Browsing by Subject "erythropoietin"

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    Biosimilars—Emerging Role in Nephrology
    (American Society of Nephrology, 2019-09-01) Wish, Jay B.; Medicine, School of Medicine
    The Food and Drug Administration (FDA) defines a “biosimilar” agent as a biologic that is highly similar to the reference or originator biologic product notwithstanding minor differences in clinically inactive components with no clinically meaningful differences in terms of the safety, purity, and potency. The advantage of biosimilars is that they are usually about 15%–30% less expensive than the reference product, which results in system-wide cost savings and increased patient access. Because biologic drugs are produced by living organisms, they are by nature heterogeneous and identical copies cannot be made, unlike generic versions of small-molecule drugs. Proposed biosimilars must undergo a rigorous evaluation process to demonstrate a high degree of structural and functional similarity with the reference biologic. Once that is confirmed, a stepwise process of comparison with the reference agent with regard to animal trials, pharmacokinetics/pharmacodynamics, immunogenicity, and human efficacy/safety is conducted. The experience with biosimilars in other highly regulated markets where patent protection for originator biologics is not as robust as in the United States has been favorable in terms of safety, efficacy, and cost savings. An FDA approval pathway was created in 2009 to expedite the approval of biosimilars; as of early 2018 nine agents had been approved through that pathway, none in nephrology. The first United States biosimilar epoetin was approved on May 15, 2018, but does not have an interchangeability designation, meaning that prescribers must specifically write for the biosimilar product for patients to receive it. Given the unfamiliarity of biosimilars within the nephrology community it is recommended that educational programs be developed to address this unmet need and for research to be conducted addressing the perceptual, clinical, and economic effect of biosimilars on our patients.
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    Mechanisms and mediators of hypertension induced by erythropoietin and related molecules
    (Oxford, 2018-10) Agarwal, Rajiv; Medicine, School of Medicine
    Hypertension is a common but frequently overlooked adverse effect of erythropoietin (EPO) therapy. Underreporting of hypertension with EPO is likely due to either more aggressively managing hypertension through the prescription of antihypertensive drugs or closer attention to dry weight. The purpose and focus of this review is to critically evaluate the mechanisms of EPO-induced hypertension. Preclinical data are considered first, followed by clinical data where available. Mediated by a variety of molecules, there is an imbalance in the vascular tone favoring net vasoconstriction that mediates EPO-induced hypertension. Animal studies show the primary importance of chronic kidney disease in the genesis of EPO-induced hypertension. Preclinical studies show deranged regulation of the nitric oxide, endothelins and porstanoids and the sympathoadrenal and renin–angiotensin pathways as causes of EPO-induced hypertension. Human studies suggest that EPO administration is also associated with increased responsiveness to catecholamines and angiotensin II on vascular tissue; in addition, hypoxia-induced vasodilation may be impaired in those with EPO-induced hypertension. There is little evidence for EPO as a direct vasoconstrictor or its effect on blood viscosity as a mechanism of EPO-induced hypertension. EPO-induced hypertension, at least in part, appears to be independent of an increase in hemoglobin, because experiments show that hemoglobin may be increased by EPO without an increase in blood pressure (BP) by simply treating the animals with EPO-binding protein and that treatment with EPO in the setting of iron deficiency may not increase hemoglobin but may still increase BP. However, experimental data are not consistent across studies and better mechanistic designs are needed, especially in patients with chronic kidney disease, to dissect the precise mechanism of EPO-induced hypertension. Animal studies suggest that hypoxia-inducible factor stablizers may induce hypertension by provoking calcification and augmenting chronic intermittent hypoxia as occurs in sleep apnea. Others show that there may be an antihypertensive effect via kidney repair. Whether these drugs will alter the risk of hypertension compared with EPO remains to be seen.