Chemotherapy Induced Thrombocytopenia in Ewing Sarcoma, Implications and
Potential for Romiplostim Supportive Care
Abstract
Background: Maintaining dose-dense, interval-compressed chemotherapy
improves survival in Ewing sarcoma patients but is limited by
myelosuppression. Romiplostim is a thrombopoietin receptor agonist that
may be useful in the treatment of chemotherapy-induced thrombocytopenia
(CIT). Methods: Patients aged between 3 and 33 years with Ewing sarcoma
from 2010-2020 were reviewed. CIT was defined as a failure to achieve
75,000 platelets per microliter by day 21 after the start of any
chemotherapy cycle. Fisher exact test was used for univariate analysis
and Pearson’s correlation coefficient was used for the association
between continuous variables. Results: 27 out of 42 patients (64%)
developed isolated CIT, delaying one to four chemotherapy cycles per
patient. CIT occurred during consolidation therapy in 24/27(88.9%) and
with ifosfamide/etoposide cycles in 24/27 (88.9%). Univariate analysis
failed to identify risk factors for CIT. The use of radiation approached
significant (p value=0.056). Ten patients received romiplostim. The
median starting dose was 3 (range 1-5) mcg/kg. Doses were escalated
weekly by 1-2 mcg/kg to 4-10 mcg/kg and continued throughout
chemotherapy. A higher romiplostim dose was associated with a higher
change in average platelet counts from baseline r= 0.73 (p=0.04). No
romiplostim-related adverse events were identified aside from mild
headache. Conclusions: CIT is the primary reason for the inability to
maintain treatment intensity in Ewing sarcoma. The concurrent use of
romiplostim with chemotherapy is safe and feasible, and efficacy was
associated with higher romiplostim doses.