AB0249 EFFECT OF RF AND ACPA NEGATIVATION IN CLINICAL RESPONSE IN RA PATIENTS UNDER BIOLOGIC THERAPY

Background Both rheumatoid factor (RF) and antibodies against cyclic citrullinated peptide (ACPA) are regarded as serological markers of Rheumatoid Arthritis (RA), being well recognized as diagnostic and prognostic tools. However, their potential role in the disease’s monitoring and clinical response is still under debate. Objectives To assess the effect of RF and ACPA negativation in clinical response to biologic therapy in RA patients. Methods Longitudinal retrospective study of RA patients treated with biologic therapy as first line option. Demographic and clinical data were collected at baseline and at 24 months follow-up, including: RF and ACPA status (negative or positive), ESR, CRP, DAS28 4v ESR, CDAI, SDAI, HAQ, EULAR and ACR response. RF was considered positive if ≥ 30 U/ml and ACPA if ≥ 7 U/ml. SPSS statistics 22.0 was used for statistical analysis. Results 169 patients were included with mean (±SD) age of 50.7 ± 10.6 years and median disease duration (min-max) of 10.2 (0.69-39.4) years. The majority were female (84%). At baseline 160 (94.7%) were positive for RF and 166 (98.2%) were positive for ACPA. 77 (45.6%) turned negative for RF and/or ACPA at a median time of 20.3 months after biologic therapy begining. 63 out of 169 patients become negative for RF (37.3%) and 17 patients for ACPA (10.1%). 52 (30.6%) patients were treated with etanercept, 39 (22.9%) adalimumab, 27 (15.9%) rituximab, 19 (11.2%) tocilizumab; 16 infliximab (9.4%); 14 (8.2%) golimumab; 1 (0.6%) certolizumab and 1 (0.6%) anakinra. The mechanism of action of the drug didn’t differ between patients who became seronegative for RF and/or ACPA and those who remained seropositive (70.2% under anti-TNFα agents vs 73.9% for the other biologics). Most of the patients in the first group began adalimumab (32.5%) and most of the patients in the latter began etanercept (34.8%). Demographic characteristics like age, sex, disease duration, and extraarticular manifestations were comparable in both groups. They weren’t comparable in terms of smoking habits (p=0.014): just 3 (3.9%) current smokers in those who became negative for RF and/or ACPA vs 17 (18.5%) among those who remained seropositive. Nevertheless, there weren’t statistically significant differences in ΔDAS28 4v ESR, ΔERS, ΔCRP, ΔCDAI, ΔSDAI, ΔHAQ, EULAR or ACR response at 24-months between patients with negativation of at least one antibody and those who remained seropositive. Conclusion In our sample, change of antibody status wasn’t predictor of better response to biologic therapy. Therefore the results did not support the association between the persistence of RF or ACPA and the lack of effectiveness of biologic therapy at 2 years of treatment, but further studies are needed. Reference [1] Alexandra B. et al. Prospective cohort study of effects of infliximab on rheumatoid factor, anti-cyclic citrullinated peptide antibodies and antinuclear antibodies in patients with long-standing rheumatoid arthritis; Joint Bone Spine 76 (2009) 248e253. Disclosure of Interests None declared