Phase 1/2 Dose Escalation and Efficacy Study of Anti-CD38 Monoclonal Antibody in Patients With Selected CD38+ Hematological Malignancies

Sanofi351 enrolled

Overview

Primary Objective: Phase 1: To determine the maximum tolerated dose (MTD)/maximum administered dose (MAD) of SAR650984 (Isatuximab). Phase 2 (stage 1): To evaluate the activity of single-agent Isatuximab at different doses/schedules and to select dose and regimen to further evaluate the overall response rate (ORR) of Isatuximab as single agent or in combination with dexamethasone. Phase 2 (stage 2): To evaluate the activity in terms of overall response rate (ORR) of Isatuximab at the selected dose/schedule from stage1, as single agent (ISA arm) and in combination with dexamethasone (ISAdex arm). Secondary Objectives: Phase 1: * To characterize the global safety profile including cumulative toxicities. * To evaluate the pharmacokinetic (PK) profile of Isatuximab in the proposed dosing schedule(s). * To assess the pharmacodynamics (PD), immune response, and preliminary disease response. Phase 2 (stage 1): to evaluate the following objectives for Isatuximab as single agent: * Safety * Efficacy as measured by duration of response, clinical benefit rate, progression free survival, overall survival. Phase 2 (stage 2): to evaluate the following objectives in each arm (ISA and ISAdex): * Safety * Efficacy as measured by duration of response, clinical benefit rate, progression free survival, overall survival. * Participant-reported changes in health-related quality of life, symptoms of multiple myeloma and generic health status. * Pharmacokinetic profile of Isatuximab. * Immunogenicity of Isatuximab. * Investigate the relationship between CD38 receptor density and CD38 receptor occupancy (Stage 1 only) on multiple myeloma cells and parameters of clinical response.

The Phase 1 study duration for an individual participant included a screening period for inclusion of up to 2 weeks, treatment with Isatuximab QW (every week) or Q2W (every 2 weeks) unless discontinued earlier due to safety or disease progression. Participants were followed for a minimum of 30 days following the last use of study drug or more than 30 days in case of unresolved toxicity, or up to initiation of another anticancer treatment. The Phase 2 study duration for an individual participant included a screening period for inclusion of up to 3 weeks, then a treatment period and a follow up period. Treatment was continued until disease progression, unacceptable adverse reactions or other reasons for discontinuation. Participants were followed every 3 months following the last use of study drug until death or study cutoff, whichever came first.

