ObjectiveA novel dual GIP and GLP-1 receptor agonist, LY3298176, was developed to determine whether the metabolic action of GIP adds to the established clinical benefits of selective GLP-1 receptor agonists in type 2 diabetes mellitus (T2DM).MethodsLY3298176 is a fatty acid modified peptide with dual GIP and GLP-1 receptor agonist activity designed for once-weekly subcutaneous administration. LY3298176 was characterised in vitro, using signaling and functional assays in cell lines expressing recombinant or endogenous incretin receptors, and in vivo using body weight, food intake, insulin secretion and glycemic profiles in mice.A Phase 1, randomised, placebo-controlled, double-blind study was comprised of three parts: a single-ascending dose (SAD; doses 0.25–8 mg) and 4-week multiple-ascending dose (MAD; doses 0.5–10 mg) studies in healthy subjects (HS), followed by a 4-week multiple-dose Phase 1 b proof-of-concept (POC; doses 0.5–15 mg) in patients with T2DM (ClinicalTrials.gov no. NCT02759107). Doses higher than 5 mg were attained by titration, dulaglutide (DU) was used as a positive control. The primary objective was to investigate safety and tolerability of LY3298176.ResultsLY3298176 activated both GIP and GLP-1 receptor signaling in vitro and showed glucose-dependent insulin secretion and improved glucose tolerance by acting on both GIP and GLP-1 receptors in mice. With chronic administration to mice, LY3298176 potently decreased body weight and food intake; these effects were significantly greater than the effects of a GLP-1 receptor agonist.A total of 142 human subjects received at least 1 dose of LY3298176, dulaglutide, or placebo. The PK profile of LY3298176 was investigated over a wide dose range (0.25–15 mg) and supports once-weekly administration. In the Phase 1 b trial of diabetic subjects, LY3298176 doses of 10 mg and 15 mg significantly reduced fasting serum glucose compared to placebo (least square mean [LSM] difference [95% CI]: −49.12 mg/dL [−78.14, −20.12] and −43.15 mg/dL [−73.06, −13.21], respectively). Reductions in body weight were significantly greater with the LY3298176 1.5 mg, 4.5 mg and 10 mg doses versus placebo in MAD HS (LSM difference [95% CI]: −1.75 kg [−3.38, −0.12], −5.09 kg [−6.72, −3.46] and −4.61 kg [−6.21, −3.01], respectively) and doses of 10 mg and 15 mg had a relevant effect in T2DM patients (LSM difference [95% CI]: −2.62 kg [−3.79, −1.45] and −2.07 kg [−3.25, −0.88], respectively.The most frequent side effects reported with LY3298176 were gastrointestinal (vomiting, nausea, decreased appetite, diarrhoea, and abdominal distension) in both HS and patients with T2DM; all were dose-dependent and considered mild to moderate in severity.ConclusionsBased on these results, the pharmacology of LY3298176 translates from preclinical to clinical studies. LY3298176 has the potential to deliver clinically meaningful improvement in glycaemic control and body weight. The data warrant further clinical evaluation of LY3298176 for the treatment of T2DM and potentially obesity.
Tirzepatide (LY3298176) is a dual GIP and GLP-1 receptor agonist under development for the treatment of type 2 diabetes mellitus (T2DM), obesity, and nonalcoholic steatohepatitis. Early phase trials in T2DM indicate that tirzepatide improves clinical outcomes beyond those achieved by a selective GLP-1 receptor agonist. Therefore, we hypothesized that the integrated potency and signaling properties of tirzepatide provide a unique pharmacological profile tailored for improving broad metabolic control. Here, we establish methodology for calculating occupancy of each receptor for clinically efficacious doses of the drug. This analysis reveals a greater degree of engagement of tirzepatide for the GIP receptor than the GLP-1 receptor, corroborating an imbalanced mechanism of action. Pharmacologically, signaling studies demonstrate that tirzepatide mimics the actions of native GIP at the GIP receptor but shows bias at the GLP-1 receptor to favor cAMP generation over β-arrestin recruitment, coincident with a weaker ability to drive GLP-1 receptor internalization compared with GLP-1. Experiments in primary islets reveal β-arrestin1 limits the insulin response to GLP-1, but not GIP or tirzepatide, suggesting that the biased agonism of tirzepatide enhances insulin secretion. Imbalance toward GIP receptor, combined with distinct signaling properties at the GLP-1 receptor, together may account for the promising efficacy of this investigational agent.
Aim: To assess the efficacy and tolerability of tirzepatide treatment using three different dose-escalation regimens in patients with type 2 diabetes. Materials and Methods:In this double-blind, placebo-controlled study, patients were randomized (1:1:1:1) to receive either once-weekly subcutaneous tirzepatide or placebo. The tirzepatide dose groups and dose-escalation regimens were: 12 mg (4 mg weeks 0-3; 8 mg weeks 4-7; 12 mg weeks 8-11), 15 mg-1 (2.5 mg weeks 0-1; 5 mg weeks 2-3; 10 mg weeks 4-7; 15 mg weeks 8-11) and 15 mg-2 (2.5 mg weeks 0-3; 7.5 mg weeks 4-7; 15 mg weeks 8-11). The primary objective was to compare tirzepatide with placebo in HbA1c change from baseline at 12 weeks.Results: Overall, 111 patients were randomized: placebo, 26; tirzepatide 12 mg, 29; tirzepatide 15 mg-1, 28; tirzepatide 15 mg-2, 28. The mean age was 57.4 years, HbA1c 8.4% and body mass index 31.9 kg/m 2 . At week 12, absolute HbA1c change from baseline (SE) was greater in the tirzepatide treatment groups compared with placebo (placebo, +0.2% [0.21]; 12 mg, −1.7% [0.19]; 15 mg-1, −2.0% [0.20]; 15 mg-2, −1.8% [0.19]). The incidence of nausea was: placebo, 7.7%; 12 mg group, 24.1%; 15 mg-1 group, 39.3%; 15 mg-2 group, 35.7%. Three patients discontinued the treatment because of adverse events, one from each of the placebo, 12 mg and 15 mg-1 groups.Conclusions: Tirzepatide treatment for 12 weeks resulted in clinically significant reductions in HbA1c. This suggests that lower starting doses and smaller dose increments are associated with a more favourable side effect profile.
Antibodies directed against tumor associated antigens are being increasingly used for detection and treatment of cancers; however, there is an incomplete understanding of the physiological determinants of antibody pharmacokinetics and tumor distribution. The purpose of this study is to (a) compare the plasma pharmacokinetics of T84.66, a monoclonal anti-CEA antibody directed against tumor associated carcinoembryonic antigen (CEA), in control and CEA expressing LS174T xenograft bearing mice, and (b) to develop a physiologically based pharmacokinetic (PBPK) model capable of integrating the influence of CEA and the IgG salvage receptor, FcRn, on T84.66 disposition. T84.66 pharmacokinetics were studied following i.v. administration (1, 10, 25 mg/kg) in control and xenograft bearing mice. In control mice, no significant differences in clearance were observed across the dose range studied. In mice bearing xenograft tumors, clearance was increased by four- to sevenfold, suggesting the presence of a "target mediated" elimination pathway. T84.66 plasma disposition was characterized with a PBPK model, and the model was applied to successfully predict antibody concentrations in tumor tissue. The PBPK model will be used to assist in the development of antibody-based targeting strategies for CEA-positive tumors.
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