The ILLUMINATE trial involved 1,124 patients with moderate-to-severe SLE who received standard care plus either placebo or the human IgG4 antibody tabalumab, which targets B-cell activating factor (BAFF). This trial met its primary end point—a significant difference versus placebo in the proportion of patients achieving an SLE Responder Index 5 (SRI-5) response at week 52—in the group receiving 120 mg subcutaneous tabalumab every 2 weeks (38.4% versus 27.7%; P = 0.002), although not in those receiving once-monthly dosing.