Insulin plus incretin agent combination therapy in type 2 diabetes: a systematic review

Metabolic and cardiovascular benefits and risks of 4-hydroxy guanabenz hydrochloride: α2-adrenoceptor and trace amine-associated receptor 1 ligand

BACKGROUND

α2-adrenoceptor ligands have been investigated as potential therapeutic agents for the treatment of obesity. Our previous studies have shown that guanabenz reduces the body weight of obese rats, presumably through its anorectic action. This demonstrates an additional beneficial effect on selected metabolic parameters, including glucose levels. The purpose of this present research was to determine the activity of guanabenz's metabolite-4-hydroxy guanabenz hydrochloride (4-OH-Guanabenz).

METHODS

We performed in silico analyses, involving molecular docking to targets of specific interest as well as other potential biological targets. In vitro investigations were conducted to assess the selectivity profile of 4-OH-Guanabenz binding to α-adrenoceptors, along with intrinsic activity studies involving α2-adrenoceptors and trace amine-associated receptor 1 (TAAR1). Additionally, the effects of 4-OH-Guanabenz on the body weight of rats and selected metabolic parameters were evaluated using the diet-induced obesity model. Basic safety and pharmacokinetic parameters were also examined.

RESULTS

4-OH-guanabenz is a partial agonist of α2A-adrenoceptor. The calculated EC50 value for it is 316.3 nM. It shows weak agonistic activity at TAAR1 too. The EC50 value for 4-OH-Guanabenz calculated after computer simulation is 330.6 µM. Its primary mode of action is peripheral. The penetration of 4-OH-Guanabenz into the brain is fast (tmax = 15 min), however, with a low maximum concentration of 64.5 ng/g. 4-OH-Guanabenz administered ip at a dose of 5 mg/kg b.w. to rats fed a high-fat diet causes a significant decrease in body weight (approximately 14.8% compared to the baseline weight before treatment), reduces the number of calories consumed by rats, and decreases plasma glucose and triglyceride levels.

CONCLUSIONS

The precise sequence of molecular events within the organism, linking the impact of 4-OH-Guanabenz on α2A-adrenoceptor and TAAR1 with weight reduction and the amelioration of metabolic disturbances, remains an unresolved matter necessitating further investigation. Undoubtedly, the fact that 4-OH-Guanabenz is a metabolite of a well-known drug has considerable importance, which is beneficial from an economic point of view and towards its further development as a drug candidate.

Instituting a Successful Discharge Plan for Patients With Type 2 Diabetes: Challenges and Solutions

Achieving target inpatient glycemic management outcomes has been shown to influence important clinical outcomes such as hospital length of stay and readmission rates. However, arguably the most profound, lasting impact of inpatient diabetes management is achieved at the time of discharge-namely reconciling and prescribing the right medications and making referrals for follow-up. Discharge planning offers a unique opportunity to break through therapeutic inertia, offer diabetes self-management education, and institute an individualized treatment plan that prepares the patient for discharge and promotes self-care and engagement. However, the path to a successful discharge plan can be fraught with potential pitfalls for clinicians, including lack of knowledge and experience with newer diabetes medications, costs, concerns over insurance coverage, and lack of time and resources. This article presents an algorithm to assist clinicians in selecting discharge regimens that maximize benefits and reduce barriers to self-care for patients and a framework for creating an interdisciplinary hospital diabetes discharge program.

Lessons From a Diabetes Clinic: Achieving Glycemic Goals and Clinical Use of Antidiabetic Agents in Patients With Type 2 Diabetes

The proportion of patients with type 2 diabetes who achieve their glycemic goals remains low. We examined medical records and A1C results from patient visits to our referral diabetes center between 21 March to 20 July 2018. After stratifying patients into four groups-monotherapy, dual therapy, triple therapy, or insulin therapy-we found that the target A1C of ≤7.0% was achieved by 86% of patients and that A1C was uniformly low across the treatment categories. Our individualized approach, which included high use of glucagon-like peptide-1 receptor agonists and low use of sulfonylureas, may have contributed to these results.

