Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 5: 8-Day randomized clinical trial in Japan

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.

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.

Acute exposures to e-cigarettes and heat-not-burn products reported to the Czech Toxicological Information Centre over a 7-year period (2012-2018)

E-cigarettes and heat-not-burn cigarettes (HNBC) present new health risks due to their rising popularity, high content of nicotine and serious adverse effects. The objective of the study was to analyse the cases of acute exposure to e-cigarettes, e-liquids and HNBC products containing nicotine that led to toxicological consultations at our poisons control centre during a 7-year period (2012-2018) and identify the categories of special concern that require further investigation and intervention. The demographic, toxicological and clinical data were analysed by descriptive statistics. Poisoning severity score (PSS) was estimated. From 119 229 consultations, 148 cases concerned acute exposure to e-cigarettes. Children and adolescents were exposed in 91 (61%) cases, including exposure of neonates and infants in 54 (36%) cases. The main route of exposure was ingestion in 129 (87%), inhalation in nine (6%), ocular in six (4%) and intravenous administration in three (2%) cases. The source of exposure was the cartridge with e-liquid (107; 72%), refillable tank in 29 (20%) and HNBC refill in nine (6%) cases. The reason for exposure was accidental in 110 (74%), incorrect application of the device in 10 (7%), abuse in six (4%), suicide attempt in six (4%) and other/unknown in 16 (11%) cases. The dose estimation was severe/lethal in 6 (4%), toxic in 53 (36%), low-to-moderate in 35 (24%) and unknown in 54 (36%) cases. Vomiting was observed in 38 (26%) patients; 72% of patients were hospitalised. In symptomatic cases, 41 patient had PSS 1, 12 patients had PSS 2, and one patient had PSS 3. Activated charcoal was applied in 57 (39%) patients, and symptomatic treatment was recommended in 75 (51%) patients. Cases of unintentional exposure of children demonstrate the need for preventive risk reduction measures.

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)

Introduction

The menthol Tobacco Heating System 2.2 (mTHS) is a newly developed candidate modified-risk tobacco product intended to reduce exposure to the harmful and potentially harmful constituents (HPHCs) of conventional cigarette (CC) smoke. This study examined the impact of switching to mTHS on biomarkers of exposure to HPHCs relative to menthol CCs (mCCs) and smoking abstinence (SA).

Methods

In this three-arm, parallel-group study, 160 Japanese adult smokers (23–65 years; smoking ≥10 mCCs per day) were randomized to mTHS (n = 78), mCC (n = 42), or SA (n = 40) for 5 days in confinement and 85 days in ambulatory settings. Endpoints included biomarkers of exposure to HPHCs, human puffing topography, safety, and subjective effects of smoking measures.

Results

After 5 days of product use, the concentrations of carboxyhemoglobin, 3-hydroxypropylmercapturic acid, monohydroxybutenyl mercapturic acid, and S-phenylmercapturic acid were 55%, 49%, 87%, and 89% lower (p < .001), respectively, in the mTHS group than in the mCC group. Other biomarkers of exposure (measured as secondary endpoints) were 50%–94% lower in the mTHS group than in the mCC group on day 5. These reductions in the mTHS group were maintained at day 90, similar to the SA group. Switching to mTHS was associated with changes in human puffing topography (shorter puff intervals and more frequent puffs). The urge-to-smoke and smoking satisfaction levels on day 90 were similar in the mTHS and the mCC groups.

Conclusion

Switching from mCCs to mTHS significantly reduced exposure to HPHCs relative to continuing smoking mCCs with concentrations similar to those observed following SA in Japanese adult smokers.

Implications

This randomized study compared the impact of switching to a modified-risk tobacco product candidate mTHS on biomarkers of exposure to HPHCs of cigarette smoke relative to continuing smoking cigarettes or abstaining from smoking in sequential confinement and ambulatory settings. The study showed that switching to mTHS was associated with significant biomarker reductions within 5 days in confinement, these reductions being maintained throughout the ambulatory setting up to day 90. The results provide evidence that switching to mTHS reduces real-life exposure to HPHCs in adult smokers.

