Short-term effect of polyethylene glycol loxenatide on weight loss in overweight or obese patients with type 2 diabetes: An open-label, parallel-arm, randomized, metformin-controlled trial

Glucagon-like peptide-1 analogs: Miracle drugs are blooming?

Glucagon-like peptide-1 (GLP-1), secreted by L cells in the small intestine, assumes a central role in managing type 2 diabetes mellitus (T2DM) and obesity. Its influence on insulin secretion and gastric emptying positions it as a therapeutic linchpin. However, the limited applicability of native GLP-1 stems from its short half-life, primarily due to glomerular filtration and the inactivating effect of dipeptidyl peptidase-IV (DPP-IV). To address this, various structural modification strategies have been developed to extend GLP-1's half-life. Despite the commendable efficacy displayed by current GLP-1 receptor agonists, inherent limitations persist. A paradigm shift emerges with the advent of unimolecular multi-agonists, such as the recently introduced tirzepatide, wherein GLP-1 is ingeniously combined with other gastrointestinal hormones. This novel approach has captured the spotlight within the diabetes and obesity research community. This review summarizes the physiological functions of GLP-1, systematically explores diverse structural modifications, delves into the realm of unimolecular multi-agonists, and provides a nuanced portrayal of the developmental prospects that lie ahead for GLP-1 analogs.

Efficacy and safety of polyethylene glycol loxenatide in type 2 diabetic patients: a systematic review and meta-analysis of randomized controlled trials

Polyethylene glycol loxenatide (PEX168) is a novel glucagon-like peptide-1 receptor agonist with a longer half-life developed by modifying the chemical structure of exenatide. This study aims to assess the efficacy and safety of PEX168 and determine the best dose. We searched PubMed, Scopus, Cochrane Library, and Web of Science databases from inception to April 25, 2023, for randomized controlled trials (RCTs) comparing PEX168 therapy alone or in combination with metformin versus other therapies. We used the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) for continuous outcomes, both with 95% confidence intervals (CI). Six RCTs, including 1248 participants, were included. PEX168 added to metformin was significantly better than metformin alone regarding fasting blood glucose (MD = -1.20, 95% CI (-1.78,  - 0.62), p < 0.0001), HbA1c (MD = -1.01, 95% CI (-1.48,  - 0.53), p < 0.0001), and postprandial glycemia (MD = -1.94, 95% CI (-2.99,  - 0.90), p = 0.0003). Similarly, for glycemic control, PEX168 monotherapy was superior to placebo (P < 0.05). No significant effects were noticed in terms of triglycerides, low-density lipoprotein, or high-density lipoprotein (p > 0.05). Body weight was significantly reduced in obese diabetic patients receiving PEX168 compared to the control group (MD = -5.46, 95% CI (-7.90,  - 3.01), p < 0.0001) but not in non-obese patients (MD = 0.06, 95% CI (-0.47, 0.59), p = 0.83). People who received PEX168 alone or with metformin showed more common gastrointestinal adverse effects, especially nausea and vomiting (p < 0.05). PEX168 100, 200, and 300 ug monotherapy demonstrated comparable safety and diabetes control to metformin, but when combined with metformin, PEX168 100 and 200 ug showed significant effects on diabetes control; however, only the latter showed a significantly higher incidence of nausea and vomiting (p < 0.05). PEX168 could be a viable option for treating diabetic patients whose metformin control is inadequate or who cannot tolerate metformin. PEX168 at 100 ug in combination with metformin was found to be safe and more effective compared to metformin; however, due to the small number of trials included, these findings should be interpreted with caution, and additional trials are required.

Role of Novel Glucagon-like Peptide-1 Receptor Analogue Polyethylene Glycol Loxenatide in Type 2 Diabetes: A Systematic Review and Meta-analysis

Background

Polyethylene glycol loxenatide (peg-loxenatide) is a novel glucagon-like peptide-1 receptor agonist developed and available for clinical use in China. This meta-analysis was performed as no meta-analysis has analysed the efficacy and safety of peg-loxenatide in type 2 diabetes (T2DM).

