Effects of Switching to the Tobacco Heating System 2.2 Menthol, Smoking Abstinence, or Continued Cigarette Smoking on Biomarkers of Exposure: A Randomized, Controlled, Open-Label, Multicenter Study in Sequential Confinement and Ambulatory Settings (Part 1)

Impact of heated tobacco products on biomarkers of potential harm and adverse events: a systematic review and meta-analysis

OBJECTIVE

To systematically review available data on the effects of heated tobacco products (HTPs) on biomarkers of potential harm (BoPH) and adverse events, including comparison to cigarettes, e-cigarettes and smoking abstinence.

DATA SOURCES

Web of Science, Scopus, MedRxiv, ClinicalTrials.gov, ICTRP database and HTP manufacturer libraries were searched from January 2010 to December 2024.

STUDY SELECTION

Included studies were interventional clinical trials of any design that measured BoPH or adverse events in adults assigned a marketed HTP and another assigned either cigarettes, e-cigarettes or smoking abstinence.

DATA EXTRACTION

Two reviewers independently extracted data into a predesigned form and assessed risk of bias using Cochrane's Risk of Bias tool version 1.

DATA SYNTHESIS

BoPH data were synthesised using effect direction plots. A random-effects model was used to calculate pooled risk ratios for adverse event data. 40 studies (10 independent, 29 industry-affiliated and 1 of unclear affiliation) were included. Only nine studies lasted longer than 5 days. 19 involved using the intervention just once. Risk of bias was high for 32 studies and unclear for 8. Data on 143 BoPH indicated short-term HTP use had mixed effects compared with cigarettes, e-cigarettes and smoking abstinence. The rate of adverse event reporting was not significantly different between HTP and any comparator group.

CONCLUSIONS

Despite a growing evidence base, significant limitations hinder interpretation of the data, which do not yet provide clear indication of harm or benefit, even compared with cigarettes. Longer, better quality studies independent of tobacco industry funding are needed to determine the health impacts of HTPs.

Impact of Heating Conventional Cigarettes With a Novel Device on Health-Related Biomarkers and Cigarette Use Patterns Among Chinese Adult Smokers Unwilling to Quit: A Pilot Randomized Controlled Trial

INTRODUCTION

We evaluated the impact of heating conventional cigarettes with a novel heated tobacco product (HTP) device on biomarkers and cigarette use patterns in Chinese adult smokers unwilling to quit smoking.

AIMS AND METHODS

In this pilot randomized controlled trial, 50 eligible participants were allocated to either control group (smoking conventional cigarettes) or HTP device group (switching to using heated conventional cigarettes by the HTP device). Participants in the HTP device group went through a 2-day run-in period and then used heated conventional cigarettes exclusively for 5 days, followed by flexible use for 14 days. Five biomarkers of exposure (BoEs) were measured at baseline and on day 7. Thirteen biomarkers of biological effect (BoBEs) were measured at baseline and on day 21. Safety, daily cigarette consumption, craving, withdrawal symptoms, and device acceptability, were assessed.

RESULTS

BoE levels decreased by 26.4 % to 71.4% from baseline in the HTP device group, while BoBE levels did not significantly change in either group. In the HTP group, 56% exclusively used heated conventional cigarettes during the flexible use period, experiencing reduced cravings and withdrawal symptoms, while dual users consumed more cigarettes. Mild to moderate device-related reactions were reported in 36% of users. Satisfaction, taste, and harm reduction belief scores averaged 7.4, 6.6, and 8.7 (out of 10), respectively.

CONCLUSIONS

Switching to heated conventional cigarettes with the HTP device may reduce short-term exposure to smoke toxicants. However, it can lead to increased tobacco use among dual users. Further investigation is needed to confirm these preliminary findings.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (http://www.chictr.org.cn/), ChiCTR2200065055, October 26, 2022.

IMPLICATIONS

This study is the first to evaluate the impact of heating conventional cigarettes with a novel HTP device on health-related biomarkers and cigarette use patterns among Chinese adult smokers. This novel HTP device can directly heat conventional cigarettes without the necessity for specifically designed tobacco products, avoiding the potential additive risks of traditional HTPs. If the results of this study could be further verified by randomized controlled clinical trials with larger sample sizes, this novel HTP device could serve as a short-term harm reduction alternative for smokers unwilling to quit.

Changes in exposure to tobacco-related harmful and potentially harmful constituents among adults who switched completely from smoking cigarettes to use of the JUUL2 system for six days

INTRODUCTION

Adults who switch from smoking cigarettes to use of electronic nicotine delivery systems (ENDS) may reduce their exposure to harmful and potentially harmful constituents (HPHCs). This study assessed changes in exposure to HPHCs, assessed via biomarkers of exposure (BOEs), among adults who switched to a new ENDS product.

METHODS

Adults who smoke cigarettes (N = 89) were randomized to: (1) switch completely to using JUUL2 Virginia Tobacco (N = 24) or Polar Menthol (N = 24); (2) continue smoking usual brand (UB) cigarettes (N = 21); or (3) abstain from all tobacco/nicotine products (N = 20) for 6 d. Changes in exposure to nicotine and 11 other HPHCs from Baseline to Day 6 were compared among study groups.

RESULTS

Changes in nicotine exposure did not significantly differ between JUUL2 and UB Cigarette groups (ps > 0.37). Among participants who switched completely to JUUL2 products, median percent reductions (Day 6-Baseline) in non-nicotine BOEs ranged from 65% to 94%, significantly greater than changes in the UB Cigarette group (ps < 0.001). None of the non-nicotine BOEs significantly differed between the JUUL2 groups and the Abstinence group (ps > 0.025).

CONCLUSIONS

This randomized study demonstrates that adults who switch completely from smoking cigarettes to use of JUUL2 ENDS products substantially reduce their exposure to HPHCs associated with smoking-related diseases.

INTERNATIONAL STANDARD REGISTERED CLINICAL TRIAL NUMBER

ISRCTN27662176.

Assessment of Abuse Liability and Nicotine Pharmacokinetics of glo Heated Tobacco Products in a Randomized, Crossover Study

BACKGROUND AND OBJECTIVE

Heated tobacco products (HTPs) are a class of non-combustible, inhaled tobacco products with the potential to reduce the harm associated with cigarette smoking due to reduced cigarette smoke toxicant exposure. Subjective and nicotine pharmacokinetics measures taken over the course of product use provide a framework for abuse liability (AL) assessment of tobacco and nicotine products as well as information on adoption potential for a new tobacco product, which are important aspects for premarket tobacco product authorization by the US Food and Drug Administration. This study aimed to assess the AL of glo HTPs, operated in either Standard or Boost Modes, compared with high- and low-AL comparators (subjects' usual brand cigarettes and nicotine gum, respectively).

METHODS

Nicotine uptake and pharmacodynamics measures (including subjective and physiological measures) were assessed in a clinical study of 75 healthy adult non-menthol or menthol smokers using an open-label, randomized crossover study design. Comparisons were made between glo HTPs (Standard or Boost Modes) and each of usual brand (UB) cigarettes and nicotine gum to evaluate nicotine exposure and subjective effects measures.

RESULTS

Nicotine uptake, as reflected in the area under the curve (AUC) at 15 and 240 min after product use (AUC0-15 and AUC0-240, respectively) and maximum nicotine concentration (Cmax) were significantly lower for all glo HTPs compared to UB cigarettes, regardless of the glo device mode. AUC0-15 values for glo HTPs ranged from 41.26 to 75.71 ng × min/mL, versus 158.04 to 165.53 ng × min/mL for UB cigarettes. Similarly, AUC0-240 values for glo HTPs ranged from 379 to 596 ng × min/mL, compared to 1123.73 and 1283.37 ng × min/mL for UB cigarettes. The Cmax for glo HTPs ranged from 5.46 to 9.00 ng/mL, whereas UB cigarettes had Cmax values of 16.29 to 16.76 ng/mL. The time to reach maximum nicotine concentration (Tmax) was significantly shorter for glo HTPs (4-5 min) compared to UB cigarettes (6-7 min), except for one variant of glo HTP in Standard Mode. Nicotine gum exhibited a slower nicotine absorption profile, with a Tmax of 45 min and Cmax of 4.60 ng/mL. AUC0-15 and AUC0-240 values for nicotine gum were 6.18 and 5.22 ng × min/mL, and 647.80 and 687.68 ng × min/mL for non-menthol and menthol groups, respectively. Subjective measures indicated that glo HTPs were rated significantly lower than UB cigarettes in terms of product liking, smoking urge reduction, product effects, and intent to use again, but were comparable to nicotine gum.

CONCLUSION

glo HTPs demonstrated lower AL than combustible cigarettes while delivering sufficient nicotine to support product adoption among current smokers. This positions glo HTPs as a potential tool in tobacco harm reduction, offering a less harmful alternative to traditional cigarettes.

TRIAL REGISTRY

Clinical trial ID NCT05114863.

Transformation of the tobacco product market in Japan, 2011-2023

OBJECTIVE

This study updates a previous paper that examined trends in the sale of cigarettes and heated tobacco products (HTPs) in Japan between 2011 and part way through 2019. The current study includes complete unit sales data through 2023.

METHODS

Data on cigarette and HTP sales were obtained from public sources available from the websites and stockholder reports for the Tobacco Institute of Japan, Philip Morris International and Japan Tobacco. We used joinpoint regression using the parametric method to test for trends in both per capita and total sales for the three outcome variables assessed between 2011 and 2023: (1) cigarette sales, (2) HTP sales and (3) combined cigarette and HTP sales. Joinpoint regression identifies changes in trends and estimates the annual per cent change (APC) for each trend segment.

RESULTS

Between 2011 and 2023, per capita and total cigarette sales declined by 52.6% and 52.7%, respectively. From 2011 to 2015, per capita cigarette sales in Japan decreased -1.5% APC; from 2015 to 2018, the decline accelerated to -10.5% APC and continued to fall -7.3% APC between 2018 and 2023. Between 2016 and 2018, per capita HTP sales increased by 149.0% APC, and since 2018, they have increased by 8.1% APC.

