Definition

An orally available small molecule agonist of the platelet thrombopoietin (TPO) receptor (TPOR; MPL), with potential megakaryopoiesis stimulating activity. Upon administration, totrombopag mimics TPO and binds to TPOR. This stimulates TPOR and leads to the proliferation and differentiation of megakaryocytes in the bone marrow. This increases the production of blood platelets and decreases bleeding in thrombocytopenic patients. TPOR is a cytokine receptor and member of the hematopoietin receptor superfamily.