Background: Anti-citrullinated protein antibodies (anti-CCP) has been found to be associated with not only the development of rheumatoid arthritis (RA), but also treatment response of RA. A recent study revealed that biologics targeting adaptive immunity, such as abatacept and rituximab, significantly decreased anti-CCP levels.[¹ However, anti-cytokine therapy, such as tumour necrosis factor inhibitor (TNFi), and methotrexate (MTX) did not significantly lower anti-CCP levels. However, whether concomitant use of sulfasalazine (SSZ) is associated with a decrease of anti-CCP levels in RA patients treated with TNFi or abatacept is unknown.

Objectives: To investigate the influence of sulfasalazine on the decrease of anti-CCP IgG levels among RA patients treated with TNFi or abatacept.

Methods: After exclusion of those whose baseline anti-CCP levels (CCP0) were above the level that could be accurately measured, we enrolled biologic-naïve, anti-CCP-positive RA patients who initiated treatment with TNFi (n=76), including etanercept (n=20), adalimumab (n=40), and golimumab (n=16), or abatacept (n=23). We followed anti-CCP levels (CCP1) 12 months after the initiation of biologics. A decrease of anti-CCP levels after therapy was identified if CCP1 minus CCP0 was less than 0. A multivariable logistic regression analysis was used to examine the influence of age, sex, biologic agents, disease duration, MTX, SSZ, hydroxychloroquine (HCQ), and leflunomide (LEF) on the risk of anti-CCP decrease, as shown by odds ratios (ORs) with 95% confidence intervals (CIs).

Results: Sixty-one (80.3%) of the 76 TNFi users and 18 of the 23 abatacept users were female (p=0.834). The mean ±SD age was 49.8±15.2 years and 56.0±12.4 years for TNFi users and abatacept users respectively (p=0.079). The mean ±SD disease duration was not different between TNFi users and abatacept users (4.7±5.1 vs. 6.7±4.9, p=0.098). Thirty-eight (50.0%) of 76 TNFi users and 7 (30.4%) of 23 abatacept users concomitantly used SSZ (p=0.099). Of the 74 TNFi users and 23 abatacept users, 59 (77.6%) and 14 (60.9%) had a decrease of anti-CCP levels (p=0.110). Using multivariable logistic regression analysis to examine factors associated with a decrease of the anti-CCP level after 12 months, we found that only concomitant use of SSZ had a significant correlation (OR, 3.54; 95% CI, 1.06–11.89; p=0.041). In subgroup analysis, this positive correlation remained consistently significant in the TNFi group (OR, 5.19; 95% CI, 1.16–23.29; p=0.031), but not in the abatacept group.

Conclusions: In RA patients who initiated treatment with TNFi or abatacept, concomitant use of SSZ was associated with a decrease of anti-CCP levels, especially among TNFi users.

Reference:

1. Wunderlich C, Oliviera I, Figueiredo CP, Rech J, Schett G (2017) Effects of DMARDs on citrullinated peptide autoantibody levels in RA patients-A longitudinal analysis. Semin Arthritis Rheum 46: 709–714.

Acknowledgements:

Disclosure of Interest: None declared

DOI: 10.1136/annrheumdis-2018-eular.1695