Summary Background There is substantial variability in therapeutic response and adverse effects with pharmacotherapies for tobacco dependence. Biomarkers to optimize treatment choice for individual smokers may improve treatment outcomes.Wetested whether a genetically-informed biomarker of nicotine clearance, the nicotine metabolite ratio (NMR; 3’hydroxycotinine/cotinine), predicts response to nicotine patch vs. varenicline for smoking cessation. Methods AnNMR-stratified multicenter, randomized, placebo-controlled clinical trial was conducted from November 2010-September 2013 at 4 sites. Treatment-seeking smokers (1246: 662 slow metabolizers; 584 normal metabolizers) were randomized to 11-weeks of nicotine patch (active patch + placebo pill), varenicline (active pill + placebo patch), or placebo (placebo pill + patch), plus behavioral counseling; an intent-to-treat analysis was conducted. Participants were followed for 12-months following the target quit date.The primary endpoint was biochemically verified 7-day point prevalence abstinence at the end of treatment (EOT) to estimate the pharmacologic effect of treatment by NMR. Secondary outcomes were side-effects, withdrawal symptoms, and 6- and 12-month abstinence rates. ClinicalTrials.govregistration: NCT01314001 Findings In the longitudinal model including all time points, the NMR-by-treatment interaction was significant (ratio of odds ratios (ORR)=1·96; CI=(1·11, 3·46); p=0·02). The results indicate that varenicline was more efficacious than nicotine patch for normal metabolizers, whilethe efficacy was equivalent for slow metabolizers. In cross-sectional analyses, the interaction was significant at EOT (ORR)=1·89; CI=(1·02, 3·45); p=0·04) andat 6-months (ORR=2·07; CI=(1·01, 4·22); p=0·05), but not at 12-months (p=0·14). An NMR-by-treatment interaction showed that slow (vs. normal) metabolizers reported greater overallside-effects severity with vareniclinevs. placebo (β−1·06; CI=(−2·08, −0·03); p=0·044). Interpretation Treating normal metabolizers with varenicline and slow metabolizers with nicotine patchmayoptimize quit rates while minimizing side-effects. Funding National Institutes of Health

Transdermal nicotine is widely used for smoking cessation, but only ~20% of smokers quit successfully with this medication. Interindividual variability in nicotine metabolism rate may influence treatment response. This study sought to validate, and extend in a larger sample, our previous finding that the ratio of plasma nicotine metabolites 3′-hydroxycotinine (3-HC)/cotinine, a measure of nicotine metabolism rate, predicts response to nicotine patch. A sample of 568 smokers was enrolled in a study that provided counseling and 8-weeks of 21mg nicotine patch. Pretreatment 3-HC/cotinine ratio was examined as a predictor of 7-day point prevalence abstinence, verified with breath carbon monoxide (CO), 8 weeks after the quit date. Controlling for sex, race, age, and nicotine dependence, smokers in the upper 3 quartiles of 3-HC/cotinine ratio (faster metabolizers) were ~50% less likely to be abstinent vs. smokers in the first quartile (slow metabolizers; 28% vs. 42%; OR=. 54 [95% CI: .36-.82], p=.003). Among abstainers, plasma nicotine levels (assessed 1 week after treatment began) decreased linearly across the 3-HC/cotinine ratio (β = −3.38, t[355]=−3.09, p<.05). These data support the value of the 3-HC/cotinine ratio as a biomarker to predict success with transdermal nicotine for smoking cessation.

