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Background: Adequately powered studies directly comparing hard clinical outcomes of darbepoetin alfa (DPO) versus epoetin alfa (EPO) in patients undergoing dialysis are lacking., Study Design: Observational, registry-based, retrospective cohort study; we mimicked a cluster-randomized trial by comparing mortality and cardiovascular events in US patients initiating hemodialysis therapy in facilities (almost) exclusively using DPO versus EPO., Setting & Participants: Nonchain US hemodialysis facilities; each facility switching from EPO to DPO (2003-2010) was matched for location, profit status, and facility type with one EPO facility. Patients subsequently initiating hemodialysis therapy in these facilities were assigned their facility-level exposure., Intervention: DPO versus EPO., Outcomes: All-cause mortality, cardiovascular mortality; composite of cardiovascular death, nonfatal myocardial infarction (MI), and nonfatal stroke., Measurements: Unadjusted and adjusted HRs from Cox proportional hazards regression models., Results: Of 508 dialysis facilities that switched to DPO, 492 were matched with a similar EPO facility; 19,932 (DPO: 9,465 [47.5%]; EPO: 10,467 [52.5%]) incident hemodialysis patients were followed up for 21,918 person-years during which 5,550 deaths occurred. Almost all baseline characteristics were tightly balanced. The demographics-adjusted mortality HR for DPO (vs EPO) was 1.06 (95% CI, 1.00-1.13) and was materially unchanged after adjustment for all other baseline characteristics (HR, 1.05; 95% CI, 0.99-1.12). Cardiovascular mortality did not differ between groups (HR, 1.05; 95% CI, 0.94-1.16). Nonfatal outcomes were evaluated among 9,455 patients with fee-for-service Medicare: 4,542 (48.0%) in DPO and 4,913 (52.0%) in EPO facilities. During 10,457 and 10,363 person-years, 248 and 372 events were recorded, respectively, for strokes and MIs. We found no differences in adjusted stroke or MI rates or their composite with cardiovascular death (HR, 1.10; 95% CI, 0.96-1.25)., Limitations: Nonrandom treatment assignment, potential residual confounding., Conclusions: In incident hemodialysis patients, mortality and cardiovascular event rates did not differ between patients treated at facilities predominantly using DPO versus EPO., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: HX575, licensed under the brand names Binocrit®, Epoetin Alfa Hexal®, and Abseamed®, was approved in 2007 as the first biosimilar recombinant human erythropoietin alfa (epoetin alfa) in the EU using Erypo®/Eprex® as reference product., Objectives: The aim of this study was to investigate the bioequivalence and potency of registered epoetin alfa products that have not been compared before in a randomized controlled clinical study., Methods: The study was conducted in two parts: part A compared the European-marketed HX575 and the US-marketed Epogen®; part B compared the European-marketed Erypo®/Eprex® and HX575 manufactured at two different drug substance production sites (HX575-TT denoting the already-approved technology-transfer product from an additional manufacturing site). In analyses across both study parts, Epogen® was exploratorily compared with Erypo®/Eprex®. A dense-sampling 48-hour pharmacokinetic profile was recorded at steady state after 11 doses of 100 IU epoetin alfa per kg of bodyweight. The hemoglobin response over 4 weeks of study medication administration was analyzed as the primary efficacy surrogate parameter using an ANCOVA model with the baseline value as co-variate. The per-protocol population comprised a total of 268 subjects, 76 in part A (equally randomized to HX575 or Epogen®) and 192 in part B (equally randomized to HX575, HX575-TT, or Erypo®/Eprex®). Pairs of study arms were compared in terms of the ratio of the mean epoetin alfa area under the curve (AUC) and the ratio of the mean hemoglobin area under the effect curve (AUEC)., Results: Bioequivalence was shown in all pair-wise comparisons with the 90% confidence intervals of the AUC ratios falling within the standard bioequivalence limits of 80-125%. Moreover, an equivalent pharmacodynamic response was achieved with all compared epoetin alfa products, as confirmed by the hemoglobin AUEC ratio's 90% CI falling within the predefined acceptance margins of 96.8-103.2%. Thus, bioequivalence and equivalent potency was demonstrated for HX575 and Epogen® in part A of the study, as well as for HX575, HX575-TT and Erypo®/Eprex® in part B of the study. Pair-wise comparison across study parts indicated similar pharmacokinetic and pharmacodynamic profiles of Epogen® and Erypo®/Eprex®. All compared epoetin alfa products were well tolerated and had a similar safety profile. No subject developed anti-erythropoietin antibodies upon administration of study medication., Conclusion: The results show, for the first time in a prospective randomized clinical study, equivalent bioavailability at steady state and similar potency of the US-marketed Epogen® and the European-marketed Binocrit®. Differences in the formulation between the epoetin alfa products had no apparent clinical impact. The high degree of similarity between Epogen® and Erypo®/Eprex® provides justification for linking and comparing results from clinical studies that were conducted using either US- or European-marketed epoetin alfa products.

