Variability of glucose-lowering effect as a limiting factor in optimizing basal insulin therapy: a review

How to improve the quality of euglycemic glucose clamp tests in long-acting insulin studies

BACKGROUND

The euglycemic clamp test stands as the best method for assessing the pharmacokinetic and pharmacodynamic properties of long-acting insulin. However, despite its widespread use, there remains a notable absence of an established gold standard for evaluating the test's quality. Existing recommendations from regulatory agencies lack specific threshold values, particularly concerning long-acting insulin. This study aimed to determine the evaluation criteria for assessing the quality of the long-acting insulin euglycemic glucose clamp test and to improve the overall quality of this testing method.

METHODS

Fifty-three healthy volunteers were administered a single dose of insulin degludec (0.4 IU/kg) and underwent a 24-h euglycemic clamp test. Blood samples were collected to evaluate the pharmacokinetics and pharmacodynamics of insulin degludec. Volunteers were separated into group A (coefficient of variation in blood glucose [CVBG] ≤ 3.5%) and group B (CVBG > 3.5%). The quality difference of the clamp test between the groups was assessed using various quality control indices. Volunteers were also categorized into group C (C-peptide reduction rate < 50%) and group D (C-peptide reduction rate ≥ 50%). The clamp test quality, pharmacokinetics, and pharmacodynamics of groups C and D were compared.

RESULTS

According to CVBG, group A had a mean CVBG of 2.95%, group B had a mean CVBG of 4.15%, and group A had a significantly lower CVBG than group B (p < 0.001). CVBG was positively correlated with other quality control indicators, such as the percentage of glucose excursion from the target range (GEFTR), duration of GEFTR, and area under the curve (AUC) of GEFTR. According to the reduction of C-peptide levels: group D had significantly higher C-peptide reduction than group C (p < 0.001). Groups C and D had CVBG < 3.5%. The quality of groups C and groups D was evaluated by the quality control indicators of the clamp test. Only the AUC of GEFTR was statistically different between Groups C and D (p = 0.043, < 0.05), and there was no statistical difference in other indicators between the two groups.

CONCLUSIONS

CVBG could be used as a standard for evaluating the quality of long-acting insulin euglycemic glucose clamp test, and the test quality was superior with a CVBG ≤ 3.5%. A C-peptide reduction ratio ≥ 50% indicated sufficient endogenous insulin inhibition; however, when the glucose fluctuation is small (CVBG is maintained at a low level) during the clamp test, even if the clamp test quality is slightly different, it is not sufficient to interfere with endogenous insulin secretion.

The effect of carbohydrate intake on glycaemic control in individuals with type 1 diabetes: a randomised, open-label, crossover trial

Background

Few studies have examined the effects of lower carbohydrate diets on glucose control in persons with type 1 diabetes (T1D). The objective of the study was to investigate whether a moderate carbohydrate diet improves glucose control in persons with T1D.

Methods

A randomised, multicentre, open-label, crossover trial over 12 weeks. There were 69 individuals assessed for eligibility, 54 adults with T1D and HbA1c ≥ 58 mmol/mol (7.5%) were randomised. Interventions were moderate carbohydrate diet versus traditional diet (30 vs 50% of total energy from carbohydrates) over four weeks, with a four-week wash-out period between treatments. Masked continuous glucose monitoring was used to evaluate effects on glucose control. The primary endpoint was the difference in mean glucose levels between the last 14 days of each diet phase.

Findings

50 individuals were included in the full analysis set with a mean baseline HbA1c of 69 mmol/mol (8.4%), BMI 29 kg/m2, age of 48 years, and 50% were female. The difference in mean glucose levels between moderate carbohydrate and traditional diet was -0.6 mmol/L, 95% CI -0.9 to -0.3, p < 0.001. Time in range increased during moderate carbohydrate diet by 4.7% (68 min/24 h) (95% CI 1.3 to 8.0), p = 0.008. Time above range (>10 mmol/L) decreased by 5.9% (85 min/24 h), 95% CI -9.6 to -2.2, p = 0.003. There were no significant differences in the standard deviation of glucose levels (95% CI -0.3 to 0.0 mmol/L, p = 0.15) or hypoglycaemia in the range <3.9 mmol/L (95% CI -0.4 to 2.9%, p = 0.13) and <3.0 mmol/L (95% CI -0.4 to 1.6%, p = 0.26). Four participants withdrew, none because of adverse events. There were no serious adverse events including severe hypoglycaemia and ketoacidosis. Mean ketone levels were 0.17 (SD 0.14) mmol/L during traditional and 0.18 (SD 0.13) mmol/L during moderate carbohydrate diet (p = 0.02).

Interpretation

A moderate carbohydrate diet is associated with decreases in mean glucose levels and time above range and increases in time in range without increased risk of hypoglycaemia or ketoacidosis compared with a traditional diet in individuals with T1D.

Funding

The Healthcare Board, Region Västra Götaland, The Dr P Håkansson Foundation and the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement [ALFGBG-966173].

How to Measure Glycemic Variability? A Literature Review

Optimal glycemic control without the presence of diabetes-related complications is the primary goal for adequate diabetes management. Recent studies have shown that hemoglobin A1c level cannot fully evaluate diabetes management as glycemic fluctuations are demonstrated to have a major impact on the occurrence of diabetes-related micro- and macroangiopathic comorbidities. The use of continuous glycemic monitoring systems allowed the quantification of glycemic fluctuations, providing valuable information about the patients' glycemic control through various indicators that evaluate the magnitude of glycemic fluctuations in different time intervals. This review highlights the significance of glycemic variability by describing and providing a better understanding of common and alternative indicators available for use in clinical practice.

Insulin Tregopil: An Ultra-Fast Oral Recombinant Human Insulin Analog: Preclinical and Clinical Development in Diabetes Mellitus

Insulin therapy is indispensable for achieving glycemic control in all patients with type 1 diabetes mellitus and many patients with type 2 diabetes mellitus. Insulin injections are associated with negative connotations in patients owing to administration discomfort and adverse effects such as hypoglycemia and weight gain. Insulin administered orally can overcome these limitations by providing a convenient and effective mode of delivery with a potentially lower risk of hypoglycemia. Oral insulin mimics the physiologic process of insulin secretion, absorption into the portal circulation, and subsequent peripheral delivery, unlike the subcutaneous route that results in peripheral hyperinsulinemia. Insulin tregopil (IN-105), a new generation human recombinant insulin, methoxy (polyethylene glycol) hexanoyl human recombinant insulin, is developed by Biocon as an ultra-fast onset short-acting oral insulin analog. This recombinant oral insulin is a single short-chain amphiphilic oligomer modified with the covalent attachment of methoxy-triethylene-glycol-propionyl moiety at Lys-β29-amino group of the B-chain via an amide linkage. Sodium caprate, an excipient in the insulin tregopil formulation, is a permeation enhancer that increases its absorption through the gastrointestinal tract. Also, meal composition has been shown to non-significantly affect its absorption. Several global randomized, controlled clinical trials have been conducted in type 1 and type 2 diabetes patients towards the clinical development of insulin tregopil. The formulation shows post-prandial glucose control that is more effective than placebo throughout the meal period; however, compared with an active comparator insulin aspart, the post-prandial control is more effective mainly in the early post-meal period. It shows a good safety profile with a lower incidence of clinically significant hypoglycemia. This review covers the overall clinical development of insulin tregopil establishing it as an ultra-fast onset, short-acting oral insulin analog for optimizing post-prandial glucose.

