Randomized, double-blind, placebo-controlled dose-finding study of the dipeptidyl peptidase-4 inhibitor linagliptin in pediatric patients with type 2 diabetes.

OBJECTIVE: To identify the dose of the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin in pediatric patients with type 2 diabetes (T2D). METHODS: Double-blind, randomized, controlled parallel group study comparing linagliptin 1 and 5 mg once daily, with placebo in 39 patients with T2D aged 10 to below 18 years. The primary efficacy endpoint was the change from baseline in glycated hemoglobin (HbA1c) after 12 weeks of treatment. The key pharmacodynamic endpoint was DPP-4 inhibition during steady-state. RESULTS: Compared to placebo, there was a dose-dependent reduction in mean HbA1c of 0.48% and 0.63% with linagliptin 1 and 5 mg, respectively, associated with corresponding declines in mean fasting plasma glucose (FPG) of 5.6 and 34.2 mg/dL. Median DPP-4 inhibition was 38% with linagliptin 1 mg and 79% with linagliptin 5 mg. Geometric mean trough levels of linagliptin were 3.80 and 7.42 nmol/L in the 1 and 5 mg groups, respectively; levels that were slightly higher than in adult patients with T2D that were most likely caused by higher plasma DPP-4 concentrations in the study population. There were no drug-related adverse events during treatment with either dose of linagliptin. CONCLUSIONS: Linagliptin was well tolerated and induced dose-dependent DPP-4 inhibition that was accompanied by corresponding reductions in HbA1c and FPG levels in young people with T2D. The results are consistent with the clinical efficacy and safety profile that have been reported for linagliptin in adult patients with T2D, favoring linagliptin 5 mg over 1 mg.

Evaluation of 1,5-anhydroglucitol, hemoglobin A1c, and glucose levels in youth and young adults with type 1 diabetes and healthy controls.

BACKGROUND AND OBJECTIVE: Serum 1,5-anhydroglucitol (1,5-AG) is a marker of hyperglycemic excursions in adults with diabetes and hemoglobin A1c (HbA1c) < 8%. We compared 1,5-AG levels among youth and young adults with and without type 1 diabetes (T1D) and investigated the utility of 1,5-AG in the assessment of glycemic status in pediatric T1D. METHODS: We compared 1,5-AG, HbA1c, and plasma glucose levels in 138 patients with T1D (duration ≥1 yr) and 136 healthy controls, aged 10-30 yr. Within each group, we investigated associations between 1,5-AG and clinical characteristics, HbA1c and random plasma glucose. For patients with T1D, 1,5-AG was further analyzed according to HbA1c strata: <8, 8-9, and >9%. RESULTS: Compared to controls, patients with T1D had higher HbA1c (8.5 ± 1.6 vs. 5.1 ± 0.4%, p < 0.0001), lower 1,5-AG (4.0 ± 2.0 vs. 24.7 ± 6.4 µg/mL, p < 0.0001), and higher glucose (11.1 ± 5.2 vs. 5.1 ± 0.9 mmol/L, p < 0.0001). Males had higher 1,5-AG than females within patients (4.5 ± 2.3 vs. 3.4 ± 1.6 µg/mL, p = 0.003) and controls (26.0 ± 6.6 vs. 23.5 ± 6.0 µg/mL, p = 0.02). 1,5-AG was not correlated with glucose in either group. 1,5-AG was significantly correlated to HbA1c in patients, but not controls. For patients with HbA1c < 8%, 1,5-AG demonstrated the widest range and was not predicted by HbA1c; 1,5-AG levels were narrowly distributed among patients with HbA1c ≥ 8%. CONCLUSIONS: Youth and young adults with T1D demonstrate similar 1,5-AG levels which are distinct from controls. 1,5-AG assessment may provide unique information beyond that provided by HbA1c in the mid-term assessment of glycemic control in young patients with T1D and HbA1c < 8%.

Renin release in response to Renin system blockade: activation of the Renin system in type 1 diabetes mellitus.

Activation of the renin-angiotensin system (RAS) in diabetes is thought to contribute to nephropathy. This is suggested by findings of an enhanced renovascular (RPF) response to RAS blockade with angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs). An alternative approach to assess RAS activation is the evaluation of renin release following RAS blockade. Forty-four consecutively enrolled Type 1 diabetic patients (28.2+/-1.5 years) and 37 normal subjects (37+/-2.6 years) in high salt balance were given 25 mg of captopril and 16 mg of candesartan p.o. on consecutive days. All subjects were Caucasian. All, except one diabetic patient, had normal renal function. Plasma renin activity (PRA) and renal plasma flow (RPF) were measured for four hours after both drugs, and at eight, and 24 hours after candesartan. As anticipated, both drugs increased PRA. Peak responses (90' after captopril) were 5.6+/-1 ng/mL Ang I/hour in diabetic patients, and 1.7+/-0.9 ng/mL Ang I/hour in normal subjects (p<0.001). Responses to both drugs were correlated in diabetic patients for PRA (r=0.623; p=0.001) and for RPF (r=0.9; p<0.001). When the PRA response to captopril was below the median, the RPF response was limited (22.1+/-17.6 ml/minute/1.73 m2). When it was above the median, the RPF response was also larger (62.2+/-13.9 ml/minute/1.73 m2; p=0.006). Renin response to ACE-I and ARB confirms activation of the RAS in diabetic patients.