The purpose of this study is to evaluate the tolerability and safety of Daratumumab in Japanese participants with relapsed (the return of a medical problem) or refractory (not responding to treatment) multiple myeloma (cancer of plasma cells in bone marrow, characterized by the presence of abnormal proteins in the blood).

This is a Phase 1, open-label (all participants and study personnel will know the identity of the study treatments) and multicenter (study conducted at multiple sites) study in Japanese participants. The study will include a Screening Phase, a Treatment Phase, and a Follow-up Phase. The Treatment Phase consists of 2 parts: intense dosing regimen and less intense dosing regimen. Follow-up phase will be until 8 weeks after last dose administration/death/lost to follow up/consent withdrawal for study participation or study end, whichever occurs first. The primary endpoints will be Dose Limiting Toxicity (DLTs) and overall Adverse Events (AEs) profiling. Participants' safety will be monitored throughout the study.

Inclusion Criteria:

• Participants proven to have symptomatic (having symptoms) multiple myeloma according the International Myeloma Working Group (IMWG) diagnostic criteria
• Participant must have measurable disease defined by either or both the following measurements: a) Serum M-protein greater than or equal to (>=) 1 gram per deciliter (g/dL) (>=10 gram per liter [g/L]) (except for serum immunoglobulin A [IgA] M-protein >= 0.5 g/dL); b) Urine M-protein >=200 milligram per 24 hour (mg/24 h); in case immunoglobulin D [IgD] or immunoglobulin E [IgE] M-protein, quantification should be performed
• Participant must have relapsed or refractory multiple myeloma after receiving at least 2 previous therapies, and without further established treatment options
• Participant must have an Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2
• Participant must have life expectancy greater than (>) 3 months

Exclusion Criteria:

• Participant has received daratumumab or other anti-cluster of differentiation 38 (anti-CD38) therapies previously
• Participant has received anti-myeloma treatment within 2 weeks before administration of the study drug
• Participant has previously received an allogenic stem cell transplant; or participant has received autologous stem cell transplantation (ASCT) within 12 weeks before administration of the study drug
• Participant has a history of malignancy (other than multiple myeloma) within 5 years before administration of the study drug
• Participant is exhibiting clinical signs of meningeal involvement of multiple myeloma