Table 1.

Comparison of the thrombopoietin receptor agonists.

	Romiplostim	Eltrombopag	Avatrombopag	Lusutrombopag	Hetrombopag
Molecular structure	Peptide	Small molecule	Small molecule	Small molecule	Small molecule
TPO receptor site of action	Extracellular domain	Transmembrane domain	Transmembrane domain	Transmembrane domain	Transmembrane domain
Route of administration	Subcutaneous	Oral	Oral	Oral	Oral
Dosing frequency a	Weekly	Daily	Daily or less frequently than daily	Daily	Daily
Relevant food interactions	N/A	Yes	No	No	Yes
Known hepatotoxicity	No	Yes	No	No	Yes
Possible plasma, skin, and sclerae discoloration	No	Yes	No	No	No
Iron chelator	No	Yes	No	No	Yes
May require lower starting dose in persons of East Asian ethnicity	No	Yes	No	No	Yes
Requires dose-reduction in hepatic dysfunction	No	Yes	No	No	Yes
Demonstrated increased thrombosis risk in chronic liver disease	No	Yes	No	No	No
Data exists for use in pregnancy b	Yes	Yes	No	No	No
Safety data available for extended durationc use	Yes	Yes	No	No	No
Current FDA-approved indications	Immune thrombocytopenia (adults and children) Acute radiation syndrome	Immune thrombocytopenia (adults and children) Hepatitis C-associated thrombocytopenia Severe aplastic anemia	Periprocedural thrombocytopenia in CLD patients Immune thrombocytopenia (adults)	Periprocedural thrombocytopenia in CLD patients	None (approved in China for management of immune thrombocytopenia and severe aplastic anemia)

^aPer drug label. Like avatrombopag, eltrombopag can be dosed less frequently than once daily [73] though this is not in the drug label.

^bNo TPO-RAs are approved for use in pregnancy for any indication. Available data in pregnancy is in patients with ITP.

^cDefined here as 5 or more years of continuous use.

TPO, thrombopoietin. CLD, chronic liver disease. N/A, not applicable.