CONCLUSION

While many factors may account for the decreased sale of cigarettes in Japan over the past 12 years, the increased sale of HTPs appears to be a factor.

Tobacco use disorder in patients with other mental disorders: a dual disorder perspective from clinical neuroscience

Tobacco smoking is the leading cause of disability and preventable deaths worldwide, but it should be differentiated from tobacco use disorder, which is, according to the Diagnostic and Statistical Manual of Mental Disorders, a bona fide mental disorder. The rapid delivery of nicotine to the brain activates acetylcholine receptors and stimulates the release of dopamine, both systems implicated in other mental disorders. Rates of tobacco use disorder are much higher among people suffering from other mental disorders and these patients find it more difficult to quit. Dual disorders, from a transdiagnostic perspective, identify patients with substance use disorder, in this case tobacco use disorder, and other mental disorders. A dual disorder is a complex clinical condition that is often underdiagnosed, undertreated, and difficult to manage. Appropriate and integrated tobacco use disorder treatment programs for people also suffering from other mental disorders could improve outcomes. Bio-psycho-social approaches to tobacco use disorder include specific biological treatments (e.g., bupropion, varenicline, cytisine, nicotine replacement therapy or deep trans-magnetic stimulation). However, these treatments don't have the same outcomes in patients with dual disorders. Therefore, as in other dual disorders, harm reduction measures, such as vaping nicotine through electronic cigarettes or tobacco replacement therapies should be considered as alternative tools for dual tobacco use disorder management. These clinical considerations emerge from a narrative literature review and expert consensus and will specifically address considerations for changes in clinical practice to improve the treatment of tobacco use disorder and other mental disorders.

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

BACKGROUND

Smoking 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.

METHODS

We 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.

RESULTS

At 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.

CONCLUSION

These 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 REGISTRATION

Clinicaltrials.gov Identifier: NCT0264955. Date of registration: January 7, 2016 https://clinicaltrials.gov/ct2/show/NCT02649556.

A Scoping Review of Behavioural Studies on Heated Tobacco Products

Heated tobacco products (HTPs) are electronic devices that heat tobacco sticks to temperatures much lower than those which cause pyrolysis and combustion in cigarettes. While this electrical heating causes the formation of an inhalable aerosol which contains nicotine, the aerosol from HTPs contains significantly fewer and lower levels of the harmful and potentially harmful chemicals found in cigarette smoke. As a result, HTP use potentially conveys reduced risks to health compared to cigarette smoking. While this relative reduction in individual health risk is becoming clearer, what is less certain is the impact of HTPs on overall population‑level health, taking into account both the potential positive impact on adult smokers who completely switch to using HTPs and any unintended impacts such as use by tobacco non‑users and particularly by youth. The aim of this scoping review was to collate and evaluate the published scientific evidence to date, with a cut‑off of 1 January 2024, investigating the impact of HTPs on population‑level health. This evaluation suggests that HTP use is almost exclusively observed among those with a history of cigarette smoking, and there is a growing body of evidence for the ability of HTPs to provide support for adult smokers to transition away from cigarette smoking, in the absence of any significant "gateway" into tobacco use initiation. Many studies have reported a significant degree of dual use of cigarettes and HTPs, and efforts to assess the reasons for such patterns of use, whether these provide overall exposure reductions, and whether dual use acts as a bridge towards a complete transition away from cigarette smoking, requires further investigation. In addition, correction of the widespread and increasing misperceptions of HTPs among adult smokers is recommended to promote HTP uptake as a potentially less harmful alternative to smoking in this population.

Cigarettes, heated tobacco products and dual use: exhaled carbon monoxide, saliva cotinine and total tobacco consumed by Hong Kong tobacco users

BACKGROUND

Independent studies on exhaled carbon monoxide (CO) and saliva cotinine levels in regular heated tobacco product (HTP) users, and how they compare with conventional cigarette (CC) smokers, are lacking.

METHODS

A total of 3294 current users of CCs, HTPs or electronic cigarettes (ECs) from a household survey and a smoking hotspot survey were classified into seven groups: exclusive users of CCs, HTPs, ECs; dual users of CCs and HTPs, CCs and ECs, HTPs and ECs; and triple users. We measured exhaled CO level using the piCo Smokerlyzer (n=780) and saliva cotinine using NicAlert cotinine test strips (n=620). Among the seven groups, the differences in (1) CO and cotinine levels were examined using Kruskal-Wallis test, and (2) the average daily tobacco consumption in the past 30 days was examined using multivariable linear regression.

RESULTS

Both exclusive and dual users of CCs had a higher CO level than exclusive HTP or EC users (p<0.05). Exhaled CO levels were similar between HTP and EC users, as were saliva cotinine levels among the seven groups. Compared with exclusive CC users, those who also used HTPs or ECs smoked fewer CCs (CCs+HTPs: adjusted coefficient -2.79, 95% CI -3.90 to -1.69; CCs+ECs: -1.34, 95% CI -2.34 to -0.34), but consumed more tobacco sticks equivalent in total (2.79 (95% CI 1.61 to 3.96); 1.95 (95% CI 0.79 to 3.12)).

CONCLUSIONS

HTP or EC use showed lower exhaled CO but similar saliva cotinine levels compared with CC use. Dual users of CCs and HTPs/ECs smoked fewer CCs than exclusive CC users, but consumed more tobacco in total.

A scoping review of the toxicity and health impact of IQOS

This work aims to summarize the current evidence on the toxicity and health impact of IQOS, taking into consideration the data source. On 1 June 2022, we searched PubMed, Web of Science, and Scopus databases using the terms: 'heated tobacco product', 'heat-not-burn', 'IQOS', and 'tobacco heating system'. The search was time-restricted to update a previous search conducted on 8 November 2021, on IQOS data from 2010-2021. The data source [independent, Philip Morris International (PMI), or other manufacturers] was retrieved from relevant sections of each publication. Publications were categorized into two general categories: 1) Toxicity assessments included in vitro, in vivo, and systems toxicology studies; and 2) The impact on human health included clinical studies assessing biomarkers of exposure and biomarkers of health effects. Generally, independent studies used classical in vitro and in vivo approaches, but PMI studies combined these with modeling of gene expression (i.e. systems toxicology). Toxicity assessment and health impact studies covered pulmonary, cardiovascular, and other systemic toxicity. PMI studies overall showed reduced toxicity and health risks of IQOS compared to cigarettes, but independent data did not always conform with this conclusion. This review highlights some discrepancies in IQOS risk assessment regarding methods, depth, and breadth of data collection, as well as conclusions based on the data source.

Impact of More Intense Smoking Parameters and Flavor Variety on Toxicant Levels in Emissions of a Heated Tobacco Product

INTRODUCTION

IQOS HEETS are promoted as reduced-risk alternatives to cigarettes. Although some studies have investigated the chemical composition of HEETS emissions, little is known on whether toxicant levels in such emissions are affected by different puffing parameters and flavor varieties. This has important implications when assessing actual human exposure, since IQOS users develop a specific and personalized puffing behavior and may use different HEETS variants.

METHODS

This study measured the levels of nicotine, total particulate matter, carbonyl compounds, and tobacco-specific nitrosamines (TSNAs) in the emissions of nine differently flavored HEETS and two cigarettes (1R6F and Marlboro Red, MR). Emissions from Yellow HEETS, 1R6F, and MR were collected using the World Health Organization Intense smoking regime and four more intense smoking regimes.

RESULTS

Yellow HEETS aerosol contained lower levels of toxicants compared to 1R6F and MR smoke. More intense smoking regimes increased carbonyl release in cigarette smoke, whereas only higher puff frequency led to lower levels of toxicants in Yellow HEETS aerosol. Some HEETS varieties exhibited higher levels of formaldehyde and TSNAs in their aerosols compared to Yellow HEETS.

CONCLUSIONS

Puff frequency was identified as the only smoking parameter that significantly lowered the release of almost all toxicants in Yellow HEETS, whereas a combination of higher puff volume and puff duration led to increased levels of some carbonyls. Differences in toxicant levels between various commercially available HEETS have important implications when assessing their health impact, as their consumption might induce different toxicant exposure and health effects.

IMPLICATIONS

HEETS release about half as much nicotine and substantially lower levels of toxicants compared to cigarettes. Literature data showed that puffing intensity is increased in cigarette smokers switching to HEETS, maybe in reaction to these lower nicotine levels. Our results show a differential impact of increased puff frequency, puff duration, and puff volume in the release of toxicants from HEETS. Thus, industry-independent studies on puff topography are critical to make choices for the most relevant puffing regime for heated tobacco product regulation. Regulators should consider evaluating the health impact of multiple HEETS varieties, as the tobacco filler composition significantly affects the release of certain toxicants.

Comparison of Publications on Heated Tobacco Products With Conventional Cigarettes and Implied Desirability of the Products According to Tobacco Industry Affiliation: A Systematic Review

INTRODUCTION

Heated tobacco products (HTPs) have been advertised as "reduced-harm" tobacco products compared to conventional cigarettes (CC); however, no direct evidence supporting HTPs being desirable for human health exists. A previous systematic review reported that evidence on HTPs published in 2017 or earlier was primarily drawn from industry-related papers. We aimed to investigate whether tobacco industry-affiliated studies are more likely to conclude that HTPs are more desirable than CC.

METHODS

PubMed and Ichushi-Web were searched up to March 15, 2022, for studies on HTPs published in 2017 or after. We selected studies that assessed any measures of HTPs and CC, including secondary analyses using gray literature in English or Japanese. We excluded review articles except for a meta-analysis that met the aforementioned criteria. Data on the authors' affiliations, grant, conflict of interest, category of research subjects, and interpretation were extracted. Research members in two groups independently assessed the papers; discrepancies were solved by discussion between the groups.

RESULTS

Overall, 134 studies met the criteria. Eighty-seven (64.9%) of them were affiliated with the tobacco industry. Of the 134 studies, 56.3% (49/87) of the industry-affiliated studies versus 19.1% (9/47) of nonindustry-affiliated studies concluded that HTPs were more desirable than CC (p < .01). No study investigated clinically relevant outcomes, such as disease occurrence.

