Thrombopoietin (TPO) is the most important cytokine to promote platelet production in human body. TPO acts to promote platelet production by binding to the TPO receptor (TPO-R) on the cell surface. TPO receptor agonists (TPO-RA) mimic the structure of TPO to bind and activate TPO-R, and effectively stimulate platelet production. Currently, TPO-RA entering clinical applications include recombinant human TPO (rhTPO), peptide TPO-RA, and non-peptide TPO-RA. TPO-RA are mainly applied for the treatment of relapsed/refractory immune thrombocytopenia (ITP). In addition, TPO-RA can be used to treat thrombocytopenia caused by other causes, including refractory severe aplastic anemia (r-SAA), hematopoietic stem cell transplantation (HSCT), myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML), lymphoproliferative disorder (LPD), chemotherapy of solid tumor, and to treat thrombocytopenia induced by liver disease in perioperative period. This article summaries the biosynthesis and mechanisms of TPO, classifications of TPO-RA, TPO-RA mechanisms of action, clinical application, efficacy and safety.
