A Phase 2, Randomized, Blinded, Placebo-controlled, Multicenter Study of Siltuximab (Anti IL 6 Monoclonal Antibody) in Subjects With High-risk Smoldering Multiple Myeloma

Inclusion Criteria:

- Diagnosis of smoldering multiple myeloma (SMM) for <4 years

- Diagnosis of 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)

- Patients must be within certain limits for protocol-specified laboratory tests

- Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1

- Women not of childbearing potential must be postmenopausal, permanently sterilized,
or otherwise incapable of pregnancy

- Women of childbearing potential must agree to use adequate birth control measures and
agree to not donate eggs for the purpose of assisted reproduction during the study
and for 3 months after receiving the last dose of study agent, and must have a
negative pregnancy test at screening

- Men must agree to use a double-barrier method of birth control and to not donate
sperm during the study and for 3 months after receiving the last dose of study agent

Exclusion Criteria:

- Having symptomatic multiple myeloma, defined by any of the following (if due to
myeloma): lytic bone lesions, severe osteopenia (low bone density), pathologic
fractures, hypercalcemia (too much calcium in the blood), kidney insufficiency;
symptomatic hyperviscosity of the blood, or recurrent serious bacterial infections
such as pneumonia

- Primary systemic amyloid light (AL) chain amyloidosis (a build-up of amyloid light
chain proteins in the blood)

- Prior or concurrent exposure to approved or investigational multiple myeloma
treatments (concurrent treatment with bone-protecting agents (eg, bisphosphonates,
denosumab), or steroids (not exceeding 10 mg prednisone per day or equivalent) are
only allowed if given in a stable dose and for a nonmalignant condition; concurrent
treatment with erythropoietin-stimulating agents (ESAs) are not allowed.)

- Prior exposure to agents targeting interleukin 6 (IL 6) or the IL 6 receptor

- Other malignancy within the past 3 years, except for the following, if treated and
not active: basal cell or nonmetastatic (non-spreading) squamous cell carcinoma of
the skin, cervical carcinoma or International Federation of Gynecology and Obstetrics
Stage 1 carcinoma of the cervix