CONCLUSIONS

Publications on HTPs in the biomedical literature from January 2017 to March 2022 were dominated by tobacco industry-affiliated studies. More than half of them concluded that HTPs were more desirable than CC compared to independent studies.

IMPLICATIONS

Tobacco industry advertises HTPs as "reduced-harm" tobacco products compared to CC. HTP users tend to consider HTPs as alternative tobacco products less harmful than CC (ie, products for "harm reduction"). Our results demonstrated that papers written by tobacco industry-affiliated authors concluded that HTPs were more desirable than CC compared to papers by independent authors. However, all their judgments were based on surrogate outcomes. Surrogate outcomes are not necessarily linked to clinically relevant outcomes such as disease occurrence. Further studies on HTPs using clinically relevant outcomes are warranted by independent authors from tobacco industry.

Critical appraisal of interventional clinical trials assessing heated tobacco products: a systematic review

OBJECTIVE

To critically assess the methodological characteristics and quality of interventional clinical trials investigating the effects of heated tobacco products (HTPs).

DATA SOURCES

Web of Science (Core collection and MEDLINE), Scopus, MedRxiv, ClinicalTrials.gov and ICTRP trial databases and transnational HTP manufacturer online publication libraries were searched for clinical trials on HTPs published between January 2010 and April 2022.

STUDY SELECTION

Interventional clinical trials of any design, in which at least one group of adult participants used a currently marketed HTP, were selected by two reviewers with good or very good agreement.

DATA EXTRACTION

Data relating to trial characteristics and effects of intervention on primary outcomes were extracted using a predesigned form. Risk of bias was assessed using Cochrane's Risk of Bias tool v1.

DATA SYNTHESIS

40 trials were included, 29 of which were tobacco industry affiliated. Methodological characteristics, such as registration, design, setting, comparator interventions, participants, outcomes and analyses, varied between trials, though there were few significant differences between industry-affiliated and independent trials. Of the 40 trials, 33 were judged to be at high risk of bias and 6 at unclear risk of bias. Trial findings were not significantly associated with either affiliation or risk of bias.

CONCLUSIONS

The conduct and reporting of HTP interventional clinical trials were poor in many respects and limited to investigating effects of short-term exposure. These trials fall short of what is needed to determine whether HTPs are beneficial to public health, meaning they may not be a sound basis for tobacco control policy decisions.

What Can Current Biomarker Data Tell Us About the Risks of Lung Cancer Posed by Heated Tobacco Products?

INTRODUCTION

Heated tobacco products (HTPs) are marketed as less harmful alternatives to cigarettes, but the lung cancer risk of HTPs is unknown. In the absence of epidemiological data, assessing the risks of HTPs relies on biomarker data from clinical trials. This study examined existing biomarker data to determine what it tells us about the lung cancer risk posed by HTPs.

AIMS AND METHODS

We identified all biomarkers of exposure and potential harm measured in HTP trials and evaluated their appropriateness based on ideal characteristics for measuring lung cancer risk and tobacco use. The effects of HTPs on the most appropriate biomarkers within cigarette smokers switched to HTPs and compared to continued cigarette smoking or cessation were synthesized.

RESULTS

Sixteen out of eighty-two biomarkers (7 exposure and 9 potential harm) measured in HTP trials have been associated with tobacco use and lung cancer, dose-dependently correlated with smoking, modifiable upon cessation, measured within an appropriate timeframe, and had results published. Three of the exposure biomarkers significantly improved in smokers who switched to HTPs and were not significantly different from cessation. The remaining 13 biomarkers did not improve-in some instances worsening upon switching to HTPs-or were inconsistently affected across studies. There were no appropriate data to estimate the lung cancer risk of HTPs in non-smokers.

CONCLUSIONS

The appropriateness of existing biomarker data in assessing lung cancer risk of HTPs, both relative to cigarettes and their absolute risk, is limited. Furthermore, findings on the most appropriate biomarkers were conflicting across studies and largely showed no improvement following a switch to HTPs.

IMPLICATIONS

Biomarker data are fundamental to assessing the reduced risk potential of HTPs. Our evaluation suggests much of the existing biomarker data on HTPs is inappropriate for determining the risk of lung cancer posed by HTPs. In particular, there is a paucity of data on the absolute lung cancer risk of HTPs, which could be obtained from comparisons to smokers who quit and never smokers exposed to or using HTPs. There is an urgent need for further exploration of the lung cancer risks posed by HTPs, via clinical trials and, in the long-term, confirmation of these risks via epidemiological studies. However, careful consideration should be given to biomarker selection and study design to ensure both are appropriate and will provide valuable data.

A Randomized Control Study in Healthy Adult Smokers to Assess Reduced Exposure to Selected Cigarette Smoke Constituents in Switching to the Novel Heated Tobacco Product DT3.0a

This was a randomized, controlled, open-label, confinement study to assess change in exposure to selected cigarette smoke constituents in healthy adult cigarette smokers who switched to using a novel heated tobacco product (direct heating tobacco system, platform 3, generation 3, version a [DT3.0a]). Sixty nonmenthol cigarette smokers were randomized into 1 of the 4 study groups in which subjects switched to a nonmenthol type of tobacco stick used with DT3.0a, switched to a nonmenthol tobacco stick used with an in-market heated tobacco product device (THS), continued to smoke nonmenthol cigarettes, or stopped smoking. Furthermore, 30 menthol cigarette smokers were randomized into 1 of the 2 study groups in which subjects switched to a menthol tobacco stick used with DT3.0a (mDT3.0a) or continued to smoke menthol cigarettes. Fifteen biomarkers of exposure to selected harmful and potentially harmful constituents (HPHCs) were measured during the 5-day exposure period, followed by assessment of nicotine pharmacokinetics with the assigned product. Results indicated that switching to DT3.0a, THS, and mDT3.0a showed significant exposure reductions in most of the selected HPHCs as compared to continuing smoking cigarettes, with reductions being similar in magnitude to reductions observed with smoking cessation. For DT3.0a and mDT3.0a, nicotine pharmacokinetic parameters were not remarkably different from those obtained for cigarettes and the THS except that a longer time to maximum concentration was obtained following use of the mDT3.0a. In conclusion, switching from smoking cigarettes to DT3.0a or THS use reduced exposure to most of the selected HPHCs, and no remarkable differences were observed for the measurements obtained from different flavors of DT3.0a stick.

Metabolic and Other Endocrine Elements with Regard to Lifestyle Choices: Focus on E-Cigarettes

Our objective was to overview recent data on metabolic/endocrine disorders with respect to e-cigarette (e-cig) use. This is a narrative review; we researched English, full-length, original articles on PubMed (between January 2020 and August 2023) by using different keywords in the area of metabolic/endocrine issues. We only included original clinical studies (n = 22) and excluded case reports and experimental studies. 3 studies (N1 = 22,385; N2 = 600,046; N3 = 5101) addressed prediabetes risk; N1 showed a 1.57-fold increased risk of dual vs. never smokers, a higher risk that was not confirmed in N2 (based on self-reported assessments). Current non-smokers (N1) who were dual smokers still have an increased odd of prediabetes (a 1.27-fold risk increase). N3 and another 2 studies addressed type 2 diabetes mellitus (DM): a lower prevalence of DM among dual users (3.3%) vs. cigarette smoking (5.9%) was identified. 6 studies investigated obesity profile (4 of them found positive correlations with e-cig use). One study (N4 = 373,781) showed that e-cig use was associated with obesity in the general population (OR = 1.6, 95%CI: 1.3-2.1, p < 0.05); another (N5 = 7505, 0.82% were e-cig-only) showed that obesity had a higher prevalence in dual smokers (51%) vs. cig-only (41.2%, p < 0.05), while another (N6 = 3055) found that female (not male) e-cig smokers had higher body mass index vs. non-smokers. Data on metabolic syndrome (MS) are provided for dual smokers (n = 2): one case-control study found that female dual smokers had higher odds of MS than non-smokers. The need for awareness with respect to potential e-cig--associated medical issues should be part of modern medicine, including daily anamnesis. Whether the metabolic/endocrine frame is part of the general picture is yet to be determined. Surveillance protocols should help clinicians to easily access the medical background of one subject, including this specific matter of e-cig with/without conventional cigarettes smoking and other habits/lifestyle elements, especially when taking into consideration metabolism anomalies.

The relationship between heated cigarette smoking and blood white blood cell count: a population-based cross-sectional study

OBJECTIVES

Conventional cigarette smoking increases inflammation and white blood cell (WBC) counts. However, there have been limited studies on the relationship between heated cigarette smoking and WBC counts. This study aimed to examine this relationship using nationally representative population-based health data.

STUDY DESIGN

This was a population-based cross-sectional study.

METHODS

The Korea National Health and Nutrition Examination Survey database was used to analyze this relationship. Data related to sex, age, body mass index (BMI), WBC count, and smoking history were obtained from the database. The smoking-related questionnaires included smoking status, smoking type (heated or conventional cigarettes), and smoking amount. The summary statistics of the WBC counts were calculated according to sex, smoking status, and smoking type. In addition, the exposure-response relationship between the smoking amount and WBC count was examined by smoking type, controlling for sex, age, and BMI.

RESULTS

In total, 9747 WBC measurements were used in the analyses. WBC count increased in conventional cigarette smokers, while there was no significant difference in WBC count between heated cigarette smokers and non-smokers. The WBC count showed a positive dose-response relationship with the smoking amount in both conventional and heated cigarette smokers.

CONCLUSIONS

The results confirm that conventional cigarette smoking increases WBC counts. Furthermore, the results suggest that heated cigarette smoking does not lead to a significant increase in WBC counts, although it indicates a potential dose-response relationship with WBC count. Further research with larger sample sizes is needed to confirm whether these results reflect true associations.

