Varenicline for smoking cessation

Evidence-based recommendations on varenicline (Champix) for adults who want to stop smoking.

# Guidance
Varenicline is recommended within its licensed indications as an option for smokers who have expressed a desire to quit smoking.
Varenicline should normally be prescribed only as part of a programme of behavioural support.# The technology
Varenicline (Champix, Pfizer) has marketing authorisation for smoking cessation in adults. The summary of product characteristics (SPC) states that smokers should set a date to stop smoking and treatment with varenicline should start 1 to 2 weeks before this date and that smoking cessation therapies are more likely to succeed for patients who are provided with additional advice and support.
Varenicline binds with high affinity and selectivity at the 42 neuronal nicotinic acetylcholine receptor, where it acts as a partial agonist. Its binding both alleviates symptoms of craving and withdrawal, and reduces the rewarding and reinforcing effects of smoking by preventing nicotine binding to 42 receptors.
Varenicline may be associated with nausea and other gastrointestinal disorders such as vomiting. For full details of side effects and contraindications, see the SPC.
Varenicline is available in 0.5-mg and 1-mg film-coated tablets. The cost is 54.60 for a 56-blister pack of 0.5- or 1-mg tablets ('British national formulary'  edition 53). A 12-week course of treatment costs about 163.80. The SPC specifies the option of an additional 12 weeks of treatment and the consideration of dose tapering. Costs may vary in different settings because of negotiated procurement discounts.# The manufacturer's submission
The Appraisal Committee (appendix A) considered evidence submitted by the manufacturer of varenicline and a review of this submission by the Evidence Review Group (ERG: appendix B).
The manufacturer's primary analysis compared the standard 12-week course of varenicline with bupropion and nicotine replacement therapy (NRT). The manufacturer identified four randomised controlled trials (RCTs). Two were three-arm trials that compared varenicline, bupropion and placebo (n = 1483 and 1413). Another trial compared maintenance treatment (24-week course of varenicline) with placebo (n = 2416). The manufacturer also presented data from an open-label trial (n = 957) that compared varenicline with NRT.
The two trials that compared varenicline and bupropion showed that the continuous quit rate for weeks 912 was statistically significantly greater for varenicline: odds ratio (OR) 1.93 (95% CI 1.40 to 2.68) and OR 1.90 (95% CI 1.40 to 2.68), respectively. Both trials also showed that the continuous quit rate for varenicline was statistically significantly greater than for placebo: OR 3.85 (95% CI 2.70 to 5.50) and OR 3.85 (95% CI 2.69 to 5.50), respectively. For the longer time horizon of weeks 952, the ORs for varenicline compared with bupropion, respectively for the two trials, were 1.46 (95% CI 0.99 to 2.17) and 1.77 (95% CI 1.19 to 2.63). The maintenance trial that compared 24-week varenicline with placebo showed that the continuous quit rate was statistically significantly greater with varenicline than with placebo: weeks 1324 OR 2.47 (95% CI 1.95 to 3.15); weeks 1352 OR 1.35 (95% CI 1.07 to 1.70). The results of the open-label trial were marked confidential by the manufacturer.
The manufacturer also submitted a meta-analysis of 70 NRT trials, 12 bupropion trials and 4 varenicline trials against control/placebo. The meta-analysis indirectly compared the efficacy of the treatments based on relative treatment effects. This indirect comparison showed that at 12 months varenicline was superior to NRT (OR 1.66 ) and bupropion (OR 1.58 ). Varenicline was also superior at 3 months to both NRT (OR 1.78 ) and bupropion (OR 1.61 ).
The manufacturer presented a cost-effectiveness analysis based on a Markov model. It assumes an individual makes a single quit attempt at the beginning of the model. The individual is followed from this initial quit attempt to various health states and potential comorbidities including lung cancer, asthma exacerbations, chronic obstructive pulmonary disease, stroke and cardiovascular disease. The probabilities of relapsing and developing comorbidities are assumed to decrease over time from smoking cessation. The efficacy rates for the treatments are calculated from the odds ratios derived from the results of the pooled direct clinical trials and the indirect comparison. The probabilities associated with relapse are derived from relative risks reported in US-based long-term longitudinal and cohort studies into smoking and abstinence. The costs and utilities are derived from several published sources. Some health-related utility estimates are based on US data, including baseline health-related utilities.
The base-case analysis showed that over a lifetime horizon varenicline dominated bupropion and NRT  that is, it was cheaper and more effective. Variation of the time horizon used in the analysis showed that, at 20 years and over, varenicline maintained its dominating position. Sensitivity analyses included altering baseline health-related utilities and costs of NRT, and the use of efficacy rates from the direct open-label trial that compared varenicline with NRT. Over a lifetime horizon varenicline dominated NRT and bupropion in all sensitivity analysis.
The ERG noted that the inclusion/exclusion criteria of the meta-analysis in the manufacturer's submission differed from existing analyses by the Cochrane collaboration and considered that they could overestimate the efficacy of varenicline. The ERG also conducted its own meta-analysis and indirect comparison which suggested that the odds ratio for varenicline in comparison with NRT was lower than in the manufacturer's model: OR 1.54 (95% CI 1.10 to 2.16).
