Cost-effectiveness of smoking cessation in Australia with varenicline, a novel pharmacotherapy

Transcription

1 Cost-effectiveness of smoking cessation in Australia with varenicline, a novel pharmacotherapy Alissa Brown 1, Kate Webb 1, Hansoo Kim 1, Danny Liew 2 1 Pfizer Australia Pty Ltd 2 St Vincent s Hospital, University of Melbourne, Australia ISPOR 3 rd Asia-Pacific Conference, Seoul; September 2008

2 Smoking cessation in Australia Bupropion listed on Pharmaceutical Benefits Schedule (PBS) for smoking cessation: February 2001 Nicotine replacement therapy (NRT) not PBS listed Varenicline (Champix ) Novel pharmacotherapy as a short-term aid to smoking cessation Approved for use in Australia in December 2006 Smokers on varenicline were more likely to abstain from smoking (weeks 9 to 52) than smokers on bupropion (RR 1.4; p=0.002) or placebo (RR 2.4; p<0.0001) Gonzales et al JAMA. 296:47-55, Jorenby et al JAMA.296:56-65

3 Cost to the payer: cost-effectiveness BENESCO Global model shows that varenicline dominates bupropion and NRT No Current Morbidity Death (all cause) COPD or Lung Cancer CVD a : Primary event Asthma Exacerbation Death (COPD or Lung Cancer) CVD a Secondary : event Death (CVD) Death (Asthma) 3

4 Study objectives To quantify the long-term effectiveness and cost-effectiveness of varenicline in Australia To demonstrate the cost-effectiveness of varenicline versus bupropion in the Australian setting to the Pharmaceutical Benefits Advisory Committee (PBAC) 4

5 Clinical and cost effectiveness in Australia Decision analytic Markov mortality model developed 5

6 Model parameters All subjects begin in the Smoker state Time horizon was 20 years or age 85 years Cycle length is 1-year Hypothetical cohort of 1,000 smokers Discounting at 5% per annum was applied to outcomes and costs beyond the first year 6

7 Population Initial cohort of smokers aged between 35 and 79 years, stratified by sex and 5-year age-groups Proportional distribution across sex and age strata based on that of Australian smokers (application of Australian population data to smoking prevalence) 1 All motivated to quit smokers 7 1 Australian Institute of Health and Welfare, 2006; Australia Bureau of Statistics National Health Survey, ,

8 Model inputs Probability of quitting smoking Year 1: dependent on intervention 1 Year 2 and over: self-quitting rate independent of initial intervention 2 Probability of relapse after Year 1 Independent of intervention 3 Discontinuation rates Discontinuation rates from key trials and published Australian data 1,4 Costs Drug costs only: varenicline (12 weeks) and bupropion (9 weeks) Gonzales JAMA. 296:47-55; Jorenby JAMA.296:56-65; 2 Hughes Nicotine & Tobacco Research, 5:13-25; 3 Krall et al Nicotine & Tobacco Research. 4: Wetter et al Preventive Medicine 39: Yudkin e al BMJ. 327:28-9; 4 Medicare Australia Statistics 2006; 5 Pharmaceutical Benefits Schedule

9 Model inputs Mortality Percentage of deaths due to smoking in Australia (PAR%) 1 Mortality in ex-smokers and smokers (mortality ex-smokers decreases linearly to non-smokers at 10 years) 2,3 Utilities of smokers and ex-smokers Age and gender specific utilities for smokers and ex-smokers (Quit 15 years) 4 Utilities of ex-smokers linearly increased from 'Smokers' to 'Quit 15yr' over 15 years 9 1 Peto et al., Australian Institute of Health and Welfare, 3 Royal Australian College of General Practitioners 2006, 4 Fiscella & Franks JAMA. 275:

10 Results A Cohort Expected-Value Analysis was utilised Varenicline, versus placebo or bupropion, represents favourable cost-effectiveness for smoking cessation in the Australian setting Comparison Years of life saved QALYS saved Healthcare costs (Drug & MBS costs) Cost per LYS Cost per QALY Varenicline vs. placebo ~$350,000 <$20,000 <$10,000 Bupropion vs. placebo ~ $250,000 <$30,000 <$15,000 Varenicline vs. bupropion ~$90,000 <$7,500 <$5,000 10

11 Conclusions The long-term cost-effectiveness of smoking cessation programs have been clearly demonstrated This conservative model shows varenicline is a cost-effective aid to smoking cessation in Australia: based solely on mortality benefits without capturing the benefits of reduced GP visits or morbidity associated with short-term and long-term smoking cessation 11

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13 Background: Australian system Therapeutic Goods Administration evaluate efficacy and safety Pharmaceutical Benefits Advisory Committee evaluate effectiveness and cost-effectiveness Pharmaceutical Benefits Schedule (PBS) provides subsidised medicines to the Australian population Approximately 80% of medicines are provided through the PBS 13

14 Sensitivity analyses Inclusion of a modest excess annual healthcare cost of $93.05 resulted in a decrease in the ratios: <$5,000 for $LYS <$2,500 for $QALY Equivalence of mortality of ex-smokers and non-smokers at 15 years increased the ratios marginally: <$10,000 for $LYS <$5,000 for $QALY 14