Potential Harm of IQOS Smoke to Rat Liver

The Food and Drug Administration has recently classified the IQOS electronic cigarette as a modified-risk tobacco product. However, IQOS cigarettes still release various harmful constituents typical of conventional cigarettes (CCs), although the concentrations are markedly lower. Here, we investigated the damaging effects of IQOS smoking on the liver. Male Sprague Dawley rats were exposed, whole body, 5 days/week for 4 weeks to IQOS smoke (4 sticks/day), and hepatic xenobiotic metabolism, redox homeostasis and lipidomic profile were investigated. IQOS boosted reactive radicals and generated oxidative stress. Exposure decreased cellular reserves of total glutathione (GSH) but not GSH-dependent antioxidant enzymes. Catalase and xanthine oxidase were greater in the exposed group, as were various hepatic CYP-dependent monooxygenases (CYP2B1/2, CYP1A1, CYP2A1, CYP2E1-linked). Respiratory chain activity was unaltered, while the number of liver mitochondria was increased. IQOS exposure had an impact on the hepatic lipid profile. With regard to the expression of some MAP kinases commonly activated by CC smoking, IQOS increased the p-p38/p38 ratio, while erythroid nuclear transcription factor 2 (Nrf2) was negatively affected. Our data suggest that IQOS significantly impairs liver function, supporting the precautionary stance taken by the WHO toward the use of these devices, especially by young people and pregnant women.

An assessment of nicotine pharmacokinetics and subjective effects of the pulze heated tobacco system compared with cigarettes

Nicotine delivery and subjective effects are determinants of the ability of potentially less harmful tobacco products such as heated tobacco products (HTPs) to support adult smokers in switching away from cigarettes, and therefore to support tobacco harm reduction. This open-label, randomised, crossover, clinical study in 24 healthy adult smokers study assessed nicotine pharmacokinetics and subjective effects of the Pulze Heated Tobacco System (HTS; Pulze HTP device and three iD stick variants-Intense American Blend, Regular American Blend and Regular Menthol) compared with subjects' usual brand cigarettes (UBC). Cmax and AUCt were highest for UBC and significantly lower for each Pulze HTS variant. Cmax and AUCt were significantly higher for Intense American Blend compared with Regular American Blend, while AUCt was significantly higher for Intense American Blend compared with Regular Menthol. Median Tmax was lowest (i.e., nicotine delivery was fastest) for subjects' usual brand cigarettes and similar across the iD stick variants, although no between-product differences were statistically significant. All study products reduced urges to smoke; this effect was greatest for cigarettes although this was not statistically significant. Product evaluation scores for each Pulze HTS variant in the domains of 'satisfaction', 'psychological reward' and 'relief' were similar, and lower than those for UBC. These data demonstrate that the Pulze HTS effectively delivers nicotine and generates positive subjective effects, including satisfaction and reduced urge to smoke. This supports the conclusion that the Pulze HTS may be an acceptable alternative to cigarettes for adult smokers while having a lower abuse liability than cigarettes.

Current Evidence on Tobacco Harm Reduction in Pneumology: Interviews with Two Key Opinion Leaders

The negative impact of smoking on the lung is well documented. Cigarette smoke is the cause of 90% of cases of chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema. COPD is a progressive and debilitating condition with morbidity and mortality rates similar to myocardial infarction (MI) and stroke. Despite the widely recognised risks, millions of people continue to smoke, in some cases even after receiving a diagnosis of COPD and despite knowing that the habit will accelerate disease progression. While there is no doubt that smoking cessation is the most important health intervention for all cigarette smokers, it can be challenging. Nicotine addiction, social norms and culture, and the length of time it can take smokers to feel the adverse consequences of the habit all contribute to the high cessation failure rate. However, increasing clinical and epidemiological evidence indicates that for those who are unwilling or cannot stop smoking, harm reduction strategies can help reduce exposure to the harmful chemicals and carcinogens released during tobacco combustion. Electronic devices heat processed tobacco without combusting it to deliver an aerosol containing fewer toxic products or harmful and potentially harmful constituents (HPHC) than cigarette smoke. Clinical evidence to support their use is growing. In Japan, for example, a decrease in hospitalisations due to COPD exacerbation after the introduction of such heat-not-burn (HNB), or tobacco heating systems (THS), has been reported. In this article, Wolfgang Popp, Döbling Doctor’s Center, Privatklinik Döbling, Vienna, Austria, and Klara Szondy, Semmelweis University, Budapest, Hungary, discuss the impact of cigarette smoke on the lung, and how to support smoking cessation in those willing and able to quit smoking. They also explain when strategies that reduce the harmful effects of smoking may be useful, and outline the latest evidence supporting the use of HNB systems.

Part three: a randomized study to assess biomarker changes in cigarette smokers switched to Vuse Solo or Abstinence

Biomarkers of exposure (BoE) can help evaluate exposure to combustion-related, tobacco-specific toxicants after smokers switch from cigarettes to potentially less-harmful products like electronic nicotine delivery systems (ENDS). This paper reports data for one (Vuse Solo Original) of three products evaluated in a randomized, controlled, confinement study of BoE in smokers switched to ENDS. Subjects smoked their usual brand cigarette ad libitum for two days, then were randomized to one of three ENDS for a 7-day ad libitum use period, or to smoking abstinence. Thirteen BoE were assessed at baseline and Day 5, and percent change in mean values for each BoE was calculated. Biomarkers of potential harm (BoPH) linked to oxidative stress, platelet activation, and inflammation were also assessed. Levels decreased among subjects randomized to Vuse Solo versus Abstinence, respectively, for the following BoE: 42-96% versus 52-97% (non-nicotine constituents); 51% versus 55% (blood carboxyhemoglobin); and 29% versus 96% (nicotine exposure). Significant decreases were observed in three BoPH: leukotriene E4, 11-dehydro-thromboxane B2, and 2,3-dinor thromboxane B2 on Day 7 in the Vuse Solo and Abstinence groups. These findings show that ENDS use results in substantially reduced exposure to toxicants compared to smoking, which may lead to reduced biological effects.

Assessment of the exposure to selected smoke constituents in adult smokers using in-market heated tobacco products: a randomized, controlled study

The objectives of this clinical study were to demonstrate a reduction in exposure to selected harmful and potentially harmful constituents (HPHCs) in Japanese healthy adult smokers who switched to four in-market heated tobacco products. Eighty-nine smokers were randomly assigned for five days to one of six study groups: four groups who switched to one of the commercially available heated tobacco products; a group who continued to smoke their own brand of combustible cigarettes (CC); or a group who stopped smoking (SS). Fifteen biomarkers of exposure (BoE) to 14 HPHCs and pyrene were measured at baseline, Day 3 and Day 5 in 24 h urine and breath, under clinical confinement. Product consumption, nicotine uptake and subjective effects were also measured before and after product switching. On Day 5, significant reductions in most BoE relative to the CC group were observed after switching to heated tobacco products. No changes in BoE were observed between baseline and Day 5 in the CC group. Significantly, the magnitude of the reduction in exposure to most of the selected HPHCs observed in the heated tobacco product groups was close to that observed in the SS group.

TOBACCO USE DISORDER AND DUAL DISORDERS Joint statement by the Spanish Psychiatry Society and the Spanish Dual Disorders Society

Tobacco Use Disorder (TUD) is a health problem of the first order in the world population, affecting a vulnerable population, such as people with other mental disorders, whose morbidity and mortality are increased as a result.

“It’s Like Jogging Next to the Highway”: A Qualitative Analysis of the Motivations and Experiences of Single-, Dual-, and Ex-Users of IQOS in The Netherlands

The popularity of heated tobacco products (HTPs) is of concern, as most users are dual users exposed to emissions of both HTPs and conventional cigarettes. Furthermore, HTPs may appeal to young people and non-smokers. This study aims to build intelligence on user experiences in order to inform policy development. We conducted five semi-structured focus group interviews with single-, dual-, and ex-users of the HTP IQOS. The discussions focused on initiation and use, experiences and perception, and knowledge and information needs. We performed a thematic analysis of the transcripts. All users smoked cigarettes and/or roll your own (RYO) tobacco before using HTP. We found that almost all users started using IQOS after being introduced to it by others. Single users successfully quit smoking cigarettes using the IQOS, liked the taste, and experienced physical benefits. Dual users experienced more satisfaction from smoking cigarettes and used the IQOS for specific occasions, such as social situations or in places with smoking bans. All IQOS users described themselves as smokers and considered using the IQOS as an alternative way of smoking. Regulators may consider providing reliable and easily accessible information and regulating points of sale, promotional activities, and product properties such as flavors and devices in order to reduce product attractiveness and discourage use.

Analysis of mainstream emissions, secondhand emissions and the environmental impact of IQOS waste: a systematic review on IQOS that accounts for data source

OBJECTIVE

To highlight the general features of IQOS literature focusing on the chemical analysis of IQOS emissions.

DATA SOURCES

PubMed, Web of Science and Scopus databases were searched on 8 November 2021 using the terms 'heated tobacco product', 'heat-not-burn', 'IQOS' and 'tobacco heating system' with time restriction (2010-2021). The search yielded 5480 records.

STUDY SELECTION

Relevant publications on topics related to IQOS assessment were retrieved (n=341). Two reviewers worked separately and reached agreement by consensus.

DATA EXTRACTION

Data on author affiliation and funding, article type and date of publication were extracted. Publications were categorised depending on their focus and outcomes. Data on IQOS emissions from the chemical analysis category were extracted.

DATA SYNTHESIS

Of the included publications, 25% were published by Philip Morris International (PMI) affiliates or PMI-funded studies. PMI-sponsored publications on emissions, toxicology assessments and health effects were comparable in number to those reported by independent research, in contrast to publications on IQOS use, market trends and regulation. Data on nicotine yield, carbonyl emissions, other mainstream emissions, secondhand emissions and IQOS waste were compared between data sources to highlight agreement or disagreement between PMI-sponsored and independent research.

CONCLUSIONS

Our analysis showed agreement between the data sources on nicotine yield from IQOS under the same puffing conditions. Also, both sources agreed that IQOS emits significantly reduced levels of some emissions compared with combustible cigarettes. However, independent studies and examination of PMI's data showed significant increases in other emissions from and beyond the Food and Drug Administration's harmful and potentially harmful constituents list.

