CAT-8015 in Children, Adolescents and Young Adults With Acute Lymphoblastic Leukemia or Non-Hodgkin's Lymphoma

You may be eligible if

• \- Histologically confirmed diagnosis of acute lymphoblastic leukemia (ALL) or non-Hodgkin's lymphoma (NHL) including lymphoblastic lymphoma, Burkitt's lymphoma, and large cell lymphoma; - Measurable or evaluable disease. - Evidence of CD22-positive malignancy by one of the following criteria: - greater than or equal to (\>=) 30 % of malignant cells from a disease site cluster of differentiation 22+ (CD22+) by fluorescence-activated cell sorter (FACS) analysis or; ≥ 15 % of malignant cells from a disease site CD22+ by immunohistochemistry (IHC). Stage of disease: - Participants must have relapsed or refractory disease and have received at least one standard chemotherapy and one salvage regimen or allogeneic stem cell transplant; - Relapse after prior autologous or allogeneic HSCT is allowed. In the event of relapse after prior allogeneic HSCT, the participant must be at least 100 days post-transplant and have no evidence of ongoing active graft-vs-host disease; - Recovered from the acute toxic effects of all prior therapy before entry. Performance status: - Participants greater than or equal to (\>=) 12 years of age: Eastern Cooperative Oncology Group (ECOG) score of 0, 1, 2, or 3; - Participants \< 12 years of age: Lansky scale \>= 50%; - Participants who are unable to walk because of paralysis, but who are up in a wheel chair will be considered ambulatory for the purpose of calculating the performance score. Participants with the following central nervous system (CNS) status, are eligible only in the absence of neurologic symptoms suggestive of CNS leukemia, such as cranial nerve palsy. - Female and male participants with childbearing potential and their sexual partners must agree to use an approved method of contraception during the study.