Purine Analog-Based Conditioning in Patients With Severe Aplastic Anemia

Inclusion Criteria

• Patients up to 70 years of age with a diagnosis of severe AA (Camitta et al., 1979) and a matched unrelated donor who are unresponsive to IS or who have relapsed after an initial response to IS. Patients with a diagnosis of SAA and an human leukocyte antigen (HLA) - compatible sibling donor are eligible only if they are 40 years of age or older (up to age 70) and regardless whether they have received IS or not. Patients with primary or secondary graft failure following autologous or allogeneic stem cell transplant are eligible.
• Patients must have a serum bilirubin of 2 mg/dl or less, serum creatinine 12 weeks). Left ventricular ejection fraction > 40%, no uncontrolled arrhythmia or symptomatic cardiac disease. Forced Expiratory Volume in 1 Second (FEV1), Forced Vital Capacity (FVC) and Carbon Monoxide Diffusing Capacity (DLCO) > 40%. No symptomatic pulmonary disease. Negative pregnancy test.
• Patients must have an HLA-compatible related or unrelated donor willing to donate marrow or rhG-CSF-mobilized peripheral blood stem cells. In the event of transplants from matched unrelated donors, a high-resolution allele match for HLA-A, -B, -C, -DRB1 and DQB1 ("10 of 10 match") is preferred. However, a one-antigen mismatch ("micromismatch") is also considered acceptable matching ("9 of 10 match").
• Patients must sign informed consent. In the event of a pediatric patient (i.e., a minor), consent will be provided by their guardian/parent.
• Lack of clonal cytogenetic abnormalities associated with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) or other hematologic malignancies.

Exclusion Criteria

• Life expectancy of less than 8 weeks. Inability to provide informed consent.