OBJECTIVES: The efficacy and safety of sifalimumab were assessed in a phase IIb, 
randomised, double-blind, placebo-controlled study (NCT01283139) of adults with 
moderate to severe active systemic lupus erythematosus (SLE).
METHODS: 431 patients were randomised and received monthly intravenous 
sifalimumab (200 mg, 600 mg or 1200 mg) or placebo in addition to 
standard-of-care medications. Patients were stratified by disease activity, 
interferon gene-signature test (high vs low based on the expression of four 
genes) and geographical region. The primary efficacy end point was the 
percentage of patients achieving an SLE responder index response at week 52.
RESULTS: Compared with placebo, a greater percentage of patients who received 
sifalimumab (all dosages) met the primary end point (placebo: 45.4%; 200 mg: 
58.3%; 600 mg: 56.5%; 1200 mg 59.8%). Other improvements were seen in Cutaneous 
Lupus Erythematosus Disease Area and Severity Index score (200 mg and 1200 mg 
monthly), Physician's Global Assessment (600 mg and 1200 mg monthly), British 
Isles Lupus Assessment Group-based Composite Lupus Assessment (1200 mg monthly), 
4-point reductions in the SLE Disease Activity Index-2000 score and reductions 
in counts of swollen joints and tender joints. Serious adverse events occurred 
in 17.6% of patients on placebo and 18.3% of patients on sifalimumab. Herpes 
zoster infections were more frequent with sifalimumab treatment.
CONCLUSIONS: Sifalimumab is a promising treatment for adults with SLE. 
Improvement was consistent across various clinical end points, including global 
and organ-specific measures of disease activity.
TRIAL REGISTRATION NUMBER: NCT01283139; Results.