Clinical trials methods for evaluation of potential reduced exposure products

Investigation of exposure biomarkers in human plasma following differing levels of tobacco-specific N-nitrosamines and nicotine in cigarette smoke

Tobacco-specific N-nitrosamines (TSNAs) are strong carcinogens widely found in tobacco products, environmental tobacco smoke, lake, and wastewater. The main objective of this study was to investigate the effects of cigarette smoke with different yields of TSNAs (NNK, NNN, NAT, NAB) and nicotine on the levels of biomarkers of exposure in smokers' plasma. Three hundred healthy volunteers were recruited comprising 60 smokers of each of 3 mg, 8 mg and 10 mg ISO tar yield cigarettes and 60 smokers who smoked 10 mg, 8 mg, and 3 mg for 14 days sequentially and 60 non-smokers. All study participants were male, aged from 21 to 45 years old, and were recruited from a same unit in Hebei, China. We measured the levels of NNAL, NAT, NNN, NAB and cotinine in plasma from 240 smokers and 60 non-smokers using a novel method established by online two-dimensional solid phase extraction-liquid chromatography-tandem mass spectrometry. The results showed that NNAL, NAT, NNN, NAB and cotinine in the plasma of smokers smoking cigarette with low TSNAs and nicotine were lower than that with high TSNAs and nicotine. When smokers switched from higher to lower TSNA yields of cigarettes, their plasma NNAL, NAT, NNN, NAB levels significantly decreased. The plasma concentrations of NNAL were significantly correlated with those of cotinine, NNN, NAT and NAB for smokers (p < 0.001). Similarly, the plasma concentrations of cotinine were significantly correlated with those of NNN, NAT and NAB for smokers (p < 0.001). The plasma NNAL, NAT, NNN, NAB and cotinine levels for smokers were significantly higher than those for non-smokers. These findings suggested that the total NNAL, NNN, NAT, NAB and cotinine in plasma were valid and reliable biomarkers for human exposure to TSNAs and nicotine.

Reductions in biomarkers of exposure to selected harmful and potentially harmful constituents following exclusive and partial switching from combustible cigarettes to myblu™ electronic nicotine delivery systems (ENDS)

Electronic nicotine delivery systems (ENDS) offer adult combustible cigarette smokers an alternative, potentially reduced harm, mode of nicotine delivery, attributed to fewer and reduced levels of harmful and potentially harmful constituents (HPHCs) in their aerosols compared to cigarette smoke. These two identical, randomised, open label, two-part studies aimed to compare levels of 15 biomarkers of exposure (BoE) to selected HPHCs associated with tobacco smoking in healthy US adult smoker subjects (n = 72). Following 9 days of exclusive use of a range of allocated myblu™ ENDS variants, subjects' levels of 14 non-nicotine BoE were substantially reduced compared to baseline values (combustible cigarette use), in the range of 46-97%. BoE reductions were sustained in subjects who continued myblu use exclusively (n = 25) for a further 5 days, and returned to near baseline levels in subjects who returned to exclusive combustible cigarette use (n = 21). Dual users (n = 24) demonstrated reductions in BoE to a lesser extent than with exclusive myblu use. Measured nicotine equivalents did not significantly change throughout the study. These data suggest exclusive use of ENDS provides adult smokers seeking an alternative to combustible cigarettes with substantial reductions in HPHC exposures whilst achieving satisfying levels of nicotine delivery. Dual use involving substitution of cigarettes may also provide some of this advantage, but to lesser extent. Overall, the data contribute to the weight of evidence that ENDS are an important tool in tobacco harm reduction for adult smokers unwilling to or uninterested in quitting smoking. Study 1: NCT04430634, study 2: NCT04429932, clinicaltrials.gov (10-06-2020).

A Randomized Clinical Trial of Snus Examining the Effect of Complete Versus Partial Cigarette Substitution on Smoking-Related Behaviors, and Biomarkers of Exposure

INTRODUCTION

This 8-week multisite, randomized controlled trial of snus examined the differential effects of instructions on (1) snus use, (2) smoking and smoking-related measures, and (3) exposure to tobacco-related constituents.

METHOD

US adult daily cigarette smokers (n = 150; 43.3% female; Medianage = 43.5) were recruited from Minneapolis, Minnesota; Columbus and Coshocton, Ohio; and Buffalo, New York. Following a 1-week sampling phase of snus, participants who used at least 7 pouches were randomized to either (1) partial substitution (PS; "use snus as you like with your cigarettes"), (2) complete substitution (CS; "avoid cigarettes"), or (3) usual brand cigarettes (UB). Analyses included between-group analyses (eg, PS vs. CS) using Wilcoxon rank sum test of cigarettes per day and snus pouches per day, and a linear mixed model (biomarkers).

RESULTS

Compared to the PS and UB groups, smokers assigned to CS reported greater reductions in cigarettes per day (ps < .001), using more snus pouches per day (p = .02), and more smoke-free days (CS median = 14.5, PS and UB medians = 0, p < .001). In addition, results demonstrated reductions in carbon monoxide (p < .001), total nicotine equivalents (p = .02), and four out of five measured volatile organic compounds (ps < .01) over time among the CS group. Exposure to N'-nitrosonornicotine increased by trial end only among the PS group (p < .04). Phenanthrene tetraol increased among all groups by trial end (p = .02) with no difference between groups.

CONCLUSIONS

Instructions to completely switch from cigarettes to snus resulted in the greatest reduction in cigarettes and exposure to harmful constituents.

