An adverse event was any untoward medical occurrence in a participant or clinical investigation participant administered a medicinal product and which does not necessarily had a causal relationship with this treatment. A serious adverse event was any untoward medical occurrence that at any dose, resulted in death, was life-threatening, required in-subject hospitalization or prolongation of hospitalization, resulted in persistent or significant disability or incapacity, or resulted in a congenital abnormality or birth defect, was an important medical event. A TEAE was an AE that started or worsened in severity on or after the date of the first dose of the study treatment through 30 days after the end of treatment.

The safety population included all participants who received at least 1 dose of the study treatment in Part 1. The study was terminated prior to completing Part 1 of the study. Part 2 was not started.

According to National Cancer Institute's Common Terminology Criteria for Adverse Events version 5.0, DLT was defined as any of following AE that occurred in Part 1 during first cycle of study treatment: grade (G)4 neutropenia lasting >5 days; G3 febrile neutropenia; G3 thrombocytopenia with clinically significant bleeding; G4 thrombocytopenia; G4 anemia unexplained by underlying disease; any other non-hematological toxicity ≥3 except: alopecia, G3 nausea/vomiting or diarrhea for <3 days with supportive care, G3 fatigue for <1 week, G3 or higher isolated electrolyte abnormalities for up to 3 days, not clinically complicated, and resolved spontaneously, or responded to conventional medical interventions; G3 or higher amylase/lipase elevation without symptoms of pancreatitis; G3 tumor lysis syndrome for up to 3 days, not clinically complicated, and resolved spontaneously, or responded to conventional medical interventions; and any participant meeting Hy's law criteria.

The DLT evaluable population included dose escalation dose level participants in the Safety population who received at least 80% of planned study treatment during Cycle 1.

ORR was planned to be assessed in Part 2. ORR was defined as percentage of responders as assessed by Investigator per International Myeloma Working Group (IMWG) 2016 guidelines for MM (complete response [CR], stringent CR [sCR], partial response [PR], very good PR [VGPR]) or Lugano 2014 guidelines for DLBCL (CR+PR). Per IMWG response criteria, CR: negative immunofixation on serum and urine; disappearance of soft tissue plasmacytomas; <5% plasma cells in bone marrow(BM); sCR: CR + normal free light chain (FLC) ratio; absence of BM clonal cells by immunohistochemistry; VGPR: serum and urine M-protein (MP) detected by immunofixation but not on electrophoresis or ≥90% reduction in serum MP + urine MP<100 mg/24 hours (h) or ≥90% decrease in sum of maximal perpendicular diameter (SPD) compared to baseline in soft tissue plasmacytoma; PR: ≥50% reduction of serum MP and reduction in 24 h urinary M-protein by ≥90% or to <200 mg/24 h; ≥50% reduction in size (SPD) of soft tissue plasmacytomas.

The study was terminated prior to completing Part 1 of the study. Part 2 was not started.

PFS was planned to be assessed in Part 2. PFS was defined as the time from start of treatment until the first documented progressive disease (PD), as assessed by Investigator per IMWG 2016 guidelines for MM or Lugano 2014 guidelines for DLBCL or death due to any cause, whichever occurred first. Per IMWG response criteria, PD was defined as any 1 or more of the following criteria: a) increase of ≥25% from lowest confirmed value in either serum MP, serum MP increase ≥1 gram/deciliter (g/dL) if the lowest M-component was ≥5 g/dL or urine M-component, b) appearance of new lesion(s), ≥50% increase from nadir in SPD of >1 lesion, or ≥50% increase in the longest diameter of a previous lesion >1 centimeter (cm) in short axis.

The study was terminated prior to completing Part 1 of the study. Part 2 was not started.

DCR was planned to be assessed in Part 2.DCR was defined as percentage of participants with confirmed CR,sCR,PR,VGPR,minimal response(MR) or stable disease(SD) per IMWG 2016 guidelines for MM/CR,PR, or SD per Lugano 2014 guidelines for DLBCL.Per IMWG response criteria,CR:negative immunofixation on serum and urine;disappearance of soft tissue plasmacytomas;<5% plasma cells in BM; sCR:CR+normal FLC ratio;absence of BM clonal cells by immunohistochemistry; VGPR:serum and urine MP detected by immunofixation but not electrophoresis or ≥90% reduction in serum MP+urine MP<100 mg/24h or ≥90% decrease in SPD in soft tissue plasmacytoma; PR:≥50% reduction of serum MP and reduction in 24h urinary M-protein by ≥90% or to <200mg/24h;≥50% reduction in size(SPD) of soft tissue plasmacytomas. MR:≥25% but ≤49% reduction in serum MP and reduction in 24h urine MP by 50-89%, which exceed 200 mg/24h; ≥50% reduction in size(SPD) of soft tissue plasmacytomas.SD:Not meeting criteria for CR,VGPR,PR,MR, or PD.

The study was terminated prior to completing Part 1 of the study. Part 2 was not started.

DOR was planned to be assessed in Part 2. DOR was defined as the time from initial CR or PR to documented progression or death, whichever came first, as assessed by Investigator per IMWG 2016 guidelines for MM or Lugano 2014 guidelines for DLBCL. Per IMWG response criteria, CR: negative immunofixation on serum and urine; disappearance of any soft tissue plasmacytomas; <5% plasma cells in BM. PR: ≥50% reduction of serum MP and reduction in 24 h urinary M-protein by ≥90% or to <200 mg/24 h; ≥50% reduction in the size (SPD) of soft tissue plasmacytomas. PD: any 1 or more of the following criteria: a) increase of ≥25% from lowest confirmed value in either serum MP, serum MP increase ≥1 g/dL if the lowest M-component was ≥5 g/dL or urine M-component, b) appearance of new lesion(s), ≥50% increase from nadir in SPD of >1 lesion, or ≥50% increase in the longest diameter of a previous lesion >1 cm in short axis.

The study was terminated prior to completing Part 1 of the study. Part 2 was not started.