Intensification of Basal Insulin Therapy with Lixisenatide in Patients with Type 2 Diabetes in a Real-World Setting: The BASAL-LIXI Study

•

Adding lixisenatide to basal insulin was effective for uncontrolled type 2 diabetes.

•

Glycemic control improved and body weight lowered during 24 weeks of treatment.

•

These benefits were achieved with a low risk of hypoglycemia in clinical practice.

•

These findings in the clinical practice setting support those of clinical trials.

Background

Basal insulin reduces fasting blood glucose levels, but postprandial blood glucose levels may remain higher. Traditional strategies with rapid insulin intensification can cause hypoglycemic episodes and weight gain. Glucagon-like peptide-1 receptor agonists, such as the short-acting lixisenatide, are able to control postprandial excursions, without weight gain, and with a low risk of hypoglycemic events.

Objective

Due to the limited data on the combination of lixisenatide with basal insulin (with or without oral antidiabetes drugs) in clinical practice, this study evaluated changes in parameters associated with glycemic control and anthropometric data after 24 weeks of this therapy intensification.

Methods

This was a multicenter, retrospective observational study of 129 patients with type 2 diabetes that was uncontrolled by basal insulin. Their treatment was intensified by the addition of lixisenatide at least 24 weeks before being included in the study. Data were retrospectively collected to determine changes in glycated hemoglobin (HbA1c) levels, blood glucose levels, weight, and body mass index. Adverse reactions and hypoglycemic events were also recorded.

Results

After 24 weeks of therapy intensification with lixisenatide, a significant reduction in HbA1c levels was observed (–1.1%; P < 0.001). An HbA1c <7% was achieved in 30.2% of patients, and 17.1% reached an HbA1c <6.5%. There was a reduction in fasting blood glucose (31.8 [60.3] mg/dL; P < 0.001) and postprandial blood glucose (55.0 [49] mg/dL; P < 0.001) levels, as well as body weight (4.0 [5.4] kg; P < 0.001) and body mass index (1.5 [1.9]; P < 0.001). The most commonly observed adverse reactions were nausea (n = 9), in line with previous studies. Hypoglycemia events were rare; only reported in 2 patients.

Conclusions

Intensification strategy based on lixisenatide added to basal insulin (with or without oral antidiabetes drugs) can be an effective treatment option in patients with uncontrolled type 2 diabetes. In this small, selected population, glycemic control was significantly improved in terms of HbA1, fasting blood glucose levels, and postprandial glucose levels, with a reduction of body weight and low risk of hypoglycemic events. (Curr Ther Res Clin Exp. 2018; 79:XXX–XXX)

Adding prandial GLP-1 receptor agonists to basal insulin: a promising option for type 2 diabetes therapy

BACKGROUND

Diabetes mellitus is a serious and increasingly prevalent condition in Canada and around the world. Treatment strategies have become increasingly complex, with a widening array of pharmacological agents available for glycemic management in type 2 diabetes mellitus (T2DM). New therapies that act in concert with available basal insulins may represent alternatives to basal insulin intensification with prandial or pre-mixed insulin. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have recently shown promise as useful additions to basal insulin, with significant reductions in glycated hemoglobin and potentially beneficial effects on body weight. This review will focus on pivotal clinical trials to assess the potential benefits of adding prandial GLP-1 RAs to basal insulin in patients with T2DM.

METHODS

Clinical studies combining prandial GLP-1 RAs and basal insulin (published between 2011 and July 2017) were identified and reviewed in PubMed, the Cochrane Central Register of Clinical Trials (Issue 6, June 2017), and clinicaltrials.gov.

RESULTS

Most of the studies presented in this review show that the addition of a prandial GLP-1 RA to basal insulin results in equal or slightly superior efficacy compared to the addition of prandial insulin, together with weight loss and less hypoglycemia.