IMPLICATIONS

Directly instructing smokers to switch completely to snus, rather than using ad libitum (with no instructions to avoid cigarettes), is necessary for reductions in smoking and subsequent exposure to harmful constituents.

Triangulating abuse liability assessment for flavoured cigar products using physiological, behavioural economic and subjective assessments: a within-subjects clinical laboratory protocol

INTRODUCTION

In the USA, Food and Drug Administration regulations prohibit the sale of flavoured cigarettes, with menthol being the exception. However, the manufacture, advertisement and sale of flavoured cigar products are permitted. Such flavourings influence positive perceptions of tobacco products and are linked to increased use. Flavourings may mask the taste of tobacco and enhance smoke inhalation, influencing toxicant exposure and abuse liability among novice tobacco users. Using clinical laboratory methods, this study investigates how flavour availability affects measures of abuse liability in young adult cigarette smokers. The specific aims are to evaluate the effect of cigar flavours on nicotine exposure, and behavioural and subjective measures of abuse liability.

METHODS AND ANALYSES

Participants (projected n=25) are healthy smokers of five or more cigarettes per day over the past 3 months, 18-25 years old, naive to cigar use (lifetime use of 50 or fewer cigar products and no more than 10 cigars smoked in the past 30 days) and without a desire to quit cigarette smoking in the next 30 days. Participants complete five laboratory sessions in a Latin square design with either their own brand cigarette or a session-specific Black & Mild cigar differing in flavour (apple, cream, original and wine). Participants are single-blinded to cigar flavours. Each session consists of two 10-puff smoking bouts (30 s interpuff interval) separated by 1 hour. Primary outcomes include saliva nicotine concentration, behavioural economic task performance and response to various questionnaire items assessing subjective effects predictive of abuse liability. Differences in outcomes across own brand cigarette and flavoured cigar conditions will be tested using linear mixed models.

ETHICS AND DISSEMINATION

The Virginia Commonwealth University Institutional Review Board approved the study (VCU IRB: HM20007848). Dissemination channels for study findings include scientific journals, scientific meetings, and policy briefs.

TRIAL REGISTRATION NUMBER

NCT02937051.

Consortium on Methods Evaluating Tobacco: Research Tools to Inform US Food and Drug Administration Regulation of Snus

Introduction

The US Food and Drug Administration (FDA) has purview over tobacco products. To set policy, the FDA must rely on sound science, yet most existing tobacco research methods have not been designed to specifically inform regulation. The NCI and FDA-funded Consortium on Methods Evaluating Tobacco (COMET) was established to develop and assess valid and reliable methods for tobacco product evaluation. The goal of this article is to describe these assessment methods using a US manufactured "snus" as the test product.

Methods

In designing studies that could inform FDA regulation, COMET has taken a multidisciplinary approach that includes experimental animal models and a range of human studies that examine tobacco product appeal, addictiveness, and toxicity. This article integrates COMET's findings over the last 4 years.

Results

Consistency in results was observed across the various studies, lending validity to our methods. Studies showed low abuse liability for snus and low levels of consumer demand. Toxicity was less than cigarettes on some biomarkers but higher than medicinal nicotine.

Conclusions

Using our study methods and the convergence of results, the snus that we tested as a potential modified risk tobacco product is likely to neither result in substantial public health harm nor benefit.

Implications

This review describes methods that were used to assess the appeal, abuse liability, and toxicity of snus. These methods included animal, behavioral economics, consumer perception studies, and clinical trials. Across these varied methods, study results showed low abuse-liability and appeal of the snus product we tested. In several studies, demand for snus was lower than for less toxic nicotine gum. The consistency and convergence of results across a range of multi-disciplinary studies lends validity to our methods and suggests that promotion of snus as a modified risk tobacco products is unlikely to produce substantial public health benefit or harm.

Cigarette Filter Ventilation and its Relationship to Increasing Rates of Lung Adenocarcinoma

The 2014 Surgeon General's Report on smoking and health concluded that changing cigarette designs have caused an increase in lung adenocarcinomas, implicating cigarette filter ventilation that lowers smoking machine tar yields. The Food and Drug Administration (FDA) now has the authority to regulate cigarette design if doing so would improve public health. To support a potential regulatory action, two weight-of-evidence reviews were applied for causally relating filter ventilation to lung adenocarcinoma. Published scientific literature (3284 citations) and internal tobacco company documents contributed to causation analysis evidence blocks and the identification of research gaps. Filter ventilation was adopted in the mid-1960s and was initially equated with making a cigarette safer. Since then, lung adenocarcinoma rates paradoxically increased relative to other lung cancer subtypes. Filter ventilation 1) alters tobacco combustion, increasing smoke toxicants; 2) allows for elasticity of use so that smokers inhale more smoke to maintain their nicotine intake; and 3) causes a false perception of lower health risk from "lighter" smoke. Seemingly not supportive of a causal relationship is that human exposure biomarker studies indicate no reduction in exposure, but these do not measure exposure in the lung or utilize known biomarkers of harm. Altered puffing and inhalation may make smoke available to lung cells prone to adenocarcinomas. The analysis strongly suggests that filter ventilation has contributed to the rise in lung adenocarcinomas among smokers. Thus, the FDA should consider regulating its use, up to and including a ban. Herein, we propose a research agenda to support such an effort.

