Phase II Study of the BiTE® Blinatumomab (MT103) in Patients With Minimal Residual Disease of B-precursor Acute Lymphoblastic Leukemia (ALL)

Inclusion Criteria:

* B-precursor ALL patients in complete hematological remission with molecular failure or molecular relapse starting at any time after consolidation I of front-line therapy within German Multicenter Study Group on Adult Acute Lymphoblastic Leukemia (GMALL) standards or at any time outside GMALL standards.
* Patients must have a molecular marker for evaluation of minimal residual disease which is either Breakpoint cluster region/gene on human chromosome #9 (Bcr/abl) at any detection level or individual rearrangements of immunoglobulin or T-cell receptor (TCR)-genes measured by an assay with a sensitivity of minimum 10\^-4: At least one individual marker at a quantitative level ≥ 10\^-4.
* Eastern Cooperative Oncology Group (ECOG) Performance Status \< 2
* Ability to understand and willingness to sign a written informed consent
* Signed and dated written informed consent is available

Exclusion Criteria:

* Current extra medullar involvement
* History of or current relevant central nervous system (CNS) pathology (except migraine/headache and/or previous infiltration of cerebrospinal fluid (CSF) by ALL)
* Current infiltration of cerebrospinal fluid by ALL
* History of or current autoimmune disease
* Autologous stem cell transplantation within 6 weeks prior to study entry
* Any prior allogeneic stem cell transplantation
* Cancer chemotherapy within 4 weeks prior to study treatment (except for intrathecal prophylaxis and/or low dose maintenance therapy such as vinca alkaloids, mercaptopurine, methotrexate, steroids)
* Radiotherapy within 4 weeks prior to study treatment
* Therapy with monoclonal antibodies (Rituximab, MabCampath) within 6 weeks prior to study treatment
* Known hypersensitivity to immunoglobulins or to any other component of the study drug formulation
* Presence of human anti-murine antibodies (HAMA)
* Abnormal bone marrow, renal or hepatic function
* Indication for a hypercoagulative state
* History of malignancy other than ALL within 5 years prior to study entry, with the exception of basal cell carcinoma of the skin or cervix carcinoma in situ
* Active severe infection, any other concurrent disease or medical condition that are deemed to interfere with the conduct of the study as judged by the investigator
* Known infection with human immunodeficiency virus (HIV) or chronic infection with hepatitis B virus (HbsAg positive) or hepatitis C virus (anti-HCV positive)
* Pregnant or nursing women
* Women of childbearing potential not willing to use an effective form of contraception during participation in the study and at least 3 months thereafter or male patients not willing to ensure effective contraception during participation in the study and at least three months thereafter