Blinatumomab Versus Standard of Care Chemotherapy in Patients With Relapsed or Refractory Acute Lymphoblastic Leukemia (ALL)

Study Overview
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Brief Summary
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The primary objective was to evaluate the effect of blinatumomab on overall survival when compared to standard of care (SOC) chemotherapy.

Detailed Description
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Adults with relapsed/refractory B-cell precursor ALL were randomized in a 2:1 ratio to receive blinatumomab or 1 of 4 pre-specified, investigator-chosen, SOC chemotherapy regimens. Randomization was stratified by age (< 35 years vs ≥ 35 years of age), prior salvage therapy (yes vs no), and prior allogeneic HSCT (yes vs no) as assessed at the time of consent. The study consisted of up to a 3-week screening and pre-phase period, a treatment period consisting of induction with 2 cycles of either blinatumomab or SOC chemotherapy, a consolidation phase of up to 3 additional cycles of protocol-specified therapy, and a maintenance phase for up to an additional 12 months with protocol-specified therapy. A safety follow-up visit 30 days after the last dose of protocol-specified therapy and a long-term follow-up period were included. The long-term follow-up part of the study was discontinued prematurely based on a recommendation from the data monitoring committee (DMC) that the study be stopped for benefit.

Official Title
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A Phase 3, Randomized, Open Label Study Investigating the Efficacy of the BiTE Antibody Blinatumomab Versus Standard of Care Chemotherapy in Adult Subjects With Relapsed/Refractory B-precursor Acute Lymphoblastic Leukemia (ALL) (TOWER Study)

Conditions
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Relapsed/Refractory B-precursor Acute Lymphoblastic Leukemia

Intervention / Treatment
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* Drug: Blinatumomab
* Drug: Standard of Care Chemotherapy