Design of a randomized cross-over study evaluating effects of carbohydrate intake on glycemic control in persons with type 1 diabetes

Introduction

Diet is an important factor in managing glycemic control in type 1 diabetes (T1D). Reducing carbohydrate intake may be important for stabilizing blood glucose levels in certain groups of patients with T1D. There are few studies examining the effects of a low carbohydrate diet in patients with T1D. The aim of this study is to investigate the effects of carbohydrate intake on glucose control in adults with T1D.

Materials and methods

Adults with T1D (N = 54) and inadequate glycemic control (HbA1c ≥ 7.5%; 58 mmol/mol) were randomized in a cross-over design to a moderate carbohydrate diet (30 percent of total energy from carbohydrates) versus a traditional diabetes diet (50 percent of total energy from carbohydrates) for 4 weeks with a between wash-out period of 4 weeks. Masked continuous glucose monitoring was used throughout the study to evaluate effects on mean blood glucose levels, time-in-range, hypoglycemia, hyperglycemia, and glycemic variability. Diabetes treatment satisfaction, hypoglycemic confidence, and physical activity were measured using questionnaires during different phases of the trial. HbA1c, blood lipids, blood pressure, and ketone levels were also measured. The primary endpoint is the difference in mean blood glucose level between the diet periods. Study completion is anticipated during winter 2022.

Discussion

The study seeks to increase knowledge about the effects of dietary carbohydrate intake on glycemic control and other health parameters in patients with T1D. If beneficial effects on mean blood glucose level without elevated risk of hypoglycemia or ketoacidosis are shown, a moderate carbohydrate diet may be a treatment option for people with T1D that have unsatisfactory blood glucose levels.

Clinical Trials Registration:www.clinicaltrials.gov, ID: NCT03400618.

Progressive Acceleration of Insulin Exposure Over 7 Days of Infusion Set Wear

Insulin exposure varies over 3 days of insulin infusion set (IIS) wear making day-to-day insulin dosing challenging for people with diabetes (PWD). Here we report insulin pharmacodynamic (PD) and pharmacokinetic (PK) data extending these observations to 7 days of IIS wear. PWD (A1C ≤8.5%, C-peptide <0.6 nmol/L, ≥6 months pump use) were enrolled in a crossover euglycemic clamp pilot study comparing conventional Teflon angled IISs with an investigational extended-wear IIS. PK/PD data from six participants were obtained for 5 h postbolus. Although PD data were unstable, PK profiles (pooled data from both groups) of insulin lispro (0.15 U/kg bolus) showed statistically significant progressive decreases from days 0 to 7 for t_max (P < 0.001), C_max (P < 0.05), and mean residence time (P < 0.0001). Area under the insulin concentration curve (AUC_0-300) declined by ∼24% from days 0 to 7 (P < 0.05). These results confirm/extend previous observations showing progressive acceleration of insulin exposure over IIS wear time. This may have implications for PWD and designers of closed-loop algorithms, although larger studies are necessary to confirm this. The study was registered in clinicaltrials.gov (NCT04398030).

Quantitative evaluation of insulin-induced abdominal subcutaneous dystrophic tissue using shear wave elastography

Aims/Introduction

Subcutaneous dystrophic tissue (DT) produced by insulin injection causes dysglycemia owing to inadequate absorption of insulin. However, precise techniques for measuring DT have not been established. Shear wave elastography (SWE) is an imaging technology that can quantify tissue stiffness. In this study, insulin injection‐induced DT was quantified using SWE to generate whole‐abdominal wall subcutaneous tissue by three‐dimensional (3D) imaging in patients with type 2 diabetes who were treated with multiple insulin injections.

Materials and Methods

Seven patients with type 2 diabetes were recruited who received long‐standing multiple insulin injections. Using SWE, the shear wave velocity (SWV) of DT and control (normal subcutaneous tissue) was measured. Furthermore, two of seven patients underwent whole‐abdominal SWE examination to calculate the proportion of DT. A subcutaneous insulin tolerance test was also performed in both the DT and control tissues.

Results

The SWV in DT was significantly higher than that in the control tissue (2.87 [2.66–2.98] vs 1.29 [1.23–1.44] m/s, P < 0.01). The proportion of the DT volume was 0.67% and 5.21% for two individuals from the entire abdominal subcutaneous tissue volume. The area under the curve for the subcutaneously injected insulin aspart concentration at the DT sites was lower than that of the control tissue (75.0 [52.1–111] vs 116 [86.9–152.5] h*mU/L, P = 0.1).

Conclusions

SWE can be useful in quantifying abdominal subcutaneous insulin‐induced DT, especially the 3D volume of insulin injection‐induced DT from the entire abdominal subcutaneous tissue. This study is the first to examine the volume and distribution of abdominal subcutaneous DT using SWE.

Deep Learning for Diabetes: A Systematic Review

Diabetes is a chronic metabolic disorder that affects an estimated 463 million people worldwide. Aiming to improve the treatment of people with diabetes, digital health has been widely adopted in recent years and generated a huge amount of data that could be used for further management of this chronic disease. Taking advantage of this, approaches that use artificial intelligence and specifically deep learning, an emerging type of machine learning, have been widely adopted with promising results. In this paper, we present a comprehensive review of the applications of deep learning within the field of diabetes. We conducted a systematic literature search and identified three main areas that use this approach: diagnosis of diabetes, glucose management, and diagnosis of diabetes-related complications. The search resulted in the selection of 40 original research articles, of which we have summarized the key information about the employed learning models, development process, main outcomes, and baseline methods for performance evaluation. Among the analyzed literature, it is to be noted that various deep learning techniques and frameworks have achieved state-of-the-art performance in many diabetes-related tasks by outperforming conventional machine learning approaches. Meanwhile, we identify some limitations in the current literature, such as a lack of data availability and model interpretability. The rapid developments in deep learning and the increase in available data offer the possibility to meet these challenges in the near future and allow the widespread deployment of this technology in clinical settings.

Effects of insulin degludec and insulin glargine U300 on glycaemic stability in individuals with type 1 diabetes: A multicentre, randomized controlled crossover study

To compare the effects of insulin degludec (IDeg) and insulin glargine U300 (IGlarU300) on glycaemic stability in subjects with type 1 diabetes.

MATERIALS AND METHODS

In this multicentre, crossover trial, 46 individuals with type 1 diabetes and essentially undetectable circulating C-peptide were randomly assigned to either the IDeg-first/IGlarU300-second group or the IGlarU300-first/IDeg-second group, and were treated with the respective basal insulins for 4-week periods. Data were collected in the last week of each treatment period. The primary aim was to examine the potential non-inferiority of IDeg relative to IGlarU300 with regard to day-to-day variability, as evaluated by the standard deviation (SD) of fasting blood glucose (FBG) levels. Intra-day glycaemic variability and other variables were also determined by continuous glucose monitoring (CGM).

RESULTS

The SD of FBG for IDeg was non-inferior to that for IGlarU300. The mean of FBG, coefficient of variation of FBG, and various glycaemic variability indexes determined by CGM did not differ between the two insulins. Whereas the administered doses of the insulins also did not differ, the mean glycaemic value was lower for IDeg than IGlarU300; the time above the target range (>180 mg/dL [10.0 mmol/L]) and the time below the target range (<70 mg/dL [3.9 mmol/L]) were shorter and longer, respectively, for IDeg than IGlarU300.

CONCLUSIONS

Our data suggest that IDeg and IGlarU300 have comparable glucose-stabilizing effects in individuals with type 1 diabetes. However, the glucose-lowering effect of IDeg may be greater than that of IGlarU300 when titrated with a unit-based protocol.

