PFS: duration from date of randomization to either progressive disease (PD)/death, whichever occurred first. PD: defined as meeting any 1 of following criteria: Increase of greater than equal to (>=)25 percent(%) in level of serum M-protein from lowest response value and absolute increase must be >=0.5 gram per deciliter (g/dL); Increase of >=25% in 24-hours(h) urinary light chain excretion (urine M-protein) from lowest response value and absolute increase must be >=200 mg/24h; Only in participants without measurable serum and urine M-protein levels: increase of >=25% in difference between involved and uninvolved free light chain (FLC) levels from lowest response value and absolute increase must be >10 mg/dL; Definite increase in size of existing bone lesions or soft tissue plasmacytomas; Definite development of new bone lesions or soft tissue plasmacytomas; Development of hypercalcemia (corrected serum calcium >11.5 mg/dL) attributed solely to plasma cell (PC) proliferative disorder.

Intent-to-treat (ITT) analysis set included all participants who were randomly assigned to the daratumumab, lenalidomide, dexamethasone (DRd) or lenalidomide, low-dose dexamethasone (Rd) group.

TTP was defined as time from date of randomization to date of first documented evidence of progressive disease (PD). PD was defined as meeting any one of following criteria: Increase of >=25% in level of serum M-protein from lowest response value and absolute increase must be >=0.5 g/dL; Increase of >=25% in 24-hour urinary light chain excretion (urine M-protein) from lowest response value and absolute increase must be >=200 mg/24hours; Only in participants without measurable serum and urine M-protein levels: increase of >=25% in difference between involved and uninvolved free light chain (FLC) levels from lowest response value and absolute increase must be >10 milligram per deciliter (mg/dL); Definite increase in size of existing bone lesions or soft tissue plasmacytomas; Definite development of new bone lesions or soft tissue plasmacytomas; Development of hypercalcemia (corrected serum calcium >11.5 mg/dL) that can be attributed solely to plasma cell (PC) proliferative disorder.

ITT analysis set included all participants who were randomly assigned to the DRd or Rd group.

VGPR or better is defined as the percentage of participants who achieved VGPR, complete response (CR) and stringent complete response (sCR) according to the International Myeloma Working Group criteria (IMWG). IMWG criteria for VGPR: Serum and urine M-component detectable by immunofixation but not on electrophoresis, or >=90% reduction in serum M-protein plus urine M-protein <100 mg/24 hours, if the serum and urine M-protein are not measurable, a decrease of >90% in the difference between involved and uninvolved FLC levels is required in place of the M-protein criteria. In addition to the above criteria, if present at baseline, a >=50% reduction in the size of soft tissue plasmacytomas is also required; CR: Negative immunofixation on the serum and urine, disappearance of any soft tissue plasmacytomas, and <5% PCs in bone marrow; sCR: CR and normal FLC ratio, absence of clonal PCs by immunohistochemistry, immunofluorescence or 2- to 4 color flow cytometry.

Response-evaluable set included participants who have a confirmed diagnosis of multiple myeloma and measurable disease and must have received at least 1 administration of study treatment and have at least 1 post baseline disease assessment.

Minimal residual disease was assessed for all participants who achieved a complete response (CR) or stringent complete response (sCR). CR: Negative immunofixation on the serum and urine, disappearance of any soft tissue plasmacytomas, and <5% PCs in bone marrow; sCR: CR and normal FLC ratio, absence of clonal PCs by immunohistochemistry, immunofluorescence or 2- to 4 color flow cytometry. The MRD negativity rate was defined as the percentage of participants who had negative MRD assessment at any time point after the first dose of study drugs by evaluation of bone marrow aspirates or whole blood at 10^ minus (-) 4, 10^-5, 10^-6 threshold.

ITT analysis set included all participants who were randomly assigned to the DRd or Rd group.

Overall response rate was defined as the percentage of participants who achieved a partial response (PR) or better according to the International Myeloma Working Group (IMWG) criteria, during or after study treatment. IMWG criteria for PR: >=50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by >=90% or to <200 mg/24 hours, if the serum and urine M-protein are not measurable, a decrease of >=50% in the difference between involved and uninvolved FLC levels is required in place of the M-protein criteria, in addition to the above criteria, if present at baseline, a >=50% reduction in the size of soft tissue plasmacytomas is also required.

Response-evaluable set included participants who have a confirmed diagnosis of multiple myeloma and measurable disease and must have received at least 1 administration of study treatment and have at least 1 post baseline disease assessment.

Overall survival was measured from the date of randomization to the date of the participant's death.

ITT analysis set included all participants who were randomly assigned to the DRd or Rd group. Here 'N' (number of participants analyzed) signifies number of participants who were evaluable for this outcome measure.

Time to response was defined as the time between the date of randomization and the first efficacy evaluation that the participant met all criteria for partial response (PR) or better.

Response-evaluable set is defined as participants who have a confirmed diagnosis of multiple myeloma and measurable disease at baseline or screening visit. In addition, participants must have received at least 1 administration of study treatment and have at least 1 post baseline disease assessment.

DOR was defined for participants with confirmed response (PR or better) as time between first documentation of response and disease progression/death due to PD, whichever occurs first. PD was defined as meeting any one of following criteria: Increase of >=25% in level of serum M-protein from lowest response value and absolute increase must be >=0.5g/dL; Increase of >=25% in 24-hour urinary light chain excretion (urine M-protein) from lowest response value and absolute increase must be >=200mg/24hours; Only in participants without measurable serum and urine M-protein levels: increase of >=25% in difference between involved and uninvolved FLC levels from lowest response value and absolute increase must be >10mg/dL; Definite increase in size of existing bone lesions/soft tissue plasmacytomas; Definite development of new bone lesions or soft tissue plasmacytomas; Development of hypercalcemia (corrected serum calcium >11.5mg/dL) that can be attributed solely to PC proliferative disorder.

Response-evaluable set included participants who have a confirmed diagnosis of multiple myeloma and measurable disease and must have received at least 1 administration of study treatment and have at least 1 post baseline disease assessment. Here 'N' signifies number of participants who had PR or better response.

Time to subsequent anticancer treatment was defined as the time from randomization to the start of subsequent anticancer treatment or death due to progressive disease (PD), whichever occurs first.

ITT analysis set included all participants who were randomly assigned to the DRd or Rd group, and who started subsequent anticancer therapy or died due to progressive disease, whichever occurs first.