Efficacy of Exenatide Plus Pioglitazone Vs Basal/Bolus Insulin in T2DM Patients With Very High HbA1c

A Randomized Controlled Trial Comparing the Efficacy and Safety of IDegLira Versus Basal-Bolus in Patients With Poorly Controlled Type 2 Diabetes and Very High HbA1c ≥9-15%: DUAL HIGH Trial

OBJECTIVE

In participants with type 2 diabetes (T2D) and HbA1c >9.0-10.0%, guidelines recommend treatment with basal-bolus insulin.

RESEARCH DESIGN AND METHODS

This randomized trial compared the efficacy and safety of insulin degludec and liraglutide (IDegLira) and basal-bolus among participants with high HbA1c ≥9.0-15.0%, previously treated with 2 or 3 oral agents and/or basal insulin, allocated (1:1) to basal-bolus (n = 73) or IDegLira (n = 72). The primary end point was noninferiority (0.4%) in HbA1c reduction between groups.

RESULTS

Among 145 participants (HbA1c 10.8% ± 1.3), there was no statistically significant difference in HbA1c reduction (3.18% ± 2.29 vs. 3.00% ± 1.79, P = 0.65; estimated treatment difference (ETD) 0.18%, 95% CI -0.59, 0.94) between the IDegLira and basal-bolus groups. IDegLira resulted in significantly lower rates of hypoglycemia <70 mg/dL (26% vs. 48%, P = 0.008; odds ratio 0.39, 95% CI 0.19, 0.78), and less weight gain (1.24 ± 8.33 vs. 5.84 ± 6.18 kg, P = 0.001; ETD -4.60, 95% CI -7.33, -1.87).

CONCLUSIONS

In participants with T2D and HbA1c ≥9.0-15.0%, IDegLira resulted in similar HbA1c reduction, less hypoglycemia, and less weight gain compared with the basal-bolus regimen.

Personalized approach for type 2 diabetes pharmacotherapy: where are we and where do we need to be?

INTRODUCTION

Cluster analysis has identified distinct groups of type 2 diabetes (T2D) subjects with distinct metabolic characteristics. Thus, personalizing pharmacologic therapy to individual phenotypic and pathophysiologic characteristics has potential to improve metabolic control and reduce risk of microvascular and macrovascular complications.

AREAS COVERED

The authors review the classification of T2D, genetic markers, pathophysiology and natural history of T2D, the ABCDE approach to therapy, the ADA/EASD stepwise approach to therapy, available antidiabetic agents, and provide a more rational therapeutic approach based upon pathophysiology and cardiovascular and renal outcome trials.

EXPERT OPINION

Although insulin resistance is the earliest detectable abnormality, overt T2D does not occur in the absence of progressive beta cell failure. Because of the complex etiology of T2D (Ominous Octet), initiation of therapy with combined agents that (i) target both insulin resistance and beta cell dysfunction and (ii) prevent macrovascular, as well as microvascular, complications will be required. The ratio of C-peptide at 120 minutes (OGTT) to baseline C-peptide predicts with high sensitivity who will respond to metformin, the response to glucose-lowering agents and provides a useful tool to guide optimal glucose lowering therapy.

Insulin secretion is a strong predictor for need of insulin therapy in patients with new-onset diabetes and HbA1c of more than 10%: A post hoc analysis of the EDICT study

AIM

To identify predictors of response to glucose-lowering therapy in patients with new-onset diabetes and very high HbA1c (>10%).

METHODS

The study included EDICT participants with an initial HbA1c of more than 10% (N = 104). All subjects received a 75-g oral glucose tolerance test (OGTT) before initiation of therapy, and then were randomized to receive: (a) initial triple therapy with metformin, pioglitazone and exenatide versus (b) stepwise conventional therapy with metformin followed by glipizide and then glargine insulin to reduce HbA1c to less than 6.5%. Insulin secretion and insulin resistance were calculated with OGTT-derived indices.

RESULTS

Sixty-one per cent of participants in the conventional therapy group achieved HbA1c of less than 6.5% at 6 months without need of insulin therapy compared with 78% in the triple therapy group (P = NS). Insulin secretion at baseline was the strongest predictor of subjects who did not require insulin therapy; a cut point of CPEP₁₂₀ /CPEP₀ -the ratio between plasma C-peptide concentration at 120 minutes during the OGTT and fasting plasma C-peptide concentration-of more than 1.7 predicted subjects who achieved the treatment target without insulin, irrespective of the fasting plasma glucose (FPG) concentration and whether or not they were started on conventional or triple therapy. Subjects with a CPEP₁₂₀ /CPEP₀ of less than 1.7 plus FPG of 269 mg/dL or less (≤14.9 mmoL/L) also achieved the treatment goal with triple therapy.

