from CCs to the CHTP ad libitum use. Puffing topography was assessed during product use. Results Switching to the CHTP or smoking abstinence (SA) resulted in marked decreases from baseline to Day 5 in all biomarkers of exposure measured, including carboxyhemoglobin (43% and 55% decrease in the CHTP and SA groups, respectively). The urinary excretion of mutagenic material was also markedly decreased on Day 5 compared with baseline (89% and 87% decrease in the CHTP and SA groups, respectively). No changes in biomarkers of exposure to HPHCs or urinary mutagenic material were observed between baseline and Day 5 in the CC group. Conclusions Our results provide clear evidence supporting a reduction in the level of exposure to HPHCs of tobacco smoke in smokers who switch to CHTP under controlled conditions, similar to that observed in SA. Implications The reductions observed in biomarkers of exposure to HPHCs of tobacco smoke in this short-term study could potentially also reduce the incidence of cancer, cardiovascular and respiratory diseases in those smokers who switch to a heated tobacco product.