Abstract Background: Equivalence of intravenous (i.v.) and subcutaneous (s.c.) dosage requirements is a notable characteristic of darbepoetin-α (DPO), as opposed to other epoetins (EPOs). Currently in Europe, the EPOs/DPO conversion factor (200 IU EPOs = 1 μg DPO) does not take into account the route of drugs administration. To better define this ratio we have conducted a prospective, long-term trial in a group of hemodialysis patients. Subjects and methods: At the start, we evaluated 40 iron-replete hemodialysis patients, but the final study was performed in the remaining 25 patients. During the first 6 months, patients were on i.v. epoetin-α (EPOα) maintenance therapy (phase 1: T-6 to T0). After conversion to i.v. DPO (initial 200:1 ratio) the observation was prolonged for a period of 12 months (phase 2: T0 to T12). DPO was administered at extended dose intervals and the EPOα/DPO rate was adjusted every month to maintain hemoglobin (Hgb) stability. Iron status and factors inhibiting erythropoiesis were continually checked to exclude unstable patients. Results: Phase 1: EPOα weekly mean dose showed no significant variation. Phase 2: EPOα/DPO conversion factor progressively rose from 200 to 256.7 ± 86.9 IU/μg at T7 (p0.005) and 336.8 ± 104.3 IU/μg at T12 (p0.0005). DPO weekly mean dosage decreased from 40.0 ± 12.0 μg/week at T0 to 31.6 ± 3.7 μg/week at T7 (p0.005) and 24.6 ± 7.0 μg/week at T12 (p0.0005). Mean weekly/patient acquisition cost of EPOα was €70.6 ± 21.3 (T-6 to T0); after switching, the cost of DPO was €72.4 ± 22.7 (T0) and fell to €53.1 ± 11.2 during T6 to T12. Conclusions: The progressive increase of EPOα/DPO ratio demonstrated that i.v. DPO requires lower doses compared with i.v. EPOα. When drugs are administered i.v., the starting EPOα/DPO conversion factor should be increased over the 200:1 ratio, similar to recommendations outlined in the United States and Japan. DPO dose reduction translated to notable cost-savings.
Icardi et al. (Mon,) studied this question.