Expanding clinical laboratory tobacco product evaluation methods to loose-leaf tobacco vaporizers

BACKGROUND

Novel tobacco products entering the US market include electronic cigarettes (ECIGs) and products advertised to "heat, not burn" tobacco. There is a growing literature regarding the acute effects of ECIGs. Less is known about "heat, not burn" products. This study's purpose was to expand existing clinical laboratory methods to examine, in cigarette smokers, the acute effects of a "heat, not burn" "loose-leaf tobacco vaporizer" (LLTV).

METHODS

Plasma nicotine and breath carbon monoxide (CO) concentration and tobacco abstinence symptom severity were measured before and after two 10-puff (30-s interpuff interval) product use bouts separated by 60min. LLTV effects were compared to participants' own brand (OB) cigarettes and an ECIG (3.3V; 1.5ohm; 18mg/ml nicotine).

RESULTS

Relative to OB, LLTV increased plasma nicotine concentration to a lesser degree, did not increase CO, and did not appear to reduce abstinence symptoms as effectively. Relative to ECIG, LLTV nicotine and CO delivery and abstinence symptom suppression did not differ. Participants reported that both the LLTV and ECIG were significantly less satisfying than OB.

CONCLUSIONS

Results demonstrate that LLTVs are capable of delivering nicotine and suppressing tobacco abstinence symptoms partially; acute effects of these products can be evaluated using existing clinical laboratory methods. Results can inform tobacco product regulation and may be predictive of the extent that these products have the potential to benefit or harm overall public health.

Biomarkers of Tobacco Exposure: Summary of an FDA-Sponsored Public Workshop

Since 2009, the FDA Center for Tobacco Products (CTP) has had the authority to regulate the manufacturing, distribution, and marketing of tobacco products in order to reduce the death and disease caused by tobacco use. Biomarkers of exposure pertain to actual human exposure to chemicals arising from tobacco use and could play an important role across a number of FDA regulatory activities, including assessing new and modified-risk tobacco products and identifying and evaluating potential product standards. On August 3-4, 2015, FDA/CTP hosted a public workshop focused on biomarkers of exposure with participants from government, industry, academia, and other organizations. The workshop was divided into four sessions focused on: (i) approaches to evaluating and selecting biomarkers; (ii) biomarkers of exposure and relationship to disease risk; (iii) currently used biomarkers of exposure and biomarkers in development; and (iv) biomarkers of exposure and the assessment of smokeless tobacco and electronic nicotine delivery systems. This article synthesizes the main findings from the workshop and highlights research areas that could further strengthen the science around biomarkers of exposure and help determine their application in tobacco product regulation. Cancer Epidemiol Biomarkers Prev; 26(3); 291-302. ©2016 AACR.

Behavioral Economic Laboratory Research in Tobacco Regulatory Science

OBJECTIVES

Research that can provide a scientific foundation for the United States Food and Drug Administration (FDA) tobacco policy decisions is needed to inform tobacco regulatory policy. One factor that affects the impact of a tobacco product on public health is its intensity of use, which is determined, in part, by its abuse liability or reinforcing efficacy. Behavioral economic tasks have considerable utility for assessing the reinforcing efficacy of current and emerging tobacco products.

METHODS

This paper provides a narrative review of several behavioral economic laboratory tasks and identifies important applications to tobacco regulatory science.

RESULTS

Behavioral economic laboratory assessments, including operant self-administration, choice tasks and purchase tasks, can be used generate behavioral economic data on the effect of price and other constraints on tobacco product consumption. These tasks could provide an expedited simulation of the effects of various tobacco control policies across populations of interest to the FDA.

CONCLUSIONS

Tobacco regulatory research questions that can be addressed with behavioral economic tasks include assessments of the impact of product characteristics on product demand, assessments of the abuse liability of novel and potential modified risk tobacco products (MRTPs), and assessments of the impact of conventional and novel products in vulnerable populations.

Reference change values in concentrations of urinary and salivary biomarkers of exposure and mouth level exposure in individuals participating in an ambulatory smoking study

Background

Modified-risk tobacco products (MRTPs) are being developed that may contribute to tobacco harm reduction. To support reduced exposure or risk claims, a scientific framework needs to be developed to assess the validity of claims and monitor consumers after product launch. We calculated reference change values (RCVs) for biomarker of exposure (BoE): salivary cotinine and hydroxycotinine; and urinary total nicotine equivalents, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and creatinine. Mouth-level exposure (MLE) to nicotine and tar were also recorded in an ambulatory setting to characterise variation among smokers in their everyday environment.

Methods

This non-residential, observational study was conducted over 3.5 years across 10 sites in Germany. Smokers of the same commercial 10 mg ISO tar product were included in the study (N=1011). Urine samples, questionnaires and cigarette filters were collected every 6 months for a total of seven timepoints.

Results

Greater variability in BoEs was observed compared with confined clinical studies. Gaussian distributed data showed 2-sided values over 100%, which are uninformative for decreases. The proportion of significant changes increased slightly among switchers, probably as a result of additional variability due to the range of products used post-switching. Overall proportions of changes remained small, consistent with literature reporting that when switching to a different tar yield cigarette, smokers partially compensate by changing their smoking behaviour.

Conclusion

Variability estimates and RCVs can be useful for monitoring subjects' BoE and MLE endpoints in longitudinal smoking studies where subjects are followed in their own environment and to aid sample size calculation of studies involving these endpoints.

