Randomised comparison of intravenous and subcutaneous routes of glucagon-like peptide-1 administration for lowering plasma glucose in hyperglycaemic subjects with type 2 diabetes.

AIM: To perform a direct, double-blind, randomised, crossover comparison of subcutaneous and intravenous glucagon-like peptide-1 (GLP-1) in hyperglycaemic subjects with type 2 diabetes naïve to GLP-1-based therapy. MATERIALS AND METHODS: Ten fasted, hyperglycaemic subjects (1 female, age 63 ± 10 years [mean ± SD], glycated haemoglobin 73.5 ± 22.0 mmol/mol [8.9% ± 2.0%], both mean ± SD) received subcutaneous GLP-1 and intravenous saline, or intravenous GLP-1 and subcutaneous saline. Infusion rates were doubled every 120 min (1.2, 2.4, 4.8 and 9.6 pmol·kg-1·min-1 for subcutaneous, and 0.3, 0.6, 1.2 and 2.4 pmol·kg-1·min-1 for intravenous). Plasma glucose, total and intact GLP-1, insulin, C-peptide, glucagon and gastrointestinal symptoms were evaluated over 8 h. The results are presented as mean ± SEM. RESULTS: Plasma glucose decreased more with intravenous (by ~8.0 mmol/L [144 mg/dL]) than subcutaneous GLP-1 (by ~5.6 mmol/L [100 mg/dL]; p < 0.001). Plasma GLP-1 increased dose-dependently, but more with intravenous than subcutaneous for both total (∆max 154.2 ± 3.9 pmol/L vs. 85.1 ± 3.8 pmol/L; p < 0.001), and intact GLP-1 (∆max 44.2 ± 2.2 pmol/L vs. 12.8 ± 2.2 pmol/L; p < 0.001). Total and intact GLP-1 clearance was higher for subcutaneous than intravenous GLP-1 (p < 0.001 and p = 0.002, respectively). The increase in insulin secretion was greater, and glucagon was suppressed more with intravenous GLP-1 (p < 0.05 each). Gastrointestinal symptoms did not differ (p > 0.05 each). CONCLUSIONS: Subcutaneous GLP-1 administration is much less efficient than intravenous GLP-1 in lowering fasting plasma glucose, with less stimulation of insulin and suppression of glucagon, and much less bioavailability, even at fourfold higher infusion rates.

The importance of glucose-dependent insulinotropic polypeptide receptor activation for the effects of tirzepatide.

Tirzepatide is a unimolecular co-agonist of the glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors recently approved for the treatment of type 2 diabetes by the US Food and Drug Administration and the European Medicine Agency. Tirzepatide treatment results in an unprecedented improvement of glycaemic control and lowering of body weight, but the contribution of the GIP receptor-activating component of tirzepatide to these effects is uncertain. In this review, we present the current knowledge about the physiological roles of the incretin hormones GLP-1 and GIP, their receptors, and previous results of co-targeting the two incretin hormone receptors in humans. We also analyse the molecular pharmacological, preclinical and clinical effects of tirzepatide to discuss the role of GIP receptor activation for the clinical effects of tirzepatide. Based on the available literature on the combination of GLP-1 and GIP receptor activation, tirzepatide does not seem to have a classical co-activating mode of action in humans. Rather, in vitro studies of the human GLP-1 and GIP receptors reveal a biased GLP-1 receptor activation profile and GIP receptor downregulation. Therefore, we propose three hypotheses for the mode of action of tirzepatide, which can be addressed in future, elaborate clinical trials.

Safety and tolerability of semaglutide across the SUSTAIN and PIONEER phase IIIa clinical trial programmes.

