Trial Outcomes & Findings for Sub-study of Belantamab Mafodotin (GSK2857916) as Monotherapy and in Combination With Dostarlimab (GSK4057190) in Participants With RRMM (NCT NCT06655818)

Last Updated: 2025-03-03

Results Overview

Criteria for dose-limiting toxicity (DLT) included hematologic indicators such as Grade 3-5 febrile neutropenia and thrombocytopenia with bleeding. Non-hematologic criteria, excluding corneal toxicity, comprise Grade 3-5 toxicities, with exceptions for manageable nausea, vomiting, or diarrhea, controlled Grade 3 hypertension, and events linked to disease progression. Tumor lysis syndrome (TLS) of Grade 3 or 4, successfully managed within 7 days without end-organ damage, is considered. Corneal toxicity, assessed by the GSK corneal grading scale at Grade 4, is a DLT. Other organ-specific toxicities, notably liver toxicity meeting GSK stopping criteria, also qualify as DLTs. Severity was graded using National Cancer Institute - Common Terminology Criteria for Adverse Events (version 5.0).

Recruitment status

TERMINATED

Study phase

PHASE1/PHASE2

Target enrollment

4 participants

Primary outcome timeframe

Up to 21 days

Results posted on

2025-03-03

Participant Flow

This is a sub study of the master study NCT04126200. This sub study was terminated due to lack of efficacy. The study was planned to include two phases - Dose Escalation (DE) and Cohort Expansion (CE) and no participants from this sub study were enrolled in CE phase as study was early terminated.

Participant milestones

Participant milestones
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
Overall Study STARTED	4
Overall Study COMPLETED	3
Overall Study NOT COMPLETED	1

Reasons for withdrawal

Reasons for withdrawal
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
Overall Study Withdrawal by Subject	1

Baseline Characteristics

Sub-study of Belantamab Mafodotin (GSK2857916) as Monotherapy and in Combination With Dostarlimab (GSK4057190) in Participants With RRMM

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
Age, Continuous	70.0 YEAR STANDARD_DEVIATION 9.83 • n=5 Participants
Sex/Gender, Customized Males and Females	4 Participants n=5 Participants
Race/Ethnicity, Customized Others	4 Participants n=5 Participants

PRIMARY outcome

Timeframe: Up to 21 days

Population: DLT Evaluable Population included participants in DE who have received the first course of treatment containing both agents within a sub-study and followed up within cycle 1 (Each cycle is of 21 days) or withdrew within cycle 1 due to an AE meeting the definition of a DLT.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Dose Limiting Toxicities (DLT)	1 Participants

PRIMARY outcome

Timeframe: Up to 153 weeks

Population: Safety population included all participants who received at least 1 dose of any component of the combination therapy.

An AE is any untoward medical occurrence in a clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. AEs were coded using the Medical Dictionary for Regulatory Activities (MedDRA) coding system.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Adverse Events (AEs)	4 Participants

PRIMARY outcome

Timeframe: Baseline (Day 1) and up to 153 weeks

Population: Safety Population.

