Study to Assess Adverse Events and Change in Disease Activity of Intravenous (IV) Lemzoparlimab With or Without Oral/IV Dexamethasone and in Combination With Oral/IV/Subcutaneous Anti-Myeloma Regimens in Adult Participants With Multiple Myeloma

Inclusion Criteria: * Diagnosis of 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) criteria. * Relapsed defined as previously treated myeloma that progresses and requires initiation of salvage therapy, but does not meet criteria for refractory myeloma. * Refractory defined as disease that is nonresponsive (failure to achieve minimal response or development of progressive disease) while on primary or salvage therapy, or progresses within 60 days of last therapy. * Measurable disease per the protocol within 28 days prior to enrollment. * Arm A - Lemzoparlimab with or without Dexamethasone * For Both Escalation and Expansion Phase, participant must have refractory to 3 prior lines of treatment of anti-myeloma treatments, as outlined in the protocol. * Arm B - Lemzoparlimab + Pomalidomide-Dexamethasone * For Escalation Phase - Participant must have received at least 3 prior lines of therapy, as outlined in the protocol. * For Expansion Phase- Participant must have received at least 2 prior line of therapy, as outlined in the protocol. * Arm C - Lemzoparlimab + Carfilzomib-Dexamethasone * For Escalation Phase- Participant must have received at least 3 prior lines of therapy as outlined in the protocol. * For Expansion Phase- Participant must have received at least 1 prior line of therapy. * Arm D - Lemzoparlimab + Daratumumab-Dexamethasone -- For Both Escalation and Expansion Phase - Participant must: --- Have received at least 3 prior lines of therapy, as outlined in the protocol. Exclusion Criteria: * Arm B - Lemzoparlimab + Pomalidomide-Dexamethasone * For Both Escalation and Expansion Phase participant must have had no prior treatment with pomalidomide. * Arm C - Lemzoparlimab + Carfilzomib-Dexamethasone * For Both Escalation and Expansion Phase - prior treatment with carfilzomib. * Arm D - Lemzoparlimab + Daratumumab-Dexamethasone * For Both Escalation and Expansion Phase - prior treatment with daratumumab or other anti-CD38 therapy.