Pharmacokinetics, tissue distribution and excretion of a novel long-acting human insulin analogue - recombinant insulin LysArg in rats

As a novel long-acting recombinant human insulin analogue, it is necessary to carry out the preclinical research for insulin LysArg. The purpose of this study was to characterise the pharmacokinetic, tissue distribution and excretion of insulin LysArg and provide a reference for its development. Three methods were used to measure the content of insulin LysArg in biological samples after a single subcutaneous administration in rats, including radioassay, radioassay after precipitation with TCA and separation by HPLC. After Subcutaneous administration of recombinant insulin LysArg 1, 2, 4 U/kg in rats, it showed both C_max and AUC_0-t were positively correlated with the dose. In the meanwhile, after a single subcutaneous administration of recombinant insulin LysArg at 2 U/kg in rats, the amount of radioactivity in most organs was highest at 1.5 h and then decreased gradually, no accumulation was found. The highest level of insulin LysArg was observed in the kidney. Like other macromolecules, insulin LysArg was mainly excreted from urine. The study fully illustrated the pharmacokinetic pattern of insulin LysArg, provided valuable informations to support its further development about safety and toxicology.

Nicotine-mediated upregulation of microRNA-141 expression determines adipokine-intervened insulin resistance

MicroRNAs (miRNAs) are non-coding RNAs that are associated with adipokine homeostasis and insulin resistance. Whereas, smoking can disturb metabolic homeostasis. Present study was aimed to investigate the level of miRNA-141 in experimental animal model that were exposed with graded doses of nicotine. We further aimed to investigate the possible interplay of miRNA-141 expression change with adipokine homeostasis and occurrence of insulin resistance in nicotine-exposed experimental animals. Nicotine (0.5, 1.0, 3.0 and 6.0 mg/Kg) was administered to early adolescent; postnatal days ranging from 25 to 30 Wistar rats for one month. Serum was analyzed for leptin, adipokines, IL-6, MDA, HbA1c, insulin, G6PDH, hexokinase, and lipid profile. While miRNA-141 expression level was determined in plasma. Higher doses of nicotine were associated with higher glucose, HbA1c, leptin, IL-6, MDA and lipids levels, while, insulin, adiponectin, G6PDH, hexokinase and HDL levels were lower. Higher doses of nicotine also impaired glucose tolerance and exhibited significant increase in miR-141 expression signifying that nicotine exposure may influence adipokines regulation altering glycemic profile. This is accompanied with aggravated inflammatory responses where genetic expression of miRNA-141 can be an accessible biomarker for metabolic disturbances with insulin resistance and glucose intolerance.

Understanding the Clinical Profile of Insulin Degludec, the Latest Basal Insulin Approved for Use in Canada: a Narrative Review

In recent years, the development of basal insulin therapies has focused on insulin analogues that have longer durations of action and more predictable pharmacokinetic/pharmacodynamic (PK/PD) profiles than their human insulin-based predecessors, such as neutral protamine Hagedorn (NPH) insulin. Dosed once-daily, such analogues can provide a more stable glucose-lowering action, which translates clinically into a reduced risk of hypoglycemia. Insulin degludec (degludec) became available in Canada in 2017 and is the first basal insulin analogue to have a half-life exceeding the dosing interval. As well as offering the promise of an exceptionally flat PK/PD profile when at steady state, this characteristic means that insulin degludec can be dosed with some flexibility with regard to time of day and that it need not be taken at the same time each day. However, the approximately 25-h half-life also has some implications concerning dose titration. This article provides an up-to-date review of the study data describing the clinical profile of degludec, and aims to give helpful and practical advice to prescribers about its use. While the clinical benefits of degludec are described, it is also acknowledged that further study is required to better understand how its clinical performance compares with that of insulin glargine 300 units/mL.

Resolution on the results of the first working meeting of the scientific advisory board «Actual problems of glycemic variability as a new criterion of glycemic control and safety of diabetes therapy»

The Scientific Advisory Board, chaired by Professor G. R. Galstyan (cochair - A.V. Zilov), met in Moscow on 19 June 2018 to discuss the possibilities of improving the results of diabetes mellitus (DM) treatment by considering glycaemic variability (GV) as an additional criterion for effective glycaemic control (especially in patients receiving insulin therapy) and as one of the goals of treatment in patients with unstable glycaemia. The purpose of the working meeting was to develop a strategy for the introduction of GV as a predictor and as an additional criterion for assessing the effectiveness and safety of hypoglycaemic therapy to improve the pharmacotherapy of diabetes and reduce cardiovascular and total mortality. The aims of the working meeting were to conduct a comprehensive data analysis of the relationship between GV and hypoglycaemia; to gather and analyse published data and the experience of decrease in GV and improved outcomes of diabetes against the background of different types of insulin therapy; to compare existing methods of glycaemia monitoring and GV assessment and examine their validity and availability in real practice in the context of limited budget and to analyse the informativeness and clinical and prognostic significance of various parameters of GV assessment and to determine their reasonable minimum for a comprehensive assessment of GV as a criterion for evaluating the effectiveness of DM treatment and the predictors of negative diabetes outcomes. The following reports were presented during the discussion: Glycemic variability: clinical and prognostic value. Types of glycemic variability (Candidate of Medical Sciences, assistant Professor Zilov A.V.); Methods of assessment of variability of glycemia in clinical trials and routine practice (PhD, Professor Markova T. N.); Current international and national recommendations on glycemic monitoring (PhD, Professor Galstyan G. R.) and Peculiarities of glycemic variability and its evaluation among children and adolescents (Candidate of Medical Sciences Vitebskaya A.V.).

Basal insulin therapy: Unmet medical needs in Asia and the new insulin glargine in diabetes treatment

Diabetes remains a global epidemic and a tremendous health challenge, especially in the Asian population. Dramatic increases in the prevalence of diabetes across different countries or areas in Asia have been reported in recent epidemiological studies. Although clinical guidelines have strengthened appropriate antihyperglycemic medications and lifestyle modifications for optimal diabetes management, inadequate glycemic control still occurs in many patients with an increased risk of developing microvascular and macrovascular complications. Insulin administration is the main therapy for diabetes in response to the inability to secrete insulin, and is recommended in current guidelines to treat patients with type 2 diabetes after failure of oral antidiabetic drugs. Clinical studies have shown that long-acting insulin analogs improve basal glycemic control with reduced risk of hypoglycemia. In the present review, we discuss previous challenges with basal insulin therapy in Asia, the pharmacological development of insulin analogs to overcome the unmet medical needs and recent clinical studies of the new ultra-long-acting insulin analog, insulin glargine U300. Furthermore, relevant findings of current real-world evidence are also included for the comparison of the efficacy and safety of different insulin formulations. Based on the accumulating evidence showing a low incidence of hypoglycemia and technical benefits of dose titration, treatment with glargine U300 can be a promising strategy for Asian diabetes patients to achieve glycemic targets with favorable safety.

Efficacy and safety of oral basal insulin versus subcutaneous insulin glargine in type 2 diabetes: a randomised, double-blind, phase 2 trial

BACKGROUND

Oral insulin 338 (I338) is a long-acting, basal insulin analogue formulated in a tablet with the absorption-enhancer sodium caprate. We investigated the efficacy and safety of I338 versus subcutaneous insulin glargine (IGlar) in patients with type 2 diabetes.