CONCLUSIONS

The results of the studies suggest that a prandial GLP-1 RA as an add-on to basal insulin may be a safe and effective treatment intensification option (vs basal-plus or basal-bolus insulin).

A Review of the Long-Term Efficacy, Tolerability, and Safety of Exenatide Once Weekly for Type 2 Diabetes

INTRODUCTION

Exenatide once weekly (ExeOW, Bydureon®, Astra Zeneca), a drug belonging to the class of glucagon-like peptide-1 (GLP-1) receptor agonists, is the first agent approved for treatment of type 2 diabetes (T2D) that can be administered on a weekly basis.

METHODS

Data concerning treatment of T2D with ExeOW are reviewed with special reference to its long-term efficacy, tolerability, and safety. Relevant literature was identified through the PubMed database from inception to January 2015.

RESULTS

In randomized clinical trials ExeOW, as add-on to oral antidiabetics, achieved significantly improved glycemic control compared to maximum recommended doses of exenatide twice daily, sitagliptin, pioglitazone, and insulin glargine, as measured by HbA1c. In drug-naïve patients ExeOW was superior to sitagliptin and non-inferior to metformin, whereas non-inferiority to pioglitazone and liraglutide was not proven. In different trials reductions in HbA1c ranged from -1.1% to -2.0%. ExeOW therapy over 6 months was also associated with a mean weight loss of -2 to -4 kg, improved systolic blood pressure and lipid profile, and no hypoglycemia unless associated to sulfonylurea. ExeOW long-term therapy up to 3-6 years allowed persistent glycemic control (HbA1c -1.6%), sustained decreases in blood pressure (-2 mmHg), and improvements of lipid profile. ExeOW tolerability was comparable to that of the other GLP-1 receptor agonists, with better gastrointestinal tolerability when direct comparison was done (namely liraglutide and exenatide BID), but higher incidence of injection site reactions and few treatment discontinuations mainly due to gastrointestinal events.

CONCLUSION

ExeOW is a well-tolerated and convenient option for long-term treatment of T2D allowing significant and persistent glycemic control with moderate weight loss and low risk of hypoglycemia unless associated with sulfonylureas.

Efficacy and safety of coadministration of sitagliptin with insulin glargine in type 2 diabetes

BACKGROUND

The aim of the randomized present study was to compare the therapeutic efficacy and safety of a combination of sitagliptin, a dipeptidyl peptidase (DPP)-4 inhibitor, plus insulin glargine (GL + sita) with that of premixed insulin aspart 30 (NOV) for type 2 diabetes (T2D) patients controlled with oral hypoglycemic drugs (HbA1c 7 %-9 %).

METHODS

Sixty-five patients were randomized (1:  1) to the GL + sita (n = 33) and NOV (n = 32) groups and were treated with the combination regimen or premixed insulin twice a day for 16 weeks. The primary endpoint was mean change in HbA1c. Secondary endpoints included fasting blood glucose, blood glucose profiles (seven time points), rate of achieving target HbA1c (<7 % or ≤6.5 %), insulin dose, incidence of hypoglycemia, and body weight.

RESULTS

After 16 weeks, there was no significant difference in HbA1c between the two groups, although more patients achieved HbA1c <7.0 % in the GL + sita group. There was a significant difference in body weight changes between the GL + sita and NOV groups (-0.45 vs 1.52 kg, respectively; P < 0.001). Mean plasma glucose and the mean amplitude of glycemic excursion were significantly lower in the GL + sita than NOV group (P < 0.005), as was the incidence of symptomatic hypoglycemia (2.85 % vs. 13.3 %, respectively; P < 0.001).

CONCLUSION

The combination of GL + sita greatly improved HbA1c in T2D patients (HbA1c 7 %-9 %) with an efficacy that was equal to that of premixed insulin. Thus, GL + sita treatment is a viable option for patients who fail to achieve glycemic control using oral hypoglycemic drugs.

