Liraglutide - overview of the preclinical and clinical data and its role in the treatment of type 2 diabetes

Liraglutide innovations: a comprehensive review of patents (2014-2024)

Type-2 diabetes mellitus (T2DM) is a complicated long-term disorder associated with metabolism that is identified by insulin resistance, imbalance in glucose regulation and reduced secretion of insulin. GLP-1(Glucagon-like peptide-1) is an incretin mimetic that has excellent effects on the regulation of blood glucose levels and also the management of disorders associated with vital organs. GLP-1 agonist is an effective class of drug for the treatment of type-2 diabetes mellitus and associated complications. Liraglutide is one of the potent drugs of this class having similar effects as biological GLP-1. This review includes clinical trials and patents related to the pharmaceutical formulation, synthesis and biological action of liraglutide.

Effect of tirzepatide on glycaemic control and weight loss compared with other glucagon-like peptide-1 receptor agonists in Japanese patients with type 2 diabetes mellitus

AIM

To compare the therapeutic effects of glucose-dependent insulinotropic polypeptide (GIP)/ glucagon-like peptide-1 receptor agonists (GLP-1RAs) or GLP-1RAs in Japanese patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

We systematically searched PubMed, MEDLINE, EMBASE, and the Cochrane Library up to July 2023. Randomized controlled trials (RCTs) that compared GLP-1RAs or GIP/GLP-1RAs in Japanese patients with T2D were selected. A network meta-analysis was conducted to indirectly compare the treatments, focusing on efficacy in reducing glycated haemoglobin (HbA1c) levels and body weight (BW).

RESULTS

A total of 18 RCTs were included in this analysis. Tirzepatide 15 mg showed the most significant reduction in HbA1c levels and BW compared with subcutaneous semaglutide 1.0 mg and oral semaglutide 14 mg (HbA1c: mean difference [95% confidence interval] -0.52 [-0.96; -0.08] and - 1.23 [-1.64; -0.81]; BW: -5.07 [-8.28; -1.86] and -6.84 [-8.97; -4.71], respectively). Subcutaneous semaglutide showed a superior reduction in HbA1c compared with oral semaglutide. Both subcutaneous and oral semaglutide were more effective than conventional GLP-1RAs, such as dulaglutide, liraglutide and lixisenatide.

CONCLUSIONS

Among Japanese patients with T2D, tirzepatide showed the greatest effectiveness in reducing HbA1c levels and inducing weight loss. The study provides evidence to guide GLP-1RA treatment strategies in Japanese patients with T2D.

Emerging Role of GLP-1 Agonists in Obesity: A Comprehensive Review of Randomised Controlled Trials

Obesity is a chronic disease with high prevalence and associated comorbidities, making it a growing global concern. These comorbidities include type 2 diabetes, hypertension, ventilatory dysfunction, arthrosis, venous and lymphatic circulation diseases, depression, and others, which have a negative impact on health and increase morbidity and mortality. GLP-1 agonists, used to treat type 2 diabetes, have been shown to be effective in promoting weight loss in preclinical and clinical studies. This review summarizes numerous studies conducted on the main drugs in the GLP-1 agonists class, outlining the maximum achievable weight loss. Our aim is to emphasize the active role and main outcomes of GLP-1 agonists in promoting weight loss, as well as in improving hyperglycemia, insulin sensitivity, blood pressure, cardio-metabolic, and renal protection. We highlight the pleiotropic effects of these medications, along with their indications, contraindications, and precautions for both diabetic and non-diabetic patients, based on long-term follow-up studies.

Safety, pharmacokinetics, and pharmacodynamics of TG103, a novel long-acting GLP-1/Fc fusion protein after a single ascending dose in Chinese healthy subjects

BACKGROUND AND OBJECTIVE

TG103 is a novel GLP-1/Fc fusion protein, developed for the treatment of type 2 diabetes and obesity. This trial was designed to assess the safety and tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) profiles after single ascending dose of TG103 in healthy Chinese subjects.

METHOD

In this double-blind, randomized, placebo-controlled phase I study, Chinese healthy subjects were admitted consecutively to TG103 3 mg, 7.5 mg, 15 mg, and 22.5 mg group with 8 subjects per group and randomized in a 3:1 ratio to receive TG103 treatment or placebo. Following a single subcutaneous(s.c.) injections of TG103, safety and tolerability were evaluated and blood samples were collected for PK and PD analysis at the specified time-points.

RESULT

Overall, 32 healthy subjects were enrolled and completed the study. During the study, a total of 84 adverse effects (AEs) were reported in 25 subjects, all were mild or moderate and resolved spontaneously without intervention. The most common treatment related AEs in TG103 group were decreased appetite (41.7%), nausea, flatulence, elevated urinary β2-microglobulin, increased serum total bile acid (20.8% each), decreased high-density lipoprotein (16.7%), abdominal distension (12.5%). After a single s.c. administration of TG103 3-22.5 mg, the median T_max was 36∼48 hours, and mean t_1/2 was about 147.16∼184.72 hours. The mean C_max for each group was 94.35±52.19, 337.67±56.71, 757.67±206.99, 1236.33±666.25 ng/mL, with AUC_0-t of 14.93±7.67, 59.15±7.39, 91.79±20.41, 163.61±55.99 μg·h/mL, respectively. It showed a linear pharmacokinetic profile in the single dose of TG103 3 mg to 22.5 mg. Compared with placebo, fasting blood glucose decreased in all dose groups, most notably in the 15 mg group, which was consistent with the changes in blood glucose during OGTT, while 2-hour postprandial glucose decreased in all dose groups except 3 mg group.

CONCLUSION

TG103 offers a potential option for hypoglycemic therapy with good tolerability and safety.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03990090; registered 18 June, 2019.

Improved metabolic efficacy of a dual amylin and calcitonin receptor agonist when combined with semaglutide or empagliflozin

Pharmacotherapies for obesity and type 2 diabetes (T2D) are thought to bridge the gap between lifestyle modification and the weight loss obtained with bariatric surgery. Although the effect of monotherapies, namely amylin and glucagon-like peptide-1 receptor (GLP-1R) agonists, has shown great potential, combination therapy is now becoming a strategy to optimize efficacy for weight management while minimizing adverse effects. This study investigated a dual amylin and calcitonin receptor agonist (DACRA); KBP-066A in combination with the GLP-1R agonist semaglutide or the sodium-glucose co transporter-2 inhibitor (SGLT2i) empagliflozin for anti-obesity and anti-diabetic treatment. The effect of KBP-066A, semaglutide, and empagliflozin alone and in combination was studied with respect to their impact on body weight, food intake, and glucose metabolism in high-fat diet (HFD) and Zucker diabetic fatty (fa/fa) (ZDF) rats. Treatment with KBP-066A and semaglutide lowered body weight by 13% and 9.7%. In contrast, a combination of both KBP-066A + semaglutide reduced body weight by 21% in HFD rats demonstrating superiority compared to monotherapies alone. A combination of KBP-066A with semaglutide or empagliflozin significantly lowered fasting blood glucose, and HbA1C (%) levels in ZDF rats. The complementary action by KBP-066A to GLP-1R agonist and SGLT2i on BW, food intake and glucose control endorsed the potential of DACRAs as an add-on therapy to therapeutic options for T2D and obesity.

Liraglutide - Indian Experience

Liraglutide is an effective drug for the treatment of type 2 diabetes mellitus (T2DM). The aim of this review is to collate evidence on the real-world clinical effectiveness of liraglutide from the published Indian studies. A review of publications was conducted to identify observational studies that assessed the effectiveness of liraglutide among Indian T2DM. Total ten publications were retrieved and these observational studies are compared with the results of the liraglutide randomized controlled trial (RCT) program (Liraglutide Effect and Action in Diabetes [LEAD]). Liraglutide therapy demonstrated HbA1c reduction in the Indian population up to 2.26% and 2.54%, over 24 and 52 weeks, respectively. Among the LEAD trials, the HbA1c reduction at 24 weeks was maximum in LEAD-4 with 1.5% reduction at both doses used (1.2 and 1.8 mg) and up to 1.14% in LEAD-3 with a dose of 1.8 mg. The weight loss among Indian subjects was generally around 5 kg or more with maximum weight loss of 8.6 kg over 24 weeks. The maximal weight loss in LEAD studies was less than 3 kg with an exception of 3.24 kg in LEAD-6. In over 52 weeks of liraglutide therapy among Indian subjects, mean weight loss was 7.4 kg, which was 3.5 times more than of LEAD program. Two Indian observational studies also demonstrated significant weight loss among nondiabetic obese subjects at a much lower than that of 3 mg anti-obesity dose. Gastrointestinal (GI) events are the commonly reported adverse events with Indian studies as well as LEAD program. Liraglutide therapy produces better glycemic control and more weight loss among Indian T2DM subjects compared with RCTs conducted in western population with almost similar adverse consequences.