METHODS

This was a phase 2, 8-week, randomised, double-blind, double-dummy, active-controlled, parallel trial completed at two research institutes in Germany. Insulin-naive adult patients with type 2 diabetes, inadequately controlled on metformin monotherapy or combined with other oral antidiabetic drugs (HbA_1c 7·0-10·0%; BMI 25·0-40·0 kg/m²), were randomly assigned (1:1) to receive once-daily I338 plus subcutaneous placebo (I338 group) or once-daily IGlar plus oral placebo (IGlar group). Randomisation occurred by interactive web response system stratified by baseline treatment with oral antidiabetic drugs. Patients and investigators were masked to treatment assignment. Weekly insulin dose titration aimed to achieve a self-measured fasting plasma glucose (FPG) concentration of 4·4-7·0 mmol/L. The recommended daily starting doses were 2700 nmol I338 or 10 U IGlar, and maximum allowed doses throughout the trial were 16 200 nmol I338 or 60 U IGlar. The primary endpoint was treatment difference in FPG concentration at 8 weeks for all randomly assigned patients receiving at least one dose of trial product (ie, the full analysis set). The trial has been completed and is registered at ClinicalTrials.gov, number NCT02470039.

FINDINGS

Between June 1, 2015, and Oct 19, 2015, 82 patients were screened for eligibility and 50 patients were randomly assigned to the I338 group (n=25) or the IGlar group (n=25). Mean FPG concentration at baseline was 9·7 (SD 2·8) in the I338 group and 9·1 (1·7) in the IGlar group. Least square mean FPG concentration at 8 weeks was 7·1 mmol/L (95% CI 6·4-7·8) in the I338 group and 6·8 mmol/L (6·5-7·1) in the IGlar group, with no significant treatment difference (0·3 mmol/L [-0·5 to 1·1]; p=0·46). I338 and IGlar were well tolerated by patients. Adverse events were reported in 15 (60%) patients in the I338 group and 17 (68%) patients in the IGlar group. The most common adverse events were diarrhoea (three [12%] patients in each group) and nasopharyngitis (five [20%] in the I338 group and two [8%] in the IGlar group). Most adverse events were graded mild (47 of 68 events), and no severe adverse events were reported. One patient in the IGlar group had a treatment-emergent serious adverse event (urogenital haemorrhage of moderate intensity, assessed by the investigator as unlikely to be related to treatment; the patient recovered). Incidence of hypoglycaemia was low in both groups (n=7 events in the I338 group; n=11 in the IGlar group), with no severe episodes.

INTERPRETATION

I338 can safely improve glycaemic control in insulin-naive patients with type 2 diabetes with no evidence of a difference compared with insulin glargine, a widely used subcutaneously administered basal insulin. Further development of this particular oral insulin project was discontinued because I338 doses were high and, therefore, production of the required quantities of I338 for wide public use was deemed not commercially viable. Improvement of technologies involved in the product's development is the focus of ongoing research.

FUNDING

Novo Nordisk.

Day-to-day fasting self-monitored blood glucose variability is associated with risk of hypoglycaemia in insulin-treated patients with type 1 and type 2 diabetes: A post hoc analysis of the SWITCH Trials

AIMS

To investigate the association between day-to-day fasting self-monitored blood glucose (SMBG) variability and risk of hypoglycaemia in type 1 (T1D) and type 2 diabetes (T2D), and to compare day-to-day fasting SMBG variability between treatments with insulin degludec (degludec) and insulin glargine 100 units/mL (glargine U100).

MATERIALS AND METHODS

Data were retrieved from two double-blind, randomized, treat-to-target, two-period (32 weeks each) crossover trials of degludec vs glargine U100 in T1D (SWITCH 1, n = 501) and T2D (SWITCH 2, n = 720). Available fasting SMBGs were used to determine the standard deviation (SD) of day-to-day fasting SMBG variability for each patient and the treatment combination. The association between day-to-day fasting SMBG variability and overall symptomatic, nocturnal symptomatic and severe hypoglycaemia was analysed for the pooled population using linear regression, with fasting SMBG variability included as a three-level factor defined by population tertiles. Finally, day-to-day fasting SMBG variability was compared between treatments.

RESULTS

Linear regression showed that day-to-day fasting SMBG variability was significantly associated with overall symptomatic, nocturnal symptomatic and severe hypoglycaemia risk in T1D and T2D (P < 0.05). Day-to-day fasting SMBG variability was significantly associated (P < 0.01) with all categories of hypoglycaemia risk, with the exception of severe hypoglycaemia in T2D when analysed within tertiles. Degludec was associated with 4% lower day-to-day fasting SMBG variability than glargine U100 in T1D (P = 0.0082) and with 10% lower day-to-day fasting SMBG variability in T2D (P < 0.0001).

CONCLUSIONS

Higher day-to-day fasting SMBG variability is associated with an increased risk of overall symptomatic, nocturnal symptomatic and severe hypoglycaemia. Degludec has significantly lower day-to-day fasting SMBG variability vs glargine U100.

Efficacy and safety of Subetta add-on therapy in type 1 diabetes mellitus: The results of a multicenter, double-blind, placebo-controlled, randomized clinical trial

BACKGROUND

To examine efficacy of Subetta as an add-on to insulin therapy in patients with type 1 diabetes mellitus (T1DM) a multicenter, double-blind, placebo-controlled, randomized clinical trial was performed. Derived by technological treatment of antibodies to insulin receptor β-subunit and endothelial NO synthase Subetta was previously proved to activate insulin signaling pathway.

METHODS

A total of 144 randomized patients with poor glycemic control in basal-bolus insulin regime were included in intention-to-treat analysis in Subetta add-on therapy or placebo (n = 72 in both groups). Hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), basal and prandial insulin doses, number of hypoglycemia episodes confirmed by self-monitoring of blood glucose were recorded for 36 weeks.

RESULTS

The baseline characteristics of subjects did not differ between the two groups. HbA1c mean (±standard deviation) change was -0.59 ± 0.99% (95% CI -0.84 to -0.37) after 36 weeks in Subetta (vs. -0.20 ± 1.14%; 95% CI -0.44 to 0.11 in placebo; p = 0.028). The rate of overall hypoglycemia events was 7.9 per patient year (95% CI 7.1-8.6) in Subetta group and 7.6 (95% CI 6.9-8.4) in Placebo group (p = 0.63). The basal and total insulin doses did not change at the end of 36 weeks in both groups.

CONCLUSIONS

Subetta add-on therapy boosting insulin activity and improving glycemic control in patients with T1DM is proved to be beneficial.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01868594.

Day-to-Day and Within-Day Variability in Glucose-Lowering Effect Between Insulin Degludec and Insulin Glargine (100 U/mL and 300 U/mL): A Comparison Across Studies

BACKGROUND

Insulin degludec (IDeg) has significantly lower day-to-day and within-day variability compared to insulin glargine (IGlar) 100U/mL (U100) and 300U/mL (U300). Here, we report post hoc assessments to confirm the robustness of these observations while accounting for potential experimental confounders.

METHODS

Two euglycemic clamp studies in type 1 diabetes patients, comparing IDeg to IGlar-U100 (Study A, parallel design, 54 patients; Study B, crossover, 22 patients) and one study comparing IDeg to IGlar-U300 (Study C, crossover, 57 patients), all dosed at 0.4U/kg, were evaluated. Pharmacodynamic parameters were assessed at steady state from glucose infusion rate (GIR) profiles following three 24-hour euglycemic clamps in Studies A (162 clamps) and C (342 clamps), and one 42-hour clamp in Study B (44 clamps).

