Linagliptin treatment in subjects with type 2 diabetes with and without mild-to-moderate renal impairment

AIMS

Renal disease is a frequent comorbidity of type 2 diabetes mellitus (T2DM) and an important factor complicating the choice of glucose-lowering drugs. The aim of this analysis was to evaluate the efficacy and safety of the dipeptidyl peptidase (DPP)-4 inhibitor linagliptin (5 mg/day) in mono, dual or triple oral glucose-lowering regimens in subjects with T2DM and mild or moderate renal impairment (RI).

METHODS

In this pooled analysis of three 24-week, placebo-controlled, phase 3 trials, subjects with mild (estimated glomerular filtration rate (eGFR) 60-<90 ml/min/1.73 m(2) , n = 838) or moderate RI (30-<60 ml/min/1.73 m(2), n = 93) were compared with subjects with normal renal function (≥90 ml/min/1.73 m(2), n = 1212).

RESULTS

Subjects with RI were older, had longer duration of diabetes, and increased prevalence of diabetes-related comorbidities. After 24 weeks, linagliptin achieved consistent placebo-corrected mean glycated haemoglobin (HbA1c) changes across the three renal function categories: normal (-0.63%; p < 0.0001), mild RI (-0.67%; p < 0.0001) and moderate RI (-0.53%; p < 0.01), with no inter-group difference (p = 0.74). Renal function with linagliptin remained stable across all categories. In linagliptin-treated subjects, overall adverse event (AE) rates and serious AE rates were similar to placebo. The incidence of hypoglycaemia with linagliptin and placebo was 11.1 versus 6.9%, 11.9 versus 9.0% and 15.9 versus 12.0% in the normal, mild RI and moderate RI categories, respectively.

CONCLUSIONS

This pooled analysis provides evidence that linagliptin is an effective, well-tolerated and convenient treatment in subjects with T2DM and mild or moderate RI.

Efficacy and safety of vildagliptin in patients with type 2 diabetes mellitus inadequately controlled with dual combination of metformin and sulphonylurea

AIM

The broadly used combination of metformin and sulphonylurea (SU) often fails to bring patients to glycaemic goal. This study assessed the efficacy and safety of vildagliptin as add-on therapy to metformin plus glimepiride combination in patients with type 2 diabetes mellitus (T2DM) who had inadequate glycaemic control.

METHODS

A multicentre, double-blind, placebo-controlled study randomized patients to receive treatment with vildagliptin 50 mg bid (n = 158) or placebo (n = 160) for 24 weeks.

RESULTS

After 24 weeks, the adjusted mean change in haemoglobin A1c (HbA1c) was -1.01% with vildagliptin (baseline 8.75%) and -0.25% with placebo (baseline 8.80%), with a between-treatment difference of -0.76% (p < 0.001). Significantly more patients on vildagliptin achieved the HbA1c target <7% (28.3% vs. 5.6%; p < 0.001). The difference in fasting plasma glucose reduction between vildagliptin and placebo was -1.13 mmol/l (p < 0.001). In subgroup of patients with baseline HbA1c ≤8%, vildagliptin reduced HbA1c by 0.74% from baseline 7.82% (between-treatment difference: -0.97%; p < 0.001) with significantly more patients achieving the HbA1c target <7% (38.6% vs. 13.9%; p = 0.014). Vildagliptin was well tolerated with low incidence of hypoglycaemia, slightly higher than with placebo (5.1% vs. 1.9%) and no clinically relevant weight gain.

CONCLUSIONS

Vildagliptin significantly improved glycaemic control in patients with T2DM inadequately controlled with metformin plus glimepiride combination. The addition of vildagliptin was well tolerated with low risk of hypoglycaemia and weight gain. This makes vildagliptin an attractive treatment option for patients failing on metformin plus SU particularly in patients with baseline HbA1c ≤8%.

Effect of insulin degludec versus sitagliptin in patients with type 2 diabetes uncontrolled on oral antidiabetic agents

AIM

The efficacy and safety of insulin degludec (IDeg), a new basal insulin with an ultra-long duration of action, was compared to sitagliptin (Sita) in a 26-week, open-label trial.

METHODS

Insulin-naïve subjects with type 2 diabetes [n = 458, age: 56 years, diabetes duration: 7.7 years, glycosylated haemoglobin (HbA1c): 8.9% (74 mmol/mol)] were randomized (1 : 1) to once-daily IDeg or Sita (100 mg orally) as add-on to stable treatment with 1 or 2 oral antidiabetic drugs (OADs).

