Eltrombopag for Treatment of Thrombocytopenia after Allogeneic Hematopoietic Cell Transplantation

• Eltrombopag was effective in 60% of cases of prolonged isolated thrombocytopenia after hematopoietic cell transplantation
• Eltrombopag was effective in 71% of cases of secondary failure of platelet recovery after hematopoietic cell transplantation
• The number of bone marrow megakaryocytes predicted response to eltrombopag
• No patient discontinued eltrombopag because of adverse events or intolerability

Persistent thrombocytopenia is a common complication after allogeneic hematopoietic cell transplantation (HCT). Eltrombopag is an oral thrombopoietin receptor agonist whose efficacy against persistent thrombocytopenia after allogeneic HCT has not been well characterized. This retrospective study evaluated the safety and efficacy of eltrombopag in 12 consecutive patients with persistent thrombocytopenia after allogeneic HCT. Eltrombopag was started at 12.5 mg once daily and the dose was increased by 12.5 mg daily every week until platelet counts exceeded 50,000/μL. Five patients had prolonged isolated thrombocytopenia (PIT) and 7 patients had secondary failure of platelet recovery (SFPR). The cumulative incidence rate of successful platelet recovery to ≥50,000/μL without transfusion support was 60% in PIT patients and 71% in SFPR patients. No patients discontinued the drug because of adverse events or intolerability. Notably, the rate of platelet recovery was higher (100% versus 58%; P = .0017) and recovery was faster (median, 33 days versus 137 days; P = .0078) in patients with normal numbers of bone marrow megakaryocytes before starting eltrombopag than in those with decreased numbers of megakaryocytes. Eltrombopag is a promising treatment for both PIT and SFPR after allogeneic HCT. The number of megakaryocytes in bone marrow before eltrombopag treatment may predict the response to eltrombopag.