Once-monthly darbepoetin alfa for maintaining hemoglobin levels in older patients with chronic kidney disease.

OBJECTIVES: To evaluate the efficacy of once-monthly darbepoetin alfa in maintaining hemoglobin (Hb) levels between 10 and 12 g/dL in older subjects receiving darbepoetin alfa every 2 weeks. DESIGN: A secondary analysis of a 29-week multicenter, open-label, single-arm study with an initial 2-week screening/baseline period, followed by a 20-week once-monthly darbepoetin alfa dose titration period and an 8-week evaluation period. SETTING: Twenty treatment centers in the United States. PARTICIPANTS: Subjects with CKD who were not receiving dialysis and whose hemoglobin levels were > or =10 g/dL with darbepoetin alfa every 2 weeks. INTERVENTION: Darbepoetin alfa administered once monthly and titrated to maintain Hb level between 10 and 12 g/dL, inclusive. MEASUREMENTS: The proportion of subjects maintaining a mean Hb concentration of 10 to 12 g/dL, inclusive, while receiving once-monthly darbepoetin alfa during the evaluation period (weeks 21 to 29); the mean change in Hb levels and darbepoetin alfa doses between baseline and the evaluation period; and the treatment relationship, frequency, severity, and outcomes of all adverse events. Analyses were stratified by age (<65, > or =65, and > or =75 years). RESULTS: Seventy-nine percent of subjects aged > or =65 years and 80% of subjects aged > or =75 years maintained their Hb levels within the specified target range, compared with 80% of subjects aged <65 years who maintained their Hb levels within the specified target range. Hemoglobin levels and darbepoetin alfa doses did not change significantly from baseline to the evaluation period. Darbepoetin alfa administered once monthly was well tolerated in all age groups. CONCLUSION: Darbepoetin alfa administered once monthly effectively maintained target Hb levels in older subjects with CKD (not receiving dialysis) who were maintained previously with an every 2 weeks darbepoetin alfa regimen.

Pharmacokinetics and pharmacodynamics of darbepoetin alfa and epoetin in patients undergoing dialysis.

OBJECTIVE: The aim of this multicenter, randomized, open-label study was to compare the pharmacokinetic and pharmacodynamic profiles of darbepoetin alfa, a new erythropoiesis-stimulating protein, and recombinant human erythropoietin (epoetin) after repeated intravenous dosing in patients with chronic kidney disease receiving hemodialysis. METHODS: Forty-seven patients were randomized to receive darbepoetin alfa administered once weekly (n = 17) or 3 times weekly (n = 15) or epoetin administered 3 times weekly (n = 15) for up to 52 weeks. Pharmacokinetic profiles were measured during weeks 1 and 12 and at hemoglobin steady state (defined as a hemoglobin concentration within the target range for 4 consecutive weeks after week 12 with no change in study drug dose) or between weeks 36 and 40, whichever occurred first. RESULTS: At each of the 3 time points evaluated, the terminal half-life of darbepoetin alfa was 2 to 3 times longer and the clearance approximately 4 times slower than those of epoetin. At week 12, the terminal half-life was 23.4 hours with darbepoetin alfa once weekly, 18.3 hours with darbepoetin alfa 3 times weekly, and 8.0 hours with epoetin 3 times weekly. The pharmacokinetics of darbepoetin alfa was not dependent on dose or time. Mean hemoglobin values at steady state were all approximately 11 g/dL, within the target range of 9.0 to 13.0 g/dL. Safety analyses revealed no differences between darbepoetin alfa and epoetin. CONCLUSIONS: The pharmacokinetic and pharmacodynamic profiles and safety data for darbepoetin alfa demonstrate that it can be administered less frequently than epoetin in patients with chronic kidney disease receiving hemodialysis, thus simplifying anemia management.