An adverse event (AE) was any untoward medical occurrence in a participant/ clinical investigational participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment. TEAEs were defined as newly occurring (not present at baseline)/worsening after first dose of investigational product (IP). TESAEs were any untoward medical occurrence at any dose that: suspected to cause death; life-threatening; required hospitalization; persistent/significant disability/incapacity & may cause congenital anomaly/birth defect. Treatment related TEAEs were related to study treatment and relatedness was judged by investigator. TEAEs were graded according to National Cancer Institute, Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version (v) 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

An AE was any untoward medical occurrence in a participant/ clinical investigational participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment. TEAEs were defined as newly occurring (not present at baseline)/worsening after first dose of IP. TESAEs were any untoward medical occurrence at any dose that: suspected to cause death; life-threatening; required hospitalization; persistent/significant disability/incapacity & may cause congenital anomaly/birth defect. Treatment related TEAEs were related to study treatment and relatedness was judged by investigator. TEAEs were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

An AE was any untoward medical occurrence in a participant/ clinical investigational participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment. TEAEs were defined as newly occurring (not present at baseline)/worsening after first dose of IP. TESAEs were any untoward medical occurrence at any dose that: suspected to cause death; life-threatening; required hospitalization; persistent/significant disability/incapacity & may cause congenital anomaly/birth defect. Treatment related TEAEs were related to study treatment and relatedness was judged by investigator. TEAEs were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

An AE was any untoward medical occurrence in a participant/ clinical investigational participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment. TEAEs were defined as newly occurring (not present at baseline)/worsening after first dose of IP. TESAEs were any untoward medical occurrence at any dose that: suspected to cause death; life-threatening; required hospitalization; persistent/significant disability/incapacity & may cause congenital anomaly/birth defect. Treatment related TEAEs were related to study treatment and relatedness was judged by investigator. TEAEs were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following serum chemistry laboratory parameters were assessed: Alanine aminotransferase high, albumin low, alkaline phosphatase high, amylase high, aspartate aminotransferase high, calcium corrected for albumin high, calcium corrected for albumin low, creatinine high, glucose high, glucose low, lipase high, phosphate low, potassium high, potassium low, sodium high, sodium low, total bilirubin high and urate high. Chemistry laboratory parameters abnormalities were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening). Participants with any serum chemistry parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following serum chemistry laboratory parameters were assessed: Alanine aminotransferase high, albumin low, alkaline phosphatase high, amylase high, aspartate aminotransferase high, calcium corrected for albumin high, calcium corrected for albumin low, creatinine high, glucose high, glucose low, lipase high, phosphate low, potassium high, potassium low, sodium high, sodium low, total bilirubin high and urate high. Chemistry laboratory parameters abnormalities were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening). Participants with any serum chemistry parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following serum chemistry laboratory parameters were assessed: Alanine aminotransferase high, albumin low, alkaline phosphatase high, amylase high, aspartate aminotransferase high, calcium corrected for albumin high, calcium corrected for albumin low, creatinine high, glucose high, glucose low, lipase high, phosphate low, potassium high, potassium low, sodium high, sodium low, total bilirubin high and urate high. Chemistry laboratory parameters abnormalities were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening). Participants with any serum chemistry parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following serum chemistry laboratory parameters were assessed: Alanine aminotransferase high, albumin low, alkaline phosphatase high, amylase high, aspartate aminotransferase high, calcium corrected for albumin high, calcium corrected for albumin low, creatinine high, glucose high, glucose low, lipase high, phosphate low, potassium high, potassium low, sodium high, sodium low, total bilirubin high and urate high. Chemistry laboratory parameters abnormalities were graded according to NCI CTCAE v 4.03 (grade 1= mild, grade 2= moderate, grade 3= severe and grade 4= life-threatening). Participants with any serum chemistry parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following hematology laboratory parameters were assessed: hemoglobin high, hemoglobin low, leukocytes high, leukocytes low, lymphocytes high, lymphocytes low, neutrophils low and platelets low. Laboratory abnormality events were graded according to NCI CTCAE v 4.03 (grade 1=mild, grade 2=moderate, grade 3= severe and grade 4= life-threatening). Participants with any hematology parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following hematology laboratory parameters were assessed: hemoglobin high, hemoglobin low, leukocytes high, leukocytes low, lymphocytes high, lymphocytes low, neutrophils low and platelets low. Laboratory abnormality events were graded according to NCI CTCAE v 4.03 (grade 1=mild, grade 2=moderate, grade 3= severe and grade 4= life-threatening). Participants with any hematology parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following hematology laboratory parameters were assessed: hemoglobin high, hemoglobin low, leukocytes high, leukocytes low, lymphocytes high, lymphocytes low, neutrophils low and platelets low. Laboratory abnormality events were graded according to NCI CTCAE v 4.03 (grade 1=mild, grade 2=moderate, grade 3= severe and grade 4= life-threatening). Participants with any hematology parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The following hematology laboratory parameters were assessed: hemoglobin high, hemoglobin low, leukocytes high, leukocytes low, lymphocytes high, lymphocytes low, neutrophils low and platelets low. Laboratory abnormality events were graded according to NCI CTCAE v 4.03 (grade 1=mild, grade 2=moderate, grade 3= severe and grade 4= life-threatening). Participants with any hematology parameter meeting CTCAE grade 1 to 4 were reported.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The DLT-evaluation period was the first cycle of treatment. DLTs were graded according to the NCI-CTCAE, v 4.03, and were defined as any of the following events during the DLT-evaluation period: a ) A delay of SEA-BCMA treatment by more than 7 days due to toxicity, b) Any AE >=Grade 3, unless deemed by the safety monitoring committee (SMC) to be clearly unrelated to SEA-BCMA except for the AEs as pre specified in protocol to be considered a DLT and c) Any treatment related death.