Preliminary Evaluation of a New German Translated Tobacco Quality of Life Impact Tool to Discriminate Between Healthy Current and Former Smokers and to Explore the Effect of Switching Smokers to a Reduced Toxicant Prototype Cigarette

BACKGROUND

Assessment of health-related quality of life (HRQoL) is well established in clinical research, but ceiling effects in validated tools might prevent detection of changes in well respondents. Tobacco Quality of Life Impact Tool (TQOLITv1) uses conceptual and psychometric advances to enhance detection of HRQoL changes.

METHODS

In a 6-month, forced-switch study, the German TQOLITv1 was assessed in healthy adult (age 23-55 years) current and matched former-smokers. At baseline, smokers were switched to reduced toxicant prototype (RTP) or conventional cigarette for 6 months. TQOLITv1 responses were collected at baseline, 3 and 6 months from current smokers whilst former smokers completed it at the latter two time points. TQOLITv1 includes SF-36v2 and new smoking-specific, physical and general-health measures.

RESULTS

Reliability at baseline was good (Cronbach's coefficient alpha > 0.70) for all measures. The baseline percentage with the best possible score (ceiling effect) for former and current smokers was substantially better for the new physical function than SF-36 physical function measure (35% vs. 59% at ceiling, respectively). New smoking-specific measures discriminated current from former smokers better than general health measures. Smoking-specific symptoms (r = 0.73) were more stable from baseline to 6 months than other measures (r = 0.38-0.54) particularly more than the SF-36 mental component score (r = 0.24). Although both product smoking groups worsened in most HRQoL measures, changes in general and smoking-specific HRQoL impact measures favored RTP smokers.

CONCLUSIONS

The German TQOLITv1 is sufficiently reliable and valid to assess HRQoL and may be more useful than SF-36v2 in evaluation of interventions in well smoking populations including those consuming RTPs.

Evaluation of smoking-specific and generic quality of life measures in current and former smokers in Germany and the United States

BACKGROUND

Health-related quality of life (QOL) surveys include generic measures that enable comparisons across conditions and measures that focus more specifically on one disease or condition. We evaluated the psychometric properties of German- and English-language versions of survey scales representing both types of measures in samples of current and former smokers.

METHODS

TQOLIT(™)v1 integrates new measures of smoking-specific symptoms and QOL impact attributed to smoking with generic SF-36 Health Survey measures. For purposes of evaluation, cross-sectional data were analyzed for two independent samples. Disease-free (otherwise healthy) adults ages 23-55 used a tablet to complete surveys in a clinical trial in Germany (125 current and 54 former smokers). Online general population surveys were completed in the US by otherwise healthy current and former smokers (N = 149 and 110, respectively). Evaluations included psychometric tests of assumptions underlying scale construction and scoring, score distributions, and reliability. Tests of validity included cross-sectional correlations and analyses of variance based on a conceptual framework and hypotheses for groups differing in self-reported smoking behavior (current versus former smoker, cigarettes per day (CPD)) and severity of smoking symptoms in both samples and, in the German trial only, clinical parameters of biomarkers of exposure.

RESULTS

Tests of scaling assumptions and internal consistency reliability (alpha = 0.71-0.79) of the smoking-specific measures were satisfactory, although ceiling effects attenuated correlations for former smokers in both samples. Correlational evidence supporting validity of smoking-specific symptom and impact measures included their substantial inter-correlation and higher correlations (than generic measures) with smoking behavior (favoring former over current groups) and CPD in both samples. In the German trial, both smoking-specific measures correlated significantly (p < 0.05) with all four biomarkers. QOL impact attributed to smoking correlated with the SF-36 mental but not physical summary measures in both samples.

CONCLUSIONS

German- and English-language TQOLITv1 surveys have comparable and satisfactory psychometric properties. Cross-sectional tests, including correlations with four biomarkers, support the validity of the new smoking-specific measures for use in studies of otherwise healthy smokers. Smoking-specific measures consistently performed better than generic QOL measures in all tests of validity.

Providing a Science Base for the Evaluation of Tobacco Products

OBJECTIVE

Evidence-based tobacco regulation requires a comprehensive scientific framework to guide the evaluation of new tobacco products and health-related claims made by product manufacturers.

METHODS

The Tobacco Product Assessment Consortium (TobPRAC) employed an iterative process involving consortia investigators, consultants, a workshop of independent scientists and public health experts, and written reviews in order to develop a conceptual framework for evaluating tobacco products.

RESULTS

The consortium developed a four-phased framework for the scientific evaluation of tobacco products. The four phases addressed by the framework are: (1) pre-market evaluation, (2) pre-claims evaluation, (3) post-market activities, and (4) monitoring and re-evaluation. For each phase, the framework proposes the use of validated testing procedures that will evaluate potential harms at both the individual and population level.

CONCLUSIONS

While the validation of methods for evaluating tobacco products is an ongoing and necessary process, the proposed framework need not wait for fully validated methods to be used in guiding tobacco product regulation today.