Study Type

INTERVENTIONAL

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion criteria: Phase 1: * For dose escalation cohorts, participants with confirmed selected CD38+ hematological malignancies as specified below who had progressed on after standard therapy or for whom there was no effective standard therapy (refractory/relapsed participants). B-cell Non-Hodgkin-lymphoma/leukemia (NHL) participants with at least 1 measurable lesion. Multiple myeloma (MM) participants with measurable M-protein serum and/or 24-hour urine. Acute myeloid leukemia (AML) participants, all types except M3 based on French-American-British (FAB) classification. Acute Lymphoblastic Leukemia (B-cell ALL) participants. Chronic lymphocytic leukemia (CLL) participants. * For expansion cohorts, participants with relapsed/refractory MM with measurable M-protein (serum M-protein of \>0.5 g/dL and/or urine M-protein of \>200 mg (24-hr urine)) or elevated serum free light chains (FLC) \>10 mg/dL with abnormal FLC ratio) who had progressed on or after standard therapy that included an Immunomodulatory drug (IMiD) and a proteasome inhibitor and who met the protocol defined criteria for standard risk or high risk. Phase 2: * Participants had a known diagnosis of multiple myeloma with evidence of measurable disease, and have evidence of disease progression based on International Myeloma Working Group (IMWG) criteria: Serum M-protein ≥1 g/dL, or urine M-protein \>=200 mg/24 hours or in the absence of measurable m-protein, serum FLC \>=10 mg/dL, and abnormal serum immunoglobulin kappa lambda FLC ratio (\<0.26 or \>1.65). * Participants who received at least three prior lines of therapy for MM and had treatment with an IMiD (for \>=2 cycles or \>=2 months of treatment) and a proteasome inhibitor (PI) (for \>=2 cycles or \>=2 months of treatment) OR participants whose disease was double refractory to an IMiD and a PI. For participants who had received more than 1 type of IMiD and PI, their disease must be refractory to the most recent one. * Participants who had achieved a minimal response or better to at least one prior line of therapy. * Participants who had received an alkylating agent (\>=2 cycles or \>=2 months) either alone or in combination with other MM treatments. * Stage 2 only: Participants who had evidence of disease progression on or after the most recent prior regimen based on IMWG criteria. Exclusion criteria: Phase 1: * Karnofsky performance status \<60 * Poor bone marrow reserve * Poor organ function * Known intolerance to infused protein products, sucrose, histidine, polysorbate 80 or known hypersensitivity to any of the components of the study therapy that was not amenable to pre-medication with steroids and H2 blockers * Any serious active disease (including clinically significant infection that was chronic, recurrent, or active) or co-morbid condition, which, in the opinion of the investigator, interfered with the safety, the compliance with the study or with the interpretation of the results * Any severe underlying medical conditions including presence of laboratory abnormalities, which could impair the ability to participate in the study or the interpretation of its results Phase 2: * Participants with multiple myeloma immunoglobulin M (IgM) subtype * Previous treatment with any anti-CD38 therapy * Participants with concurrent plasma cell leukemia * Participants with known or suspected amyloidosis * Karnofsky performance status \<60 (stage 1)/Eastern Cooperative Oncology Group (ECOG) Performance status \>2 (stage 2). * Poor bone marrow reserve * Poor organ function * Known intolerance to infused protein products, sucrose, histidine, polysorbate 80 or known hypersensitivity to any of the components of the study therapy that was not amenable to pre-medication with steroids and H2 blockers * Any serious active disease (including clinically significant infection that was chronic, recurrent, or active) or co-morbid condition, which, in the opinion of the investigator, interfered with the safety, the compliance with the study or with the interpretation of the results * Any severe underlying medical conditions including presence of laboratory abnormalities, which impaired the ability to participate in the study or the interpretation of its results The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Locations (59)

Mayo Clinic Site Number : 840003

Scottsdale, Arizona, United States

UCSF MS Center Site Number : 840005

San Francisco, California, United States

Emory University Site Number : 840009

Atlanta, Georgia, United States

University of Chicago Site Number : 840010

Chicago, Illinois, United States

The University Of Michigan Site Number : 840022

Ann Arbor, Michigan, United States

Outcomes

Primary Outcomes

Phase 1: Number of Participants With Dose Limiting Toxicities (DLTs)

DLTs were assessed using the national cancer institute common terminology criteria for adverse events (NCI-CTCAE) version 4.03. DLTs were defined as any Grade 3 or higher non-hematological toxicity (with the exception of allergic reaction/hypersensitivity), Grade 4 neutropenia and/or Grade 4 thrombocytopenia lasting longer than 5 days, attributed to isatuximab. Any other toxicity that the Investigator and the Sponsor deemed to be dose-limiting, regardless of the grade, was also considered as DLT.

Time frame: Day 1 of Cycle 1 up to Day 14 of Cycle 2

Phase 1: Number of Participants With Treatment Emergent Adverse Events (TEAEs)

Adverse event (AE) was defined as any untoward medical occurrence in a participant who received study drug and did not necessarily have to have a causal relationship with the treatment. TEAEs were defined as AEs that developed or worsened during the on-treatment period which was defined as the period from the time of first dose of study treatment until 30 days after the last dose of study treatment.

Time frame: From Baseline up to 30 days after the last dose (maximum duration: 120 weeks )

Phase 2 Stage 1: Percentage of Participants With Overall Response (OR) According to International Myeloma Working Group (IMWG) Uniform Response Criteria

OR defined as participants with stringent complete response (sCR) or complete response (CR) or very good partial response (VGPR) or partial response (PR) . Based on IMWG, CR: Negative serum and urine on immunofixation, disappearance of any soft tissue plasmacytomas and \<=5% plasma cells in bone marrow; sCR: CR and normal free light chain (FLC) ratio and no clonal cells in bone marrow; VGPR: Serum and urine M-protein detectable by immunofixation but not on electrophoresis or \>=90% reduction in serum M-protein and urine M-protein level \<100 mg/24 hours; PR: \>=50% reduction of serum M-Protein and reduction in urinary M-protein by \>=90% or to \<200 mg/24 hours; \>=50% decrease in the difference between involved and uninvolved FLC levels in place of the M-protein criteria or a \>=50% reduction in plasma cells in place of M-protein if present at baseline.

