patients designated to undergo allogeneic peripheral blood or bone marrow stem cell transplantation following the diagnosis of one of the primary diseases in early or intermediate disease status (i.e., acute myeloid leukemia, acute lymphoid leukemia, and myelodysplastic syndrome)

patients with an unrelated hla-a,-b, -c and -drbi matched donor

patients with a karnofsky performance score ≥ 70%

key exclusion criteria:

clinically significant concomitant diseases (i.e., cardiac, pulmonary, renal and cns)

bacterial, viral, or fungal infections

known positive for hepatitis b surfaces antigen, or hepatitis c antibody, or who have been tested positive for hiv

patients with any concurrent malignancy. cancer treated with curative intent < 5 years previously will not be allowed except for patients with resected basal cell carcinoma or treated cervical carcinoma in situ

known contraindications to the administration of rabbit immunoglobulin antibodies

hypersensitivity to methylprednisolone, tacrolimus, methotrexate or any excipients contains in these products