Must have measurable disease as outlined in the protocol.
Eastern Cooperative Oncology Group (ECOG) performance of \<= 2. Arm C and Arm D: ECOG performance of \<= 1.
Relapsed/refractory (R/R) multiple myeloma (MM) with documented evidence of progression during or after the participant's last treatment regimen based on the investigator's determination of the International Myeloma Working Group (IMWG) 2016 criteria.
Must be naïve to treatment with etentamig (ABBV-383).
Arm A: Must have received at least 3 or more lines of therapy, including a proteasome inhibitor (PI), an immunomodulatory imide drug (IMiD), and an anti-CD38 monoclonal antibody.
Arm B: Must have received at least 2 or more lines of therapy, including exposure to a PI, an IMiD, an anti-CD38 monoclonal antibody, and a prior B-cell maturation antigen (BCMA)-targeted therapy (must be an anti-drug conjugate \[ADC\] or chimeric antigen receptor T-cell \[CAR-T\] directed against BCMA).
Arm C: Must have received at least 2 or more lines of therapy, including exposure to a PI, an IMiD, and an anti-CD38 monoclonal antibody. Must be suitable for outpatient administration of etentamig (ABBV-383).
Arm D: Must have received at least 1 and no more than 3 prior lines of therapy, including exposure to a PI, an IMiD, or an anti-CD38 monoclonal antibody. Must be suitable for outpatient administration of etentamig (ABBV-383).
You may not be if
Arm A: Received BCMA-targeted therapy.
Arm C and Arm D: Rapidly progressing disease per investigator.
Clareo Health | A Study to Assess Adverse Events of Intravenously (IV) Infused Etentamig (ABBV-383) in Adult Participants With Relapsed or Refractory Multiple Myeloma
