The safety and efficacy of darbepoetin alfa (Aranesp) at 3.0 microg/kg administered every 2 weeks and recombinant human erythropoietin (rHuEPO) given as 40,000 U weekly or 150 U/kg three times weekly were evaluated by pooling data from three darbepoetin alfa clinical studies. All studies enrolled anemic (hemoglobin < or = 11.0 g/dL) patients receiving multicycle chemotherapy. Open-label study drug was administered by subcutaneous injection. Hemoglobin concentrations, red blood cell transfusion requirements, and standard safety parameters were evaluated. Of 260 patients who received darbepoetin alfa at 3.0 microg/kg every 2 weeks and 115 patients who received rHuEPO three times weekly or once weekly, hematopoietic response (change in hemoglobin from baseline of > or = 2 g/dL or hemoglobin concentration of > or = 12 g/dL) was achieved in 71% (95% confidence interval [CI] = 65%-78%) of patients who received darbepoetin alfa every 2 weeks, comparable to the response in patients who received rHuEPO (71%; 95% CI = 61%-81%). The mean increase in hemoglobin concentration over 13 weeks was also similar: 1.48 g/dL (95% CI = 1.28-1.68 g/dL) for darbepoetin alfa and 1.31 g/dL (95% CI = 0.97-1.64 g/dL) for rHuEPO. The proportion of patients in the darbepoetin alfa group requiring transfusions was lower (7%; 95% CI = 4%-11%) than that in the rHuEPO group (14%; 95% CI = 8%-22%). Darbepoetin alfa every 2 weeks was well tolerated with a safety profile comparable to that of rHuEPO. In conclusion, darbepoetin alfa at a dose of 3.0 microg/kg given every 2 weeks safely increases hemoglobin concentration to the same extent as rHuEPO.