Rescue treatment with eltrombopag in refractory cytopenias after allogeneic stem cell transplantation

Background: Patients with post-transplant cytopenias due to poor graft function or primary engraftment failure show poor prognosis with a high mortality rate mainly because of graftversushost disease (GVHD), infection and/or bleeding. Treatment options are scarce and a CD34+ stem cell boost or a second bone marrow transplantation may be required to restore adequate haematopoiesis. Methods: In the present study patients with primary engraftment failure (n = 1) and refractory poor graft function (n = 11) were treated with eltrombopag in a single centre. The reason for eltrombopag treatment was trilineage cytopenia in six patients, bilineage cytopenia in three patients and single lineage cytopenia in three patients. Eltrombopag was initiated at a median of 214 (range: 120-877) days after haematopoietic stem cell transplantation (HCST) and administered for a median time of 114 (range: 12 days to >490) days. In 8/12 patients eltrombopag was introduced at a dose of 75 mg/day and then increased to 150 mg/day after 1 week; 1 patient was given 50 mg eltrombopag per day, and 3 patients received 75 mg daily. Results: In 10/12 patients eltrombopag significantly enhanced blood count values and patients became transfusion independent. Once stable haematological response was obtained, treatment was tapered until final discontinuation in 9/10 responding patients. No grade 3 or 4 toxicities were observed. At time of last follow up, 3/12 patients were dead, 2 due to disease relapse, 1 due to GVHD and pneumonia. All patients except one maintained their complete response and remain transfusion independent at a median of 858 (range: 429-1119) days. Conclusion: These preliminary data confirm that eltrombopag is able to rescue multilineage haematopoiesis in patients with treatment-refractory cytopenias after allogeneic HSCT.