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

* 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 blinatumom…