Evolution of tobacco products: recent history and future directions

Declines in cigarette smoking prevalence in many countries and the consolidation of the tobacco industry have prompted the introduction of other forms of nicotine delivery. These include electronic nicotine delivery systems (ENDS), heated tobacco products (HTPs) and oral nicotine products (ONPs). Evolving over time, some of these products now deliver nicotine at levels comparable to cigarettes and may serve as effective substitutes for smokers. However, certain products, especially ENDS like JUUL, have also appealed to youth and non-smokers, prompting concerns about expanding nicotine use (and potentially nicotine addiction). The tobacco industry could shift away from primarily promoting cigarettes to promoting ENDS, HTPs and/or ONPs, though at this time it continues to heavily promote cigarettes in low and middle-income countries. Differing regulatory regimes may place upward and downward pressures on both cigarettes and these newer products in terms of population use, and may ultimately drive the extent to which cigarettes are or are not displaced by ENDS, HTPs and/or ONPs in the coming decade.

Heated tobacco products for smoking cessation and reducing smoking prevalence

BACKGROUND

Heated tobacco products (HTPs) are designed to heat tobacco to a high enough temperature to release aerosol, without burning it or producing smoke. They differ from e-cigarettes because they heat tobacco leaf/sheet rather than a liquid. Companies who make HTPs claim they produce fewer harmful chemicals than conventional cigarettes. Some people report stopping smoking cigarettes entirely by switching to using HTPs, so clinicians need to know whether they are effective for this purpose and relatively safe. Also, to regulate HTPs appropriately, policymakers should understand their impact on health and on cigarette smoking prevalence.

OBJECTIVES

To evaluate the effectiveness and safety of HTPs for smoking cessation and the impact of HTPs on smoking prevalence.  SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group's Specialised Register, CENTRAL, MEDLINE, and six other databases for relevant records to January 2021, together with reference-checking and contact with study authors and relevant groups.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people who smoked cigarettes were randomised to switch to exclusive HTP use or a control condition. Eligible outcomes were smoking cessation, adverse events, and selected biomarkers.  RCTs conducted in clinic or in an ambulatory setting were deemed eligible when assessing safety, including those randomising participants to exclusively use HTPs, smoke cigarettes, or attempt abstinence from all tobacco. Time-series studies were also eligible for inclusion if they examined the population-level impact of heated tobacco on smoking prevalence or cigarette sales as an indirect measure.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking at the longest follow-up point available, adverse events, serious adverse events, and changes in smoking prevalence or cigarette sales. Other outcomes included biomarkers of harm and exposure to toxicants/carcinogens (e.g. NNAL and carboxyhaemoglobin (COHb)). We used a random-effects Mantel-Haenszel model to calculate risk ratios (RR) with 95% confidence intervals (CIs) for dichotomous outcomes. For continuous outcomes, we calculated mean differences on the log-transformed scale (LMD) with 95% CIs. We pooled data across studies using meta-analysis where possible.

MAIN RESULTS

We included 13 completed studies, of which 11 were RCTs assessing safety (2666 participants) and two were time-series studies. We judged eight RCTs to be at unclear risk of bias and three at high risk. All RCTs were funded by tobacco companies. Median length of follow-up was 13 weeks. No studies reported smoking cessation outcomes.  There was insufficient evidence for a difference in risk of adverse events between smokers randomised to switch to heated tobacco or continue smoking cigarettes, limited by imprecision and risk of bias (RR 1.03, 95% CI 0.92 to 1.15; I2 = 0%; 6 studies, 1713 participants). There was insufficient evidence to determine whether risk of serious adverse events differed between groups due to very serious imprecision and risk of bias (RR 0.79, 95% CI 0.33 to 1.94; I2 = 0%; 4 studies, 1472 participants). There was moderate-certainty evidence for lower NNAL and COHb at follow-up in heated tobacco than cigarette smoking groups, limited by risk of bias (NNAL: LMD -0.81, 95% CI -1.07 to -0.55; I2 = 92%; 10 studies, 1959 participants; COHb: LMD -0.74, 95% CI -0.92 to -0.52; I2 = 96%; 9 studies, 1807 participants). Evidence for additional biomarkers of exposure are reported in the main body of the review. There was insufficient evidence for a difference in risk of adverse events in smokers randomised to switch to heated tobacco or attempt abstinence from all tobacco, limited by risk of bias and imprecision (RR 1.12, 95% CI 0.86 to 1.46; I2 = 0%; 2 studies, 237 participants). Five studies reported that no serious adverse events occurred in either group (533 participants). There was moderate-certainty evidence, limited by risk of bias, that urine concentrations of NNAL at follow-up were higher in the heated tobacco use compared with abstinence group (LMD 0.50, 95% CI 0.34 to 0.66; I2 = 0%; 5 studies, 382 participants). In addition, there was very low-certainty evidence, limited by risk of bias, inconsistency, and imprecision, for higher COHb in the heated tobacco use compared with abstinence group for intention-to-treat analyses (LMD 0.69, 95% CI 0.07 to 1.31; 3 studies, 212 participants), but lower COHb in per-protocol analyses (LMD -0.32, 95% CI -1.04 to 0.39; 2 studies, 170 participants). Evidence concerning additional biomarkers is reported in the main body of the review. Data from two time-series studies showed that the rate of decline in cigarette sales accelerated following the introduction of heated tobacco to market in Japan. This evidence was of very low-certainty as there was risk of bias, including possible confounding, and cigarette sales are an indirect measure of smoking prevalence.

AUTHORS' CONCLUSIONS

No studies reported on cigarette smoking cessation, so the effectiveness of heated tobacco for this purpose remains uncertain. There was insufficient evidence for differences in risk of adverse or serious adverse events between people randomised to switch to heated tobacco, smoke cigarettes, or attempt tobacco abstinence in the short-term. There was moderate-certainty evidence that heated tobacco users have lower exposure to toxicants/carcinogens than cigarette smokers and very low- to moderate-certainty evidence of higher exposure than those attempting abstinence from  all tobacco. Independently funded research on the effectiveness and safety of HTPs is needed.  The rate of decline in cigarette sales accelerated after the introduction of heated tobacco to market in Japan but, as data were observational, it is possible other factors caused these changes. Moreover, falls in cigarette sales may not translate to declining smoking prevalence, and changes in Japan may not generalise elsewhere. To clarify the impact of rising heated tobacco use on smoking prevalence, there is a need for time-series studies that examine this association.

Carcinogenic biomarkers of exposure in the urine of heated tobacco product users associated with bladder cancer: A systematic review

To identify biomarkers of exposure present in Heated Tobacco Products (HTPs) users' urine which are associated with bladder cancer and to compare quantitative biomarker levels to those seen in combustible cigarette users. A systematic literature review was conducted in December 2020 with no date limits. Relevant studies that reported quantitative urinary biomarker of exposure in HTP users were included. Biomarkers and their parent compounds were classified by carcinogenicity according to the International Agency for Research on Cancer Monographs and were cross-referenced with the Collaborative on Health and the Environment Toxicant and Disease Database to determine associations with bladder cancer. Our literature search identified 561 articles and 30 clinical trial reports. 11 studies met inclusion criteria. These studies identified 29 biomarkers of exposure present in HTP users' urine, which reflect exposure to 21 unique parent compounds. Of these parent compounds, 14 are carcinogens and 10 have a known link to bladder cancer. HTP users' biomarkers of exposure were present at lower levels than combustible cigarette users but higher than never-smokers. Biomarkers of exposure to bladder carcinogens are present in the urine of HTP users. While levels of these biomarkers appear to be lower than combustible cigarette users, chronic urothelial exposure to bladder carcinogens is concerning and degree of bladder cancer risk remains unknown. Further long-term study is needed to elucidate the bladder cancer risk of HTP use.

Clinical Pharmacology of Electronic Nicotine Delivery Systems (ENDS): Implications for Benefits and Risks in the Promotion of the Combusted Tobacco Endgame

Electronic nicotine delivery systems (ENDS) such as e-cigarettes and heated tobacco products are novel battery-operated devices that deliver nicotine without combustion of tobacco. Because cigarette smoking is sustained by nicotine addiction and the toxic combustion products are mainly responsible for the harmful effects of smoking, ENDS could be used to promote smoking cessation while exposing users to lower levels of toxicants compared with conventional cigarettes. The currently available evidence from clinical and observational studies indicates a potential role of e-cigarettes as smoking cessation aids, although many continue to use e-cigarettes long after quitting smoking. Nicotine and toxicant delivery vary considerably by device and depend on the characteristics of the e-liquid formulation. Because smokers tend to titrate their nicotine intake to maintain their desired pharmacologic effects, device and liquid characteristics need to be considered when using ENDS as an aid to quit smoking. Factors potentially limiting their use are the currently still unknown long-term safety of these products and concerns regarding widespread use among youth. Implications of clinical pharmacology data on ENDS for the cigarette endgame and regulation by the U.S. Food and Drug administration are discussed.

Exposure to Heated Tobacco Products and Adverse Health Effects, a Systematic Review

Heated tobacco products (HTP) are a form of nicotine delivery intended to be an alternative to traditional cigarettes. HTP tobacco products are sold to consumers as a less harmful alternative to traditional cigarettes, both for users and bystanders. The actual impact of HTP on the health of users and its overall impact on public health is still not fully known. A systematic search of the literature was carried out to identify relevant studies published in English from 2015 to February 2021. The following databases were used: PubMed, Scopus, Elsevier and ClinicalKey. 25 studies (independent and sponsored by the tobacco industry) were considered. The analysis of exposure biomarkers and cardiovascular and respiratory biomarkers showed differences between smokers and people using heated tobacco products. Improvements in clinically relevant risk markers, especially cholesterol, sICAM-1, 8-epi-PGF2α, 11-DTX-B2, HDL and FEV1, were observed compared to persistent cigarette smokers. On the other hand, exposure to IQOS has been reported to alter mitochondrial function, which may further exaggerate airway inflammation, airway remodeling and lung cancer. These products have the potential to increase oxidative stress and increase respiratory tract infections by increasing microbial adherence to the respiratory tract. Our review suggests that HTP products may be products with a reduced risk of chronic diseases, including respiratory and cardiovascular diseases and cancer compared to traditional smoking, although in the case of non-smokers so far, they may pose a risk of their occurrence. Research seems to be necessary to assess the frequency of HTP use and its potential negative health effects.