Blood samples were collected for the analysis of following hematology parameters: eosinophils, anemia, hemoglobin increased, lymphocyte count decreased, lymphocyte count increased, neutrophil count decreased, platelet count decreased, leukocytosis and white blood cell decreased. Grade 1 (G1): mild; Grade 2 (G2): moderate; Grade 3 (G3): severe; Grade 4 (G4) life-threatening or disabling. Higher grade indicates greater severity and an increase in CTCAE grade was defined relative to the Baseline grade. Any worst-case post baseline increase to G1, G2, G3, and G4 are presented. The laboratory parameters were graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline White blood cell decreased, Increase to Grade 4	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Eosinophilia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Eosinophilia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Eosinophilia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Eosinophilia, Increase to Grade 4	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Anemia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Anemia, Increase to Grade 2	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Anemia, Increase to Grade 3	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Anemia, Increase to Grade 4	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hemoglobin increased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hemoglobin increased, Increase to Grade 2	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hemoglobin increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hemoglobin increased, Increase to Grade 4	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count decreased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count decreased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count decreased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count decreased, Increase to Grade 4	2 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count increased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count increased, Increase to Grade 2	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Lymphocyte count increased, Increase to Grade 4	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Neutrophil count decreased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Neutrophil count decreased, Increase to Grade 2	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Neutrophil count decreased, Increase to Grade 3	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Neutrophil count decreased, Increase to Grade 4	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Platelet count decreased, Increase to Grade 1	1 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Platelet count decreased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Platelet count decreased, Increase to Grade 3	2 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Platelet count decreased, Increase to Grade 4	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Leukocytosis, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Leukocytosis, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Leukocytosis, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline Leukocytosis, Increase to Grade 4	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline White blood cell decreased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline White blood cell decreased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Hematology Results by Maximum Grade Increase Post - Baseline Relative to Baseline White blood cell decreased, Increase to Grade 3	0 Participants

PRIMARY outcome

Timeframe: Baseline (Day 1) and up to 153 weeks

Population: Safety Population. Only those participants with data available at the specified categories were analyzed.

Blood samples were collected for the analysis of following chemistry parameters: Hypoglycemia, hypoalbuminemia, alkaline phosphatase (ALP) increased, alanine aminotransferase (ALT) increased, aspartate aminotransferase (AST) increased, blood bilirubin increased, creatine kinase (CPK) increased, creatinine increased, gamma glutamyl transferase (GGT) increased, hyperkalemia, blood lactate dehydrogenase (LDH) increased, hypermagnesemia, hypomagnesemia, hypernatremia, hypercalcemia, hypocalcemia and chronic kidney disease. G1: mild; G2: moderate; G3: severe. Higher grade indicates greater severity and an increase in CTCAE grade was defined relative to the Baseline grade. Any worst-case post baseline increase to G1, G2 and G3 are presented. The laboratory parameters were graded according to CTCAE version 5.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Blood lactate dehydrogenase increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypermagnesemia, Increase to Grade 1	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypoglycemia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypoglycemia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypoglycemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypoalbuminemia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypoalbuminemia, Increase to Grade 2	2 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypoalbuminemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Alkaline phosphatase increased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Alkaline phosphatase increased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Alkaline phosphatase increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Alanine aminotransferase increased, Increase to Grade 1	2 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Alanine aminotransferase increased, Increase to Grade 2	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Alanine aminotransferase increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Aspartate aminotransferase increased, Increase to Grade 1	2 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Aspartate aminotransferase increased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Aspartate aminotransferase increased, Increase to Grade 3	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Blood bilirubin increased, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Blood bilirubin increased, Increase to Grade 2	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Blood bilirubin increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline CPK increased, Increase to Grade 1	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline CPK increased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline CPK increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Creatinine increased, Increase to Grade 1	2 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Creatinine increased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Creatinine increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline GGT increased, Increase to Grade 1	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline GGT increased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline GGT increased, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hyperkalemia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hyperkalemia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hyperkalemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Blood lactate dehydrogenase increased, Increase to Grade 1	4 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Blood lactate dehydrogenase increased, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypermagnesemia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypermagnesemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypomagnesemia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypomagnesemia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypomagnesemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypernatremia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypernatremia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypernatremia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypercalcemia, Increase to Grade 1	1 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypercalcemia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypercalcemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypocalcemia, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypocalcemia, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Hypocalcemia, Increase to Grade 3	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Chronic Kidney Disease, Increase to Grade 1	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Chronic Kidney Disease, Increase to Grade 2	0 Participants
DE Phase: Number of Participants With Worst-Case Chemistry Results by Maximum Grade Increase Post - Baseline Relative to Baseline Chronic Kidney Disease, Increase to Grade 3	0 Participants

