Background:The shared epitope (SE) is a significant genetic risk factor for rheumatoid arthritis (RA), and it has been proposed to be associated with T-cell activation and the production of anti-citrullinated protein antibody (ACPA).1-3The results from the Early AMPLE trial, a head-to-head trial comparing the efficacy of abatacept versus adalimumab among early moderate-to-severe RA patients with positive ACPA (ACPA+) and rheumatoid factor (RF), showed that at week 24, patients with SE positivity (SE+) responded better to abatacept compared to adalimumab across all efficacy measures evaluated (ACR20 [American College of Rheumatology], ACR50, ACR70, DAS[disease activity score]28-CRP[C-reactive protein]).4Objectives:To compare the cost per responder (CPR) between abatacept and adalimumab among RA patients with SE+ at week 24 using the Early AMPLE trial data from a United States (US) payer perspective.Methods:A CPR analysis was conducted for RA patients with SE+, ACPA+, and RF. Responders were defined as patients achieving ACR20, ACR50, ACR70, or DAS28-CRP ≤2.6 and efficacy data was sourced from the trial (Figure 1).4Approved product labels were referenced for treatment dosing regimen and wholesale acquisition cost was used to calculate pharmacy cost.5A real-world rebate scenario was considered for adalimumab (30%) to reflect the real-world pricing in the US market. The CPR was calculated as the total pharmacy cost divided by the proportion of responders.Results:The total pharmacy cost at week 24 was $26,273 per patient for abatacept and $21,731 per patient for adalimumab. With achieving ACR70 as the definition of responder, the CPR at 24-week was $46,337 for abatacept and $74,935 for adalimumab, a difference of $28,598 (Table 1). The CPR was consistently lower for abatacept compared to adalimumab across all clinical measures, with difference ranging from $7,099 to $43,609.Table 1.Overall cost per responder resultsAbataceptAdalimumabDifferenceACR20$30,303.74$37,403.06-$7,099.32ACR50$34,254.68$48,077.83-$13,823.15ACR70$46,337.46$74,935.10-$28,597.64DAS28-CRP ≤2.6$52,546.68$96,155.65-$43,608.97Conclusion:While the pharmacy cost was higher for abatacept compared to adalimumab driven by the rebate, due to its higher clinical efficacy, the CPR was consistently lower for SE+ RA patients treated with abatacept. The results may be useful for US healthcare decision makers in understanding how to optimize treatment for SE+ RA patient while minimizing costs in today’s budget constrained environment.References:[1]Gregersen PK, Silver J, Winchester RJ. The shared epitope hypothesis. An approach to understanding the molecular genetics of susceptibility to rheumatoid arthritis.Arthritis and rheumatism. 1987;30(11):1205-13.[2]Holoshitz J. The rheumatoid arthritis HLA-DRB1 shared epitope.Curr Opin Rheumatol. 2010;22(3):293-8.[3]Sakkas LI, Bogdanos DP, Katsiari C, et al. Anti-citrullinated peptides as autoantigens in rheumatoid arthritis-relevance to treatment.Autoimmun Rev. 2014;13(11):1114-20.[4]Fleischmann R, Weinblatt M, Ahmad H, et al. Efficacy of abatacept and adalimumab in patientsn with early rheumatoid arthritis with multiple poor prognostic factors: post hoc analysis of a randomized controlled clinical trial (AMPLE).Rheumatol Ther. 2019;6(4): 559-571.[5]Truven Health Analytics. Redbook online. Accessed October 11, 2019.Disclosure of Interests:Sang Hee Park Consultant of: Pharmerit International, which received consultancy fees from Bristol-Myers Squibb (US), Inc. for this study, Xue Han Employee of: BMS, Francis Lobo Shareholder of: Bristol-Myers Squibb (US), Employee of: Bristol-Myers Squibb (US), Sakina Nanji Consultant of: Pharmerit International, which received consultancy fees from Bristol-Myers Squibb (US), Inc. for this study, Dipen Patel Consultant of: Pharmerit International, which received consultancy fees from Bristol-Myers Squibb (US), Inc. for this study
Distinct ACPA fine-specificities, formed under the influence of HLA shared epitope alleles, have no effect on radiographic joint damage in rheumatoid arthritis