Update on smoking. Alternatives for the management of patients with cardiovascular risk

Smoking is the leading cause of morbidity and mortality worldwide and is clearly involved as a cardiovascular risk factor. Smoking has different effects on the cardiovascular system, such as a decrease in nitric oxide, increased inflammatory response, increased adhesion of pro-atherogenic molecules, lipid disturbances, generation of oxidative stress and endothelial dysfunction as can be shown in different biomarkers modifications. Despite the aids currently available for smoking cessation, many smokers are unwilling or unable to achieve this. So alternative tools with potential harm reduction, such as non-combustion tobacco products, could be an option due to the better results they had shown on cardiovascular risk factors. This has led these devices to be taken into account as a risk-modifying tobacco product according to the FDA.

Systematic review of biomarker findings from clinical studies of electronic cigarettes and heated tobacco products

BACKGROUND

Worldwide adoption of electronic cigarettes (e-cigarettes) and heated tobacco products (HTPs) has increased exponentially over the past decade. These products have been proposed as non-combustible alternatives to traditional tobacco products such as cigarettes and may thus reduce the negative health consequences associated with tobacco smoke. However, the overall health impact and safety of using these products remains unclear. This review seeks to provide an updated summary of available evidence on changes to levels of tobacco-related biomarkers to aid the overall assessment of the consequences of using e-cigarettes and HTPs.

METHODS

A systematic review was conducted through major databases (Medline/PubMed, Scopus, EMBASE) searching for articles directly comparing biomarker levels in humans using e-cigarettes or HTPs and those using combustible cigarettes. We included peer reviewed articles with comparative or longitudinal design and extracted key information for our purpose (type of population, demographics, biomarkers measurements, and health effects). An initial qualitative analysis was performed followed by a summary of findings.

RESULTS

A total of 44 studies were included from initial citations. The vast majority of the literature reported reductions in levels of biomarkers of tobacco smoke exposure (BOE), especially nicotine, MHBMA, 3-HPMA, S-PMA, 1-OHP and NNAL, when using e-cigarettes and HTPs compared to combustible cigarettes. There was a slight tendency toward a larger reduction in these biomarkers levels with the use of e-cigarettes, although direct comparisons between e-cigarettes and HTPs were lacking. There was also a trend toward positive changes in levels of biomarkers of biological effect (BOBE) with the use of e-cigarettes and HTPs.

CONCLUSIONS

A comparison of levels of biomarkers of tobacco-related exposure collected in clinical studies revealed that the use of e-cigarettes and HTPs could lead to a significant reduction in exposure to harmful substances compared to combusted cigarettes. In tandem, the health status of e-cigarettes and HTP users, indexed by levels of biomarkers of biological effect showed potential for improvement compared to smoking. However, larger and longer-term population-based studies are needed to further clarify these findings.

Effect of Switching to the Tobacco Heating System Versus Continued Cigarette Smoking on Chronic Generalized Periodontitis Treatment Outcome: Protocol for a Randomized Controlled Multicenter Study

BACKGROUND

Smoking is a significant risk factor for periodontal disease and tooth loss, as shown in several clinical studies comparing smokers and nonsmokers. Although only a few longitudinal studies have assessed the outcome of periodontal disease after smoking cessation, they indicated that recovery after nonsurgical treatment was more successful in those who had quit smoking. As part of tobacco harm reduction strategies, substituting cigarettes with alternative, less harmful tobacco products is an approach complementary to cessation for smokers who would otherwise continue to smoke. The Tobacco Heating System (THS), developed by Philip Morris International (commercialized as IQOS), is part of the heat-not-burn product category. The IQOS device electrically heats tobacco instead of burning it, at much lower temperatures than cigarettes, thereby producing substantially lower levels of harmful and potentially harmful constituents, while providing the nicotine, taste, ritual, and a sensory experience that closely parallel those of cigarettes. Phillip Morris International has published the results from a broad clinical assessment program, which was established to scientifically substantiate the harm reduction potential of the THS among adult healthy smokers switching to the THS. The program is now progressing toward including adult smokers with smoking-related diseases.

OBJECTIVE

The goal of this study is to demonstrate favorable changes of periodontal endpoints in response to mechanical periodontal therapy in patients with generalized chronic periodontitis who completely switched to THS use compared with continued cigarette smoking.

METHODS

This is a randomized controlled two-arm parallel-group multicenter Japanese study conducted in patients with chronic generalized periodontitis who switch from cigarettes to THS compared with smokers continuing to smoke cigarettes for 6 months. The patients were treated with mechanical periodontal therapy as per standard of care in Japan. The primary objective of the study is to demonstrate the beneficial effect of switching to THS use compared with continued cigarette smoking on pocket depth (PD) reduction in all sites with an initial PD≥4 mm. The secondary objectives include evaluation of other periodontal parameters (eg, clinical attachment level or gingival inflammation) and overall oral health status upon switching to THS. Safety was monitored throughout the study.

RESULTS

In total, 172 subjects were randomized to the cigarette (n=86) or THS (n=86) groups, and all 172 completed the study. The conduct phase of the study is completed, while data cleaning and analyses are ongoing.

CONCLUSIONS

This study is the first to test a heat-not-burn tobacco product in smokers with an already established disease. The results should further strengthen the evidence that switching to THS can significantly reduce the risk of smoking-related diseases if favorable changes in the evolution of chronic generalized periodontitis after mechanical therapy are found when compared with continued cigarette smoking.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03364751; https://clinicaltrials.gov/ct2/show/NCT03364751.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/15350.

Human Biomarker Exposure From Cigarettes Versus Novel Heat-Not-Burn Devices: A Systematic Review and Meta-Analysis

INTRODUCTION

Novel tobacco products require independent research to assess their safety. This study assessed the current literature for trials comparing levels of biomarkers of exposure (BoE) between conventional cigarettes (CC) and heat-not-burn (HNB) devices.

METHODS

Ten databases were searched using terms including: "heat not burn," "iqos," "teeps," "mrtp," "tobacco heating," and "glo" between January 1, 2010 and August 13, 2019. Randomized controlled trials (RCTs) assessing comparative BoE levels in humans using either CC or novel HNB devices were eligible. BoE were tabulated, and differences between the intervention and control groups were analyzed and combined using a random-effects meta-analysis.

RESULTS

Ten nonblinded, RCTs were eligible, involving a total of 1766 participants. Studies regularly reported on 12 BoE (including nicotine). HNB devices assessed included the "IQOS" and "glo" devices and "precursor" (being developed) HNB devices. In comparison to CC, all 12 BoEs assessed were significantly lower for participants assigned to an HNB device. In comparison to smoking abstinence, HNB devices were statistically equivalent for eight BoEs and significantly elevated for four BoEs.

CONCLUSIONS

This review found that the potential for harm to humans is reduced when using HNB devices compared to CC as indicated by significant reductions in BoE levels. Whilst these results support tobacco manufacturer claims of improved safety, the small number of studies included, limited range of BoE assessed, and involvement of the tobacco industry necessitate further independent research to confirm the HNB devices as being a safer alternative to CC.

IMPLICATIONS

This study supports claims made by tobacco manufacturers on the improved safety of HNB tobacco devices in comparison to CC. These novel devices lead to reduced exposure to key biomarkers, which are linked to the health consequences attributed to tobacco use. This has strong implications for international public health as well as further research and policy development relating to the safety aspects and legalities of novel tobacco products.

Reduced levels of biomarkers of exposure in smokers switching to the Carbon-Heated Tobacco Product 1.0: a controlled, randomized, open-label 5-day exposure trial

In addition to smoking cessation, for those who would otherwise continue to smoke, replacing cigarettes with less harmful alternatives can reduce the harms of smoking. Heating instead of burning tobacco reduces, or eliminates, the formation of harmful and potentially harmful constituents (HPHC) that are found in cigarette smoke. The Carbon-Heated Tobacco Product (CHTP), a heat-not-burn tobacco product, mimics the cigarette smoking ritual. This randomized, open-label, two-arm, parallel-group, short-term confinement study tested the hypothesis that the geometric means of the BoExp levels for subjects switching to CHTP 1.0 for 5 days are lower relative to those continuing to smoke cigarettes. Biomarkers of exposure (BoExp), including nicotine, urinary excretion of mutagenic constituents (Ames test), and cytochrome P450 (CYP) 1A2 activity, were measured in blood and/or 24-h urine samples during ad libitum product use. Nicotine exposure remained at similar levels in individuals using CHTP as in those continuing to smoke cigarettes. Switching to CHTP resulted in marked decreases in all other urinary BoExp (56–97%), carboxyhemoglobin (59%), urinary mutagenic constituents, and CYP1A2 activity compared with continued cigarette smoking. Our results provide evidence of decreased exposure to 15 selected HPHCs in smokers switching from cigarettes to exclusive CHTP use.

Trial registration ClinicalTrials.gov: NCT02503254; Date of first registration: 20/07/2015 https://www.clinicaltrials.gov/ct2/show/NCT02503254.

Study protocol Study protocol published at: https://www.clinicaltrials.gov/ProvidedDocs/54/NCT02503254/Prot_000.pdf.

Impact of switching to a heat-not-burn tobacco product on CYP1A2 activity

BACKGROUND

Cigarette smoking induces cytochrome P450 1A2 (CYP1A2) expression and activity, while smoking cessation normalizes the levels of this enzyme. The aim of this publication is to summarize the data on CYP1A2 gene expression and activity in preclinical and clinical studies on the Tobacco Heating System (THS), currently marketed as IQOS® with HEETs®, and to summarize the potential effects on CYP1A2 to be expected upon switching to reduced-risk products (RRPs).

