Cost-effectiveness of salmeterol xinafoate/fluticasone propionate combination inhaler in chronic asthma

ABSTRACT Objective: To determine where in the treatment steps recommended by the British Thoracic Society and Scottish Intercollegiate Guidelines Network (BTS/SIGN) Asthma Guideline it is cost-effective to use salmeterol xinafoate/fluticasone propionate combination inhaler (SFC) (Seretide*) compared with other inhaled corti­costeroid (ICS) containing regimens (with and without a long acting beta‑2 agonist (LABA)) for chronic asthma in adults and children. Research design and methods: Meta-analyses of percentage symptom-free days (%SFD) were used within a cost-effectiveness model. Time spent in two asthma control health states, ‘symptom-free’ and ‘with-symptoms’ was used as the measure of differential treatment effectiveness. SFC was compared with varying doses of fluticasone propionate (FP) and beclometasone dipropionate (BDP) with or without a separate salmeterol inhaler, and with the budeson­ide/formoterol combination inhaler (BUD/FORM) (Symbicort†). Drug costs, non-drug costs and quality adjusted life years (QALY) were incorporated into the analyses. Results are presented as cost per QALY ratios and uncertainty explored using probabilistic sensitivity analysis. Results: Compared with an increased dose of FP in adults, SFC either ‘dominates’ (i.e. cheaper and more effective) FP or the cost per QALY is £6852. The cost per QALYs estimated in sensitivity analyses using BDP costs range from £5679 to £15 997. For children the cost per QALY for SFC 50 Evohaler* compared with an increased dose of FP is £15 739. SFC is similarly clinically effective in improving %SFDs compared with FP plus salmeterol delivered in separate inhalers (mean differences for each dose comparison of –3.9 (low) (with a 95% confidence interval (CI): –12.96; 5.16); 4.10 (medium) (95% CI: –3.01; 11.21); –0.4 (high) (95% CI: –8.88; 8.08)) and BUD/FORM (mean difference of 0.40 (95% CI –3.69; 4.49)) in adults, and a cheaper SFC option is available at all doses (annual cost savings range from £18–£427 per patient). SFC was similarly effective compared with FP plus salmeterol in separate inhalers in children under 12 and also resulted in annual cost savings of between £47 and £77. A number of other comparisons were also made and the results are available as electronic supplementary data. Conclusions: This is the first analysis to estimate the cost-effectiveness of SFC in chronic asthma compared with multiple comparators and based on a systematic identification of relevant trials and data on %SF