Magnitudes of biomarker reductions in response to controlled reductions in cigarettes smoked per day: a one-week clinical confinement study

Tobacco toxicant-related exposure reduction is an important tool in harm reduction. Cigarette per day reduction (CPDR) occurs as smokers migrate from smoking cigarettes to using alternative tobacco/nicotine products, or quit smoking. Few reports characterize the dose-response relationships between CPDR and effects on exposure biomarkers, especially at the low end of CPD exposure (e.g., 5 CPD). We present data on CPDR by characterizing magnitudes of biomarker reductions. We present data from a well-controlled, one-week clinical confinement study in healthy smokers who were switched from smoking 19-25 CPD to smoking 20, 10, 5 or 0 CPD. Biomarkers were measured in blood, plasma, urine, and breath, and included smoke-related toxicants, urine mutagenicity, smoked cigarette filter analyses (mouth level exposure), and vital signs. Many of the biomarkers (e.g., plasma nicotine) showed strong CPDR dose-response reductions, while others (e.g., plasma thiocyanate) showed weaker dose-response reductions. Factors that lead to lower biomarker reductions include non-CPD related contributors to the measured response (e.g., other exposure sources from environment, life style, occupation; inter-individual variability). This study confirms CPDR dose-responsive biomarkers and suggests that a one-week design is appropriate for characterizing exposure reductions when smokers switch from cigarettes to new tobacco products.

Reference change values to assess changes in concentrations of biomarkers of exposure in individuals participating in a cigarette-switching study

Background: In a previous clinical study, levels of biomarkers of exposure (BoEs) for specific toxicants were significantly reduced in smokers who switched from conventional cigarettes to reduced toxicant prototype (RTP) cigarettes. Very little is known about the biological variability of tobacco smoke BoEs within individuals and sub-groups, and the descriptive group-comparison statistics might not be sufficient to understand such changes. Therefore, we assessed how different statistical methods could be used to interpret changes in urine BoE levels at the individual level.

Methods: We used non-parametric statistical reference limits, the empirical rule and reference change values (RCVs) to assess changes in levels of BoEs related to four toxicants in cigarettes smoke. Current smokers [of 6 mg and 1 mg International Organization for Standardization (ISO) tar yields] were allocated to switching to RTP groups or non-switching control groups within their respective tar bands. There were two 6 mg tar study groups, with a non-switching group (CC6, n=46) and a group switching to an RTP containing tobacco-substitute sheet and modified filter (TSS6, n=49); and three 1 mg tar smoker groups, with one non-switching (CC1, n=42), a group switching to an RTP containing tobacco-substitute sheet and modified filter (TSS1, n=44) and one switching to an RTP containing an enzyme-treated tobacco and modified filter (BT1, n=47).

Results: Assessment of the direction of change showed that up to the 100% of subjects experienced a decrease in levels of some BoEs. Between 49% and 64% of subjects in the switching groups were classified as having decreased levels of 3-hydroxy-1-methylpropylmercapturic acid (HMPMA) by the non-parametric criterion, whereas only 2%–6% had reduced levels of N-nitrosoanatabine (NAT). Of non-switchers, in 7%–14% of those smoking 1 mg ISO tar yield cigarettes increases were classified across all BoEs. RCVs highlighted patterns with more detail, showing that most changes occurred within 14 days of switching. Among smokers who switched to 6 mg RTPs, 40%, 44%, 6% and 15%, respectively, were classified as experiencing significant decreasing levels of HPMA, 3-hydroxypropylmercapturic acid, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and NAT, whereas in the two 1 mg switching groups 46%, 22%, 11% and 52% and 43%, 27%, 2% and 16% had decreased levels of the same biomarkers. Up to five subjects in the 6 mg non-switching group were classified as having increased levels of all BoEs.

Conclusions: Although we believe that is not possible to determine whether the observed changes in BoEs reflect biological relevance, the use of reference values enables assessment of changes in BoEs at the individual level. Estimates of the BoE variability between subjects might aid study design and setting minimum targets for smoke toxicant yields for future development of RTPs.

A single-blinded, single-centre, controlled study in healthy adult smokers to identify the effects of a reduced toxicant prototype cigarette on biomarkers of exposure and of biological effect versus commercial cigarettes

BACKGROUND

Despite universal acceptance that smoking is harmful, a substantial number of adults continue to smoke. The development of potential reduced exposure products (more recently termed modified risk tobacco products) has been suggested as a way to reduce the risks of tobacco smoking. This trial is designed to investigate whether changes in toxicant exposure after switching from a commercial to reduced toxicant prototype (RTP) cigarette (7 mg International Organisation for Standardisation (ISO) tar yield) can be assessed by measurement of biomarkers and other factors. The primary objective is to descriptively assess changes in selected biomarkers of exposure (BoE) and biomarkers of biological effect (BoBE) within participants and within and between groups after switching. Secondary objectives are to assess similarly changes in other biomarkers, quality of life, smoking behaviours, physiological measures, mouth-level exposure to toxicants and sensory perception.

METHODS/DESIGN

This trial will assess current smokers, ex-smokers and never-smokers in a single-centre single-blind, controlled clinical trial with a forced-switching design and in-clinic (residential) and ambulatory (non-residential) periods. Smokers will be aged 23-55 years (minimum legal smoking age plus 5 years) and non-smokers 28-55 years (minimum legal smoking age plus 5 years, plus minimum 5 years since last smoked). Smokers will be allowed to smoke freely at all times. We will assess changes in selected BoE and BoBE and effective dose in urine and blood after switching. Creatinine concentrations in serum, creatinine clearance in urine, cotinine concentration in saliva, diaries and collection of spent cigarette filters will be used to assess compliance with the study protocol. Mouth-level exposure to toxins will be assessed by filter analysis.

DISCUSSION

Data from this study are expected to improve scientific understanding of the effects of RTP cigarettes on BoE and BoBE, and give insights into study design for clinical assessment of potential MRTPs.

