[Rationale supporting basal insulin-incretin combined therapies in type 2 diabetes]

Type 2 diabetes is characterized by an insulin secretory defect that cannot compensate for insulin resistance. Such relative defect is present in the fasting state (insufficient basal insulin levels) and contributes to overnight hyperglycaemia; it is even more pronounced in the postprandial state when it is then the main responsible factor for hyperglycaemia following meals. An original approach to correct these two disturbances is to propose a therapy combining the injection of a basal insulin (most commonly at bedtime to better control fasting glycaemia) and the administration of an incretin-based medication to potentiate insulin response to the three main meals, without inducing hypoglycaemia. This latter effect can be obtained either by blocking the degradation of incretin hormones with an oral inhibitor of dipeptidyl peptidase-4 (gliptin), or by injecting an agonist of glucagon-like peptide-1 (GLP-1) receptors. These basal insulin-incretin combined therapies are well validated in various controlled trials and observational studies. Lixisenatide is the first GLP-1 receptor agonist being reimbursed in this specific indication of combination with basal insulin in Belgium.