A Study of Subcutaneous Versus (vs.) Intravenous Administration of Daratumumab in Participants With Relapsed or Refractory Multiple Myeloma

Prior treatment

• Received daratumumab or other anti-CD38 therapies previously
• Received anti-myeloma treatment within 2 weeks or 5 pharmacokinetic half-lives of the treatment, whichever is longer, before the date of randomization. The only exception is emergency use of a short course of corticosteroids (equivalent of dexamethasone 40 mg/day for a maximum of 4 days) before treatment
• Received autologous stem cell transplant within 12 weeks before the date of randomization, or the participant has previously received allogeneic stem cell transplant (regardless of timing)
• Plans to undergo a stem cell transplant prior to progression of disease on this study (these participants should not be enrolled to reduce disease burden prior to transplant)

Other illness

• History of malignancy (other than multiple myeloma) unless all treatment of that malignancy was completed at least 2 years before consent and the patient has no evidence of disease. Further exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or breast, or other non-invasive lesion, that in the opinion of the investigator, with concurrence with the sponsor's medical monitor, is considered cured with minimal risk of recurrence within 3 years

• Evidence of a response (Partial response \[PR\] or better based on investigator's determination of response by international myeloma working group \[IMWG\] criteria) to at least 1 prior treatment regimen
• Received at least 3 prior lines of therapy including a proteasome inhibitor (PI) (greater than or equal to \[\>=\] 2 cycles or 2 months of treatment) and an immunomodulatory drug (IMiD) (\>=2 cycles or 2 months of treatment) in any order during the course of treatment (except for participants who discontinued either of these treatments due to a severe allergic reaction within the first 2 cycles/months). A single line of therapy may consist of 1 or more agents, and may include induction, hematopoietic stem cell transplantation, and maintenance therapy. Radiotherapy, bisphosphonate, or a single short course of corticosteroids (no more than the equivalent of dexamethasone 40 milligram/day \[mg/day\] for 4 days) would not be considered prior lines of therapy
• Documented multiple myeloma as defined by the criteria below:
  • Multiple myeloma diagnosis according to the IMWG diagnostic criteria
  • Measurable disease at Screening as defined by any of the following:
  • Serum M-protein level \>=1.0 gram per deciliter (g/dL) or urine M-protein level \>=200 mg/24 hours; or
  • Light chain multiple myeloma without measurable disease in the serum or the urine: Serum immunoglobulin free light chain (FLC) \>=10 mg/dL and abnormal serum immunoglobulin kappa lambda FLC ratio
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2
• Meet the clinical laboratory criteria as specified in the protocol
• Women of childbearing potential must have a negative urine or serum pregnancy test at screening within 14 days prior to randomization