CONCLUSION

Insulin secretion in response to a 75-g OGTT predicts the need for insulin therapy at the time of type 2 diabetes (T2D) diagnosis. A cut point of 1.7 of CPEP₁₂₀ /CPEP₀ provides a useful clinical tool to individualize glucose-lowering therapy in patients with new-onset T2D and HbA1c of more than 10%.

Durability of Triple Combination Therapy Versus Stepwise Addition Therapy in Patients With New-Onset T2DM: 3-Year Follow-up of EDICT

OBJECTIVE

To compare the long-term efficacy of initiating therapy with metformin/pioglitazone/exenatide in patients with new-onset type 2 diabetes mellitus (T2DM) versus sequential addition of metformin followed by glipizide and insulin.

RESEARCH DESIGN AND METHODS

Drug-naive patients (N = 318) with new-onset T2DM were randomly assigned to receive for 3 years either 1) combination therapy with metformin, pioglitazone, and exenatide (triple therapy) or 2) sequential addition of metformin followed by glipizide and insulin (conventional therapy) to maintain HbA_1c at <6.5% (48 mmol/mol). Insulin sensitivity and β-cell function were measured at baseline and 3 years. The primary outcome was the difference in HbA_1c between the groups at 3 years.

RESULTS

Baseline HbA_1c ± SEM values were 9.0% ± 0.2% and 8.9% ± 0.2% in the triple therapy and conventional therapy groups, respectively. The decrease in HbA_1c resulting from triple therapy was greater at 6 months than that produced by conventional therapy (0.30% [95% CI 0.21-0.39]; P = 0.001), and the HbA_1c reduction was maintained at 3 years in patients receiving triple therapy compared with conventional therapy (6.4% ± 0.1% and 6.9% ± 0.1%, respectively), despite intensification of antihyperglycemic therapy in the latter. Thus, the difference in HbA_1c between the two treatment groups at 3 years was 0.50% (95% CI 0.39-0.61; P < 0.0001). Triple therapy produced a threefold increase in insulin sensitivity and 30-fold increase in β-cell function. In conventional therapy, insulin sensitivity did not change and β-cell function increased by only 34% (both P < 0.0001 vs. triple therapy).

CONCLUSIONS

Triple therapy with agents that improve insulin sensitivity and β-cell function in patients with new-onset T2DM produces greater, more durable HbA_1c reduction than agents that lower glucose levels without correcting the underlying metabolic defects.

Clinical pharmacology of glucagon-like peptide-1 receptor agonists

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are an important asset in the armamentarium for the treatment of type 2 diabetes mellitus (type 2 DM). Incretin failure is a critical etiopathogenetic feature of type 2 DM, which, if reversed, results in improved glycaemic control. GLP-1 RAs are injectable peptides that resemble the structure and function of endogenous incretin GLP-1, but as they are not deactivated by the dipeptidyl peptidase-4 (DPP-4), their half-life is prolonged compared with native GLP-1. Based on their ability to activate GLP-1 receptor, GLP-1 RAs are classified as short-acting (exenatide twice-daily and lixisenatide once-daily), and long-acting (liraglutide once-daily and the once-weekly formulations of exenatide extended-release, dulaglutide, and albiglutide). Semaglutide, another long-acting, once-weekly GLP-1 RA, was recently approved by the FDA and EMA. Although all of these agents potently reduce haemoglobin A1C (HbA1c), there are unique features and fundamental differences among them related to fasting and postprandial hyperglycaemia reduction, weight loss potency, cardiovascular protection efficacy, and adverse events profile. It is imperative that current evidence be integrated and applied in the context of an individualised patient-centred approach. This should include not only glucose management but also targeting as many as possible of the pathophysiologic mechanisms responsible for type 2 DM development and progression.

