A Study of Siltuximab (Anti- IL 6 Monoclonal Antibody) in Patients With High-risk Smoldering Multiple Myeloma

This is a randomized (treatment assigned by chance), double-blind (neither patient nor investigator know which treatment is given), multicenter study to evaluate the safety and efficacy of siltuximab compared with placebo in patients with high-risk SMM (defined as bone marrow plasma cells \>=10% and either serum monoclonal protein \>=3 g/dL, or abnormal free light chain ratio \<0.126 or \>8 and serum M-protein \<3 g/dL but \>=1 g/dL). Approximately 74 patients will receive either siltuximab or placebo by intravenous (IV, injection into a vein) infusion every 4 weeks until progression to symptomatic multiple myeloma, unacceptable toxicity, withdrawal of consent, or the end of the study (approximately 4 years after randomization of the last patient). Efficacy, pharmacokinetics, immunogenicity, and potential biomarkers will be assessed at time points defined in the protocol. Patient reported outcomes (European Organization for Research and Treatment of Cancer, Quality of Life Questionnaire-Core 30, Brief Pain Inventory \[worst pain\], Non-Chemotherapy Anemia Symptom Scale) will be administered before any procedure or treatment at each visit. Patient safety will be monitored throughout the study.