Summary of primary and major secondary efficacy endpoints, based on IBA assessment (mITT population,* N=263)
| Observed response rate, n (%) | BEL/RTX versus BEL/PBO | |||||
| Blinded BEL/PBO (n=72) | Blinded BEL/RTX (n=144) | Open-label BEL/ST reference arm†
(n=47) | Observed treatment difference (%) | OR (95% CI)‡ | P value‡ | |
| Primary endpoint | ||||||
| Disease control§ at week 52 | 12 (16.7) | 28 (19.4) | 12 (25.5) | 2.78 | 1.27 (0.60 to 2.71) | 0.5342 |
| Major secondary endpoints | ||||||
| Clinical remission§ at week 64 | 4 (5.6) | 9 (6.3) | 5 (10.6) | 0.69 | 1.12 (0.33 to 3.78) | 0.8582 |
| Disease control§ at week 104 | 5 (6.9) | 16 (11.1) | 10 (21.3) | 4.17 | 1.64 (0.57 to 4.72) | 0.3613 |
*mITT population excludes 29 patients from the BEL/ST group, due to independent blinded assessors being potentially unblinded.
†ST included corticosteroids, antimalarials, immunosuppressants and NSAIDs.
‡OR (95% CI), adjusted treatment difference (95% CI), and p value are from a logistic regression model with covariates: baseline SLEDAI-2K, baseline immunosuppressants, baseline prednisone-equivalent dose and treatment group.
§Disease control defined as SLEDAI-2K score ≤2 achieved without immunosuppressants and with a prednisone-equivalent dose of ≤5 mg/day; clinical remission defined as a clinical SLEDAI-2K score=0, without immunosuppressants and with corticosteroids at a prednisone-equivalent dose of 0 mg/day.
BEL, belimumab; IBA, independent blinded assessor; mITT, modified intention-to-treat; NSAIDs, non-steroidal anti-inflammatory drugs; PBO, placebo; RTX, rituximab; SLE, systemic lupus erythematosus; SLEDAI-2K, SLE Disease Activity Index-2000; ST, standard therapy.