PRIMARY outcome

Timeframe: Up to 26 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Overall Response Rate (ORR) was defined as the percentage of participants with a confirmed PR or better as the best overall response (i.e., Partial Response \[PR\], Very Good Partial Response \[VGPR\], Complete Response \[CR\], and stringent Complete Response \[sCR\]), as assessed by the investigator per international myeloma working group (IMWG) (2016). CR defined as negative immunofixation of serum and urine AND disappearance of any soft tissue plasmacytomas AND \<5% plasmacytomas in the bone marrow; sCR defined as 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 defined as 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 h; PR defined as ≥50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by ≥90% or to \<200 mg/24 h.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Overall Response Rate (ORR)	25 Percentage of participants Interval 0.6 to 80.6

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Clinical benefit rate was defined as the percentage of participants with a confirmed minimal response (MR) or better according to the IMWG Response Criteria. MR is \>= 25% but \< 49% reduction of serum M-protein and reduction in 24-hour urinary M-protein by 50-89%.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population

Partial Response \[PR\], Very Good Partial Response \[VGPR\], Complete Response \[CR\], and stringent Complete Response \[sCR\] as assessed by the investigator per IMWG (2016). CR defined as negative immunofixation of serum and urine AND disappearance of any soft tissue plasmacytomas AND \<5% plasmacytomas in the bone marrow; sCR defined as 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 defined as 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 h; PR defined as ≥50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by ≥90% or to \<200 mg/24 h.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Percentage of Participants Achieving Stringent Complete Response (SCR), Complete Response (CR), Very Good Partial Response (VGPR) and Partial Response (PR) Stringent Complete Response (sCR)	0 Percentage of participants
DE Phase: Percentage of Participants Achieving Stringent Complete Response (SCR), Complete Response (CR), Very Good Partial Response (VGPR) and Partial Response (PR) Complete Response (CR)	0 Percentage of participants
DE Phase: Percentage of Participants Achieving Stringent Complete Response (SCR), Complete Response (CR), Very Good Partial Response (VGPR) and Partial Response (PR) Very Good Partial Response (VGPR)	25 Percentage of participants
DE Phase: Percentage of Participants Achieving Stringent Complete Response (SCR), Complete Response (CR), Very Good Partial Response (VGPR) and Partial Response (PR) Partial Response (PR)	0 Percentage of participants

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Partial Response \[PR\], Very Good Partial Response \[VGPR\], Complete Response \[CR\], and stringent Complete Response \[sCR\] as assessed by the investigator per IMWG (2016). 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 h; PR = ≥50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by ≥90% or to \<200 mg/24 h.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Predose, end of infusion (EOI), 2, and 24 hours postdose on Cycle 1 Day 1, and at Cycle 1 Day 4, Day 8, Day 22, Predose and EOI on Cycle 2 Day 1, Cycle 4 Day 1, and at end of treatment (approximately 153 weeks)

Population: Pharmacokinetic population. Only those participants with data available at the specified data points were analyzed.

Blood samples were collected for PK analysis of belantamab mafodotin Antibody-Drug Conjugate (ADC) when administered intravenously in combination with dostarlimab.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 4 DAY 1, END OF INFUSION	27600.0 Nanogram/ millilitre (ng/mL)
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 1, PRE-DOSE	0.0 Nanogram/ millilitre (ng/mL) Interval 0.0 to 0.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 1, END OF INFUSION	25300.0 Nanogram/ millilitre (ng/mL) Interval 15800.0 to 32300.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 1, 2 HOURS	26450.0 Nanogram/ millilitre (ng/mL) Interval 17900.0 to 31100.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 1, 24 HOURS	20400.0 Nanogram/ millilitre (ng/mL) Interval 8030.0 to 22200.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 4	9110.0 Nanogram/ millilitre (ng/mL) Interval 5100.0 to 14500.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 8	4830.0 Nanogram/ millilitre (ng/mL) Interval 2040.0 to 6990.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 1 DAY 22	0.0 Nanogram/ millilitre (ng/mL)
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 2 DAY 1, PRE-DOSE	1295.0 Nanogram/ millilitre (ng/mL) Interval 1050.0 to 1540.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 2 DAY 1, END OF INFUSION	41950.0 Nanogram/ millilitre (ng/mL) Interval 35000.0 to 48900.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) CYCLE 4 DAY 1, PRE-DOSE	0.0 Nanogram/ millilitre (ng/mL)
DE Phase: Belantamab Mafodotin Concentrations for Plasma Antibody-Drug Conjugate (ADC) END OF TREATMENT	0.0 Nanogram/ millilitre (ng/mL)