AIM: Glucagon-like peptide-1 receptor agonists improve glycaemic control: some are now available as oral and subcutaneous formulations, and some have indications for reducing cardiovascular risk. The expanded scope for these therapies warrants comprehensive safety evaluations. We report the safety/tolerability of subcutaneous and oral semaglutide from the SUSTAIN and PIONEER clinical trial programmes, respectively. MATERIALS AND METHODS: Adverse events (AEs) from 16 randomized placebo- or active-controlled phase IIIa trials in patients with type 2 diabetes (n = 11 159) including once-weekly subcutaneous semaglutide (n = 3150; SUSTAIN trials) or once-daily oral semaglutide (n = 4116; PIONEER trials) were analysed. Data pools were analysed for each programme, with separate analyses of cardiovascular outcomes trials (CVOTs; n = 6480). RESULTS: In the phase IIIa pools, gastrointestinal disorders were reported in 41.9%/39.1% of patients with subcutaneous/oral semaglutide, respectively (most prevalent during initiation/escalation) versus 22.0%/24.8% with comparators. Rates of kidney disorders, acute pancreatitis, malignant neoplasms, hypoglycaemia, diabetic retinopathy, heart failure and other cardiovascular events were similar for semaglutide versus comparators. Cholelithiasis incidence was higher with subcutaneous and oral semaglutide versus placebo. Diabetic retinopathy incidence was higher with subcutaneous semaglutide versus placebo in SUSTAIN 6. Small pulse rate increases occurred with both formulations; there was no increased rate of arrhythmias. Fatal AE incidence was similar between semaglutide and comparators. Versus placebo, CVOTs showed a reduced risk of major adverse cardiovascular events with subcutaneous semaglutide and non-inferiority criteria were met with oral semaglutide. CONCLUSIONS: The most common AEs with semaglutide were gastrointestinal disorders, which decreased with continued therapy. These comprehensive safety/tolerability data may better inform patient selection and guidance in care.

Microbiome composition and central serotonergic activity in patients with depression and type 1 diabetes.

The role of gut-brain axis functioning gains growing attention in research on the pathophysiology of major depressive disorders. Here, especially consequences of altered microbiota composition on tryptophan metabolism resulting in altered serotonergic neurotransmission in the central nervous system (CNS) have reached a central position. Previous research, however, mainly focused on either microbiota and peripheral serotonin levels or central serotonergic neurotransmission. The present study aimed to combine the analysis of microbiota composition and central serotonergic activity using a valid neurophysiological indicator. We recruited 19 adult patients with type 1 diabetes and depression (D + D; 7 males), 19 patients with type 1 diabetes (D-; 7 male), and 20 healthy participants (HC; 7 males). Next to the analysis of fecal microbiota regarding α- and ß-diversity, the loudness dependence of auditory evoked potential (LDAEP) was investigated, a non-invasive measurement of central serotonergic activity. High α-diversity was associated with high LDAEP, i.e., low serotonergic activity, in patients with diabetes and additional depression. Furthermore, relative abundances of bacterial families belonging to Bacteroidetes, Proteobacteria and Firmicutes were shown to have an impact on central serotonergic activity. This finding was supported by a tendency indicating an association of central serotonergic activity with the Bacteroidetes-Firmicutes ratio in both patients' groups. Together, this data suggests that the guts' microbiota composition might play an important role in regulating the central serotonergic activity in the brain.

Gut microbiota differs in composition between adults with type 1 diabetes with or without depression and healthy control participants: a case-control study.

BACKGROUND: Individuals with type 1 diabetes and those with depression show differences in the composition of the gut microbiome from that of healthy people. However, these differences have not yet been studied in patients with both diseases. Therefore, we compared the gut microbiome of people with type 1 diabetes with or without depression with matched healthy controls. METHODS: A case-control study was conducted in 20 adults with type 1 diabetes (group A), 20 adults with type 1 diabetes and depression (group B), and 20 healthy adults (group C). Gut microbiota composition was determined by sequencing of the V3-V4 region of the bacterial 16S rDNA and alpha and beta diversity was compared between the groups. RESULTS: Groups A and B both showed higher alpha diversity than the healthy control group (P < 0.001) but alpha diversity did not differ significantly between groups A and B. Participants having type 1 diabetes with (P < 0.05) or without comorbid depression (P < 0.001) differed regarding beta diversity from healthy controls but not between each other. Group B (diabetes with depression) had significantly higher abundance of Megaspaera than groups A and C. Both diabetes groups had a higher abundance of Christensenellaceae, Succinivibrionaceae, and Rhodospirillaceae than the healthy group but similar between-group abundances. CONCLUSIONS: While differences in alpha and beta diversity and in some bacterial taxa occurred only between participants with diabetes and healthy controls, specific characteristics regarding the abundance of Megasphaera were observed in people with diabetes and comorbid depression. In summary, the study findings indicate a possible involvement of bacterial groups in depression in people with diabetes. The results suggest replication studies in larger samples to verify these findings.

Efficacy and safety of oral semaglutide by subgroups of patient characteristics in the PIONEER phase 3 programme.