RESULTS

Superiority of IDeg to Sita in improving HbA1c and fasting plasma glucose (FPG) was confirmed [estimated treatment difference (ETD) IDeg-Sita for HbA1c: -0.43%-points [95% confidence interval (CI): -0.61; -0.24, p < 0.0001] and for FPG: -2.17 mmol/l (95% CI: -2.59; -1.74, p < 0.0001)]. HbA1c < 7% (<53 mmol/mol) was achieved by 41% (IDeg) versus 28% (Sita) of patients, estimated odds ratio IDeg/Sita: 1.60 (95% CI: 1.04; 2.47, p = 0.034). There was no statistically significant difference in the rate of nocturnal confirmed hypoglycaemia between IDeg and Sita [0.52 vs. 0.30 episodes/patient-year, estimated rate ratio (ERR): IDeg/Sita: 1.93 (95% CI: 0.90; 4.10, p = 0.09)]. Rates of overall confirmed hypoglycaemia were higher with IDeg than with Sita [3.1 vs. 1.3 episodes/patient-year, ERR IDeg/Sita: 3.81 (95% CI: 2.40; 6.05, p < 0.0001)]. IDeg was associated with a greater change in body weight than Sita [ETD IDeg-Sita: 2.75 kg (95% CI: 1.97; 3.54, p < 0.0001)]. The overall rates of adverse events were low and similar for both groups.

CONCLUSIONS

In patients unable to achieve good glycaemic control on OAD(s), treatment intensification with IDeg offers an effective, well-tolerated alternative to the addition of a second or third OAD.

PPARG2 Pro12Ala and ADAMTS9 rs4607103 as "insulin resistance loci" and "insulin secretion loci" in Italian individuals. The GENFIEV study and the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 4

We investigated cross-sectionally whether the type 2 diabetes (T2DM) risk alleles of rs1801282 (PPARG2) and rs4607103 (ADAMTS9) were associated with T2DM and/or insulin sensitivity (IS) and beta cell function (βF) in Italians without and with newly diagnosed T2DM. In 676 nondiabetic subjects (336 NGR and 340 IGR) from the GENFIEV study and in 597 patients from the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS), we (1) genotyped rs1801282 and rs4607103, (2) assessed βF by C-peptide/glucose modeling after OGTT, and (3) assessed IS by HOMA-IR in both studies and by euglycemic insulin clamp in VNDS only. Logistic, linear, and two-stage least squares regression analyses were used to test (a) genetic associations with T2DM and with pathophysiological phenotypes, (b) causal relationships of the latter ones with T2DM by a Mendelian randomization design. Both SNPs were associated with T2DM. The rs4607103 risk allele was associated to impaired βF (p < 0.01) in the GENFIEV study and in both cohorts combined. The rs1801282 genotype was associated with IS both in the GENFIEV study (p < 0.03) and in the VNDS (p < 0.03), whereas rs4607103 did so in the VNDS only (p = 0.01). In a Mendelian randomization design, both HOMA-IR (instrumental variables: rs1801282, rs4607103) and βF (instrumental variable: rs4607103) were related to T2DM (p < 0.03-0.01 and p < 0.03, respectively). PPARG2 and ADAMTS9 variants are both associated with T2DM and with insulin resistance, whereas only ADAMTS9 may be related to βF. Thus, at least in Italians, they may be considered bona fide "insulin resistance genes".

Hypoglycaemia risk with insulin degludec compared with insulin glargine in type 2 and type 1 diabetes: a pre-planned meta-analysis of phase 3 trials

AIM

Hypoglycaemia and the fear of hypoglycaemia are barriers to achieving normoglycaemia with insulin. Insulin degludec (IDeg) has an ultra-long and stable glucose-lowering effect, with low day-to-day variability. This pre-planned meta-analysis aimed to demonstrate the superiority of IDeg over insulin glargine (IGlar) in terms of fewer hypoglycaemic episodes at equivalent HbA1c in type 2 and type 1 diabetes mellitus (T2DM/T1DM).

METHODS

Pooled patient-level data for self-reported hypoglycaemia from all seven (five in T2DM and two in T1DM) randomized, controlled, phase 3a, treat-to-target trials in the IDeg clinical development programme comparing IDeg once-daily (OD) vs. IGlar OD were analysed.

