Sitagliptin is effective and safe as add-on to insulin in patients with absolute insulin deficiency: a case series

<p>Abstract</p> <p>Introduction</p> <p>It is generally believed that incretin-based therapies are effective in patients possessing certain levels of preserved β-cell function. So far, there are no reports that show the effectiveness of dipeptidyl peptidase-4 inhibitors in patients who absolutely lack the capacity for endogenous insulin secretion.</p> <p>Case presentation</p> <p>This report describes the efficacy of sitagliptin in three Japanese patients (a 91-year-old Japanese woman with type 1 diabetes, a 54-year-old Japanese man with type 2 diabetes and a 30-year-old Japanese man with features of both type 1 and type 2 diabetes) who had no detectable post-meal C-peptide levels. Although they were receiving intensive insulin therapy together with some oral hypoglycemic agents, their glycemic control remained poor. Sitagliptin was added to the ongoing therapeutic regimen to provide better glycemic control. Although these patients had mild hypoglycemia, effective reductions of hemoglobin A1c levels were observed without any adverse events in the liver and kidney during the following 24 weeks. Two of the patients were able to reduce their insulin doses, and one of the patients could discontinue one of the oral hypoglycemic agents. There was no weight gain or gastrointestinal complaints among the three patients. Post-meal C-peptide levels remained undetectable after sitagliptin treatment.</p> <p>Conclusion</p> <p>This report demonstrates that sitagliptin is effective and safe as an add-on therapy to insulin in reducing blood glucose levels in patients who absolutely lack the capacity for endogenous insulin secretion. The improvement seen in glycemic control could not be due to enhanced endogenous insulin secretion, since post-meal C-peptide levels remained undetectable after sitagliptin treatment, but it could be a result of other factors (for example, suppression of glucagon levels). However, the glucagon-suppressive effect of sitagliptin is known to be rather weak and short-lived. Given this background, a novel hypothesis that the glycemic effects of this drug may be caused by mechanisms that are independent of the glucagon-like peptide 1 axis (extra-pancreatic effect) will be discussed.</p

Antidiabetic Actions of Endogenous and Exogenous GLP-1 in Type 1 Diabetic Patients With and Without Residual β-Cell Function

OBJECTIVE—To investigate the effect of exogenous as well as endogenous glucagon-like peptide 1 (GLP-1) on postprandial glucose excursions and to characterize the secretion of incretin hormones in type 1 diabetic patients with and without residual b-cell function. RESEARCH DESIGN AND METHODS—Eight type 1 diabetic patients with (T1D+), eight without (T1D2) residual b-cell func-tion, and eight healthy matched control subjects were studied during a mixed meal with concomitant infusion of GLP-1 (1.2 pmol/kg/min), saline, or exendin 9-39 (300 pmol/kg/min). Before the meal, half dose of usual fast-acting insulin was injected. Plasma glucose (PG), glucagon, C-peptide, total GLP-1, intact glucose-dependent insulinotropic polypeptide (GIP), free fatty acids, triglycerides, and gastric emptying rate (GE) by plasma acetaminophen were measured

Pharmacokinetic Properties of Liraglutide as Adjunct to Insulin in Subjects with Type 1 Diabetes Mellitus.

BACKGROUND: The pharmacokinetic properties of liraglutide, a glucagon-like peptide-1 receptor agonist approved for the treatment of type 2 diabetes mellitus (T2D), have been established in healthy individuals and subjects with T2D. Liraglutide has been under investigation as adjunct treatment to insulin in type 1 diabetes mellitus (T1D). This single-center, double-blind, placebo-controlled, crossover, clinical pharmacology trial is the first to analyze the pharmacokinetic properties of liraglutide as add-on to insulin in T1D. METHODS: Subjects (18-64 years; body mass index 20.0-28.0 kg/m(2); glycated hemoglobin ≤9.5 %) were randomized 1:1:1 to 0.6, 1.2, or 1.8 mg liraglutide/placebo. Each group underwent two 4-week treatment periods (liraglutide then placebo or placebo then liraglutide) separated by a 2- to 3-week washout. Both trial drugs were administered subcutaneously, once daily, as adjunct to insulin. A stepwise hypoglycemic clamp was performed at the end of each treatment period (data reported previously). Pharmacokinetic endpoints were derived from liraglutide concentration-time curves after the final dose and exposure was compared with data from previous trials in healthy volunteers and subjects with T2D. RESULTS: The pharmacokinetic properties of liraglutide in T1D were comparable with those observed in healthy volunteers and subjects with T2D. Area under the steady-state concentration-time curve (AUC) and maximum plasma concentration data were consistent with dose proportionality of liraglutide. Comparison of dose-normalized liraglutide AUC suggested that exposure in T1D, when administered with insulin, is comparable with that observed in T2D. CONCLUSIONS: Liraglutide, administered as adjunct to insulin in subjects with T1D, shows comparable pharmacokinetics to those in subjects with T2D. ClinicalTrials.gov Identifier: NCT01536665

Beneficial effects of parenteral GLP-1 delivery by cell therapy in insulin-deficient streptozotocin diabetic mice.

Parenteral delivery of long-Acting glucagon-like peptide-1 (GLP-1) mimetics has received much attention as a therapeutic option for diabetes. However, cell therapy-based GLP-1 treatments may provide a more physiological regulation of blood glucose. The present study assessed the effects of chronic GLP-1 delivery by cell therapy, using the GLP-1-secreting GLUTag cell line, in normoglycemic and streptozotocin-induced diabetic mice. GLUTag cell aggregates were transplanted into the subscapular region of mice. Over 30 days, cellular transplantation gave rise to encapsulated and well-vascularized growths, which contained immunoreactive GLP-1. Cell implantation was well tolerated and had no appreciable metabolic effects in normal mice. However, transplantation significantly (P<0.001) countered excessive food and fluid intake in diabetic mice and maintained normal body weight. Circulating glucose (P<0.01) and glucagon (P<0.05) were significantly reduced and plasma insulin and GLP-1 dramatically increased. This was associated with significantly (P<0.01) improved glucose tolerance in diabetic mice. Histological examination of the pancreata of these mice revealed elevations (P<0.001) in islet and β-cell area, with reduced (P<0.001) -cell area. Increased β-cell mass reflected the enhanced proliferation relative to apoptosis. These studies emphasize the potential of chronic GLP-1 delivery by cell therapy as a potential therapeutic option for diabetes