Time frame: From the date of randomization until disease progression or death or data cut-off (maximum duration: 77 weeks for Stage 1a arms and 53 weeks for Stage 1b arm)

Phase 2 Stage 2: Percentage of Participants With Overall Response According to Updated IMWG Response Criteria

OR: participants with sCR or CR or VGPR or PR. As per updated IMWG, CR: Negative immunofixation on serum and urine, disappearance of any soft tissue plasmacytomas and \<=5% plasma cells in bone marrow; normal FLC ratio of 0.26-1.65 in participants with only FLC disease; sCR: CR and normal FLC ratio and no clonal cells in bone marrow; VGPR: Serum and urine M-protein detectable by immunofixation but not on electrophoresis or \>=90% reduction in serum M-protein and urine M-protein level \<100 mg/24 hours, \>90% decrease in the difference between involved and uninvolved FLC levels; PR: \>=50% reduction of serum M-Protein and reduction in urinary M-protein by \>=90% or to \<200 mg/24 hours; \>=50% decrease in the difference between involved and uninvolved FLC levels in place of M-protein criteria or \>=50% reduction in plasma cells in place of M-protein if present at baseline.

Time frame: From the date of randomization to date of death from any cause (maximum duration: 97 weeks)

Secondary Outcomes

Pharmacokinetic (PK) Assessment: Phase 1: Plasma Concentration of Isatuximab Observed at the End of an Intravenous Infusion (Ceoi)

Ceoi was defined as the plasma concentration of Isatuximab at end of infusion. Data for this outcome measure was planned to be collected and analyzed separately for dose 0.3 mg/kg, 1 mg/kg and not for 0.0001, 0.001, 0.01, 0.03 and 0.1 dose levels (reported under one arm, i.e. Phase 1: Isatuximab \<=1mg/kg in participant flow). Analysis was performed on PK population: participants who gave informed consent, received at least one dose (even if incomplete) of isatuximab, had an assessable PK parameter.

Time frame: Cycle 1 Day 1 and Cycle 3 Day 1: At the end of infusion

PK Assessment: Phase 1: Maximum Observed Plasma Concentration (Cmax) of Isatuximab

Data for this outcome measure was planned to be collected and analyzed separately for dose 0.3 mg/kg, 1 mg/kg and not for 0.0001, 0.001, 0.01, 0.03 and 0.1 dose levels (reported under one arm, i.e. Phase 1: Isatuximab \<=1mg/kg in participant flow). Analysis was performed on PK population.

Time frame: For Q2W:Cycle 1,Day 1: pre-dose, 15 min after start of infusion, at the end of infusion, 3, 7, 24, 48 and 168 hr post-infusion; For QW: Cycle 1,Day 1: pre-dose, 15 min after start of infusion, at the end of infusion, 4, 24, 48, 72 and 168 hr post-infusion

PK Assessment: Phase 1: Time to Reach Maximum Plasma Concentration Observed (Tmax) of Isatuximab

PK Assessment: Phase 1: Plasma Concentration of Isatuximab at Week 1, 2 and 3

Data for this outcome measure was planned to be collected and analyzed only for dose 1 mg/kg and not for 0.0001, 0.001, 0.01, 0.03, 0.1 and 0.3 mg/kg dose levels (reported under one arm, i.e. Phase 1: Isatuximab \<=1mg/kg in participant flow).

PK Assessment: Phase 1: Predicted Cumulative Area Under the Plasma Concentration Curve (AUC) of Isatuximab Over the First Week (0-168 Hours) (AUC1W)

PK Assessment: Phase 1: Predicted Cumulative Area Under the Plasma Concentration Curve (AUC) of Isatuximab Over the First 2 Weeks (0-336 Hours) (AUC2W)

Time frame: For Q2W:Cycle 1,Day 1: pre-dose, 15 min after start of infusion, at the end of infusion, 3, 7, 24, 48 and 336 hr post-infusion; For QW: Cycle 1,Day 1: pre-dose, 15 min after start of infusion, at the end of infusion, 4, 24, 48, 72 and 336 hr post-infusion

Immunogenicity Assessment: Phase 1: Number of Participants With Treatment-Emergent And Treatment-Boosted Anti-drug Antibodies (ADA) Response

ADA response was categorized as: treatment induced and treatment boosted response. Treatment-induced ADA was defined as ADA that developed at any time during the ADA on-study observation period (defined as the time from the first isatuximab administration until end of Phase 1) in participants without preexisting ADA (defined as: ADA that were present in samples drawn before treatment), including participants without pre-treatment (before treatment) samples. Treatment boosted ADA was defined as pre-existing ADA that increased at least 2 titer steps between pre-treatment (before treatment) and post-treatment.

