Inclusion Criteria:

          1. Pediatric and adult patients with a diagnosis of ALL or LBL.

          2. Have had an allergic reaction to a long-acting E. coli-derived asparaginase OR have
             silent inactivation.

          3. Have 1 or more courses of E. coli-derived asparaginase remaining in his/her treatment
             plan.

          4. Patients must have, in the opinion of the Investigator, fully recovered from their
             prior allergic reaction to E. coli-derived asparaginase.

        Exclusion Criteria:

          1. Have previously received asparaginase Erwinia chrysanthemi or JZP-458.

          2. Have relapsed ALL or LBL.

          3. Are concurrently receiving another investigational agent and/or treated with an
             investigational device at the same time as JZP-458 (within 48 hours) during Course 1
             of JZP-458.

          4. Have a history of ≥ Grade 3 pancreatitis.

          5. Prior history of asparaginase-associated ≥ Grade 3 hemorrhagic event or
             asparaginase-associated thrombus requiring anticoagulation therapy, excluding
             catheter-related thrombotic events.