A Study Comparing Daratumumab, Lenalidomide, and Dexamethasone With Lenalidomide and Dexamethasone in Relapsed or Refractory Multiple Myeloma

This is a randomized (participants will be assigned by chance to study treatments), open-label (all participants and study personnel will know the identity of the study treatments), active-controlled (none of the study treatments are placebo), parallel-group (both treatment arms will run at the same time), multicenter study. In this study, daratumumab, lenalidomide, and low-dose dexamethasone (DRd) will be compared with lenalidomide and low dose dexamethasone (Rd) in participants with relapsed or refractory multiple myeloma. Participants will be randomized in a 1:1 ratio to receive either DRd or Rd. The study will include a Screening Phase, a Treatment Phase (involving treatment cycles of approximately 28 days in length), and a Follow-up Phase. The Treatment Phase will extend from the administration of the first dose of study medication until disease progression or unacceptable toxicity. Participants will also discontinue study treatment if: they become pregnant; have their dose held for more than 28 days (or if 3 consecutive planned doses of daratumumab are missed for reasons other than toxicity); or for safety reasons (for example, adverse event). The Follow-up Phase will begin at the end of treatment and will continue until death, loss to follow-up, consent withdrawal for study participation, or the final overall survival (OS) analysis, whichever occurs first. Eligible participants from Rd group who have had sponsor confirmed disease progression will be offered the option for treatment with daratumumab monotherapy (of 28 days cycle). The primary endpoint will be progression-free survival (PFS). Analysis of the primary endpoint was performed at a pre-specified point determined by PFS events with a clinical cutoff of March 7, 2016 when 169 events of death or progression had occurred. The end of study is anticipated at approximately 6 years after the last participant is randomized. Blood and urine samples will be obtained at time points during the study, together with bone marrow aspirates/biopsies and skeletal surveys. Participant safety will be assessed throughout the study.

Primary Outcome Measures

1. Progression-free Survival (PFS)
   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.

Secondary Outcome Measures

1. Time to Disease Progression (TTP)
   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.
2. Percentage of Participants Who Achieved Very Good Partial Response (VGPR) or Better
   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.
3. Percentage of Participants With Negative Minimal Residual Disease (MRD)
   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.
4. Overall Response Rate
   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.
5. Overall Survival (OS)
   Overall survival was measured from the date of randomization to the date of the participant's death.
6. Time to Response
   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.
7. Duration of Response (DOR)
   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.
8. Time to Subsequent Anticancer Treatment
   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.