Smoking CessationPhase 2NCT05994703
Assisting Smokers to Switch to an e-Cigarette by Accelerating Learning of Adaptive Habits Using D-cycloserine
A Phase 2 study testing d-cycloserine and Juul e-cigarette in people with Smoking Cessation and Harm Reduction, run by Rose Research Center, LLC at 2 sites in United States.
Trial summary
This study will evaluate the effects of a reward devaluation strategy, which has been researched in the past, combined/augmented with the medication d-cycloserine in assisting smokers to switch from combustible cigarette (CC) to Juul. Read more about this study
- Who is it for?
- Ages 22 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Smoking Cessation, Harm Reduction
- What is being tested?
- d-cycloserine and Juul e-cigarette
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 2 sitesUnited States
- Study dates
- 20 Oct 2023to 12 Jan 2026
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 22 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Has signed the informed consent form (ICF) and is able to understand the information provided in the ICF.
- Is 22 to 65 years of age (inclusive) at screening.
- Smokes ≥ 10 commercially available CCs per day (no brand restrictions), for the last 12 months.
- Expired air CO reading of at least 10 ppm as assessed at the screening session.
- Interested in switching to an electronic cigarette.
- Willing and able to comply with the requirements of the study.
- Owns a smart phone with text message and data capabilities compatible with necessary surveys.
Who cannot join
- Is unhealthy or cannot participate in the study for any reason (e.g., medical, psychiatric, and/or social reason) as judged by the Investigator or designated medical staff based on all available assessments from the screening period (e.g., safety laboratory, vital signs, physical examination, ECG, concomitant medications and medical history).
- Patient Health Questionnaire (PHQ-9) score greater than 9, or a score greater than 0 on item #9 ("Thoughts that you would be better off dead, or of hurting yourself in some way") at screening.
- Planned use of an FDA-approved smoking cessation product during the study.
- High Blood Pressure (systolic >150 mm Hg, diastolic >95 mm Hg) at screening.
- Body mass index (BMI) less than 15.0 kg/m2 or greater than 40.0 kg/m2.
- Coronary heart disease, structural cardiac disease (including, but not limited to valvular heart disease or cardiac murmurs), cardiac dysrhythmias, syncope, cardiac chest pain, or history of heart attack or heart failure.
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- Has received psychotherapy or behavioral treatments within 30 days of screening, or during the study.
- Taking antidepressants or psychoactive medications (e.g., antipsychotics, antidepressants, benzodiazepines, hypnotics).
- Use of any of these products in the past 30 days:
- Illegal drugs (or if the urine drug screen is positive for cocaine, tetrahydrocannabinol (THC), amphetamines, methamphetamines, or opiates);
- Experimental (investigational) drugs that are unknown to participant;
- Chronic opiate use;
- Medications to treat tuberculosis (e.g., isoniazid, ethionamide).
- Use of smokeless tobacco (chewing tobacco, snuff), cigars (except for "Black \& Mild" cigars or Cigarillos), pipes, hookah, e-cigarettes, nicotine replacement therapy or other smoking cessation treatments within 14 days of screening.
- Pregnant or nursing (by self-report) or positive pregnancy test.
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Rose Research Center
Charlotte, North Carolina, 28262
Rose Research Center
Raleigh, North Carolina, 27617
About this study
This study will evaluate the effects of a reward devaluation strategy, which has been researched in the past, combined/augmented with the medication d-cycloserine in assisting smokers to switch from combustible cigarette (CC) to Juul.
- Conditions
- Smoking Cessation, Harm Reduction
- Being tested
- d-cycloserine, Juul e-cigarette
- Medical subject headings
- Smoking Cessation, Harm Reduction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
d-cycloserineDrug
d-cycloserine (DCS) 100 mg taken orally, once a day for six weeks.
Juul e-cigaretteOther
Juul use as often as the participant likes for 12 weeks.
| Study group | Role | What they receive |
|---|---|---|
| DCS with Juul e-cigarette | Experimental | d-cycloserine (DCS) 100 mg taken orally, once a day for six weeks. There will be a 50 mg dose taken the afternoon/evening prior to the first switch date (after enrollment) to ensure serum levels of the medication are available for the first switch to e-cigarette attempt.
Participants will be instructed to use the Juul as often as they like during the 12 week period, and to switch completely to the Juul within 1 week. If, however, they do smoke any combustible cigarettes (CC), they will also be instructed to use the Juul immediately before each CC to relieve their craving as much as possible before smoking their usual brand. The Juul will also be the first product that they are instructed to use each morning. Smokers will be told to try to completely substitute Juul for CCs by the end of the first week of use. Receives: Drug: d-cycloserine; Other: Juul e-cigarette |
What is being measured
The primary outcome is the main question the study is designed to answer.
Smoking Abstinence based on Self-Report
Complete switching from combustible cigarette use at each time point will be defined by a self-report of no cigarette smoking (not even a puff) since the prior session.
Measured: During weeks 3-6 and 9-12 post-switching date.
Smoking Abstinence based on Expired Air Carbon Monoxide (CO)
Complete switching from combustible cigarette use at each time point will be confirmed by an expired air CO reading of less than 5 ppm.
Measured: End of Week 6, End of Week 12
Secondary outcomes (3)
Reduction in Cigarettes Per Day
Reduction in the number of reports cigarettes smoked per day over the previous seven days (at each time point) compared to baseline.