Time frame: Up to 120 weeks

Clinical Assessment: Phase 1: Percentage of Participants With Overall Response and Clinical Benefit: Assessed Using European Society for Blood and Marrow Transplantation (EBMT) Criteria

OR defined as participants with complete response (CR) or partial response (PR) as best overall response (BOR). Clinical benefit: participants with minimal response (MR) or better as BOR. BOR: best sequential response from start of treatment through the entire study excluding any time point following start of other treatment. CR: negative immunofixation on serum and urine, disappearance of any soft tissue plasmacytomas, \<5% plasma cells in bone marrow aspirates, no increase in size or number of lytic bone lesions. PR: \>=50% reduction of serum M-protein, reduction in 24 h urinary M-protein by \>=90% or \<200mg, \>=50% reduction in size/number of soft tissue plasmacytomas, no increase in size or number of lytic bone lesions. MR: 25 to 49% reduction in serum M-protein, 50-89% reduction in 24h urine M-protein, 25-49% reduction in size of soft tissue plasmacytomas, no increase in size or number of lytic bone lesions.

Time frame: From the date of randomization to the date of first documentation of progression or death (due to any cause) (maximum duration: 120 weeks)

Clinical Assessment: Phase 1: Duration of Response (DOR)

DOR: time from first response (PR or better) to first documented tumor progression/death. Progression as per EBMT: \>25% increase in serum monoclonal paraprotein level, which must also be an absolute increase of \>= 5 g/l: confirmed by \>=1 repeated investigation; \>25% increase in 24h urinary light chain excretion, which must also be an absolute increase of \>=200 mg/24 h:confirmed by \>=1 repeated investigation; \>25% increase in plasma cells in a bone marrow aspirate/on trephine biopsy, which must also be an absolute increase of \>= 10%; definite increase in size of existing bone lesions/soft tissue plasmacytomas; development of new bone lesions/soft tissue plasmacytomas; development of hypercalcemia (corrected serum calcium \>11·5 mg/dl or 2·8 mmol/l) not attributable to any other cause. PR: \>=50% reduction of serum M-protein, reduction in 24h urinary M-protein by \>=90% or \<200mg, \>=50% reduction in size/number of soft tissue plasmacytomas, no increase in size/number of lytic bone lesions.

Time frame: From the date of first response to the date of first documentation of progression or death (due to any cause) (maximum duration: 120 weeks)

Clinical Assessment: Phase 1: Time to First Response (TTR)

TTR was defined as the time from first dose of isatuximab to first response (PR or better). PR: \>=50% reduction of serum M-protein, reduction in 24 h urinary M-protein by \>=90% or \<200mg, \>=50% reduction in size/number of soft tissue plasmacytomas, no increase in size or number of lytic bone lesions.

Time frame: From the date of first dose administration to the date of first response or death (due to any cause) (maximum duration: 120 weeks)

Clinical Assessment: Phase 1: Number of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) (Karnofsky Performance Status)-Shift From Baseline Value to Best Value During Treatment

ECOG performance status was measured on a 4 point scale to assess participant's performance status. 0=Normal, fully functional; 1=Fatigue without significant decrease in daily activity; 2=Fatigue with significant impairment of daily activities or bed rest \<50% of waking hours; 3=Bed rest/sitting \>50% of waking hours; 4=Bedridden or unable to care for self, where lower score indicated good performance status. Number of participants with Baseline ECOG PS score and corresponding changes to the best values (categorized as: Baseline ECOG 1, During Treatment ECOG 0; Baseline ECOG 2, During Treatment ECOG 0; Baseline ECOG 2, During Treatment ECOG 1) are reported.