Insulin Degludec/Liraglutide: A Review in Type 2 Diabetes

Insulin degludec/liraglutide (Xultophy(®)), a fixed-ratio combination of an ultra-long-acting insulin analogue and a glucagon-like protein-1 (GLP-1) receptor agonist, is available in the EU for the management of inadequately controlled type 2 diabetes. Once-daily subcutaneous insulin degludec/liraglutide as add-on therapy to oral antidiabetics was effective and generally well tolerated in adults with inadequately controlled type 2 diabetes in several well designed 26-week phase III trials. In insulin-naive patients, add-on insulin degludec/liraglutide provided significantly greater improvements in glycated haemoglobin (HbA1c) levels than add-on insulin degludec, liraglutide or placebo, or unchanged GLP-1 receptor agonists (i.e. liraglutide or exenatide). In the extension of one of these trials, the efficacy of add-on insulin degludec/liraglutide was maintained for a total of 52 weeks. In insulin-experienced patients, add-on insulin degludec/liraglutide was significantly more effective with regard to improvements in HbA1c levels than add-on insulin degludec (at equivalent doses) or ongoing insulin glargine therapy. Add-on insulin degludec/liraglutide was associated with a lower incidence of confirmed hypoglycaemia than add-on insulin degludec in insulin-naive patients or ongoing insulin glargine in insulin-experienced patients, and a lower initial rate of nausea than add-on liraglutide. Thus, once-daily subcutaneous insulin degludec/liraglutide is a useful add-on therapy option for adult patients with inadequately controlled type 2 diabetes.

The effects of GLP-1 analogues in obese, insulin-using type 2 diabetes in relation to eating behaviour

Background Glucagon-like peptide-1 receptor agonists (GLP-1 RA) added to insulin in type 2 diabetes patients have shown to lower body weight, improve glycaemic control and reduce total daily insulin dose in short term studies, although the individual response greatly varies. Objective To evaluate GLP-1 RA treatment on body weight, glycaemic control and total daily insulin dose in obese, insulin-using type 2 diabetes patients after 2 years follow-up in a real life setting and to explore a possible relation with eating behaviour. Setting The Martini Hospital and the University Medical Center in Groningen in the Netherlands. Methods Eligible patients were at least 18 years of age, were on insulin therapy and obese (BMI > 30 kg/m²), started GLP-1 RA treatment. At baseline eating behaviour was classified according to the validated Dutch Eating Behaviour Questionnaire. A 2 years follow-up was performed. Main outcome measures Body weight, HbA1c and total daily insulin dose. Results 151 Patients started with exenatide or liraglutide. 120 patients completed the 2 years follow-up. From baseline to 2 years, body weight (mean ± SD) changed from 117.9 ± 22.1 to 107.9 ± 22.9 kg (P < 0.0001), HbA1c (median, IQR) changed from 7.9 (7.2–8.9) to 7.6 (6.9–8.3) % [63 (55–74) to 60 (52–67) mmol/mol] (P < 0.0001), total daily insulin dose changed from 90 (56–150) to 60 (0–100) Units/day (P < 0.0001). Weight change differed between eating behaviour groups (P < 0.001) in which external eating behaviour (n = 17) resulted in the smallest decline (−3.1 %) and restrained (n = 41) in the greatest (−10.3 %) in comparison with emotional (n = 37, −8.5 %) and indifferent (n = 25, −9.6 %) eating behaviours. Conclusion Two year of GLP-1 RA treatment resulted in a sustained reduction of weight, HbA1c and total daily insulin dose in obese, insulin-using type 2 diabetes patients in a real life setting. Largest weight loss was achieved in patients with a predominant restraint eating pattern while a predominant external eating pattern resulted in the smallest weight reduction.

IDegLira Improves Both Fasting and Postprandial Glucose Control as Demonstrated Using Continuous Glucose Monitoring and a Standardized Meal Test

OBJECTIVE

IDegLira is a novel, fixed-ratio combination of the long-acting basal insulin, insulin degludec, and the long-acting glucagon-like peptide-1 analog liraglutide. We studied the effect of IDegLira versus its components on postprandial glucose (PPG) in type 2 diabetes.