RESULTS

Pooled data (Studies A and B) showed that IDeg had an even distribution of glucose-lowering effect over the 24-hour dosing interval that was consistent with Study C. IGlar-U100 showed a constant decrease in glucose-lowering effect over 24 hours while IGlar-U300 had a lower effect in the middle of the dosing interval (6-18 hours). Relative within-day variability of IDeg was 40% and 37% lower than IGlar-U100 and -U300, respectively. Exclusion of profiles with low response in Study C (19/342 clamps) did not impact the difference in the distribution of glucose-lowering effect or within-day variability. Day-to-day variability was significantly lower with IDeg compared to IGlar-U100 and -U300 based on smoothed and unsmoothed GIR data.

CONCLUSIONS

Significantly lower relative within-day and day-to-day variability was confirmed irrespective of experimental considerations for IDeg compared to IGlar-U100 and IGlar-U300.

Pharmacokinetic and Pharmacodynamic Properties of Faster-Acting Insulin Aspart versus Insulin Aspart Across a Clinically Relevant Dose Range in Subjects with Type 1 Diabetes Mellitus

Background

Absorption of current rapid-acting insulins is too slow for patients with diabetes mellitus to achieve optimal postprandial glucose control. Faster-acting insulin aspart (faster aspart) is insulin aspart in a new formulation with faster early absorption. We compared the pharmacokinetic/pharmacodynamic properties of faster aspart and insulin aspart across a clinically relevant dose range.

Methods

In this randomised, double-blind, crossover trial, 46 subjects with type 1 diabetes mellitus received single subcutaneous doses of faster aspart and insulin aspart at 0.1, 0.2 (repeated three times to estimate within-subject variability) and 0.4 U/kg in a euglycaemic clamp setting (target 5.5 mmol/L).

Results

Consistently for the three doses, faster aspart demonstrated faster onset and greater early absorption and glucose-lowering effect versus insulin aspart. Across all three doses, onset of appearance occurred approximately twice as fast (approximately 5 min earlier) and early insulin exposure (AUC_{IAsp,0–30min}) was approximately 1.5- to 2-fold greater for faster aspart versus insulin aspart. Likewise, onset of action occurred approximately 5 min faster and early glucose-lowering effect (AUC_{GIR,0–30min}) was approximately 1.5- to 2-fold larger for faster aspart versus insulin aspart. Relative bioavailability was approximately 100% and total glucose-lowering effect was similar for faster aspart versus insulin aspart. Dose–concentration and dose–response relationships were comparable between faster aspart and insulin aspart. Within-subject variability in glucose-lowering effect was low for faster aspart (coefficient of variation approximately 20%) and not significantly different from insulin aspart.

Conclusion

The faster onset and greater early insulin exposure and glucose-lowering effect with faster aspart versus insulin aspart are preserved across a broad range of doses and consistently observed from day to day.

ClinicalTrials.gov identifier

NCT02033239.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-016-0473-5) contains supplementary material, which is available to authorized users.

Factors Affecting the Absorption of Subcutaneously Administered Insulin: Effect on Variability

Variability in the effect of subcutaneously administered insulin represents a major challenge in insulin therapy where precise dosing is required in order to achieve targeted glucose levels. Since this variability is largely influenced by the absorption of insulin, a deeper understanding of the factors affecting the absorption of insulin from the subcutaneous tissue is necessary in order to improve glycaemic control and the long-term prognosis in people with diabetes. These factors can be related to either the insulin preparation, the injection site/patient, or the injection technique. This review highlights the factors affecting insulin absorption with special attention on the physiological factors at the injection site. In addition, it also provides a detailed description of the insulin absorption process and the various modifications to this process that have been utilized by the different insulin preparations available.

Insulin-associated weight gain in obese type 2 diabetes mellitus patients: What can be done?

Insulin therapy (IT) is initiated for patients with type 2 diabetes mellitus when glycaemic targets are not met with diet and other hypoglycaemic agents. The initiation of IT improves glycaemic control and reduces the risk of microvascular complications. There is, however, an associated weight gain following IT, which may adversely affect diabetic and cardiovascular morbidity and mortality. A 3 to 9 kg insulin-associated weight gain (IAWG) is reported to occur in the first year of initiating IT, predominantly caused by adipose tissue. The potential causes for this weight gain include an increase in energy intake linked to a fear of hypoglycaemia, a reduction in glycosuria, catch-up weight, and central effects on weight and appetite regulation. Patients with type 2 diabetes who are receiving IT often have multiple co-morbidities, including obesity, that are exacerbated by weight gain, making the management of their diabetes and obesity challenging. There are several treatment strategies for patients with type 2 diabetes, who require IT, that attenuate weight gain, help improve glycaemic control, and help promote body weight homeostasis. This review addresses the effects of insulin initiation and intensification on IAWG, and explores its potential underlying mechanisms, the predictors for this weight gain, and the available treatment options for managing and limiting weight gain.

A Review of Insulin Degludec/Insulin Aspart: Pharmacokinetic and Pharmacodynamic Properties and Their Implications in Clinical Use

Insulin degludec/insulin aspart (IDegAsp; 70 % IDeg and 30 % IAsp) is a soluble combination of two individual insulin analogues in one product, designed to provide mealtime glycaemic control due to the IAsp component and basal glucose-lowering effect from the IDeg component. The pharmacokinetic and pharmacodynamic characteristics of IDegAsp have been investigated in a series of clinical pharmacology studies with generally comparable designs, methodologies and patient inclusion/exclusion criteria. The glucose-lowering effect profile of IDegAsp during once-daily dosing at steady state shows distinct and clearly separated action from the prandial and basal components of IDegAsp. The IAsp component provides rapid onset and peak glucose-lowering effect followed by a flat glucose-lowering effect lasting beyond 30 h due to IDeg. During twice-daily dosing, the distinct peak effect and the flat basal effect are retained following each dose. The pharmacological properties of IDegAsp are maintained in the elderly, children, adolescents, Japanese patients and those with hepatic or renal impairment. The potential clinical benefits associated with the pharmacological properties of IDegAsp have been verified in phase III clinical trials comparing IDegAsp with three other currently available treatment options: premixed insulin, basal-bolus regimens and basal-only therapy. IDegAsp shows favourable clinical benefits compared with biphasic insulin aspart 30 and is a viable alternative to basal-bolus and basal-only therapy. This review presents the results from clinical pharmacology studies conducted with IDegAsp to date, and extrapolates these results to clinical use of IDegAsp in the context of findings from the IDegAsp clinical therapeutic studies.

The potential effect of ultra-long insulin degludec on glycemic variability

Despite the therapeutic advances in the treatment of diabetes, metabolic control instability due to glycemic variability (GV) is frequently observed in patients with diabetes on intensive insulin therapy and is associated with hyperglycemic peaks and hypoglycemic episodes. Hyperglycemia associated with GV has been implicated in the development of chronic complications due to its pro-oxidative consequences. On the other hand, hypoglycemia can be associated with increased cardiovascular risk secondarily to adrenergic activation. The ultra-long-acting insulin analogue, insulin degludec (IDeg), presents a flat and stable glucose-lowering effect both in Type 1 and Type 2 diabetes patients. In pharmacodynamic studies, IDeg has been associated with a lower variability in its insulin action than other alternatives for basal insulin, which might have clinical advantages for the stability of the glycemic control. The main objective of this review is to present pharmacological and clinical data regarding the efficacy and safety of IDeg for the treatment of diabetes focusing on its effects on GV and on hypoglycemia frequency.

