• Participants must be actively receiving daratumumab (either as monotherapy or in combination with other study treatment) in certain Janssen research and development (R\&D) studies or receiving other study treatment in a Janssen R\&D daratumumab study for participants with multiple myeloma or smoldering multiple myeloma which has reached clinical cutoff for final analysis continue to benefit from study treatment, not have experienced disease progression or unmanageable toxicity while receiving daratumumab, not have met the withdrawal criteria set forth in the parent study, and have had the last dose of study treatment within the previous 3 months

• Investigator's assessment that the benefit of continued study treatment will outweigh the risks

• A female participant of childbearing potential must have a negative pregnancy test at screening and must agree to further serum or urine pregnancy tests during the study

• A male participant must agree not to donate sperm for the purpose of reproduction during the study and for a minimum of 3 months after receiving the last dose of study treatment

• Must sign an informed consent form (ICF; or their legally acceptable representative must sign) indicating that the participant understands the purpose of, and procedures required for, the study and is willing to participate in the study

• Willing and able to adhere to the lifestyle restrictions specified in this protocol