Table 2. 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