AIMS: To evaluate the efficacy and safety of oral semaglutide versus comparators by patient characteristic subgroups in patients with type 2 diabetes. MATERIALS AND METHODS: Change from baseline in glycated haemoglobin (HbA1c) and body weight, and achievement of HbA1c <7.0% with oral semaglutide 7 mg, oral semaglutide 14 mg, flexibly dosed oral semaglutide (flex) and comparators were assessed across baseline subgroups (age, race, ethnicity, diabetes duration, body mass index and HbA1c) from the PIONEER programme. Treatment differences were analysed using a mixed model for repeated measurements for continuous variables and a logistic regression model for the binary endpoint. Pooled safety data were analysed descriptively. RESULTS: Changes from baseline in HbA1c and body weight, and the odds of achieving HbA1c <7.0%, were greater with oral semaglutide 14 mg/flex (n = 1934) and higher or similar with oral semaglutide 7 mg (n = 823) versus comparators (n = 2077) across most subgroups. Changes in HbA1c with oral semaglutide 14 mg/flex were greater for patients with higher baseline HbA1c (HbA1c >9.0%: -1.7% to -2.6%; HbA1c <8.0%: -0.7% to -1.2%). In some trials, Asian patients experienced greater HbA1c reductions with oral semaglutide 14 mg/flex (-1.5% to -1.8%) than other racial groups (-0.6% to -1.6%). The overall incidence of adverse events (AEs) with oral semaglutide was similar to that with comparators and was consistent across subgroups. More gastrointestinal AEs were observed with oral semaglutide, versus comparators, across subgroups. CONCLUSIONS: Oral semaglutide demonstrated consistently greater HbA1c and body weight reductions across a range of patient characteristics, with greater HbA1c reductions seen at higher baseline HbA1c levels.

Effect of upper gastrointestinal disease on the pharmacokinetics of oral semaglutide in subjects with type 2 diabetes.

AIM: To investigate whether upper gastrointestinal (GI) disease has any effect on the exposure of oral semaglutide, an important consideration given that its absorption occurs primarily in the stomach. MATERIALS AND METHODS: In an open-label, parallel-group trial (NCT02877355), subjects aged 18-80 years with type 2 diabetes with mild-to-moderate upper GI disease (N = 36; chronic gastritis [n = 5], gastroesophageal reflux disease [n = 8], and both [n = 23]) or without upper GI disease (N = 19) received oral semaglutide 3 mg once daily for 5 days, followed by 7 mg for 5 days. The primary and key supportive endpoints were the area under the semaglutide plasma concentration-time curve (AUC) from 0 to 24 hours after last trial product administration on day 10 (AUC0-24h,day10 ) and the maximum semaglutide plasma concentration (Cmax,day10 ), respectively. RESULTS: Semaglutide exposure was not statistically significantly different between subjects with and without upper GI disease. Estimated group ratios (subjects with/without upper GI disease) were 1.18 (95% confidence interval [CI], 0.80, 1.75) for AUC0-24h,day10 and 1.16 (95% CI, 0.77, 1.76) for Cmax . Time to Cmax and semaglutide half-life were similar in subjects with and without upper GI disease. Oral semaglutide was well tolerated; all adverse events were mild-to-moderate, with no withdrawals because of adverse events. CONCLUSIONS: There was no significant difference in exposure to oral semaglutide in subjects with or without upper GI disease, hence no dose adjustment is required.

Acute effects of linagliptin on intact and total glucagon-like peptide-1 and gastric inhibitory polypeptide levels in insulin-dependent type 2 diabetes patients with and without moderate renal impairment.

AIMS: To investigate the effect of renal impairment on incretin metabolism in patients with type 2 diabetes mellitus (T2DM) before and after treatment with the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin. MATERIALS AND METHODS: Long-standing T2DM patients with normal (estimated glomerular filtration rate [eGFR] >90 mL/min/1.73m2 ) and impaired (eGFR <60 mL/min/1.73m2 ) renal function on stable treatment with insulin were included. Before and after 8 days of treatment with 5 mg linagliptin once daily, patients underwent a 75-g oral glucose tolerance test (OGTT) and total and intact glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP), glucose, insulin, C-peptide and glucagon concentrations were measured. The primary outcome was the difference between the study groups in change of intact GLP-1 concentrations. RESULTS: Of 115 patients screened, 29 were analysed (15 [51.7%] with and 14 [48.3%] without renal impairment). Renal function differed significantly between the groups (101 ± 11 vs. 47 ± 13 mL/min/1.73m2 ; P < 0.0001), while glycaemic control was similar (glycated haemoglobin 68 ± 5 vs. 66 ± 5 mmol/mol; P = 0.45). Baseline GLP-1 and GIP levels were comparable. Glucose concentrations during the OGTT were significantly lowered by linagliptin treatment in patients with renal impairment (P = 0.017), but not in those with normal renal function (P = 0.17). Treatment with linagliptin resulted in a significant increase in intact GLP-1 and GIP levels in patients with normal (P = 0.048 and P = 0.0001, respectively) and impaired (P = 0.040 and P = 0.0011, respectively) renal function during the OGTT. However, the primary outcome (difference between the groups in change of intact GLP-1 concentrations) was not significant (P = 0.22). Overall, linagliptin was well tolerated. CONCLUSIONS: Treatment with linagliptin increases intact incretin levels in patients with T2DM. Impaired renal function does not compromise the effects of linagliptin on active or total incretin levels as well as on glucagon secretion. Thus, treatment with linagliptin is suitable for patients with T2DM, independently of renal function.

