Effectiveness and safety of varenicline as an aid to smoking cessation: results of an inter-Asian observational study in real-world clinical practice

Identifying determinants of varenicline adherence using the Theoretical Domains framework: a rapid review

BACKGROUND

Adhering to varenicline has been shown to significantly improve the chances of successfully quitting smoking, with studies indicating a twofold increase in 6-month quit rates. However, despite its potential benefits, many individuals struggle with maintaining good adherence to varenicline; thus there is a need to develop scalable strategies to help people adhere. As a first step to inform the development of an intervention to improve adherence to varenicline, we conducted a rapid literature review to identify: 1) modifiable barriers and facilitators to varenicline adherence, and 2) behaviour change techniques associated with increased adherence to varenicline.

METHODS

We searched MEDLINE, Embase, APA PsycINFO, CINAHL, and the Cochrane Central Register of Controlled Trials for relevant studies published between 2006 and 2022. Search terms included "varenicline," "smoking cessation," and "adherence," and their respective subject headings and synonyms. We screened and included studies reporting modifiable determinants of adherence to varenicline and then assessed quality, extracted modifiable determinants and mapped them to the Theoretical Domains Framework version 2 and the Behaviour Change Technique Taxonomy version 1.

RESULTS

A total of 1,221 titles were identified through the database searches; 61 met the eligibility criteria. Most of the studies were randomized controlled trials and predominantly focused on barriers to varenicline. Only nine studies explicitly mentioned behaviour change techniques used to help varenicline adherence. Eight domains were identified as barriers to varenicline adherence (behavioural regulation, memory, goals, intentions, beliefs about capabilities, beliefs about consequences, optimism/pessimism, and environmental context) and five as facilitators (knowledge, behavioural regulation, beliefs about capabilities, social influences, and environmental context).

CONCLUSIONS

This study identifies barriers and facilitators that should be addressed when developing a complex adherence intervention tailored to patients' needs based on modifiable determinants of medication adherence, some of which are under- used by existing adherence interventions. The findings from this review will inform the design of a theory-based healthbot planned to improve varenicline adherence in people undergoing smoking cessation treatment.

SYSTEMATIC REVIEW REGISTRATION

This study was registered with PROSPERO (# CRD42022321838).

Harm reduction in tobacco control: where do we draw the line?

With substance abuse, harm reduction refers to reducing or replacing use of a harmful product with a less risky agent. But many advertised "non-pharmaceutical" harm reduction alternatives for tobacco smoking are problematic. Studies have revealed inconclusive results using agents including chewing tobacco and e-cigarettes to quit smoking and have demonstrated continued use of these agents. Many smoking harm reduction agents pose other health risks not found in traditional tobacco smoking. Given these limitations, efforts should focus on promoting nicotine replacement therapy, and other pharmacologic agents with a better chance of producing sustained smoking cessation. To address the harmful nature of many tobacco replacement products, public health should focus on regulating these alternatives with the same stringency as tobacco, and social marketing efforts should target evidence-based and safer pharmaceutical grade or behavioural alternatives.

Safety and Effectiveness of Varenicline in Korean Smokers: A Nationwide Post-Marketing Surveillance Study

PURPOSE

Varenicline has demonstrated its safety and efficacy in Western studies including <3% of Asian participants. This prospective multi-center observational study investigated the safety and effectiveness of varenicline in Korean smokers.

PATIENTS AND METHODS

Smokers prescribed varenicline for the first time were enrolled from 252 medical institutions. Investigators recorded and graded all adverse events (AEs). To assess the effectiveness of varenicline, the 7-day point prevalence (PP) of smoking cessation was evaluated at the four visits during the 12-week treatment course. Rates of AE incidence and smoking cessation were analyzed using Chi-squared test or Fisher's exact test. This study is registered with ClinicalTrials.gov, number NCT00483002.

