Taspoglutide: a long acting human glucagon-like polypeptide-1 analogue

The correlations between steady-state concentration, duration of action and molecular weight of GLP-1RAs and their efficacy and gastrointestinal side effects in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

To assess the influence of steady-state concentration, duration of action and molecular weight of glucagon-like peptide-1 receptor (GLP-1RA) on efficacy and gastrointestinal (GI) side effects in patients with type 2 diabetes mellitus (T2DM).

METHODS

PubMed, EMBASE, the Cochrane Center Register of Controlled Trials for Studies and Clinicaltrial.gov were searched from inception to April 2022. Randomized controlled trials (RCTs) comparing GLP-1RA versus non-GLP-1RA agents in patients with T2DM were included. Sensitivity analyses on steady-state concentration, duration of action and molecular weight of GLP-1RA were conducted.

RESULTS

113 RCTs were included. Greater HbA1c reduction between GLP-1RA users versus non-GLP-1RA users was observed in the high-steady-state-concentration stratum and long-acting stratum compared with the low-steady-state-concentration stratum (P_{subgroup difference} = 0.0004) and short-acting stratum (P_{subgroup difference}<0.0001). The risk of GI adverse events in GLP-1RA users versus non-GLP-1RA users was decreased in the high-steady-state-concentration stratum, long-acting stratum and heavy-molecular-weight stratum compared with low-steady-state-concentration stratum (P_{subgroup difference}<0.0001), short-acting stratum (P_{subgroup difference} = 0.002) and light-molecular-weight stratum (P_{subgroup difference} = 0.0008).

CONCLUSION

GLP-1RA with high steady-state concentration and long duration of action showed better hypoglycemic effect. GLP-1RA with high steady-state concentration, long duration of action and heavy molecular weight was associated with lower risk of GI adverse events.

Glucagon-Like Peptide-1 and Its Class B G Protein-Coupled Receptors: A Long March to Therapeutic Successes

The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain-binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders.

Glucagon-like peptide-1 receptor agonists versus insulin glargine for type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonists are a new class of hypoglycemic drugs, including exenatide, liraglutide, albiglutide, lixisenatide, and taspoglutide. Insulin glargine is a standard agent used to supplement basal insulin in type 2 diabetes mellitus (T2DM).

OBJECTIVE

The aim of this study was to review the efficacy and safety profiles of GLP-1 receptor agonists versus insulin glargine in type 2 diabetic patients who have not achieved treatment goals with oral hypoglycemic agents.

METHODS

The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and the database of ongoing trials were searched from inception through April 2010. Additional data were sought from relevant Web sites, the American Diabetes Association, reference lists of included trials and related (systematic) reviews, and industry. Randomized controlled trials (RCTs) were selected if they were ≥3 months in duration, compared GLP-1 receptor agonists with insulin glargine in patients with T2DM, and included ≥1 of the following outcomes: mortality, complications of T2DM, glycemie control, weight, lipids, blood pressure, adverse effects, and health-related quality of life. Quasirandomized controlled trials were excluded. The quality of the eligible studies was assessed on the basis of the following aspects: randomization procedure, allocation concealment, blinding, incomplete outcome data (intent-to-treat [ITT] analysis), selective outcome reporting, and publication bias.

RESULTS

A total of 410 citations were retrieved; 5 multicenter RCTs that met the inclusion criteria were identified. They were all open-label designs with an insulin glargine arm, predefined outcomes reported, and ITT analysis. One trial had an unclear randomization procedure and allocation concealment. Publication bias was not able to be determined. No data wete found with regard to mortality or diabetes-associated complications, and few data were found on quality of life. The results of the metaanalysis suggest that insulin glargine was significantly better in reducing the fasting blood glucose (mean difference [MD] [95% CI], 1.31 [1.04 to 1.58]; P < 0.001), but exhibits greater incidence of nocturnal hypoglycemia (risk ratio [RR] [95% CI], 0.40 [0.23 to 0.71]; P = 0.002) and influenza (RR [95% CI], 0.56 [0.32 to 0.98]; P = 0.04). GLP-1 receptor agonists are more conducive to reducing weight (MD [95% CI], -3.96 [-5.14 to -2.77]; P < 0.001), postprandial blood glucose (after breakfast, P < 0.001; after dinner, P < 0.001), and LDL-C (MD [95% CI], -0.18 [-0.28 to -0.08]; P < 0.001), but have significantly more gastrointestinal adverse effects (eg, nausea/ vomiting, P < 0.001). There were no significant differences between GLP-1 receptor agonists and insulin glargine in reducing glycosylated hemoglobin (HbA1c) levels (MD [95% CI], -0.03 [-0.13 to 0.08]) and the overall incidence of hypoglycemia (RR [95% CI], 0.69 [0.42 to 1.14]).