Macronutrient intake, appetite, food preferences and exocrine pancreas function after treatment with short- and long-acting glucagon-like peptide-1 receptor agonists in type 2 diabetes.

AIM: To clarify the distinct effects of a long-acting (liraglutide) and a short-acting (lixisenatide) glucagon-like peptide-1 receptor agonist (GLP-1 RA) on macronutrient intake, gastrointestinal side effects and pancreas function. MATERIALS AND METHODS: Fifty participants were randomized to either lixisenatide or liraglutide for a treatment period of 10 weeks. Appetite, satiety, macronutrient intake, gastrointestinal symptoms and variables related to pancreatic function and gastric emptying were assessed at baseline and after treatment. RESULTS: Both GLP-1 RAs reduced macronutrient intake similarly. Weight loss and appetite reduction were not related to the delay in gastric emptying or gastrointestinal side effects (P > .05). Lipase increased significantly with liraglutide treatment (by 18.3 ± 4.1 U/L; P = .0001), but not with lixisenatide (-1.8 ± 2.4 U/L; P = .46). Faecal elastase and serum ß-carotin levels (indicators for exocrine pancreas function) improved in both groups (P < .05). Changes in lipase activities did not correlate with gastrointestinal symptoms (P > .05 for each variable). CONCLUSIONS: Both GLP-1 RAs comparably affected body weight, energy and macronutrient intake. Both treatments were associated with indicators of improved exocrine pancreas function. Reductions in appetite and body weight as a result of treatment with short- or long-acting GLP-1 RAs are not driven by changes in gastric emptying or gastrointestinal side effects.

Oral semaglutide versus subcutaneous liraglutide and placebo in type 2 diabetes (PIONEER 4): a randomised, double-blind, phase 3a trial.

