Platelet activation and function during eltrombopag treatment in immune thrombocytopenia.

We monitored platelet activation by means of P-selectin and platelet monocyte aggregates (PMA) and platelet function by whole blood multiple electrode aggregometry and platelet adhesion under high shear in chronic immune thrombocytopenia patients to define changes in platelet activation during treatment with eltrombopag. Overall, platelet activation and function normalized with increasing platelet counts. However, P-selectin, which was already elevated before treatment, and PMA increased further transiently during the first weeks. The increases in P-selectin and in PMA indicate ongoing platelet activation during the early period of treatment.