Platelet recovery is significantly hampered following umbilical cord blood transplantation (UCB). Thus, after UCB transplantations, patients are platelet transfusion-dependent for prolong periods of time.

Eltrombopag is a thrombopoietin-receptor agonist that initiates thrombopoietin-receptor signaling and thereby induces proliferation and maturation of megakaryocytes.

We will evaluate the safety and efficacy of eltrombopag for enhancing platelet engraftment in pediatric patients undergoing cord blood transplantation.

Inclusion Criteria:

1. Patient ≥ 1 year and < 18 years old.
2. Patients receiving unmanipulated single or double UCB allogeneic grafts.
3. Malignant and non malignant indications for transplantation.
4. Myeloablative and reduced intensity conditioning regimens.
5. Patients must meet all other pre-transplantation criteria of the transplantation center including acceptable tests of heart, liver, kidney, and lung function (standard screening for transplantation per PI, and co-investigators).
6. Written informed must be obtained from the patient's guardian, and accompanying informed assent from the patient for children over 6 years old.
7. Able to comply with study protocol.

Exclusion Criteria:

1. Indications for transplantation

   1. Patients with primary myelofibrosis.
   2. French-American-British classification (FAB)M7 acute myeloid leukemia. Acute leukemia secondary to a myeloproliferative neoplasm.
   3. Patients with persistent acute leukemia (>5% bone marrow blasts) at the time of transplantation.

2. Patients with prior thromboembolic event. Patients with previous catheter related thrombosis will be eligible if more than 3 months elapsed.

3. Hypersensitivity to eltrombopag.

4. Liver enzymes abnormalities:

Alanine aminotransferase (ALT) levels > 3 times the upper limit of normal (ULN) or serum bilirubin > 1.5 ULN (unless due to Gilbert's syndrome or hemolytic bilirubin).

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