Recent updates on GLP-1 agonists: Current advancements & challenges

Glucagon-like peptide (GLP)-1 is an incretin hormone exhibiting several pharmacological actions such as neuroprotection, increased cognitive function, cardio-protection, decreased hypertension, suppression of acid secretion, increase in lyposis, and protection from inflammation. The most potent actions are glucose-dependent insulinotropic and glucagonostatic actions, stimulation of β-cell proliferation, enhanced insulin secretion and reduced weight gain in patients with type-2 diabetes pertaining to blood glucose control. Despite all these actions, its short half-life (around 2∼min) and degradation by a dipeptidyl peptidase-4 enzyme (DPP-4) limits the therapeutic utility of GLP1. In this review, we have discussed DPP IV-resistant analogs of GLP-1 currently present in clinical trials such as Exenatide, Liraglutide, Semaglutide, Efpeglenatide, Exenatide ER, Ittca 650 (Intarcia), Dulaglutide, Albiglutide, and Lixisenatide. Moreover, we have also discussed in detail the pharmacology, signaling mechanisms, and pharmacokinetic properties (Cmax, Tmax, T_1/2, Vd, and Bioavailability) of DPP IV-resistant analogs of (GLP-1). Interestingly, GLP-1 agonist drugs have shown better potential to treat type-2 diabetes mellitus (T2DM) as compared to currently used drugs in clinics without causing the side effects of hypoglycemia and weight gain.

Effects of Insulin Plus Glucagon-Like Peptide-1 Receptor Agonists (GLP-1RAs) in Treating Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

INTRODUCTION

Combination therapy with insulin and glucagon-like peptide-1 receptor agonists (GLP-1RAs) has already been proven an efficient treatment option for type 2 diabetes. This combination can effectively improve glycated hemoglobin levels, cause weight loss and reduce the dosage of insulin. In addition, it can also reduce the risk of hypoglycemia. Several randomized controlled trials have confirmed that this treatment may be just as effective for type 1 diabetes mellitus (T1DM) patients. The objective of this meta-analysis was to assess the effects and efficacy of the treatment on glycemic changes, weight loss and insulin dosage in type 1 diabetes mellitus patients.

METHODS

We searched Embase, PubMed and Cochrane for randomized controlled trials (no time restrictions) that investigated combined insulin and GLP-1 treatment. The main endpoints were measurements of glycated hemoglobin and changes in the weight and the dosage of insulin.

RESULTS

In total, 1093 were studies identified, and 7 studies were included in our meta-analysis. GLP-1 agonist and insulin combination therapy led to greater reductions in HbA1c levels [P = 0.03; mean difference -0.21; 95% confidence intervals (CI) (-0.40, 0.02)] and weight [P < 0.05; -3.53 (-4.86, 2.19)] compared to control treatments. The combination therapy did not significantly influence the daily weight-adjusted total insulin dose [P = 0.05; -0.11 (-0.23, 0)], but it did reduce the daily weight-adjusted bolus insulin dose [P = 0.001; -0.06 (-0.1, 0.02)].

CONCLUSION

Our meta-analysis supports the use of a combined therapeutic regimen of insulin and GLP-1RAs for treating patients with T1DM. Combination therapy with GLP-1 and insulin could achieve an ideal treatment effect on glycemic control, weight loss and bolus insulin dose in patients with T1DM.

Short-term effectiveness of low dose liraglutide in combination with metformin versus high dose liraglutide alone in treatment of obese PCOS: randomized trial

BACKGROUND

Liraglutide 3 mg was recently approved as an anti-obesity drug. Metformin is weight neutral, yet it could enhance the therapeutic index of GLP-1 agonist. We compared weight-lowering potential of liraglutide 1.2 mg in combination with metformin to liraglutide 3 mg monotherapy in obese PCOS.

METHODS

Thirty obese women with PCOS (aged 33.1 ± 6.1 years, BMI 38.3 ± 5.4 kg/m²) were randomized to combination (COMBO) of metformin (MET) 1000 mg BID and liraglutide 1.2 mg QD (N = 15) or liraglutide 3 mg (LIRA3) QD alone (N = 15) for 12 weeks. The primary outcome was change in anthropometric measures of obesity.

RESULTS

Both treatments led to significant weight loss (-3.6 ± 2.5 kg, p = 0.002 in COMBO vs -6.3 ± 3.7 kg, p = 0.001 in LIRA3). BMI and waist circumference reduction in LIRA3 was greater than in COMBO (-2.2 ± 1.3 vs -1.3 ± 0.9 kg/m²_, p = 0.05 and -4.2 ± 3.4 vs -2.2 ± 6.2 cm, p = 0.014, respectively). Both interventions resulted in a significant decrease of post-OGTT glucose levels. COMBO significantly reduced total testosterone and was associated with less nausea.

CONCLUSIONS

Short-term interventions with COMBO and LIRA3 both led to significant improvement of measures of obesity in obese PCOS, LIRA3 being superior to COMBO. However, COMBO further improved androgen profile beyond weight reduction and was associated with better tolerability.

TRIAL REGISTRATION

The study was retrospectively registered with ClinicalTrials.gov ( NCT02909933 ) on 16^th of September 2016.

Efficacy and safety of liraglutide compared to sulphonylurea during Ramadan in patients with type 2 diabetes (LIRA-Ramadan): a randomized trial

AIMS

Compare effects of liraglutide 1.8 mg and sulphonylurea, both combined with metformin, on glycaemic control in patients with type 2 diabetes (T2D) fasting during Ramadan.

MATERIALS AND METHODS

In this up to 33-week, open-label, active-controlled, parallel-group trial, adults [glycated haemoglobin (HbA1c) 7%-10% (53-86 mmol/mol); body mass index ≥20 kg/m(2) ; intent to fast] were randomized (1:1) ≥10 weeks before Ramadan to either switch to once-daily liraglutide (final dose 1.8 mg) or continue pre-trial sulphonylurea at maximum tolerated dose, both with metformin.

PRIMARY ENDPOINT

change in fructosamine, a validated marker of short-term glycaemic control, during Ramadan.

RESULTS

Similar reductions in fructosamine levels were observed for both groups during Ramadan [liraglutide (-12.8 µmol/L); sulphonylurea (-16.4 µmol/L); estimated treatment difference (ETD) 3.51 µmol/L (95% CI: -5.26; 12.28); p = 0.43], despite lower fructosamine levels in the liraglutide group at start of Ramadan. Fewer documented symptomatic hypoglycaemic episodes were reported in liraglutide-treated (2%, three subjects) versus sulphonylurea-treated patients (11%, 18 subjects). No severe hypoglycaemic episodes were reported by either group. Body weight decreased more during Ramadan with liraglutide (ETD: -0.54 kg; 95% CI: -0.94;-0.14; p = 0.0091). The proportion of patients reporting adverse events was similar between groups. Liraglutide led to greater HbA1c reduction [ETD: -0.59% (-6.40 mmol/mol), 95% CI: -0.79; -0.38%; -8.63; -4.17 mmol/mol; p < 0.0001].

CONCLUSIONS

Despite lower fructosamine levels and body weight at the beginning of Ramadan, use of liraglutide showed similar glycaemic improvements, fewer hypoglycaemic episodes and greater body weight reduction compared with sulphonylurea. LIRA-Ramadan provides evidence for liraglutide being safe and efficacious for management of T2D during Ramadan fasting.

Clinical Effectiveness of Liraglutide in Type 2 Diabetes Treatment in the Real-World Setting: A Systematic Literature Review

INTRODUCTION

In clinical trials, liraglutide has proven to be an effective drug for the treatment of type 2 diabetes mellitus (T2DM). The real-world effectiveness of liraglutide has been investigated in numerous studies. The aim of this systematic literature review is to collate evidence on the real-world clinical effectiveness of liraglutide.

