Systematic review and meta-analysis of efficacy and safety of combinational therapy with metformin and dipeptidyl peptidase-4 inhibitors

Incretin and Pancreatic β-Cell Function in Patients with Type 2 Diabetes

To maintain normal glucose homeostasis after a meal, it is essential to secrete an adequate amount of insulin from pancreatic β-cells. However, if pancreatic β-cells solely depended on the blood glucose level for insulin secretion, a surge in blood glucose levels would be inevitable after the ingestion of a large amount of carbohydrates. To avoid a deluge of glucose in the bloodstream after a large carbohydrate- rich meal, enteroendocrine cells detect the amount of nutrient absorption from the gut lumen and secrete incretin hormones at scale. Since insulin secretion in response to incretin hormones occurs only in a hyperglycemic milieu, pancreatic β-cells can secrete a "Goldilocks" amount of insulin (i.e., not too much and not too little) to keep the blood glucose level in the normal range. In this regard, pancreatic β-cell sensitivity to glucose and incretin hormones is crucial for maintaining normal glucose homeostasis. In this Namgok lecture 2022, we review the effects of current anti-diabetic medications on pancreatic β-cell sensitivity to glucose and incretin hormones.

Neurological Manifestation of Incretin-Based Therapies in Patients with Type 2 Diabetes: A Systematic Review and Network Meta-Analysis

As a new class of antidiabetic drug, incretin-based therapies, which include dipeptidyl peptidase-4 inhibitors (DPP-4Is) and glucagon-like peptide-1 receptor agonists (GLP-1 RAs), have raised concerns about symptoms of withdrawal in patients with type 2 diabetes mellitus (T2DM), such as dizziness and headache. To systematically evaluate whether incretin-based therapies may lead to dizziness and headache in patients with T2DM compared to other traditional antidiabetic drugs or placebo. We searched Medline, Embase, the Cochrane library, and clinicaltrials.gov from inception through June 23, 2017, to identify randomized controlled trials of the safety of DPP-4Is or GLP-1 RAs versus placebo or other antidiabetic drugs in T2DM patients. We used the network meta-analysis under the frequentist framework to compare the association between multiple antidiabetic drugs and dizziness and headache. A total of 233 clinical trials with nine treatments and 147,710 patients were included: two incretin-based therapies, one placebo, and six traditional antidiabetic drugs (metformin, insulin, sulfonylurea, thiazolidinediones, alpha-glucosidase inhibitor, and sodium-glucose co-transporter 2). Compared to insulin, thiazolidinediones, or placebo, GLP-1 RAs statistically significantly increased the risk of dizziness (odds ratios [ORs]: 1.92, 1.57, and 1.40, respectively) and headache (ORs: 1.34, 1.41, and 1.18, respectively). DPP-4Is increased the risk of headache (OR: 1.22, 95% confidence interval [CI]: 1.02 to 1.46; moderate quality) and dizziness (OR: 1.46, 95% CI: 1.05 to 2.03; moderate quality) compared to insulin. Of the incretin-based therapies, DPP-4Is had a lower risk of dizziness than GLP-1 RAs (OR: 0.76, 95% CI: 0.67 to 0.87; high quality). Ranking probability analysis indicated that GLP-1 RAs may have the greatest risk of both dizziness and headache among the nine treatments (22.5% and 23.4%, respectively), whereas DPP-4Is were in the middle (46.2% and 45.0%, respectively). Incretin-based therapies increase the risk of dizziness and headache compared to insulin, thiazolidinediones, and placebo.

Efficacy and safety of evogliptin versus sitagliptin as an add-on therapy in Indian patients with type 2 diabetes mellitus inadequately controlled with metformin: A 24-week randomized, double-blind, non-inferiority, EVOLUTION INDIA study

AIM

This study aimed to assess efficacy and safety of evogliptin versus sitagliptin, when added to background metformin therapy in Indian patients with uncontrolled type 2 diabetes.

METHOD

Overall, 184 patients with uncontrolled type 2 diabetes (7% ≤ HbA_1c < 10%) receiving ≥8 weeks of stable metformin monotherapy (≥1 g/day), were randomized to receive add-on treatment (evogliptin 5 mg or sitagliptin 100 mg) for 24 weeks. Primary endpoint was change in HbA_1c from baseline to 12 weeks (non-inferiority margin: <0.35).

RESULTS

Mean reductions in HbA1c at 12 weeks in evogliptin- and sitagliptin-treated patients were -0.37 (1.06) and -0.32 (1.14), respectively. The adjusted mean difference between treatment groups was -0.022 (95% CI: -0.374, 0.330; P = 0.901), that demonstrated non-inferiority. Reductions in FPG and PPG were similar between evogliptin and sitagliptin at 12 and 24 weeks. Changes in body weight were comparable between the treatment groups. Patients achieving target HbA_1c < 7.0% (evogliptin, 26.7% vs. sitagliptin, 20%) was almost equal in both groups. Treatment-emergent adverse events occured in 52 patients (evogliptin, 25% and sitagliptin, 31.5%) and were generally mild.

CONCLUSIONS

Evogliptin was non-inferior to sitagliptin in HbA_1c reduction. It effectively improved glycemic control and was well tolerated in type 2 diabetes patients inadequately controlled by metformin alone.

Real-life safety and efficacy of vildagliptin as add-on to metformin in patients with type 2 diabetes in Turkey--GALATA study

OBJECTIVE

To evaluate tolerability/safety and the efficacy of the combination of vildagliptin plus metformin in a real-life population of patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

This multicenter, single-arm, 6 month, observational, prospective cohort study was conducted at 39 centers across Turkey. T2DM patients on vildagliptin and metformin for ≤4 weeks were enrolled regardless of their previous antidiabetic therapy.

MAIN OUTCOME MEASURES

Efficacy was evaluated by measuring hemoglobin A1c (HbA1c) levels. Tolerability/safety parameters evaluated included hypoglycemic events, gastrointestinal events, peripheral edema and weight gain.

RESULTS

This study enrolled 665 patients with a mean ± standard deviation (SD) age of 55.1 ± 10.2 years and female predominance (n = 394, 59.2%). Safety was assessed in all enrolled patients. Hypoglycemia was reported in 10 (1.5%) patients (95% confidence interval = 0.8-2.7%). Efficacy was assessed in 289 (43.5%) patients treated for 6 ± 1 months; these patients showed a mean decrease in HbA1c of 0.8% from baseline value of 7.8% (p < 0.001). The percentages of patients who achieved HbA1c targets of ≤6.5% and ≤7.0% were significantly increased, from 10.7% to 33.6% and from 22.1% to 52.6%, respectively (p < 0.001 each). The decrease in HbA1c was independent of baseline HbA1c (≤8% vs. 8-10% vs. ≥10%), age (≤65 vs. >65 years) and body mass index (<30 vs. ≥30 kg/m(2)) (p < 0.001 each). In total, 136 adverse events (AEs) were observed in 71 (10.7%) patients; 10 (1.5%) patients experienced hypoglycemia and gastrointestinal AEs were most commonly reported (n = 29, 4.4%).

CONCLUSIONS

In a 'real-life' setting, the vildagliptin and metformin combination was associated with significant improvements in reaching target HbA1c levels, even in elderly and obese patients with T2DM. Moreover, vildagliptin and metformin demonstrated a good overall tolerability/safety profile.