Time frame: At baseline, during treatment (Day 1 up to 120 weeks)

Clinical Assessment: Phase 1: Number of Participants With Eastern Cooperative Oncology Group Performance Status (Karnofsky Performance Status)-Shift From Baseline Value to Worst Value During Treatment

ECOG performance status was measured on a 4 point scale to assess participant's performance status. 0=Normal, fully functional; 1=Fatigue without significant decrease in daily activity; 2=Fatigue with significant impairment of daily activities or bed rest \<50% of waking hours; 3=Bed rest/sitting\>50% of waking hours; 4=Bedridden or unable to care for self, where higher score indicated worst performance status. Number of participants with Baseline ECOG PS score and corresponding changes to the worst values (categorized as: Baseline ECOG 0, During Treatment ECOG 1; Baseline ECOG 2, During Treatment ECOG 1; Baseline ECOG 0, During Treatment ECOG 2; Baseline ECOG 1, During Treatment ECOG 2; Baseline ECOG 0, During Treatment ECOG 3; Baseline ECOG 1, During Treatment ECOG 3; Baseline ECOG 2, During Treatment ECOG 3) are reported.

Time frame: At baseline, during treatment (up to 120 weeks)

Phase 2 Stage 1: Number of Participants With Treatment Emergent Adverse Events (TEAEs)

Time frame: From Baseline up to 30 days after the last dose (maximum duration: 414 weeks for Stage 1a and 92 weeks for Stage 1b)

Phase 2 Stage 2: Number of Participants With Treatment Emergent Adverse Events (TEAEs)

AE was defined as any untoward medical occurrence in a participant who received study drug and did not necessarily have to have a causal relationship with the treatment. TEAEs were defined as AEs that developed or worsened during the on-treatment period which was defined as the period from the time of first dose of study treatment until 30 days after the last dose of study treatment.

Time frame: From Baseline up to 30 days after the last dose (maximum duration: 301 weeks)

Phase 2 Stage 1: Duration of Response

DOR:Time from date of 1st IAC determined response (\>= PR) that was subsequently confirmed, to date of first IAC determined PD/death, whichever happened earlier. updated IMWG criteria- PR:\>=50% decrease in difference between involved and uninvolved FLC levels in place of M-protein criteria or a \>=50% reduction in plasma cells in place of M-protein if baseline was ≥30%. If present at baseline a \>=50% reduction in size of soft tissue plasmacytomas; PD: Increase of 25% from lowest response value in any of following: Serum M-protein \>=0.5 g/dL absolute increase and/or urine M-protein \>=200 mg/24 hours absolute increase and/or \>10 mg/dL absolute increase in difference between involved and uninvolved FLC levels, \>=10% bone marrow plasma cells (PCs), development of new bone lesions/soft tissue plasmacytomas or definite increase in size of existing bone lesions/soft tissue plasmacytomas, development of hypercalcemia (corrected serum calcium \>11·5 mg/dl) attributed to PC proliferation disorder.

Time frame: From the date of first response until disease progression or death or data cut-off (maximum duration: 77 weeks for Stage 1a arms and 53 weeks for stage 1b arm)

Phase 2 Stage 2: Duration of Response

DOR: Time from date of 1st IAC determined response (\>= PR) that was subsequently confirmed, to date of 1st IAC determined PD or death, whichever happened earlier. As per updated IMWG criteria-PR: ≥50% reduction of serum M-Protein and reduction in urinary M-protein by ≥90% or to \<200 mg/24 hours. ≥50% decrease in difference between involved and uninvolved FLC levels in place of M-protein criteria or ≥50% reduction in plasma cells in place of M-protein if baseline was ≥30%. If present at baseline ≥50% reduction in size of soft tissue plasmacytomas; PD: Increase of \>25% from lowest response value in any one of following: Serum M-component (absolute increase must be \>0.5 g/dL)4 and/or Urine M-component (absolute increase must be \>200 mg/24 h) and/or \>10 mg/dL absolute increase in difference between involved and uninvolved FLC levels, \>=10% bone marrow plasma cell, development of hypercalcemia (corrected serum calcium \>11.5 mg/dL) attributed solely to plasma cell proliferative disorder.

