AB0509 Comparative effectiveness of tocilizumab (TCZ) and rituximab (RTM) using different disease activity indices (DAS 28, SDAI and CDAI) in patients with rheumatoid arthritis (RA)

Background Humanized anti-interleukin-6 (IL-6) receptor monoclonal antibody (TCZ) and chimeric monoclonal antibody against CD 20 positive B cells (RTM) are effective and safe preparations for the treatment of RA. Taking into account the different mechanisms of action, time of coming effect, influence on a acute -phase reactants, it is interesting to compare the effectiveness of treatment TCZ and RTM using different composite disease activity indices (DAS 28, SDAI and CDAI) and the new criteria remission ACR/EULAR 2011. Methods The study included 76 RA patients (pts), divided into two groups. The first group included 42 pts with RA (32 women, mean age 50.5, 43-55, mean disease duration 56.5, 23-81 months). All pts received 6 intravenous TCZ infusions (8 mg/kg) every 4 weeks, in combination with DMARDs and glucocorticoids. The second group - 34 pts with RA (31 women, mean age 49, 42-64, mean disease duration 66, 36-132 months) received two intravenous infusions of RTM - 35% at a dose of 500 mg, 65% of the dose of 1000 mg every two weeks in combination with DMARDs and glucocorticoids. 38% of the patients of the second group received previous biologic therapy. Erythrocyte sedimentation rate – ESR (mm/hr) (Westergren method); serum concentrations of CRP (mg/L), IgM RF (IU/ml) (laser nephelometry); antibodies to cyclic citrullinated peptide – anti-CCP2 (U/ml) (electrochemiluminiscent assay) Results First group: baseline meanings [Me (interquartile range)] DAS 28 were (5,87-7,04), SDAI 45,0 (36,2-57,0) and CDAI 41,5 (32,0-53,0). On the 24-th week: DAS 28 2,11 (1,29-2,77), SDAI 4,4 (2,0-8,8) and CDAI 3,6 (1,4-7,6). Second group: baseline meanings [Me (interquartile range)] DAS28 were (5,52-6,81), SDAI 34,3 (23,8-45,9) and CDAI 31,3 (21,8 - 38.5). On the 24-th week: DAS 28 3,53 (2,61-4,00), SDAI 7,5 (4,9-11,7) and CDAI 5,5 (3,5-9,5). In the first and the second group pts on the 24-th week of therapy remission was achieved on DAS 28 in 71% and 23.5%, SDAI in 31% and 14.7%, CDAI in 33% and 17.6% respectively. Low disease activity - DAS 28 12% in the group TCZ and 20.5% in the group of RTM, the SDAI- 50% and 55.8%, CDAI- 47.6% and 58.8%. Among biologic-naïve pts second group DAS 28/SDAI/CDAI remission achieved more frequently (38%/23.8%/28.6%) than pts who received prior biologic therapy (0) and was comparable to frequency of remission in pts of the first group (the indices SDAI and CDAI).The remission on new criteria of ACR/EULAR 2011 the first group pts was 24%, sec