PFS was defined as the time from randomization to the first documented disease progression (events of new bone lesions, soft tissue plasmacytomas or an increase in existing lesions, or death due to any cause). The median PFS was calculated from the product-limit (Kaplan-Meier) method for censored data. Due to the small number of events, the tail of the estimated survival distribution was close to the median for both arms. The higher variability of the tail estimates resulted in observing the median estimate in the experimental arm but not in the standard of care arm even when number of events in 2 arms were similar. The database cutoff date was July 9, 2018.

The analysis population included all randomized participants. Participants were included in the treatment group to which they were randomized.

OS was defined as the time from randomization to death due to any cause. OS was calculated from the product-limit (Kaplan-Meier) method for censored data. Participants without documented death at the time of the final analysis were censored at the date of the last follow-up. This is an event-driven (events of death) outcome measure. At the time of data cut-off, there were an insufficient number of events from the censored data to be able to estimate certain parameters (e.g. medians). The database cutoff date was August 3, 2020.

The analysis population included all randomized participants. Participants were included in the treatment group to which they were randomized.

ORR was based on participants who achieved at least a partial response (stringent complete response [sCR]+complete response [CR]+very good partial response [VGPR]+partial response [PR]) according to the IMWG. CR = negative immunofixation of serum and urine AND disappearance of any soft tissue plasmacytomas AND <5% plasmacytomas in the bone marrow; sCR=stringent complete response, CR as above PLUS normal serum free light-chain (FLC) assay ratio and absence of clonal cells in bone marrow by immunohistochemistry or immunofluorescence; VGPR = serum and urine M-component detectable by immunofixation but not on electrophoresis OR ≥ 90% reduction in serum M-component plus urine M-component <100 mg/24 hr; PR = ≥50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by ≥90% or to <200 mg/24 hours. The data cutoff date was July 9, 2018.

The analysis population included all randomized participants. Participants were included in the treatment group to which they were randomized.

Response duration was defined as the time from first documented evidence of at least a partial response (sCR+CR+VGPR+PR]), until confirmed disease progression or death. DOR was calculated from product-limit (Kaplan-Meier) method for censored data. This is an event-driven (events of disease progression and death) outcome measure. At the time of data cut-off, there were an insufficient number of events from the censored data to be able to estimate certain parameters (e.g. medians). Full Range is the minimum and maximum of the observed duration of response. The data cutoff date was July 9, 2018.

The analysis population included all randomized participants who demonstrated at least a partial response. Participants were included in the treatment group to which they were randomized.

Disease control rate was defined as the percentage of participants who achieved confirmed sCR, CR, VGPR, PR, or have demonstrated SD for at least 12 weeks prior to any evidence of progression. CR = negative immunofixation of serum and urine AND disappearance of any soft tissue plasmacytomas AND <5% plasmacytomas in the bone marrow; VGPR = serum and urine M-component detectable by immunofixation but not on electrophoresis OR ≥ 90% reduction in serum M-component plus urine M-component <100 mg/24 hr; PR = ≥50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by ≥90% or to <200 mg/24 hours; SD = not meeting the criteria for CR, VGPR, PR, or PD; PD = development of new bone lesions or soft tissue plasmacytomas or on a definite increase in the size of existing bone lesions or soft tissue plasmacytomas. Data cutoff date was July 9, 2018.

The analysis population included all randomized participants. Participants were included in the treatment group to which they were randomized.

PFS2 was defined as the time from randomization to subsequent disease progression after initiation of new anti-cancer therapy, or death from any cause, whichever occurred first, by investigator assessment. PFS was assessed by Clinical Adjudication Committee (CAC) blinded central review according to the IMWG response criteria based on the development of new bone lesions or soft tissue plasmacytomas or on a definite increase in the size of existing bone lesions or soft tissue plasmacytomas. PFS2 was not completed due to incomplete enrollment for a clinical hold and study cancellation.

The analysis population included all randomized participants. Participants were included in the treatment group to which they were randomized. PFS2 was not completed due to incomplete enrollment for a clinical hold and study cancellation.

An AE was defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it was considered related to the medical treatment or procedure, that occurred during the course of the study. The database cutoff date was August 3, 2020.

The analysis population consisted of all randomized participants who received at least one dose of study treatment.

An AE was defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it was considered related to the medical treatment or procedure, that occurred during the course of the study. The database cutoff date was August 3, 2020.

The analysis population consisted of all randomized participants who received at least one dose of study treatment.