RESULTS

Four thousand three hundred and thirty subjects (2899 IDeg OD vs. 1431 IGlar OD) were analysed. Among insulin-naïve T2DM subjects, significantly lower rates of overall confirmed, nocturnal confirmed and severe hypoglycaemic episodes were reported with IDeg vs. IGlar: estimated rate ratio (RR):0.83[0.70;0.98](95%) (CI) , RR:0.64[0.48;0.86](95%) (CI) and RR:0.14[0.03;0.70](95%) (CI) . In the overall T2DM population, significantly lower rates of overall confirmed and nocturnal confirmed episodes were reported with IDeg vs. IGlar [RR:0.83[0.74;0.94](95%) (CI) and RR:0.68[0.57;0.82](95%) (CI) ). In the T1DM population, the rate of nocturnal confirmed episodes was significantly lower with IDeg vs. IGlar during maintenance treatment (RR:0.75[0.60;0.94](95%) (CI) ). Reduction in hypoglycaemia with IDeg vs. IGlar was more pronounced during maintenance treatment in all populations.

CONCLUSIONS

The limitations of this study include the open-label design and exclusion of subjects with recurrent severe hypoglycaemia. This meta-analysis confirms that similar improvements in HbA1c can be achieved with fewer hypoglycaemic episodes, particularly nocturnal episodes, with IDeg vs. IGlar across a broad spectrum of patients with diabetes.

Pituitary autoimmunity in patients with diabetes mellitus and other endocrine disorders

OBJECTIVE

Pituitary autoimmunity is often found in association with other endocrine autoimmune or non-autoimmune diseases. Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) in patients with Type 1 diabetes mellitus (T1DM) or Type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

In this casecontrol study 111 patients with T1DM, 110 patients with T2DM, and 214 healthy controls were enrolled in a tertiary referral center. Pituitary, thyroperoxidase, thyroglobulin, 21-hydroxylase, and parietal cell antibodies were assessed in all cases. Endocrine function was further assessed by basal hormone measurement and by dynamic tests, as well as a pituitary magnetic resonance imaging (MRI) was performed in those patients found positive for PitAb.

RESULTS

PitAb prevalence was higher in T1DM (4 out of 111, 3.6%) than in T2DM (0 out of 110, p=0.045) and in healthy subjects (1 out of 214, 0.5% p=0.029). Prevalence of other autoimmune diseases was significantly higher in patients with T1DM (45 out of 111, 40.5%) when compared with patients with T2DM (18 out of 110 T2DM, 16.3%, p<0.001). Patients with T1DM and PitAb positivity were found with a pituitary lesion at MRI in 2 cases and pituitary dysfunction in one case.

CONCLUSIONS

A significant association between pituitary autoimmunity and T1DM was found, in particular in subjects with one or more other endocrine autoimmune diseases.

Addition of either pioglitazone or a sulfonylurea in type 2 diabetic patients inadequately controlled with metformin alone: impact on cardiovascular events. A randomized controlled trial

BACKGROUND AND AIMS

Metformin is the first-line therapy in type 2 diabetes. In patients inadequately controlled with metformin, the addition of a sulfonylurea or pioglitazone are equally plausible options to improve glycemic control. However, these drugs have profound differences in their mechanism of action, side effects, and impact on cardiovascular risk factors. A formal comparison of these two therapies in terms of cardiovascular morbidity and mortality is lacking. The TOSCA.IT study was designed to explore the effects of adding pioglitazone or a sulfonylurea on cardiovascular events in type 2 diabetic patients inadequately controlled with metformin.

METHODS

Multicentre, randomized, open label, parallel group trial of 48 month duration. Type 2 diabetic subjects, 50-75 years, BMI 20-45 Kg/m(2), on secondary failure to metformin monotherapy will be randomized to add-on a sulfonylurea or pioglitazone. The primary efficacy outcome is a composite endpoint of all-cause mortality, nonfatal myocardial infarction, nonfatal stroke, and unplanned coronary revascularization. Principal secondary outcome is a composite ischemic endpoint of sudden death, fatal and non-fatal myocardial infarction and stroke, endovascular or surgical intervention on the coronary, leg or carotid arteries, major amputations. Side effects, quality of life and economic costs will also be evaluated. Efficacy, safety, tolerability, and study conduct will be monitored by an independent Data Safety Monitoring Board. End points will be adjudicated by an independent external committee.

CONCLUSIONS

TOSCA.IT is the first on-going study investigating the head-to-head comparison of adding a sulfonylurea or pioglitazone to existing metformin treatment in terms of hard cardiovascular outcomes.

REGISTRATION

Clinicaltrials.gov ID NCT00700856.