METHODS

A review of publications from Medline, EMBASE, the Cochrane Library, and conference proceedings was conducted to identify observational studies that assessed the clinical effectiveness of liraglutide in real-world clinical practice. This review was conducted according to the National Institute of Health and Care Excellence (NICE) guidance. No language or time limits were applied, except to the conference proceedings (2013-2015). Endpoints for data extraction were decided a priori. Study quality appraisal was done for full-text journal articles.

RESULTS

Of 124 publications included in the review, 43 were full-text articles. Liraglutide significantly reduces glycated hemoglobin (HbA1c) within 6 months of initiating treatment (mean change in HbA1c from baseline: -0.9% to -2.2%; HbA1c <7.0%: 29.5-65.0%). The NICE composite endpoint (HbA1c reduction ≥1% and weight reduction ≥3%) was met in 16.9-47.0% of patients with liraglutide treatment. Liraglutide therapy led to a mean change in absolute weight from baseline of -1.3 to -8.65 kg. Liraglutide treatment was well tolerated in patients with T2DM. The rate of occurrence of hypoglycemia with liraglutide monotherapy was ≤0.8%. Hypoglycemia was more common in patients taking antidiabetic medications (0.0-15.2%) together with liraglutide. The beneficial glycemic and weight effect of liraglutide therapy in patients with T2DM was maintained for at least 12 months.

CONCLUSION

Evidence from observational studies reflecting real-world clinical practice demonstrates that liraglutide therapy improves glycemic control with a low risk of hypoglycemia, and is associated with significant weight loss in patients with T2DM. These observations are consistent with clinical trial findings.

FUNDING

Novo Nordisk A/S, Søborg, Denmark.

Unimolecular Polypharmacy for Treatment of Diabetes and Obesity

Many complex diseases have historically proven to be defiant to the best mono-therapeutic approaches. Several examples of combination therapies have largely overcome such challenges, notably for the treatment of severe hypertension and tuberculosis. Obesity and its consequences, such as type 2 diabetes, have proven to be equally resistant to therapeutic approaches based on single medicines. Proper management of type 2 diabetes often requires adjunctive medications, and the recent registration of a few compound mixtures has set the precedent for combinatorial treatment of obesity. On the other hand, double or triple therapeutic combinations are more difficult to advance to regulatory approval than single molecules. More recently, several classes of novel unimolecular combination therapeutics have emerged with superior efficacy than currently prescribed options and pose the potential to reverse obesity and type 2 diabetes. Here, we summarize the discovery, pre-clinical validation, and first clinical test of such peptide hormone poly-agonist drug candidates.

Effect of duodenal glucose load on blood pressure in type 2 diabetes

Postprandial hypotension occurs frequently in diabetes. We show in 9 type 2 patients, that the fall in systolic blood pressure is greater in response to intraduodenal glucose infused at 4 kcal/min than 2 kcal/min, implying that strategies to slow gastric emptying may be effective in the management of postprandial hypotension.

Metformin as an initial adjunct to low-dose liraglutide enhances the weight-decreasing potential of liraglutide in obese polycystic ovary syndrome: Randomized control study

Liraglutide (LIRA) treatment is associated with the dose-dependent reduction of weight. Higher doses are more effective than lower doses, although higher doses are also more poorly tolerated. Metformin may enhance the weight-lowering potential of LIRA via the stimulatory modulation of incretin in addition to its direct beneficial effects in PCOS. The aim of the present study was to evaluate whether metformin as an adjunct to low-dose LIRA affects body weight with increased efficacy compared with low-dose LIRA alone in obese patients with PCOS. In a 12-week study, 44 obese women with PCOS were randomly offered either combined treatment (COMBO) with 1,000 mg metformin twice a day and 1.2 mg LIRA once a day, or treatment with 1.2 mg LIRA alone. The primary outcome of treatment was an alteration in the levels of obesity. A total of 43 patients [aged 30.3±4.4 years; body mass index (BMI) 37.2±4.5 kg/m²; mean ± standard deviation] completed the study. The subjects treated with COMBO lost on average 6.2±2.4 kg compared with a 3.8±3.5 kg weight loss in the patients treated with LIRA alone (P=0.024). The BMI decreased by 2.2±0.8 kg/m² in patients treated with COMBO and by 1.4±1.2 kg/m² in patients treated with LIRA alone (P=0.024). A clinically significant ≥5% weight reduction was achieved in 59.1% of patients treated with COMBO and 42.9% of patients treated with LIRA alone. Reductions in glucose levels following oral glucose tolerance testing, as well as in androstenedione levels in the COMBO group were significantly greater compared with those in the LIRA group. The side effects were mild and transient in the two treatment groups. A combination of metformin and low-dose LIRA was more effective than low-dose LIRA alone in reducing body weight in obese patients with PCOS.

Efficacy and Safety of Liraglutide Versus Placebo as Add-on to Glucose-Lowering Therapy in Patients With Type 2 Diabetes and Moderate Renal Impairment (LIRA-RENAL): A Randomized Clinical Trial

OBJECTIVE

Renal impairment in type 2 diabetes limits available glucose-lowering treatment options. This trial was conducted to establish the efficacy and safety of liraglutide as an add-on to existing glucose-lowering medications in patients with inadequately controlled type 2 diabetes and moderate renal impairment.

RESEARCH DESIGN AND METHODS

In this 26-week, double-blind trial, 279 patients with HbA1c 7-10%, BMI 20-45 kg/m(2), and moderate renal impairment (estimated glomerular filtration rate [eGFR] 30-59 mL/min/1.73 m(2); MDRD) were randomized (1:1) to once-daily liraglutide 1.8 mg (n = 140) or placebo (n = 139).

RESULTS

The estimated treatment difference in HbA1c from baseline to week 26 was -0.66% (-7.25 mmol/mol) (95% CI -0.90 to -0.43 [-9.82 to -4.69]), P < 0.0001). Fasting plasma glucose decreased more with liraglutide (-1.22 mmol/L [-22.0 mg/dL]) than with placebo (-0.57 mmol/L [-10.3 mg/dL], P = 0.036). There was a greater reduction in body weight with liraglutide (-2.41 kg) than with placebo (-1.09 kg, P = 0.0052). No changes in renal function were observed (eGFR relative ratio to baseline: -1% liraglutide, +1% placebo; estimated treatment ratio [ETR] 0.98, P = 0.36). The most common adverse events were gastrointestinal (GI) adverse effects (liraglutide, 35.7%; placebo, 17.5%). No difference in hypoglycemic episodes was observed between treatment groups (event rate/100 patient-years of exposure: liraglutide, 30.47; placebo, 40.08; P = 0.54). The estimated ratio to baseline for lipase was 1.33 for liraglutide and 0.97 for placebo (ETR 1.37, P < 0.0001).

CONCLUSIONS

Liraglutide did not affect renal function and demonstrated better glycemic control, with no increase in hypoglycemia risk but with higher withdrawals due to GI adverse events than placebo in patients with type 2 diabetes and moderate renal impairment.

Combination therapy with liraglutide and insulin in Japanese patients with type 2 diabetes: A 36-week, randomized, double-blind, parallel-group trial

AIMS/INTRODUCTION

To assess efficacy and safety of liraglutide in combination with insulin compared with insulin monotherapy in Japanese patients with type 2 diabetes.

MATERIALS AND METHODS

This was a 36-week, multicenter, double-blind, parallel-group trial, where patients on stable insulin therapy (basal/premixed/basal-bolus) were randomized 1:1 to additional liraglutide 0.9 mg/day (n = 127) or placebo (n = 130). The insulin dose was fixed for 16 weeks, and titrated based on self-measured plasma glucose thereafter. The primary end-point was change in glycosylated hemoglobin after 16 weeks.

RESULTS

Superiority of liraglutide plus insulin versus insulin monotherapy was confirmed based on estimated mean difference in glycosylated hemoglobin after 16 weeks of -1.30% (-14 mmol/mol; 95% confidence interval -1.47 to -1.13 [-16, -12]; P < 0.0001). Statistical significance was maintained to week 36. More patients on liraglutide achieved a glycosylated hemoglobin target of <7.0% (<53 mmol/mol) at week 16 (estimated odds ratio 50.57; 95% confidence interval 16.59 to 154.16; P < 0.0001). Improvements in seven-point self-measured plasma glucose and fasting plasma glucose were significantly greater with liraglutide than the placebo at week 16. Insulin dose after 36 weeks was lower with liraglutide than the placebo (estimated treatment ratio: 0.82 [95% confidence interval 0.76-0.90; P < 0.0001]). Occurrence of adverse events was similar in the two groups (85.8 and 81.5%, respectively); most were mild in severity. There were no significant differences in the number of hypoglycemic episodes during the 36 weeks.

