ADALIMUMAB CLINICAL EFFICACY IS ASSOCIATED WITH RHEUMATOID FACTOR AND ANTI-CYCLIC CITRULLINATED PEPTIDE ANTIBODY TITRE REDUCTION: A 6-MONTH PROSPECTIVE STUDY

Background: Rheumatoid arthritis (RA), along with the clinical features of the disease, reveals serological abnormalities such as the presence of rheumatoid factor (RF) and, more recently, of anti-cyclic citrullinated peptide (CCP)antibodies. The latter have shown to be a useful diagnostic tools particularly in the early stages of the disease and to be predictive of the disease progression and radiological damage. Treatment of RA patients with anti-tumor necrosis factor (TNF-α) biologic agents has been associated with the reduction of specific autoantibodies such as RF and anti-CCP.Objectives: To investigate whether clinical efficacy of adalimumab treatment correlates with anti-CCP and RF titre decrease.Methods: 57 patients with refractory RA were treated with single self-injections of adalimumab subcutaneously at 40 mg every other week, in combination with methotrexate (MTX). At baseline and week 30, serum samples were tested for IgM-RF by two agglutination assays. Anti-CCP antibodies were tested using a new, second generation, commercially available ELISA kit (Menarini, Florence, Italy). Percentage change in C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) was calculated.Results: At baseline, 44 of the 57 patients with RA (77%) were positive for anti-CCP antibodies, and 38 of 57 (66%) were positive for RF. A strong correlation between anti-CCP antibodies and RF at baseline was observed(p<0.001).Though no patients who were positive for anti-CCP or RF at baseline became negative following the anti-TNF-alpha treatment, the serum titre of anti-CCP antibodies and RF decreased significantly after 6 months of treatment [anti-CCP (IU) (95.7 to 82.4, p<0.01); RF (IU) (121 to 81; p<0.001)]. When we grouped the patients on the basis of their clinical response to adalimumab, a significant decrease in serum levels of anti-CCP antibodies and RF was observed only in those who were clinically improved according to ACR 20 and ACR 50 criteria.Conclusion: Our results show that adalimumab treatment in RA induces a decrease in the serum titres of RF and anti-CCP antibodies in patients showing clinical improvement, suggesting that these measurements may be a useful adjunct in assessing treatment efficacy.Citation: Ann Rheum Dis, volume 64, supplement III, year 2005, page 454Session: Rheumatoid Arthritis – Treatment