TPO and idiopathic aplastic anemia: While the therapeutic rationale for hetrombopag remains partially unclear, though TPO-RAs have been proposed to stimulate hematopoiesis via TPO receptors on early progenitor cells31—analogous to endogenous TPO’s role in regulating and maintaining hematopoietic stem cells32—this theory conflicts with the naturally elevated TPO levels observed in aplastic anemia patients33.