METHODS

In this substudy, 260 (15.6%) of the original 1663 patients with inadequate glycemic control participating in a 26-week, open-label trial (DUAL I) were randomized 2:1:1 to once-daily IDegLira, insulin degludec or liraglutide. Continuous glucose monitoring (CGM) for 72 hours and a meal test were performed.

RESULTS

At week 26, IDegLira produced a significantly greater decrease from baseline in mean PPG increment (normalized iAUC0-4h) than insulin degludec (estimated treatment difference [ETD] -12.79 mg/dl [95% CI: -21.08; -4.68], P = .0023) and a similar magnitude of decrease as liraglutide (ETD -1.62 mg/dl [95% CI: -10.09; 6.67], P = .70). CGM indicated a greater reduction in change from baseline in PPG increment (iAUC0-4h) for IDegLira versus insulin degludec over all 3 main meals (ETD -6.13 mg/dl [95% CI: -10.27, -1.98], P = .0047) and similar reductions versus liraglutide (ETD -1.80 mg/dl [95% CI: -2.52, 5.95], P = .4122). Insulin secretion ratio and static index were greater for IDegLira versus insulin degludec (P = .048 and P = .006, respectively) and similar to liraglutide (P = .45 and P = .895, respectively).

CONCLUSIONS

Once-daily IDegLira provides significantly better PPG control following a mixed meal test than insulin degludec. The improvement is at least partially explained by higher endogenous insulin secretion and improved beta cell function with IDegLira. The benefits of liraglutide on PPG control are maintained across all main meals in the combination.

One-year efficacy and safety of a fixed combination of insulin degludec and liraglutide in patients with type 2 diabetes: results of a 26-week extension to a 26-week main trial

AIMS

To confirm, in a 26-week extension study, the sustained efficacy and safety of a fixed combination of insulin degludec and liraglutide (IDegLira) compared with either insulin degludec or liraglutide alone, in patients with type 2 diabetes.

METHODS

Insulin-naïve adults with type 2 diabetes randomized to once-daily IDegLira, insulin degludec or liraglutide, in addition to metformin ± pioglitazone, continued their allocated treatment in this preplanned 26-week extension of the DUAL I trial.

RESULTS

A total of 78.8% of patients (1311/1663) continued into the extension phase. The mean glycated haemoglobin (HbA1c) concentration at 52 weeks was reduced from baseline by 1.84% (20.2 mmol/mol) for the IDegLira group, 1.40% (15.3 mmol/mol) for the insulin degludec group and 1.21% (13.2 mmol/mol) for the liraglutide group. Of the patients on IDegLira, 78% achieved an HbA1c of <7% (53 mmol/mol) versus 63% of the patients on insulin degludec and 57% of those on liraglutide. The mean fasting plasma glucose concentration at the end of the trial was similar for IDegLira (5.7 mmol/l) and insulin degludec (6.0 mmol/l), but higher for liraglutide (7.3 mmol/l). At 52 weeks, the daily insulin dose was 37% lower with IDegLira (39 units) than with insulin degludec (62 units). IDegLira was associated with a significantly greater decrease in body weight (estimated treatment difference, -2.80 kg, p < 0.0001) and a 37% lower rate of hypoglycaemia compared with insulin degludec. Overall, all treatments were well tolerated and no new adverse events or tolerability issues were observed for IDegLira.

CONCLUSIONS

These 12-month data, derived from a 26-week extension of the DUAL I trial, confirm the initial 26-week main phase results and the sustainability of the benefits of IDegLira compared with its components in glycaemic efficacy, safety and tolerability.

Is insulin the most effective injectable antihyperglycaemic therapy?

