Baseline patient characteristics
| Characteristic | Placebo | Belimumab 10 mg/kg |
| mITT population | (n=226) | (n=451) |
| Country, n (%) | ||
| China | 171 (75.7) | 346 (76.7) |
| Korea | 34 (15.0) | 66 (14.6) |
| Japan | 21 (9.3) | 39 (8.6) |
| Female, n (%) | 210 (92.9) | 419 (92.9) |
| Age (years), mean (SD) | 31.7 (9.18) | 32.3 (9.65) |
| BMI (kg/m2), mean (SD) | 22.3 (4.04)* | 22.3 (3.42) |
| SLE disease duration (years), mean (SD) | 5.97 (5.19) | 6.07 (5.04) |
| BILAG organ domain involvement†, n (%) | ||
| At least 1A or 2B | 108 (47.8) | 204 (45.2) |
| At least 1A | 24 (10.6) | 40 (8.9) |
| At least 1B | 174 (77.0) | 361 (80.0) |
| No A or B | 46 (20.4) | 79 (17.5) |
| BILAG organ domain involvement (A or B), by category, n (%) | ||
| General | 12 (5.3) | 24 (5.3) |
| Mucocutaneous | 106 (46.9) | 225 (49.9) |
| Neurological | 1 (0.4)‡ | 0 |
| Musculoskeletal | 64 (28.3) | 119 (26.4) |
| Cardiovascular and respiratory | 2 (0.9) | 2 (0.4) |
| Vasculitis | 29 (12.8) | 59 (13.1) |
| Renal | 60 (26.5) | 109 (24.2) |
| Haematology | 50 (22.1) | 94 (20.8) |
| SELENA-SLEDAI category, n (%) | ||
| ≤9 | 102 (45.1) | 218 (48.3) |
| ≥10 | 124 (54.9) | 233 (51.7) |
| SELENA-SLEDAI score, mean (SD) | 10.2 (4.11) | 9.8 (3.83) |
| SFI*, n (%) | ||
| At least one flare | 28 (12.4) | 53 (11.8) |
| At least one severe flare | 10 (4.4) | 15 (3.3) |
| PGA category, n (%) | ||
| 0–1 | 8 (3.5) | 26 (5.8) |
| >1–2.5 | 209 (92.5) | 413 (91.6) |
| >2.5 | 8 (3.5) | 11 (2.4) |
| Missing | 1 (0.4) | 1 (0.2) |
| SDI score | ||
| Mean (SD) | 0.3 (0.61) | 0.2 (0.55) |
| Median (min, max) | 0.0 (0, 4) | 0.0 (0, 4) |
| Allowable SLE concomitant medications, n (%) | ||
| Steroids | 223 (98.7) | 443 (98.2) |
| Antimalarials | 157 (69.5) | 320 (71.0) |
| Other immunosuppressive/immunomodulatory agents | 146 (64.6) | 292 (64.7) |
| Azathioprine | 15 (6.6) | 48 (10.6) |
| Leflunomide | 19 (8.4) | 46 (10.2) |
| Methotrexate/methotrexate sodium | 15 (6.6) | 29 (6.4) |
| Mycophenolic acid/mycophenolate mofetil | 75 (33.2) | 130 (28.8) |
| Traditional Chinese medicine—glycosides of paeony/tripterygium | 31 (13.7) | 59 (13.1) |