Participation Criteria
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Eligibility Criteria
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Subjects with Philadelphia negative B-precursor ALL, with any of the following: refractory to primary induction therapy or refractory to salvage therapy, in untreated first relapse with first remission duration <12 months in untreated second or greater relapse relapse at any time after allogeneic HSCT Subject has received intensive combination chemotherapy for the treatment of ALL for initial treatment or subsequent salvage therapy. Greater than 5% blasts in the bone marrow Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 Exclusion Criteria Malignancy other than ALL within 5 years before blinatumomab treatment, except for adequately treated selected cancers without evidence of disease Diagnosis of Burkitt's leukemia according to World Health Organization classification, or human immunodeficiency virus (HIV), Hepatitis B or C, or other clinically significant disorder Current relevant central nervous system (CNS) pathology or known or suspected CNS involvement Isolated extramedullary disease Current autoimmune disease or history of autoimmune disease with potential CNS involvement Autologous HSCT within 6 weeks or allogeneic HSCT within 12 weeks before blinatumomab treatment, or eligibility for allogeneic HSCT at the time of enrollment Active acute grade 2 to 4 graft versus host disease (GvHD) according to Glucksberg et al (1974) criteria that required systemic treatment to prevent or treat GvHD 2 weeks before blinatumomab treatment Known exclusion criteria to investigator choice of SOC chemotherapy (per package insert) Cancer chemotherapy or radiotherapy with 2 weeks, or immunotherapy (included CD19 therapy) within 4 weeks of protocol-specified therapy Abnormal laboratory values (alanine or aspartate transaminase [ALT or AST] or alkaline phosphatase [ALP] ≥ 5 × upper limit of normal [ULN]; total bilirubin or creatinine ≥ 1.5 × ULN), or calculated creatinine clearance < 60 mL/min.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Blinatumomab<br>Participants received blinatumomab by continuous intravenous infusion (CIVI) over 4 weeks followed by a 2 week treatment-free interval for 2 induction cycles. Participants who achieved a bone marrow response, complete remission, or complete remission with partial or incomplete hematologic recovery (CR/CRh*/CRi) within 2 induction cycles of treatment could receive up to 3 additional consolidation cycles of blinatumomab. Participants who received 2 induction and up to 3 consolidation cycles of therapy and continued to have a bone marrow response or CR/CRh*/CRi could continue to receive blinatumomab for an additional 12 months (4 cycles), where 1 cycle consisted of 4 weeks of CIVI followed by an 8-week treatment-free period. The initial dose of blinatumomab was 9 μg/day for the first 7 days of treatment, increased to 28 μg/day starting on day 8 through day 29 and for all subsequent cycles. | Drug: Blinatumomab<br>* Blinatumomab is administered as a continuous intravenous infusion (CIV).<br>* Other names: MT103;|
| Active Comparator: Standard of Care Chemotherapy<br>Participants received one of four prespecified, investigator-chosen chemotherapy regimens for 2 induction cycles. Participants who achieved a bone marrow response, CR/CRh*/CRi within 2 induction cycles of treatment could receive up to 3 additional consolidation cycles of SOC chemotherapy. Participants who received 2 induction and up to 3 consolidation cycles of therapy and continued to have a bone marrow response or CR/CRh*/CRi could continue to receive SOC therapy for an additional 12 months. | Drug: Standard of Care Chemotherapy<br>* FLAG (fludarabine, cytarabine arabinoside, and granulocyte colony-stimulating factor) ± anthracycline-based regimen (e.g. idarubicin 10 mg/m² days 1 & 3; fludarabine 30 mg/m² days 1-5; cytarabine arabinoside 2 g/m² days 1-5). Patients > 60 years: Idarubicin 5 mg/m² day 1 & 3; fludarabine 20 mg/m² day 1-5; cytarabine arabinoside 1 g/m² day 1-5 HiDAC (high-dose cytarabine arabinoside) - based regimen ≥1 g/m²/day ± anthracycline and/or in combination with other drugs such as native Escherichia coli asparaginase, polyethylene glycol linked to asparaginase (PEG-asparaginase), vinca alkaloids, steroids, etoposide or alkylating agents High-dose methotrexate-based regimen (HDMTX; 500 mg/m² to 3 g/m² infused up to 24 hours) in combination with native E. coli asparaginase, PEG-asparaginase, vinca alkaloids, steroids, etoposide or alkylating agents. Clofarabine as a single agent as recommended in the prescribing information or clofarabine-based regimens with 20 mg/m²/day for up to 5 days.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Survival | Overall survival (OS) was calculated from time of randomization until death due to any cause. Participants still alive were censored at the date they were last known to be alive. | From randomization until the data cut-off date of 04 January 2016; median observation time was 11.8 months in the SOC group and 11.7 months in the blinatumomab group. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Complete Remission Within 12 Weeks of Treatment Initiation | Participants were evaluated for efficacy at the end of each treatment cycle via a central bone marrow aspiration and local peripheral blood counts. Complete Remission (CR) was defined as having ≤ 5% blasts in the bone marrow, no evidence of disease, and full recovery of peripheral blood counts: platelets > 100,000/μl, and absolute neutrophil count (ANC) > 1,000/μl. CR must have occurred within 12 weeks of the first dose of therapy. | 12 weeks | 
| Percentage of Participants With Complete Remission/Complete Remission With Partial Hematological Recovery/Complete Remission With Incomplete Hematological Recovery (CR/CRh*/CRi) Within 12 Weeks of Treatment Initiation | Participants were evaluated for efficacy at the end of each treatment cycle via a central bone marrow aspiration and local peripheral blood counts. Complete remission was defined as having ≤ 5% blasts in the bone marrow, no evidence of disease, and full recovery of peripheral blood counts: platelets > 100,000/μl, and ANC > 1,000/μl. Complete Remission with partial hematological recovery (CRh*) was defined as ≤ 5% blasts in the bone marrow, no evidence of disease and partial recovery of peripheral blood counts: platelets > 50,000/μl, and ANC > 500/μl. Complete remission with incomplete hematological recovery (CRi) was defined as ≤ 5% blasts in the bone marrow, no evidence of disease and incomplete recovery of peripheral blood counts: platelets > 100,000/μl or ANC > 1000 (but not both). | 12 weeks | 