Background: Tobacco dependence is a chronic, relapsing condition that may require extended treatment. Objective: To assess whether extended transdermal nicotine therapy increases abstinence from tobacco more than standard duration therapy in adult smokers. Design: Parallel randomized placebo-controlled trial from September 2004 to February 2008 (small block randomization scheme, not stratified). Study participants and all research personnel except for the database manager were blinded to randomization. (NCT00364156) Setting: Academic center. Participants: 568 adult smokers. Intervention: Participants were randomized to: standard (8 weeks 21mg Nicoderm CQ, 16 weeks placebo) or extended (24 weeks 21mg Nicoderm CQ) therapy. Measurements: The primary outcome was biochemically-verified point prevalence abstinence at weeks 24 and 52. Secondary outcomes were continuous and prolonged abstinence, lapse and recovery events, cost/additional quitter, and side effects and adherence. Results: At 24 weeks, extended therapy produced higher rates of point prevalence abstinence (31.6% versus 20.3%; Odds Ratio [OR] = 1.81 [1.23-2.66], p = 0.002), prolonged abstinence (41.5% versus 26.9%; OR = 1.97 [1.38-2.82] p = 0.001), and continuous abstinence (19.2% versus 12.6%; OR = 1.64 [1.04-2.60] p = 0.032), versus standard therapy. Extended therapy reduced the risk for a lapse (Hazard Ratio [HR] = 0.77 [0.63-0.95], p = 0.013) and increased the chances of recovery from lapses (HR = 1.47 [1.17-1.84], p = 0.001). Time to relapse was slower with extended versus standard therapy (HR = 0.50 [0.35-0.73], p < 0.001). At week 52, extended therapy produced higher quit rates for prolonged abstinence only (p = 0.027). There were no group differences in side effects and adverse events at the extended treatment phase assessment. Limitations: The generalizability of the findings may be limited because participants were treatment-seeking smokers without medical comorbidity and differences in adherence across treatment arms were detected. Conclusion: Compared to 8 weeks of transdermal nicotine, 24 weeks of transdermal nicotine increased biochemically-confirmed point prevalence abstinence and continuous abstinence at week 24, reduced the risk of smoking lapses, and increased the likelihood of post-lapse recovery to abstinence.

While training physicians to provide smoking cessation treatment to cancer patients can enhance physician adherence to clinical practice guidelines, physician smoking cessation interventions fail to yield significant gains in long-term quit rates among cancer patients.

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Background The ratio of 3′hydroxycotinine to cotinine, or nicotine metabolite ratio (NMR), is strongly associated with CYP2A6 genotype, CYP2A6-mediated nicotine and cotinine metabolism, and nicotine clearance. Higher NMR (faster nicotine clearance) is associated retrospectively with heavier smoking and lower cessation rates. Methods NMR as a predictive biomarker of cessation outcomes is being investigated (NCT01314001). In addition to strong CYP2A6-genetic influences on NMR, demographic and hormonal factors alter NMR. Here we analyzed, for the first time together, these sources of variation on NMR in smokers screened for this clinical trial (N=1672). Results Participants (mean age=45.9) were 65.1% Caucasian, 34.9% African American, and 54.8% male. Mean NMR (SD) was higher in Caucasians vs. African Americans (0.41(0.20) vs. 0.33(0.21); P<0.001), and in females vs. males (0.41(0.22) vs. 0.37(0.20); P<0.001). Among females, birth control pill use (N=17) and hormone replacement therapy (N=14) were associated with 19.5% (P=0.09) and 29.3% (P=0.06) higher mean NMR, respectively, albeit non-significantly. BMI was negatively associated with NMR (Rho=−0.14; P<0.001), while alcohol use (Rho=0.11; P<0.001) and cigarette consumption (Rho=0.12; P<0.001) were positively associated with NMR. NMR was 16% percent lower in mentholated cigarette users (P<0.001). When analyzed together in a linear regression model, these predictors (each ≤2%) accounted for <8% of total NMR variation. Conclusions While these factors significantly affected NMR, they contributed little (together <8%; each ≤2%) to total NMR variation. Impact Thus when using NMR, for example to prospectively guide smoking cessation therapy, these sources of variation are unlikely to cause NMR misclassification.

Even though continued smoking by cancer patients adversely affects survival and quality of life, about one third of patients who smoked prior to their diagnosis continue to smoke after their diagnosis. The implementation of smoking cessation treatments for cancer patients has been slowed by the lack of data on correlates of tobacco use in this population. Thus, this longitudinal study assessed demographic, medical, addiction, and psychological predictors of tobacco use among 74 head, neck, and lung cancer patients. Multivariable binary logistic regression analyses, with outcome categorized as smoker or nonsmoker, indicated that the likelihood that patients would be a smoker was associated with lower levels of perceived risk and a higher level of quitting cons. Multivariable nominal logistic regression, with outcome classified as continuous smoker, continuous quitter, relapser, or follow-up quitter, indicated that: (a). patients categorized as continuous smokers reported significantly lower quitting self-efficacy than follow-up quitters and continuous quitters, (b). relapsers reported a significantly lower level of quitting self-efficacy than either follow-up quitters or continuous quitters, and (c). continuous smokers exhibited a significantly lower level of risk perceptions than continuous abstainers. These findings can be useful for the development and evaluation of treatments to promote smoking cessation among cancer patients.

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