Internalization and localization of basal insulin peglispro in cells

BACKGROUND

Basal insulin peglispro (BIL) is a novel, PEGylated insulin lispro that has a large hydrodynamic size compared with insulin lispro. It has a prolonged duration of action, which is related to a delay in insulin absorption and a reduction in clearance. Given the different physical properties of BIL compared with native insulin and insulin lispro, it is important to assess the cellular internalization characteristics of the molecule.

METHODS AND MATERIALS

Using immunofluorescent confocal imaging, we compared the cellular internalization and localization patterns of BIL, biosynthetic human insulin, and insulin lispro. We assessed the effects of BIL on internalization of the insulin receptor (IR) and studied cellular clearance of BIL.

RESULTS

Co-localization studies using antibodies to either insulin or PEG, and the early endosomal marker EEA1 showed that the overall internalization and subcellular localization pattern of BIL was similar to that of human insulin and insulin lispro; all were rapidly internalized and co-localized with EEA1. During ligand washout for 4 h, concomitant loss of insulin, PEG methoxy group, and PEG backbone immunostaining was observed for BIL, similar to the loss of insulin immunostaining observed for insulin lispro and human insulin. Co-localization studies using an antibody to the lysosomal marker LAMP1 did not reveal evidence of lysosomal localization for insulin lispro, human insulin, BIL, or PEG using either insulin or PEG immunostaining reagents. BIL and human insulin both induced rapid phosphorylation and internalization of human IR.

CONCLUSIONS

Our findings show that treatment of cells with BIL stimulates internalization and localization of IR to early endosomes. Both the insulin and PEG moieties of BIL undergo a dynamic cellular process of rapid internalization and transport to early endosomes followed by loss of cellular immunostaining in a manner similar to that of insulin lispro and human insulin. The rate of clearance for the insulin lispro portion of BIL was slower than the rate of clearance for human insulin. In contrast, the PEG moiety of BIL can recycle out of cells.

Oral Insulin Delivery in a Physiologic Context: Review

Insulin remains indispensable to the treatment of diabetes, but its availability in injectable form only has hampered its timely and broader use. The development of an oral insulin remains an ultimate goal to both enhance ease of use, and to provide therapeutic advantages rooted in its direct delivery to the portal vein and liver. By mimicking the physiological path taken by pancreatic insulin, oral insulin is expected to have a distinct effect on the hepatic aspect of carbohydrate metabolism, hepatic insulin resistance, and, at the same time, avoid hyperinsulinemia and minimize the risk of hypoglycemia. With oral insulin approaching late stages of development, the goal of this review is to examine oral insulin in a physiological context and report on recent progress in its development.

The role of the new basal insulin analogs in addressing unmet clinical needs in people with type 1 and type 2 diabetes

BACKGROUND

Despite improvements in anti-hyperglycemic therapies, there are many unmet clinical needs that hinder successful glycemic control in people being treated with current basal insulin analogs.

OBJECTIVE

This paper reviews the unmet needs associated with current basal insulin therapy and describes the most recent basal insulins for the treatment of diabetes.

METHODS

PubMed was searched for articles on basal insulin analogs published between 2000 and April 2016.

RESULTS

Although long-acting insulin analogs, such as insulin glargine 100 units/mL and insulin detemir, have come towards approximating physiologic basal insulin levels, limitations such as hypoglycemia and intra- and inter-individual variability are associated with their use resulting in glycemic fluctuations. Some basal insulins lack 24 hour coverage, requiring some patients to split their dose, increasing the number of injections required to maintain glycemic control. Fear of hypoglycemia and the need for additional injections often leads to poor compliance and suboptimal glycemic control. Long-acting insulin analogs, such as insulin glargine 300 units/mL and insulin degludec, have improved upon the shortcomings of the current basal insulin analogs. Improved pharmacodynamic/pharmacokinetic profiles afford lower intra-patient variability and an extended duration of action, providing full and stable 24 hour basal insulin coverage with once daily dosing, and comparable efficacy to insulin glargine with lower rates of hypoglycemia.

CONCLUSION

The improved pharmacodynamic/pharmacokinetic profiles of new long-acting insulin formulations provide greater glycemic control with once daily dosing. With the growing number of therapeutic choices available, physicians have more scope to individualize patient options for basal insulin therapy.

Addition of 20-kDa PEG to Insulin Lispro Alters Absorption and Decreases Clearance in Animals

PURPOSE

Determine the pharmacokinetics of insulin peglispro (BIL) in 5/6-nephrectomized rats and study the absorption in lymph duct cannulated (LDC) sheep.

METHODS

BIL is insulin lispro modified with 20-kDa linear PEG at lysine B28 increasing the hydrodynamic size to 4-fold larger than insulin lispro. Pharmacokinetics of BIL and insulin lispro after IV administration were compared in 5/6-nephrectomized and sham rats. BIL was administered IV or SC into the interdigital space of the hind leg, and peripheral lymph and/or serum samples were collected from both LDC and non-LDC sheep to determine pharmacokinetics and absorption route of BIL.

RESULTS

The clearance of BIL was similar in 5/6-nephrectomized and sham rats, while the clearance of insulin lispro was 3.3-fold slower in 5/6-nephrectomized rats than in the sham rats. In non-LDC sheep, the terminal half-life after SC was about twice as long vs IV suggesting flip-flop pharmacokinetics. In LDC sheep, bioavailability decreased to <2%; most of the dose was absorbed via the lymphatic system, with 88% ± 19% of the dose collected in the lymph after SC administration.

CONCLUSION

This work demonstrates that increasing the hydrodynamic size of insulin lispro through PEGylation can impact both absorption and clearance to prolong drug action.

Similar HbA1c reduction and hypoglycaemia with variable- vs fixed-time dosing of basal insulin peglispro in type 1 diabetes: IMAGINE 7 study

AIMS

To compare 24-hour fixed-time basal insulin peglispro (BIL) dosing with 8- to 40-hour variable-time BIL dosing for glycaemic control and safety in patients with type 1 diabetes. Primary outcome was non-inferiority of BIL variable-time dosing compared with fixed-time dosing for glycated haemoglobin (HbA1c) change after 12-week treatment (margin = 0.4%).

MATERIALS AND METHODS

This Phase 3, open-label, randomized, cross-over study (N = 212) was conducted at 20 centres in the United States. During the 12-week lead-in phase, patients received BIL daily at fixed-times. Two 12-week randomized cross-over treatment phases followed, where patients received BIL dosed at either fixed- or variable-times. During the 4-week safety follow-up, patients received conventional insulins.

RESULTS

During the lead-in period, least-squares mean HbA1c decreased from 7.5% to 6.8%. For BIL, variable-time dosing was non-inferior to fixed-time dosing for HbA1c change [least-squares mean difference = 0.06%, 95% confidence interval (-0.01, 0.13)]. In both regimens, HbA1c increased slightly during the cross-over periods, but remained significantly below baseline. Variable- and fixed-time dosing regimens had similar rates of total hypoglycaemia (10.4 ± 0.62 and 10.5 ± 0.67 events/patient/30 days, P = .947) and nocturnal hypoglycaemia (1.3 ± 0.11 and 1.5 ± 0.13 events/patient/30days, P = .060). Comparable proportions of patients achieved HbA1c < 7.0% with variable- [91 (54.5%)] and fixed-time dosing [101 (60.5%)].

