COMET Study 1: Filter Ventilated Cigarette Substitution in the ETM

Virginia Polytechnic Institute and State University logo

Virginia Polytechnic Institute and State University




Substance-Related Disorders


Other: Commercially available cigarette

Study type


Funder types



CigVent Proj-003
1P01CA217806 (U.S. NIH Grant/Contract)

Details and patient eligibility


Early attempts by the tobacco industry to develop "safer" cigarettes led to the widespread introduction of ventilation holes in cigarette filters; however, this design feature may instead increase smoking-related harm and make cigarettes more palatable. The overall goal of this project is to model regulatory restrictions banning cigarette filter ventilation and determine their effects on consumption of both cigarettes and a wide range of alternative tobacco products. Testing potential regulatory actions under controlled conditions will facilitate evidence-based policies that have a net benefit to health.

Full description

The duration of the experiment will be approximately 3 months. Participants will begin with an initial one week (approximately) exposure period to both unventilated and ventilated cigarettes as well as alternative nicotine products (e-cigarettes, snus, etc.) that will be made available throughout the experiment. Participants will be given the opportunity to sample both types of cigarettes and alternative nicotine products. In the following sessions, participants will alternate between Electronic Tobacco Marketplace (ETM) sessions and free exposure periods to their assigned cigarette, with weekly assessments throughout to track changes in smoking behavior and cigarette valuation. In total, participants will complete 10 experimental sessions (see Appendix B for experimental timeline figure). For the sake of clarity, session types are separated below. The consent and initial sessions may take place in the same or separate sessions. At the beginning of the experiment, participants will be assigned to one of two groups: ventilated or unventilated. Group assignment will determine what cigarettes will be given to the participant after sessions in which they do not actually purchase their cigarettes of choice. Additionally, participants that typically smoke menthol cigarettes will be given a menthol version of their assigned cigarette. Cigarettes will be similar in design and will be labeled as Typa A or Type B. At the initial session and throughout the study, urine samples may be collected and stored for testing (for tobacco use and pregnancy) and breath samples for carbon monoxide and alcohol. Self-report may be used in place of urine analyses on a case-by-case bases. Urine sample analyses for tobacco use may only take place at the VTCRI site. Initial Assessment Session and Sampling (Session 1). First, participants will complete the consenting process. The first session will be an assessment session to collect information from participants on patterns and degree of tobacco and other substance use, perceptions of all cigarette types available in the ETM, as well as the results of behavioral and cognitive tasks that we think may inform or complement the results from the main study (see Appendix A for a complete list and descriptions). Participants will also complete the initial sampling period following the initial sampling session. The goal of this period is to familiarize the participants with their randomly assigned cigarette as well as alternative nicotine products. After their assessment session, participants will be given a 7-day supply of ventilated and unventilated (3.5 days of venitlated and 3.5 days of unventialted) cigarettes and asked to use these cigarettes. The actual number of cigarettes delivered to each participant will be determined by multiplying their reported cigarettes smoked per day by 7. Therefore, the average minimum number of cigarettes that will be delivered is approximately 70 (10 cigarettes per day minimum to qualify to participate). They will be also be given a sample of the alternative nicotine products that will be made available during the Real-ETM sessions. Participants will be asked to report their favorite flavor of each product to sample. If the participant is naïve to the alternative nicotine product, they will be asked to estimate which product flavor they would prefer. To verify usage during this and all subsequent usage period (see below), participants will be asked to return spent cigarette filters in resealable bags we provide. However, while participants will be asked to smoke the cigarettes they are given and to not use any other cigarettes, they will only be asked to try the alternative nicotine products during the sampling period, they do not have to finish them. A subset of these spent filters will be randomly chosen and analyzed to permit correlation of mouth-level exposure to smoke constituents with differences in ETM purchasing behavior between ventilated and unventilated cigarettes. During this sampling period, participants will go about their daily lives, allowing them to sample these cigarettes in the social environment in which they typically operate. This "real-world" sampling period will serve to increase the generalizability of the results obtained in the ETM sessions. This duration of exposure was chosen to give participants time to begin to familiarize themselves with their assigned cigarettes. This will enable them to make informed purchasing decisions during the upcoming sessions. Real Experimental Tobacco Marketplace Sessions (Sessions 2,6, and 10). Following the initial sampling period, participants will complete a purchasing session in our realistic tobacco product marketplace. Participants will be seated in front of a computer to access an online marketplace with an interface similar to many online merchants. This will allow participants to browse through the products and add as many as they desire