Dosing patterns, drug costs, and hematologic outcome in anemic patients with chronic kidney disease switching from darbepoetin alfa to epoetin alfa

ABSTRACT Objective: To compare real-world dosing patterns, drug costs, and hematologic outcome in anemic chronic kidney disease (CKD) patients, not receiving dialysis, who switched from darbepoetin alfa (DARB) to epoetin alfa (EPO) in a community practice setting. Research design and methods: This retrospective observational chart review from a US nephrology clinic included 153 anemic CKD patients ≥ 18 years of age who did not receive dialysis during the study period, switched from DARB to EPO between 8/2003 and 8/2005, and received ≥ 2 doses of both agents. Paired t-test and McNemar's chi-square were performed comparing pre-switch and post-switch outcomes. Results: Mean interval between doses increased from 24.3 ± 11.1 days with DARB to 28.8 ± 19.8 days with EPO ( p = 0.001). Weighted mean pre-switch weekly dose for DARB was 25 µg, while weighted mean post-switch weekly dose for EPO was 7090 Units, resulting in a dose ratio (Units EPO:µg DARB) of 287:1. These doses resulted in mean weekly costs of $110 (DARB) and $86 (EPO). Mean hemoglobin (Hb) levels increased over time from 10.8 g/dL at 6 months pre-switch to 11.1 g/dL 6 months after EPO initiation ( p = 0.0132). Mean Hb levels were > 11 g/dL, but below 12 g/dL, while patients received EPO. Conclusions: Patients switching from DARB to EPO had a greater mean interval between doses, lower drug costs, and consistently maintained recommended Hb levels over time. Limitations: The reverse direction (EPO to DARB) was not investigated. Although treatment outcomes were not assessed in a randomized, controlled setting, the study's observational nature provided actual evidence in a real-world setting.