CONCLUSIONS

Adding liraglutide to insulin results in superior glycemic control compared with insulin alone in Japanese patients with type 2 diabetes, and is generally well tolerated.

Emerging opportunities for the treatment of metabolic diseases: Glucagon-like peptide-1 based multi-agonists

Obesity is a pathogenic gateway to the metabolic syndrome and the complications thereof, thus interventions aimed at preventing or reversing the metabolic derangements underlying obesity hold great therapeutic promise. However, the complexity of energy balance regulation, combined with the heterologous pathophysiology of human obesity, renders effective medicinal intervention very difficult. Indeed, the search for the silver bullet in anti-obesity medicines has been laden with drugs of underwhelming efficacy and unacceptable side effects. This can partly be the consequence that many of these drug interventions have been historically directed at single molecular targets. New multi-molecular combination therapies have shown promising clinical outcomes in terms of weight loss, yet multi-functional single molecules may offer even more advantages than adjunctive co-treatments. Single molecules with integrated activities derived from multiple hormones involved in the physiological control of metabolism have emerged as one of the more promising candidates for reversing obesity. The inclusion of glucagon-like peptide-1 (GLP-1) as one of the constituents is a unifying factor amongst the majority of these unimolecular multi-agonists. The scope of this review is to summarize the current preclinical and clinical landscape of GLP-1-based therapies, focusing on combinatorial therapies with a particular emphasis on single molecule compounds displaying multi-agonist properties.

Twelve-Week Treatment With Liraglutide as Add-on to Insulin in Normal-Weight Patients With Poorly Controlled Type 1 Diabetes: A Randomized, Placebo-Controlled, Double-Blind Parallel Study

OBJECTIVE

This study investigated the efficacy and safety of once-daily liraglutide 1.2 mg versus placebo as add-on to insulin treatment in normal-weight patients with poorly controlled type 1 diabetes.

RESEARCH DESIGN AND METHODS

In a randomized (1:1), double-blind, placebo-controlled design, 40 patients with type 1 diabetes (HbA1c ≥8% [64 mmol/mol]) received once-daily liraglutide 1.2 mg or placebo for 12 weeks. Continuous glucose monitoring was performed before and at the end of treatment. The primary end point was change in HbA1c. Secondary end points included change in insulin dose, weight, glycemic excursions, heart rate, and blood pressure.

RESULTS

Baseline HbA1c was similar in the liraglutide and placebo group (8.8 ± 0.2 and 8.7 ± 0.1% [72.5 ± 2.2 and 71.8 ± 1.5 mmol/mol]). Change in HbA1c from baseline was -0.6 ± 0.2% (-6.22 ± 1.71 mmol/mol) with liraglutide and -0.5 ± 0.2% (-5.56 ± 1.67 mmol/mol) with placebo (P = 0.62). Variation in glycemic excursions did not change in either group. Change in body weight was -3.13 ± 0.58 and +1.12 ± 0.42 kg (P < 0.0001) with liraglutide and placebo, respectively. The bolus insulin dose decreased in liraglutide-treated patients and did not change with placebo treatment (4.0 ± 1.3 vs. 0.0 ± 1.0 IU, P = 0.02). Heart rate increased within the liraglutide group (P = 0.04) but not compared with placebo, whereas mean systolic blood pressure decreased compared with placebo (between-group difference 3.21 mmHg [95% CI -8.31 to 1.90], P = 0.04). Liraglutide was more frequently associated with gastrointestinal adverse effects. The incidence of hypoglycemia did not differ between groups.

CONCLUSIONS

Liraglutide significantly reduces body weight and insulin requirements but has no additional effect on HbA1c in normal-weight patients with type 1 diabetes inadequately controlled on insulin alone.

Incretin-based therapies for obesity treatment

Currently, obesity and its associated complications are considered major public health problems worldwide. Because the causes are multifactorial and complex, different treatment methods are used, which include diet and exercise, as well as the use of drugs, although they can have adverse side effects. A new target for the treatment of obesity may be the incretin system, which consists of hormones that seem to contribute to weight loss. In this sense, some studies have shown a relationship between weight loss and drugs related to incretin system, including glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors. The objective of this review is to summarize the association between the incretin system and obesity treatment.

Effects of exogenous glucagon-like peptide-1 on blood pressure, heart rate, gastric emptying, mesenteric blood flow and glycaemic responses to oral glucose in older individuals with normal glucose tolerance or type 2 diabetes

AIMS/HYPOTHESIS

A postprandial fall in BP occurs frequently in older individuals and in patients with type 2 diabetes. The magnitude of this decrease in BP is related to the rate of gastric emptying (GE). Intravenous administration of glucagon-like peptide-1 (GLP-1) attenuates the hypotensive response to intraduodenal glucose in healthy older individuals. We sought to determine the effects of exogenous GLP-1 on BP, GE, superior mesenteric artery (SMA) flow and glycaemic response to oral ingestion of glucose in healthy older individuals and patients with type 2 diabetes.

METHODS

Fourteen older volunteers (six men, eight women; age 72.1 ± 1.1 years) and ten patients with type 2 diabetes (six men, four women; age 68.7 ± 3.4 years; HbA1c 6.6 ± 0.2% [48.5 ± 2.0 mmol/mol]; nine with blood glucose managed with metformin, two with a sulfonylurea and one with a dipeptidyl-peptidase 4 inhibitor) received an i.v. infusion of GLP-1 (0.9 pmol kg(-1) min(-1)) or saline (154 mmol/l NaCl) for 150 min (t = -30 min to t = 120 min) in randomised order. At t = 0 min, volunteers consumed a radiolabelled 75 g glucose drink. BP was assessed with an automated device, GE by scintigraphy and SMA flow by ultrasonography. Blood glucose and serum insulin were measured.

RESULTS

GLP-1 attenuated the fall in diastolic BP after the glucose drink in older individuals (p < 0.05) and attenuated the fall in systolic and diastolic BP in patients with type 2 diabetes (p < 0.05). GE was faster in patients with type 2 diabetes than in healthy individuals (p < 0.05). In both groups, individuals had slower GE (p < 0.001), decreased SMA flow (p < 0.05) and a lower degree of glycaemia (p < 0.001) when receiving GLP-1.

CONCLUSIONS/INTERPRETATION

Intravenous GLP-1 attenuates the hypotensive response to orally administered glucose and decreases SMA flow, probably by slowing GE. GLP-1 and 'short-acting' GLP-1 agonists may be useful in the management of postprandial hypotension.

Prophylactic liraglutide treatment prevents amyloid plaque deposition, chronic inflammation and memory impairment in APP/PS1 mice

Type 2 diabetes is a risk factor for Alzheimer's disease (AD). Previously, we have shown that the diabetes drug liraglutide is protective in middle aged and in old APP/PS1 mice. Here, we show that liraglutide has prophylactic properties. When injecting liraglutide once-daily ip. in two months old mice for 8 months, the main hallmarks of AD were much reduced. Memory formation in object recognition and Morris water maze were normalised and synapse loss and the loss of synaptic plasticity was prevented. In addition, amyloid plaque load, including dense core congophilic plaques, was much reduced. Chronic inflammation (activated microglia) was also reduced in the cortex, and neurogenesis was enhanced in the dentate gyrus. The results demonstrate that liraglutide may protect from progressive neurodegeneration that develops in AD. The drug is currently in clinical trials in patients with AD.

Liraglutide is effective and well tolerated in combination with an oral antidiabetic drug in Japanese patients with type 2 diabetes: A randomized, 52-week, open-label, parallel-group trial

Introduction

The safety and efficacy of liraglutide in combination with an oral antidiabetic drug (OAD) compared with combination of two OADs were assessed in Japanese patients with type 2 diabetes.

Materials and Methods

This was a 52‐week, open‐label, parallel‐group trial in which patients whose type 2 diabetes was inadequately controlled with a single OAD (glinide, metformin, α‐glucosidase inhibitor or thiazolidinedione) were randomized 2:1 to either pretrial OAD in combination with liraglutide 0.9 mg/day (liraglutide group; n = 240) or pretrial OAD in combination with an additional OAD (additional OAD group; n = 120). The primary outcome measure was the incidence of adverse events (AEs).