Measured: Week 6, Week 12, Six-Month Follow-Up
Reduction in Expired Air Carbon Monoxide (CO)
Reduction in Expired Air Carbon Monoxide (CO) compared to baseline.
Measured: End of Week 6, End of Week 12
Change in rewarding effects for cigarettes and e-cigarettes at 6 weeks post switch
- assess subjective satisfaction and other perceived rewarding or aversive effects accompanying e-cigarette use and combustible cigarette use using the modified (e-Cigarette) Cigarette Evaluation Questionnaire. This questionnaire contains five subscale scores: smoking satisfaction (satisfying, tastes good, enjoy smoking), psychological rewards (calms down, more awake, less irritable, helps concentrate, reduces hunger), aversion (dizziness, nauseated), enjoyment of respiratory tract sensations (single-item assessment), craving reduction (single-item assessment). Participants will be asked to assess the 12 items of the questionnaire on a 7-point scale, ranging from "1-not at all" to "7-extremely".
Measured: End of Week 6
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Aug 2023
- Study start20 Oct 2023
- Primary completion13 Oct 2025
- Study completion12 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Smoking CessationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Rose Research Center, LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Foundation for a Smoke Free World INC
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05994703
- Sponsor's protocol ID
- CYCLE
- Status last verified
- Jan 2026
- First submitted
- 24 Jul 2023
- Last updated
- 20 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assisting Smokers to Switch to an e-Cigarette by Accelerating Learning of Adaptive Habits Using D-cycloserine
- ClinicalTrials.gov ID
- NCT05994703
- Acronym / sponsor ID
- CYCLE
- Conditions
- Smoking Cessation, Harm Reduction
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 25 participants (actual)
- Lead sponsor
- Rose Research Center, LLCIndustry (pharma, biotech, devices)
- Collaborators
- Foundation for a Smoke Free World INC
- Study start
- 20 Oct 2023 (actual)
- Primary completion
- 13 Oct 2025 (actual)
- Study completion
- 12 Jan 2026 (actual)
- First posted
- 16 Aug 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the effects of a reward devaluation strategy, which has been researched in the past, combined/augmented with the medication d-cycloserine in assisting smokers to switch from combustible cigarette (CC) to Juul.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| DCS with Juul e-cigarette | Experimental | Drug: d-cycloserine, Other: Juul e-cigaretted-cycloserine (DCS) 100 mg taken orally, once a day for six weeks. There will be a 50 mg dose taken the afternoon/evening prior to the first switch date (after enrollment) to ensure serum levels of the medication are available for the first switch to e-cigarette attempt. Participants will be instructed to use the Juul as often as they like during the 12 week period, and to switch completely to the Juul within 1 week. If, however, they do smoke any combustible cigarettes (CC), they will also be instructed to use the Juul immediately before each CC to relieve their craving as much as possible before smoking their usual brand. The Juul will also be the first product that they are instructed to use each morning. Smokers will be told to try to completely substitute Juul for CCs by the end of the first week of use. |
Who may qualify
- Ages
- 22 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Has signed the informed consent form (ICF) and is able to understand the information provided in the ICF.
- Is 22 to 65 years of age (inclusive) at screening.
- Smokes ≥ 10 commercially available CCs per day (no brand restrictions), for the last 12 months.
- Expired air CO reading of at least 10 ppm as assessed at the screening session.
- Interested in switching to an electronic cigarette.
Key exclusion criteria (15 listed)
- Is unhealthy or cannot participate in the study for any reason (e.g., medical, psychiatric, and/or social reason) as judged by the Investigator or designated medical staff based on all available assessments from the screening period (e.g., safety laboratory, vital signs, physical examination, ECG, concomitant medications and medical history).
- Patient Health Questionnaire (PHQ-9) score greater than 9, or a score greater than 0 on item #9 ("Thoughts that you would be better off dead, or of hurting yourself in some way") at screening.
- Planned use of an FDA-approved smoking cessation product during the study.
- High Blood Pressure (systolic >150 mm Hg, diastolic >95 mm Hg) at screening.
- Body mass index (BMI) less than 15.0 kg/m2 or greater than 40.0 kg/m2.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| d-cycloserined-cycloserine (DCS) 100 mg taken orally, once a day for six weeks. | Drug | DCS with Juul e-cigarette |
| Juul e-cigaretteJuul use as often as the participant likes for 12 weeks. | Other | DCS with Juul e-cigarette |
Primary outcome
Smoking Abstinence based on Self-Report
Time frame: During weeks 3-6 and 9-12 post-switching date.
Complete switching from combustible cigarette use at each time point will be defined by a self-report of no cigarette smoking (not even a puff) since the prior session.
Smoking Abstinence based on Expired Air Carbon Monoxide (CO)
Time frame: End of Week 6, End of Week 12
Complete switching from combustible cigarette use at each time point will be confirmed by an expired air CO reading of less than 5 ppm.
3 secondary outcomes
Reduction in Cigarettes Per Day
Time frame: Week 6, Week 12, Six-Month Follow-Up
Reduction in Expired Air Carbon Monoxide (CO)
Time frame: End of Week 6, End of Week 12
Change in rewarding effects for cigarettes and e-cigarettes at 6 weeks post switch
Time frame: End of Week 6
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Jan 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing d-cycloserine and Juul e-cigarette in people with Smoking Cessation and Harm Reduction, run by Rose Research Center, LLC at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 20 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Smoking Abstinence based on Self-Report (time frame: During weeks 3-6 and 9-12 post-switching date.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Jan 2026.