PGY2 Hematology/Oncology Pharmacy Resident City of Hope National Medical Center Duarte, California, United States
Poster Abstract:
Background: Clinically relevant prolonged thrombocytopenia (platelet count < 50,000 cells/mm3) following allogeneic hematopoietic stem cell transplantation (HSCT) has a reported incidence of up to 37% and is independently associated with poorer post-HSCT outcomes including higher treatment-related mortality and poor overall survival. Causes of delayed platelet recovery are often multifactorial and may include medications, infections, and poor HSCT graft function. TPO mimetics, which stimulate platelet production by binding to TPO receptors in human hematopoietic stem cells and megakaryocytes, are a class of oral and injectable medications currently approved to treat immune-mediated thrombocytopenia (ITP). Eltrombopag is one of the available oral TPO mimetics. Although the use of eltrombopag for thrombocytopenia post-allogeneic HSCT is not currently an approved indication, there has been increasing evidence for its use in this context. However, data available involves heterogeneous study populations in small cohorts, and thus there is currently no strong consensus guidance on the usage of eltrombopag in this setting. By conducting an in-depth review at our institution, we hope to offer more insight into the efficacy and optimal usage of eltrombopag in the HSCT population.
Objectives: To investigate the efficacy and safety of usage of eltrombopag in patients with thrombocytopenia following allogeneic HSCT.
Methods: A retrospective chart review using electronic medical records was performed. Patients aged 18 years or older who had received eltrombopag following allogeneic HSCT between January 1, 2020 and December 31, 2022 were included for analysis. Patients who had previously received an autologous or allogeneic HSCT and those with a diagnosis of ITP were excluded. Patients were also excluded if they only received less than 7 days of eltrombopag at any dose. The primary outcome of the study is complete response rate - defined as the rate of platelet recovery to greater than or equal to 50,000 cells/mm3 for 7 consecutive days without platelet transfusion after TPO mimetic treatment initiation. Secondary outcomes include (1) median time to first achievement of platelet count greater than or equal to 50,000 cells/mm3 without transfusion, (2) duration of response after discontinuation of treatment, (3) change in number of platelet transfusions after TPO mimetic initiation, and (4) adverse events attributed to TPO mimetics.