Methods

Electronic databases were systematically reviewed for RCTs having patients living with T2DM receiving peg-loxenatide in treatment arm and placebo/any other diabetes medicine in control arm. The primary outcome was to evaluate changes in glycated haemoglobin. The secondary outcomes were to evaluate alterations in weight, blood pressure, fasting glucose, prandial glucose, lipids, and adverse events.

Results

Data from four trials (718 patients) were analysed. Over 12-24 weeks of clinical use, HbA1c was significantly lower in patients receiving standard-dose peg-loxenatide (100 mcg/week) {MD -0.95% [95% confidence interval (CI): -1.19 to -0.71]; P < 0.01; I2 = 76%} and high-dose peg-loxenatide (200 mcg/week) [MD -1.15% (95% CI: -1.47 to -0.82); P < 0.01; I2 = 90%], as compared to placebo. Standard-dose peg-loxenatide was not associated with increased occurrence of nausea [RR 2.87 (95% CI: 0.56 to 14.72); P = 0.21; I2 = 10%], vomiting [RR 4.73 (95% CI: 0.53 to 41.88); P = 0.16; I2 = 0%], and anorexia [RR 0.78 (95% CI: 0.18 to 3.28); P = 0.73; I2 = 0%]. Occurrence of nausea [RR 16.85 (95% CI: 3.89 to 72.92); P < 0.01; I2 = 10%], vomiting [RR 15.90 (95% CI: 2.99 to 84.55); P < 0.01; I2 = 0%], and anorexia [RR 3.85 (95% CI: 1.24 to 11.88); P = 0.02; I2 = 0%] was significantly higher with high-dose peg-loxenatide, as compared to placebo.

Conclusion

Peg-loxenatide (100 mcg/week) is the most appropriate dose for clinical use as it is associated with good glycaemic efficacy with minimal gastro-intestinal side effects.

Efficacy of polyethylene glycol loxenatide versus insulin glargine on glycemic control in patients with type 2 diabetes: a randomized, open-label, parallel-group trial

Objective: This trial aimed to evaluate the glycemic control of polyethylene glycol loxenatide measured with continuous glucose monitoring (CGM) in patients with type 2 diabetes mellitus (T2DM), with the hypothesis that participants given PEG-Loxe would spend more time in time-in-range (TIR) than participants were given insulin glargine after 24 weeks of treatment. Methods: This 24-week, randomized, open-label, parallel-group study was conducted in the Department of Endocrine and Metabolic Diseases, Longhu Hospital, Shantou, China. Participants with T2DM, who were ≥45 years of age, HbA1c of 7.0%-11.0%, and treated at least 3 months with metformin were randomized (1:1) to receive PEG-Loxe or insulin glargine. The primary endpoint was TIR (blood glucose range: 3.9-10.0 mmol/L) during the last 2 weeks of treatment (weeks 22-24). Results: From March 2020 to April 2022, a total of 107 participants with T2DM were screened, of whom 78 were enrolled into the trial (n = 39 per group). At the end of treatment (weeks 22-24), participants given PEG-Loxe had a greater proportion of time in TIR compared with participants given insulin glargine [estimated treatment difference (ETD) of 13.4% (95% CI, 6.8 to 20.0, p < 0.001)]. The tight TIR (3.9-7.8 mmol/L) was greater with PEG-Loxe versus insulin glargine, with an ETD of 15.6% (95% CI, 8.9 to 22.4, p < 0.001). The time above range (TAR) was significantly lower with PEG-Loxe versus insulin glargine [ETD for level 1: -10.5% (95% CI: -14.9 to -6.0), p < 0.001; ETD for level 2: -4.7% (95% CI: -7.9 to -1.5), p = 0.004]. The time below range (TBR) was similar between the two groups. The mean glucose was lower with PEG-Loxe versus insulin glargine, with an ETD of -1.2 mmol/L (95% CI, -1.9 to -0.5, p = 0.001). The SD of CGM glucose levels was 1.88 mmol/L for PEG-Loxe and 2.22 mmol/L for insulin glargine [ETD -0.34 mmol/L (95% CI: -0.55 to -0.12), p = 0.002], with a similar CV between the two groups. Conclusion: The addition of once-weekly GLP-1RA PEG-Loxe to metformin was superior to insulin glargine in improving glycemic control and glycemic variability evaluated by CGM in middle-aged and elderly patients with T2DM.