CONCLUSIONS

Compared with insulin glargine, GLP-1 receptor agonists did not have a significant difference in regard to reducing HbA1c levels and they were significantly associated with decreased weight but increased gastrointestinal adverse events. It remains unclear whether GLP-1 receptor agonists influence mortality or diabetes-associated complications in patients with T2DM. More trials with longer follow-up are needed to determine the exact long-term efficacy and safety profiles of this new class of hypoglycemic drugs.

Impact of GLP-1 receptor agonists on major gastrointestinal disorders for type 2 diabetes mellitus: a mixed treatment comparison meta-analysis

AIM

We aimed to integrate evidence from all randomized controlled trials (RCTs) and assess the impact of different doses of exenatide or liraglutide on major gastrointestinal adverse events (GIAEs) in type 2 diabetes (T2DM).

METHODS

RCTs evaluating different doses of exenatide and liraglutide against placebo or an active comparator with treatment duration ≥4 weeks were searched and reviewed. A total of 35, 32 and 28 RCTs met the selection criteria evaluated for nausea, vomiting, and diarrhea, respectively. Pairwise random-effects meta-analyses and mixed treatment comparisons (MTC) of all RCTs were performed.

RESULTS

All GLP-1 dose groups significantly increased the probability of nausea, vomiting and diarrhea relative to placebo and conventional treatment. MTC meta-analysis showed that there was 99.2% and 85.0% probability, respectively, that people with exenatide 10 μg twice daily (EX10BID) was more vulnerable to nausea and vomiting than those with other treatments. There was a 78.90% probability that liraglutide 1.2 mg once daily (LIR1.2) has a higher risk of diarrhea than other groups. A dose-dependent relationship of exenatide and liraglutide on GIAEs was observed.

CONCLUSIONS

Our MTC meta-analysis suggests that patients should be warned about these GIAEs in early stage of treatment by GLP-1s, especially by EX10BID and LIR1.2, to promote treatment compliance.

Cardiovascular safety and glycemic control of glucagon-like peptide-1 receptor agonists for type 2 diabetes mellitus: a pairwise and network meta-analysis

AIMS

Integrating evidence from all randomized controlled trials (RCTs) of glucagon-like peptide-1 receptor agonists (GLP-1s) to assess the safety of cardiovascular disease (CVD) and efficacy of glycemic control.

METHODS

Besides performing pairwise meta-analysis, network meta-analysis of all RCTs was used to combine direct and indirect estimates of the effect of GLP-1 with placebo, active comparator drugs (ACD), or another GLP-1 agent with treatment duration ≥8 weeks in T2DM patients, 15,883 for CVD safety from 45 RCTs and 14,136 for glycemic control from 36 RCTs.

RESULTS

For CVD safety, both of the results from pairwise and network meta-analysis failed to demonstrate significant difference between any two comparators. For glycemic control, the effect of any GLP-1 was better than placebo, but no difference was found between GLP-1s. We also found that liraglutide was the only GLP-1 drug shown to be more effective on improving glycemic control than ACD and exenatide. The results based on direct or indirect estimates were similar for two outcomes.

CONCLUSION

Our network meta-analysis provides a complete picture of the associations between GLP-1s, ACD and placebo on CVD safety and glycemic control. The GLP-1s are promising candidates for the treatment of T2DM, but more long-term trials are needed to confirm potential CVD safety.