The DLT-evaluable (DE) analysis set included treated participants who either experienced a DLT, or were followed up for the full DLT evaluation period and received at least 75% of the intended total Cycle 1 SEA-BCMA dose, and did not receive prohibited treatment.

The DLT-evaluation period was the first cycle of treatment. DLTs were graded according to the NCI-CTCAE, v 4.03, and were defined as any of the following events during the DLT-evaluation period: a ) A delay of SEA-BCMA treatment by more than 7 days due to toxicity, b) Any AE >=Grade 3, unless deemed by the SMC to be clearly unrelated to SEA-BCMA except for the AEs as pre specified in protocol to be considered a DLT and c) Any treatment related death.

The DE analysis set included treated participants who either experienced a DLT, or were followed up for the full DLT evaluation period and received at least 75% of the intended total Cycle 1 SEA-BCMA dose, and did not receive prohibited treatment.

The DLT-evaluation period was the first cycle of treatment. DLTs were graded according to the NCI-CTCAE, v 4.03, and were defined as any of the following events during the DLT-evaluation period: a ) A delay of SEA-BCMA treatment by more than 7 days due to toxicity, b) Any AE >=Grade 3, unless deemed by the SMC to be clearly unrelated to SEA-BCMA except for the AEs as pre specified in protocol to be considered a DLT and c) Any treatment related death.

The DE analysis set included treated participants who either experienced a DLT, or were followed up for the full DLT evaluation period and received at least 75% of the intended total Cycle 1 SEA-BCMA dose, and did not receive prohibited treatment.

The DLT-evaluation period was the first cycle of treatment. DLTs were graded according to the NCI-CTCAE, v 4.03, and were defined as any of the following events during the DLT-evaluation period: a ) A delay of SEA-BCMA treatment by more than 7 days due to toxicity, b) Any AE >=Grade 3, unless deemed by the SMC to be clearly unrelated to SEA-BCMA except for the AEs as pre specified in protocol to be considered a DLT and c) Any treatment related death.

The DE analysis set included treated participants who either experienced a DLT, or were followed up for the full DLT evaluation period and received at least 75% of the intended total Cycle 1 SEA-BCMA dose, and did not receive prohibited treatment.