Results

Overall, 86.3% of patients in the liraglutide group and 85.0% of patients in the additional OAD group experienced AEs; these were similar in nature and severity. Adverse event rates were 361 and 331 per 100 patient‐years of exposure, respectively. Confirmed hypoglycemia was rare (seven episodes in two patients on liraglutide, and two in two patients on additional OAD). There were no reported pancreatitis events, and no unexpected safety signals were identified. Mean reductions in glycosylated hemoglobin were significantly greater in the liraglutide group than the additional OAD group [estimated mean treatment difference −0.27% (95% confidence interval (CI) −0.44, −0.09; P = 0.0026)]; reductions in mean fasting plasma glucose levels were also greater with liraglutide [estimated mean difference −5.47 mg/dL (−0.30 mmol/L; 95% CI: −10.83, −0.10; P = 0.0458)].

Conclusions

Liraglutide was well tolerated and effective as combination therapy with an OAD in Japanese patients with type 2 diabetes.

Add-On Treatment with Liraglutide Improves Glycemic Control in Patients with Type 2 Diabetes on Metformin Therapy

BACKGROUND

Liraglutide is a glucagon-like peptide-1 receptor analog recently approved for the treatment of type 2 diabetes mellitus (T2DM). We aimed to assess the efficacy and safety of liraglutide versus glimepiride, as adjunct treatments to metformin, in achieving glycemic control in Italian patients with T2DM uncontrolled by metformin alone.

SUBJECTS AND METHODS

One hundred seventy-nine diabetes patients treated with metformin plus liraglutide (1.8 mg) or glimepiride (4 mg) were retrospectively assessed at baseline, during, and after 18 months of continuous therapy.

RESULTS

Treatment with liraglutide resulted in mean decreases in hemoglobin A1c (HbA1c) of -1.4%, when compared with glimepiride (-0.4%) (P < 0.001), and was followed by a significant reduction (P < 0.001) in fasting plasma glucose. Variations in HbA1c occurred independently from weight loss, which was significantly reduced (P < 0.001) in liraglutide-treated patients. The percentage of subjects reaching HbA1c levels below 7% or ≤ 6.5% was significantly different between the two treated groups (P < 0.001). Treatment with liraglutide reduced waist circumference (WC) (P < 0.001) and decreased both systolic and diastolic blood pressure (BP) (P < 0.001). It is interesting that the study also showed the impact of female gender in predicting a better glycemic response to liraglutide (P = 0.028).

CONCLUSIONS

Liraglutide was more effective than glimepiride in reducing HbA1c levels in treated patients with T2DM. This was evident in both genders, but particularly in women. Furthermore, liraglutide reduced body weight, WC, and BP, which are critical risk factors for cardiovascular disease.

Gut-brain connection: The neuroprotective effects of the anti-diabetic drug liraglutide

Long-acting glucagon-like peptide-1 (GLP-1) analogues marketed for type 2 diabetes (T2D) treatment have been showing positive and protective effects in several different tissues, including pancreas, heart or even brain. This gut secreted hormone plays a potent insulinotropic activity and an important role in maintaining glucose homeostasis. Furthermore, growing evidences suggest the occurrence of several commonalities between T2D and neurodegenerative diseases, insulin resistance being pointed as a main cause for cognitive decline and increased risk to develop dementia. In this regard, it has also been suggested that stimulation of brain insulin signaling may have a protective role against cognitive deficits. As GLP-1 receptors (GLP-1R) are expressed throughout the central nervous system and GLP-1 may cross the blood-brain-barrier, an emerging hypothesis suggests that they may be promising therapeutic targets against brain dysfunctional insulin signaling-related pathologies. Importantly, GLP-1 actions depend not only on the direct effect mediated by its receptor activation, but also on the gut-brain axis involving an exchange of signals between both tissues via the vagal nerve, thereby regulating numerous physiological functions (e.g., energy homeostasis, glucose-dependent insulin secretion, as well as appetite and weight control). Amongst the incretin/GLP-1 mimetics class of anti-T2D drugs with an increasingly described neuroprotective potential, the already marketed liraglutide emerged as a GLP-1R agonist highly resistant to dipeptidyl peptidase-4 degradation (thereby having an increased half-life) and whose systemic GLP-1R activity is comparable to that of native GLP-1. Importantly, several preclinical studies showed anti-apoptotic, anti-inflammatory, anti-oxidant and neuroprotective effects of liraglutide against T2D, stroke and Alzheimer disease (AD), whereas several clinical trials, demonstrated some surprising benefits of liraglutide on weight loss, microglia inhibition, behavior and cognition, and in AD biomarkers. Herein, we discuss the GLP-1 action through the gut-brain axis, the hormone’s regulation of some autonomic functions and liraglutide’s neuroprotective potential.

Cardiometabolic Effects of a New Class of Antidiabetic Agents

PURPOSE

Within the past decade, many new classes of drugs have received approval from the US Food and Drug Administration for treatment of type 2 diabetes mellitus, including glucagon-like peptide-1agonists, dipeptidyl peptidase-4 inhibitors, and the sodium-glucose cotransporter-2 inhibitors. Many trials have been performed, and several more are currently ongoing to evaluate these drugs. This review addresses the broad therapeutic and pleiotropic effects of these drugs. The review also discusses the role of these drugs in the treatment paradigm for type 2 diabetes and identifies patients who would be suitable candidates for treatment with these drugs.

METHODS

In this comprehensive evidence-based review, the following databases were searched from 1990 to the present: PubMed/MEDLINE, Scopus, CINAHL, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Portal, and the American Diabetes Association and European Association for the Study of Diabetes abstract databases. Randomized clinical trials (RCTs) were only included for the main therapeutic and cardiovascular (CV) effects of these drug classes. For pleiotropic effects, RCTs were included unless no RCTs exist, in which case other studies as specified in the detailed Methods section were included.

FINDINGS

All 3 drug classes are effective in lowering hemoglobin A1c between 0.4% and 1.4%, depending on the drug class and population selected. These drug classes have beneficial effects on CV risk factors, such as weight, lipids, and blood pressure, in addition to lowering blood glucose levels. The CV tolerability of some drugs has been evaluated and found to be neutral; however, most trials are currently ongoing to assess CV tolerability. There are no concrete guidelines to determine where these drugs fit in the diabetes management paradigm, and there are ongoing trials to determine the best combination drug with metformin.

IMPLICATIONS

These 3 drug classes will potentially increase the armamentarium against hyperglycemia. However, the specific combinations with other antidiabetic drugs and populations that will best benefit from these drugs are still being tested. Future research is also being conducted on the use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors in patients with type 1 diabetes.

A multiplicity of targets: evaluating composite endpoint studies of the GLP-1 receptor agonists in type 2 diabetes

OBJECTIVE

Current type 2 diabetes (T2D) treatment guidelines include weight maintenance or loss, avoidance of hypoglycemia, and targets for blood pressure and circulating lipids, in addition to glycemic control. Increasingly, clinical trials and meta-analyses employ composite endpoints to capture the net clinical benefit of a given T2D intervention. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) represent a new class of injected antihyperglycemic agents that may be well suited to reaching many of these targets among patients failing on metformin monotherapy.

RESEARCH DESIGNS AND METHODS

Using MEDLINE, Embase and Google Scholar, studies were sought that employed composite endpoints and that reported outcomes with exenatide and/or liraglutide. Bibliographies of relevant review articles were consulted to search for additional reports.

RESULTS

Many trials have used the combination of HbA1c <7%, no weight gain and no hypoglycemic episodes as the composite endpoint in evaluating T2D therapies; however, at least 15 other distinct composite endpoints have been reported. Findings were relatively consistent across studies, regardless of how the composite endpoint was defined. Specifically, the GLP-1 RAs appear to be superior to other agents in their efficacy in providing T2D patients failing on metformin with a net clinical benefit, which can include avoidance of hyperglycemia and maintenance or improvement in body weight.

CONCLUSIONS

Use of composite endpoints represents an important advance in T2D. While no single such endpoint has achieved dominance in the field, widely used composite endpoints capture efficacy in glycemic control as well as safety and effects on markers of cardiovascular risk.