A six-month systems toxicology inhalation/cessation study in ApoE-/- mice to investigate cardiovascular and respiratory exposure effects of modified risk tobacco products, CHTP 1.2 and THS 2.2, compared with conventional cigarettes

Smoking is one of the major modifiable risk factors in the development and progression of chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD). Modified-risk tobacco products (MRTP) are being developed to provide substitute products for smokers who are unable or unwilling to quit, to lessen the smoking-related health risks. In this study, the ApoE-/- mouse model was used to investigate the impact of cigarette smoke (CS) from the reference cigarette 3R4F, or aerosol from two potential MRTPs based on the heat-not-burn principle, carbon heated tobacco product 1.2 (CHTP1.2) and tobacco heating system 2.2 (THS 2.2), on the cardiorespiratory system over a 6-month period. In addition, cessation or switching to CHTP1.2 after 3 months of CS exposure was assessed. A systems toxicology approach combining physiology, histology and molecular measurements was used to evaluate the impact of MRTP aerosols in comparison to CS. CHTP1.2 and THS2.2 aerosols, compared with CS, demonstrated lower impact on the cardiorespiratory system, including low to absent lung inflammation and emphysematous changes, and reduced atherosclerotic plaque formation. Molecular analyses confirmed the lower engagement of pathological mechanisms by MRTP aerosols than CS. Both cessation and switching to CHTP1.2 reduced the observed CS effects to almost sham exposure levels.

[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.

Vascular endothelial function is impaired by aerosol from a single IQOS HeatStick to the same extent as by cigarette smoke

BACKGROUND

Heated tobacco products (also called 'heat-not-burn' products) heat tobacco at temperatures below that of combustion, causing nicotine and other compounds to aerosolise. One such product, IQOS from Philip Morris International, is being marketed internationally with claims of harm reduction. We sought to determine whether exposure to IQOS aerosol impairs arterial flow-mediated dilation (FMD), a measure of vascular endothelial function that is impaired by tobacco smoke.

METHODS

We exposed anaesthetised rats (n=8/group) via nose cone to IQOS aerosol from single HeatSticks, mainstream smoke from single Marlboro Red cigarettes or clean air for a series of consecutive 30 s cycles over 1.5-5 min. Each cycle consisted of 15 or 5 s of exposure followed by removal from the nose cone. We measured pre-exposure and postexposure FMD, and postexposure serum nicotine and cotinine.

RESULTS

FMD was impaired comparably by ten 15 s exposures and ten 5 s exposures to IQOS aerosol and to cigarette smoke, but not by clean air. Serum nicotine levels were similar to plasma levels after humans have smoked one cigarette, confirming that exposure conditions had real-world relevance. Postexposure nicotine levels were ~4.5-fold higher in rats exposed to IQOS than to cigarettes, despite nicotine being measured in the IQOS aerosol at ~63% the amount measured in smoke. When IQOS exposure was briefer, leading to comparable serum nicotine levels to the cigarette group, FMD was still comparably impaired.

CONCLUSIONS

Acute exposures to IQOS aerosol impairs FMD in rats. IQOS use does not necessarily avoid the adverse cardiovascular effects of smoking cigarettes.

Quantifying the risk-reduction potential of new Modified Risk Tobacco Products

Quantitative risk assessment of novel Modified Risk Tobacco Products (MRTP) must rest on indirect measurements that are indicative of disease development prior to epidemiological data becoming available. For this purpose, a Population Health Impact Model (PHIM) has been developed to estimate the reduction in the number of deaths from smoking-related diseases following the introduction of an MRTP. One key parameter of the model, the F-factor, describes the effective dose upon switching from cigarette smoking to using an MRTP. Biomarker data, collected in clinical studies, can be analyzed to estimate the effects of switching to an MRTP as compared to quitting smoking. Based on transparent assumptions, a link function is formulated that translates these effects into the F-factor. The concepts of 'lack of sufficiency' and 'necessity' are introduced, allowing for a parametrization of a family of link functions. These can be uniformly sampled, thus providing different 'scenarios' on how biomarker-based evidence can be translated into the F-factor to inform the PHIM.

Acute eosinophilic pneumonia following heat-not-burn cigarette smoking

A 20‐year‐old man was admitted with acute respiratory failure. He had started smoking 20 heat‐not‐burn cigarettes (HC) per day 6 months previously, then purchased a second device for smoking HC to increase smoking to 40 cigarettes per day 2 weeks before hospitalization. Acute eosinophilic pneumonia (AEP) was diagnosed based on medical history, chest high‐resolution computed tomographic findings, and bronchoalveolar lavage fluid eosinophilia. On starting treatment with prednisolone, the patient exhibited complete recovery. A relationship between cigarette smoking and AEP has been suggested. HC were released in September 2015 in Japan, Italy, and Switzerland. HC attract attention as a cigarette generating less harmful substances than a conventional cigarette. We herein report the first case of AEP caused by smoking HC. HC are expected to spread around the world. In the same way as a conventional cigarette, HC should be recognized as a potential cause of AEP.

A systematic review of health effects of electronic cigarettes

OBJECTIVE

To provide a systematic review of the existing literature on health consequences of vaporing of electronic cigarettes (ECs).

METHODS

Search in: PubMed, EMBASE and CINAHL.