Area under the observed concentration-time curve from the time of dosing to Day 14 calculated by log-linear trapezoidal approximation.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here, 'Number Analyzed' signifies number of participants evaluable for the specified rows.

Area under the observed concentration-time curve from the time of dosing to Day 7 calculated by log-linear trapezoidal approximation.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

Area under the observed concentration-time curve from the time of dosing to Day 7 calculated by log-linear trapezoidal approximation.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

Area under the observed concentration-time curve from the time of dosing to Day 7 calculated by log-linear trapezoidal approximation.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

Area under the observed concentration-time curve from the time of dosing to Day 7 calculated by log-linear trapezoidal approximation.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure. 'Number Analyzed' signifies number of participants evaluable for the specified rows.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

A positive baseline ATA result was considered positive post-baseline if the post-baseline ATA titer result was at least four times higher than the baseline result.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

A positive baseline ATA result was considered positive post-baseline if the post-baseline ATA titer result was at least four times higher than the baseline result.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

A positive baseline ATA result was considered positive post-baseline if the post-baseline ATA titer result was at least four times higher than the baseline result.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

A positive baseline ATA result was considered positive post-baseline if the post-baseline ATA titer result was at least four times higher than the baseline result.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

ORR: Percentage of participants with an objective response (OR) per investigator. Participant was determined to have an OR if, based on 2016 IMWG uniform response criteria, & achieved stringent complete response (sCR), Complete response (CR), very good partial response(VGPR) & partial response(PR): free light chain(FLC) ratio & absence of clonal cells in bone marrow by immunohistochemistry(IC)/ immunofluorescence(IF). CR: negative immunofixation of serum & urine, disappearance of any soft tissue plasmacytomas(STP), 5% plasma cells in bone marrow. VGPR: serum & urine M-protein (UMP) detectable by immunofixation but not on electrophoresis/ >= 90% reduction in serum M-protein (SMP) level+UMP level <100 mg/24 hr, PR: >=50% reduction of SMP & reduction in 24-hr urinary M-protein by >=90%/to <200 mg/24 hr. If SMP & UMP are unmeasurable, a ≥50% decrease in the difference between involved & uninvolved FLC levels were required in place of the M-protein criteria.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The ORR was defined as the percentage of participants with an OR per investigator. A participant was determined to have an OR if, based on the 2016 IMWG uniform response criteria, and achieved a sCR, CR, VGPR, or a PR. sCR: FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: negative immunofixation of serum & urine, disappearance of any STP, 5% plasma cells in bone marrow. VGPR: serum and UMP detectable by immunofixation but not on electrophoresis or >= 90% reduction in SMP level+UMP level <100 mg/24 hour, PR: >=50% reduction of SMP & reduction in 24-hour urinary M-protein by >=90%/to <200 mg/24 hour. If SMP & UMP are unmeasurable, a ≥50% decrease in the difference between involved & uninvolved FLC levels were required in place of the M-protein criteria. In addition to above criteria, if present at baseline, >=50% reduction in the size of STP were also required.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The ORR was defined as the percentage of participants with an OR per investigator. A participant was determined to have an OR if, based on the 2016 IMWG uniform response criteria, and achieved a sCR, CR, VGPR, or a PR. sCR: FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: negative immunofixation of serum & urine, disappearance of any STP, 5% plasma cells in bone marrow. VGPR: serum and UMP detectable by immunofixation but not on electrophoresis or >= 90% reduction in SMP level+UMP level <100 mg/24 hour, PR: >=50% reduction of SMP & reduction in 24-hour urinary M-protein by >=90%/to <200 mg/24 hour. If SMP & UMP are unmeasurable, a ≥50% decrease in the difference between involved & uninvolved FLC levels were required in place of the M-protein criteria. In addition to above criteria, if present at baseline, >=50% reduction in the size of STP were also required.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

