Pharmacokinetics of Faster and Standard Insulin Aspart During Fully Closed-Loop Insulin Delivery in Type 2 Diabetes

Improvements in Glycemic Control Achieved by Altering the tmax Setting in the iLet® Bionic Pancreas When Using Fast-Acting Insulin Aspart: A Randomized Trial

INTRODUCTION

We investigated the safety of, and glucose control by, the insulin-only configuration of the iLet^® bionic pancreas delivering fast-acting insulin aspart (faster aspart), using the same insulin-dosing algorithm but different time to maximal serum drug concentration (t_max) settings, in adults with type 1 diabetes.

METHODS

We performed a single-center, single-blinded, crossover (two 7-day treatment periods) escalation trial over three sequential cohorts. Participants from each cohort were randomized to a default t_max setting (t₆₅ [t_max = 65 min]) followed by a non-default t_max setting (t₅₀ [t_max = 50 min; cohort 1], t₄₀ [t_max = 40 min; cohort 2], t₃₀ [t_max = 30 min; cohort 3]), or vice versa, all with faster aspart. Each cohort randomized eight new participants if escalation-stopping criteria were not met in the previous cohort.

RESULTS

Overall, 24 participants were randomized into three cohorts. Two participants discontinued treatment, one due to reported 'low blood glucose' during the first treatment period of cohort 3 (t₃₀). Mean time in low sensor glucose (< 54 mg/dl, primary endpoint) was < 1.0% for all t_max settings. Mean sensor glucose in cohorts 1 and 2 was significantly lower at non-default versus default t_max settings, with comparable insulin dosing. The mean time sensor glucose was in range (70-180 mg/dl) was > 70% for all cohorts, except the default t_max setting in cohort 1. No severe hypoglycemic episodes were reported. Furthermore, there were no clinically significant differences in adverse events between the groups.

CONCLUSION

There were no safety concerns with faster aspart in the iLet at non-default t_max settings. Improvements were observed in mean sensor glucose without increases in low sensor glucose at non-default t_max settings.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03816761.

Effect of nutrition on postprandial glucose control in hospitalized patients with type 2 diabetes receiving fully automated closed-loop insulin therapy

Fully automated closed-loop insulin delivery may offer a novel way to manage diabetes in hospital. However, postprandial glycaemic control remains challenging. We aimed to assess the effect of nutritional intake on postprandial glucose control in hospitalized patients with type 2 diabetes receiving fully closed-loop insulin therapy. The effects of different meal types and macronutrient composition on sensor glucose time-in-target (TIT, 3.9-10.0 mmol/L) and mean sensor glucose were assessed with hierarchical linear models using a Bayesian estimation approach. TIT was lower and the mean sensor glucose slightly higher, after breakfast compared with lunch and dinner, whereas the insulin dose was higher. Across meals, when carbohydrates were replaced by fat, or to a lesser extent by protein, postprandial glucose control improved. For breakfast, a 3.9% improvement in TIT was observed when 10% of the energy from carbohydrates was replaced by fat. Improvements were slightly lower during lunch and dinner (3.2% and 3.4%) or when carbohydrates were replaced by protein (2.2 and 2.7%, respectively). We suggest that reducing carbohydrate at the expense of fat or protein, could further improve glucose control during fully closed-loop insulin therapy in hospital.

Effect of fully automated closed-loop insulin delivery using faster aspart versus standard aspart on gluco-regulatory hormones in type 2 diabetes

We retrospectively assessed gluco-regulatory hormones over 10 h (including two meals) of fully automated closed-loop insulin delivery using faster (FA) versus standard insulin aspart (IAsp) in adults with type 2 diabetes [n = 15, age 59 ± 10 years, body mass index 34.5 ± 9.1 kg/m² , glycated haemoglobin 7.7 ± 1.2% (60 ± 13 mmol/mol)]. Plasma concentration of human insulin, IAsp, C-peptide, glucagon, glucagon-like peptide 1, glucose-dependent insulinotropic peptide and peptide tyrosine tyrosine were measured every 15-30 min. Endogenous insulin secretion was calculated using C-peptide deconvolution and exposures to hormones were compared using their mean plasma concentrations. Ten-hour exposure of IAsp was higher with FA versus IAsp (P = .037) in line with the 10% higher insulin requirements to achieve similar glucose control. No significant difference was found for total insulin exposure and endogenous insulin secretion. Similarly, other gluco-regulatory hormones did not significantly differ. In conclusion, the faster pharmacokinetic profile and slightly higher aspart exposure of FA versus IAsp remained without significant effects on endogenous insulin secretion or other gluco-regulatory hormones. Further studies are warranted to explore the metabolic and endocrine effects of novel insulins with accelerated pharmacokinetic properties.