A brush-polymer conjugate of exendin-4 reduces blood glucose for up to five days and eliminates poly(ethylene glycol) antigenicity.

Qi, Yizhi; Simakova, Antonina; Ganson, Nancy J; Li, Xinghai; Luginbuhl, Kelli M; Özer, Imran; Liu, Wenge; Hershfield, Michael S et al. · Nat Biomed Eng · 2016

basic_science · Level V

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Abstract

The delivery of therapeutic peptides and proteins is often challenged by a short half-life, and thus the need for frequent injections that limit efficacy, reduce patient compliance and increase treatment cost. Here, we demonstrate that a single subcutaneous injection of site-specific (C-terminal) conjugates of exendin-4 (exendin) - a therapeutic peptide that is clinically used to treat type 2 diabetes - and poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA) with precisely controlled molecular weights lowered blood glucose for up to 120 h in fed mice. Most notably, we show that an exendin-C-POEGMA conjugate with an average of 9 side-chain ethylene glycol (EG) repeats exhibits significantly lower reactivity towards patient-derived anti-poly(ethylene glycol) (PEG) antibodies than two FDA-approved PEGylated drugs, and that reducing the side-chain length to 3 EG repeats completely eliminates PEG antigenicity without compromising <i>in vivo</i> efficacy. Our findings establish the site-specific conjugation of POEGMA as a next-generation PEGylation technology for improving the pharmacological performance of traditional PEGylated drugs, whose safety and efficacy are hindered by pre-existing anti-PEG antibodies in patients.