Stem Cell Transplant in Treating Patients With Acute Myeloid Leukemia

OBJECTIVES:

- To assess whether sufficient peripheral blood stem cells (PBSC) can be collected from
patients with acute myeloid leukemia (AML) using cyclophosphamide, etoposide, and
granulocyte-colony stimulating factor (G-CSF) mobilization.

- To assess the rate of myeloid, platelet, and erythroid recovery following autologous
PBSC transplant.

- To assess the disease-free survival rate of patients with AML receiving PBSC auto
grafts.

OUTLINE:

- Chemotherapy and filgrastim (G-CSF) priming for PBSC collection: Patients receive
cyclophosphamide IV on day 0; etoposide IV over 3 hours on days 0 and 1; and oral
dexamethasone twice daily on days 0 and 1. Patients also receive G-CSF subcutaneously
(SC) beginning on day 3 and continuing until apheresis is complete. After blood counts
recover, apheresis is performed in 4-6 daily planned collections until the minimum CD34+
cell dose of > 2.5 x 10^6 cells/kg is achieved. If the minimum CD34+ cell dose is not
achieved after 6 apheresis collections, patients undergo bone marrow examination
including a bone marrow biopsy and aspiration, at the termination of the PBSC collection
to confirm remission. If remission is confirmed, and if peripheral counts and marrow
cellularity are sufficient, the patient remains off G-CSF for 7 days and receives
sargramostim (GM-CSF) for 5 days to increase the marrow cellularity, after which a bone
marrow harvest is performed.

- Bone marrow harvest without prior PBSC collection: Children will undergo primed bone
marrow harvest comprising GM-CSF IV or SC for 5 days prior to harvest to increase
cellularity and then marrow is harvested. Marrow and blood specimens are also obtained
with the initial bone marrow evaluation and at the time of harvest if a cytogenetic
abnormality was previously described. Other patients who are unable to undergo PBSC
collection may proceed with a bone harvest at the discretion of the protocol
chairperson.

- Cytoreductive regimen:

- Patients over 2 years old: Patients undergo total body irradiation (TBI) twice
daily on days -7 to -4 (total of 8 fractions), cyclophosphamide IV over 2 hours on
days -3 and -2, followed by a 1-day rest period on day -1.

- Patients under 2 years old and patients who cannot undergo TBI: Patients receive
busulfan IV or orally every 6 hours on days -7 to -4, cyclophosphamide IV over 2
hours on days -3 to -2, followed by a 1-day rest period on day -1.

- Stem cell transplantation: All patients undergo autologous PBSC and/or bone marrow
infusion on day 0. Patients also receive G-CSF IV or SC beginning on day 1 and
continuing until blood counts recover.

After completion of study treatment, patients are followed periodically for 5 years.

Inclusion Criteria:

Children under the age of two are eligible for this protocol, but will not receive total
body irradiation. Instead, children under the age of two will receive
Busulfan/Cyclophosphamide (Bu/Cy) conditioning as the preparative regimen in order to
obviate deleterious effects of radiation at this age. Patients who cannot receive total
body irradiation (TBI) (for example those with prior radiation therapy) will also receive
the Bu/CY conditioning.

- Acute myeloid leukemia (AML)

- All children and adults less than the age of 70 with AML who have achieved a
first or second bone marrow remission are eligible for this protocol. Patients
must undergo peripheral blood stem cell collection or marrow harvest while in
remission and must not be expected to have better outcomes with allogeneic
transplantation.

- Patients with cytogenetic abnormalities suggesting an improved prognosis
[t(8:21), t(15;17) and inv(16)] will be eligible for transplantation in first
remission.

- Allogeneic transplant with an HLA-identical sibling will be recommended for patients
<55 years. If the patient refuses allogeneic transplant, they may still be eligible
for this protocol.

Exclusion Criteria:

- Patients can also be deemed not eligible for transplant because of specific organ
toxicity. Specifically, patients with pre-existing compromise to the heart, lungs,
kidney, CNS or liver may be excluded:

- Eastern Cooperative Oncology Group (ECOG) Performance status: 0 or 1

- Heart - The patient must be free of symptoms of uncontrolled cardiac disease, and
must not have compromised cardiac function detected by ECHO or by gated cardiac
blood flow scan (MUGA) LVEF >45%).

- Kidney - The patient must have a corrected creatinine clearance >50% of normal.

- Liver - The total serum bilirubin < 2.5 mg/dL; ALT <2 x upper limit of normal.

- Lung - Patients must have no significant obstructive airways disease or resting
hypoxemia (PO2 <80), and must have acceptable diffusion capacity (DLCO > 50% of
predicted).

- Central Nervous System (CNS): Patients must be free of active or ongoing ischemic
or degenerative CNS disease and no active or resistant CNS leukemia.