Novel therapeutics and targets for the treatment of diabetes

The microvascular complications of insufficiently controlled diabetes (neuropathy, retinopathy and nephropathy) and the marked increased risk of macrovascular events (e.g., stroke and myocardial infarction) have a dire impact on society in both human and economic terms. In Type 1 diabetes total β-cell loss occurs. In Type 2 diabetes, partial β-cell loss occurs before diagnosis, and the progressive β-cell loss during the life of the patient increases the severity of the disease. In patients with diabetes, increased insulin resistance in the muscle and liver are key pathophysiologic defects. In addition, defects in metabolic processes in the fat, GI tract, brain, pancreatic α-cells and kidney are detrimental to the overall health of the patient. This review addresses novel therapies for these deficiencies in clinical and preclinical evaluation, emphasizing their potential to address glucose homeostasis, β-cell mass and function, and the comorbidities of cardiovascular disease and obesity.

Efficacy and safety of taspoglutide monotherapy in drug-naive type 2 diabetic patients after 24 weeks of treatment: results of a randomized, double-blind, placebo-controlled phase 3 study (T-emerge 1)

OBJECTIVE

To evaluate the efficacy and safety of taspoglutide monotherapy in drug-naive patients with type 2 diabetes inadequately controlled.

RESEARCH DESIGN AND METHODS

In this 24-week double-blind, placebo-controlled, multicenter trial, 373 patients with type 2 diabetes naive to antihyperglycemic medication were randomized to weekly subcutaneous taspoglutide 10 or 20 mg or placebo.

RESULTS

HbA(1c) reductions from baseline were greater with taspoglutide 10 and 20 mg than placebo (least squares mean [SE] changes: -1.01% [0.07], -1.18% [0.06], and -0.09% [0.07], respectively; both P < 0.0001 vs. placebo). Decreases in bodyweight were greater with taspoglutide 10 mg (-1.45 kg [0.32]) and with 20 mg (-2.25 kg [0.30]) than placebo (-1.23 kg [0.31]; P = 0.61 and P = 0.02 for taspoglutide 10 and 20 mg vs. placebo, respectively). Gastrointestinal adverse events and injection site reactions were more common with taspoglutide than placebo.

CONCLUSIONS

In drug-naive patients, once-weekly taspoglutide improved glycemic control, reduced body weight, and was generally well tolerated.

Clinical Efficacy and Safety of Once-Weekly Glucagon-Like Peptide-1 Agonists in Development for Treatment of Type 2 Diabetes Mellitus in Adults

OBJECTIVE:

To review pharmacologic, pharmacokinetic, efficacy, and safety data of once-weekly glucagon-like peptide-1 (GLP-1) agonists exenatide long-acting release (LAR), albiglutide, and taspoglutide in treatment of type 2 diabetes mellitus (T2DM).

DATA SOURCES:

A MEDLINE search (1966-August 2011) was conducted using the following key words: type 2 diabetes mellitus, glucagon-like peptide-1 agonists once weekly, glucagon-like peptide-1 agonists, exenatide LAR, albiglutide, and taspoglutide.

STUDY SELECTION AND DATA EXTRACTION:

All articles published in English identified from the data sources were evaluated, prioritizing randomized controlled trials with human data. The references of published articles identified were examined for additional studies appropriate for the review.

DATA SYNTHESIS:

Native GLP-1 increases glucose-dependent insulin secretion, decreases glucagon secretion, and slows gastric emptying in healthy individuals, but these effects may be blunted in patients with T2DM. Because native GLP-1 is rapidly degraded by dipeptidyl peptidase-IV, it is not a practical treatment option. Currently, 2 GLP-1 receptor agonists have been approved by the Food and Drug Administration: exenatide twice daily and liraglutide once daily. Several additional GLP-1 agonists, including exenatide LAR, albiglutide, and taspoglutide, are in various stages of clinical trials and have been modified to increase their half-lives. These agents have shown significant improvements in hemoglobin A1c, fasting plasma glucose, and postprandial plasma glucose, as well as improvements in body weight, blood pressure, and lipid parameters. These agents allow for less-frequent dosing schedules, improved glycemic control throughout the day, and improved treatment satisfaction compared to some available agents. GLP-1 agonists have been well tolerated, with the most common adverse effects being gastrointestinal related, which occurred early in therapy but typically resolved after 4-8 weeks. The incidence of hypoglycemia was infrequent and mild during therapy.

CONCLUSIONS:

Once-weekly GLP-1 agonists provide similar glycemic control with weight reduction, as well as overall higher treatment satisfaction for patients because of their ease of use and need for less-frequent dosing compared to some available agents.

