In vitro effect of eltrombopag alone and in combination with azacitidine on megakaryopoiesis in patients with myelodysplastic syndrome

Thrombocytopenia is a severe complication for patients with myelodysplastic syndrome (MDS). Eltrombopag increases platelet count in MDS patients but its combination with azacitidine elicited controversial results. We aimed to quantify the colony forming units of megakaryocytes (CFU-Mk) obtained from CD34+ bone marrow cells isolated from patients with MDS and from healthy donors that were cultured in vitro in the presence or absence of azacitidine and with or without the sequential addition of eltrombopag to the culture medium. CD34+ bone marrow cells from 6 MDS patients and 3 controls were expanded in vitro and cultured for 3 days with or without azacitidine. Subsequently, a CFU-Mk assay was performed in presence or absence of eltrombopag. The addition of eltrombopag in the CFU-Mk assay after mock treatment of CD34+ cells increased the number of CFU-Mk in both controls and patients. On the contrary, using azacitidine pretreated CD34+ cells, eltrombopag minimally increased CFU-Mk in controls and produced heterogeneous response in MDS patients with no change in two patients and CFU-Mk increase in four patients. In vitro CFU-Mk assay suggest that some MDS patients are likely to benefit from the sequential addition of eltrombopag after azacitidine treatment, in the context of a personalized medicine

Transcription factors implicated in late megakaryopoiesis as markers of outcome after azacitidine and allogeneic stem cell transplantation in myelodysplastic syndrome

The hypomethylating agent azacitidine (AZA) is used to treat higher-risk myelodysplastic syndromes (HR-MDS) and elderly patients with low-blast count acute myeloid leukemia (LBC-AML). Platelet recovery is an early predictor of AZA response. We prospectively studied the expression profile of transcription factors, critical for late megakaryopoiesis and changes in their expression after AZA treatment in patients with HR-MDS and LBC-AML enrolled in the BMT-AZA trial (EudraCT number 2010-019673-15). Twenty-five additional patients with low-risk (LR)-MDS were also studied.At the time of diagnosis, GATA2 mRNA levels were significantly higher in MDS as compared to controls, with increasing levels from LR- to HR-MDS/AML. RUNX1 expression was also significantly higher in MDS, as compared to controls, but no differences were found between LR- and HR-MDS. Looking at biomarkers of response, we found that patients AZA responsive had higher basal GATA1 and lower FLI1 expression, compared to those with stable or progressive disease after treatment. Univariate analysis showed that increased GATA2 mRNA expression was associated with a worse overall survival. Our findings suggest that high GATA2 expression is a poor prognostic marker for survival in patients with HR-MDS and LBC-AML treated with azacitidine. Moreover, GATA1 and FLI1 mRNA expression may predict response to AZA treatment

In vitro Effect of Eltrombopag Alone and in Combination With Azacitidine on Megakaryopoiesis in Patients With Myelodysplastic Syndrome

Thrombocytopenia is a severe complication for patients with myelodysplastic syndrome (MDS). Eltrombopag increases platelet count in MDS patients but its combination with azacitidine elicited controversial results. We aimed to quantify the colony forming units of megakaryocytes (CFU-Mk) obtained from CD34+ bone marrow cells isolated from patients with MDS and from healthy donors that were cultured in vitro in the presence or absence of azacitidine and with or without the sequential addition of eltrombopag to the culture medium. CD34+ bone marrow cells from 6 MDS patients and 3 controls were expanded in vitro and cultured for 3 days with or without azacitidine. Subsequently, a CFU-Mk assay was performed in presence or absence of eltrombopag. The addition of eltrombopag in the CFU-Mk assay after mock treatment of CD34+ cells increased the number of CFU-Mk in both controls and patients. On the contrary, using azacitidine pretreated CD34+ cells, eltrombopag minimally increased CFU-Mk in controls and produced heterogeneous response in MDS patients with no change in two patients and CFU-Mk increase in four patients. In vitro CFU-Mk assay suggest that some MDS patients are likely to benefit from the sequential addition of eltrombopag after azacitidine treatment, in the context of a personalized medicine