Cytosine Arabinoside and Mitoxantrone for Patients With Juvenile Myelomonocytic Leukemia Receiving Repeat Stem Cell Transplantation

OBJECTIVES:

Primary

- To determine the incidence of 1-year disease-free survival in patients with juvenile
myelomonocytic leukemia and who is undergoing a repeat stem cell transplantation.

Secondary

- To evaluate the incidence of regimen-related toxicity.

- To evaluate the incidence of acute and chronic graft-versus-host-disease.

- To evaluate the incidence of relapse.

OUTLINE:

- Preparative cytoreductive therapy: Patients receive high-dose cytarabine IV over 2 hours
on days -9 to -4 and mitoxantrone hydrochloride IV over 30 minutes on days -9 to -7.

- Allogeneic hematopoietic stem cell transplantation (HSCT): Patients undergo HSCT on day
0. Patients undergoing umbilical cord blood transplantation receive methylprednisolone
(as graft failure prophylaxis) IV twice daily on days 5 to 19 followed by a taper every
other day thereafter until day 25.

- Graft-versus-host-disease (GVHD) prophylaxis: Patients receive cyclosporine IV over 2
hours every 8-12 hours or orally twice daily beginning on day -3 and continuing until
day 50, followed by a taper to day 90, in the absence of GVHD. Patients undergoing
nongenotypically identical bone marrow transplantation also receive methotrexate IV on
day 1 beginning 24 hours after completion of stem cell infusion and on days 3, 6, and
11.

- Post-transplantation isotretinoin therapy: Patients receive oral isotretinoin once daily
beginning on day 60 and continuing until 1 year after HSCT.

Patients undergo bone marrow sample collection on day 21, day 60, day 100, at 6 months, and
at 1 year for chimerism studies. Patients also undergo blood sample collection periodically
to monitor peripheral blood counts for immune reconstitution.

After completion of study treatment, patients are followed on day 21, day 100, at 6 months,
and at 1 year.

Inclusion Criteria:

- Patients age 0-18 with juvenile myelomonocytic leukemia (JMML) who have relapsed or
have residual disease after allogeneic HCT. Residual disease is defined as failure to
eradicate original disease without prior documentation of remission. Relapse is
defined as reappearance of i) leukocytosis with absolute monocytosis >1 x 10^8/L, ii)
presence of immature myeloid cells in the peripheral circulation in two consecutive
bone marrow specimens taken at least one month apart, or iii) presence of clonal
cytogenetic abnormality. The diagnosis of relapse will be supported by the return of
an abnormal cytogenetic marker (if present at diagnosis) or the presence of host cells
by RFLP or other method.

- Patients should be at least 6 months from first hematopoietic cell transplant (HCT) if
clinically stable. (If JMML is rapidly progressive, second HCT may be performed
earlier).

- Adequate major organ function including:

- Cardiac: ejection fraction ≥45%

- Pulmonary: FEV >50%, DLCO >50%

- Renal: creatinine clearance ≥40 mL/min

- Hepatic: no clinical evidence of hepatic failure (e.g. coagulopathy,
ascites)

- Karnofsky performance status ≥70% or Lansky score ≥50%

- Written informed consent.

Exclusion Criteria:

- Active uncontrolled infection within one week of HCT.