Glucagon-like peptide-1 analogues for Type 2 diabetes mellitus: current and emerging agents

Novel therapeutic options for type 2 diabetes mellitus based on the action of the incretin hormone glucagon-like peptide (GLP)-1 were introduced in 2005. As injectable GLP-1 receptor agonists acting on the GLP-1 receptor, exenatide and liraglutide are available in many countries. In type 2 diabetes treatment, incretin-based therapies are attractive and more commonly used because of their mechanism of action and safety profile. Stimulation of insulin secretion and inhibition of glucagon secretion by these agents occur in a glucose-dependent manner. Therefore, incretin-based therapies have no intrinsic risk for hypoglycaemia. Furthermore, GLP-1 receptor agonists allow weight loss and lower systolic blood pressure. This review gives a brief overview of the mechanism of action and summarizes the clinical data available on exenatide and liraglutide as established substances. It further highlights the clinical study data of exenatide once weekly as the first long-acting GLP-1 receptor agonist and covers other new long acting GLP-1 receptor agonists currently in clinical development. The placement of GLP-1 receptor agonists in the treatment algorithm of type 2 diabetes is discussed.

Novel GLP-1 receptor agonists for diabetes

INTRODUCTION

GLP-1 receptor agonists have been shown to be effective in the treatment of type 2 diabetes mellitus (T2DM). Although the first GLP-1 receptor agonist, exenatide, was approved in the mid-2000s, other agents with longer durations of action (that do not require twice-daily dosing) are now being developed. Indeed, liraglutide, a once-daily GLP-1 receptor agonist, was approved in 2010, and more recently, a once-weekly formulation of exenatide was approved in 2011. This review considers the mechanism of action of GLP-1 receptor agonists and considers the various agents in this class.

AREAS COVERED

The importance of GLP-1 itself in glycemic control and the use of GLP-1 receptor agonists in T2DM are discussed. An overview of the clinical development of the five GLP-1 receptor agonists (exenatide, liraglutide, lixisenatide, albiglutide and taspoglutide) since 2005 is provided and their mechanisms of action, efficacy in terms of glycemic control and weight loss, and tolerability are reviewed.

EXPERT OPINION

GLP-1 receptor agonists result in clinically meaningful weight loss in addition to their beneficial effects on glucose homeostasis. These agents provide substantial clinical benefits for patients compared with sulfonylureas or DPP-4 inhibitors and will, therefore, become one of the major therapeutic choices for patients with T2DM.

Incretin therapy--present and future

Although newer treatments for type 2 diabetes (T2D) patients have produced continual improvements in outcome, a large and growing population with prediabetes remains under-treated. In the last few years, incretin-based therapies have become an important treatment option for patients with T2D. There are two classes of incretin agents: the dipeptidyl peptidase-4 (DPP-4) inhibitors and the glucagon like peptide 1 (GLP-1) receptor agonists. The ultimate goal of agents within both of these classes is to increase GLP-1 signaling, which results in augmented glucose-induced insulin secretion, inhibition of glucagon secretion, and decreased appetite. This should result in improved regulation of glucose homeostasis. GLP-1 receptor agonists enable patients to achieve significant weight loss. In contrast, DPP-4 inhibitors result in a less dramatic increase in GLP-1 levels; therefore, they are weight neutral. Incretin therapies are currently recommended for use early in the treatment algorithm for T2D patients whose disease is not manageable by diet and exercise alone, but the potential for these agents may be farther reaching. Current studies are evaluating the potential benefits of combining incretin therapies with basal insulin to provide continuous glucose control before and after meals. In addition, these agents may be promising for patients with prediabetes since they effectively reduce glycosylated hemoglobin levels and fasting plasma glucose levels, enable weight control, and have the potential to preserve β-cell function. Clearly, all of these properties are desirable for patients with prediabetes.

