Table 1 Baseline demographics and clinical characteristics Abatacept + MTX (n = 156) Placebo + MTX (n = 110) Infliximab + MTX (n = 165) Extended report Demographic/characteristic Age, years (SD) Gender, % female Race, % Caucasian Geographic origin: North America, n (%) South America, n (%) Europe, n (%) Rest of the world, n (%) Disease duration, years (SD) Tender joints, n (SD) Swollen joints, n (SD) Erythrocyte sedimentation rate, mm/h (SD) C-reactive protein levels, mg/dl (SD) DAS28 (ESR), n (SD) HAQ-DI, 0–3 (SD) Rheumatoid factor positive, n (%) Concomitant medications Total patients on concomitant medications, n (%) MTX, n (%) Dose, mg/week (SD) Duration, months (SD) Corticosteroids, n (%) NSAIDs, n (%) 49.0 (12.5) 83.3 80.8 16 (10.3) 93 (59.6) 39 (25.0) 8 (5.1) 7.9 (8.5) 31.6 (13.9) 21.3 (8.6) 49.4 (31.2) 3.1 (2.7) 6.9 (1.0) 1.8 (0.6) 136 (87.2) 156 (100) 156 (100) 16.5 (3.7) 18.3 (20.0) 118 (75.6) 133 (85.3) 49.4 (11.5) 87.3 76.4 10 (9.1) 66 (60.0) 29 (26.4) 5 (4.5) 8.4 (8.6) 30.3 (11.7) 20.1 (7.0) 47.0 (32.6) 2.7 (2.6) 6.8 (1.0) 1.8 (0.7) 85 (77.3) 110 (100) 110 (100) 16.6 (3.7) 23.7 (25.6) 77 (70.0) 93 (84.5) 49.1 (12.0) 82.4 80.6 15 (9.1) 96 (58.2) 39 (23.6) 15 (9.1) 7.3 (6.2) 31.7 (14.5) 20.3 (8.0) 47.8 (30.4) 3.3 (3.2) 6.8 (0.9) 1.7 (0.7) 140 (84.8) 165 (100) 164 (99.4) 16.3 (3.6) 23.6 (26.8) 118 (71.5) 142 (86.1) MTX, methotrexate; DAS28 (ESR), Disease Activity Score 28 (based on erythrocyte sedimentation rate levels); HAQ-DI, Health Assessment Questionnaire Disability Index; NSAID, non-steroidal anti-inflammatory drug. Discontinuations During the first 6 months, discontinuations occurred in 5.8, 2.7 and 7.9% of the abatacept, placebo and infliximab groups, respectively. Between days 198–365, 5.1 and 6.7%, of the abatacept and infliximab groups, respectively, discontinued. Discontinuation due to AEs and SAEs were highest in the infliximab group in both periods (fig 1). Similar numbers of patients from the abatacept and infliximab groups completed 1 year of treatment (fig 1). Clinical efficacy DAS28 At day 197, the reduction in DAS28 (ESR), was significantly greater with abatacept vs placebo (–2.53 vs –1.48, p,0.001; fig 2A). A greater proportion of patients also experienced a good EULAR response (20.0 vs 10.8%), LDAS (20.7 vs 10.8%) and were in DAS28 (ESR)-defined remission (11.3 vs 2.9%), for abatacept vs placebo, respectively (fig 2B). Reductions in DAS28 (ESR) were also significantly greater in the infliximab vs placebo groups at day 197 (–2.25 vs –1.48, p,0.001; fig 2A), with a higher proportion of patients experiencing a good EULAR response (22.9 vs 10.8%), LDAS (25.6 vs 10.8%) and were in DAS28 (ESR)-defined remission (12.8 vs 2.9%), respectively (fig 2B). At day 197, the relative efficacy of abatacept and infliximab as assessed by the DAS28 (ESR) was similar. At day 365, a greater reduction in DAS28 (ESR) was observed with abatacept than with infliximab (fig 2A; –2.88 vs –2.25; estimate of difference (95% CI) = –0.62 (–0.96, –0.29)). Also, the proportion of patients achieving a good EULAR response (32.0 vs 18.5%, estimate of difference (95% CI) = 13.5% (3.6, 23.3)), LDAS (35.3 vs 22.4%, estimate of difference (95% CI) = 12.9 (2.1, 23.7)), and DAS28 (ESR)-defined remission (18.7 vs 12.2%, estimate of difference (95% CI) = 18.7 (–2.2, 15.2)) were higher with abatacept compared with infliximab (fig 2B). Ann Rheum Dis 2008;67:1096–1103. doi:10.1136/ard.2007.080002 When disease activity was assessed using a sensitivity analysis (LOCF prior to increase in antirheumatic medications was performed), consistent improvements were demonstrated with abatacept: DAS28 (ESR) mean changes were significantly greater with abatacept vs infliximab at day 365 (–2.8 vs –2.2, respectively (difference from infliximab of –0.7, 95% CI of –1.0, –0.3)). American College of Rheumatology response rates At day 197, ACR 20, 50 and 70 responses were significantly greater with abatacept vs placebo (ACR 20: 66.7 vs 41.8%, p,0.001; ACR 50: 40.4 vs 20.0%, p,0.001; and ACR 70: 20.5 vs 9.1%, p = 0.019). ACR 20, 50 and 70 responses were also significantly higher in the infliximab group vs placebo (ACR 20: 59.4 vs 41.8%, p = 0.006; ACR 50: 37.0 vs 20.0%, p = 0.004; and ACR 70: 24.2 vs 9.1%, p = 0.002). The onset of response, as assessed by ACR 20 response rates, was generally more rapid for infliximab compared with abatacept (fig 3), however, by day 85, responses were similar (fig 3). Abatacept and infliximab demonstrated similar responses at day 197. During the second 6 months of the trial, the responses associated with abatacept were maintained, while those observed with infliximab were not. At day 365, ACR 20 responses were higher with abatacept than with infliximab (ACR 20: 72.4 vs 55.8%, difference of 16.7, 95% CI = 5.5, 27.8). In addition, the percentages of ACR 50 and 70 responders were numerically higher with abatacept vs infliximab treatment (with overlapping 95% CIs for the estimate of difference for ACR 50: 45.5 vs 36.4%, estimate of difference (95% CI) = 9.1 (–2.2, 20.5); ACR 70: 26.3 vs 20.6%, estimate of difference (95% CI) = 5.7 (–4.2, 15.6), respectively). Physical function At 6 months, significantly more patients in the abatacept group than in the placebo group demonstrated a clinically meaningful 1099