Inclusion Criteria:

1. Patients with previously treated Philadelphia-chromosome-negative B-ALL, with
progression after at least one prior therapy. Patients with
Philadelphia-chromosome-positive B-ALL can only be included if they are refractory or
intolerant to at least one tyrosine-kinase-inhibitor.

2. Male or female patients at least 16 years of age; if the patient is less than 18
years of age, the patient must have the ability to understand and give written assent
in addition to the parent's/guardian's written informed consent.

3. Patients with histologically confirmed diagnosis of B-ALL

4. Mixed phenotype acute leukemia patients who have B cell immunophenotype.

5. Patients with a white blood cell count less than 30000/mm3 (Note: This criterion can
be removed if 3 of the first 5 patients show no marked increase in blast count or
tumor lysis syndrome.)

6. Patients with an Eastern Cooperative Oncology Group performance status of less than
or equal to 2

7. Patients with a total bilirubin of less than or equal to 2.0 mg/dL

8. Patients with alanine aminotransferase or aspartate aminotransferase less than or
equal to 2.5 times the upper limit of normal

9. Patients with a creatinine level of less than or equal to 2.0 mg/dL

10. If a female of childbearing potential, confirmation of a negative pregnancy test
before enrollment and use of double-barrier contraception, confirmation of a negative
pregnancy test before enrollment and use of oral contraceptive plus barrier
contraceptive, or confirmation of having undergone clinically documented total
hysterectomy, oophorectomy, or tubal ligation

11. If a male, use of an effective barrier method of contraception during the study and
for 3 months after the last dose if sexually active with a female of childbearing
potential

12. Patients with the ability to understand and give written informed consent and to
comply with the study protocol

Exclusion Criteria:

1. Patients who received previous treatment with an anti-CD19 antibody or fragments

2. Receipt of anti-CD20 therapy no greater than 4 weeks before the first study dose

3. Patients having undergone prior allogeneic stem cell transplantation within 3 months
or having active graft versus host disease

4. Patients with known hypersensitivity to any excipient contained in the drug
formulation

5. Patients with a New York Heart Association Class III or IV

6. History of stroke or myocardial infarction within the last 6 months

7. Patients with a history of positive human immunodeficiency virus test result (ELISA
or western blot)

8. Patients with clinical or laboratory evidence of active hepatitis B (positive
hepatitis B surface antigen with negative hepatitis B surface antibody) or hepatitis
C (positive hepatitis C virus [HCV] antibody and detectable HCV ribonucleic acid with
alanine aminotransferase above normal range)

9. Patients with active viral, bacterial, or systemic fungal infection requiring active
parenteral treatment

10. Patients who are receiving active treatment/chemotherapy for another primary
malignancy within the past 5 years (except ductal breast cancer in situ, for
nonmelanoma skin cancer, prostate cancer not requiring treatment, and cervical
carcinoma in situ)

11. Patients who are pregnant or breastfeeding

12. Patients with major surgery or radiation therapy within 4 weeks prior to first study
dose