The addition of ustekinumab, an IL-12 and IL-23 inhibitor, to standard-of-care treatment was more efficacious than placebo in the treatment of patients with active systemic lupus erythematosus (SLE) in a double-blind phase II randomized controlled trial. More patients in the ustekinumab group achieved an SLE responder index-4 (SRI-4) response at week 24 than in the placebo group (37 (62%) versus 14 (33%); P = 0.006). The safety profile of ustekinumab was consistent with that reported in previous trials of ustekinumab for other diseases.