Efficacy and Safety Study of Sirukumab in Patients With Giant Cell Arteritis

Study Summary

Sirukumab is a fully human anti-interleukin-6 (IL-6) immunoglobulin G1-kappa with a high affinity and specificity for binding to the human IL-6 molecule that may have therapeutic benefit in the treatment of giant cell arteritis (GCA) by interruption of multiple pathogenic pathways. Sirukumab inhibits IL-6-mediated signal transducer and activator of transcription 3 (STAT3) phosphorylation, resulting in the inhibition of the biological effect of IL-6. This study will evaluate the efficacy and safety of sirukumab to characterize the benefit-to-risk profile of sirukumab in the treatment of active GCA. The study will be conducted in 2 distinct parts (Part A and Part B) and consists of the following phases: Screening phase, Part A: 52-week double-blind treatment phase, Part B: 104-week extension phase with the option to receive open-label sirukumab based on disease status and a 16-week follow-up phase if applicable. Approximately 204 subjects with a diagnosis of GCA and active disease within 6 weeks of baseline will be randomized into Part A, the 52-week double-blind treatment phase, to receive one of two doses of sirukumab or placebo, each in addition to a pre-specified prednisone taper. The efficacy and safety of sirukumab in sustaining remission will be assessed at Week 52. Subjects completing Part A of the study will be eligible to enter Part B, the 104-week extension phase, designed to investigate the long-term maintenance of remission and safety following cessation of sirukumab treatment and to assess long-term corticosteroid use. Subjects with active GCA at the end of Part A or those with new onset of GCA flare during the first 52 weeks of Part B will be eligible to receive open-label sirukumab. Subjects will need to have follow-up safety evaluations for at least 16 weeks after receiving the last dose of study drug, applicable only for those who are withdrawn prematurely from the study or whose open-label sirukumab treatment in Part B completes after Week 88.

Primary Outcome

Sustained remission was defined as having achieved all of the following: 1) remission at Week 12, 2) absence of disease flare Week 12 through Week 52, 3) completion of the assigned prednisone taper, and 4) no requirement for rescue therapy through Week 52. Remission was defined as absence of clinical signs and symptoms of GCA and normalization of erythrocyte sedimentation rate (ESR) \[\<30 millimeters per hour\] and C-reactive Protein (CRP) \[\<1 milligram/deciliter\]) and flare was defined as r

Interventions

• DRUG Prednisone
• DRUG Sirukumab
• DRUG Placebo to match sirukumab
• DRUG Placebo to match prednisone