Insulin secretion predicts the response to therapy with exenatide plus pioglitazone, but not to basal/bolus insulin in poorly controlled T2DM patients: Results from the Qatar study

The present study aims to identify predictors for response to combination therapy with pioglitazone plus exenatide vs basal/bolus insulin therapy in T2DM patients who are poorly controlled with maximum/near-maximum doses of metformin plus a sulfonylurea. Participants in the Qatar study received a 75-g OGTT with measurement of plasma glucose, insulin and C-peptide concentration at baseline and were then randomized to receive either treatment with pioglitazone plus exenatide or basal/bolus insulin therapy for one year. Insulin secretion measured with plasma C-peptide concentration during the OGTT was the strongest predictor of response to combination therapy (HbA1c ≤ 7.0%) with pioglitazone plus exenatide. A 54% increase in 2-hour plasma C-peptide concentration above the fasting level identified subjects who achieved the glycaemic goal (HbA1c < 7.0%) with 82% sensitivity and 79% specificity. Only baseline HbA1c was a predictor of response to basal/bolus insulin therapy. Thus, the increment in 2-hour plasma C-peptide concentration above the fasting level provides a useful tool to identify poorly controlled T2DM patients who can achieve glycaemic control without insulin therapy, and thereby, can be used to individualize antihyperglycaemic therapy in poorly controlled T2DM patients.

Exenatide induces carcinoembryonic antigen-related cell adhesion molecule 1 expression to prevent hepatic steatosis

Exenatide, a glucagon-like peptide-1 receptor agonist, induces insulin secretion. Its role in insulin clearance has not been adequately examined. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes hepatic insulin clearance to maintain insulin sensitivity. Feeding C57BL/6J mice a high-fat diet down-regulates hepatic Ceacam1 transcription to cause hyperinsulinemia, insulin resistance, and hepatic steatosis, as in Ceacam1 null mice (Cc1^-/- ). Thus, we tested whether exenatide regulates Ceacam1 expression in high-fat diet-fed mice and whether this contributes to its insulin sensitizing effect. Exenatide (100 nM) induced the transcriptional activity of wild-type Ceacam1 promoter but not the constructs harboring block mutations of peroxisome proliferator-activated receptor response element and retinoid X receptor alpha, individually or collectively, in HepG2 human hepatoma cells. Chromatin immunoprecipitation analysis demonstrated binding of peroxisome proliferator-activated receptor gamma to Ceacam1 promoter in response to rosiglitazone and exenatide. Consistently, exenatide induced Ceacam1 messenger RNA expression within 12 hours in the absence but not in the presence of the glucagon-like peptide-1 receptor antagonist exendin 9-39. Exenatide (20 ng/g body weight once daily intraperitoneal injection in the last 30 days of feeding) restored hepatic Ceacam1 expression and insulin clearance to curb diet-induced metabolic abnormalities and steatohepatitis in wild-type but not Cc1^-/- mice fed a high-fat diet for 2 months. Conclusion: Exenatide promotes insulin clearance in parallel with insulin secretion to prevent chronic hyperinsulinemia and the resulting hepatic steatosis, and this contributes to its insulin sensitizing effect. Our data further highlight the relevance of physiologic insulin metabolism in maintaining insulin sensitivity and normal lipid metabolism. (Hepatology Communications 2018;2:35-47).

Combination therapy with GLP-1 receptor agonist and SGLT2 inhibitor

The SGLT2 inhibitors (SGLTi) and glucagon-like-1 receptor agonists (GLP-1 RAs) effectively reduce HbA1c, but via very different mechanisms, making them an effective duet for combination therapy. Recently, drugs in both of these antidiabetic classes have been shown to reduce cardiovascular events, most probably by different mechanisms. SGLT2i appear to exert their CV protective actions by haemodynamic effects, while GLP-1 RAs work via anti-atherogenic/anti-inflammatory mechanisms, raising the possibility that combined therapy with these 2 classes may produce additive CV benefits. The SGLT2i and GLP-1 RAs also reduced macroalbuminuria, decreased the time for doubling of serum creatinine, and slowed the time to end-stage renal disease. In this perspective, we review the potential benefit of combination SGLT2i/GLP-1 RA therapy on metabolic-cardiovascular-renal disease in patients with type 2 diabetes mellitus.

Is insulin the preferred treatment for HbA1c >9%?

