Background 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.1 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.2
Objectives To evaluate the costs and benefits of treating pts with RA who are ACPA+ with ABA vs TNFi on background MTX.
Methods 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.3 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.3,4 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.
Results 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.
Conclusions 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.
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Disclosure of Interest 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