Study of US-ATG-F to Prevent Chronic Graft Versus Host Disease (GVHD)

This study is randomized, prospective, double-blind, placebo-controlled, phase 3 study
evaluating the prevention of moderate to severe chronic GVHD in patients undergoing bone
marrow or peripheral blood stem cell transplantation from matched, unrelated donors for acute
leukemia and myelodysplastic syndrome during the first year after transplant.

Patients meeting all the inclusion and none of the exclusion criteria will be randomized
(1:1). All patients will receive premedication and study drug 3 days prior to
transplantation.

Key Inclusion Criteria:

- 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