Objective: The role of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP) in the response to treatment for rheumatoid arthritis (RA) such as tocilizumab (TCZ) is still not completely understood. This study investigates the relationship between the presence and levels of RF and anti-CCP and clinical response to TCZ in patients with RA.
Methods: This was an observational longitudinal study in 27 patients with active, long-standing RA despite previous treatment with >2 Disease-Modifying Anti Rheumatic Drugs (DMARDs) and/or steroids. Patients were treated with TCZ 8 mg/kg every 4 weeks. The following parameters were assessed: Erythro Sedimentation Rate (ESR), C - reactive protein (CRP), Health Assessment Questionnaire (HAQ), Disease Activity Score of 28 joints (DAS28), Clinical Disease Activity Index (CDAI) and Simplified Disease Activity Index (SDAI). IgM-, IgA- and IgGRFs and anti-CCP antibodies were measured using ELISA at baseline, 3 months (T1), 6 months (T2), and 12 months (T3).
Results: All patients showed significant and sustained clinical response to TCZ treatment. All clinical scales with the exception of HAQ significantly decreased. There was a significant correlation (p=0.03) between anti-CCP and SDAI changes from baseline at T1 and T2. However, no significant correlation was measured between antibody count at T0 and changes in the DAS-28 ESR at T1 and at T2. Also, there was no correlation between clinical scales and antibody levels RF-IgG, IgA, IgM as well as between clinical scales and anti-CCP levels.
Conclusions: Tocilizumab is effective in treating the clinical symptoms of RA, and the efficacy of this molecule was not correlated with either RF or anti-CCP levels.