THU0364 Immunogenicity of anti-tnf drugs and clinical response in patients with spondyloarthritis

Background Antidrug antibodies (ADAb) seem to be associated with a loss of response in immune-mediated inflammatory diseases (1) and in psoriatic arthritis (2). Objectives To assess the effect of ADAb on clinical response in patients with spondyloarthritis (SpA) treated with anti-TNF drugs. Methods We conducted a systematic literature review of controlled trials and observational studies assessing the effect of ADAb on response to anti-TNF drugs (Adalimumab (ADL), Certolizumab (CTZ), Etanercept (ETA), Golimumab (GOL) and Infliximab (INF)) in patients with axial or peripheral SpA. Databases analysed were PubMed, the Cochrane library, and ACR/EULAR meeting abstracts, until January 2017. A meta-analysis was performed using the inverse variance approach and statistical heterogeneity was assessed with the Cochran Q-test and I 2 values. A statistical threshold of 5% was considered as significant. Results Over 1,387 publications screened, 7 studies were selected for meta-analysis (3–9). These studies were observational studies (n=6) or controlled trial (n=1); involved patients with axial or peripheral SpA (n=6) or psoriatic arthritis (n=1); included treatments with ADL (n=4), ETA (n=1), INF and INF biosimilar (n=2), or various anti-TNF drugs (n=1). ADAb rates varied between anti-TNF drugs: 0% for ETA, 13.6–31.4% for ADL, 0–28.9% for INF. Patients with ADAb were less often responders than patients without ADAb in 6 studies, more often responders in one study, while the risk ratio (RR) for response was not assessable in one study due to the absence of ADAb. The weighted pooled RR (95% CI) for response to anti-TNF drugs was 0.73 (0.54–0.98) in ADAb+ in comparison with ADAb- patients (p=0.04) (see figure). There were trends towards more infusion reactions and lower serum drug levels in patients with ADAb (data not shown). Conclusions According to the results of this meta-analysis, ADAb positivity is associated with a lower rate of response to anti-TNF agents in patients with SpA. References The immunogenicity of anti-TNF therapy in immune-mediated inflammatory diseases: a systematic review of the literature with a meta-analysis, Garces.S and al, ARD 2014; 72:1947–1955. The comparative immunogenicity of biologic therapy and it9s clinical releavance in psoriatic arthritis: a systematic review of the literature, Balsa.A and al, ACR 2016, Abstract number 1691. Disclosure of Interest None declared