| Event Free Survival (EFS) | Event free survival was defined as the time from randomization until a documented relapse after achieving CR/CRh*/CRi or death, whichever occurred first. Participants who failed to achieve a CR/CRh*/CRi within 12 weeks of treatment initiation were considered as non-responders and assigned an EFS duration of 1 day. Participants still alive and relapse-free were censored on their last disease assessment date. A relapse event was any one of the following: Hematological relapse: proportion of blasts in bone marrow >5% or blasts in peripheral blood after documented CR or CRh* or CRi Progressive disease: An increase from baseline of at least 25% of bone marrow blasts or an absolute increase of at least 5,000 cells/μL in the number of circulating leukemia cells Extramedullary relapse: extramedullary lesion that is new or increased by 50% from nadir as assessed by Cheson criteria. The Kaplan-Meier estimate of EFS at 6 months is reported. | 6 months | 
| Duration of Complete Remission | Duration of complete remission, calculated only for participants who achieved a CR, was calculated from the date a CR was first achieved until the earliest date of a disease assessment indicating a relapse event or death, whichever occurred first. Participants who did not have a relapse event were censored on their last disease assessment date. | Up to the data cut-off date of 04 January 2016; median observation time was 10.8 months in the SOC group and 7.0 months in the blinatumomab group. | 
| Duration of Complete Remission/Complete Remission With Partial Hematological Recovery/Complete Remission With Incomplete Hematological Recovery (CR/CRh*/CRi) | Duration of CR/CRh*/CRi, calculated only for participants who achieved a CR/CRh*/CRi, was calculated from the date a CR/CRh*/CRi was first achieved until the earliest date of a disease assessment indicating a relapse event or death, whichever occurred first. Participants who did not have a relapse event were censored on their last disease assessment date. | Up to the data cut-off date of 04 January 2016; median observation time was 10.8 months in the SOC group and 7.2 months in the blinatumomab group. | 
| Percentage of Participants With Minimal Residual Disease (MRD) Within 12 Weeks of Treatment Initiation | Bone marrow samples were evaluated for MRD remission by a central laboratory. MRD remission was defined as the occurrence of an MRD level below 10^-4 measured by quantitative reverse transcription polymerase chain reaction (PCR) or flow cytometry. | 12 weeks | 
| Percentage of Participants Who Received an Allogeneic Hematopoietic Stem Cell Transplant (HSCT) |  | Up to the data cut-off date of 04 January 2016; maximum time on study was 23 months. | 
| Number of Participants With Adverse Events | Adverse events (AEs) were graded for severity according to the CTCAE version 4.0, where Grade 1: Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated. Grade 2: Moderate; minimal, local or noninvasive intervention indicated; limiting age-appropriate instrumental activities of daily living. Grade 3: Severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care activities of daily living. Grade 4: Life-threatening consequences; urgent intervention indicated. Grade 5: Death related to AE. Treatment-related adverse events (TRAEs) were those assessed by the investigator as possibly related to blinatumomab based on response to the question: Is there a reasonable possibility that the event may have been caused by blinatumomab or other protocol-specified therapies/procedures? | From first dose of protocol-specified therapy until 30 days after the last dose, up to the data cut-off date of 04 January 2016; median duration of treatment was 5 days in the SOC group and 70 days in the blinatumomab group. | 
| 100-Day Mortality After Allogeneic Hematopoietic Stem Cell Transplant | The analysis of 100-day mortality after allogeneic HSCT was assessed for participants who achieved a best response of CR/CRh*CTi within 12 weeks of treatment initiation, who received an allogeneic HSCT and did not receive any additional anticancer treatment before the transplant. 100-day mortality after allogeneic HSCT was calculated relative to the date of allogeneic HSCT. The 100-day mortality rate after allogeneic HSCT was defined as the percentage of participants having died up to 100 days after allogeneic HSCT estimated using the estimated time to death in percent calculated by Kaplan-Meier methods. Participants alive were censored on the last documented visit date or the date of the last phone contact when the patient was last known to have been alive. | 100 days, from the date of allogeneic HSCT until the data cut-off date of 04 January 2016 | 
| Number of Participants With Anti-blinatumomab Antibodies | Anti-blinatumomab binding antibodies were evaluated using a validated electrochemiluminescence (ECL)-based assay (binding assay). Samples positive for binding were analyzed using a cell-based bioassay to determine if the detected antibodies had neutralizing properties (neutralizing assay). | Samples were collected on day 29 at the end of cycle 2 and 30 days after the last dose of blinatumomab (median duration of treatment was 70 days). | 
| Time to a 10-point Decrease From Baseline in Global Health Status and Quality of Life or Death | The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) is a 30-item questionnaire that assesses the health related quality of life of cancer patients. The EORTC QLQ-C30 consists of a global health status/quality of life (QoL) scale, 5 functional scales, 3 symptom scales, and 6 single items. The global health/QoL scale consists of 2 questions that ask participants to rate their overall health and overall quality of life durig the past week on a scale from 1 (very poor) to 7 (excellent). The scale score was derived as the sum of each score and transformed to a scale from 0 to 100 where higher scores represent a high QoL. Time to a ≥10-point decrease from baseline GHS/QoL or death, whichever came first, was calculated from baseline. Participants still alive and without a 10-point decrease in GHS/QoL EORTC QLQ-C30 were censored on their last EORTC QLQ-C30 assessment date. | From randomization until the data cut-off date of 04 January 2016; EORTC QLQ-C30 was assessed on day 1, 8, 15, and 29 during cycle 1; days 1, 15, and 29 in cycle 2 and each consolidation cycle, and 30-days following the last dose of drug treatment. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Relapsed; Refractory; B-precursor; Acute Lymphoblastic Leukemia; Philadelphia Negative; ALL; Blinatumomab; Leukemia; Standard of Care; SOC