Bifunctional PEGylated exenatide-amylinomimetic hybrids to treat metabolic disorders: an example of long-acting dual hormonal therapeutics.

Peptide hybrids (phybrids) comprising covalently linked peptide hormones can leverage independent biological pathways for additive or synergistic metabolic benefits. PEGylation of biologics offers enhanced stability, duration, and reduced immunogenicity. These two modalities can be combined to produce long-acting therapeutics with dual pharmacology and enhanced efficacy. Compound 10 is composed of an exenatide (AC2993) analogue, AC3174, and an amylinomimetic, davalintide (AC2307), with an intervening 40 kD PEG moiety. It displayed dose-dependent and prolonged efficacy for glucose control and body weight reduction in rodents with superior in vitro and in vivo activities compared to those of a side-chain PEGylated phybrid 6. In diet-induced obese (DIO) rats, the weight-loss efficacy of 10 was similar to that of a combination of PEG-parents 3 and 4. A single dose of 10 elicited sustained body weight reduction in DIO rats for at least 21 days. Compound 10's terminal half-life of ~27 h should translate favorably to weekly dosing in humans.

Native chemical ligation derived method for recombinant peptide/protein C-terminal amidation.

C-terminal amidation is often a requisite structural feature for peptide hormone bio-activity. We report a chemical amidation method that converts peptide/protein thioesters into their corresponding C-terminal amides. The peptide/protein thioester is treated with 1-(2,4-dimethoxyphenyl)-2-mercaptoethyl auxiliary (1b) in a native chemical ligation (NCL) reaction to form an intermediate, which upon removal of the auxiliary with TFA, yields the peptide/protein amide. We have demonstrated the general utility of the approach by successfully converting several synthetic peptide thioesters to peptide amides with high conversion rates. Preliminary results of converting a recombinant peptide thioester to its amide form are also reported.