Therefore, to characterize and understand the biological effects of romiplostim on hematopoiesis in humans, we studied the in vitro effects of romiplostim on human HSPCs and compared them with those of the recombinant human TPO (rhTPO) and another TPOR agonist—eltrombopag—which is an orally administered small molecule also approved for the clinical treatment of hematological disorders, including AA [11]. Here, TPO is linked to hematologic disorder.