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Economic evaluation of etanercept in the management of chronic plaque psoriasis |
Lloyd A, Reeves P, Conway P, Reynolds A, Baxter G |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. CRD summary This study examined the cost-effectiveness of etanercept 50mg twice weekly in adults with moderate to severe plaque psoriasis, who were unable to take standard systemic therapies. The authors concluded that etanercept 50mg was cost-effective from the perspective of the UK National Health Service, especially in patients with severe disease or poor quality of life at baseline. The study was well conducted and clearly presented, especially for the economic data. The authors’ conclusions appear to be valid. Type of economic evaluation Study objective This study examined the cost-effectiveness of etanercept 50mg twice weekly (biw) in adults with moderate to severe plaque psoriasis who were unable to take standard systemic therapies. Interventions The regimen of 12 weeks of etanercept 50mg biw was compared with no systemic therapy, and with 12 weeks of etanercept 25mg biw. Patients who responded to therapy were assumed to continue on etanercept 25mg biw intermittently. Methods Analytical approach:The economic analysis was based on a decision analytic model with a 10-year time horizon. The authors stated that the analysis was carried out from the perspective of the UK National Health Service (NHS).
Effectiveness data:The clinical data came from three published randomised controlled trials (RCTs). The authors stated that these three RCTs were similar enough to allow pooling of patient level data. Overall, 1,187 patients were randomised to a licensed dose of etanercept and 671 were selected for this analysis. These were patients with a Psoriasis Area and Severity Index (PASI) and a Dermatology Life Quality Index (DLQI) of 10 or more at baseline. No other details on the methods of these studies were reported. The primary endpoint was the treatment efficacy, which was a reduction in PASI of 75% or more.
Monetary benefit and utility valuations:The utility valuations were derived from patients in the three RCTs, who completed the DLQI questionnaires at baseline and after 12 weeks of treatment. These DLQI values were transformed into utility scores using a formula determined by a regression analysis, as shown in a previous study.
Measure of benefit:Quality-adjusted life-years (QALYs) were the summary benefit measure and were discounted at an annual rate of 3.5%.
Cost data:The economic analysis considered the costs of the study drugs, visits, and treatment of adverse events (including hospitalisations). The costs of topical medications were not included as there was no evidence of a difference between groups. The unit costs and quantities of resources used were presented separately. Resource use was mainly derived from the pooled database of the three RCTs and another published study. The unit costs came from the British National Formulary and the Department of Health. These were in UK pounds sterling (£) and the price year was 2006. Future costs were discounted at an annual rate of 3.5%.
Analysis of uncertainty:The issue of uncertainty was investigated using various approaches. Sub-groups were considered to explore the impact of different levels of disease severity and the use of individual rather than pooled studies. A deterministic analysis considered variations in specific model inputs. A stochastic sensitivity analysis used bootstrap re-sampling to generate 95% confidence intervals (CIs) around the costs and benefits. Results In the base case, for patients with a PASI and a DLQI of 10 or more at baseline, the 10-year costs were £47,587 with etanercept 50mg, £44,855 with 25mg, and £41,985 with no systemic therapy. The QALYs were 1.61 with 50mg, 1.37 with 25mg, and 0.70 with no therapy. Thus, the incremental cost per QALY was £6,217 (95% CI: 5,396 to 7,486) with 50mg over no therapy, £4,297 (95% CI: 3,671 to 5,231) with 25mg over no therapy, and £11,710 (95% CI: 8,407 to 26,642) with 50mg over 25mg.
The sensitivity analysis showed that these findings were sensitive to variations in the assumed requirement for hospitalisation in untreated individuals and in the response rate achieved in re-treatment. Other alternative assumptions did not substantially alter the base-case findings. The incremental cost per QALY for etanercept 50mg always remained lower than £15,000 compared with no therapy and £20,000 compared with etanercept 25mg.
The analysis identified a positive correlation between the incremental cost and incremental benefit, as successful treatment was associated with both higher benefits and increased management costs. Authors' conclusions The authors concluded that etanercept 50mg biw was cost-effective from the perspective of the UK NHS, especially in patients with severe disease or poor quality of life at baseline. CRD commentary Interventions:The authors justified their selection of the comparators. The 50mg biw dose was selected because a previous economic evaluation carried out by the National Institute of Health and Clinical Excellence (NICE) considered only the 25mg biw dose. The selection of no intervention was appropriate as the background comparator as this patient population had already received conventional systemic therapy.
Effectiveness/benefits:The use of three RCTs to derive efficacy data was appropriate as their design should ensure the validity and rigour of the clinical estimates. The authors stated that the trial samples were homogeneous with respect to their baseline characteristics, which enabled the pooling of data to provide a large sample of patients. The sensitivity analysis showed that the use of individual RCT data did not change the authors’ conclusions. Apart from the baseline characteristics of the patient groups, no information on the methods of the three trials was provided. The use of the DLQI was appropriate because such a tool was validated for assessment of health-related quality of life in psoriasis. QALYs are a valid measure, which not only capture the impact of the interventions on quality of life, but also allow cross-disease comparisons to be made.
Costs:The economic analysis was carried out satisfactorily. The cost categories were consistent with the perspective as were the sources of data, which reflected NHS official sources. Details on the unit costs, resource use, price year, and use of discounting were clearly reported, enhancing the transparency of the economic analysis. Key economic inputs were varied in the sensitivity analysis.
Analysis and results:The methods used to synthesise the costs and benefits and to investigate the issue of uncertainty were appropriate. The results of both the base case and the sensitivity analyses were clearly presented. The authors compared the results of their study with other published evidence, which showed similar findings. The authors briefly discussed some potential limitations of their analysis, mainly related to the short-term clinical evidence, and stated that there was a need for future long-term naturalistic studies on etanercept.
Concluding remarks:The study was well conducted and clearly presented, especially for the economic data. The authors’ conclusions appear to be valid. Bibliographic details Lloyd A, Reeves P, Conway P, Reynolds A, Baxter G. Economic evaluation of etanercept in the management of chronic plaque psoriasis. British Journal of Dermatology 2009; 160(2): 380-386 Other publications of related interest Woolacott N, Bravo Vergel Y, Hawkins N, et al. Etanercept and infliximab for the treatment of psoriatic arthritis: a systematic review and economic evaluation. Health Technol Assess 2006;10:1-239.
Papp KA, Tyring S, Lahfa M, et al. A global phase III randomized controlled trial of etanercept in psoriasis: safety, efficacy, and effect of dose reduction. Br J Dermatol 2005;152:1304-12.
Leonardi CL, Powers JL, Matheson RT, et al. Etanercept as monotherapy in patients with psoriasis. N Engl J Med 2003;349:2014-22. Indexing Status Subject indexing assigned by NLM MeSH Adult; Anti-Inflammatory Agents, Non-Steroidal /economics /therapeutic use; Chronic Disease; Cost-Benefit Analysis; Drug Administration Schedule; Etanercept; Female; Humans; Immunoglobulin G /economics /therapeutic use; Male; Middle Aged; Models, Economic; Patient Selection; Psoriasis /drug therapy; Randomized Controlled Trials as Topic; Receptors, Tumor Necrosis Factor /therapeutic use; Severity of Illness Index AccessionNumber 22009100633 Date bibliographic record published 09/09/2009 Date abstract record published 07/10/2009 |
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