The ERG noted that the assumptions included in the model could make external validity questionable. For example, it considered that the assumption of a single quit attempt was a limitation that did not allow consideration of the impact of subsequent quit attempts on costs, morbidity or mortality. In addition, the extrapolation of data on 1-year quit rates to a lifetime is associated with considerable uncertainty surrounding the long-term relapse or abstinence experience of the model cohort. The ERG noted that the use of indirect comparison in the base case was inappropriate given the availability of direct trial evidence. The ERG further identified some computational errors in the calculation of transition probabilities and population calculations. The ERG commented that the method used to convert odds ratios to efficacy rates was not validated and a model constructed around odds ratios would have been more appropriate. The ERG compared the number of life years gained in the model with the results of two published analyses and found no substantial differences.
Full details of all the evidence are in the manufacturer's submission and the ERG report.# Consideration of the evidence
The Appraisal Committee reviewed the data available on the clinical and cost effectiveness of varenicline, having considered evidence on smoking cessation and the value placed on the benefits of varenicline by people who smoke tobacco products and want to quit, those who represent them, and clinical specialists. It was also mindful of the need to take account of the effective use of NHS resources.
The Committee considered the clinical effectiveness evidence presented by the manufacturer. It concluded that the evidence from the direct trials and the systematic reviews carried out by the manufacturer and ERG demonstrated that varenicline was superior to NRT and bupropion in achieving continuous abstinence. The Committee heard from the clinical specialists and patient experts that the success rates with varenicline made it a useful addition to the variety of interventions available in smoking cessation, particularly because many smokers need to make multiple quit attempts. The availability of an additional treatment choice was mentioned by clinical specialists and patient experts as beneficial to those having difficulty maintaining abstinence and avoiding relapse because it enabled them to have more control.
The Committee considered the evidence on the cost effectiveness of varenicline submitted by the manufacturer. The Committee noted the comments of the ERG that the submission was not transparent and possessed limited external validity. The model included an extrapolation of 1-year clinical data to a lifetime horizon and included an assumption of a single quit attempt. The Committee also noted the computational errors identified by the ERG, and noted that the ERG had expressed concerns about a number of other assumptions in the model, in particular the use of US data for baseline risk and the use of all-cause morbidity instead of other-cause morbidity. Nevertheless, the Committee considered that these concerns were not sufficient to undermine the inference that the use of varenicline in smoking cessation was likely to be a cost-effective use of NHS resources.
The Committee heard from clinical specialists about the importance of counselling and support in smoking cessation to reinforce the commitment required to quit smoking. It noted that varenicline had been provided alongside counselling and support in the clinical trials. However, the Committee also heard from the clinical specialists that counselling and support are not always used by people aiming to stop smoking and that pharmacotherapies can be effective in the absence of such programmes. The Committee concluded that varenicline should normally be provided in conjunction with counselling and support, but that if such support is refused or is not available, this should not preclude treatment with varenicline.# Recommendation for further research
The Committee recommends that research is conducted into the long-term effectiveness of smoking cessation interventions with particular reference to relapse rates after completion of treatment.# Related NICE guidance
NICE has issued the following related technology appraisal guidance and clinical guidelines.
Guidance on the use of nicotine replacement therapy (NRT) and bupropion for smoking cessation. NICE technology appraisal guidance 39 (2002). 
Brief interventions and referral for smoking cessation in primary care and other settings. NICE public health intervention guidance 1 (2006).
Workplace health promotion: how to help employees to stop smoking. NICE public health intervention guidance 5 (2007).
Smoking cessation services. NICE public health programme guidance 10 (2007).# Review of guidance
The review date for a technology appraisal refers to the month and year in which the Guidance Executive will consider whether the technology should be reviewed. This decision will be taken in the light of information gathered by the Institute, and in consultation with consultees and commentators.
A review decision on this guidance was made in January 2011.
Andrew DillonChief ExecutiveJuly 2007# Changes after publication
March 2014: implementation section updated to clarify that varenicline is recommended as an option for smoking cessation. Additional minor maintenance update also carried out.
March 2012: minor maintenance# About this guidance
NICE technology appraisal guidance is about the use of new and existing medicines and treatments in the NHS in England and Wales.
This guidance was developed using the NICE single technology appraisal process.
The recommendations from this guideline have been incorporated into the NICE Pathways on COPD and smoking prevention. We have produced a summary of this guidance for patients and carers. Tools to help you put the guidance into practice and information about the evidence it is based on are also available.
Your responsibility
This guidance represents the views of NICE and was arrived at after careful consideration of the evidence available. Healthcare professionals are expected to take it fully into account when exercising their clinical judgement. However, the guidance does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer.
Implementation of this guidance is the responsibility of local commissioners and/or providers. Commissioners and providers are reminded that it is their responsibility to implement the guidance, in their local context, in light of their duties to avoid unlawful discrimination and to have regard to promoting equality of opportunity. Nothing in this guidance should be interpreted in a way which would be inconsistent with compliance with those duties.
Copyright
 National Institute for Health and Clinical Excellence 2007. All rights reserved. NICE copyright material can be downloaded for private research and study, and may be reproduced for educational and not-for-profit purposes. No reproduction by or for commercial organisations, or for commercial purposes, is allowed without the written permission of NICE.