SECONDARY outcome

Population: Pharmacokinetic population. Only those participants with data available at the specified data points were analyzed.

Blood samples were collected for PK analysis of belantamab mafodotin total antibody when administered intravenously in combination with dostarlimab.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 1, PRE-DOSE	0.0 ng/mL Interval 0.0 to 0.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 1, END OF INFUSION	31000.0 ng/mL Interval 20700.0 to 34500.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 1, 2 HOURS	32400.0 ng/mL Interval 19800.0 to 41100.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 1, 24 HOURS	21400.0 ng/mL Interval 12600.0 to 23600.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 4	15000.0 ng/mL Interval 7810.0 to 17800.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 8	8235.0 ng/mL Interval 4530.0 to 12000.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 1 DAY 22	1140.0 ng/mL
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 2 DAY 1, PRE-DOSE	3625.0 ng/mL Interval 3480.0 to 3770.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 2 DAY 1, END OF INFUSION	45350.0 ng/mL Interval 35500.0 to 55200.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 4 DAY 1, PRE-DOSE	2800.0 ng/mL
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody CYCLE 4 DAY 1, END OF INFUSION	48900.0 ng/mL
DE Phase: Belantamab Mafodotin Concentrations for Plasma Total Antibody END OF TREATMENT	628.0 ng/mL

SECONDARY outcome

Population: Pharmacokinetic population. Only those participants with data available at the specified data points were analyzed.

Blood samples were collected for PK analysis of belantamab mafodotin cys-mcMMAF when administered intravenously in combination with dostarlimab.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 1, PRE-DOSE	0.00 ng/mL Interval 0.0 to 0.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 1, END OF INFUSION	218.00 ng/mL Interval 147.0 to 447.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 1, 2 HOURS	376.00 ng/mL Interval 231.0 to 556.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 1, 24 HOURS	750.00 ng/mL Interval 547.0 to 1670.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 4	549.50 ng/mL Interval 218.0 to 1780.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 8	170.90 ng/mL Interval 67.1 to 264.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 1 DAY 22	0.00 ng/mL
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 2 DAY 1, PRE-DOSE	0.00 ng/mL Interval 0.0 to 0.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 2 DAY 1, END OF INFUSION	555.00 ng/mL Interval 394.0 to 716.0
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 4 DAY 1, PRE-DOSE	0.00 ng/mL
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF CYCLE 4 DAY 1, END OF INFUSION	469.00 ng/mL
DE Phase: Belantamab Mafodotin Concentrations for Plasma Cys-mcMMAF END OF TREATMENT	0.00 ng/mL

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Blood samples were to be collected for PK analysis of Belantamab Mafodotin Antibody-Drug Conjugate (ADC).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Blood samples were to be collected for PK analysis of Belantamab mafodotin plasma total antibody.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Blood samples were to be collected for PK analysis of Belantamab Mafodotin Cys- Monomethyl Auristatin-F (Cys-mcMMAF)

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Predose and end of infusion (EOI) on Cycle 1 Day 1, Cycle 2 Day 1, Cycle 5 Day 1, and at the end of treatment (approximately 153 weeks)

Population: Pharmacokinetic population included all participants in the Safety population who had at least 1 non-missing PK assessment. Only those participants with data available at the specified data points were analyzed.

