The purpose of this research program is to understand how a biomarker called the "nicotine metabolite ratio" (also referred to as NMR) may influence a smoker's ability to quit smoking.
Smoking is an enormous public health problem with a great need for research to improve treatment outcomes. Our prior data indicates that the cytochrome P450 2A6 (CYP2A6) enzyme is critical in the metabolic inactivation of nicotine, and also influences smoking behavior and response to therapies. With a vision toward translation of our research to practice, we have characterized a genetically-informed biomarker of CYP2A6 activity, specifically the nicotine metabolite ratio (NMR; 3'hydroxycotinine/cotinine), which reflects both CYP2A6 genetic variation and environmental influences on CYP2A6 activity. The NMR is measured non-invasively in smokers with established reliability, stability, analytic validity, and efficacy as a predictor of the ability to quit smoking and treatment response in multiple retrospective trials. Translation of these findings to clinical practice requires validation in a prospective clinical trial comparing alternative therapies for smoking cessation. Thus, the proposed trial is a prospective, stratified, placebo-controlled, multi-center clinical trial of alternative therapies for smoking cessation treatment in approximately 1,200 smokers. Randomization to placebo (PLA), transdermal nicotine (TN), or varenicline (VAR) will be stratified prospectively based on the nicotine metabolite ratio (NMR). Abstinence from smoking at the end of treatment will be the primary outcome. Quit rate at 6-month follow-up is a secondary outcome. To facilitate translation to practice, analysis of the cost-effectiveness of our proposed approach will also be completed. The proposed research provides the next critical step to validate a genetically-informed diagnostic tool, the NMR, which clinicians can use in the future to optimize treatment decisions for their patients who wish to quit smoking.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
1,246
Day 1-3: 0.5mg once daily orally Day 4-7: 0.5mg twice daily orally Day 8-84: 1.0mg twice daily orally
Day 1-3: 0.5mg once daily orally Day 4-7: 0.5mg twice daily orally Day 8-84: 1.0mg twice daily orally Week 1 - 6: 21mg placebo patch Week 7 - 8: 14mg placebo patch Week 9 - 11: 7mg placebo patch
Week 1-6: 21mg nicotine patch Week 7-8: 14mg nicotine patch Week 9-11: 7mg nicotine patch
University at Buffalo - State University of New York
Buffalo, New York, United States
Center for Interdisciplinary Research on Nicotine Addiction, University of Pennsylvania
Philadelphia, Pennsylvania, United States
MD Anderson Cancer Center, University of Texas
Houston, Texas, United States
Centre for Addiction and Mental Health, University of Toronto
Toronto, Ontario, Canada
7-day Point Prevalence Quit Rate at End-of-Treatment (EOT)
The percentage of ITT subjects who were verified as abstinent. Abstinence was defined as no self-reported smoking (not even a puff) for at least 7 days before the telephone assessment, with in-person verification for those self-reporting abstinence. In-person verification consisted of breath carbon monoxide analysis, with a reading of 8 parts-per-million or less confirming abstinence. Subjects who were lost to follow-up were considered smokers.
Time frame: Week 11
7-day Point Prevalence Quit Rate at 6-month Follow up Survey
The percentage of ITT subjects who were verified as abstinent at the 6-month follow up survey. Abstinence was defined as no self-reported smoking (not even a puff) for at least 7 days before the telephone assessment, with in-person verification for those self-reporting abstinence. In-person verification consisted of breath carbon monoxide analysis, with a reading of 8 parts-per-million or less confirming abstinence. Subjects who were lost to follow-up were considered smokers.
Time frame: Week 24
Total Side-Effect Severity Index at Pre-Quit
The mean side-effect severity score by treatment group (placebo vs. nicotine patch vs. varenicline) and by NMR group (slow metabolizers vs. normal metabolizers). Side-effect severity was calculated using a Side Effects Checklists (SEC). 29 common side-effects associated with transdermal nicotine or varenicline treatment were rated by participants on a 0 (none) to 3 (severe) scale. For each participant at this timepoint, these scores were summed to calculate a total score, with a range of 0 to 87; a higher score indicated a higher severity of side-effects.
Time frame: Pre-Quit (Week -1/Baseline)
Total Side-Effect Severity Index at Target Quit Date
The mean side-effect severity score by treatment group (placebo vs. nicotine patch vs. varenicline) and by NMR group (slow metabolizers vs. normal metabolizers). Side-effect severity was calculated using a Side Effects Checklists (SEC). 29 common side-effects associated with transdermal nicotine or varenicline treatment were rated by participants on a 0 (none) to 3 (severe) scale. For each participant at this timepoint, these scores were summed to calculate a total score, with a range of 0 to 87; a higher score indicated a higher severity of side-effects.
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Time frame: Target Quit Date (Week 0)
Total Side-Effect Severity Index at Week 1
The mean side-effect severity score by treatment group (placebo vs. nicotine patch vs. varenicline) and by NMR group (slow metabolizers vs. normal metabolizers). Side-effect severity was calculated using a Side Effects Checklists (SEC). 29 common side-effects associated with transdermal nicotine or varenicline treatment were rated by participants on a 0 (none) to 3 (severe) scale. For each participant at this timepoint, these scores were summed to calculate a total score, with a range of 0 to 87; a higher score indicated a higher severity of side-effects.
Time frame: Week 1
Total Side-Effect Severity Index at Week 4
The mean side-effect severity score by treatment group (placebo vs. nicotine patch vs. varenicline) and by NMR group (slow metabolizers vs. normal metabolizers). Side-effect severity was calculated using a Side Effects Checklists (SEC). 29 common side-effects associated with transdermal nicotine or varenicline treatment were rated by participants on a 0 (none) to 3 (severe) scale. For each participant at this timepoint, these scores were summed to calculate a total score, with a range of 0 to 87; a higher score indicated a higher severity of side-effects.
Time frame: Week 4