The Role of Flavor in the Substitutability of E-cigarettes for Combustible Cigarettes Among Persistent Smokers

February 17, 2026 updated by: Janet E. Audrain-McGovern, PhD, Abramson Cancer Center at Penn Medicine
This between-subjects study aims to evaluate the effect of flavor on initial and sustained switching from combustible cigarettes to e-cigarettes among 210 cigarette smokers. After measuring baseline cigarette smoking rate, participants will be randomized to a six-week regimen of fruit-flavored, tobacco-flavored, or menthol-flavored e-cigarettes and be instructed to switch (versus smoking cigarettes) over a 6-week period. Flavor-associated subjective reward and the reinforcing value of flavored e-cigarettes relative to combustible cigarettes will be assessed as mechanisms.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The average smoker will attempt to quit smoking at least 30 times before abstaining for 12 months or longer. These attempts typically occur over decades of smoking, carcinogen and toxicant exposure, resulting in 480,000 deaths annually. As highlighted in the Surgeon General's Report, helping smokers who cannot quit smoking switch to less harmful non-combustible nicotine-containing products, such as e-cigarettes, has the potential to reduce this health burden dramatically. Substituting e-cigarettes for combustible cigarettes might only be possible for persistent smokers if e-cigarettes are accessible and appealing. Harm reduction proponents have advocated for the continued availability of e-cigarette flavors to appeal to and aid cigarette smokers unable to quit with traditional methods. Yet, there are no prospective studies of the effect of flavor on initial and sustained switching from combustible to electronic cigarettes. Converging laboratory, epidemiological, and clinical research suggests that fruit-flavored e-cigarettes with nicotine may be a viable substitute for combustible cigarettes among persistent smokers. The proposed study seeks to answer two novel questions relevant to public health and the regulation of e-cigarette flavoring. First, do persistent smokers substitute fruit-flavored e- cigarettes more readily than traditional-flavored e-cigarettes (tobacco or menthol) for combustible cigarettes? Second, are fruit-flavored e-cigarettes more rewarding and reinforcing than traditional-flavored e-cigarettes, and do these effects facilitate switching? The proposed research will fill these gaps in the evidence base by randomizing 210 persistent cigarette smokers to a six-week regimen of fruit-flavored (FF: watermelon and blueberry, n=70), tobacco-flavored (TF n=70) or menthol-flavored (MF n=70) e-cigarettes in a between-subjects design. Baseline smoking rate will be established during days 1-5. After biochemically verified overnight cigarette smoking abstinence, laboratory visits on days 6 and 7 will assess flavor-associated subjective reward and the reinforcing value of flavored e-cigarettes relative to combustible cigarettes. Participants will then switch from cigarette smoking to e-cigarette use for six weeks. Participants will collect spent cigarette filters daily to assess cigarettes smoked per day (cpd) if they smoke. The primary outcome measure is the longitudinal daily count of cigarettes from baseline to the end of the six-week switch period, with cigarettes per day at a 6-month follow-up as a secondary endpoint.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
210

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Able to communicate fluently in English (i.e. speaking, writing, and reading)
  2. Male and female smokers who are > 21 years of age and self-report smoking at least 5 cigarettes (menthol and/or non-menthol) per day for at least the last 12 months
  3. 5 or more failed quit attempts and the use of smoking cessation medication on at least one prior attempt.
  4. Ever use of an e-cigarette
  5. Have a carbon monoxide (CO) greater than 10 ppm
  6. Not using any forms of nicotine regularly other than cigarettes
  7. Be willing to switch to e-cigarettes for 6 weeks and use the assigned flavors
  8. Plan to live in the area for the duration of the study
  9. Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the combined consent and HIPAA form.

Exclusion Criteria:

Smoking Behavior Regular use of nicotine-containing products other than cigarettes (e.g., chewing tobacco, snuff, snus, cigars, e-cigs, etc.). Regular e-cigarette use is defined as greater than 5 days/past 30 days

  1. Participants agreeing to abstain from using nicotine-containing products other than cigarettes for the duration of the study will be considered eligible.
  2. Current enrollment or plans to enroll in a smoking cessation program over the duration of the study.
  3. Current use of smoking cessation medication
  4. Provide a CO breath test reading less than 10 ppm at Intake.

