Impact of anti-citrullinated protein antibody on tumor necrosis factor inhibitor or abatacept response in patients with rheumatoid arthritis

Abstract

Objective: To assess the impact of anti-citrullinated protein antibody (ACPA) serostatus on response totreatment with either tumor necrosis factor inhibitors (TNFi) or abatacept in patients with rheumatoidarthritis (RA).Methods: Data was obtained from the Optimizing Patient outcomes in Australian RheumatoLogy(OPAL) dataset. Patient data were included in the analysis if they commenced treatment with abatacept or TNFi between 01 August 2006 and 30 June 2017 and had at least 12 months’ follow-up. Theprimary outcome was the mean change in the clinical disease activity index (CDAI) score from baselineto 12 months.Results: A total of 2,052 patients were included of which 1,415 were in the TNFi cohort (n=1,053 ACPApositive) and 637 in the abatacept cohort (n=445 ACPA positive). Patients were predominantly female(75% TNFi; 80% abatacept) with no significant difference in age between cohorts. Patients with ACPApositivity had longer disease duration before commencing treatment in both the TNFi and abataceptcohorts compared to ACPA negative patients. No difference in disease severity was observed in thosewith ACPA negativity compared to those with ACPA positivity. Patients treated with TNFi and abatacept had significantly improved mean change in CDAI after 12 months; ACPA positivity was associatedwith greater response to treatment with abatacept compared to that in patients with ACPA negativity(p=0.011). No difference in response was observed based on ACPA serostatus in patients treated withTNFi (p=0.73).Conclusion: Baseline ACPA positivity was associated with improved clinical response using CDAI outcome measure at 12 months for abatacept but not for TNFi therapies.