The purpose of this study is to evaluate the serum asparaginase activity in subjects ages 18 to <40 years with ALL or LBL who have developed a hypersensitivity to native E. coli asparaginase or pegaspargase.

Inclusion Criteria:

1. Have a diagnosis of ALL or LBL

2. Be 18 to <40 years of age at the time of enrollment

3. Have a documented ≥ Grade 2 clinical hypersensitivity reaction to native E. coli asparaginase (e.g., Elspar or Kidrolase) or pegaspargase (Oncaspar)

4. Have the following asparaginase doses remaining in their treatment plan:

   • At least two (2) consecutive weeks of native E. coli asparaginase treatment OR
   • At least one (1) dose of pegaspargase (Oncaspar)

5. Have a direct bilirubin ≤ Grade 2 (<3.0 mg/dL [52 µmol/L])

6. Have amylase and lipase within normal limits (per institutional standards)

7. Have a serum asparaginase activity below the detectable limit during screening prior to the first dose of study drug (Erwinaze)

8. Consent to use a medically acceptable method of contraception throughout the entire study period and for 4 weeks after the study is completed. Medically acceptable methods of contraception that may be used by the subject and/or the partner include abstinence, birth control pills or patches, diaphragm and spermicide, condom and vaginal spermicide, surgical sterilization, postmenopausal, vasectomy (>6 months prior to baseline), and progestin implant or injection.

9. Have signed informed consent

Exclusion Criteria:

1. Prior history of ≥ Grade 3 pancreatitis
2. Prior history of a major thrombotic event as assessed by the investigator, or any subject with a history of asparaginase-associated serious hemorrhagic or thrombotic event requiring prolonged anticoagulation therapy with agents such as heparin
3. Prior treatment with Erwinaze
4. Pregnant or lactating female subjects or female subjects of childbearing potential not willing to use an adequate method of birth control (listed above) for the duration of the study
5. Subjects with a history of human immunodeficiency virus (HIV) or hepatitis.
6. Any other condition that would cause a risk (in the investigator's judgment) to subjects if they participate in the trial