Novel exenatide analogs with peptidic albumin binding domains: potent anti-diabetic agents with extended duration of action.

The design, synthesis and pharmacology of novel long-acting exenatide analogs for the treatment of metabolic diseases are described. These molecules display enhanced pharmacokinetic profile and potent glucoregulatory and weight lowering actions compared to native exenatide. [Leu(14)]exenatide-ABD is an 88 residue peptide amide incorporating an Albumin Binding Domain (ABD) scaffold. [Leu(14)]exenatide-ABP is a 53 residue peptide incorporating a short Albumin Binding Peptide (ABP). [Leu(14)]exenatide-ABD and [Leu(14)]exenatide-ABP exhibited nanomolar functional GLP-1 receptor potency and were metabolically stable in vitro in human plasma and in a pancreatic digestive enzyme mixture. Both molecules displayed picomolar and nanomolar binding association with albumin across multiple species and circulating half lives of 16 and 11 hours, respectively, post a single IV dose in rats. Unlike exenatide, both molecules elicited robust glucose lowering when injected 1 day prior to an oral glucose tolerance test, indicative of their extended duration of action. [Leu(14)]exenatide-ABD was compared to exenatide in a Lep (ob/ob) mouse model of diabetes. Twice-weekly subcutaneously dosed [Leu(14)]exenatide-ABD displayed superior glucose lowering and weight loss in diabetic mice when compared to continuously infused exenatide at the same total weekly dose. A single oral administration of each molecule via an enteric coated capsule to cynomolgus monkeys showed superior pharmacokinetics for [Leu(14)]exenatide-ABD as compared to [Leu(14)]exenatide-ABP with detectable exposure longer than 14 days. These studies support the potential use of these novel long acting exenatide analogs with different routes of administration for the treatment of type 2 diabetes

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 <b>10</b> 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 <i>in vitro</i> and <i>in vivo</i> activities compared to those of a side-chain PEGylated phybrid <b>6</b>. In diet-induced obese (DIO) rats, the weight-loss efficacy of <b>10</b> was similar to that of a combination of PEG-parents <b>3</b> and <b>4</b>. A single dose of <b>10</b> elicited sustained body weight reduction in DIO rats for at least 21 days. Compound <b>10</b>’s terminal half-life of ∼27 h should translate favorably to weekly dosing in humans

Four-week chronic dosing of peptides in diabetic <i>Lep^ob/ob</i> Mice.

<p>(A) effects on HbA1c (B) effects on body weight and (C) effects on food intake. Vehicle (□), [Leu¹⁴]exenatide-ABD (▾) and exenatide (▪). Data are presented as mean ± SEM, n = 10. *p<0.05 vs. vehicle, #p<0.05 vs. exenatide infusion by ANOVA with Tukey’s test.</p

Improved Glucose Control and Reduced Body Weight in Rodents with Dual Mechanism of Action Peptide Hybrids

<div><p>Combination therapy is being increasingly used as a treatment paradigm for metabolic diseases such as diabetes and obesity. In the peptide therapeutics realm, recent work has highlighted the therapeutic potential of chimeric peptides that act on two distinct receptors, thereby harnessing parallel complementary mechanisms to induce additive or synergistic benefit compared to monotherapy. Here, we extend this hypothesis by linking a known anti-diabetic peptide with an anti-obesity peptide into a novel peptide hybrid, which we termed a phybrid. We report on the synthesis and biological activity of two such phybrids (AC164204 and AC164209), comprised of a glucagon-like peptide-1 receptor (GLP1-R) agonist, and exenatide analog, AC3082, covalently linked to a second generation amylin analog, davalintide. Both molecules acted as full agonists at their cognate receptors <i>in vitro</i>, albeit with reduced potency at the calcitonin receptor indicating slightly perturbed amylin agonism. In obese diabetic <i>Lep^ob/Lep</i>^<i>ob</i> mice sustained infusion of AC164204 and AC164209 reduced glucose and glycated haemoglobin (Hb_A1c) equivalently but induced greater weight loss relative to exenatide administration alone. Weight loss was similar to that induced by combined administration of exenatide and davalintide. In diet-induced obese rats, both phybrids dose-dependently reduced food intake and body weight to a greater extent than exenatide or davalintide alone, and equal to co-infusion of exenatide and davalintide. Phybrid-mediated and exenatide + davalintide-mediated weight loss was associated with reduced adiposity and preservation of lean mass. These data are the first to provide <i>in vivo</i> proof-of-concept for multi-pathway targeting in metabolic disease via a peptide hybrid, demonstrating that this approach is as effective as co-administration of individual peptides.</p> </div

Functional activity at the GLP-1 receptor.

<p>GLP-1 (7–36) (▪), [Leu¹⁴]exenatide-ABD (▾) and [Leu¹⁴]exenatide-ABP (▿). GLP-1 (7–36) was used as a reference standard in the assay. The assay was run in quadruplicates and data are presented as mean ± SD. Abbreviations: Fluorescence (F).</p

Binding Constants for Albumin Interactions at 25°C.

<p>The number in parentheses represents the standard deviation in the last significant digit.</p

PK profile of orally dosed peptides in monkeys.

<p>[Leu¹⁴]exenatide-ABD (▾) and [Leu¹⁴]exenatide-ABP (▿), n = 3. Data are presented as mean ± SEM.</p

<i>In Vitro</i> Activity, Metabolic Stability, and Plasma Glucose in OGTT.

<p>Stability results (measured as plasma AUC 0–5 h; pancreatin mix AUC 0–2 h)) are expressed as a percentage of peptide remaining versus stable control peptide ± SEM. Replicates within each assay n = 3, except for exenatide and [Leu¹⁴]exenatide-ABP where n = 2.</p

Names and Sequences of Compounds.

<p>Names and Sequences of Compounds.</p

PK profile of intravenously dosed peptides in rats and monkeys.

<p>(A) rats, n = 3–4 and (B) monkeys, n = 3. Exenatide (▪), [Leu¹⁴]exenatide-ABD (▾) and [Leu¹⁴]exenatide-ABP (▿). Data are presented as mean ± SEM.</p