| Days 1–197 | Days 1–365 | ||||
| Abatacept + MTX (n = 156) | Placebo + MTX (n = 110) | Infliximab + MTX (n = 165) | Abatacept + MTX (n = 156) | Infliximab + MTX (n = 165) | |
| n (%)* | n (%)* | n (%)* | n (%)* | n (%)* | |
| Deaths | 1 (0.6) | 0 | 1 (0.6) | 1 (0.6) | 2 (1.2) |
| SAEs | 8 (5.1) | 13 (11.8) | 19 (11.5) | 15 (9.6) | 30 (18.2) |
| Related SAEs | 3 (1.9) | 3 (2.7) | 8 (4.8) | 5 (3.2) | 14 (8.5) |
| Discontinuations due to SAEs | 2 (1.3) | 0 | 4 (2.4) | 4 (2.6) | 6 (3.6) |
| AEs | 129 (82.7) | 92 (83.6) | 140 (84.8) | 139 (89.1) | 154 (93.3) |
| Related AEs | 64 (41.0) | 46 (41.8) | 74 (44.8) | 72 (46.2) | 96 (58.2) |
| Discontinuations due to AEs | 3 (1.9) | 1 (0.9) | 8 (4.8) | 5 (3.2) | 12 (7.3) |
| Serious infections | 2 (1.3) | 3 (2.7) | 7 (4.2) | 3 (1.9) | 14 (8.5) |
| Autoimmune symptoms and disorders | 1 (0.6) | 1 (0.9) | 1 (0.6) | 2 (1.3) | 1 (0.6) |
| Malignant neoplasms | 1 (0.6) | 1 (0.9) | 2 (1.2) | 1 (0.6) | 2 (1.2) |
*More than one AE or SAE could be reported in each patient; percentages represent the proportion of patients who reported ⩾1 event.
AE, adverse event; MTX, methotrexate; SAE, serious adverse event.