THU0725-HPR Cost effectiveness analysis of abatacept compared with tnf inhibitors in patients who are positive for anti-citrullinated protein antibodies based on results from an observational trial
Authors: S Johal, E Alemao
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Anti-citrullinated protein antibodies (ACPA) are highly specific to RA and patients (pts) who are ACPA positive (+) tend to develop more severe, erosive disease than ACPA-negative pts.<sup>1</sup> In an observational study exploring the status of ACPA on RA treatment response to abatacept (ABA) or a TNF inhibitor (TNFi), mean (SE) changes from baseline in CDAI at 6 months was –8.8 for ABA and –5.6 for TNFi initiators.<sup>2</sup> <h3>Objectives</h3> To evaluate the costs and benefits of treating pts with RA who are ACPA+ with ABA vs TNFi on background MTX. <h3>Methods</h3> An economic analysis was carried out estimating lifetime direct costs and quality-adjusted life years (QALYs) of ACPA+ pts with RA treated with ABA or TNFi from a UK National Health Service (NHS) perspective. QALYs are a measure of disease burden, adjusted to reflect quality of life lived. As data for the economic analysis were derived from a real-world study, an "average" pt was modelled, whose baseline characteristics were based on the observational study. CDAI changes at 6 months for each treatment were converted to HAQ changes, and disease progression was based on HAQ score changes over a lifetime. Continuation of therapy was based on rates from the real-world study. Mean long-term survival on treatment with ABA or TNFi was derived from the literature.<sup>3</sup> In the base case, pts discontinuing ABA or TNFi moved to palliative care (MTX). Direct medical costs and quality of life scores were correlated to HAQ scores.<sup>3,4</sup> Costs included hospitalizations, joint replacements and treatment costs. Estimates of differences in costs and QALYs between ABA and TNFi initiators were used to calculate an incremental cost-effectiveness ratio (ICER; cost per QALY gained). The annual cost of TNFi was calculated as an average of TNFi drugs in the UK (£ 9113). For ABA, an average cost of five biologics was used (£ 9244) to reflect a realistic cost to NHS UK. A sensitivity analysis examined the effect of varying the input parameters of efficacy, cost and utilities on costs and outcomes. <h3>Results</h3> Based on an "average" pt from the observational study, the total estimated QALYs for ABA and TNFi initiators were 6.4 and 6.27, respectively. Total lifetime costs were £ 41,378 and £ 40,627, respectively. The lifetime cost for ABA initiators was higher than for TNFi initiators due to the higher proportion of pts continuing ABA after 6 months. ABA treatment resulted in lower hospitalization costs. The cost per QALY for ABA (vs TNFi) was £ 8667. An intervention with an ICER of less than £ 30,000 per QALY gained is generally considered to be cost effective in the UK. In a sensitivity analysis, in which the annual cost of TNFi was assumed to be the same as a biosimilar agent (£ 7829), the ICER increased to £ 25,660. <h3>Conclusions</h3> Based on real-world data, abatacept is a cost-effective alternative to TNFi in an ACPA+ pt with RA. The increased treatment costs of abatacept are offset by the gain in benefits (QALYs) from higher CDAI reductions with abatacept. <h3>References</h3> van der Helm-van Mil AHM, et al. Arthritis Res Ther 2005;7:R949–58. Harrold LR, et al. Ann Rheum Dis 2016;75(Suppl 2):505–6. Malottki K, et al. Health Technol Assess 2011;15:1–278. Stevenson MD, et al. Health Technol Assess 2016;20:1–610. <h3>Disclosure of Interest</h3> S. Johal Consultant for: PAREXEL Access Consulting received a Consultancy fee to support the analysis, Employee of: HERON Commercialization, E. Alemao Shareholder of: Bristol-Myers Squibb, Employee of: Bristol-Myers Squibb