CONCLUSIONS

Treatment with BIL allows patients to use flexible dosing intervals from 8 to 40 hours. Glycaemic efficacy (HbA1c), glycaemic variability and hypoglycaemia are similar to fixed-time dosing, suggesting that BIL could potentially provide flexibility in dosing for patients who miss their daily basal insulin.

Insulin Injection Into Lipohypertrophic Tissue: Blunted and More Variable Insulin Absorption and Action and Impaired Postprandial Glucose Control

OBJECTIVE

Lipohypertrophy (LHT) is common in insulin-treated patients but its exact impact on insulin absorption and action is unclear.

RESEARCH DESIGN AND METHODS

In this crossover study, 13 patients with type 1 diabetes received subcutaneous abdominal injections of 0.15 units/kg insulin lispro into LHT (confirmed by examination and ultrasound) and normal adipose tissue (NAT). On one day, a euglycemic clamp was performed with two injections each into LHT and NAT, and on another day one injection per region was given before a standardized mixed meal (75 g carbohydrates), all in randomized order.

RESULTS

Compared with NAT, LHT reduced insulin absorption (mean area under the insulin concentration curve [AUCINS0-4h] 131 vs. 165 h * mU/L [LHT vs. NAT]; Cmax 61 vs. 79 mU/L, P < 0.02, respectively) and effect (areas under glucose infusion rate [GIR] curves [AUCGIR0-4h 625 vs. 775 mg/kg, P < 0.05]) but increased intrasubject variability ([coefficient of variation] AUCINS0-4h 52 vs. 11%, Cmax 55 vs. 15%, AUCGIR0-4h 57 vs. 23%, all P < 0.01). Postprandial blood glucose (BG) concentrations were ≥26% higher with LHT (AUCBG0-5h 731 vs. 513 mg * h/dL, BGmax 199 vs. 157 mg/dL, 2-h BG 150 vs. 104 mg/dL, 5-h BG 145 vs. 81 mg/dL, all P < 0.05) and maximum concentrations occurred later. Hypoglycemia (BG ≤50 mg/dL) occurred numerically less frequently with LHT injection (two vs. six patients), whereas profound hyperglycemia (BG ≥300 mg/dL) only occurred with LHT injection (two patients). Tmax-INS did not differ between LHT and NAT in either study.

CONCLUSIONS

Insulin absorption and action are blunted and considerably more variable with LHT injection, leading to profound deterioration in postprandial glucose control.

Resveratrol improves glycemic control in insulin-treated diabetic rats: participation of the hepatic territory

BACKGROUND

Resveratrol is a natural polyphenol that has been proposed to improve glycemic control in diabetes, by mechanisms that involve improvement in insulin secretion and activity. In type 1 diabetes (T1D), in which insulin therapy is obligatory, resveratrol treatment has never been investigated. The present study aimed to evaluate resveratrol as an adjunctive agent to insulin therapy in a T1D-like experimental model.

METHODS

Rats were rendered diabetic by streptozotocin (STZ) treatment. Twenty days later, four groups of animals were studied: non-diabetic (ND); diabetic treated with placebo (DP); diabetic treated with insulin (DI) and diabetic treated with insulin plus resveratrol (DIR). After 30 days of treatment, 24-hour urine was collected; then, blood, soleus muscle, proximal small intestine, renal cortex and liver were sampled. Specific glucose transporter proteins were analyzed (Western blotting) in each territory of interest. Solute carrier family 2 member 2 (Slc2a2), phosphoenolpyruvate carboxykinase (Pck1) and glucose-6-phosphatase catalytic subunit (G6pc) mRNAs (qPCR), glycogen storage and sirtuin 1 (SIRT1) activity were analyzed in liver.

RESULTS

Diabetes induction increased blood glucose, plasma fructosamine concentrations, and glycosuria. Insulin therapy partially recovered the glycemic control; however, resveratrol as adjunctive therapy additionally improved glycemic control and restored plasma fructosamine concentration to values of non-diabetic rats. Resveratrol did not alter the expression of the glucose transporters GLUT2 and SGLT1 in the intestine, GLUT2 and SGLT2 in kidney and GLUT4 in soleus, suggesting that fluxes of glucose in these territories were unaltered. Differently, in liver, resveratrol promoted a reduction in Slc2a2, Pck1, and G6pc mRNAs, as well as in GLUT2 protein (P < 0.05, DIR vs. DI); besides, it increased (P < 0.01, DIR vs. DI) the hepatic glycogen content, and SIRT1 protein.

CONCLUSIONS

Resveratrol is able to improve glycemic control in insulin-treated T1D-like rats. This effect seems not to involve changes in glucose fluxes in the small intestine, renal proximal tubule, and soleus skeletal muscle; but to be related to several changes in the liver, where downregulation of Slc2a2/GLUT2, Pck1, and G6pc expression was observed, favoring reduction of glucose production and efflux. Besides, resveratrol increased SIRT1 nuclear protein content in liver, which may be related to the observed gene expression regulations.

In Vivo and In Vitro Characterization of Basal Insulin Peglispro: A Novel Insulin Analog

The aim of this research was to characterize the in vivo and in vitro properties of basal insulin peglispro (BIL), a new basal insulin, wherein insulin lispro was derivatized through the covalent and site-specific attachment of a 20-kDa polyethylene-glycol (PEG; specifically, methoxy-terminated) moiety to lysine B28. Addition of the PEG moiety increased the hydrodynamic size of the insulin lispro molecule. Studies show there is a prolonged duration of action and a reduction in clearance. Given the different physical properties of BIL, it was also important to assess the metabolic and mitogenic activity of the molecule. Streptozotocin (STZ)-treated diabetic rats were used to study the pharmacokinetic and pharmacodynamic characteristics of BIL. Binding affinity and functional characterization of BIL were compared with those of several therapeutic insulins, insulin AspB10, and insulin-like growth factor 1 (IGF-1). BIL exhibited a markedly longer time to maximum concentration after subcutaneous injection, a greater area under the concentration-time curve, and a longer duration of action in the STZ-treated diabetic rat than insulin lispro. BIL exhibited reduced binding affinity and functional potency as compared with insulin lispro and demonstrated greater selectivity for the human insulin receptor (hIR) as compared with the human insulin-like growth factor 1 receptor. Furthermore, BIL showed a more rapid rate of dephosphorylation following maximal hIR stimulation, and reduced mitogenic potential in an IGF-1 receptor-dominant cellular model. PEGylation of insulin lispro with a 20-kDa PEG moiety at lysine B28 alters the absorption, clearance, distribution, and activity profile receptor, but does not alter its selectivity and full agonist receptor properties.

Pursuit of a perfect insulin

Insulin remains indispensable in the treatment of diabetes, but its use is hampered by its narrow therapeutic index. Although advances in peptide chemistry and recombinant DNA-based macromolecule synthesis have enabled the synthesis of structurally optimized insulin analogues, the growing epidemics of obesity and diabetes have emphasized the need for diabetes therapies that are more efficacious, safe and convenient. Accordingly, a broad set of drug candidates, targeting hyperglycaemia plus other disease abnormalities, is now progressing through the clinic. The development of an insulin therapy that is responsive to glucose concentration remains an ultimate goal, with initial prototypes now reaching the proof-of-concept stage. Simultaneously, the first alternatives to injectable delivery have progressed to registration.

Low within- and between-day variability in exposure to new insulin glargine 300 U/ml

AIMS

To characterize the variability in exposure and metabolic effect of insulin glargine 300 U/ml (Gla-300) at steady state in people with type 1 diabetes (T1DM).

