Extended report Safety was assessed at each visit. Summary statistics were tabulated by treatment group at days 197 and 365. RESULTS Baseline demographics and clinical characteristics A total of 431 patients were randomised and treated with abatacept (n = 156), placebo (n = 110) or infliximab (n = 165) (fig 1). Baseline demographics and clinical characteristics were similar between groups (table 1). At randomisation, patients had active disease despite background MTX (mean DAS28 (ESR) of 6.8–6.9, tender joint counts 30.3–31.7, swollen joint counts 20.1–21.3 and mean HAQ-DI of 1.7–1.8). The mean dose of MTX was 16.3–16.6 mg and mean treatment duration was 18.3–23.7 months. Use of additional medications Concomitant medications and NSAIDs were used by a similar proportion of patients across treatment groups at randomisa- tion (table 1). Between days 198–365, when the protocol permitted adjustments to background medications, 12.8% and 17.6% of abatacept and infliximab-treated patients, respectively, added a DMARD, or increased their dose of MTX/corticoster- oids from baseline. Figure 1 Patient disposition over 1 year. The ATTEST trial was a 12-month global trial conducted at 86 sites in the US (20 sites), Europe (18 sites (5 in Poland, 4 in Spain, 4 in Sweden, 2 in Russia, 2 in Denmark and 1 in Switzerland)), Canada (11 sites), Australia (6 sites), Mexico (10 sites), Argentina (5 sites), Brazil (8 sites), Peru (5 sites) and South Africa (3 sites). Patients were randomised in a 3:3:2 ratio to 6 months of abatacept (approximating 10 mg/kg), infliximab (3 mg/kg), or placebo treatment. During days 198–365, efficacy and safety data are not presented for the placebo group following reallocation to abatacept. 1098 Ann Rheum Dis 2008;67:1096–1103. doi:10.1136/ard.2007.080002