Assisting Smokers to Switch to an e-Cigarette by Accelerating Learning of Adaptive Habits Using D-cycloserine

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 Overview

• Status: Completed
• Conditions: Smoking Cessation; Harm Reduction
• Intervention / Treatment: Drug: d-cycloserine; Other: Juul e-cigarette

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Charlotte, North Carolina, United States, 28262
      • Rose Research Center
    • Raleigh, North Carolina, United States, 27617
      • Rose Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Has signed the informed consent form (ICF) and is able to understand the information provided in the ICF.
2. Is 22 to 65 years of age (inclusive) at screening.
3. Smokes ≥ 10 commercially available CCs per day (no brand restrictions), for the last 12 months.
4. Expired air CO reading of at least 10 ppm as assessed at the screening session.
5. Interested in switching to an electronic cigarette.
6. Willing and able to comply with the requirements of the study.
7. Owns a smart phone with text message and data capabilities compatible with necessary surveys.

Exclusion Criteria:

1. 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).
2. 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.
3. Planned use of an FDA-approved smoking cessation product during the study.
4. High Blood Pressure (systolic >150 mm Hg, diastolic >95 mm Hg) at screening.
5. Body mass index (BMI) less than 15.0 kg/m2 or greater than 40.0 kg/m2.
6. 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.
7. Has received psychotherapy or behavioral treatments within 30 days of screening, or during the study.
8. Taking antidepressants or psychoactive medications (e.g., antipsychotics, antidepressants, benzodiazepines, hypnotics).

9. Use of any of these products in the past 30 days:

   1. Illegal drugs (or if the urine drug screen is positive for cocaine, tetrahydrocannabinol (THC), amphetamines, methamphetamines, or opiates);
   2. Experimental (investigational) drugs that are unknown to participant;
   3. Chronic opiate use;
   4. Medications to treat tuberculosis (e.g., isoniazid, ethionamide).
10. 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.
11. Pregnant or nursing (by self-report) or positive pregnancy test.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: DCS with Juul e-cigarette; 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.

Drug: d-cycloserine; d-cycloserine (DCS) 100 mg taken orally, once a day for six weeks.; Other: Juul e-cigarette; Juul use as often as the participant likes for 12 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	End of Week 6, End of Week 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	End of Week 6, End of Week 12
Change in rewarding effects for cigarettes and e-cigarettes at 6 weeks post switch	o 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".	End of Week 6

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tolerability of daily use of D-cycloserine in conjunction with Juul	The frequency and severity of adverse events will be tabulated as well as the likelihood of their causal relationship to treatment.	Week 2, Week 6, Week 8, Week 12

Collaborators and Investigators

• Sponsor: Rose Research Center, LLC
• Collaborators: Foundation for a Smoke Free World INC

Study record dates

Study Major Dates

• Study Start (Actual): October 20, 2023
• Primary Completion (Actual): October 13, 2025
• Study Completion (Actual): January 12, 2026

Study Registration Dates

• First Submitted: July 24, 2023
• First Submitted That Met QC Criteria: August 8, 2023
• First Posted (Actual): August 16, 2023

Study Record Updates

• Last Update Posted (Actual): January 20, 2026
• Last Update Submitted That Met QC Criteria: January 15, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Behavior; Health Behavior; Smoking Cessation; Harm Reduction; Amino Acids, Peptides, and Proteins; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Azoles; Amino Acids; Oxazolidinones; Oxazoles; Isoxazoles; Serine; Amino Acids, Neutral; Cycloserine
• Other Study ID Numbers: CYCLE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No