Background and Objectives: Emerging evidence suggests that epoetin alfa can be administered at extended intervals of up to 4 wk. This open-label, randomized study was performed to characterize the pharmacokinetic and pharmacodynamic profiles of four dosing regimens of epoetin alfa administered subcutaneously in anemic patients who had chronic kidney disease and were not on dialysis., Design, Setting, Participants, & Measurements: Thirty-eight patients, enrolled from nine centers in the United States, were > or =18 yr of age and had hemoglobin <11.0 g/dl and GFR 12 to 60 ml/min per 1.73 m(2). Patients received one of four epoetin alfa dosing regimens: 50 IU/kg three times per week, 10,000 IU once weekly, or 20,000 IU every 2 wk for 36 d or 40,000 IU every 4 wk for 64 d. Each regimen provided a similar dosage of epoetin alfa over 4 wk. Dosage adjustments were not permitted., Results: Drug exposure to epoetin alfa over 4 wk, based on area under the curve, was somewhat higher with the extended interval regimens compared with the three-times-weekly regimen. Mean change in hemoglobin during the study period was similar for all regimens. No patients were transfused. Three patients experienced five serious adverse events, none of which was considered treatment related., Conclusions: Extended dosing interval regimens of epoetin alfa yielded modest pharmacokinetic differences but a similar pharmacodynamic response, suggesting that less frequent, higher dosages of epoetin alfa may be as effective as the current three-times-weekly regimen in anemic patients who have chronic kidney disease and are not on dialysis.

Anemia treatment in nondialysis chronic kidney disease (ND-CKD) and dialysis CKD patients (D-CKD) has been recently scrutinized in the literature and by the lay press. New evidence suggests that patients receiving epoetin and achieving higher hemoglobin have a higher risk of death and cardiovascular complications. Data from the Centers for Medicare & Medicaid Services demonstrate upward spiraling costs of injectables, especially epoetin, in the care of CKD patients. There is considerable literature favoring the use of subcutaneous administration of epoetin compared to intravenous route in hemodialysis patients. Evidence clearly shows that the subcutaneous route achieves the target hemoglobin level at a lower administered dose. Thus, the same clinical effect can be achieved at a lower cost. Despite the economic and evidentiary justifications for subcutaneous administration of epoetin, adoption of this strategy has been limited, especially in the United States. Reasons include: inflexibility by dialysis providers because of reduced profitability, claims that patients oppose the subcutaneous route because of pain at the site of injection, concerns regarding pure red cell aplasia associated with subcutaneous administration, and greater hemoglobin cycling with the subcutaneous route. In this article, the advantages and disadvantages of the subcutaneous route are reviewed.

Patents of innovator biopharmaceutical products, such as epoetin, are expiring, and biosimilar versions of these products may soon enter European and American markets. Copies of these products, termed biosimilars or follow-on biologics, are not truly equivalent and cannot gain market approval through the procedure typically applied to generic drugs. We evaluated literature reports of both analytic and clinical studies conducted with biosimilar epoetin products currently marketed outside the United States and Europe in light of recently implemented European Medicines Evaluation Agency guidelines. The analytic studies reported that products differed widely in composition, did not always meet self-declared specifications, and exhibited batch-to-batch variation. Although several clinical studies demonstrated correction of anemia with biosimilar epoetins by using an open-label or placebo-controlled study design, only 4 of 22 studies were competitor controlled. Most of the studies were small (median 41 patients, range 18-1079 patients) and of short duration (median 12 wks, range 6 wks-1 yr). Clinical experience with epoetin shows that the dosage required to achieve similar hemoglobin levels varies among patients, making it impossible to demonstrate bioequivalence without a comparator. The analytic reports did not demonstrate comparability of biosimilar epoetin products with innovator epoetin alfa, and the clinical studies were not rigorous enough to show equivalent safety and efficacy of a biopharmaceutical product. The variation between products illustrates the challenge in replicating and consistently producing biopharmaceutical proteins. Immunogenic reactions with epoetin indicate that large, long-term studies are needed to adequately monitor safety.