Inclusion Criteria:

- Patients must be ≥1 and ≤ 21 years of age when originally diagnosed with ALL.

Diagnosis

- Patients must have a diagnosis of acute lymphoblastic leukemia (ALL) with ≥ 25%
blasts in the bone marrow (M3), with or without extramedullary disease.

- Patients may have CNS 1, 2 or 3 disease.

- Karnofsky > 50% for patients > 16 years of age and Lansky > 50% for patients ≤ 16
years of age.

- Prior Therapy

- Patients must have fully recovered from the acute toxic effects of all prior
chemotherapy, immunotherapy, or radiotherapy prior to entering this study.

- Patients must have had 2 or more prior therapeutic attempts defined as:

- Relapse after going into remission from re-induction for the first or subsequent
relapse (ie: 2nd , 3rd, 4th…relapse), OR

- Refractory disease after first or greater relapse and a re-induction attempt, OR

- Failing to go into remission from original diagnosis after 2 previous induction
attempts.

- Hematopoietic Stem Cell Transplant: Patients who have experienced their relapse after
a HSCT are eligible, provided they have no evidence of Graft-versus-Host Disease
(GVHD) and are at least 60 days post-transplant at the time of enrollment.

- Prior anthracycline exposure: Patients must have less than 400 mg/m2 lifetime
exposure of anthracycline chemotherapy. (See Appendix II for calculation worksheet)

- Hematopoietic grow factors: It must have been at least 7 days since the completion of
therapy with GCSF or other growth factors at the time of enrollment. It must have
been at least 14 days since the completion of therapy with pegfilgrastim (Neulasta®).

- Biologic (anti-neoplastic) therapy: It must be at least 7 days after last does of
biologic agent. For agents that have known adverse events occurring beyond 7 days
after administration, this period must be extended beyond the time during which
adverse events are known to occur. The duration of this interval must be discussed
with the study chair

- Monoclonal antibodies: At least 3 half-lives of the antibody must have elapsed after
the last dose of monoclonal antibody. (ie. Rituximab=66 days, Epratuzumab=69 days)

- Immunotherapy: At least 42 days after the completion of any type of immunotherapy,
e.g. tumor vaccines.

Renal and Hepatic Function

- Patient's serum creatinine must be ≤ 1.5 x institutional upper limit of normal (ULN)
according to age. If the serum creatinine is greater than 1.5 times normal, the
patient must have a calculated creatinine clearance or radioisotope GRF ≥
70mL/min/1.73m2.

- Patient's ALT and AST must be < 5 x institutional upper limit of norm ULN. The
hepatic requirements are waived for patients with known or suspected liver
involvement who would otherwise be eligible after consultation with the Study Chair
or Vice Chair.

- Patient's total bilirubin must be ≤ 1.5 x ULN. The hepatic requirements are waived
for patients with known or suspected liver involvement who would otherwise be
eligible.

Cardiac Function:

- Patient must have a shortening fraction ≥ 27% by Echo or an ejection fraction ≥ 50%
by MUGA.

Reproductive Function

- Female patients of childbearing potential must have a negative urine or serum
pregnancy test confirmed prior to enrollment.

- Female patients with infants must agree not to breastfeed their infants while on this
study.

- Male and female patients of child-bearing potential must agree to use an effective
method of contraception approved by the investigator during the study.

Exclusion Criteria:

- Patients will be excluded if they are unable to swallow capsules.

- Patients will be excluded if they are receiving Valproic Acid (VPA) therapy.

- Patients will be excluded if they have a known allergy to any of the drugs used in
the study.

- Patients will be excluded if they have a systemic fungal, bacterial, viral or other
infection that is exhibiting ongoing signs/symptoms related to the infection without
improvement despite appropriate antibiotics or other treatment.

- Patients will be excluded if there is a plan to administer non-protocol chemotherapy,
radiation therapy, or immunotherapy during the study period.

- Patients will be excluded if they have significant concurrent disease, illness,
psychiatric disorder or social issue that would compromise patient safety or
compliance with the protocol treatment or procedures, interfere with consent, study
participation, follow up, or interpretation of study results.

- Patients will be excluded if they have had any positive fungal culture in the last 30
days prior to enrollment.