TRIAL REGISTRATION

The study was registered in the Current Controlled Trials database under the reference ISRCTN81286286.

Postmarketing surveillance for "modified-risk" tobacco products

INTRODUCTION

The U.S. Food and Drug Administration (FDA) acquired authority to regulate tobacco products in 2009. This authority will provide a structured process for manufacturers to introduce products that may have "modified-risk" for morbidity or mortality relative to traditional tobacco products, with postmarketing surveillance and studies a condition of marketing.

METHOD

A narrative review approach was taken. The author searched and integrated publicly accessible literature on tobacco product surveillance as well as drug and medical device postmarket activities currently performed by FDA.

RESULTS

FDA relies on active and passive methods for postmarket surveillance and can require specific studies and risk evaluation and mitigation strategies for certain products, including those with abuse liability. Past efforts at examining the individual and population effects of reduced harm tobacco products provide an example of integrating different data streams.

DISCUSSION

Postmarket surveillance can be viewed in terms of the Agent-Host-Vector-Environment model, and concepts from diffusion of innovations are relevant to understanding factors associated with the adoption of new products by the population. Given that active and passive surveillance approaches have different strengths and weaknesses, multiple approaches may be necessary to evaluate population-level effects. Assuring that required studies are properly conducted and reported and that data indicating significant public health harms are quickly recognized will be important going forward.

CONCLUSIONS

The advent of broad regulatory authority over tobacco provides opportunities for policy evaluation research. The research community can provide FDA with the independent science it needs to evaluate the public health impact of novel tobacco products.

Tobacco and nicotine product testing

INTRODUCTION

Tobacco product testing is a critical component of the Family Smoking Prevention and Tobacco Control Act (FSPTCA), which grants the Food and Drug Administration the authority to regulate tobacco products. The availability of methods and measures that can provide accurate data on the relative health risks across types of tobacco products, brands, and subbrands of tobacco products on the validity of any health claims associated with a product, and on how consumers perceive information on products toxicity or risks is crucial for making decisions on the product's potential impact on public health. These tools are also necessary for making assessments of the impact of new indications for medicinal products (other than cessation) but more importantly of tobacco products that may in the future be marketed as cessation tools.

OBJECTIVE

To identify research opportunities to develop empirically based and comprehensive methods and measures for testing tobacco and other nicotine-containing products so that the best science is available when decisions are made about products or policies.

METHODS

Literature was reviewed to address sections of the FSPTCA relevant to tobacco product evaluation; research questions were generated and then reviewed by a committee of research experts.

RESULTS

A research agenda was developed for tobacco product evaluation in the general areas of toxicity and health risks, abuse liability, consumer perception, and population effects.

CONCLUSION

A cohesive, systematic, and comprehensive assessment of tobacco products is important and will require building consensus and addressing some crucial research questions.

Research opportunities related to establishing standards for tobacco products under the Family Smoking Prevention and Tobacco Control Act

INTRODUCTION

This paper was written in response to a request from the U.S. National Cancer Institute. The goal is to discuss some research directions related to establishing tobacco product standards under the Family Smoking Prevention and Tobacco Control Act, which empowers the U.S. Food and Drug Administration to regulate tobacco products. Potential research related to tobacco product ingredients, nicotine, and harmful or potentially harmful constituents of tobacco products is discussed.

DISCUSSION

Ingredients, which are additives, require less attention than nicotine and harmful or potentially harmful constituents. With respect to nicotine, the threshold level in tobacco products below which dependent users will be able to freely stop using the product if they choose to do so is a very important question. Harmful and potentially harmful constituents include various toxicants and carcinogens. An updated list of 72 carcinogens in cigarette smoke is presented. A crucial question is the appropriate levels of toxicants and carcinogens in tobacco products. The use of carcinogen and toxicant biomarkers to determine these levels is discussed.

CONCLUSIONS

The need to establish regulatory standards for added ingredients, nicotine, and other tobacco and tobacco smoke constituents leads to many interesting and potentially highly significant research questions, which urgently need to be addressed.

Estimation and correlation of cigarette smoke exposure in Canadian smokers as determined by filter analysis and biomarkers of exposure

A clinical study conducted in Canada compared two methods of estimating exposure to cigarette smoke in 192 volunteer subjects: 43 smokers of 4-6 mg, 49 of 8-12 mg and 50 of 14-15 mg ISO tar yield cigarettes and 50 non-smokers. Estimates of mouth level exposure (MLE) to nicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), pyrene and acrolein were obtained by chemical analysis of spent cigarette filters. Estimates of smoke constituent uptake were achieved by analysis of urinary biomarkers for total nicotine equivalents (nicotine, cotinine, trans-3'-hydroxycotinine plus their glucuronide conjugates), NNK (total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) plus glucuronide), pyrene (1-hydroxy pyrene plus glucuronide) and acrolein (3-hydroxylpropyl-mercapturic acid) plus the nicotine metabolite cotinine in plasma and saliva. The objective of our study was to confirm the correlations between measures of human exposure obtained by filter analysis and biomarkers. Significant correlations (p<0.001) were found between MLE and the relevant biomarker for each smoke constituent. The adjusted values of the Pearson correlation coefficients (r) were 0.80 (nicotine), 0.77 (acrolein) and 0.44 (pyrene). NNK correlations could not be obtained because of the low NNK yield of Canadian cigarettes. Unexpectedly high levels of acrolein biomarker found in non-smokers urine on one of the two days sampled emphasised the need for more than one sampling occasion per period and an awareness of non-tobacco sources of smoke constituents under investigation. No consistent dose response, in line with ISO tar yield smoked, of MLE estimates was found for nicotine, pyrene and acrolein and respective biomarkers. The influence of demographics on our results has also been examined.