Blood samples were collected for PK analysis of dostarlimab when administered intravenously in combination with belantamab mafodotin.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin CYCLE 5 DAY 1, PRE-DOSE	532.0 ng/mL
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin CYCLE 1 DAY 1, PRE-DOSE	0.0 ng/mL Interval 0.0 to 203000.0
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin CYCLE 1 DAY 1, END OF INFUSION	52500.0 ng/mL Interval 0.0 to 124000.0
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin CYCLE 2 DAY 1, PRE-DOSE	43550.0 ng/mL Interval 23900.0 to 63200.0
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin CYCLE 2 DAY 1, END OF INFUSION	224000.0 ng/mL Interval 149000.0 to 299000.0
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin CYCLE 5 DAY 1, END OF INFUSION	312000.0 ng/mL
DE Phase: Dostarlimab Concentration When Administered in Combination With Belantamab Mafodotin END OF TREATMENT	35750.0 ng/mL Interval 12200.0 to 59300.0

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Blood samples were to be collected for PK analysis of dostarlimab when administered intravenously in combination with belantamab mafodotin.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population

Serum samples were collected for the analysis of the presence of ADAs using validated immunoassays. All samples were tested in screening assay, and positive samples were further characterized for antibody titers.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Post-baseline Positive Anti-drug Antibodies (ADAs) Against Belantamab Mafodotin	1 Participants

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Serum samples were to be collected for the analysis of the presence of ADAs using validated immunoassays. All samples were to be further tested in screening assay, and positive samples were further to be characterized for antibody titers.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Post-baseline Positive ADAs Against Dostarlimab	0 Participants

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population. No participants were found positive for ADAs, hence participants were not analyzed for concentration of ADAs.

Serum samples were collected for the analysis of the presence of ADAs using validated immunoassays. All samples were to be further tested in screening assay, and positive samples were further to be characterized for antibody titers.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population. Only those participants with positive post-baseline antibody against belantamab mafodotin were analyzed.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=1 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Concentration of ADAs Against Belantamab Mafodotin	NA ng/mL Standard Deviation NA Data was not estimable for 1 participant as the values were below the level of detection

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Adverse Events of Special Interest (AESI)	3 Participants

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: Safety Population

The corneal events were graded according to CTCAE version 5. Grade 1: mild; Grade 2: moderate; Grade 3: severe or medically significant. Higher grade indicates greater severity and an increase in CTCAE grade was defined relative to the Baseline grade. Results are presented for number of participants with any corneal events by maximum grade as per CTCAE grade.

Outcome measures

Outcome measures
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 Participants Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
DE Phase: Number of Participants With Any Corneal Event by Maximum Grade as Per CTCAE Grade Grade 1	1 Participants
DE Phase: Number of Participants With Any Corneal Event by Maximum Grade as Per CTCAE Grade Grade 2	0 Participants
DE Phase: Number of Participants With Any Corneal Event by Maximum Grade as Per CTCAE Grade Grade 3	0 Participants

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

The corneal events were to be graded according to CTCAE version 5. Grade 1: mild; Grade 2: moderate; Grade 3: severe or medically significant. Higher grade indicates greater severity and an increase in CTCAE grade was defined relative to the Baseline grade. Corneal Events were to be examined.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

PFS is defined as the time from randomization until the earliest date of confirmed progressive disease (PD) per IMWG, or death due to any cause.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

DoR is defined as the time from first documented evidence or PR or better until progressive disease per IMWG or death due to progressive disease among participants who achieve confirmed partial response or better.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

TTR is defined as the time between the date of randomization and the first documented evidence of response (PR or better), among participants who achieve a response (confirmed PR or better).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

OS is defined as the time from randomization until death due to any cause.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

An adverse event (AE) is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that; results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect, other situations judged by physician, is associated with liver injury and impaired liver function. AEs and SAEs were to be coded using the Medical Dictionary for Regulatory Activities (MedDRA) coding system.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Number of participants with dose reduction or delay were to be evaluated.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Blood samples were to be collected for the analysis of following hematology parameters: eosinophils, anemia, hemoglobin increased, lymphocyte count decreased, lymphocyte count increased, neutrophil count decreased, platelet count decreased, leukocytosis and white blood cell decreased. The laboratory parameters were to be graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5. Grade 1 (G1): mild; Grade 2 (G2): moderate; Grade 3 (G3): severe or medically significant. Higher grade indicates greater severity and an increase in CTCAE grade was defined relative to the Baseline grade.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to 153 weeks

Population: No participants were enrolled in CE Phase as study was terminated.