RESULTS

A total of 3719 and 3700 study subjects were included in the safety and effectiveness analyses, respectively. Overall, 346 (9.3%) subjects experienced 471 AEs: 358 mild, 97 moderate, 9 severe, and 7 serious. The most frequent AEs were nausea (5.1%), dyspepsia (0.8%), abnormal dreams (0.8%), insomnia (0.8%), and headache (0.7%). Among the subjects with AEs, 73 subjects discontinued treatment, of which 68 were due to AE occurrence. The 7-day PP of smoking cessation at weeks 1-2, 3-6, 7-10, and ≥ week 11 were 51.7% (387/749), 59.6% (1740/2922), 73.3% (1114/1520), and 77.0% (1116/1449), respectively (p for trend = 0.023). Comorbidities and allergies were associated with a higher incidence of AEs and lower smoking cessation rate (p < 0.05). Younger subjects, infrequent alcohol drinkers, and lighter smokers showed a higher smoking cessation rate (p < 0.05).

CONCLUSION

Varenicline in adult Korean smokers was well tolerated and effective as a smoking cessation aid in routine clinical practice.

New Biomarkers Based on Smoking-Related Phenotypes for Smoking Cessation Outcomes of Nicotine Replacement Therapy: A Prospective Study

Introduction:

Identifying a potent biomarker for smoking cessation can play a key role in predicting prognosis and improving treatment outcomes. This study aimed to evaluate the contribution of new biomarkers based on the levels of Cotinine (Cot) and carbon monoxide (CO) to the short- and long-term quit rates of nicotine replacement therapies (Nicotine Patch [NP] and Nicotine Lozenge [NL]).

Methods:

In this prospective interventional study, 124 smokers under treatment with the 5A’s method were selected from an outpatient smoking cessation center in district 18 of Tehran City, Iran. The study was conducted from April 2016 to December 2018. They were divided into NP (n=56) and NL (n=61) intervention groups. The levels of Cot and CO were measured using ELISA and breath analysis at the beginning of the study. Three markers were calculated: Cot/CO, Cot to cigarette per day ratio (Cot/CPD), and CO/CPD. Binary logistic regression models and generalized estimating equations models were analyzed by SPSS software, version 21 to determine the chances of quitting smoking.

Results:

Of the NP participants, 30.4% and 19.6% were abstinent after 2 and 6 months, respectively, while NL was found less effective with 19.7% for 2-month follow-up and 13.1% for 6-month follow-up. The 6-month success of quitting attempts was significantly different for the NP participants at the second half of Cot/CO (P=0.029). Of the NL participants, CO/CPD would be a superior predictor for smoking cessation success (P>0.05).

Conclusion:

The findings of this study suggested two markers of Cot/CO and CO/CPD in this order for the optimum treatment outcomes of NP and NL.

Effect of Intensive Personalized "5As+5Rs" Intervention on Smoking Cessation in Hospitalized Acute Coronary Syndrome Patients Not Ready to Quit Immediately: A Randomized Controlled Trial

Introduction

The acute coronary syndrome (ACS) patients who are not ready to quit smoking immediately have an extremely low rate of cessation. This study aims to investigate the efficacy of intensive personalized '5As+5Rs'intervention (IPANR intervention) on smoking cessation in this population.

Methods

A parallel-group randomized controlled trial was carried out, which compared IPANR intervention with routine 5Rs (control) at Fu Xing Hospital, Capital Medical University, Bei Jing, China. Three hundred and twenty hospitalized ACS smokers who were not ready to quit were randomly distributed to IPANR intervention group comprising three individual counseling during hospitalization and 15 intensive follow-up sessions (weekly during months 1, 2, 3, and monthly thereafter until month 6) or 5Rs group in a 1:1 fashion by 8 cardiologists who were blinded to the allocation sequence. Primary end point was carbon monoxide-confirmed continuous abstinence rate (CAR) through week 9 to week 12. Secondary outcome included abstinence rate at 24 weeks.