Oral tobacco products: preference and effects among smokers

BACKGROUND

Recently, oral tobacco products have been marketed specifically towards cigarette smokers. These products come in different nicotine doses and formulations (snus vs. lozenge). To date, little research has been conducted to determine how smokers respond to these products. The goal of this study was to examine if smokers prefer certain oral tobacco products based on their specific characteristics.

METHODS

Smokers interested in quitting underwent a sampling phase and a treatment phase. The sampling phase consisted of testing five different products varying in nicotine dose (high vs. moderate vs. low) and formulation (snus vs. lozenge): General Snus, Camel Snus, Marlboro Snus, Stonewall and Ariva. Each product was sampled in the natural environment on separate days. At the end of the sampling period, subjects chose which product they would use during the 2-week cigarette abstinence phase.

RESULTS

General Snus (high nicotine) was not preferred by any smoker. No significant differences in preferences were observed across the other tobacco products. During the smoking cessation phase, Camel Snus was generally associated with greater craving relief and satisfaction, reduced use of cigarettes, and greater abstinence during follow-up compared to other products.

CONCLUSION

There were no differences in preferences for four of the five oral tobacco products but higher nicotine oral tobacco products were associated with better cessation outcomes among smokers who chose these products.

The use of a novel tobacco-substitute sheet and smoke dilution to reduce toxicant yields in cigarette smoke

The Institute of Medicine encouraged the pursuit and development of potential reduced-exposure products, tobacco products that substantially reduce exposure to one or more tobacco toxicants and can reasonably be expected to reduce the risk of one or more specific diseases or other adverse health effects. One approach to reducing smoke toxicant yields is to dilute the smoke with glycerol. We report chemical, biological and human exposure data related to experimental cigarettes containing up to 60% of a novel glycerol containing "tobacco-substitute" sheet. Analysis of mainstream smoke from experimental cigarettes showed reductions in yields of most measured constituents, other than some volatile species. In vitro toxicological tests showed reductions in the activity of smoke particulates in proportion to their glycerol content. Human exposure to nicotine was reduced by a mean of 18% as determined by filter studies and by 14% using 24h urinary biomarker analysis. Smoke particulate exposures were reduced by a mean of 29% in filter studies and NNK exposure by similar amounts based on urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol concentrations. These results show that reducing exposure to some smoke toxicants is possible using a tobacco-substitute sheet, although some smoke toxicants, and the sensory attributes of the smoke, remain as technical challenges.

Tobacco harm reduction and the evolution of nicotine dependence

In recent years, a renewed debate has developed around the potential for modified tobacco products to play a role in reducing tobacco-related harm. During the 1960s and 1970s medical experts recommended to smokers who could not quit that they switch to cigarettes with lower tar and nicotine content. At the time, survey data suggested that smokers who switched did not compensate for the reduction in nicotine by increasing their intake. However, public health scientists were hindered in their ability to evaluate the population impact of the reduced tar strategy by a limited understanding of nicotine addiction. Smoking dependence was seen as primarily psychological and social, rather than pharmacological or biological, until the late 1970s, when addiction researchers began to apply experimental techniques from other forms of drug abuse to study smoking behavior. This history has important lessons for current discussions about tobacco harm reduction and regulation of nicotine delivery.

Electronic nicotine delivery systems: a research agenda

Electronic nicotine delivery systems (ENDS, also called electronic cigarettes or e-cigarettes) are marketed to deliver nicotine and sometimes other substances by inhalation. Some tobacco smokers report that they used ENDS as a smoking cessation aid. Whether sold as tobacco products or drug delivery devices, these products need to be regulated, and thus far, across countries and states, there has been a wide range of regulatory responses ranging from no regulation to complete bans. The empirical basis for these regulatory decisions is uncertain, and more research on ENDS must be conducted in order to ensure that the decisions of regulators, health care providers and consumers are based on science. However, there is a dearth of scientific research on these products, including safety, abuse liability and efficacy for smoking cessation. The authors, who cover a broad range of scientific expertise, from basic science to public health, suggest research priorities for non-clinical, clinical and public health studies. They conclude that the first priority is to characterize the safety profile of these products, including in long-term users. If these products are demonstrated to be safe, their efficacy as smoking cessation aids should then be tested in appropriately designed trials. Until these studies are conducted, continued marketing constitutes an uncontrolled experiment and the primary outcome measure, poorly assessed, is user health. Potentially, this research effort, contributing to the safety and efficacy of new smoking cessation devices and to the withdrawal of dangerous products, could save many lives.

Does switching to reduced ignition propensity cigarettes alter smoking behavior or exposure to tobacco smoke constituents?

INTRODUCTION

Since 2004, several jurisdictions have mandated that cigarettes show reduced ignition propensity (RIP) in laboratory testing. RIP cigarettes may limit fires caused by smoldering cigarettes, reducing fire-related deaths and injury. However, some evidence suggests that RIP cigarettes emit more carbon monoxide and polycyclic aromatic hydrocarbons, and smokers may alter their smoking patterns in response to RIP cigarettes. Both of these could increase smokers' exposures to harmful constituents in cigarettes.

