Recombinant Human Thrombopoietin Promotes The Recovery Of Megakaryocyte Lineage In Patients With Severe Aplastic Anemia Receiving Immunosuppressive Therapy

To assess the effectiveness of recombinant human thrombopoietin (rhTPO) in severe aplastic anemia (SAA) patients receiving immunosuppressive therapy (IST).

Eighty SAA patients receiving IST during a period from January 2007 to December 2011 were included in this retrospective analysis. Thirty-two subjects also received rhTPO treatment (15,000 U, three times a week, subcutaneously). The remaining 48 patients did not receive rhTPO treatment. The choice of using (or not using) rhTPO was based on physician discretion, and more importantly, patient will (partly based on financial capability to afford the medication). rhTPO was discontinued when platelet count returned to normal range. Hematologic response, bone marrow recovery, transfusion interval (platelet or red-cells), and the time to transfusion-free status were compared.

At 6^th months after the treatment, hematologic response along at least one lineage was achieved in 65.6% of the subjects receiving rhTPO vs. 41.7% in those who did not receive rhTPO (p=0.04). Response rate of megakaryocyte and erythroid lineage at 3rd months was also higher in subjects receiving rhTPO than in those who did not (43.8% vs. 10.4%, p=0.001; 50.0% vs. 20.8%, p=0.006). The mean number of megakaryocyte per bone marrow slide was higher in subjects receiving rhTPO than those who did not (9.7±3.1 vs. 2.6±4.2, p=0.002) after three months. The percentage of nucleated erythroid cells in bone marrow was also higher in subjects receiving rhTPO after three months (22.2±13.2% vs. 13.6±13.9% in those who did not receive rhTPO; p=0.007). The percentage of reticulocytes in peripheral blood was higher in subjects receiving rhTPO (1.9±1.4% vs. 0.7±0.4% in those who did not receive rhTPO; p=0.001) after three months. Myeloid percentage in bone marrow did not differ at any time points (3, 6, or 9 months). The need for platelet transfusion was lower in subjects receiving rhTPO (transfusion interval: 13.8±14.3 vs. 6.9±5.2 and 26.3±28.9 vs. 15.7±13.1 days in those who did not receive rhTPO during the first three and six months, respectively; P=0.004, P=0.03). The need for red cell transfusion was also lower in subjects receiving rhTPO (interval: 32.5±22.0 vs. 11.9±7.2 days and 50.4±27.9 vs. 23.9±20.1 days during the first three and six months, respectively; p=0.001 P=0.009). Time to independence from platelet transfusion was significantly shorter in subjects receiving rhTPO (99.9±49.9 vs. 156.3±14.5 days in those who did not receive rhTPO; p=0.01).

rhTPO improves hematologic response and promotes bone marrow recovery in SAA patients receiving IST.

No relevant conflicts of interest to declare.