Time frame: From the date of first response until disease progression or death or data cut-off (maximum duration: 97 weeks)

Phase 2 Stage 1: Percentage of Participants With Clinical Benefit

Clinical benefit: participants with sCR, CR, VGPR, PR or MR as per IMWG criteria, determined by IAC. CR: negative immunofixation on serum \& urine, disappearance of any soft tissue plasmacytomas,\<5% PCs in bone marrow aspirates. sCR: CR + normal FLC ratio (0.26-1.65), absence of clonal cells in bone marrow biopsy. VGPR: serum \& urine M-component detectable by immunofixation, not on electrophoresis/,\>=90% reduction in serum M-component plus urine M-component level \<100mg/24hours; PR: ≥50% reduction of serum M-Protein and reduction in urinary M-protein by ≥90% or to \<200 mg/24 hours, ≥50% decrease in the difference between involved and uninvolved FLC levels in place of the M-protein criteria or a ≥50% reduction in plasma cells in place of M-protein if baseline was ≥30%. If present at baseline, ≥50% size reduction in soft tissue plasmacytomas. MR:\>=25 but \<49% reduction in serum M-protein, reduction in 24h urine M-protein by 50-89%, 25-49% size reduction in soft tissue plasmacytomas.

Time frame: From the date of randomization to the date of first documentation of progression or death (maximum duration: 77 weeks for Stage 1a arms and 53 weeks for stage 1b arm)

Phase 2 Stage 2: Percentage of Participants With Clinical Benefit

Clinical benefit:participants with sCR, CR, VGPR, PR or MR, per IMWG criteria, determined by IAC. CR:negative immunofixation on serum \& urine, disappearance of any soft tissue plasmacytomas,\<5% plasma cells in bone marrow aspirates,normal FLC ratio(0.26-1.65) in participants with only FLC disease.sCR:CR+normal FLC ratio, absence of clonal cells in bone marrow biopsy.VGPR:serum \& urine M-component detectable by immunofixation, not on electrophoresis/,\>=90% reduction in serum M-component plus urine M-component level \<100mg/24h/,\>=90% decrease in difference between involved and uninvolved FLC levels; PR:\>=50% reduction of serum M-protein, reduction in 24h urinary M-protein by \>=90%/\<200mg/24h,\>50% decrease in difference between involved and uninvolved FLC in place of M-protein criteria, \>=50% reduction in size/number of soft tissue plasmacytomas. MR:\>=25 but \<49% reduction in serum M-protein,reduction in 24h urine M-protein by 50-89%, 25-49% reduction in size of soft tissue plasmacytomas

Time frame: From the date of randomization to the date of first documentation of progression or death (maximum duration: 97 weeks )

Phase 2 Stage 1: Progression Free Survival (PFS)

PFS was defined as the time interval from the date of first isatuximab administration to the date of the first IAC-confirmed disease progression (PD) or date of death due to any cause, whichever came first. As per IMWG criteria, PD: Increase of \> 25% from lowest response value in any one or more of the following: Serum M-component and/or (the absolute increase must be \> 0.5 g/dL), Urine M-component and/or (the absolute increase must be \> 200 mg/24 h), \> 10mg/dL decrease in the difference between involved and uninvolved FLC levels in place of the M-protein criteria, \>10% absolute percentage of bone marrow plasma cell, definite development of new bone lesions or soft tissue plasmacytomas or definite increase in the size of existing bone lesions or soft tissue plasmacytomas, development of hypercalcemia (corrected serum calcium \> 11.5 mg/dL or 2.65 mmol/L) that attributed solely to the plasma cell proliferative disorder. Analysis was performed by Kaplan-Meier method.

Time frame: From the date of the first dose administration until progression or death, whichever occurred first (maximum duration: 77 weeks for Stage 1a arms and 53 weeks for stage 1b arm)

Phase 2 Stage 2: Progression Free Survival

PFS was defined as the time interval from the date of first isatuximab administration to the date of the first IAC-confirmed disease progression or the date of death due to any cause, whichever came first. As per IMWG criteria, PD: Increase of \>25% from lowest response value in any one of the following: Serum M-component (the absolute increase must be \>0.5 g/dL)4 and/or Urine M-component (the absolute increase must be \>200 mg/24 h) and/or \>10 mg/dL decrease in the difference between involved and uninvolved FLC levels in place of the M-protein criteria, ≥10% bone marrow plasma cell, development of hypercalcemia (corrected serum calcium \>11.5 mg/dL) attributed solely to the plasma cell proliferative disorder. Analysis was performed by Kaplan-Meier method.

