Phase I/II Study of Moxetumomab

Study Groups:

If you are found to be eligible to take part in this study, you will be assigned to a study
group based on when you join this study. Up to 4 groups of 3-6 participants will be enrolled
in the Phase 1 portion of the study.

If you are in Phase 1, the dose of moxetumomab pasudotox you receive will depend on when you
join the study. The first group will receive the lowest dose level of moxetumomab pasudotox.
Each additional group will receive a higher dose than the previous group, if no intolerable
side effects were seen.

If you are in Phase 2, you will receive the highest dose of moxetumomab pasudotox found to
be safe in the Phase 1 portion of the study.

Study Drug Administration:

You will receive moxetumomab pasudotox by vein on Days 1, 3, 5, 7, 9, and 11 of each 21-day
cycle. You may be treated in the hospital for the first cycle. If your doctor thinks it is
needed, the length of study cycles may be changed.

You may receive drugs to control side effects one hour before your dose of the study drug
and up to 12 hours after your dose of the study drug. You may also receive fluids for
hydration before and after your dose of the study drug.

Study Visits:

Every week during Cycle 1, blood (about 1 tablespoon) will be drawn for routine tests.

Within 1 week before Day 1 of each study cycle:

- You will have a physical exam.

- Blood (about 2 tablespoons) will be drawn for routine tests.

- If your doctor thinks it is needed, you will have an eye exam.

- Blood (about 2 teaspoons) will be drawn to test for drug antibodies.

On Day 1 (1st dose) of Cycle 1, before and right after your first dose of study drug and
then 4-5 more times over the next 8 hours, blood (about 1/2 teaspoons each time) will be
drawn for pharmacokinetic (PK) testing. PK testing measures the amount of study drug in the
body at different time points. At the 6th dose, blood (about 1/2 teaspoon each time) will be
drawn before and right after your dose of study drug for PK testing. PK testing for the 1st
and 6th dose will be repeated for Cycle 2 and every 4th treatment cycle until the end of
treatment.

If the doctor thinks the disease is responding to the study drug, blood (about 1 tablespoon)
will be drawn at least 1 time every week for routine tests.

Between Days 14-21 (+/- 7 days) of Cycle 1, you will have a bone marrow biopsy/aspiration.
You will have additional bone marrow biopsy/aspirations every 2-4 cycles after that, and
then every 3 months for up to 1 year during the follow-up period.

At the end of each cycle, urine will be collected for routine tests.

After your last dose of study drug, blood (about 2 teaspoons) will be drawn to test for drug
antibodies.

Length of Study:

You may continue taking the study drug for as long as the doctor thinks it is in your best
interest. If your doctor thinks the disease is responding, you may receive up to 6 cycles.
You will no longer be able to take the study drug if the disease gets worse, if intolerable
side effects occur, or if you are unable to follow study directions.

Your participation on the study will be over after the follow-up visits.

Follow-Up Visit:

About 30 days after the last dose of the study drug, you will be asked to return to the
clinic for follow-up tests. During this visit, you may have blood drawn and other tests
performed to check the status of the disease, to test for drug antibodies, and to check your
health.

If you cannot come to MD Anderson, you will be contacted by phone and asked about your
health.

This is an investigational study. Moxetumomab pasudotox is not FDA approved or commercially
available. At this time, it is being used for research purposes only.

Up to 60 patients will take part in the study. All will be enrolled at MD Anderson.

Inclusion Criteria:

1. Patients age 18 years or older with previously treated ALL (relapsed and/or
refractory after prior therapy); patients with relapsed/refractory biphenotypic
leukemia expressing the appropriate antigen (CD22) are also eligible to participate,
Pediatric patients younger than 18 may be considered with sponsor approval once the
MTD has been established in the adult population.

2. ECOG Performance status 0-2.

3. Adequate liver function (bilirubin less than or equal to 1.5 mg/dL and SGPT or SGOT
less than or equal 2.5 x upper limit of normal [ULN], unless considered due to tumor
or hemolysis), and renal function ( Calculated CrCl of greater than or equal to 50 or
serum creatinine less than 2 x ULN.) Even if organ function abnormalities are
considered due to tumor, the upper limit for bilirubin is less than or equal to 2.0
mg/dL (unless due to hemolysis or Gilbert's disease, i.e. mainly indirect bilirubin)
and creatinine less than or equal 2 mg/dL

4. Provision of written informed consent.

Exclusion Criteria:

1. Patient with active heart disease (NYHA class greater than or equal to 2 as assessed
by history and physical examination).

2. Patients with a cardiac ejection fraction (as measured by either MUGA or
echocardiogram) less than 40%

3. Patients with active hepatitis

4. Pregnant or breast-feeding women. Women of childbearing potential must have a
negative urine or serum pregnancy test within 14 days of start of treatment.

5. prior radioimmunotherapy within 3 years of enrollment

6. serum albumin less than 2g/dL

7. oxygen saturation at rest by pulse oximetry less than 88% or PaO2 less than or equal
to 55mm Hg

8. history of microangiopathic hemolysis, TTP or HUS.

9. symptomatic CNS involvement

10. Less than 100 days post -transplant or any evidence of active GVHD

11. systemic chemotherapy less than 14 days prior; however treatment may start earlier if
there is evidence of rapidly progressive disease if approved by the Principal
Investigator

12. monoclonal antibody therapy less than 1 month

13. investigational agents within 28 days of dosing; however treatment may start earlier
if there is evidence of rapidly progressive disease if approved by the Principal
Investigator

14. HIV+/AIDS

15. history of exposure to pseudomonas exotoxin containing molecule

16. Patients with active lung infection or active pulmonary edema.

17. Patients with laboratory findings consistent with Grade equal to greater than 3
disseminated intravascular coagulation (DIC) or any Grade 2 DIC that does not
correct.

18. Patients with clinically significant ophthalmologic findings (as determined by an
ophthalmologist) during screening should be excluded from the trial

19. Pre-treatment greater than QTc interval of 490 ms