METHODS

We summarized PMI's preclinical and clinical data on the effects of switching from cigarette smoking to THS.

RESULTS

Data from four preclinical mouse and rat studies showed that, upon either cessation of cigarette smoke exposure or switching to THS exposure, the upregulation of CYP1A2 observed with exposure to cigarette smoke reverted close to fresh-air levels. Data from four clinical studies yielded similar results on CYP1A2 activity within a time frame of five days. Furthermore, the effects of switching to THS were similar to those seen after smoking cessation.

CONCLUSIONS

Because smoking cessation and switching to either electronic cigarettes or THS seem to have similar effects on CYP1A2 activity, the same measures taken for patients treated with narrow therapeutic index drugs that are metabolized by CYP1A2 and who quit smoking should be recommended for those switching to RRPs.

Comparing the preclinical risk profile of inhalable candidate and potential candidate modified risk tobacco products: A bridging use case

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Heated tobacco products tested for reduced exposure and reduced risk properties.

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Bridging opportunities for nonclinical results from two heated tobacco products.

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Similarly reduced impact on apical and molecular endpoints relative to cigarettes.

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Evidence evaluated along a “causal chain of events leading to disease” (CELSD).

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Representative assays along CELSD could support nonclinical substantial equivalence.

Cigarette smoking causes major preventable diseases, morbidity, and mortality worldwide. Smoking cessation and prevention of smoking initiation are the preferred means for reducing these risks. Less harmful tobacco products, termed modified-risk tobacco products (MRTP), are being developed as a potential alternative for current adult smokers who would otherwise continue smoking. According to a regulatory framework issued by the US Food and Drug Administration, a manufacturer must provide comprehensive scientific evidence that the product significantly reduces harm and the risk of tobacco-related diseases, in order to obtain marketing authorization for a new MRTP. For new tobacco products similar to an already approved predicate product, the FDA has foreseen a simplified procedure for assessing “substantial equivalence”. In this article, we present a use case that bridges the nonclinical evidence from previous studies demonstrating the relatively reduced harm potential of two heat-not-burn products based on different tobacco heating principles. The nonclinical evidence was collected along a “causal chain of events leading to disease” (CELSD) to systematically follow the consequences of reduced exposure to toxicants (relative to cigarette smoke) through increasing levels of biological complexity up to disease manifestation in animal models of human disease. This approach leverages the principles of systems biology and toxicology as a basis for further extrapolation to human studies. The experimental results demonstrate a similarly reduced impact of both products on apical and molecular endpoints, no novel effects not seen with cigarette smoke exposure, and an effect of switching from cigarettes to either MRTP that is comparable to that of complete smoking cessation. Ideally, a subset of representative assays from the presented sequence along the CELSD could be sufficient for predicting similarity or substantial equivalence in the nonclinical impact of novel products; this would require further validation, for which the present use case could serve as a starting point.

Favorable Changes in Biomarkers of Potential Harm to Reduce the Adverse Health Effects of Smoking in Smokers Switching to the Menthol Tobacco Heating System 2.2 for 3 Months (Part 2)

INTRODUCTION

Tobacco Heating System (THS) 2.2, a candidate modified-risk tobacco product, aims at offering an alternative to cigarettes for smokers while substantially reducing the exposure to harmful and potentially harmful constituents found in cigarette smoke.

METHODS

One hundred and sixty healthy adult US smokers participated in this randomized, three-arm parallel group, controlled clinical study. Subjects were randomized in a 2:1:1 ratio to menthol Tobacco Heating System 2.2 (mTHS), menthol cigarette, or smoking abstinence for 5 days in confinement and 86 subsequent ambulatory days. Endpoints included biomarkers of exposure to harmful and potentially harmful constituents (reported in our co-publication, Part 1) and biomarkers of potential harm (BOPH).

RESULTS

Compliance (protocol and allocated product exposure) was 51% and 18% in the mTHS and smoking abstinence arms, respectively, on day 90. Nonetheless, favorable changes in BOPHs of lipid metabolism (total cholesterol and high- and low-density cholesterol), endothelial dysfunction (soluble intercellular adhesion molecule-1), oxidative stress (8-epi-prostaglandin F2α), and cardiovascular risk factors (eg, high-sensitivity C-reactive protein) were observed in the mTHS group. Favorable effects in other BOPHs, including ones related to platelet activation (11-dehydrothromboxane B2) and metabolic syndrome (glucose), were more pronounced in normal weight subjects.

CONCLUSIONS

The results suggest that the reduced exposure demonstrated when switching to mTHS is associated with overall improvements in BOPHs, which are indicative of pathomechanistic pathways underlying the development of smoking-related diseases, with some stronger effects in normal weight subjects.

IMPLICATIONS

Switching to mTHS was associated with favorable changes for some BOPHs indicative of biological pathway alterations (eg, oxidative stress and endothelial dysfunction). The results suggest that switching to mTHS has the potential to reduce the adverse health effects of smoking and ultimately the risk of smoking-related diseases. Switching to mTHS for 90 days led to reductions in a number of biomarkers of exposure in smokers, relative to those who continued smoking cigarettes, which were close to those observed when stopping smoking (reported in our co-publication, Part 1). Initial findings suggest reduced levels of 8-epi-prostaglandin F2α and intercellular adhesion molecule 1, when switching to mTHS for 90 days. These changes are comparable to what is observed upon smoking cessation. In normal weight subjects, additional favorable changes were seen in 11-dehydrothromboxane B2, fibrinogen, homocysteine, hs-CRP, percentage of predicted forced expiratory volume in 1 second, systolic blood pressure, diastolic blood pressure, glucose, high-density lipoprotein, apolipoprotein A1, and triglycerides.

TRIAL REGISTRATION

NCT01989156.

What Is Accounting for the Rapid Decline in Cigarette Sales in Japan?

This study describes how trends in the sale of cigarettes in Japan between 2011 and 2019 correspond to the sales of heated tobacco products (HTPs) that were introduced into the Japanese market in late 2015. Data used for this study come from the Tobacco Institute of Japan and Philip Morris International. The findings show that the accelerated decline in cigarette only sales in Japan since 2016 corresponds to the introduction and growth in the sales of HTPs.

Gendered factors for heated tobacco product use: Focus group interviews with Korean adults

INTRODUCTION

Since June 2017, heated tobacco products (HTPs) have been on sale in Korea, comprising approximately 11.8% of total tobacco sales in April 2019. This research illuminates hitherto unexplored gendered factors influencing the use of HTPs.

METHODS

The participants for the focus group interviews (FGI) were recruited among those who use or have used HTPs. Participants were separated into six groups (a total of 38 persons: 20 men and 18 women). Each FGI, lasting for two hours, was audio-recorded and transcribed, and subsequently coded to conduct a content analysis using NVivo V12.

RESULTS

Both male and female participants shared the same opinion that HTPs were ‘less smelly’ and that despite their significant merit, HTPs had slightly different usages and places of use. First, male participants used them to avoid family members’ pressure to quit smoking, and female participants used them to avoid the stigma associated with female smoking. Second, men tended to use HTPs indoors, mostly in non-smoking areas, while women used them outdoors, mainly in the streets. Both genders were dissatisfied with the taste of HTPs and often used them in combination with combustible cigarettes (CCs). In terms of taste, dual use, absence of smoking cessation, and perception of harm, no definite gendered difference was found. Almost half of the participants considered HTPs to be less harmful than cigarettes, while others contended that they were equally harmful. Many agreed that there was no strong correlation between the use of HTPs and smoking cessation.

CONCLUSIONS

Since HTPs have the potential to weaken motivating factors for smoking cessation in both male and female users, an understanding of their characteristics with gendered factors is beneficial to establishing policies to prevent the spread of HTP use and increase the overall rate of smoking cessation.

In vitro long-term repeated exposure and exposure switching of a novel tobacco vapor product in a human organotypic culture of bronchial epithelial cells

Next‐generation tobacco products and nicotine delivery systems such as heat‐not‐burn tobacco products and electronic cigarettes, the usage of which is expected to have a beneficial impact on public health, have gained popularity over the past decade. However, the risks associated with the long‐term use of such products are still incompletely understood. Although the risks of these products should be clarified through epidemiological studies, such studies are normally performed based on each product category, not product‐by‐product. Therefore, investigation of the risk on a product‐by‐product basis is important to provide specific scientific evidence. In the current study, we performed the 40‐day repeated exposure of in vitro human bronchial epithelial tissues to cigarette smoke (CS) or vapor from our proprietary novel tobacco vapor product (NTV). In addition, tissue samples exposed to CS were switched to NTV or CS exposure was stopped at 20 days to reflect a situation where smokers switched to NTV or ceased to smoke. All tissue samples were assessed in terms of toxicity, inflammation and transcriptomic alterations. Tissue samples switched to NTV and the cessation of exposure samples showed recovery from CS‐induced damage although there was a time‐course difference. Moreover, repeated exposure to NTV produced negligible effects on the tissue samples while CS produced cumulative effects. Our results suggest that the use of NTV, including switching to NTV from cigarette smoking, has fewer effects on bronchial epithelial tissues than continuing smoking.

We carried out the 40‐day repeated exposure of in vitro bronchial epithelial tissues to cigarette smoke (CS) or vapor from novel tobacco vapor product (NTV) and intermediate switching from CS exposure to NTV exposure. Long‐term exposure to NTV resulted in negligible effect on the tissues. Moreover, the tissues that intermediately switched to NTV exposure showed recovery from CS‐induced damage similar to exposure cessation. These results implied that exposure to NTV showed few effects on bronchial epithelial tissues.

Chemical Analysis and Simulated Pyrolysis of Tobacco Heating System 2.2 Compared to Conventional Cigarettes

Introduction

Tobacco Heating System 2.2 (THS 2.2, marketed as iQOS) is a heat-not-burn (HNB) tobacco product that has been successfully introduced to global markets. Despite its expanding market, few independent and systematic researches into THS 2.2 have been carried out to date.