Results

Overall, 97.5% (312/320) participants completed the trial. An intention-to-treat analysis showed statistically significant advantage of IPANR compared with control group at 4 weeks CAR (27.5% vs. 17.5%, RR = 1.571, 95% CI = 1.032-2.392, p = 0.032, number needed to treat (NNT) = 10), and abstinence rate at 24 weeks (23.8% vs.15.0%, RR 1.583, 95% CI = 0.998-2.512, p = 0.048, NNT: 11.36). At 24 weeks, cigarettes smoked per day by the patients who failed to quit were significant lower in IPANR group than 5Rs group (13.21 ± 8.23 vs. 17.45 ± 10.71; p < 0.001).

Conclusions

The IPANR initiated during hospitalization, is a feasible and effective approach for smoking cessation in ACS patients not ready to quit immediately.

Implications

Smoking has a major impact on acute stages of ACS for recurrent ischemic events and long-term outcomes. However, there are few evidence-based treatments for smokers who are not ready to quit. This study described a cessation intervention initiated during hospitalization and included 15 intensive follow-up aimed at enabling ACS smokers who were not ready to quit immediately to deliver adequate motivational and behavior change counseling. Given its effectiveness demonstrated in this prospective study, this intervention in hospitalized ACS smokers might have the potential to substantially improve the cessation rate of ACS patients who are not ready to quit smoking immediately.

Incidence of Immune-Related Adverse Events with Program Death Receptor-1- and Program Death Receptor-1 Ligand-Directed Therapies in Genitourinary Cancers

Program death receptor-1 (PD-1) and program death receptor-1 ligand (PD-L1) inhibitors are increasingly being used in the clinic to treat a growing number of malignancies, including many genitourinary (GU) malignancies. These immune-based therapies have demonstrated a distinct toxicity profile compared to traditional chemotherapy and the targeted therapies directed at the vascular endothelial growth factor pathway or the mammalian target of rapamycin pathway. Autoimmune toxicity targeting the skin, gastrointestinal tract, or the endocrine organs are some of the more common adverse events (AEs) noted with these therapies. Here in, we report the results of a systematic review of the incidence of toxicities in GU cancers reported in the phase II or phase III clinical trials using single-agent PD-1 or PD-L1 inhibitors. Overall, the rate of serious (grades 3-4) AEs was noted in approximately 15% of patients. The AEs noted were similar between all the agents tested, highlighting the overall class effect of these therapies. The incidence in GU cancers is similar to those seen in other malignancies. Given the widespread and high volume real-world use of these agents, it is important for oncologists to be familiar with these side effects to minimize the risks for patients while undergoing therapy.

Effectiveness of varenicline and counselling for smoking cessation in an observational cohort study in China

OBJECTIVES

To evaluate the effectiveness of varenicline for smoking cessation in Chinese smokers in a real world cessation clinic practice.

DESIGN

A prospective observational study.

SETTING

Beijing, China.

PARTICIPANTS

A total of 924 smokers (883 men and 41 women) who attended a smoking cessation clinic of a large general hospital were assessed with data from structured questionnaires at baseline and follow-up at 1, 3 and 6 months. Trained physician counsellors provided free individual counselling for all subjects and follow-up interviews with brief counselling. 332 subjects additionally prescribed varenicline according to their own choice were compared with those without varenicline.

MAIN OUTCOME MEASURES

Primary outcomes were self-reported 7-day point prevalence abstinence rate and 3-month continuous abstinence rate at 6-month follow-up. Secondary outcomes were 7-day point prevalence abstinence rates at 1 and 3-month follow-up, and 1-month continuous abstinence rate at 3-month follow-up.

RESULTS

By intention-to-treat, the 7-day point prevalence abstinence rate with varenicline and counselling at 6 months was significantly higher than counselling only (37.0% vs 23.1%; OR, 1.75; 95% CI 1.46 to 2.62; p=0.001). The 3-month continuous abstinence rate at 6 months was higher with varenicline (33.1% vs 18.4%; OR, 2.04; 95% CI 1.61 to 2.99; p<0.001). Varenicline also showed better secondary outcomes.

