TPO and aplastic anemia: Romiplostim (ROM), a second-generation thrombopoietin receptor agonist (TPO-RA), has shown promising results in patients with refractory aplastic anemia (AA); however, its optimal dosage, efficacy, and safety in patients with refractory AA who experienced treatment failure with immunosuppressive therapy (IST) and other types of TPO-RAs remain unclear.