Multiple cycles of recombinant human thrombopoietin therapy in a patient with chronic refractory idiopathic thrombocytopenic purpura.

We describe a 41-year-old woman with chronic idiopathic thrombocytopenic purpura who received recombinant human thrombopoietin (rhTPO) therapy. rhTPO was administrated subcutaneously at a dosage of 1.0 mug/kg daily for a maximum of 14 days until the platelet count was more than 50 x 10/l. The patient received three cycles (six, 13, and eight doses each) of rhTPO, each initiated when the platelet counts was less than 10 x 10/l. The platelet count increased to above 50 x 10/l on days 5, 11 and 8, and peaked at 456 x 10/l, 130 x 10/l and 82 x 10/l on days 9, 15 and 13 in the three respective cycles, each followed by a gradual decline. The durations of platelet counts at more than 50 x 10/l in the three cycles were 13, 7 and 10 days, respectively. rhTPO was well tolerated with no adverse event observed. Antibodies to rhTPO by enzyme-linked immunosorbent assay were not detected. Our observations suggested that rhTPO could transiently increase the peripheral platelet count in patients with chronic refractory idiopathic thrombocytopenic purpura. The reasons why the peak platelet counts decreased and the duration of response shortened after successive cycles of treatment were unclear.