Glucagon-like peptide-1 receptor agonist therapeutics for total diabetes management: assessment of composite end-points

Assessment of the benefits of anti-diabetic drugs for type 2 diabetes requires analysis of composite end-points, taking HbA1c, bodyweight, hypoglycemia and other metabolic parameters into consideration; continuous, optimal glycemic control as well as bodyweight, blood pressure and lipid levels are critical to prevent micro- and macro-vascular complications. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are now established as an important total treatment strategy for type 2 diabetes, exerting glucose-lowering effects with little hypoglycemia risk and also ameliorating bodyweight, blood pressure and lipid levels, which are therapeutic targets for prevention of complications of the disease. The available data strongly suggest only beneficial effects of GLP-1RAs; however, long-term evaluation of the relevant composite end-points including health-related quality of life and cost-effectiveness remain to be investigated in adequately powered, prospective, controlled clinical trials. In the meantime, healthcare professionals need to be scrupulously attentive for potential, rare adverse events in patients using GLP-1RAs.

Potential side effects to GLP-1 agonists: understanding their safety and tolerability

INTRODUCTION

Glucagon-like peptide 1 receptor (GLP-1Rx) agonists might elicit unwelcome side effects and concerns have recently been raised about their safety.

AREAS COVERED

Available evidence about safety, tolerability and potential adverse events relative to GLP-1Rx agonists presently used. We searched the MEDLINE database using the terms: 'GLP-1 receptor agonists', 'Incretin therapy side effects', 'exenatide', ' liraglutide', 'exenatide long-acting release', 'lixisenatide'. Articles were selected on the basis of the study design and importance, in the light of authors' clinical experience and personal judgment. The main safety concern about GLP-1Rx agonists use is the possible association with increased risk of pancreatitis and/or tumors. This concern stems mainly from limited observations in animal models not confirmed in similar studies. Furthermore, clinical studies reporting association between GLP-1Rx agonist use and pancreatitis/cancer are marred by several biases and both clinical trials and post-marketing analyses failed to demonstrate a significant association.

EXPERT OPINION

As stated by both FDA and EMA, the safety concerns emerged so far about GLP-1RX agonists should not affect present prescribing habits. Thus, although a strict data monitoring must be encouraged, they should not prevent access to the benefits of an innovative treatment, such as GLP-1Rx agonists use, to a large diabetic population still confronted with unmet needs.

Extra-pancreatic effects of incretin-based therapies

Glucagon-like peptide-1 (GLP-1) stimulates insulin secretion and inhibits glucagon secretion in the pancreatic islets of Langerhans under hyperglycaemia. In type 2 diabetes (T2DM), GLP-1 improves glycaemic control without a hypoglycaemia risk. GLP-1 receptors have also been found in extra-pancreatic tissues, e.g., the cardiovascular system, the gastrointestinal system, and the central nervous system. Since cardiovascular comorbidities and degenerative neurological changes are associated with T2DM, the interest in the extrapancreatic effects of GLP-1 has increased. GLP-1-based therapies with either GLP-1 receptor agonists (GLP-1 RA) or DPP-4 inhibitors (that delay the degradation of endogenous GLP-1) have become widely used therapeutic options in T2DM. In clinical studies, GLP-1 RA have demonstrated a significant lowering of blood pressure that is independent of body weight changes. Preclinical data and small short-term studies with GLP-1 and GLP-1 RA have shown cardioprotective effects in ischaemia models. GLP-1 as well as a treatment with GLP-1 RA also induces a stable body weight loss by affecting GLP-1 signaling in the hypothalamus and by slowing gastric emptying. Regarding neuroprotective actions in degenerative neurological disease models for Parkinson's- or Alzheimer's disease or neurovascular complications like stroke, animal studies have shown positive results. In this article, a summary of the extrapancreatic effects of GLP-1 and GLP-1-based therapies is presented.

Differences in the HbA1c-lowering efficacy of glucagon-like peptide-1 analogues between Asians and non-Asians: a systematic review and meta-analysis

AIMS

To compare the HbA1c-lowering efficacy of glucagon-like peptide-1 (GLP-1) analogues between Asians and non-Asians with type 2 diabetes.

METHODS

We searched randomized controlled trials from MEDLINE, EMBASE, LILACS, CENTRAL and ClinicalTrials.gov. Studies described in English were included if the treatment duration was 12 weeks or more, information about ethnicity and baseline HbA1c values were available and a GLP-1 analogue was compared with a placebo. For the ethnic comparison, we divided the studies into Asian-dominant studies (≥ 50% Asian participants) and non-Asian-dominant studies (<50% Asian participants).

RESULTS

Among the 837 searched studies, 15 trials were included for the meta-analysis. The weighted mean difference of HbA1c with GLP-1 analogues was -1.16% [95% confidence interval (CI) -1.48, -0.85] in the Asian-dominant studies and -0.83% (95% CI -0.97, -0.70) in the non-Asian-dominant studies. The between-group difference was -0.32% (95% CI -0.64, -0.01; p = 0.04). The relative risk (RR) with 95% CIs for achieving the target HbA1c ≤ 7.0% tended to be greater in the Asian-dominant studies [RR 5.7 (3.8, 8.7)] than in the non-Asian-dominant studies [RR 2.8 (2.4, 3.3)]. Body weight changes were similar between the two groups. Hypoglycaemia tended to be more common in Asian-dominant studies (RR 2.8 [2.3, 3.5]) than in non-Asian-dominant studies (RR 1.5 [1.2, 1.8]), but severe hypoglycaemia was very rare in both groups.

CONCLUSION

GLP-1 analogues lower HbA1c more in Asian-dominant studies than in non-Asian-dominant studies. Further studies are warranted to explore the potential mechanisms of the ethnic difference.

The extra-pancreatic effects of GLP-1 receptor agonists: a focus on the cardiovascular, gastrointestinal and central nervous systems

The glucagon-like peptide-1 receptor agonists (GLP-1RAs) exenatide, liraglutide and lixisenatide have been shown to improve glycaemic control and beta-cell function with a low risk of hypoglycaemia in people with type 2 diabetes. GLP-1 receptors are also expressed in extra-pancreatic tissues and trial data suggest that GLP-1RAs also have effects beyond their glycaemic actions. Preclinical studies using native GLP-1 or GLP-1RAs provide substantial evidence for cardioprotective effects, while clinical trial data have shown beneficial actions on hypertension and dyslipidaemia in people with type 2 diabetes. Significant weight loss has been reported with GLP-1RAs in both people with type 2 diabetes and obese people without diabetes. GLP-1RAs also slow down gastric emptying, but preclinical data suggest that the main mechanism behind GLP-1RA-induced weight loss is more likely to involve their effects on appetite signalling in the brain. GLP-1RAs have also been shown to exert a neuroprotective role in rodent models of stroke, Alzheimer's disease and Parkinson's disease. These extra-pancreatic effects of GLP-1RAs could provide multi-factorial benefits to people with type 2 diabetes. Potential adverse effects of GLP-1RA treatment are usually manageable but may include gastrointestinal effects, increased heart rate and renal injury. While extensive further research is still required, early data suggest that GLP-1RAs may also have the potential to favourably impact cardiovascular disease, obesity or neurological disorders in people without diabetes in the future.

Composite endpoints in trials of type-2 diabetes

Composite endpoints (CEPs) are being used more frequently as outcomes for trials of drugs in type-2 diabetes. We reviewed the literature to determine how CEPs have been used to date in trials of drugs for type-2 diabetes. A systematic search was undertaken on Medline, Embase and Cochrane databases and Clinicaltrials.gov for randomized controlled trials of currently marketed agents including SGLT-2 inhibitors (dapagliflozin), GLP-1 agonists (exenatide, liraglutide) and DPP-4 inhibitors (linagliptin, saxagliptin, sitagliptin and vildagliptin). CEPs used were identified as well as numbers and percentages of patients achieving each. Thirty-six studies were identified that reported results on ≥1 CEP; 15 different CEPs were reported (7 with 2 components, 8 with 3 components). All CEPs addressed goals recommended by the American Diabetes Association (ADA). All included HbA1c<7%; other endpoints measured weight, blood pressure and hypoglycaemic events. Results were obtained for CEPs from 6 months to 2 years. Rates of achieving CEPs decreased with increasing numbers of components and outcomes assessed. CEPs are becoming used as indicators of clinical outcomes in type-2 diabetes trials, but are still not common. More research is required to identify optimal CEPs. Standardization of outcomes and their reporting is needed.