BACKGROUND: Glucagon-like peptide-1 (GLP-1) receptor agonists are effective treatments for type 2 diabetes, lowering glycated haemoglobin (HbA1c) and weight, but are currently only approved for use as subcutaneous injections. Oral semaglutide, a novel GLP-1 agonist, was compared with subcutaneous liraglutide and placebo in patients with type 2 diabetes. METHODS: In this randomised, double-blind, double-dummy, phase 3a trial, we recruited patients with type 2 diabetes from 100 sites in 12 countries. Eligible patients were aged 18 years or older, with HbA1c of 7·0-9·5% (53-80·3 mmol/mol), on a stable dose of metformin (≥1500 mg or maximum tolerated) with or without a sodium-glucose co-transporter-2 inhibitor. Participants were randomly assigned (2:2:1) with an interactive web-response system and stratified by background glucose-lowering medication and country of origin, to once-daily oral semaglutide (dose escalated to 14 mg), once-daily subcutaneous liraglutide (dose escalated to 1·8 mg), or placebo for 52 weeks. Two estimands were defined: treatment policy (regardless of study drug discontinuation or rescue medication) and trial product (assumed all participants were on study drug without rescue medication) in all participants who were randomly assigned. The treatment policy estimand was the primary estimand. The primary endpoint was change from baseline to week 26 in HbA1c (oral semaglutide superiority vs placebo and non-inferiority [margin: 0·4%] and superiority vs subcutaneous liraglutide) and the confirmatory secondary endpoint was change from baseline to week 26 in bodyweight (oral semaglutide superiority vs placebo and liraglutide). Safety was assessed in all participants who received at least one dose of study drug. This trial is registered on Clinicaltrials.gov, number NCT02863419, and the European Clinical Trials registry, number EudraCT 2015-005210-30. FINDINGS: Between Aug 10, 2016, and Feb 7, 2017, 950 patients were screened, of whom 711 were eligible and randomly assigned to oral semaglutide (n=285), subcutaneous liraglutide (n=284), or placebo (n=142). 341 (48%) of 711 participants were female and the mean age was 56 years (SD 10). All participants were given at least one dose of study drug, and 277 (97%) participants in the oral semaglutide group, 274 (96%) in the liraglutide group, and 134 (94%) in the placebo group completed the 52-week trial period. Mean change from baseline in HbA1c at week 26 was -1·2% (SE 0·1) with oral semaglutide, -1·1% (SE 0·1) with subcutaneous liraglutide, and -0·2% (SE 0·1) with placebo. Oral semaglutide was non-inferior to subcutaneous liraglutide in decreasing HbA1c (estimated treatment difference [ETD] -0·1%, 95% CI -0·3 to 0·0; p<0·0001) and superior to placebo (ETD -1·1%, -1·2 to -0·9; p<0·0001) by use of the treatment policy estimand. By use of the trial product estimand, oral semaglutide had significantly greater decreases in HbA1c than both subcutaneous liraglutide (ETD -0·2%, 95% CI -0·3 to -0·1; p=0·0056) and placebo (ETD -1·2%, -1·4 to -1·0; p<0·0001) at week 26. Oral semaglutide resulted in superior weight loss (-4·4 kg [SE 0·2]) compared with liraglutide (-3·1 kg [SE 0·2]; ETD -1·2 kg, 95% CI -1·9 to -0·6; p=0·0003) and placebo (-0·5 kg [SE 0·3]; ETD -3·8 kg, -4·7 to -3·0; p<0·0001) at week 26 (treatment policy). By use of the trial product estimand, weight loss at week 26 was significantly greater with oral semaglutide than with subcutaneous liraglutide (-1·5 kg, 95% CI -2·2 to -0·9; p<0·0001) and placebo (ETD -4·0 kg, -4·8 to -3·2; p<0·0001). Adverse events were more frequent with oral semaglutide (n=229 [80%]) and subcutaneous liraglutide (n=211 [74%]) than with placebo (n=95 [67%]). INTERPRETATION: Oral semaglutide was non-inferior to subcutaneous liraglutide and superior to placebo in decreasing HbA1c, and superior in decreasing bodyweight compared with both liraglutide and placebo at week 26. Safety and tolerability of oral semaglutide were similar to subcutaneous liraglutide. Use of oral semaglutide could potentially lead to earlier initiation of GLP-1 receptor agonist therapy in the diabetes treatment continuum of care. FUNDING: Novo Nordisk A/S.

Efficacy, safety and cardiovascular outcomes of once-daily oral semaglutide in patients with type 2 diabetes: The PIONEER programme.

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are recommended for glycaemic management in patients with type 2 diabetes (T2D). Oral semaglutide, the first oral GLP-1RA, has recently been approved for clinical use, based on the results of the randomized, Phase 3a Peptide InnOvatioN for Early diabEtes tReatment (PIONEER) clinical trials. The PIONEER programme tested oral semaglutide in patients with T2D of duration ranging from 3.5 to 15 years, from monotherapy through to insulin add-on, in global populations and two trials dedicated to Japanese patients. Outcomes (glycated haemoglobin [HbA1c] and body weight reduction, plus other relevant efficacy and safety endpoints) were tested against both placebo and active standard-of-care medications. A separate trial evaluated the cardiovascular safety of oral semaglutide in patients with T2D at high cardiovascular risk. Over periods of treatment up to 78 weeks, oral semaglutide 7 and 14 mg once daily reduced HbA1c and body weight across the spectrum of T2D, and improved other diabetes-related endpoints, such as fasting plasma glucose. Oral semaglutide provided significantly better efficacy than placebo and commonly used glucose-lowering medications from the dipeptidyl peptidase-4 inhibitor (sitagliptin) and sodium-glucose co-transporter-2 inhibitor (empagliflozin) classes, as well as the subcutaneous GLP-1RAs liraglutide and dulaglutide. Oral semaglutide was well tolerated in line with the known safety profile of GLP-1RAs, with transient gastrointestinal events being the most common side effects reported. Cardiovascular safety was demonstrated for oral semaglutide in patients with cardiovascular disease or high cardiovascular risk. The results of the PIONEER programme suggest that oral semaglutide is efficacious and well tolerated for glycaemic control of T2D. The availability of oral semaglutide may help to broaden treatment choice and facilitate adoption of earlier GLP-1RA treatment in the paradigm of T2D management.