Separation of exenatide analogue mono-PEGylated with 40 kDA polyethylene glycol by cation exchange chromatography

Random PEGylation usually resulted in product mixtures composed of mono-PEGylated isomers and multi-PEGylated attachments. Generally in PEGylation research, separation of the mono-PEGylated isomers was the prerequisite for finding the optimal PEGylation site. However, when peptides or proteins were PEGylated with polyethylene glycol as large as 40 kDA, the physicochemical properties like hydrophobicity and molecular size of the isomers would become too similar to make the routine separation methods, like RP-HPLC, size-exclusion chromatography, SDS-PAGE and capillary isoelectric focusing invalid. This article presented a useful method of successfully separating exenatide analogue (an incretin for diabetic therapy) isomers mono-PEGylated with 40 kDA polyethylene glycol by cation exchange chromatography, which would be a powerful tool for the PEGylation research.

Incretin-based therapy: a powerful and promising weapon in the treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a progressive multisystemic disease that increases significantly cardiovascular morbidity and mortality. It is associated with obesity, insulin resistance, beta-cell dysfunction, and hyperglucagonemia, the combination of which typically leads to hyperglycemia. Incretin-based treatment modalities, and in particular glucagon-like peptide 1 (GLP-1) receptor agonists, are able to successfully counteract several of the underlying pathophysiological abnormalities of T2DM. The pancreatic effects of GLP-1 receptor agonists include glucose-lowering effects by stimulating insulin secretion and inhibiting glucagon release in a strictly glucose-dependent manner, increased beta-cell proliferation, and decreased beta-cell apoptosis. GLP-1 receptors are widely expressed throughout human body; thus, GLP-1-based therapies exert pleiotropic and multisystemic effects that extend far beyond pancreatic islets. A large body of experimental and clinical data have suggested a considerable protective role of GLP-1 analogs in the cardiovascular system (decreased blood pressure, improved endothelial and myocardial function, functional recovery of failing and ischemic heart, arterial vasodilatation), kidneys (increased diuresis and natriuresis), gastrointestinal tract (delayed gastric emptying, reduced gastric acid secretion), and central nervous system (appetite suppression, neuroprotective properties). The pharmacologic use of GLP-1 receptor agonists has been shown to reduce bodyweight and systolic blood pressure, and significantly improve glycemic control and lipid profile. Interestingly, weight reduction induced by GLP-1 analogs reflects mainly loss of abdominal visceral fat. The critical issue of whether the emerging positive cardiometabolic effects of GLP-1 analogs can be translated into better clinical outcomes for diabetic patients in terms of long-term hard endpoints, such as cardiovascular morbidity and mortality, remains to be elucidated with prospective, large-scale clinical trials.

GLP-1 agonists and dipeptidyl-peptidase IV inhibitors

Novel therapeutic options for type 2 diabetes based on the action of the incretin hormone glucagon-like peptide-1 (GLP-1) were introduced in 2005. Incretin-based therapies consist of two classes: (1) the injectable GLP-1 receptor agonists solely acting on the GLP-1 receptor and (2) dipeptidyl-peptidase inhibitors (DPP-4 inhibitors) as oral medications raising endogenous GLP-1 and other hormone levels by inhibiting the degrading enzyme DPP-4. In type 2 diabetes therapy, incretin-based therapies are attractive and more commonly used due to their action and safety profile. Stimulation of insulin secretion and inhibition of glucagon secretion by the above-mentioned agents occur in a glucose-dependent manner. Therefore, incretin-based therapies have no intrinsic risk for hypoglycemias. GLP-1 receptor agonists allow weight loss; DPP-4 inhibitors are weight neutral. This review gives an overview on the mechanism of action and the substances and clinical data available.

The evolving place of incretin-based therapies in type 2 diabetes

Treatment options for type 2 diabetes based on the action of the incretin hormone glucagon-like peptide-1 (GLP-1) were first introduced in 2005. These comprise the injectable GLP-1 receptor agonists solely acting on the GLP-1 receptor on the one hand and orally active dipeptidyl-peptidase inhibitors (DPP-4 inhibitors) raising endogenous GLP-1 and other hormone levels by inhibiting the degrading enzyme DPP-4. In adult medicine, both treatment options are attractive and more commonly used because of their action and safety profile. The incretin-based therapies stimulate insulin secretion and inhibit glucagon secretion in a glucose-dependent manner and carry no intrinsic risk of hypoglycaemia. GLP-1 receptor agonists allow weight loss, whereas DPP-4 inhibitors are weight neutral. This review gives an overview of the mechanism of action and the substances and clinical data available.