A recombinant polypeptide extends the in vivo half-life of peptides and proteins in a tunable manner

Abstract

Increasing the in vivo residence times of protein therapeutics could decrease their dosing frequencies. We show that genetic fusion of an unstructured recombinant polypeptide of 864 amino acids, called XTEN, to a peptide or protein provides an apparently generic approach to extend plasma half-life. Allometric scaling suggests that a fusion of XTEN to the exenatide peptide should increase exenatide half-life in humans from 2.4 h to a projected time of 139 h. We confirmed the biological activity of the exenatide-XTEN fusion in mice. As extended stability might exacerbate undesirable side effects in some cases, we show that truncating the XTEN sequence can regulate plasma half-life. XTEN lacks hydrophobic amino acid residues that often contribute to immunogenicity and complicate manufacture. Based on data on XTEN fusions to exenatide, glucagon, GFP and human growth hormone, we expect that XTEN will enable dosing of otherwise rapidly cleared protein drugs at up to monthly intervals in humans.

In situ growth of a PEG-like polymer from the C terminus of an intein fusion protein improves pharmacokinetics and tumor accumulation

“…It is interesting to compare these results with a recent report on an unstructured polypeptide -XTEN-that was developed by high throughput screening for high-level overexpression and a long plasma half-life; a GFP-XTEN fusion exhibited a terminal half-life in rats of 29 h upon i.v. injection (39). Although cross-species comparison of pharmacokinetics is somewhat problematic, evaluation of the pharmacokinetic data for GFP-C-poly(OEGMA) in mice with that of XTEN fused to GLP-1 and GFP across different species suggests that a once- The data in Fig.…”

Polymers for Protein Conjugation

“…[106]. The approach was tested using different peptides and proteins, such as exenatide, glucagon and hGH [106][107][108]. A novel recombinant human growth hormone (rhGH) fusion protein was designed by genetically fusing different XTEN sequences to the protein's N-and C-terminus, obtaining a fused protein of about 119 kDa, with a five-fold M W increase with respect to the original hGH.…”

“…XTEN technology is based on the genetic fusion of a gene encoding for an active protein with a gene encoding for long unstructured hydrophilic sequences of amino acids [106,107]. A XTEN peptide is composed of six amino acids (A, E, G, S and T) at different percentages.…”

“…The sequence was selected from a large library by evaluating parameters, such as maximal expression, genetic stability, solubility, aggregation resistance, etc. [106]. The approach was tested using different peptides and proteins, such as exenatide, glucagon and hGH [106][107][108].…”

Pyroglutamate and O-Linked Glycan Determine Functional Production of Anti-IL17A and Anti-IL22 Peptide-Antibody Bispecific Genetic Fusions

“…Albumin-peptide fusion proteins (19) take advantage of the long half-life of human albumin. Most recently, a randomly engineered de novo polypeptide XTEN (20) is reported to extend half-life of the exenatide. The CovX body, consisting of synthetic peptides chemically conjugated to a humanized catalytic aldolase antibody (21), has also been found, effectively extending the half-life of bispecific peptide heterodimers (22).…”