APOE*3Leiden.CETP transgenic mice as model for pharmaceutical treatment of the metabolic syndrome

AIMS

This study aimed to investigate systematically (i) the appropriate dietary conditions to induce the features of the MetS in APOE*3Leiden.humanCholesteryl Ester Transfer Protein (E3L.CETP) mice and (ii) whether the response of this model to different antidiabetic and hypolipidemic drugs is similar as in humans.

METHODS

Male obese, IR and dyslipidemic E3L.CETP mice were treated with antidiabetic drugs rosiglitazone, liraglutide or an experimental 11β-hydroxysteroid-dehydrogenase-1 (HSD-1) inhibitor, or with hypolipidemic drugs atorvastatin, fenofibrate or niacin for 4-6 weeks. The effects on bw, IR and plasma and liver lipids were assessed.

RESULTS

Rosiglitazone, liraglutide and HSD-1 inhibitor significantly decreased glucose and insulin levels or IR. Liraglutide and HSD-1 inhibitor also decreased bw. Atorvastatin, fenofibrate and niacin improved the dyslipidemia and fenofibrate and niacin increased high-density lipoprotein (HDL) cholesterol. In addition, hepatic triglycerides were significantly decreased by treatment with rosiglitazone and liraglutide, while hepatic cholesterol esters were significantly decreased by rosiglitazone and atorvastatin.

CONCLUSIONS

We conclude that the E3L.CETP mouse is a promising novel translational model to investigate the effects of new drugs, alone or in combination, that affect IR, diabetic dyslipidemia and non-alcoholic fatty liver disease (NAFLD).

Management of unmet needs in type 2 diabetes mellitus: the role of incretin agents

The leading cause of morbidity and mortality in type 2 diabetes mellitus is cardiovascular disease. There is a need for type 2 diabetes therapies that act in concert with available agents to provide adequate glycemic control without causing hypoglycemia and weight gain, which are associated with increases in cardiovascular risk. Incretin-based agents-dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists-are the newest class of antihyperglycemic therapies. Liraglutide and exenatide, glucagon-like peptide-1 receptor agonists recently approved in Canada, have been shown to effectively lower blood glucose levels while also having beneficial effects on body weight and systolic blood pressure. The objective of this article is to review and discuss incretin-based agents, with a focus on their effects on blood glucose control, body weight and cardiovascular risk factors in patients with type 2 diabetes. Relevant data were obtained by literature search using the EMBASE, MEDLINE and PubMed databases.

GLP-1R responsiveness predicts individual gastric bypass efficacy on glucose tolerance in rats

Several bariatric operations are currently used to treat obesity and obesity-related comorbidities. These vary in efficacy, but most are more effective than current pharmaceutical treatments. Roux-en-Y gastric bypass (RYGB) produces substantial body weight (BW) loss and enhanced glucose tolerance, and is associated with increased secretion of the gut hormone glucagon-like peptide 1 (GLP-1). Given the success of GLP-1-based agents in lowering blood glucose levels and BW, we hypothesized that an individual sensitivity to GLP-1 receptor agonism could predict metabolic benefits of surgeries associated with increased GLP-1 secretion. One hundred ninety-seven high-fat diet-induced obese male Long-Evans rats were monitored for BW loss during exendin-4 (Ex4) administration. Stable populations of responders and nonresponders were identified based on Ex4-induced BW loss and GLP-1-induced improvements in glucose tolerance. Subpopulations of Ex4 extreme responders and nonresponders underwent RYGB surgery. After RYGB, responders and nonresponders showed similar BW loss compared with sham, but nonresponders retained impaired glucose tolerance. These data indicate that the GLP-1 response tests may predict some but not all of the improvements observed after RYGB. These findings present an opportunity to optimize the use of bariatric surgery based on an improved understanding of GLP-1 biology and suggest an opportunity for a more personalized therapeutic approach to the metabolic syndrome.

Tolerability of nausea and vomiting and associations with weight loss in a randomized trial of liraglutide in obese, non-diabetic adults

BACKGROUND

Liraglutide 3.0 mg, with diet and exercise, produced substantial weight loss over 1 year that was sustained over 2 years in obese non-diabetic adults. Nausea was the most frequent side effect.

OBJECTIVE

To evaluate routinely collected data on nausea and vomiting among individuals on liraglutide and their influence on tolerability and body weight.

DESIGN

A randomized, placebo-controlled, double-blind 20-week study with an 84-week extension (sponsor unblinded at 20 weeks, open-label after 1 year) in eight European countries (Clinicaltrials.gov: NCT00422058).

SUBJECTS

After commencing a 500-kcal/day deficit diet plus exercise, 564 participants (18-65 years, body mass index (BMI) 30-40 kg m(-2)) were randomly assigned (after a 2-week run-in period) to once-daily subcutaneous liraglutide (1.2, 1.8, 2.4 or 3.0 mg), placebo or open-label orlistat (120 mg × 3 per day). After 1 year, participants on liraglutide/placebo switched to liraglutide 2.4 mg, and subsequently, to liraglutide 3.0 mg (based on 20-week and 1-year results, respectively).

RESULTS

The intention-to-treat population comprised 561 participants (n=90-98 per arm, age 45.9±10.3 years, BMI 34.8±2.7 kg m(-2) (mean±s.d.)). In year 1, more participants reported ⩾1 episode of nausea/vomiting on treatment with liraglutide 1.2-3.0 mg (17-38%) than with placebo or orlistat (both 4%, P⩽0.001). Most episodes occurred during dose escalation (weeks 1-6), with 'mild' or 'moderate' symptoms. Among participants on liraglutide 3.0 mg, 48% reported some nausea and 13% some vomiting, with considerable variation between countries, but only 4 out of 93 (4%) reported withdrawals. The mean 1-year weight loss on treatment with liraglutide 3.0 mg from randomization was 9.2 kg for participants reporting nausea/vomiting episodes, versus 6.3 kg for those with none (a treatment difference of 2.9 kg (95% confidence interval 0.5-5.3); P=0.02). Both weight losses were significantly greater than the respective weight losses for participants on placebo (P<0.001) or orlistat (P<0.05). Quality-of-life scores at 20 weeks improved similarly with or without nausea/vomiting on treatment with liraglutide 3.0 mg.

CONCLUSION

Transient nausea and vomiting on treatment with liraglutide 3.0 mg was associated with greater weight loss, although symptoms appeared tolerable and did not attenuate quality-of-life improvements. Improved data collection methods on nausea are warranted.

A retrospective, case-note survey of type 2 diabetes patients prescribed incretin-based therapies in clinical practice

INTRODUCTION

While incretin-based therapies have been compared in clinical trials, data comparing their relative efficacy in clinical practice remain limited, particularly when prescribed according to clinical guidelines. This study assessed the clinical and cost-effectiveness of, and patient preference for, incretin-based therapies initiated according to the National Institute for Health and Clinical Excellence (NICE) recommendations in UK clinical practice.

METHODS

In a retrospective chart audit, anonymized data were collected for patients receiving incretin-based therapy according to NICE recommendations in clinical practice in Wales, UK. Parameters assessed included glycated hemoglobin (HbA1c), weight, achievement of NICE treatment continuation criteria, adverse events, treatment discontinuation, and drug cost-effectiveness based on observed treatment effects. Treatment preference for a dipeptidyl peptidase-4 inhibitor (DPP-4i) or glucagon-like peptide-1 receptor agonist (GLP-1RA) was assessed prospectively.

RESULTS

Patients (1,114) were followed-up for a median of 48 weeks (256 received liraglutide, 148 received exenatide twice daily, and 710 received a DPP-4i). Liraglutide reduced HbA1c significantly more versus exenatide or DPP-4i (both P < 0.05). Weight changes were similar for GLP-1RAs but significantly greater vs. DPP-4is (both P < 0.05). NICE treatment continuation criteria were met by 32% and 24% of liraglutide 1.2 mg- and exenatide-treated patients (≥1% HbA1c reduction, ≥3% weight loss), and 61% of DPP-4i-treated patients (≥0.5% HbA1c reduction). Life-years gained per patient were 0.12, 0.08, and 0.07, and costs per quality-adjusted life-year were £16,505, £16,648, and £20,661 for liraglutide, exenatide, and DPP-4is, respectively. More patients (62.5%) preferred the GLP-1RA profile, with these patients having higher baseline body mass index score and HbA1c values, and longer diabetes duration than those preferring the DPP-4i profile.