Incretin-based glucose-lowering medications and the risk of acute pancreatitis and malignancies: a meta-analysis based on cardiovascular outcomes trials.

Some epidemiological data have suggested an elevated risk of acute pancreatitis and pancreatic cancer after exposure to glucagon-like peptide (GLP)-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors. Recently, such outcomes have been assessed and adjudicated as adverse events of special interest in cardiovascular outcomes studies. We performed a meta-analysis of cases of acute pancreatitis and pancreatic cancer as well as any malignant neoplasm reported in cardiovascular outcomes trials (CVOTs) with GLP-1 receptor agonists and DPP-4 inhibitors. The numbers of cases observed with active drug or placebo (both on a background of standard care) were related to patient-years of observation. Rate ratios and their confidence intervals were calculated for the individual agents as well as for the classes of GLP-1 receptor agonists and DPP-4 inhibitors. Neither data on individual CVOTs of GLP-1 receptor agonists nor their meta-analysis [rate ratio: 1.05 (0.78-1.41)] indicated a significantly elevated risk of acute pancreatitis. All individual DPP-4 inhibitors displayed a non-significant trend towards an increased risk of acute pancreatitis, which was significant in the meta-analysis [1.75 (1.14-2.70); P = 0.01]. Neither GLP-1 receptor agonists nor DPP-4 inhibitors were associated with a significantly elevated or reduced risk of pancreatic cancer or for the totality of all malignant neoplasms. Based on a large database of randomized, placebo-controlled, prospective cardiovascular outcomes studies with GLP-1 receptor agonists and DPP-4 inhibitors, no signal for pancreatic cancer or any malignant neoplasms were detected. However, a 75% risk increase for the development of an acute pancreatitis was seen in the meta-analysis of DPP-4 inhibitor CVOTs.

Effects of sequential treatment with lixisenatide, insulin glargine, or their combination on meal-related glycaemic excursions, insulin and glucagon secretion, and gastric emptying in patients with type 2 diabetes.

AIM: To examine the glucose-lowering mechanisms of the glucagon-like peptide-1 receptor agonist lixisenatide after two subsequent meals and in combination with basal insulin. MATERIALS AND METHODS: Twenty-eight metformin-treated patients with type 2 diabetes were randomly assigned to treatment sequences with either lixisenatide or insulin glargine alone for 4 weeks, and a combination of both treatments for 4 weeks. Metabolic examinations were performed before and after each treatment period following breakfast and a late lunch 8 hours later. RESULTS: Lixisenatide mainly reduced postprandial glycaemia, while insulin glargine mainly reduced fasting glucose after breakfast (P < 0.05). This was partially preserved after a late lunch (P < 0.05). After breakfast, lixisenatide reduced insulin secretion and glucagon levels significantly. These effects were lost after a late lunch. Insulin glargine did not significantly reduce glucagon or insulin secretion. Gastric emptying was slowed by lixisenatide, but not by insulin glargine after breakfast. After the late lunch, lixisenatide slightly accelerated gastric emptying. CONCLUSIONS: Lixisenatide decelerates gastric emptying after breakfast, thereby reducing glycaemic excursions, insulin secretion and glucagon levels. The glycaemic reduction persists until after a late lunch, despite accelerated gastric emptying. The combination with insulin glargine enhances the glucose-lowering effect because of complementary modes of action.

Heart failure and type 2 diabetes: From cardiovascular outcome trials, with hope.

An excess risk of heart failure (HF) persists in patients with type 2 diabetes (T2D) despite optimal control of an array of conventional risk factors, including hyperglycaemia. Twelve cardiovascular outcome trials (CVOTs) have been published to date, although none, with the exception of the DECLARE trial with dapagliflozin, has included HF as a primary endpoint. The four trials with dipeptidyl-peptidase inhibitors (DPP-4i) (SAVOR-TIMI 53 with saxagliptin, EXAMINE with alogliptin, TECOS with sitagliptin and CARMELINA with linagliptin) failed to show any significant effect on HF risk in patients with T2D, with the notable exception of saxagliptin which was associated with a 27% increased risk. Five completed CVOTs with the GLP-1 RAs lixisenatide (ELIXA), liraglutide (LEADER), semaglutide (SUSTAIN-6), exenatide once weekly (EXSCEL) and albiglutide (HARMONY) also failed to reveal any significant effect on HF risk. The three trials with sodium glucose co-transporter-2 inhibitors (SGLT-2i) (EMPA-REG OUTCOME with empagliflozin, CANVAS with canagliflozin and DECLARE with dapagliflozin) all revealed a robust and significant reduction in the hazard ratios of hospitalization for HF, from 27% to 35%, which remained consistent, significant and of similar magnitude regardless of the presence of a history of HF or established atherosclerotic cardiovascular disease. There is no association between reductions in HF risk and haemoglobin A1c (A1C) levels, while there is a significant association between reductions in HR for MACE and A1C levels (Spearman's correlation, r = 0.695; P = 0.013). All of the 12 CVOTs completed to date have provided reassurance of the overall cardiovascular safety of the newer anti-hyperglycaemic drugs. At present, the robust, consistent and reproducible reduction of approximately 30% in the risk of HF with SGLT-2i may be considered a class effect. The beneficial effect on MACE outcome observed with the use of some GLP-1RAs and SGLT-2i must be interpreted within the frame of the single trial.