CONCLUSIONS

Varenicline prescription in the smoking cessation clinic appeared to be effective with doubling of quit rates in Chinese smokers in a real world cessation clinic practice.

CLINICAL TRIAL REGISTRATION

NCT01935505; Results.

Gender Differences in Outcome of an Attempt to Stop Smoking Among Smokers Attending a Smoking Cessation Clinic in Taiwan: 3-Year Follow-Up Study

Studies that have examined gender differences in smoking cessation have produced mixed results. The purpose of the study was to examine whether there are gender differences in long-term smoking abstinence rates in smokers treated with nicotine patches at a smoking cessation clinic in Taiwan, where 39% of men and 5% of women smoke. This study included 1,065 smokers, comprising of 940 men and 125 women. Smokers were invited to attend the clinic every 1-2 weeks for a maximum of eight visits over 90 days, where they received prescriptions for nicotine patches, counseling, and educational materials. Participants were contacted by telephone at 1 and 3 years after the first visit and were asked whether they had smoked at all over the past 7 days. The results showed that women were significantly less likely than men to be abstinent at 1 year (adjusted odds ratio [aOR] = 0.64; 95% CI [confidence interval] = [0.41, 0.99]; p = .044) and 3 years (aOR = 0.44; 95% CI = [0.27, 0.74]; p = .02). More effective ways are needed to help female smokers quit in societies where smoking in women is rare and may be associated with social stigma.

Relationship between education levels and booster counselling sessions on smoking cessation among Chinese smokers

OBJECTIVES

Although various effective interventions are available to help individuals quit smoking, the effect of educational levels on cessation rates has rarely been studied, and of the few intervention studies on this topic, the results have been conflicting.

DESIGN AND SETTING

From October 2008 to August 2013, a partly retrospective non-randomised study was conducted in a smoking cessation clinic of a large general hospital in Beijing, China.

PARTICIPANTS

In total, 547 Chinese smokers who sought treatment were divided into two groups: a face-to-face counselling group (FC, n=149) and an FC group subjected to four telephone follow-up sessions (FCF, n=398).

OUTCOMES

We evaluated self-reported cessation rates by day 7 and after 6 and 12 months and stratified the two groups by education levels.

RESULTS

The 7-day and 6-month and 12-month continuous cessation rates of smokers of low education levels in the FC group at the time of the 12-month follow-up were 12.5%, 7.1% and 7.1%, respectively, which were lower than those of the highly educated smokers (16.1%, 12.9% and 9.7%, respectively). The results were opposite for the FCF group. The corresponding results for the highly educated smokers of the FCF group were 25.0%, 17.2% and 10.3%, respectively, which were lower than those for the smokers of low education levels (28.3%, 22.9% and 18.1%, respectively). However, significant differences were observed only among the FCF group participants who had experienced 12 months of continuous abstinence, and the crude OR for these individuals was recorded at 0.52 (0.29 to 0.93), p=0.03. A stepwise logistic regression showed that education levels may play a role in various intervention methods. Being married and higher Fagerström test scores were also predictors of cessation tendencies.

CONCLUSIONS

Education levels may affect the benefits of booster counselling sessions on smoking cessation among Chinese smokers.

The effect of a very brief smoking-reduction intervention in smokers who have no intention to quit: study protocol for a randomized controlled trial

Background

Tobacco use is one of the most common preventable causes of death, but more than half of the Chinese men still use tobacco products. Moreover, 63.6% of Chinese smokers have stated that they would not consider quitting. Specialized and intensive smoking-cessation services are too expensive and passive to have major clinical and public health impacts in developing countries like China. Smoking cessation medications are not covered by medical insurance, and their high price prevents Chinese smokers from using them. Brief interventions are needed to provide cost-effective and timesaving tobacco dependence treatments in China mainland.