Methods

We tested a comprehensive list of total particulate matter (TPM), water, tar, nicotine, propylene glycol, glycerin, carbon monoxide, volatile organic compounds, aromatic amines, hydrogen cyanide, ammonia, N-nitrosamines, phenol, and polycyclic aromatic hydrocarbon under both ISO and HCI regimes. We also simulated pyrolysis of THS 2.2 heating sticks and made comparisons with conventional cigarette tobacco fillers using comprehensive gas chromatography-mass spectrometry (GC × GC-MS) to determine whether the specially designed ingredients help reduce harmful constituents.

Results

Other than some carbonyls, ammonia, and N-nitrosoanabasine (NAB), the delivered releases from THS 2.2 were at least 80% lower than those from 3R4F. Tar and nicotine remained almost the same as 3R4F. Interestingly, the normalized yield of THS 2.2 to 3R4F under the HCI regime was lower than that under the ISO regime.

Conclusions

THS 2.2 delivered fewer harmful constituents than the conventional cigarette 3R4F. Simulated pyrolysis results showed that the lower temperature instead of specially designed ingredients contributed to the distinct shift. In particular, if smoking machines are involved to evaluate the HNB products, smoking regimes of heat-not-burn tobacco products should be carefully chosen.

Implications

To our knowledge, few independent studies of HNB products have been published. In this paper, a comprehensive list of chemical releases was tested systematically and compared to those from 3R4F. Although THS 2.2 generates lower levels of harmful constituents, the nicotine and tar levels were almost identical to 3R4F.The results should be discussed carefully in the future when assessing the dual-use with other conventional cigarettes, nicotine dependence of HNB products, etc. This study also suggests that regulatory agencies should pay attention to the smoking regimes that are adopted to evaluate HNB tobacco products.

In vitro mutagenicity of gas-vapour phase extracts from flavoured and unflavoured heated tobacco products

The in vitro mutagenic and genotoxic potential of Heated Tobacco Products (HTPs) has already been studied with the particulate phase and reported previously. This study has been designed to complement the in vitro assessment of the HTP and to determine whether the inclusion of potential flavourings would alter the in vitro response by testing the other phase of the aerosol, the gas-vapour phase (GVP). Both flavoured and unflavoured Neostik GVP samples did not show any sign of mutagenic activity in the Ames test but induced a mutagenic response in the mouse lymphoma assay (MLA), however, these responses were significantly less than those of the reference cigarette, 3R4F. The results demonstrated that GVP emissions of this HTP did not induce either new qualitative or quantitative mutagenic hazards compared to 3R4F, as assessed by the Ames test (no new responsive strains) and MLA (a lower mutagenic response), respectively. A statistical comparative analysis of the responses showed that the addition of flavourings that may thermally decompose under the conditions of use did not add to the in vitro baseline responses of the unflavoured Neostik.

Heated Tobacco Products: A Review of Current Knowledge and Initial Assessments

The health risks of tobacco smoking have been documented in numerous studies and smoking rates have declined in developed countries over the last 50 years. Today, we know that cigarette smoking is the major cause of preventable deaths due to tobacco smoke induced diseases. As a consequence of an increased awareness of smoking-related health risks, heated tobacco products (HTPs) are marketed as reduced toxicant alternatives to conventional tobacco products. Manufacturers claim that levels of toxicants and hazardous compounds are significantly reduced, implying that inhalation of the modified aerosol is less harmful compared to conventional cigarettes. In this manuscript, previous assessments of HTPs are briefly summarized, including a short discussion on challenges with the adaption of standard analytical methods used for tobacco smoke. The reliability of analytical data is important for risk assessment approaches that are based on reduced toxicant exposure. In order to assess a putative reduction of health risks, an integrated study design is required that should include clinical studies and epidemiology data. One manufacturer applied for a classification as a Modified Risk Tobacco Product (MRTP) in the United States, based on extensive toxicological studies that have also been published. However, data are not yet sufficient for a reliable assessment or recognition of putatively reduced health risks. Challenges regarding a classification in Europe are also discussed briefly in this review.

Heat-not-burn tobacco products: a systematic literature review

OBJECTIVE

To review peer-reviewed evidence on heat-not-burn tobacco products (HnB), their secondhand emissions and use by humans; to identify differences between independent and industry-funded studies.

DATA SOURCES

Medline, Embase, PsycINFO, ProQuest, Scopus and Web of Science databases were searched up to 6 November 2017 for studies on HnB published after December 2009; reference lists were screened and other researchers contacted, yielding 637 records.

STUDY SELECTION

Thirty-one publications on HnB secondhand emissions (n=16) or use by humans (n=15) were selected by two reviewers with excellent agreement (k=0.75).

DATA EXTRACTION

Data on authors' affiliations, HnB products, secondhand emissions and human exposure were extracted by one reviewer. Two reviewers assessed the quality of experimental HnB studies using the Effective Public Health Practice Project tool.

DATA SYNTHESIS

Twenty out of 31 studies were affiliated with tobacco industry. Studies on secondhand emissions varied by methodology, products and comparators. Compared with cigarettes, HnB delivered up to 83% of nicotine and reduced levels of harmful and potentially harmful toxicants by at least 62% and particulate matter by at least 75%. Experimental HnB use studies were limited to one product, reductions of human exposure to toxicants varied between 42% and 96%. HnB use suppressed urges to smoke, but participants rated HnB less satisfying than cigarettes. While limited by methodological heterogeneity, findings were largely similar for independent and industry-funded studies.

CONCLUSIONS

Studies on HnB secondhand emissions and human use were heterogeneous and largely affiliated with the manufacturers. HnB exposed users and bystanders to toxicants, although at substantially lower levels than cigarettes.

Assessing the lung cancer risk reduction potential of candidate modified risk tobacco products

Smoking is the major cause of lung cancer. While the risk of lung cancer increases with the number of cigarettes smoked and the duration of smoking, it also decreases upon smoking cessation. The development of candidate modified risk tobacco products (cMRTP) is aimed at providing smokers who will not quit with alternatives to cigarettes that present less risk of harm and smoking-related disease. It is necessary to assess the risk reduction potential of cMRTPs, including their potential to reduce the risk of lung cancer. Assessing the lung cancer risk reduction potential of cMRTPs is hampered by (i) the absence of clinical risk markers that are predictive of future lung cancer development, (ii) the latency of lung cancer manifestation (decades of smoking), and (iii) the slow reduction in excess risk upon cessation and a fortiori upon switching to a cMRTP. It is, therefore, likely that only long-term epidemiology will provide definitive answers to this question and allow to first verify that a cMRTP reduces the risk of lung cancer and if it does, to quantify the reduction in excess lung cancer risk associated with a cMRTP. For this to be possible, the cMRTP would need to be available in the market and used exclusively by a large portion of current smokers. Here, we propose that a mechanism-based approach represents a solid alternative to show in a pre-market setting that switching to a cMRTP is likely to significantly reduce the risk of lung cancer. This approach is based on the causal chain of events that leads from smoking to disease and leverages both non-clinical and clinical studies as well as the principles of systems toxicology. We also discuss several important challenges inherent to the assessment of cMRTPs as well as key aspects regarding product use behavior.

A Meta-Analysis of the Performance of a Blood-Based Exposure Response Gene Signature Across Clinical Studies on the Tobacco Heating System 2.2 (THS 2.2)

As part of emerging tobacco harm reduction strategies, modified risk tobacco products (MRTP) are being developed to offer alternatives that have the potential to reduce the individual risk and population harm compared with smoking cigarettes for adult smokers who want to continue using tobacco and nicotine products. MRTPs are defined as any tobacco products that are distributed for use to reduce harm or the risk of tobacco-related disease associated with commercially marketed tobacco products. One such candidate MRTP is the Tobacco Heating System (THS) 2.2, which does not burn tobacco but instead heats it, thus producing significantly reduced levels of harmful and potentially harmful constituents compared with cigarettes. The clinical assessment of candidate MRTPs requires the development of exposure-response markers to distinguish current smokers from either nonsmokers or former smokers with high specificity and sensitivity. Toward this end, a whole blood-derived gene signature was previously developed and reported. Four randomized, controlled, open-label, three-arm parallel group reduced exposure clinical studies have been conducted with subjects randomized to three arms: switching from cigarettes to THS 2.2, continuous use of cigarettes, or smoking abstinence. These clinical studies had an investigational period of 5 days in confinement, which was followed by an 85-day ambulatory period in two studies. Here we tested the previously developed blood-derived signature on the samples derived from those clinical studies. We showed that in all four studies, the signature scores were reduced consistently in subjects who either stopped smoking or switched to THS 2.2 compared with subjects who continued smoking cigarettes.

[Systematic analysis of the scientific literature on heated tobacco]

INTRODUCTION

The tobacco industry (TI) reports that heated tobacco reduces risk of tobacco use and will replace cigarettes. An analysis of the scientific literature was conducted in order to enlighten professionals and decision-makers.

METHOD

After a Medline query in February 2018, a systematic analysis was conducted.

RESULTS

Of the 100 papers published in 2008-2018, 75 have authors affiliated or linked to TI. Emissions contain gases, droplets and solid particles, so are smokes. The main products are: THS2.2 (Iqos®) which heats mini-cigarettes at 340°C, the THP1.0 (Glo®) which heats at 240°C sticks delivering about half as much nicotine, Ploom® which uses reconstituted tobacco microcapsules heated at 180°C. Under the experimental conditions, there is a reduction of toxic emissions and biological effects, but the expected risk reduction is not demonstrated. Symptoms related to passive smoking are described. The 4 epidemiological articles report that heated tobacco is used in 10 to 45% of cases by non-smokers and demonstrate the effectiveness of TI promotion campaigns. Thus, the THS2.2 is more a gateway to smoking (20%) than an exit door (11%); moreover, it is not expected risk reduction among the 69% who are mixed users.

CONCLUSIONS

While reducing emissions is documented, reducing the risk to the smoker who switches to heated-tobacco remains to be demonstrated. On the other hand, the worsening of the global tobacco risk related to the promotion of the products by the TI is anticipated, justifying that the authorities take the appropriate measures to control the promotion of heated tobacco.