Critères d'inclusion : - Diagnosis of poor graft function defined as:
* Patient ≥ day+60 after allo-HCT,
* Persisting thrombocytopenia on two different samples over at least two weeks (platelet < 20G/L with transfusion requirement) +/- neutropenia (ANC <1G/L) +/- anemia (Hb <8g/dL or transfusion requirement),
* Full donor chimerism on whole blood (≥ 95%),
* Biopsy proven hypocellular marrow without evidence of myelodysplasia
* No evidence for relapse,
* No evidence for active acute or chronic graft versus host disease,
* Absence of active viral infection (EBV, CMV, ADENOVIRUS, PARVOVIRUS B19),
* Absence of B9/B12 deficiency,
* Absence of hypothyroidism,
* Absence of hypogonadism,
* Absence of dialysis,
* Absence of thrombotic microangiopathy,
* Absence of macrophage activation syndrome,
* No other known causes of poor graft function.
- Written informed consent must be obtained before any study-trial specific procedure are performed,
- Affiliation to a social security system.
Critères de non-inclusion : - Criteria for poor graft function not fulfilled (see above),
- Patients aged less than 6 years old (or unable to swallow),
- Hepatic impairment (Child-Pugh ≥ 5),
- Patients with bone morrow fibrosis,
- Patients with a cytogenetic abnormality of chromosome 7
- Hypersensitivity to eltrombopag or to any of the excipients,
- Patients with any contra-indication to eltrombopag, filgrastim,
- Unable to understand the investigational nature of the study or give informed consent,
- History of congestive heart failure, arrhythmia requiring chronic treatment, arterial or venous,
- Thrombosis (not excluding line thrombosis) within the last 1 year, or myocardial infarction within 3 months before enrollment,
- ECOG Performance Status of 3 or greater,
- Pregnant and/or lactating women,
- Freedom privacy.