Time frame: From the date of the first dose administration until progression or death, whichever occurred first (maximum duration: 97 weeks)

Phase 2 Stage 1: Change From Baseline in Health Related Quality of Life (HRQL) European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) Scores: Global Health Status

EORTC-QLQ-C30 is a cancer-specific instrument with 30 questions for evaluation of new chemotherapy and provides an assessment of participant reported outcome dimensions. First 28 questions used 4-point scale (1=not at all,2=a little,3=quite a bit,4=very much) for evaluating 5 functional scales (physical, role, emotional, cognitive, social), 3 symptom scales (fatigue, nausea/vomiting, pain) \& other single items. For each item, high score = high level of symptomatology/problem. Last 2 questions represented participant's assessment of overall health \& quality of life, coded on 7-point scale (1=very poor to 7=excellent). EORTC QLQ-C30 observed values and change from baseline for global health status (scoring of questions 29 \& 30) and 5 functional scales, 3 symptom scales and other single items (scoring of questions 1 to 28). Answers were converted into grading scale, with values between 0 and 100. A high score represented a favorable outcome with a best quality of life for participant.

Time frame: Baseline, Day 1 of Cycles 2, 3, 4, 5, 6, 7, 8, 9, 10 and End of Treatment (EOT: anytime up to 77 weeks for Stage 1a arms and 53 weeks for stage 1b arm)

Phase 2 Stage 1: Change From Baseline in European Organization for Research and Treatment of Cancer Quality of Life Multiple Myeloma Specific Module With 20 Items (EORTC QLQ-MY20) Scores: Disease Symptom Subscale Score

EORTC QLQ-MY20 is a validated questionnaire to assess the overall quality of life in participants with MM. It has 4 subscales: body image, future perspective), and 2 symptoms scales (disease symptoms and side-effects of treatment). Disease symptoms subscale used 4-point scale ranged from 1= 'Not at All' to 4= 'Very Much'. Scores were averaged, and transformed to 0 -100 scale, where higher scores = more symptoms and lower health-related quality of life (HRQL) and lower score = less symptoms and more HRQL.

Time frame: Baseline, Day 1 of Cycles 2, 3, 4, 5, 6, 7, 8, 9, 10 and EOT (anytime up to 77 weeks for Stage 1a arms and 53 weeks for stage 1b arm)

Phase 2 Stage 1: Change From Baseline in Euro Quality of Life 5 Dimension (EQ-5D) Generic Health Status - Visual Analogue Scale Scores

EQ-5D was a standardized HRQL questionnaire consisting of EQ-5D descriptive system and Visual Analogue Scale (VAS). EQ-5D VAS was used to record a participant's rating for his/her current health-related quality of life state and captured on a vertical VAS (0-100), where 0 = worst imaginable health state and 100 = best imaginable health state.

Time frame: Baseline, Day 1 of Cycles 4, 7, 10, 13, 16, 19, and EOT (anytime up to 77 weeks for Stage 1a arms and 53 weeks for stage 1b arm)

Pharmacokinetic Assessment: Phase 2 Stage 2: Accumulation Ratio of Isatuximab Based on Ctrough

Ctrough is the plasma concentration observed before treatment administration. For 1st category, the accumulation ratio was calculated by dividing Ctrough value of Cycle 2 Day 1 by Cycle 1 Day 8 and for second category, accumulation ratio was calculated by dividing Ctrough value of Cycle 4 Day 1 by Cycle 1 Day 8.

Time frame: Cycle 2, Day 1; Cycle 1, Day 8; Cycle 4, Day 1

Immunogenicity Assessment: Phase 2 Stage 2: Number of Participants With Anti-drug Antibodies to Isatuximab

ADA response was categorized as: treatment induced and treatment boosted response. Treatment-induced ADA was defined as ADA that developed at any time during the ADA on-study observation period (defined as the time from the first isatuximab administration until end of Phase 2 Stage 2) in participants without preexisting ADA (defined as: ADA that were present in samples drawn before treatment), including participants without pre-treatment (before treatment) samples. Treatment boosted ADA was defined as pre-existing ADA that increased at least 2 titer steps between pre-treatment (before treatment) and post-treatment.

Time frame: Up to 97 weeks