Cardiovascular Actions and Clinical Outcomes With Glucagon-Like Peptide-1 Receptor Agonists and Dipeptidyl Peptidase-4 Inhibitors.

Potentiation of glucagon-like peptide-1 (GLP-1) action through selective GLP-1 receptor (GLP-1R) agonism or by prevention of enzymatic degradation by inhibition of dipeptidyl peptidase-4 (DPP-4) promotes glycemic reduction for the treatment of type 2 diabetes mellitus by glucose-dependent control of insulin and glucagon secretion. GLP-1R agonists also decelerate gastric emptying, reduce body weight by reduction of food intake and lower circulating lipoproteins, inflammation, and systolic blood pressure. Preclinical studies demonstrate that both GLP-1R agonists and DPP-4 inhibitors exhibit cardioprotective actions in animal models of myocardial ischemia and ventricular dysfunction through incompletely characterized mechanisms. The results of cardiovascular outcome trials in human subjects with type 2 diabetes mellitus and increased cardiovascular risk have demonstrated a cardiovascular benefit (significant reduction in time to first major adverse cardiovascular event) with the GLP-1R agonists liraglutide (LEADER trial [Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Ourcome Results], -13%) and semaglutide (SUSTAIN-6 trial [Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide], -24%). In contrast, cardiovascular outcome trials examining the safety of the shorter-acting GLP-1R agonist lixisenatide (ELIXA trial [Evaluation of Lixisenatide in Acute Coronary Syndrom]) and the DPP-4 inhibitors saxagliptin (SAVOR-TIMI 53 trial [Saxagliptin Assessment of Vascular Outcomes Recorded in Patients With Diabetes Mellitus-Thrombolysis in Myocardial Infarction 53]), alogliptin (EXAMINE trial [Examination of Cardiovascular Outcomes With Alogliptin Versus Standard of Care in Patients With Type 2 Diabetes Mellitus and Acute Coronary Syndrome]), and sitagliptin (TECOS [Trial Evaluating Cardiovascular Outcomes With Sitagliptin]) found that these agents neither increased nor decreased cardiovascular events. Here we review the cardiovascular actions of GLP-1R agonists and DPP-4 inhibitors, with a focus on the translation of mechanisms derived from preclinical studies to complementary findings in clinical studies. We highlight areas of uncertainty requiring more careful scrutiny in ongoing basic science and clinical studies. As newer more potent GLP-1R agonists and coagonists are being developed for the treatment of type 2 diabetes mellitus, obesity, and nonalcoholic steatohepatitis, the delineation of the potential mechanisms that underlie the cardiovascular benefit and safety of these agents have immediate relevance for the prevention and treatment of cardiovascular disease.

Incretin hormones: Their role in health and disease.