Methods/design

We describe a two-arm randomized controlled trial for smokers who have no intention to quit. The project will be conducted in outpatient clinics at a large hospital in Beijing, China. Both arms include one face-to-face interview plus five follow-up interventions. Each intervention will last approximately one minute. Subjects allocated to the smoking-reduction intervention arm (SRI) will be advised to reduce smoking consumption to at least half of their current consumption level within the next month. All subjects in the SRI will be warned to bear in mind that an attempt to reduce smoking is an intermediate step before complete cessation. Smokers who have successfully reduced their smoking consumption will be encouraged to completely cease smoking. Controls are subjects allocated to the exercise- and diet-advice arm (EDA) and will be given advice about healthy diet and physical activity, but the advice will not include smoking cessation or reduction. Data collection will be done at baseline and at each follow-up interview using standardized questionnaires. The primary outcomes include self-reported and biochemically verified 7-day point prevalence and prolonged abstinence rates at 12-month follow-up.

Discussion

We expect that an intention to quit in smoking outpatients can be motivated by physicians in the clinic setting. If this very brief smoking-reduction intervention can be demonstrated to have a positive impact on long-term smoking cessation, this strategy has the potential to be a viable and acceptable approach and may be used widely in China and elsewhere.

Clinical trial registration

ClinicalTrials.gov: NCT02370147 (date of registration: 23th February, 2015).

Smoking cessation in Asians: focus on varenicline

Smoking is a modifiable risk factor for morbidity and mortality caused by cancer, cardiovascular diseases, respiratory diseases, and many other diseases. Given the large population size and high prevalence of smoking in Asia, successful smoking cessation could potentially prevent the large number of premature deaths in Asians. However, most dependent smokers cannot successfully quit smoking due to nicotine addiction, and they need professional help and smoking cessation therapies. Varenicline is a highly selective partial agonist for the nicotinic acetylcholine receptor α4β2 subtype, which is believed to be responsible for mediating the reinforcing properties of nicotine. This article is a narrative review, which summarizes the smoking cessation efficacy, side effects, and cost utilities of varenicline in Asians. From this review, we conclude that varenicline is an effective medication that could assist smoking cessation in the Asian populations. The adverse events of varenicline are tolerable, and the most common events were nausea and abnormal dreams. Both the efficacy and tolerance of varenicline in Asians are similar to that in Western populations. Considering the cost utilities, varenicline should be recommended for use in smoking cessation and be covered by medical insurance in most Asian countries.

Nephrotoxic effects of varenicline as the most effective drug used for smoking cessation: a preliminary experimental study

PURPOSE

Varenicline is a new most effective drug for smoking cessation. Its effect on kidney functions remains unclear. This study purposed to investigate whether varenicline causes nephrotoxicity in rats.

METHODS

Fifteen rats were randomly assigned to three groups: control, 0.0125 mg kg(-1) varenicline and 0.025 mg kg(-1) varenicline (single dose for 3 days, i.p.). Before and after experimental period, serum neutrophil gelatinase-associated lipocalin, creatinine and urea levels were measured. Total oxidant and antioxidant status were measured in kidney homogenates. Histological examination was performed in kidney.

RESULTS

The nephrotoxic effects of varenicline were detected by histopathological and biochemical examinations in the varenicline treatment groups. No change was observed in the control group.

CONCLUSIONS

These findings firstly indicate that a 3-day varenicline treatment causes nephrotoxic effects in rats.

Use of the nicotine metabolite ratio as a genetically informed biomarker of response to nicotine patch or varenicline for smoking cessation: a randomised, double-blind placebo-controlled trial

BACKGROUND

Substantial variability exists in therapeutic response and adverse effects with pharmacotherapies for tobacco dependence. Biomarkers to optimise treatment choice for individual smokers might improve treatment outcomes. We tested whether a genetically informed biomarker of nicotine clearance, the nicotine metabolite ratio (NMR; 3'-hydroxycotinine:cotinine), predicts response to nicotine patch or varenicline for smoking cessation.