The ORR was defined as the percentage of participants with an OR per investigator. A participant was determined to have an OR if, based on the 2016 IMWG uniform response criteria, and achieved a sCR, CR, VGPR, or a PR. sCR: FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: negative immunofixation of serum & urine, disappearance of any STP, 5% plasma cells in bone marrow. VGPR: serum and UMP detectable by immunofixation but not on electrophoresis/ >= 90% reduction in SMP level+UMP level <100 mg/24 hour, PR: >=50% reduction of SMP & reduction in 24-hour urinary M-protein by >=90%/to <200 mg/24 hour. If SMP & UMP are unmeasurable, a ≥50% decrease in the difference between involved & uninvolved FLC levels were required in place of the M-protein criteria. In addition to above criteria, if present at baseline, >=50% reduction in the size of STP were also required.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

BOR consisted of MRD-negative CR,sCR,CR,VGPR,PR,MR,SD & PD per 2016 IMWG. MRD: evaluated using adaptive next generation sequencing(NGS) for MRD assay & carried out on relevant specimen to understand activity of SEA-BCMA. sCR: CR & normal FLC ratio & absence of clonal cells in bone marrow by IC/ IF. CR: Negative immunofixation of serum & urine disappearance of any STP, & <5% plasma cells in bone marrow. VGPR: SMP & UMP detectable by IF but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hr, PR: >=50% R of SMP & R in 24-hr UMP by >=90%/by <200 mg/24 hr. If SMP & UMP are unmeasurable, >=50% decrease in difference between involved & uninvolved FLC levels were required in place of M-protein criteria. SD: Not meeting criteria for CR, VGPR, PR, MR, or progression. MR: 25-49% R of SMP & R in 24-hr UMP by 50-89%, which still exceeds 200mg/24 hr. DP: objective evidence of tumor progression(based on serum/urine/BM assessments) &/clinical progression/investigator.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

BOR consisted of MRD-negative CR, sCR, CR, VGPR, PR, MR, SD & PD per 2016 IMWG. MRD: evaluated using adaptive NGS for MRD assay & carried out on relevant specimen to understand activity of SEA-BCMA. sCR: CR & normal FLC ratio & absence of clonal cells in bone marrow by IC/ IF. CR: Negative immunofixation of serum & urine disappearance of any STP, & <5% plasma cells in bone marrow. VGPR: SMP & UMP detectable by IF but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hr, PR: >=50% R of SMP & R in 24-hr UMP by >=90%/by <200 mg/24 hr. If SMP & UMP are unmeasurable, >=50% decrease in difference between involved & uninvolved FLC levels were required in place of M-protein criteria. SD: Not meeting criteria for CR, VGPR, PR, MR, or progression. MR: 25-49% R of SMP & R in 24-hr UMP by 50-89%, which still exceeds 200mg/24 hr. DP: objective evidence of tumor progression(based on serum/urine/BM assessments) &/clinical progression/investigator.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

BOR consisted of MRD-negative CR, sCR, CR, VGPR, PR, MR, SD & PD per 2016 IMWG. MRD: evaluated using NGS for MRD assay & carried out on relevant specimen to understand activity of SEA-BCMA. sCR: CR & normal FLC ratio & absence of clonal cells in bone marrow by IC/ IF. CR: Negative immunofixation of serum & urine disappearance of any STP, & <5% plasma cells in bone marrow. VGPR: SMP & UMP detectable by IF but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hr, PR: >=50% R of SMP & R in 24-hr UMP by >=90%/by <200 mg/24 hr. If SMP & UMP are unmeasurable, >=50% decrease in difference between involved & uninvolved FLC levels were required in place of M-protein criteria. SD: Not meeting criteria for CR, VGPR, PR, MR, or progression. MR: 25-49% R of SMP & R in 24-hr UMP by 50-89%, which still exceeds 200mg/24 hr. DP: objective evidence of tumor progression(based on serum/urine/BM assessments) &/clinical progression/investigator.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

