CP-084 Interleukin-6–174G>C genetic polymorphism (RS1800795) and the influence of clinical variables on the response to TOCILIZUMAB

BackgroundInterleukin 6(IL-6) is involved in the pathogenesis of rheumatoid arthritis via its broad effects on immune and inflammatory responses. Sustained IL-6 activity can cause tissue damage in different tissues. Previous studies have shown that G allele at the IL-6-174G>C (rs1800795) polymorphism is related to high producing IL-6. Other clinical variables such as being treated with methotrexate or DAS28 at baseline have been associated with interindividual differences in the response to tocilizumab.PurposeThe aim of this study was to evaluate the influence of the IL-6-174G>C (rs1800795) polymorphism and other clinical variables on the response to tocilizumab at 3 months after the first dose of the drug.Material and methodsThe IL-6-174G>C polymorphism was genotyped using predesigned TaqMan genotyping assay technology and analysed on a ViiA7 real time PCR system. Clinical response was evaluated at 3 months after the first dose of the drug using the 28 joint disease activity score criteria (DAS28). Patients were classified as ‘responders’ (good or moderate response according to EULAR criteria) or ‘non-responders’ (poor response according to EULAR criteria). EULAR good response is defined as a change in DAS28 >1.2 and DAS28 ≤3.2; EULAR moderate response is defined as a change in DAS28 of 0.6–1.2 and DAS28 ≤5.1, or a change of DAS28 >1.2 and DAS28 >3.2.ResultsClinical data from 127 patients were obtained; from all the variables included, we found statistical significance (pC (rs1800795) polymorphism as a genetic marker of clinical response to tocilizumab at 3 months. Our results showed that of all the variables studied, only concomitant treatment with methotrexate influ