Long-term safety and efficacy of linagliptin as monotherapy or in combination with other oral glucose-lowering agents in 2121 subjects with type 2 diabetes: up to 2 years exposure in 24-week phase III trials followed by a 78-week open-label extension

Aim:  The aim of this study was to evaluate the long-term safety, tolerability and efficacy of the dipeptidyl peptidase-4 inhibitor linagliptin given either alone or in combination with other oral glucose-lowering agents in persons with type 2 diabetes. Methods:  A 78-week open-label extension study evaluated subjects who participated in one of four preceding 24-week, randomised, double-blind, placebo-controlled parent trials and who received linagliptin, linagliptin + metformin, linagliptin + metformin + a sulphonylurea or linagliptin + pioglitazone (all with linagliptin administered orally once daily). Individuals receiving one of these treatments during a previous trial continued the same treatment (n = 1532) for up to a total of 102 weeks, whereas those previously receiving placebo were switched to linagliptin (n = 589). All 2121 participants received at least one dose of the trial medication and were included in the primary safety analysis. Results:  In subjects previously receiving active treatment, the glycosylated haemoglobin A(1c) reduction achieved during the 24-week parent trials was sustained through the 78-week extension period (change from baseline to week 102: -0.8%). Drug-related adverse events were experienced by 14.3% of participants. Hypoglycaemia occurred in 13.9% of participants and was similar between those previously receiving treatment (13.6%) and those switching from placebo to linagliptin (14.6%). Hypoglycaemia occurred most frequently with the use of metformin + a sulphonylurea background therapy (11%). Overall, no clinically relevant changes in body weight were observed. Conclusion:  Long-term treatment with linagliptin was well tolerated with no change in the safety profile observed during the extension study. Sustained long-term glycaemic control was maintained for up to 102 weeks with either linagliptin monotherapy or linagliptin in combination with other oral glucose-lowering agents.

Evidence for a role of frataxin in pancreatic islets isolated from multi-organ donors with and without type 2 diabetes mellitus

Frataxin (FXN) is a mitochondrial protein involved in iron metabolism and in the modulation of reactive oxygen and/or nitrogen species production. No information is currently available as for the role of frataxin in isolated human pancreatic islets. We studied islets from pancreases of multi-organ donors with (T2DM) and without (Ctrl) Type 2 diabetes mellitus. In these islets, we determined FXN gene and protein expression by qualitative and quantitative Real-Time RT-PCR, nitrotyrosine concentration, and insulin release in response to glucose stimulation (SI). FXN gene and protein were expressed in human islets, though the level of expression was much lower in T2DM islets. The latter also had lower insulin release and higher concentration of nitrotyrosine. A positive correlation was apparent between SI and FXN gene expression, while a negative correlation was found between nitrotyrosine islet concentration and FXN expression. Transfection of Ctrl islets with siRNA FXN caused reduction of FXN expression, increase of nitrotyrosine concentration, and reduction of insulin release. In conclusion, in human pancreatic islets FXN contributes to regulation of oxidative stress and insulin release in response to glucose. In islets from T2DM patients FXN expression is reduced while oxidative stress is increased and insulin release in response to glucose impaired.

Type 2 diabetes mellitus worsens arterial stiffness in hypertensive patients through endothelial dysfunction

AIMS/HYPOTHESIS

Endothelium-derived factors are thought to be physiological modulators of large artery stiffness. The aim of the study was to investigate whether endothelial function could be a determinant of arterial stiffness in essential hypertensive patients, in relation with the concomitant presence of type 2 diabetes mellitus.

METHODS

The study included 341 participants (84 hypertensive patients with and 175 without type 2 diabetes mellitus, 82 matched controls). Brachial artery endothelium-dependent flow-mediated dilation (FMD) was determined by high-resolution ultrasound and computerised edge detection system. Applanation tonometry was used to measure carotid-femoral pulse wave velocity (PWV).

RESULTS

Hypertensive patients with diabetes had higher PWV (10.1 ± 2.3 m/s vs 8.6 ± 1.4 m/s, p < 0.001) and lower FMD (3.51 ± 2.07 vs 5.16 ± 2.96%, p < 0.001) than non-diabetic hypertensive patients, who showed impaired vascular function when compared with healthy participants (7.9 ± 1.6 m/s and 6.68 ± 3.67%). FMD was significantly and negatively correlated to PWV only in hypertensive diabetic patients (r = -0.456, p < 0.001), but not in hypertensive normoglycaemic patients (r = -0.088, p = 0.248) or in healthy participants (r = 0.008, p = 0.946). Multivariate analysis demonstrated that, in the diabetic group, FMD remained an independent predictor of PWV after adjustment for confounders (r(2) = 0.083, p = 0.003). Subgroup analysis performed in non-diabetic hypertensive patients revealed that neither obesity nor the metabolic syndrome affected the relationship between FMD and PWV.

CONCLUSIONS/INTERPRETATION

Endothelial dysfunction is a determinant of aortic stiffness in hypertensive diabetic patients but not in hypertensive patients without diabetes. These results suggest that type 2 diabetes mellitus on top of hypertension might worsen arterial compliance by endothelium-related mechanisms.