to the virtual shopping cart. Each product will have the price clearly displayed along with an image. Each ETM session will contain five pricing scenarios, in which we: i. manipulate the price of participants' assigned cigarettes to assess demand in a context with no other products available; ii. manipulate the price of participants' non-assigned cigarettes to assess demand in a context with no other products available; iii. manipulate the price of both assigned and non-assigned cigarettes in unison to assess simple preference between the two; iv. manipulate the price of participants' assigned cigarettes while the price of non-assigned cigarettes remains constant to assess the degree to which assigned cigarettes substitute for non-assigned cigarettes; a. In this task, alternative nicotine products (e.g., e-cigarettes, chew, etc.) may also be available for purchase at a constant price. v. manipulate the price of participants' non-assigned cigarette while the price of assigned cigarettes remains constant to assess the degree to which non-assigned cigarettes substitute for assigned cigarettes. a. In this task, alternative nicotine products (e.g., e-cigarettes, chew, etc.) may also be available for purchase at a constant price. In each of these scenarios, the price-manipulated cigarettes will be available across a range of prices (e.g., $0.12, $0.25, $0.50, $1.00, $2.00, and $4.00). Price-constant cigarettes will be set to the median cigarette price in the community. Participants will use an experimentally provided income (proportional to their real-world tobacco consumption) to purchase from the ETM. At each price, participants will be asked to make seven days of tobacco-product purchases from the ETM. After all 5 scenarios are complete for their assigned cigarette, participants will receive the products they purchased from one randomly selected price. Participants will be well informed of these procedures prior to purchasing. For those seven days after marketplace sessions, participants will be asked to only use those products they have purchased from the tobacco marketplace, and to not purchase any outside tobacco products, to not sell or give away any of their purchases, and to not ask anybody else to purchase products for them. We will strongly encourage participants to follow these procedures, and to report any deviations from these procedures, which we will incorporate into our statistical analyses. If the participant does not spend their entire income, they will be allowed to keep the remainder. In this way, participants will be spending real money and incurring a financial cost for their purchases, leading to more realistic product selections. Following the seven days of using cigarettes obtained from the ETM, participants will again visit the lab to return any unused products and report the use of experimenter provided and non-experimenter provided tobacco products. Extended Cigarette Exposure and Experimental Tobacco Marketplace Testing (Sessions 3, 4, 5, 7, 8, and 9). Following the first session in the ETM and its associated period of tobacco product use, participants will begin periods of freely provided exposure to their assigned cigarette (ventilated or unventilated), alternating with two additional sessions in the ETM at regular intervals. The purpose of this additional exposure between discrete ETM assessments is so that we may examine the effects of sustained exposure to participants' assigned cigarettes at regular intervals. During the extended-exposure periods, participants will visit the lab every 7 days. At each of these sessions during extended-exposure periods, they will return any unused cigarettes, report the use of experimenter provided and non-experimenter provided tobacco products, receive cigarettes for the upcoming 7 days, and complete many of the assessments they completed at their initial assessment session. Following sessions 5 and 9 (the sessions immediately before the Real ETM sessions) participants will be given 6 days of their assigned cigarettes and 1 day of the unassigned cigarettes in order to expose the participant to the unassigned cigarettes before the Real ETM session. An abbreviated set of assessments will be collected on a weekly basis throughout the experiment (Appendix A) in addition to any additional scheduled session (e.g., Real ETM). These assessments will focus on measuring tobacco product use and measures of dependence and withdrawal, including a Timeline Follow-Back for the period since the last session, as well as product perceptions. We will also include a purely hypothetical version of the ETM (on non-real ETM sessions), in which participants do not receive products purchased to use outside the laboratory. Because these hypothetical ETM assessments can be repeated with greater frequency and without interrupting periods of continuous exposure to assigned cigarettes, data from hypothetical assessments will be used to inform determinations of the effects of time on valuation of ventilated and unventilated cigarettes in more detail than primary ETM assessments.


143 patients




21 to 65 years old


Accepts Healthy Volunteers

Inclusion criteria

  • Current cigarette smoker
  • Stable mental and physical health
  • Does not take medications that interfere with nicotine metabolism

Exclusion criteria

  • Pregnant or lactating
  • Immediate future plans to quit smoking

Trial design

143 participants in 2 patient groups

Ventilated cigarettes
Experimental group
Participants in this ARM will be assigned to ~25% filter ventilation commercially available cigarettes.
Other: Commercially available cigarette
Unventilated cigarettes
Experimental group
Participants in this ARM will be assigned to ~0% filter ventilation commercially available cigarettes.
Other: Commercially available cigarette

Trial documents

Trial contacts and locations



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