One to one comparison of cell-free synthesized erythropoietin conjugates modified with linear polyglycerol and polyethylene glycol

Abstract

With more than 20 Food and Drug Administration (FDA)-approved poly (ethylene glycol) (PEG) modified drugs on the market, PEG is the gold standard polymer in bioconjugation. The coupling improves stability, efficiency and can prolong blood circulation time of therapeutic proteins. Even though PEGylation is described as non-toxic and non-immunogenic, reports accumulate with data showing allergic reactions to PEG. Since PEG is not only applied in therapeutics, but can also be found in foods and cosmetics, anti-PEG-antibodies can occur even without a medical treatment. Hypersensitivity to PEG thereby can lead to a reduced drug efficiency, fast blood clearance and in rare cases anaphylactic reactions. Therefore, finding alternatives for PEG is crucial. In this study, we present linear polyglycerol (LPG) for bioconjugation as an alternative polymer to PEG. We report the conjugation of LPG and PEG by click-chemistry to the glycoprotein erythropoietin (EPO), synthesized in a eukaryotic cell-free protein synthesis system. Furthermore, the influence of the polymers on EPOs stability and activity on a growth hormone dependent cell-line was evaluated. The similar characteristics of both bioconjugates show that LPGylation can be a promising alternative to PEGylation.

In Vitro Biocompatibility and Endothelial Permeability of Branched Polyglycidols Generated by Ring-Opening Polymerization of Glycidol with B(C6F5)3 under Dry and Wet Conditions

“…Comparative studies of LPG-, HPG-and PEG-anakinra bioconjugates showed that LPG conjugates exhibited significantly better proteolytic stability than their PEG analogues, and all conjugates significantly prolonged the elimination half-life of anakinra, with LPG and PEG conjugates prolonging it 4-fold compared to the unmodified protein. 15 Other bioconjugation studies were performed to compare the performance of LPG-and PEG-modified proteins (e.g., interleukin-4 WT, 16 interferon α2a, 17 and erythropoietin 18 ) in terms of their bioactivity. The PEGylated and PGylated forms of interleukin-4 WT and erythropoietin showed similar biological activities, whereas those of interferon α2a showed different pharmacokinetics.…”

“… 15 Other bioconjugation studies were performed to compare the performance of LPG- and PEG-modified proteins ( e.g. , interleukin-4 WT, 16 interferon α2a, 17 and erythropoietin 18 ) in terms of their bioactivity. The PEGylated and PGylated forms of interleukin-4 WT and erythropoietin showed similar biological activities, whereas those of interferon α2a showed different pharmacokinetics.…”