| Exclusion Criteria: | 1) Isolated extramedullary relapse (ie, testicular or CNS);
2) Burkitt's or mixed lineage leukemia;
3) Active central nervous system (CNS) leukemia, as defined by unequivocal morphologic evidence of lymphoblasts in the cerebrospinal fluid (CSF), use of CNS-directed local treatment for active disease within the prior 28 days, symptomatic CNS leukemia (ie, cranial nerve palsies or other significant neurologic dysfunction) within 28 days. Prophylactic intrathecal medication is not a reason for exclusion;
4) Prior chemotherapy within </=2 weeks before randomization with the following exceptions: steroids, hydroxyurea, oral mercaptopurine, methotrexate, vincristine, thioguanine, and tyrosine kinase inhibitors are permitted within 2 weeks of randomization as maintenance or to reduce the peripheral blood blast count. Patients must have recovered from acute non hematologic toxicity (to </= Grade 1) of all previous therapy prior to enrollment;
5) Prior monoclonal antibodies within 6 weeks of randomization;
6) Prior allogeneic hematopoietic stem cell transplant (HSCT) or other anti-CD22 immunotherapy </=4 months before randomization. Patients must have completed immunosuppression therapy for treatment of GvHD prior to enrollment. At randomization, patients must not have >/= Grade 2 acute GvHD, or extensive chronic GvHD;
7) Peripheral absolute lymphoblast count >/=10,000 /muL (treatment with hydroxyurea and/or steroids is permitted within 2 weeks of randomization to reduce the WBC count);
8) Known systemic vasculitides (eg, Wegener's granulomatosis, polyarteritis nodosa, systemic lupus erythematosus), primary or secondary immunodeficiency (such as HIV infection or severe inflammatory disease);
9) Current or chronic hepatitis B or C infection as evidenced by hepatitis B surface antigen and anti-hepatitis C antibody positivity, respectively, or known seropositivity for human immunodeficiency virus (HIV). HIV testing may need to be performed in accordance with local regulations or local practice;
10) Major surgery within </=4 weeks before randomization;
11) Unstable or severe uncontrolled medical condition (eg, unstable cardiac function or unstable pulmonary condition);
12) Concurrent active malignancy other than non-melanoma skin cancer, carcinoma in situ of the cervix, or localized prostate cancer that has been definitely treated with radiation or surgery. Patients with previous malignancies are eligible provided that they have been disease free for >/=2 years;
13) Cardiac function, as measured by left ventricular ejection fraction (LVEF) that is less than 45%, or the presence of New York Heart Association (NYHA) stage III or IV congestive heart failure;
14) Patients with active heart disease (NYHA class >/= 3 as assessed by history and physical examination);
15) QTcF > 470 msec (based on the average of 3 consecutive ECGs);
16) Myocardial infarction </=6 months before randomization;
17) History of clinically significant ventricular arrhythmia, or unexplained syncope not believed to be vasovagal in nature, or chronic bradycardic states such as sinoatrial block or higher degrees of AV block unless a permanent pacemaker has been implanted;
18) Uncontrolled electrolyte disorders that can compound the effects of a QTc prolonging drug (eg, hypokalemia, hypocalcemia, hypomagnesemia);
19) History of chronic liver disease (eg, cirrhosis) or suspected alcohol abuse;
20) History of hepatic veno-occlusive disease (VOD) or sinusoidal obstruction syndrome (SOS);
21) Administration of live vaccine </=6 weeks before randomization;
22) Evidence of uncontrolled current serious active infection (including sepsis, bacteremia, fungemia, or patients with a recent history (within 4 months) of deep tissue infections such as fascitis or osteomyelitis;
23) Patients who have had a severe allergic reaction or anaphylactic reaction to any humanized monoclonal antibodies;
24) Pregnant females; breastfeeding females; males and females of childbearing potential not using highly effective contraception or not agreeing to continue highly effective contraception for a minimum of 90 days after the last dose of investigational product;
25) Patients who are investigational site staff members or relatives of those site staff members or patients who are Pfizer employees directly involved in the conduct of the trial;
26) Participation in other investigational studies during active treatment phase;
27) Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the patient inappropriate for entry into this study. |