Enhanced disulphide bond stability contributes to the once-weekly profile of insulin icodec

Abstract Insulin icodec is a once-weekly insulin analogue that has a long half-life of approximately 7 days, making it suitable for once weekly dosing. The Insulin icodec molecule was developed based on the hypothesis that lowering insulin receptor affinity and introducing a strong albumin-binding moiety would result in a long insulin half-life, provided that non-receptor-mediated clearance is diminished. Here, we report an insulin clearance mechanism, resulting in the splitting of insulin molecules into its A-chain and B-chain by a thiol–disulphide exchange reaction. Even though the substitutions in insulin icodec significantly stabilise insulin against such degradation, some free B-chain is observed in plasma samples from minipigs and people with type 2 diabetes. In summary, we identify thiol–disulphide exchange reactions to be an important insulin clearance mechanism and find that stabilising insulin icodec towards this reaction significantly contributes to its long pharmacokinetic/pharmacodynamic profile

Discovery of the Once-Weekly Glucagon-Like Peptide‑1 (GLP-1) Analogue Semaglutide

Liraglutide is an acylated glucagon-like peptide-1 (GLP-1) analogue that binds to serum albumin <i>in vivo</i> and is approved for once-daily treatment of diabetes as well as obesity. The aim of the present studies was to design a once weekly GLP-1 analogue by increasing albumin affinity and secure full stability against metabolic degradation. The fatty acid moiety and the linking chemistry to GLP-1 were the key features to secure high albumin affinity and GLP-1 receptor (GLP-1R) potency and in obtaining a prolonged exposure and action of the GLP-1 analogue. Semaglutide was selected as the optimal once weekly candidate. Semaglutide has two amino acid substitutions compared to human GLP-1 (Aib⁸, Arg³⁴) and is derivatized at lysine 26. The GLP-1R affinity of semaglutide (0.38 ± 0.06 nM) was three-fold decreased compared to liraglutide, whereas the albumin affinity was increased. The plasma half-life was 46.1 h in mini-pigs following i.v. administration, and semaglutide has an MRT of 63.6 h after s.c. dosing to mini-pigs. Semaglutide is currently in phase 3 clinical testing

Small Angle X‑ray Scattering-Based Elucidation of the Self-Association Mechanism of Human Insulin Analogue Lys^B29(N^εω‑carboxyheptadecanoyl) des(B30)

Lys^B29(N^εω-carboxyheptadecanoyl) des­(B30) human insulin is an insulin analogue belonging to a class of analogues designed to form soluble depots <i>in subcutis</i> by self-association, aiming at a protracted action. On the basis of small angle X-ray scattering (SAXS) supplemented by a range of biophysical and structural methods (field flow fractionation, dynamic and multiangle light scattering, circular dichroism, size exclusion chromatography, and crystallography), we propose a mechanism for the self-association expected to occur upon subcutaneous injection of this insulin analogue. SAXS data provide evidence of the in solution structure of the self-associated oligomer, which is a long straight rod composed of “tense” state insulin hexamers (T₆-hexamers) as the smallest repeating unit. The smallest oligomer building block in the process is a T₆T₆-dihexamer. This tense dihexamer is formed by the allosteric change of the initial equilibrium between a proposed “relaxed” state R₆-hexamer and an R₃T₃T₃R₃-dihexamer. The allosteric change from relaxed to tense is triggered by removal of phenol, mimicking subcutaneous injection. The data hence provide the first unequivocal evidence of the mechanism of self-association for this type of insulin analogue

Author Correction: Molecular engineering of safe and efficacious oral basal insulin

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Molecular engineering of safe and efficacious oral basal insulin

Recently, the first orally-administered ultra-long acting insulin was shown to have clinical efficacy. Here, the authors report the molecular engineering, as well as the biological and pharmacological properties of these insulin analogues