Incretin hormones are gut peptides that are secreted after nutrient intake and stimulate insulin secretion together with hyperglycaemia. GIP (glucose-dependent insulinotropic polypeptide) und GLP-1 (glucagon-like peptide-1) are the known incretin hormones from the upper (GIP, K cells) and lower (GLP-1, L cells) gut. Together, they are responsible for the incretin effect: a two- to three-fold higher insulin secretory response to oral as compared to intravenous glucose administration. In subjects with type 2 diabetes, this incretin effect is diminished or no longer present. This is the consequence of a substantially reduced effectiveness of GIP on the diabetic endocrine pancreas, and of the negligible physiological role of GLP-1 in mediating the incretin effect even in healthy subjects. However, the insulinotropic and glucagonostatic effects of GLP-1 are preserved in subjects with type 2 diabetes to the degree that pharmacological stimulation of GLP-1 receptors significantly reduces plasma glucose and improves glycaemic control. Thus, it has become a parent compound of incretin-based glucose-lowering medications (GLP-1 receptor agonists and inhibitors of dipeptidyl peptidase-4 or DPP-4). GLP-1, in addition, has multiple effects on various organ systems. Most relevant are a reduction in appetite and food intake, leading to weight loss in the long term. Since GLP-1 secretion from the gut seems to be impaired in obese subjects, this may even indicate a role in the pathophysiology of obesity. Along these lines, an increased secretion of GLP-1 induced by delivering nutrients to lower parts of the small intestines (rich in L cells) may be one factor (among others like peptide YY) explaining weight loss and improvements in glycaemic control after bariatric surgery (e.g., Roux-en-Y gastric bypass). GIP and GLP-1, originally characterized as incretin hormones, have additional effects in adipose cells, bone, and the cardiovascular system. Especially, the latter have received attention based on recent findings that GLP-1 receptor agonists such as liraglutide reduce cardiovascular events and prolong life in high-risk patients with type 2 diabetes. Thus, incretin hormones have an important role physiologically, namely they are involved in the pathophysiology of obesity and type 2 diabetes, and they have therapeutic potential that can be traced to well-characterized physiological effects.

Propensity-score-matched comparative analyses of simultaneously administered fixed-ratio insulin glargine 100 U and lixisenatide (iGlarLixi) vs sequential administration of insulin glargine and lixisenatide in uncontrolled type 2 diabetes.

AIM: To conduct two exploratory analyses to compare indirectly the efficacy and safety of simultaneous administration of insulin glargine 100 U (iGlar) and the glucagon-like peptide-1 receptor agonist (GLP-1RA) lixisenatide (Lixi) as a single-pen, titratable, fixed-ratio combination (iGlarLixi [LixiLan trials]) vs sequential administration of iGlar + Lixi (GetGoal Duo trials) in people with type 2 diabetes (T2D). MATERIALS AND METHODS: Propensity-score matching based on baseline covariates was used to compare simultaneous iGlarLixi vs sequential combination of iGlar + Lixi with the addition of Lixi in patients who did not reach the glycated haemoglobin (HbA1c) goal of <53 mmol/mol (<7%) after short-term use of iGlar alone (LixiLan-O vs GetGoal Duo-1 comparison) and vs sequential addition of Lixi in uncontrolled patients after long-term use of iGlar alone (LixiLan-L vs GetGoal Duo-2 comparison). RESULTS: In both analyses, compared with sequential iGlar + Lixi, iGlarLixi led to significantly greater HbA1c reductions with associated weight loss and significantly more patients reaching target HbA1c <53 mmol/mol despite lower insulin doses. Symptomatic hypoglycaemia rates were similar, despite greater HbA1c reductions with iGlarLixi. Lower rates of gastrointestinal adverse events were observed with iGlarLixi, probably as a result of the more gradual titration of Lixi with iGlarLixi. CONCLUSIONS: Indirect propensity-score-matched exploratory comparisons suggest that early treatment with a simultaneous, titratable, fixed-ratio combination of basal insulin and a GLP-1RA (iGlarLixi) may be more effective and possess better gastrointestinal tolerability than a sequential approach of adding a GLP-1RA in patients with uncontrolled T2D initiating or intensifying basal insulin therapy.

Impact of insulin glargine and lixisenatide on ß-cell function in patients with type 2 diabetes mellitus: A randomized open-label study.

It is known that ß-cell function can be enhanced by direct stimulation of insulin secretion or by induction of ß-cell rest, but whether both strategies can complement each other has not yet been examined. A total of 28 people with type 2 diabetes (glycated haemoglobin 7.8% ± 0.5%) were treated with either lixisenatide or titrated insulin glargine, followed by their combined administration, each over 4 weeks. First- and second-phase insulin secretion during an intravenous glucose challenge were calculated. First- and second-phase insulin secretion were not increased with glargine alone, but increased after addition of lixisenatide ( P < .001). Lixisenatide alone increased first- and second-phase insulin secretion ( P < .01). Addition of insulin glargine tended to further increase first-phase insulin secretion (P = .054), as well as insulin and C-peptide concentrations ( P < .05). Second-phase insulin secretion was not affected by the addition of glargine. The sequence of initiating lixisenatide or glargine had no effect on the final measures of glycaemia or insulin secretion. Thus, lixisenatide and, to a lesser extent, insulin glargine, increase glucose-stimulated insulin secretion in an additive manner.