The objectives of this study were to assess the safety and efficacy of darbepoetin alfa (Aranesp) administered every 2 weeks in anemic patients with solid tumors receiving chemotherapy. This was an open-label, randomized, active-controlled, multicenter dose-finding study evaluating a range of every-2-week darbepoetin alfa doses. The active control arm received epoetin alfa (Epogen, Procrit) at 40,000 U weekly with a dose increase to 60,000 U weekly for subjects with an inadequate response. The lowest clinically effective doses of darbepoetin alfa in this study were 3.0 and 5.0 microg/kg every 2 weeks, with no additional benefit observed at higher doses. The percentage of patients who achieved a hematopoietic response in the 3.0- and 5.0-microg/kg groups was 66% (95% confidence interval [CI] = 46%-86%) and 84% (95% CI = 67%-100%), respectively, compared with 63% (95% CI = 46%-81%) in the epoetin alfa group. Darbepoetin alfa administered at a dose of 3.0 microg/kg every 2 weeks is safe and effective for treating anemia in patients with solid tumors on chemotherapy, and is comparable to epoetin alfa. A dose increase to 5.0 microg/kg of darbepoetin alfa administered every 2 weeks may be appropriate in patients with an inadequate initial response.