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

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.

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.

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.

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.

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.

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.

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.

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).

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).

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).

Serum/plasma markers included: tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1-β), interleukin 6 (IL-6) and interferon-gamma (IFN-Gamma). Due to change in planned analysis, data for high-sensitivity C-reactive protein (hs-CRP) and CD38 was not collected and analyzed.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

OS was defined as the time interval from the date of first Isatuximab administration to death from any cause. Analysis was performed by Kaplan-Meier method.

OS was defined as the time interval from the date of first Isatuximab administration to death from any cause. Analysis was performed by Kaplan-Meier method.

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.

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.

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.

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.

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.