Retrospective observational study of patients with chemotherapy-related anemia receiving erythropoietic agents

OBJECTIVE: Epoetin alfa (EPO) and darbepoetin alfa (DARB) are approved for the treatment of chemotherapy-related anemia (CRA) in patients with nonmyeloid malignancies. This study examined dosing and hematologic outcomes with these agents in community oncology clinics.

METHODS: Medical charts were abstracted retrospectively for 1005 patients (527 EPO, 478 DARB) with CRA (hemoglobin [Hb] < or = 11 g/dL) who received EPO or DARB at 10 U.S. oncology clinics between January 2002 and March 2003.

MAIN OUTCOME MEASURES: Outcome measures included dose and frequency of erythropoietic therapy, change in Hb at 4, 8, and 12 weeks after initiation of therapy, and transfusion of packed red blood cells.

RESULTS: Baseline characteristics were generally similar between groups. Most EPO-treated patients received EPO once weekly, but 25% received EPO every 2-3 weeks, with 40,000 U the predominant dose. DARB was usually given every 1-2 weeks in doses ranging from 200-400 mcg/injection. Mean treatment duration was relatively short (< 8 weeks) in both groups, with a similar number of Hb determinations and similar incidence of red blood transfusion between groups. Hb increased from baseline in the EPO and DARB groups at 4 weeks (0.99 vs. 0.69 g/dL, p = 0.003), 8 weeks (1.39 vs. 1.06 g/dL, p = 0.011), and 12 weeks (1.43 vs. 1.11 g/dL, p = 0.055). Early Hb response (> or = 1 g/dL increase by 4 weeks) was more common with EPO than DARB (48% vs. 38%, p = 0.008).

CONCLUSIONS: EPO was superior to DARB for early hematologic outcomes in patients with CRA in community oncology clinics. Retrospective data collection and relative inexperience with DARB at the time of the study may limit the generalization of these results. Randomized, controlled trials comparing EPO and DARB are warranted.