BOR consisted of MRD-negative CR,sCR,CR,VGPR,PR,MR,SD & PD per 2016 IMWG. MRD: evaluated using adaptive NGS for MRD assay & carried out on relevant specimen to understand activity of SEA-BCMA. sCR: CR & normal FLC ratio & absence of clonal cells in bone marrow by IC/ IF. CR: Negative immunofixation of serum & urine disappearance of any STP, & <5% plasma cells in bone marrow. VGPR: SMP & UMP detectable by IF but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hr, PR: >=50% R of SMP & R in 24-hr UMP by >=90%/by <200 mg/24 hr. If SMP & UMP are unmeasurable, >=50% decrease in difference between involved & uninvolved FLC levels were required in place of M-protein criteria. SD: Not meeting criteria for CR, VGPR, PR, MR, or progression. MR: 25-49% R of SMP & R in 24-hr UMP by 50-89%, which still exceeds 200mg/24 hr. DP: objective evidence of tumor progression(based on serum/urine/BM assessments) &/clinical progression/investigator.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

DOR: Time from first documentation of OR(sCR,CR,VGPR/PR) to first documentation of PD/death due to any cause, whichever came first. PD: Objective evidence of tumor progression(TP) (based on serum, urine/BM assessments) &/clinical progression/ investigator. sCR: CR, normal FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: Negative immunofixation of serum&urine, disappearance of any STP, &<5% plasma cells in bone marrow. VGPR: Serum & UMP detectable by immunofixation but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hour, PR: >=50%R of SMP & R in 24-hour UMP by >=90% or to <200 mg/24 hour. DOR: censored on date of last disease assessment documenting absence of PD for participants who do not have PD & were still on study at the time of an analysis/removed from study prior to documentation of TP. Participants started new antitumor treatment prior to documentation of PD were censored at last disease assessment prior to start of new treatment.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

DOR: Time from first documentation of OR(sCR,CR,VGPR/PR) to first documentation of PD/death due to any cause, whichever came first. PD: Objective evidence of tumor progression(TP) (based on serum, urine/BM assessments) &/clinical progression/ investigator. sCR: CR, normal FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: Negative immunofixation of serum&urine, disappearance of any STP, &<5% plasma cells in bone marrow. VGPR: Serum & UMP detectable by immunofixation but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hour, PR: >=50%R of SMP & R in 24-hour UMP by >=90% or to <200 mg/24 hour. DOR: censored on date of last disease assessment documenting absence of PD for participants who do not have PD & were still on study at the time of an analysis/removed from study prior to documentation of TP. Participants started new antitumor treatment prior to documentation of PD were censored at last disease assessment prior to start of new treatment.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

DOR: Time from first documentation of OR(sCR,CR,VGPR/PR) to first documentation of PD/death due to any cause, whichever came first. PD: Objective evidence of tumor progression(TP) (based on serum, urine/BM assessments) &/clinical progression/ investigator. sCR: CR, normal FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: Negative immunofixation of serum&urine, disappearance of any STP, &<5% plasma cells in bone marrow. VGPR: Serum & UMP detectable by immunofixation but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hour, PR: >=50%R of SMP & R in 24-hour UMP by >=90% or to <200 mg/24 hour. DOR: censored on date of last disease assessment documenting absence of PD for participants who do not have PD & were still on study at the time of an analysis/removed from study prior to documentation of TP. Participants started new antitumor treatment prior to documentation of PD were censored at last disease assessment prior to start of new treatment.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

DOR: Time from first documentation of OR(sCR,CR,VGPR/PR) to first documentation of PD/death due to any cause, whichever came first. PD: Objective evidence of tumor progression(TP) (based on serum, urine/BM assessments) &/clinical progression/ investigator. sCR: CR, normal FLC ratio & absence of clonal cells in bone marrow by IC/IF. CR: Negative immunofixation of serum&urine, disappearance of any STP, &<5% plasma cells in bone marrow. VGPR: Serum & UMP detectable by immunofixation but not on electrophoresis/ >= 90% reduction(R) in SMP level+UMP level <100 mg/24 hour, PR: >=50%R of SMP & R in 24-hour UMP by >=90% or to <200 mg/24 hour. DOR: censored on date of last disease assessment documenting absence of PD for participants who do not have PD & were still on study at the time of an analysis/removed from study prior to documentation of TP. Participants started new antitumor treatment prior to documentation of PD were censored at last disease assessment prior to start of new treatment.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA. Here "Number of Participants Analyzed" signifies participants evaluable for this outcome measure.