INCLUSION CRITERIA

Original publications describing a health-related topic, published before 14 August 2014. PRISMA recommendations were followed. We identified 1101 studies; 271 relevant after screening; 94 eligible.

RESULTS

We included 76 studies investigating content of fluid/vapor of ECs, reports on adverse events and human and animal experimental studies. Serious methodological problems were identified. In 34% of the articles the authors had a conflict of interest. Studies found fine/ultrafine particles, harmful metals, carcinogenic tobacco-specific nitrosamines, volatile organic compounds, carcinogenic carbonyls (some in high but most in low/trace concentrations), cytotoxicity and changed gene expression. Of special concern are compounds not found in conventional cigarettes, e.g. propylene glycol. Experimental studies found increased airway resistance after short-term exposure. Reports on short-term adverse events were often flawed by selection bias.

CONCLUSIONS

Due to many methodological problems, severe conflicts of interest, the relatively few and often small studies, the inconsistencies and contradictions in results, and the lack of long-term follow-up no firm conclusions can be drawn on the safety of ECs. However, they can hardly be considered harmless.

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 4: Eight-day randomized clinical trial in Korea

A randomized, controlled, open-label parallel-group, single-center study to determine biomarkers of exposure to 12 selected harmful and potentially harmful constituents (HPHC) in cigarette smoke and urinary excretion of mutagenic material in 72 male and female Korean subjects smoking Lark One cigarettes (1.0mg tar, 0.1mg nicotine, and 1.5mg CO) at baseline. Subjects were randomized to continue smoking Lark One cigarettes, or switch to an Electrically Heated Cigarette Smoking System (EHCSS) and EHCSS-K3 cigarette (3mg tar, 0.2mg nicotine, and 0.6 mg CO), or to no-smoking. The mean decreases from baseline to Day 8 were statistically significant (all p<0.05) for 10 of 12 HPHC in mainstream cigarette smoke including CO (the primary objective) in the EHCSS-K3 group (range: -1.5% to -74.2%). Exposure to the other determined HPHC was not significantly different. In the Lark One group, the mean exposure to 6 of 12 HPHC in cigarette smoke was significantly (all p<0.05) decreased; however, exposure to CO was significantly increased. The largest mean reductions in biomarkers of exposure to HPHC occurred in smokers who switched to no-smoking (-3.4% to -98.9%). The mean excretion of mutagenic material was significantly decreased (p<0.05) in the EHCSS-K3 and no-smoking groups (-31.8% and -45.3%, respectively), and increased in the Lark One group (+31.5%).

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 7: A one-month, randomized, ambulatory, controlled clinical study in Poland

This randomized, open-label, ambulatory, controlled clinical study investigated biomarkers associated with cardiovascular risk and biomarkers of exposure to 10 selected harmful and potentially harmful constituents (HPHC) in cigarette smoke in 316 male and female Polish smokers. Subjects were randomized to continue smoking conventional cigarettes (CC; N=79) or switch to smoking the Electrically Heated Cigarette Smoking System series-K cigarette (EHCSS-K6; N=237). Biomarker assessments were performed at several time points during the study at baseline and during the 1-month investigational period. The primary biomarkers were high-sensitivity C-reactive protein and white blood cell counts. No statistically significant differences in the two primary biomarkers were found between the study groups at the end of the study. End-of-study comparisons of secondary biomarkers between study groups indicated an increase in high-density lipoprotein cholesterol, and reductions in red blood cell count, hemoglobin, and hematocrit levels in the EHCSS-K6 group. All biomarkers of exposure to cigarette smoke HPHC were decreased in the EHCSS-K6 group, despite an increase in cigarette consumption, compared to the CC group. There were no apparent differences in any of the safety assessment parameters between the groups, and the overall incidence of study-related adverse events was low.

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 6: 6-Day randomized clinical trial of a menthol cigarette in Japan

A randomized, controlled, open-label, parallel-group, single-center study to determine biomarkers of exposure to 12 selected harmful and potentially harmful constituents (HPHC) in cigarette smoke, excretion of mutagenic material in urine, and serum Clara cell 16-kDa protein (CC16) in 102 male and female Japanese subjects who smoked Marlboro Ultra Lights Menthol cigarettes (M4J(M); 4 mg tar and 0.3mg nicotine) at baseline. Subjects were randomized to continue smoking M4J(M), or switch to smoking either the Electrically Heated Cigarette Smoking System menthol cigarette (EHCSS-K6(M); 5mg tar and 0.3mg nicotine) or the Lark One menthol cigarette (Lark1(M); 1mg tar and 0.1mg nicotine), or to no-smoking. The mean decreases from baseline to Day 5/6 were statistically significant (p ≤ 0.05) for exposure to 10 of 12 cigarette smoke HPHC including the primary endpoint (carbon monoxide) and urinary excretion of mutagenic material in the EHCSS-K6(M) group (-12.3% to -83.4%). Smaller, but statistically significant reductions (p ≤ 0.05) occurred in the Lark1(M) group (-3.3% to -35.2%), with the exception of urinary mutagens. The largest mean reductions (all p ≤ 0.05) in exposure to cigarette smoke HPHC and excretion of mutagenic material occurred in the no-smoking group (-1.4% to -93.6%). Serum CC16, an indicator of lung epithelial injury, was not significantly different between groups.