METHODS

We undertook NMR-stratified multicentre, randomised, placebo-controlled clinical trial from Nov 16, 2010, to Sept 12, 2014, at four sites. Smokers seeking treatment were randomly assigned by baseline NMR status and study site, in blocks of 12 patients (1:1:1 ratio), to 11 weeks of placebo (placebo pill plus placebo patch), nicotine patch (active patch plus placebo pill), or varenicline (active pill plus placebo patch), plus behavioural counselling. Participants and investigators were masked to group allocation and NMR status. An intention-to-treat analysis was done. Participants were followed up for 12 months after the target quit date. The primary endpoint was biochemically verified 7 day point prevalence abstinence at the end of treatment to estimate the pharmacological effect of treatment by NMR. The trial is registered at ClinicalTrials.gov, number NCT01314001.

FINDINGS

1246 participants (662 slow metabolisers of nicotine, 584 normal metabolisers of nicotine) were enrolled and randomly assigned to the three interventions (408 placebo, 418 nicotine patch, 420 varenicline). At end of treatment, varenicline was more efficacious than nicotine patch in normal metabolisers (OR 2·17, 95% CI 1·38-3·42; p=0·001), but not in slow metabolisers (OR 1·13, 0·74-1·71; p=0·56). In the longitudinal model including all timepoints, the NMR-by-treatment interaction was significant (ratio of odds ratios [ORR] 1·96, 95% CI 1·11-3·46; p=0·02). An NMR-by-treatment interaction showed that slow (vs normal) metabolisers reported greater overall side-effect severity with varenicline versus placebo (β=-1·06, 95% CI -2·08 to -0·03; p=0·044).

INTERPRETATION

Treating normal metabolisers with varenicline and slow metabolisers with nicotine patch could optimise quit rates while minimising side-effects.

FUNDING

National Institutes of Health, Canadian Institutes of Health Research, Abramson Cancer Center, Centre for Addiction and Mental Health Foundation, and Pennsylvania Department of Health.

Single dose varenicline may trigger epileptic activity

Varenicline is a new drug for smoking cessation, and its effect on epilepsy is not clear. The aim of this study was to investigate whether different doses of varenicline cause epileptic activity. Forty rats were randomly assigned to the following eight groups: control, saline, and 0.025, 0.04, 0.1, 0.5, 1, and 2 mg kg(-1) varenicline (single dose, i.p.). EEGs were recorded before the varenicline injection and during the following 240 min. While epileptic discharges were observed on the EEGs of the rats in all of the varenicline-treated groups, motor findings of epileptic seizure were not observed in some rats in these groups except the 1 and 2 mg kg(-1) groups. These findings indicate that different single doses of varenicline cause epileptic activity in rats.

Role of nicotine receptor partial agonists in tobacco cessation

One in three adults in India uses tobacco, a highly addictive substance in one or other form. In addition to prevention of tobacco use, offering evidence-based cessation services to dependent tobacco users constitutes an important approach in addressing this serious public health problem. A combination of behavioral methods and pharmacotherapy has shown the most optimal results in tobacco dependence treatment. Among currently available pharmacological agents, drugs that preferentially act on the α4 β2-nicotinic acetyl choline receptor like varenicline and cytisine appear to have relatively better cessation outcomes. These drugs are in general well tolerated and have minimal drug interactions. The odds of quitting tobacco use are at the very least doubled with the use of partial agonists compared with placebo and the outcomes are also superior when compared to nicotine replacement therapy and bupropion. The poor availability of partial agonists and specifically the cost of varenicline, as well as the lack of safety data for cytisine has limited their use world over, particularly in developing countries. Evidence for the benefit of partial agonists is more robust for smoking rather than smokeless forms of tobacco. Although more studies are needed to demonstrate their effectiveness in different populations of tobacco users, present literature supports the use of partial agonists in addition to behavioral methods for optimal outcome in tobacco dependence.