METHODS

A total of 50 participants with T1DM underwent two 24-h euglycaemic clamps in steady-state conditions after six once-daily administrations of 0.4 U/kg Gla-300 in a double-blind, randomized, two-treatment, two-period, crossover clamp study. Participants were randomized to receive Gla-300 as a standard cartridge formulation in the first treatment period, and as a formulation with enhanced stability through polysorbate-20 addition in the second treatment period, or vice versa. This design allowed the assessment of bioequivalence between formulations and, subsequently, within- and between-day variability.

RESULTS

The cumulative exposure and effect of Gla-300 developed linearly over 24 h, and were evenly distributed across 6- and 12-h intervals. Diurnal fluctuation in exposure (within-day variability) was low; the peak-to-trough ratio of insulin concentration profiles was <2, and both the swing and peak-to-trough fluctuation were <1. Day-to-day reproducibility of exposure was high: the between-day within-subject coefficients of variation for total systemic exposure (area under the serum insulin glargine concentration time curve from time 0 to 24 h after dosing) and maximum insulin concentration were 17.4% [95% confidence interval (CI) 15-21] and 33.4% (95% CI 28-41), respectively. Reproducibility of the metabolic effect was lower than that of exposure.

CONCLUSIONS

Gla-300 provides predictable, evenly distributed 24-h coverage as a result of low fluctuation and high reproducibility in insulin exposure, and appears suitable for effective basal insulin use.

Investigation of the Physico-Chemical Properties that Enable Co-Formulation of Basal Insulin Degludec with Fast-Acting Insulin Aspart

Purpose

To study the self-association states of insulin degludec and insulin aspart alone and combined in pharmaceutical formulation and under conditions simulating the subcutaneous depot.

Methods

Formulations were made of 0.6 mM degludec at 3 and 5 Zn/6 insulin monomers, and 0.6 mM aspart (2 Zn/6 insulin monomers). Self-association was assessed using size-exclusion chromatography (SEC) monitored by UV and orthogonal reverse-phase chromatography.

Results

Simulating pharmaceutical formulation, degludec eluted as dihexamers, whereas aspart eluted as hexamers and monomers. Combining degludec at low zinc with aspart increased dihexamer content, indicating hybrid hexamer formation. At high zinc concentration, however, there was no evidence of this. Simulating the subcutaneous depot by removing preservative, degludec eluted as multihexamers and aspart as monomers. Aspart was incorporated into the multihexamer structures when combined with degludec at low zinc, but there was no such interaction with high-zinc degludec. SEC using progressively diluted concentrations of phenol and m-cresol showed that dissociation of aspart into monomers occurs before the formation of degludec multihexamers.

Conclusion

Insulins degludec and aspart can be combined without forming hybrid hexamers, but this combinability is dependent on zinc and preservative concentration, and requires that degludec is fully dihexameric before addition of aspart.

Evolution of insulin: from human to analog

The development of insulin analogs has made improved treatment of type 2 diabetes possible. In this article, structural alterations, pharmacokinetics and pharmacodynamics, clinical end points, and safety issues are reviewed for the currently available basal insulins, rapid-acting insulins, and premixes. The flatter activity profiles of insulin glargine and insulin detemir translate into good clinical efficacy with a lower risk of hypoglycemia relative to neutral protamine Hagedorn insulin. Weight gain is consistently lower with insulin detemir than with neutral protamine Hagedorn insulin. Insulin degludec, licensed in Europe and Japan but not yet in the United States, has a mean half-life of 25.4 hours, a duration of action of >42 hours, and low variability. In trials in type 2 diabetes, rates of nocturnal hypoglycemia were lower with insulin degludec than with insulin glargine, and more flexible; once-daily dose timing was shown to be possible. Insulin lispro, insulin aspart, and insulin glulisine are rapidly absorbed after injection and thus provide better coverage of the post-prandial glucose surge compared with human insulin. Trials and meta-analyses show that reductions in glycated hemoglobin are similar and control of postprandial glucose is better with the rapid-acting analogs versus human insulin. Convenience is greater for patients because the analogs can be injected just before a meal. In premix or biphasic insulins, a proportion of the rapid-acting analog is protaminated, providing both rapid-acting and intermediate-acting components in one formulation, thus reducing the number of injections required. Alterations to human insulin have resulted in improvements in safety, efficacy, tolerability, and convenience for patients.

Old and new basal insulin formulations: understanding pharmacodynamics is still relevant in clinical practice

Long-acting insulin analogues have been developed to mimic the physiology of basal insulin secretion more closely than human insulin formulations (Neutral Protamine Hagedorn, NPH). However, the clinical evidence in favour of analogues is still controversial. Although their major benefit as compared with NPH is a reduction in the hypoglycaemia risk, some cost/effectiveness analyses have not been favourable to analogues, largely because of their higher price. Nevertheless, these new formulations have conquered the insulin market. Human insulin represents currently no more than 20% of market share. Despite (in fact because of) the widespread use of insulin analogues it remains critical to analyse the pharmacodynamics (PD) of basal insulin formulations appropriately to interpret the results of clinical trials correctly. Importantly, these data may help physicians in tailoring insulin therapy to patients' individual needs and, additionally, when clinical evidence is not available, to optimize insulin treatment. For patients at low risk for/from hypoglycaemia, it might be acceptable and also cost-effective not to use long-acting insulin analogues as basal insulin replacement. Conversely, in patients with a higher degree of insulin deficiency and increased risk for hypoglycaemia, analogues are the best option due to their more physiological profile, as has been shown in PD and clinical studies. From this perspective optimizing basal insulin treatment, especially in type 2 diabetes patients who are less prone to hypoglycaemia, would be suitable making significant resources available for other relevant aspects of diabetes care.

Insulin degludec, a long-acting once-daily basal analogue for type 1 and type 2 diabetes mellitus

Here, we discuss certain practical issues related to use of insulin degludec, a new long-acting basal insulin analogue. Degludec provides uniform ("peakless") action that extends over more than 24 hours and is highly consistent from dose to dose. Like the 2 previously available basal analogues (detemir and glargine), degludec is expected to simplify dose adjustment and enable patients to reach their glycemic targets with reduced risk of hypoglycemia. Phase 3 clinical trials involving type 1 and type 2 diabetes have demonstrated that degludec was noninferior to glargine in allowing patients to reach a target glycated hemoglobin (A1C) of 7%, and nocturnal hypoglycemia occurred significantly less frequently with degludec. In addition, when dosing intervals vary substantially from day to day, degludec continues to be effective and to maintain a low rate of nocturnal hypoglycemia. Degludec thus has the potential to reduce risk of nocturnal hypoglycemia, to enhance the flexibility of the dosing schedule and to improve patient and caregiver confidence in the stability of glycemic control. A dedicated injector, the FlexTouch prefilled pen, containing degludec 200 units/mL, will be recommended for most patients with type 2 diabetes. Degludec will also be available as 100 units/mL cartridges, to be used in the NovoPen 4 by patients requiring smaller basal insulin doses, including most patients with type 1 diabetes.

When hypoglycemia is not obvious: diagnosing and treating under-recognized and undisclosed hypoglycemia

Hypoglycemia continues to be a significant problem for patients with diabetes. The incidence remains high but patients may also be under-reporting hypoglycemic events for various reasons, including hypoglycemia unawareness and deliberate non-reporting. This restricts the ability of healthcare professionals to manage treatment effectively. The aim of this article is to focus specifically on the issues associated with hypoglycemia unawareness and undisclosed hypoglycemia. The article provides general practice teams with an overview of these problems and, through patient narratives, suggests ways to mitigate them.