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 2: Smoke chemistry and in vitro toxicological evaluation using smoking regimens reflecting human puffing behavior

Chemical analysis of up to 49 harmful and potentially harmful constituents (HPHC) in mainstream smoke, in vitro cytotoxicity of the particulate and gas/vapor phase of mainstream smoke determined in the Neutral Red Uptake assay, and in vitro bacterial mutagenicity of the particulate phase determined in the Salmonella typhimurium Reverse Mutation (Ames) assay are reported for three Electrically Heated Cigarette Smoking System (EHCSS) series-K cigarettes, the University of Kentucky Reference Cigarette 2R4F, and a number of comparator commercial conventional lit-end cigarettes (CC) under ISO machine-smoking conditions and a total of 25 additional smoking regimens reflecting 'human puffing behavior' (HPB). The smoking machines were set to deliver nicotine yields for the EHCSS and comparator CC derived from the 10th percentile to the 90th percentile of nicotine uptake distributions in smokers determined in two clinical studies. Duplication of the smoking intensity 'per cigarette' on a smoking machine may provide an insight into product performance that is directly relevant to obtaining scientific evidence for reduced exposure substantiation based on mainstream cigarette smoke HPHC-to-nicotine regressions. The reported data support an overall evaluation of reduced exposure to HPHC and biological activity.

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 3: Eight-day randomized clinical trial in the UK

A randomized, controlled, open-label, parallel-group, single-center study to determine biomarkers of exposure to nine selected harmful and potentially harmful constituents (HPHC) in cigarette smoke and urinary excretion of mutagenic material in 160 male and female subjects smoking Marlboro cigarettes (6 mg tar, 0.5mg nicotine, and 7.0mg CO) at baseline. Subjects were randomized to continue smoking Marlboro cigarettes, or switch to using an Electrically Heated Cigarette Smoking System (EHCSS) smoking one of two EHCSS series-K cigarettes, the EHCSS-K6 cigarette (5mg tar, 0.3mg nicotine, and 0.6 mg CO) or the EHCSS-K3 cigarette (3mg tar, 0.2mg nicotine, and 0.6 mg CO), or switch to smoking Philip Morris One cigarettes (1mg tar, 0.1mg nicotine, and 2.0mg CO), or to no-smoking. The mean decreases from baseline to Day 8 were statistically significant (p ≤ 0.05) for all determined HPHC including benzene and CO (the primary objectives), and urinary excretion of mutagenic material in the EHCSS-K6 (range -35.5 ± 29.2% to -79.4 ± 14.6% [mean ± standard deviation]), EHCSS-K3 (range -41.2 ± 26.6% to -83.1 ± 9.2%), and PM1 (range -14.6 ± 24.1% to -39.4 ± 17.5%) groups. The largest reductions in exposure occurred in the no-smoking group (range -55.4 ± 45.0% to -100.0 ± 0.0%).

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 1: Non-clinical and clinical insights

The following series of papers presents an extensive assessment of the Electrically Heated Cigarette Smoking System EHCSS series-K cigarette vs. conventional lit-end cigarettes (CC) as an example for an extended testing strategy for evaluation of reduced exposure. The EHCSS produces smoke through electrical heating of tobacco. The EHCSS series-K heater was designed for exclusive use with EHCSS cigarettes, and cannot be used to smoke (CC). Compared to the University of Kentucky Reference Research cigarette 2R4F and a series of commercial CC, mainstream cigarette smoke of both the non-menthol and menthol-flavored EHCSS cigarettes showed a reduced delivery of a series of selected harmful and potentially harmful constituents (HPHC), mutagenic activity determined using the Salmonella typhimurium Reverse Mutation (Ames) assay, and cytotoxicity in the Neutral Red Uptake Assay. Clinical evaluations confirmed reduced exposure to HPHC and excretion of mutagenic material under controlled clinical conditions. Reductions in HPHC exposure were confirmed in a real-world ambulatory clinical study. Potential biomarkers of cardiovascular risk were also reduced under real-world ambulatory conditions. A modeling approach, 'nicotine bridging', was developed based on the determination of nicotine exposure in clinical evaluations which indicated that exposure to HPHC for which biomarkers of exposure do not exist would also be reduced.