Genetic determinants predicting efficacy of glucose-lowering drugs?: a long way to go

A genetic variant in GLP1R is associated with response to DPP-4 inhibitors in patients with type 2 diabetes

Incretin hormone-based therapy in type 2 diabetes has been widely used, and dipepdityl peptidase-4 (DPP-4) inhibitors, which prevent incretin degradation, have become popular oral hypoglycemic agents. The efficacy of DPP-4 inhibitors varies from individuals, and factors determining responses to DPP-4 inhibitors have not been fully established. We aimed to investigate whether genetic variations in glucagon-like peptide (GLP-1) receptor are associated with responses to DPP-4 inhibitors in patients with type 2 diabetes.Genetic variations of rs3765467 in GLP-1 receptor were explored in 246 patients with type 2 diabetes who received DPP-4 inhibitors treatment for 24 weeks in addition to previous medication. Patients with glycated hemoglobin (HbA1c) > 7% and who were naive to any DPP-4 inhibitors were enrolled. Responders were defined as those who showed a > 10% reduction in HbA1c after DPP-4 inhibitor treatment.DPP-4 inhibitors improved glycemic parameters and lipid profiles. Compared to the major genotype (GG), a larger proportion of patients with the minor allele genotype (GA/AA) were responders (P = 0.018), and also showing greater HbA1c reductions (1.3 ± 1.1 vs 0.9 ± 1.2%; P = 0.022). This genetic effect remained significant even after adjustment for other confounding factors (OR = 2.00, 95% CI = 1.03-3.89).Polymorphism in the GLP-1 receptor may influence DPP-4 inhibitor response. Further studies in larger population will help determine the association between genetic variation and interindividual differences in DPP-4 inhibitor therapy.

Pharmacogenetic aspects of the treatment of Type 2 diabetes with the incretin effect enhancers

Incretin effect enhancers are drugs used in the treatment of Type 2 diabetes and include GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors (gliptins). Variants in several genes were shown to be involved in the physiology of incretin secretion. Only two gene variants have evidence also from pharmacogenetic studies. TCF7L2 rs7903146 C>T and CTRB1/2 rs7202877 T>G minor allele carriers were both associated with a smaller reduction in HbA1c after gliptin treatment when compared with major allele carriers. After replication in further studies, these observations could be of clinical significance in helping to identify patients with potentially lower or higher response to gliptin treatment.

Current issues in GLP-1 receptor agonist therapy for type 2 diabetes

The clinical management of hyperglycemia in patients with type 2 diabetes mellitus (T2DM) is guided not only by published treatment algorithms, but also by consideration of recent evidence and through consultation with colleagues and experts. Recent studies have dramatically increased the amount of information regarding the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs). Topics that may be of particular interest to clinicians who treat T2DM patients include relative glycemic control efficacy of GLP-1 RAs, use of GLP-1 RAs across T2DM progression and in combination with insulin, recent data regarding GLP-1 RA safety, nonglycemic actions of GLP-1 RAs, including weight effects, and impact of GLP-1 RAs on patient quality of life and treatment satisfaction. The following review includes expert consideration of these topics with emphasis on recent, relevant reports to illustrate current perspectives.