PFS: Time from the start of any study treatment to first documentation of DP or to death due to any cause, whichever comes first. DP included objective evidence of tumor progression (based on serum, urine or BM assessments) and/or clinical progression per investigator. PFS was censored on the date of the last disease assessment documenting absence of PD for participants who do not have disease progression and are still on study at the time of an analysis, or discontinuation of study prior to documentation of tumor progression. Participants who have started a new antitumor treatment prior to documentation of PD were censored at the last disease assessment prior to start of new treatment. Participants lacking an evaluation of tumor response after their first dose had their event time censored as 1 day.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

PFS: Time from the start of any study treatment to first documentation of DP or to death due to any cause, whichever comes first. DP included objective evidence of tumor progression (based on serum, urine or BM assessments) and/or clinical progression per investigator. PFS was censored on the date of the last disease assessment documenting absence of PD for participants who do not have disease progression and are still on study at the time of an analysis, or discontinuation of study prior to documentation of tumor progression. Participants who have started a new antitumor treatment prior to documentation of PD were censored at the last disease assessment prior to start of new treatment. Participants lacking an evaluation of tumor response after their first dose had their event time censored as 1 day.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

PFS: Time from the start of any study treatment to first documentation of DP or to death due to any cause, whichever comes first. DP included objective evidence of tumor progression (based on serum, urine or BM assessments) and/or clinical progression per investigator. PFS was censored on the date of the last disease assessment documenting absence of PD for participants who do not have disease progression and are still on study at the time of an analysis, or discontinuation of study prior to documentation of tumor progression. Participants who have started a new antitumor treatment prior to documentation of PD were censored at the last disease assessment prior to start of new treatment. Participants lacking an evaluation of tumor response after their first dose had their event time censored as 1 day.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

PFS: Time from the start of any study treatment to first documentation of DP or to death due to any cause, whichever comes first. DP included objective evidence of tumor progression (based on serum, urine or BM assessments) and/or clinical progression per investigator. PFS was censored on the date of the last disease assessment documenting absence of PD for participants who do not have disease progression and are still on study at the time of an analysis, or discontinuation of study prior to documentation of tumor progression. Participants who have started a new antitumor treatment prior to documentation of PD were censored at the last disease assessment prior to start of new treatment. Participants lacking an evaluation of tumor response after their first dose had their event time censored as 1 day.

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

OS was defined as the time from the start of any study treatment to the date of death due to any cause. OS was calculated as date of death minus date of first dose of any study treatment plus 1. OS for participants who were alive at their date of last contact, including those lost to follow-up, were censored at the date of last contact. If the last recorded date where a participant was known to be alive is the date of first dose of any study treatment, survival time was censored on the date of first dose of any study treatment (i.e., OS duration of 1 day).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

OS was defined as the time from the start of any study treatment to the date of death due to any cause. OS was calculated as date of death minus date of first dose of any study treatment plus 1. OS for participants who were alive at their date of last contact, including those lost to follow-up, were censored at the date of last contact. If the last recorded date where a participant was known to be alive is the date of first dose of any study treatment, survival time was censored on the date of first dose of any study treatment (i.e., OS duration of 1 day).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

OS was defined as the time from the start of any study treatment to the date of death due to any cause. OS was calculated as date of death minus date of first dose of any study treatment plus 1. OS for participants who were alive at their date of last contact, including those lost to follow-up, were censored at the date of last contact. If the last recorded date where a participant was known to be alive is the date of first dose of any study treatment, survival time was censored on the date of first dose of any study treatment (i.e., OS duration of 1 day).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.

OS was defined as the time from the start of any study treatment to the date of death due to any cause. OS was calculated as date of death minus date of first dose of any study treatment plus 1. OS for participants who were alive at their date of last contact, including those lost to follow-up, were censored at the date of last contact. If the last recorded date where a participant was known to be alive is the date of first dose of any study treatment, survival time was censored on the date of first dose of any study treatment (i.e., OS duration of 1 day).

All treated participants analysis set included all treated participants who received any amount of SEA-BCMA.