The following criteria is provided for health care professionals.

Inclusion Criteria:

• Documented diagnosis of multiple myeloma (MM) based on standard International Myeloma Working Group (IMWG) criteria.
• Has measurable disease at screening, defined by at least 1 of the following:
  • Serum M-protein >= 1.0 g/dL (>= 10 g/L); OR
  • Urine M-protein >= 200 mg/24 hours; OR
  • Serum free light chain (sFLC) >= 10 mg/dL (100 mg/L), provided serum FLC ratio is abnormal.
• Relapsed or refractory MM after receiving at least 3, but no more than 6 prior lines of therapy, including an immunomodulatory agent (IMiD), proteasome inhibitor (PI), and an anti-CD38 antibody, and has documented disease progression that occurred during or after the most recent therapy.
• Has adequate hematologic, hepatic and renal function as defined in the protocol.
• Eastern Cooperative Oncology Group (ECOG) 0 or 1.
• Life expectancy >= 12 weeks.

Exclusion Criteria:

• Received bortezomib as part of the most recent prior therapy.
• Has primary refractory disease defined as disease that is non-responsive.
• Has not achieved a minimal response or better per IMWG criteria with any therapy.
• Has discontinued bortezomib due to toxicity.
• History of chronic liver disease or significant unresolved liver disease; currently active (within the last 6 months) hepatic impairment according to Child-Pugh Classification B or C.
• Peripheral neuropathy Grade >= 2 or Grade 1 with pain.
• Receipt of one of the following:
  • Corticosteroids at a dose equivalent to > 4 mg daily of dexamethasone or a single dose of > 40 mg of dexamethasone within 2 weeks prior to first dose.
  • Monoclonal antibodies used for multiple myeloma treatment within 4 weeks prior to first dose of study treatment.
  • Any other systemic therapies used for multiple myeloma treatment within 5 half-lives or 2 weeks prior to first dose, whichever is longer (or 2 weeks if half-life is unknown).