AB1204 COST-EFFECTIVENESS OF ABATACEPT IN SPAIN IN SEROPOSITIVE BIOLOGIC-NAÏVE EARLY RHEUMATOID ARTHRITIS PATIENTS WITH SHARED EPITOPE

Abstract

Background:The HLA class II Shared Epitope (SE) is a known Rheumatoid Arthritis (RA) risk allele linked to autoantibody production and disease progression. The recent Early AMPLE study suggests an enhanced treatment benefit of abatacept (ABA) over adalimumab (ADA) in SE positive patients with early seropositive RA.1Economic implications beyond the trial follow-up duration are unknown.Objectives:To estimate the cost-effectiveness of ABA vs ADA in biologic-naive RA patients seropositive for anti-citrullinated protein antibody and rheumatoid factor based on the Early AMPLE study.Methods:We developed a microsimulation model to estimate clinical response, medical cost, quality of life and survival from a Spanish payer perspective. The model captures the patient’s disease and treatment journey using response outcomes and the Health Assessment Questionnaire (HAQ) score. Patients who fail to respond switch to the next treatment line. Six treatment lines are included to capture a lifetime horizon. Responding patients (ACR50 and EULAR response) achieve an improvement in their HAQ score. Patient mortality was modelled as a function of HAQ. For both the overall Early AMPLE population and SE+ patients, incremental monthly cost per response over 2 years and incremental cost per QALY over a lifetime were estimated. Costs were based on local tariffs in Spain.Results:Baseline characteristics for the Early AMPLE (n=80) and the SE+ (n=61) patients were well balanced between the treatment groups.2Compared to ADA, the ABA cohort had a lower cost per response and the difference was more pronounced in the SE+ population, compared to the entire Early AMPLE population for both the response criteria (Table 1). Compared with ADA, the ABA cohort showed greater quality adjusted life years (QALYs) gains, and a modest increase in cost due to a prolonged time on treatment (Table 2). The incremental cost per QALY over a lifetime fell below commonly used thresholds in Spain (25-60 thousand Euros per QALY).3Table 1.Cost per response resultsFull Early AMPLEACR50EULARABAADAABAADACost per response (€) – 2 years25,86040,65426,99340,643Incremental monthly cost per response (€)-616-569SE positiveACR 50EULARABAADAABAADACost per response (€) – 2 years24,27240,24925,33741,425Incremental monthly cost per response (€)-666-670All incremental results are for ABA – ADATable 2.Cost-effectiveness results (discounted)Full Early AMPLEACR50EULARABAADAABAADALYs*30.1430.0630.1130.03QALYs8.327.817.577.12Time on treatment (years)4.172.035.143.06Costs (€)75,54768,15785,12280,933Incremental LYs*0.080.08Incremental QALYs0.520.45Incremental Costs (€)7,3904,189Incremental cost per QALY (€)14,3089,275SE positiveACR50EULARABAADAABAADALYs*30.3830.2230.1630.09QALYs8.207.597.406.90Time on treatment (years)4.482.025.383.02Costs (€)78,11368,65187,58681,321Incremental LYs*0.150.06Incremental QALYs0.610.50Incremental Costs (€)9,4626,265Incremental cost per QALY (€)15,41012,503*LY results are presented undiscounted. All incremental results are for ABA – ADAConclusion:Compared with ADA, ABA is a cost-effective alternative and is associated with a lower 2 years cost per response for both populations. The economic benefit and quality of life gain is greater in a SE+ patient population.