AIMS

The recent type 2 diabetes American Diabetes Association/European Association for the Study of Diabetes (ADA/EASD) position statement suggested insulin is the most effective glucose-lowering therapy, especially when glycated haemoglobin (HbA1c) is very high. However, randomized studies comparing glucagon-like peptide-1 receptor agonists (GLP-1RAs) exenatide once-weekly [OW; DURATION-3 (Diabetes therapy Utilization: Researching changes in A1c, weight, and other factors Through Intervention with exenatide ONce-Weekly)] and liraglutide once-daily [OD; LEAD-5 (Liraglutide Effect and Action in Diabetes)] with insulin glargine documented greater HbA1c reduction with GLP-1RAs, from baseline HbA1c ∼8.3% (67 mmol/mol). This post hoc analysis of DURATION-3 and LEAD-5 examined changes in HbA1c, fasting glucose and weight with exenatide OW or liraglutide and glargine, by baseline HbA1c quartile.

METHODS

Descriptive statistics were provided for change in HbA1c, fasting glucose, weight, and insulin dose, and subjects (%) achieving HbA1c <7.0%, by baseline HbA1c quartile. Inferential statistical analysis on the effect of baseline HbA1c quartile was performed for change in HbA1c. An analysis of covariance (ANCOVA) model was used to evaluate similarity in change in HbA1c across HbA1c quartiles.

RESULTS

At 26 weeks, in both studies, HbA1c reduction, and proportion of subjects reaching HbA1c <7.0%, were similar or numerically greater with the GLP-1RAs than glargine for all baseline HbA1c quartiles. Fasting glucose reduction was similar or numerically greater with glargine. Weight decreased with both GLP-1RAs across all quartiles; subjects taking glargine gained weight, more at higher baseline HbA1c. Adverse events were uncommon although gastrointestinal events occurred more frequently with GLP-1RAs.

CONCLUSIONS

HbA1c reduction with the GLP-1RAs appears at least equivalent to that with basal insulin, irrespective of baseline HbA1c. This suggests that liraglutide and exenatide OW may be appropriate alternatives to basal insulin in type 2 diabetes, including when baseline HbA1c is very high (≥9.0%).

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.

Exendin-4 promotes endothelial barrier enhancement via PKA- and Epac1-dependent Rac1 activation

Among emerging antidiabetic agents, glucagon-like peptide-1 (GLP-1)-based therapies carry special cardiovascular implications, exerting both direct and indirect effects. The control of vascular permeability is of pivotal importance in vascular pathologies. The objective of the present study was to determine the effect of GLP-1 on endothelial barrier function and assess the underlying mechanism(s). Here we show for the first time that the stable GLP-1 analog exendin-4 attenuated the leakage of subcutaneous blood vessels in mice indexed by dye extravasation caused by injections of thrombin. Moreover, in cultured endothelial cells, exendin-4 significantly prevented the thrombin-induced FITC-dextran permeability of endothelial monolayers via GLP-1 receptor. Immunofluorescence microscopy reveals that exendin-4 abrogates detrimental effects of thrombin on VE-cadherin and the F-actin cytoskeleton, with decreased stress fiber and gap formation. Importantly, exendin-4 reduced thrombin-induced tyrosine phosphorylation of VE-cadherin at Y731 and Y658. Moreover, small GTPase Rac1 was significantly activated as a result of exendin-4 treatment. The efficacy of exendin-4 to counteract the barrier-compromising effect of thrombin was blunted when Rac1 was inactivated by Rac1 inhibitor NSC-23766. Inhibition of PKA activity or small-interfering RNA for exchange protein directly activated by cAMP 1 (Epac1) decreased exendin-4-induced Rac1 activation and barrier enhancement, indicating the participation of both PKA and Epac1 in the barrier-stabilizing effect of exendin-4 elicited on thrombin-impaired barrier function. Thus, our findings have uncovered an unpredicted role for exendin-4 in the coordination of vascular permeability and clarified the molecular underpinnings that contribute to barrier restoration initiated by exendin-4.