METHODS

An 18-day switching study with a comparison group was conducted in Boston, MA (N = 77), and Buffalo, NY (N = 83), in 2006-2007. Current daily smokers completed 4 laboratory visits and two 48-hr field data collections. After a 4-day baseline, Boston participants switched to RIP cigarettes for 14 days, whereas Buffalo participants smoked RIP cigarettes throughout. Outcome measures included cigarettes smoked per day; smoking topography; salivary cotinine; breath CO; and hydroxylated metabolites of pyrene, naphthalene, phenanthrene, and fluorene. Because the groups differed demographically, analyses adjusted for race, age, and sex.

RESULTS

We observed no significant changes in smoking topography or CO exposure among participants who switched to RIP cigarettes. Cigarette use decreased significantly in the switched group (37.7 cigarettes/48 hr vs. 32.6 cigarettes/48 hr, p = .031), while hydroxyphenanthrenes increased significantly (555 ng/g creatinine vs. 669 ng/g creatinine, p = .007). No other biomarkers were significantly affected.

DISCUSSION

Small increases in exposure to phenanthrene among smokers who switched to RIP versions were observed, while other exposures and smoking topography were not significantly affected. Toxicological implications of these findings are unclear. These findings should be weighed against the potential public health benefits of adopting RIP design standards for cigarette products.

Applying tobacco carcinogen and toxicant biomarkers in product regulation and cancer prevention

Tobacco carcinogen and toxicant biomarkers are metabolites or protein or DNA adducts of specific compounds in tobacco products. Highly reliable analytical methods, based mainly on mass spectrometry, have been developed and applied in large studies of many of these biomarkers. A panel of tobacco carcinogen and toxicant biomarkers is suggested here, and typical values for smokers and nonsmokers are summarized. This panel of biomarkers has potential applications in the new and challenging area of tobacco product regulation and in the development of rational approaches to cancer prevention by establishing carcinogen and toxicant uptake and excretion in people exposed to tobacco products.

Methods used in internal industry clinical trials to assess tobacco risk reduction

OBJECTIVE

Methods to assess reduced exposure products should include those that aid in determining likely patterns of human use and exposure. Tobacco industry clinical trial methods may provide insight into strategies to assess potential reduced exposure products (PREP) for public health purposes. Internal tobacco industry documents detailing human clinical research with PREPs were examined to document major research strategies used and identify potentially fruitful methods not currently used in the mainstream arena.

METHODS

Primary data were obtained from records of research conducted internally by tobacco companies and affiliated researchers, and included manuscript drafts, presentations, protocols, and instruments relating to internal clinical trials of human tobacco use and exposure.

RESULTS

Tobacco industry clinical research has focused on reduced exposure products, most notably Premier, Accord, and Eclipse. The most widely used strategy observed is switching studies, and details of study designs and protocols favored by the industry are described. Key measures include biomarkers of exposure (e.g., cotinine, CO, and specific carcinogens) and acute health effects such as physical health and fitness.

CONCLUSIONS

Tobacco industry clinical research has used relatively standard switching study methods, but with a broad set of measures. Clinical switching studies have been conducted by the industry primarily to support existing claims or to develop new claims. Knowledge of prior industry activity can guide and inform future public health research efforts. Although industry clinical trial methods are comparable with current mainstream methods, limited information about the validity of outcome measures used limits their viability for immediate adoption in mainstream science.

Abuse liability assessment of tobacco products including potential reduced exposure products

The harm produced by tobacco products is a result of frequent use of a highly toxic product. Reducing the adverse public health impact of tobacco products might be most effectively achieved by reducing the likelihood of their use and the toxicity of the products. Products that retain some characteristics of cigarettes but have been altered with the intention of reducing toxicity have been referred to as modified risk tobacco products or potential reduced exposure products (MRTP/PREP). Evaluation of their content, emission, and toxicity is discussed in other articles in this special issue. Here, we discuss the methodology that has been used to examine the likelihood of abuse or addiction. Abuse liability assessment (ALA) methodology has been used by the Food and Drug Administration (FDA) and other drug regulatory agencies world-wide for decades to assess the risks posed by a wide variety of pharmacologically active substances. ALA is routinely required among other evaluations of safety during the pre-market assessment of new drugs, and is continually adapted to meet the challenges posed by new drug classes and drug formulations. In the 2009 law giving FDA regulation over tobacco products, FDA is now required to evaluate new tobacco products including MRTP/PREPs to determine their risk for abuse and toxicity at the population level. This article describes the traditional tools and methods of ALA that can be used to evaluate new tobacco and nicotine products including MRTP/PREPs. Such ALA data could contribute to the scientific foundation on which future public policy decisions are based.

Measures for assessing subjective effects of potential reduced-exposure products

Potential reduced-exposure products (PREP) may reduce toxicant exposure and thereby may possibly reduce health risks associated with conventional tobacco use. However, lessened health risk to the individual or harm to the population through the use of PREPs is unknown. Research is being conducted to evaluate the possible health effects associated with PREP use. As part of this evaluation, it is critical to provide sound measures of subjective responses to PREPs to determine the use and the abuse potential of a product, that is, the likelihood that the product will lead to addiction. The goal of this paper is to conduct a systematic review of scales that have been used to measure the subjective responses to PREPs and examine their characteristics. In this article, scales are identified and the items on the scales are described. Scales are also examined to determine whether they are sensitive in testing PREPs. Furthermore, scales to assess PREPs are recommended to investigators. Where no scales exist, items that may be critical for the development and validation of new scales are identified.