Monitoring and Treatment of Relapsed Leukemia Following Allogeneic Hematopoietic Stem Cell Transplantation in Children

Patients will be enrolled on this study at the time of transplantation. Following HSCT, CD34+
chimerism in peripheral blood will be monitored in real time at scheduled intervals. If
chimerism of CD34+ cells diminishes post-HSCT or clinical signs or symptoms of relapsed
leukemia, relapse in bone marrow will be confirmed, after which immunosuppression will be
withdrawn and treatment initiated with bortezomib and pravastatin. Patients will be monitored
for disease response until 1 year post-HSCT or post-study therapy. Patients with confirmed
relapse post-HSCT will also be eligible to enroll and receive novel combination.

Inclusion Criteria to enter study:

- Voluntary written informed consent by patient or legal guardian (as appropriate)
before performance of any study-related procedure not part of normal medical care,
with the understanding that consent may be withdrawn by the subject at any time
without prejudice to future medical care

- Female patients who:

- Are postmenopausal for at least 1 year before the Screening visit, OR

- Are surgically sterile, OR

- If they are of childbearing potential, agree to practice 2 effective methods of
contraception, at the same time, from the time of signing the informed consent
through 30 days after the last dose of study treatment, OR agree to completely
abstain from heterosexual intercourse

OR Male patients, even if surgically sterilized (i.e., status postvasectomy), who:

- Agree to practice effective barrier contraception during the entire study treatment
period and through 30 days after the last dose of study treatment, OR

- Agree to completely abstain from heterosexual intercourse

- Lansky(if age <15)/Karnofsky (if age >16 yr) performance status > 50%

- Hepatic function: total bilirubin ≤ 2.5 mg/dl, and ALT/AST < or equal to 5 x the
upper limit of normal

- Renal function: Creatinine clearance > 60 ml/min/1.73 m2 (as determined by 24
hour collection or nuclear (glomerular filtration rate) GFR or Cystatin C
calculation)

- Cardiac function: LVEF > 50% or LVSF > 27%

- Pulmonary function tests: DLCO and FEV1 > 50% (if able to perform PFTs, if not
able to perform PFTs SAO2> 94% on room air).

- Acute leukemia or Myelodysplastic syndrome (MDS)

Inclusion Criteria to initiate therapy with bortezomib and pravastatin

- Lansky performance status (if age < 15) /Karnofsky (if age >16 yr) performance status
> 50%

- Hepatic function: total bilirubin ≤ 2.5 mg/dl, and ALT/AST < or equal to 5 x the upper
limit of normal (ULN)

- Renal function: Cr < ULN for age

- Relapse of systemic disease documented by any of the following: morphology, flow
cytometry, cytogenetics and/or FISH.

- Patient has a platelet count of more than 20,000/μL within 7 days before enrollment.
Patients may be transfused prior to this evaluation but may not be platelet refractory
at enrollment.

- Patient has an absolute neutrophil count of greater than 500 /μL within 7 days before
enrollment.

- Patients with confirmed relapse post-HSCT who were not previously enrolled on
monitoring portion of protocol, will also be eligible to enroll and receive novel
combination if entry criteria met at time of relapse.

Exclusion Criteria:

Patients meeting any of the following exclusion criteria are not to be treated on the
study:

- Patient has greater than or equal to Grade 2 peripheral neuropathy

- Patient had myocardial infarction within 6 months prior to enrollment or has New York
Heart Association (NYHA) Class III or IV heart failure, uncontrolled angina, severe
uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute
ischemia or active conduction system abnormalities. Prior to study entry, any ECG
abnormality at screening must be documented by the investigator as not medically
relevant.

- Patient has hypersensitivity to bortezomib, boron, or mannitol.

- Female patients who are lactating or pregnant.

- Serious medical or psychiatric illness likely to interfere with participation in this
clinical study.

- Evidence of residual or relapse of another malignancy(other than the hematological
malignancy which is the indication for stem cell transplant)at the time of transplant
preparative regimen initiation

- Participation in clinical trials with other investigational agents not included in
this trial, within 14 days of the start of bortezomib/pravastatin and throughout the
duration of therapy.

- Radiation therapy within 3 weeks before start of bortezomib/pravastatin. Enrollment of
subjects who require concurrent radiotherapy (which must be localized in its field
size) should be deferred until the radiotherapy is completed and 3 weeks have elapsed
since the last date of therapy.