Inclusion Criteria:

- Age ≥ 18 years

- Documented pathologic diagnosis of multiple myeloma that has relapsed or failed to
respond after treatment with at least one prior systemic therapy (other than
corticosteroid monotherapy)

- Measurable disease

- At least one prior systemic therapy other than single-agent corticosteroids

- European Union patients must have had prior bone marrow transplant (autologous) or be
ineligible for transplant

- If previously received bortezomib, demonstration of clinical response of any duration
or stable disease with progression-free interval of ≥ 6 months from the start of that
therapy

- If previously received bortezomib, must have recovered from bortezomib-related
toxicities and must have a peripheral neuropathy score of Grade ≤ 1, according to the
NCI CTCAE v3.0

- If applicable, completion of autologous transplant ≥ 12 weeks prior to Day 1

- Discontinuation of previous anticancer or investigational therapy for ≥ 21 days prior
to treatment, or ≥ 90 days prior to treatment for previous monoclonal antibody
administration

Exclusion Criteria:

- Prior allogeneic bone marrow transplant

- Other invasive malignancies within 3 years prior to Day 1 except for adequately
treated basal cell or squamous cell skin cancer; carcinoma in situ of the cervix,
breast, or prostate; or other cancer of which the patient has been disease-free for ≥
3 years

- Prior anaphylactic reaction to human immunoglobulin administration

- Symptomatic hyperviscosity syndrome

- Active infection requiring parenteral antibiotics within 14 days of Day 1

- Major surgical procedure or significant traumatic injury within 28 days prior to Day
1, or anticipation of need for major surgical procedure during the course of the
study

- Clinically significant cardiac dysfunction or other significant organ dysfunction