Alcohol and Drug

  1. History of substance abuse (other than nicotine dependence) in the past 12 months.
  2. Current alcohol consumption that exceeds 20 standard drinks/week.
  3. Current use of recreational drugs (other than nicotine and cannabis)
  4. Breath alcohol reading (BrAC) greater than .000 at Intake.

Medical

  1. Women, including all individuals assigned as "female" at birth, who are pregnant, breastfeeding, or planning a pregnancy over the duration of the study period.
  2. Serious or unstable disease within the past year (e.g. cancer, heart disease). Applicable conditions will be evaluated on a case-by-case basis by the Principal Investigator.
  3. Allergies to either propylene glycol or flavor additives

Psychiatric

1. Lifetime history of schizophrenia or psychosis.

General Exclusion

  1. Past, current, anticipated, or pending enrollment in another research program over the study period that could potentially impact subject safety, study data, and/or the study design as determined by the Principal Investigator.
  2. Any medical condition, illness, disorder, adverse event (AE), or concomitant medication that could compromise participant safety or significantly impact study performance as determined by the Principal Investigator. Subjects may be deemed ineligible for any of the aforementioned reasons at any point throughout the study, as well as during the initial telephone screen.
  3. Significant non-compliance with protocol and/or study design as determined by the Principal Investigator and/o. Subjects may be deemed ineligible at any point throughout the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Fruit-flavored E-cigarettes
Participants randomized to fruit-flavored e-cigarettes will be provided with an e-cigarette device and be instructed to switch from smoking combustible cigarettes to using only the study provided e-cigarette device and fruit-flavored nicotine pods. Participants will be able to choose between blueberry or watermelon-flavored pods. They will receive their supply of nicotine pods in 7-day increments, based on baseline smoking behavior.
Other: E-cigarettes
All participants are instructed to switch from smoking combustible cigarettes to using e-cigarettes for 6 weeks. Participants will receive an e-cigarette device and flavored nicotine pods according to their randomly assigned flavor.
Active Comparator: Tobacco-flavored E-cigarettes
Participants randomized to tobacco-flavored e-cigarettes will be provided with an e-cigarette device and be instructed to switch from smoking combustible cigarettes to using only the study provided e-cigarette device and tobacco nicotine pods. Participants will receive their supply of nicotine pods in 7-day increments, based on baseline smoking behavior.
Other: E-cigarettes
All participants are instructed to switch from smoking combustible cigarettes to using e-cigarettes for 6 weeks. Participants will receive an e-cigarette device and flavored nicotine pods according to their randomly assigned flavor.
Active Comparator: Menthol-flavored E-cigarettes
Participants randomized to menthol-flavored e-cigarettes will be provided with an e-cigarette device and be instructed to switch from smoking combustible cigarettes to using only the study provided e-cigarette device and menthol nicotine pods. Participants will receive their supply of nicotine pods in 7-day increments, based on baseline smoking behavior.
Other: E-cigarettes
All participants are instructed to switch from smoking combustible cigarettes to using e-cigarettes for 6 weeks. Participants will receive an e-cigarette device and flavored nicotine pods according to their randomly assigned flavor.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Cigarette Consumption
Time Frame: 42 days (days 8 - 49)
The primary outcome is the longitudinal daily count of cigarettes from baseline to the end of the e-cigarette switch phase. Daily cigarette consumption will be determined by counting the daily spent cigarette filters returned for each of the 42 days (days 8 - 49).
42 days (days 8 - 49)
Cigarette Smoking Behavior
Time Frame: 19 Weeks (Day 50-6-Month Follow-Up)
Cigarette smoking behavior at the 6-month follow-up will serve as a secondary endpoint.
19 Weeks (Day 50-6-Month Follow-Up)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Abramson Cancer Center at Penn Medicine

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Cancer Institute (NCI)
University of Pennsylvania

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Janet Audrain-McGovern, Ph.D., University of Pennsylvania

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 26, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 8, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 8, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 16, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 19, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • UPCC 11023
  • 854051 (Other Identifier: University of Pennsylvania IRB Protocol Number)
  • R01CA287474-01 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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