CONCLUSION

When prescribed according to NICE recommendations, incretin-based therapies are both clinically and cost-effective options, with liraglutide providing greatest HbA1c reductions. Greater body weight reductions occur with GLP-1RAs compared with DPP-4is. Patients with higher baseline HbA1c and longer diabetes duration prefer a GLP-1RA profile versus a DPP-4i.

Glucagon-like peptide-1 analogues: An overview

Abnormalities of the incretin axis have been implicated in the pathogenesis of type 2 diabetes mellitus. Glucagon-like peptide-1 (GLP-1) and gastroinhibitory intestinal peptide constitutes >90% of all the incretin function. Augmentation of GLP-1 results in improvement of beta cell health in a glucose-dependant manner (post-prandial hyperglycemia) and suppression of glucagon (fasting hyperglycemia), amongst other beneficial pleiotropic effects. Native GLP-1 has a very short plasma half-life and novel methods have been developed to augment its half life, such that its anti-hyperglycemic effects can be exploited. They can be broadly classified as exendin-based therapies (exenatide, exenatide once weekly), DPP-4-resistant analogues (lixisenatide, albiglutide), and analogues of human GLP-1 (liraglutide, taspoglutide). Currently, commercially available analogues are exenatide, exenatide once weekly, and liraglutide. This review aims to provide an overview of most GLP-1 analogues.

Targeted estrogen delivery reverses the metabolic syndrome

We report the development of a new combinatorial approach that allows for peptide-mediated selective tissue targeting of nuclear hormone pharmacology while eliminating adverse effects in other tissues. Specifically, we report the development of a glucagon-like peptide-1 (GLP-1)-estrogen conjugate that has superior sex-independent efficacy over either of the individual hormones alone to correct obesity, hyperglycemia and dyslipidemia in mice. The therapeutic benefits are driven by pleiotropic dual hormone action to improve energy, glucose and lipid metabolism, as shown by loss-of-function models and genetic action profiling. Notably, the peptide-based targeting strategy also prevents hallmark side effects of estrogen in male and female mice, such as reproductive endocrine toxicity and oncogenicity. Collectively, selective activation of estrogen receptors in GLP-1-targeted tissues produces unprecedented efficacy to enhance the metabolic benefits of GLP-1 agonism. This example of targeting the metabolic syndrome represents the discovery of a new class of therapeutics that enables synergistic co-agonism through peptide-based selective delivery of small molecules. Although our observations with the GLP-1-estrogen conjugate justify translational studies for diabetes and obesity, the multitude of other possible combinations of peptides and small molecules may offer equal promise for other diseases.

Effects of liraglutide on β-cell-specific glucokinase-deficient neonatal mice

The glucagon-like peptide-1 receptor agonist liraglutide is used to treat diabetes. A hallmark of liraglutide is the glucose-dependent facilitation of insulin secretion from pancreatic β-cells. In β-cells, the glycolytic enzyme glucokinase plays a pivotal role as a glucose sensor. However, the role of glucokinase in the glucose-dependent action of liraglutide remains unknown. We first examined the effects of liraglutide on glucokinase haploinsufficient (Gck(+/-)) mice. Single administration of liraglutide significantly improved glucose tolerance in Gck(+/-) mice without increase of insulin secretion. We also assessed the effects of liraglutide on the survival rates, metabolic parameters, and histology of liver or pancreas of β-cell-specific glucokinase-deficient (Gck(-/-)) newborn mice. Liraglutide reduced the blood glucose levels in Gck(-/-) neonates but failed to prolong survival, and all the mice died within 1 wk. Furthermore, liraglutide did not improve glucose-induced insulin secretion in isolated islets from Gck(-/-) neonates. Liraglutide initially prevented increases in alanine aminotransferase, free fatty acids, and triglycerides in Gck(-/-) neonates but not at 4 d after birth. Liraglutide transiently prevented liver steatosis, with reduced triglyceride contents and elevated glycogen contents in Gck(-/-) neonate livers at 2 d after birth. Liraglutide also protected against reductions in β-cells in Gck(-/-) neonates at 4 d after birth. Taken together, β-cell glucokinase appears to be essential for liraglutide-mediated insulin secretion, but liraglutide may improve glycemic control, steatosis, and β-cell death in a glucokinase-independent fashion.

Diabetes-related alterations in the enteric nervous system and its microenvironment

Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of myenteric neurons are especially susceptible to the development of diabetic neuropathy. Additionally, different susceptibility of nitrergic neurons located in different intestinal segments to diabetic damage and their different levels of responsiveness to insulin treatment have been revealed. These findings indicate the importance of the neuronal microenvironment in the pathogenesis of diabetic nitrergic neuropathy. The main focus of this review therefore was to summarize recent advances related to the diabetes-related selective nitrergic neuropathy and associated motility disturbances. Special attention was given to the findings on capillary endothelium and enteric glial cells. Growing evidence indicates that capillary endothelium adjacent to the myenteric ganglia and enteric glial cells surrounding them are determinative in establishing the ganglionic microenvironment. Additionally, recent advances in the development of new strategies to improve glycemic control in type 1 and type 2 diabetes mellitus are also considered in this review. Finally, looking to the future, the recent and promising results of metagenomics for the characterization of the gut microbiome in health and disease such as diabetes are highlighted.

Evaluation of vildagliptin and fixed dose combination of vildagliptin and metformin on glycemic control and insulin dose over 3 months in patients with type 2 diabetes mellitus

OBJECTIVE

Addition of vildagliptin to ongoing insulin therapy may help in terms of overall glycemic control as well as reduction in dose of insulin and weight. This study sought to evaluate the effect of vildagliptin and fixed dose combination (FDC) of vildagliptin and metformin in patients in ongoing insulin therapy for Type 2 diabetes mellitus.

MATERIALS AND METHODS

This was an open label, prospective, non-randomised, multicentric observational study. In this study 400 patients with T2DM on insulin were enrolled and allocated with the treatment of vildagliptin 50 mg in monotherapy and FDC of vildagliptin 50 mg and metformin strengths as 500/ 850 / 1000 mg. Baseline investigations included fasting blood glucose (FBG) and post prandial plasma glucose (PPPG) Estimation and glycosylated haemoglobin (HbA1c).

RESULTS

The combined analysis was carried out on 300 completed patients in this study, who were treated with vildagliptin or FDC of vildagliptin and metformin. The difference in mean value of insulin dose (MID) showed a highly significant decrease (P <0.0001) from baseline to end of the treatment i.e. from 36.26 ± 18.21 to 26.87 ± 16.49 IU. A highly significant decrease (P <0.0001) in FBG from 194.94 ± 56.19 to 124.93 ± 30.11 mg/dl was observed. Similarly PPPG showed a highly significant (P <0.0001) decrease from baseline to end of the treatment i.e. from 287.60 mg/dl to 172.05 mg/dl and there was highly significant (P <0.0001) decrease in HbA1c i.e. from 9.01% to 7.65% respectively. At the same time, highly significant decrease (P <0.0001) in mean weight also observed from baseline to end of the treatment i.e. from 71.23 ± 11.06 kg to 70.06 ± 10.62 Kg.

CONCLUSION

Addition of vildagliptin and FDC of vildagliptin and metformin is an effective strategy in glycemic control, reduction in dose of insulin and weight of patients suffering with T2DM.

Generating orally active galanin analogues with analgesic activities

The endogenous neuropeptide galanin has anticonvulsant and analgesic properties mediated by galanin receptors expressed in the central and peripheral nervous systems. Our previous work showed that by combining truncation of the galanin peptide with N- and C-terminal modifications afforded analogues that suppress seizures or pain upon intraperitoneal (i.p.) administration. To generate orally active galanin analogues, the previously reported lead compound Gal-B2 (NAX 5055) was redesigned by 1) central truncation, (2) introduction of D-amino acids, and 3) addition of backbone spacers. Analogue D-Gal(7-Ahp)-B2, containing 7-aminoheptanoic acid as a backbone spacer and an oligo-D-lysine motif at the C terminus, exhibits anticonvulsant and analgesic activity post-i.p. administration. Oral administration of D-Gal(7-Ahp)-B2 demonstrates analgesic activity with decreases in both acute and inflammatory pain in the mouse formalin model of pain at doses as low as 8 mg kg(-1) .