A Study to Evaluate the Efficacy and Safety of CEP-33457 in Participants With Systemic Lupus Erythematosus (SLE)

The primary objective of this study is to evaluate the efficacy of a 200 micrograms (mcg) dose of CEP-33457 compared with placebo in participants with active systemic lupus erythematosus (SLE) as assessed by the proportion of participants achieving a combined clinical response using the SLE responder index (SRI) at Week 24.

The study consisted of a 2-week screening period (visit 1), a 20-week treatment period beginning with a baseline visit in which randomization was completed and study drug treatment began (visits 2 through 7), and a final assessment was performed 4 weeks after the last dose of study drug (visit 8 \[week 24 or early termination\]). Participants were randomized to receive either CEP-33457 or placebo subcutaneously (SC) every 4 weeks. Plasma samples for measurement of study drug concentration were collected in a subset of participants and study drug was administered at each study visit until the final visit. The dose of background steroid medication may have been increased, if needed, to treat the participant for minor fluctuations in lupus disease activity. One interim analysis was conducted when at least 80 participants completed Week 12 or had been withdrawn from the study. Participants who completed the treatment period returned to the study center 4 weeks after the last dose had been administered for final procedures and assessments. Final procedures and assessments for participants who withdrew from the study before 20 weeks of treatment were performed at the last visit. Final procedures and assessments for participants who participated in the study beyond week 24 were to be performed at the next regularly scheduled visit. Participants who complete the study will be eligible for participation in the 12-month open-label study (study C33457/3075; herein referred to as study 3075) to assess continued effectiveness and safety of the CEP-33457 treatment.