The algorithms and guidelines of the American Association of Clinical Endocrinologists and the American Diabetes Association recommend that insulin administration be strongly considered for people with type 2 diabetes (T2D) with HbA1c levels exceeding 9.0% and 10%, respectively. Although the caveat is given in both sets of recommendations that this is particularly appropriate when patients are "symptomatic," referring to urinary frequency with increased thirst and appetite, weight loss, and ketosis, the clinical definition of such presentations may be ill-defined, and it is noteworthy that both documents consider insulin to offer particular benefit under such circumstances. However, with multiple options for glycemic treatment, it is of interest to reconsider this argument for insulin use. It should be recalled that in the UK Prospective Diabetes Study, diet alone was associated with a reduction in HbA1c from 9% to 7%. Drug-naïve people with T2D do often show surprisingly strong reductions in HbA1c with metformin-based dual-agent oral treatment approaches; a recent report showed that even with baseline HbA1c >11%, the combination of metformin with a sulfonylurea, pioglitazone, or sitagliptin was associated with reduction in HbA1c from 11.6% to 6.0%. A 32-week study of the combination of rosiglitazone with metformin in patients with mean baseline HbA1c 8.9% showed a mean HbA1c reduction of 2.3%, and an open-label cohort with baseline HbA1c 11.8% had a reduction in HbA1c to 7.8%. With metformin plus sitagliptin, a mean placebo-adjusted HbA1c reduction of 2.1% from a baseline of 8.8% was reported, with those patients with baseline HbA1c >9% having a 2.6% reduction in HbA1c, and an open-label cohort with baseline HbA1c 11.2% having a 2.9% reduction in HbA1c. Similar 2% HbA1c reductions from baseline levels of 9.1% were seen with metformin in initial combination with the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin. Although such dual oral agent approaches are more effective than monotherapy, with a combination regimen the HbA1c reduction will not be directly additive, because the expected reduction decreases at lower baseline HbA1c levels. As an example of this, administration of canagliflozin 300 mg daily to patients with baseline HbA1c >9% reduced levels from 9.6% by 1.8%, whereas at a baseline HbA1c of 10% either canagliflozin 300 mg or metformin 2 g/day reduced HbA1c by 2%; the addition of both agents led to an HbA1c reduction by somewhat less than 3%, which appears concordant with a reduction by the second agent from approximately 8% (10% to 2%). Similar less-than-additive effects of the addition of exenatide QW to dapagliflozin have been reported, with HbA1c reduction from a baseline of 10.0%-10.1% of 1.9% and 1.6% with the individual agents, respectively, and a reduction of 2.2% with their combination. However, one may consider these approaches inferior to the expected HbA1c reduction with insulin, suggesting that insulin should, indeed, be the preferred treatment for people with T2D and HbA1c >9%. Rather, studies comparing basal insulin directly with glucagon-like peptide-1 (GLP-1) receptor agonists (RA) suggest that the latter agents may offer superior benefit. The Diabetes Therapy Utilization: Researching Changes in HBA1C, Weight, and Other Factors Through Intervention with Exenatide Once Weekly (DURATION)-3 and Liraglutide Effect and Action in Diabetes (LEAD)-5 studies compared exenatide QW and liraglutide, respectively, with insulin glargine. Those study participants in the highest quartile of baseline HbA1c had levels ≥9.0% and ≥8.9%, with the GLP-1RA leading to 0.3% and 0.2% greater reductions in HbA1c, respectively, than insulin glargine. Another study comparing T2D patients receiving oral agents given liraglutide with those given insulin glargine showed that those in the highest baseline HbA1c quartile (mean 10.6%) had an HbA1c reduction of 3.1% with either agent. In the exenatide QW study, the reduction in HbA1c with this agent exceeded that with insulin glargine for those groups of study participants with HbA1c 9.0%-9.4%, 9.5%-9.9%, 10.0%-10.4%, 10.5%-10.9%, and even ≥11.0%. Similar superiority of the HbA1c-lowering effect of exenatide QW compared with that of insulin glargine was reported in a study with baseline HbA1c 8.5%. An individual-patient meta-analysis of six studies of another weekly GLP-1RA, namely dulaglutide, showed that at a baseline HbA1c of 10% the expected HbA1c reduction would be nearly 2.5%, and a study directly comparing dulaglutide with insulin glargine also showed a superior HbA1c-lowering effect of the former. Another advantage of the GLP-1RAs is their association with weight loss, rather than the weight gain associated with insulin treatment. An interesting potential combination is that of a GLP-1RA with a thiazolidinedione. In a study comparing the addition of exenatide QW and pioglitazone with the addition of basal-bolus insulin in 101 people receiving sulfonylureas and metformin with baseline HbA1c >10%, HbA1c fell from >11% by >4% compared with <4%, respectively, and the GLP-1RA plus thiazolidinedione treatment was associated with less weight gain and hypoglycemia. What can we conclude? Should HbA1c 11% be the new "use insulin" point? Insulin is an important part of our armamentarium for T2D, and is certainly needed for many patients, but with current therapeutic approaches including metformin, incretin-based treatments, SGLT2 inhibitors, and, possibly, thiazolidinediones, we can reconsider its use in many instances. Although there is no doubt that insulin is necessary for truly uncontrolled diabetes, we may wish to better define its correct indications.