Reticulocytes can represent an early indicator of erythropoietic response to Darbepoetin alfa in the anemia by chemotherapy

Background: Darbepoetin is a new drug active in anemia from chemotherapy and 2-to 3- times longer serum half life then recombinant-human Epo (rHuEPO). Reticulocytes can constitute an useful parameter to check the medullar reserve and give an indication of the erythropoietic answer. Methods: 42 patients in chemotherapy were randomised in 3 groups: the first two reported severe asthenia and have been deal respective with (I) darbepoetin 2.25μg/kg once weekly or (II) rHuEPO 150 U/Kg three times weekly; the third group (III), used like control, did not report relevant asthenic symptoms. The study evaluated time zero, after 4 and 8 weeks hemoglobin, reticulocyte count,serum ferritin, transferrin and iron. Results: The group treated with darbepoetin reported an increase of Hb after 4 weeks of approximately 2 g/dl if the starting value were >10 g/dl (8pts), instead patients with values of Hb <10g/dl evidenced a lower improvement of Hb (approximately 1 g/dl after 8 weeks). In the same group 13/15 pts reported an important improvement of reticulocytes. The mean value increased from 12,3 to 30,4μl (range 19–66); five patients exceeded the 14,5 g/dl of Hb. Group treated with rHuEPO showed a lower increase of reticulocytes after 8 weeks, the mean value increase from 17,2 to 22,6μl (range 13 - 34). In the control group reticulocytes moved by 15,0 to 12,0μl (range 2–16) and hemoglobin value decreased during chemotherapy from 10,5 to 9,7 g/dl. Conclusions: We reported a significantly increase of reticulocytes after four and eight weeks in the group treated with darbepoetin, higher than the group with rHuEPO and much more than the control group. Therefore our study show that darbepoetin is the sooner effective drug in the improvement of anemia. We besides suggest that reticulocyte count is a very important parameter in the prediction of response to the erythropoietic agents.