Blood samples were to be collected for the analysis of following chemistry parameters: Hypoglycemia, hypoalbuminemia, alkaline phosphatase (ALP) increased, alanine aminotransferase (ALT) increased, aspartate aminotransferase (AST) increased, blood bilirubin increased, creatine kinase (CPK) increased, creatinine increased, gamma glutamyl transferase (GGT) increased, hyperkalemia, blood lactate dehydrogenase (LDH) increased, hypermagnesemia, hypomagnesemia, hypernatremia, hypercalcemia, hypocalcemia and chronic kidney disease. The laboratory parameters were to be graded according to CTCAE version 5. G1: mild; G2: moderate; G3: severe or medically significant. Higher grade indicates greater severity and an increase in CTCAE grade was defined relative to the Baseline grade.

Outcome measures

Outcome data not reported

Adverse Events

1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab

Serious events: 2 serious events

Other events: 4 other events

Deaths: 2 deaths

Serious adverse events

Serious adverse events
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 participants at risk Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
General disorders Pyrexia	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Metabolism and nutrition disorders Hypercalcaemia	25.0% 1/4 • Number of events 2 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.

Other adverse events

Other adverse events
Measure	1.9 mg/kg Belantamab Mafodotin + 500mg Dostarlimab n=4 participants at risk Participants with Relapsed/Refractory Multiple Myeloma (RRMM) received 1.9 milligram (mg)/kilogram (kg) belantamab mafodotin intravenous (IV) infusion as powder for solution once every 3 weeks (Q3W) infused over 30- 60 minutes on day 1 of 21-day cycles in combination with 500 mg dostarlimab as a 30-minute IV infusion 1 hour after belantamab mafodotin end of infusion (EOI) on day 1 of 21-day cycles (Q3W).
Blood and lymphatic system disorders Thrombocytopenia	50.0% 2/4 • Number of events 2 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Eye disorders Dry eye	25.0% 1/4 • Number of events 2 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Eye disorders Eye irritation	25.0% 1/4 • Number of events 2 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Eye disorders Foreign body sensation in eyes	25.0% 1/4 • Number of events 2 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Eye disorders Vision blurred	50.0% 2/4 • Number of events 7 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Gastrointestinal disorders Diarrhoea	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
General disorders Pain	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
General disorders Pyrexia	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Investigations Alanine aminotransferase increased	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Investigations Aspartate aminotransferase increased	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Investigations Blood bilirubin increased	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Investigations Neutrophil count decreased	25.0% 1/4 • Number of events 3 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Metabolism and nutrition disorders Hypokalaemia	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Nervous system disorders Headache	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Respiratory, thoracic and mediastinal disorders Oropharyngeal pain	25.0% 1/4 • Number of events 1 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.
Respiratory, thoracic and mediastinal disorders Productive cough	50.0% 2/4 • Number of events 2 • All cause mortality, non-serious adverse events (Non-SAEs) and serious adverse events (SAEs) were collected maximum up to 153 weeks. Safety set included all participants who received at least 1 dose of any component of the combination therapy.

Additional Information

GSK Response Center

GlaxoSmithKline

Phone: 866-435-7343

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee GSK agreements may vary with individual investigators, but will not prohibit any investigator from publishing. GSK supports the publication of results from all centers of a multi-center trial but requests that reports based on single site data not precede the primary publication of the entire clinical trial.
Publication restrictions are in place

Restriction type: OTHER