AGEM400(HES), a Novel Erythropoietin Mimetic Peptide Conjugated to Hydroxyethyl Starch with Excellent in vitro Efficacy

摘要

We developed and tested a compound called AGEM400(HES) that consists of a novel erythropoietin mimeticpeptide (EMP) which is produced as a continuous N- to C-linked dimer and is conjugated to biodegradable hydroxyethylstarch (HES). In various in vitro assays, AGEM400(HES) demonstrated excellent efficacy, better than the peptide alone,and comparable to the efficacy of erythropoietin (EPO) and Aranesp (Darbepoietin alpha). The assays included survivalassays on EPO-responsive cell lines (EC50 below 1 ng/ml peptide) and clonogenic assays on human bone marrowcells (EC50 1 to 10 ng/ml). AGEM400(HES) caused phosphorylation of STAT5 and ERK signalling proteins in UT7/EPOcells in a similar fashion as EPO. AGEM400(HES) replaced EPO from its receptor and the in vitro activity of AGEM400(HES) was inhibited by soluble EPO receptor. Antibodies generated in mice and rabbits against EPO did not recognizeAGEM400(HES) peptide, and vice versa. A sensitive ELISA was able to detect AGEM400(HES) at low nanogram perml concentrations which allows for bioanalytics of AGEM400(HES) serum levels in future in vivo studies. As a result,AGEM400(HES) is a promising drug candidate for anemias related to renal insufficiency and/or in oncological settings.