Phase 1b Study Evaluating OPomD in Relapsed or Refractory Multiple Myeloma

Inclusion criteria

* Participant must have a pathologically documented, definitively diagnosed, multiple myeloma relapse, or refractory progressive disease after at least 2 lines of therapy for multiple myeloma. Prior therapeutic treatment or regimens must include a proteasome inhibitor and lenalidomide.
* Participant must be willing and able to undergo bone marrow aspirate per protocol (with or without bone marrow biopsy per institutional guidelines).
* Measurable disease (assessed within 28 days prior to day 1).
* Eastern Cooperative Oncology Group (ECOG) performance status of \<= 2.
* Other Inclusion Criteria May Apply

Exclusion Criteria

* Currently receiving treatment in another investigational device or drug study, or less than 28 days or 5 half-lives whichever is shorter since ending treatment on another investigational device or drug study(s).
* Previously received an allogeneic stem cell transplant and the occurrence of one or more of the following: received the transplant within 6 months prior to study day 1; received immunosuppressive therapy within the last 3 months prior to study day 1; having signs or symptoms of acute or chronic graft-versus-host disease.
* Autologous stem cell transplant \< 90 days prior to study day 1.
* Multiple myeloma with IgM subtype.
* POEM syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes).
* Plasma cell leukemia (\> 2.0 X10\^9/L circulating plasma cells by standard differential).
* Waldenstrom's macroglobulinemia.
* Other Exclusion Criteria May Apply