The continuing quest for better subcutaneously administered prandial insulins: a review of recent developments and potential clinical implications

Sociodemographic inequities and use of hybrid closed-loop systems associated with obesity in youth with type 1 diabetes

AIMS

This study aimed to describe changes over time in rates of overweight and obesity and to identify factors associated with obesity in youth with type 1 diabetes.

METHODS

We analyzed data from 7360 diabetes medical visits among 2242 youth with type 1 diabetes for ≥1 year followed at a pediatric, tertiary care, academic medical center between 2018 and 2023. Multivariable generalized estimating equations (GEE) analysis and conditional logistic regression (CLR), where each patient had both control (not obesity) and case (obesity) status, were conducted.

RESULTS

Adjusted annual percentages of patients with obesity increased from 13.8 % in 2018 to 18.2 % in 2023 (P = 0.006); rates of overweight did not differ significantly over time. In multivariable GEE analysis, public insurance (P = 0.026), lower Child Opportunity Index score (P = 0.027), and use of hybridclosed-loop (HCL) systems (P = 0.023) were associated with obesity. In CLR, use of continuous glucose monitor and HCL systems and the sum of their effects (P = 0.002) were associated with obesity.

CONCLUSIONS

This study revealed increasing rates of obesity in children with type 1 diabetes and identified sociodemographic and diabetes care-related factors associated with obesity, highlighting targets for intervention to decrease future risk of cardiovascular complications.

The Role of Ultra-Rapid-Acting Insulin Analogs in Diabetes: An Expert Consensus

Ultra-rapid-acting insulin analogs (URAA) are a further development and refinement of rapid-acting insulin analogs. Because of their adapted formulation, URAA provide an even faster pharmacokinetics and thus an accelerated onset of insulin action than conventional rapid-acting insulin analogs, allowing for a more physiologic delivery of exogenously applied insulin. Clinical trials have confirmed the superiority of URAA in controlling postprandial glucose excursions, with a safety profile that is comparable to the rapid-acting insulins. Consequently, many individuals with diabetes mellitus may benefit from URAA in terms of prandial glycemic control. Unfortunately, there are only few available recommendations from authoritative sources for use of URAA in clinical practice. Therefore, this expert consensus report aims to define populations of people with diabetes mellitus for whom URAA may be beneficial and to provide health care professionals with concrete, practical recommendations on how best to use URAA in this context.

Applying technologies to simplify strategies for exercise in type 1 diabetes

Challenges and fears related to managing glucose levels around planned and spontaneous exercise affect outcomes and quality of life in people living with type 1 diabetes. Advances in technology, including continuous glucose monitoring, open-loop insulin pump therapy and hybrid closed-loop (HCL) systems for exercise management in type 1 diabetes, address some of these challenges. In this review, three research or clinical experts, each living with type 1 diabetes, leverage published literature and clinical and personal experiences to translate research findings into simplified, patient-centred strategies. With an understanding of limitations in insulin pharmacokinetics, variable intra-individual responses to aerobic and anaerobic exercise, and the features of the technologies, six steps are proposed to guide clinicians in efficiently communicating simplified actions more effectively to individuals with type 1 diabetes. Fundamentally, the six steps centre on two aspects. First, regardless of insulin therapy type, and especially needed for spontaneous exercise, we provide an estimate of glucose disposal into active muscle meant to be consumed as extra carbohydrates for exercise ('ExCarbs'; a common example is 0.5 g/kg body mass per hour for adults and 1.0 g/kg body mass per hour for youth). Second, for planned exercise using open-loop pump therapy or HCL systems, we additionally recommend pre-emptive basal insulin reduction or using HCL exercise modes initiated 90 min (1-2 h) before the start of exercise until the end of exercise. Modifications for aerobic- and anaerobic-type exercise are discussed. The burden of pre-emptive basal insulin reductions and consumption of ExCarbs are the limitations of HCL systems, which may be overcome by future innovations but are unquestionably required for currently available systems.

Evidence for C-Peptide as a Validated Surrogate to Predict Clinical Benefits in Trials of Disease-Modifying Therapies for Type 1 Diabetes

Type 1 diabetes is a chronic autoimmune disease in which destruction of pancreatic β-cells causes life-threatening metabolic dysregulation. Numerous approaches are envisioned for new therapies, but limitations of current clinical outcome measures are significant disincentives to development efforts. C-peptide, a direct byproduct of proinsulin processing, is a quantitative biomarker of β-cell function that is not cleared by the liver and can be measured in the peripheral blood. Studies of quantitative measures of β-cell function have established a predictive relationship between stimulated C-peptide as a measure of β-cell function and clinical benefits. C-peptide levels at diagnosis are often high enough to afford glycemic control benefits associated with protection from end-organ complications of diabetes, and even lower levels offer protection from severe hypoglycemia in type 1 diabetes, as observed in large prospective cohort studies and interventional trials of islet transplantation. These observations support consideration of C-peptide not just as a biomarker of β-cell function but also as a specific, sensitive, feasible, and clinically meaningful outcome defining β-cell preservation or restoration for clinical trials of disease-modifying therapies. Regulatory acceptance of C-peptide as a validated surrogate for demonstration of efficacy would greatly facilitate development of disease-modifying therapies for type 1 diabetes.

ARTICLE HIGHLIGHTS

Insulin therapy in type 2 diabetes: Insights into clinical efficacy, patient-reported outcomes, and adherence challenges

Insulin therapy plays a crucial role in the management of type 2 diabetes as the disease progresses. Over the past century, insulin formulations have undergone significant modifications and bioengineering, resulting in a diverse range of available insulin products. These products show distinct pharmacokinetic and pharmacodynamic profiles. Consequently, various insulin regimens have em-erged for the management of type 2 diabetes, including premixed formulations and combinations of basal and bolus insulins. The utilization of different insulin regimens yields disparate clinical outcomes, adverse events, and, notably, patient-reported outcomes (PROs). PROs provide valuable insights from the patient's perspective, serving as a valuable mine of information for enhancing healthcare and informing clinical decisions. Adherence to insulin therapy, a critical patient-reported outcome, significantly affects clinical outcomes and is influenced by multiple factors. This review provides insights into the clinical effectiveness of various insulin preparations, PROs, and factors impacting insulin therapy adherence, with the aim of enhancing healthcare practices and informing clinical decisions for individuals with type 2 diabetes.

[Evolution of insulin therapy: past, present, future]

2021 marks the 100th anniversary of the discovery of insulin, an event that forever changed the lives of people with diabetes mellitus. At present patients around the world experience the miracle of insulin therapy every day. A disease that used to kill children and teenagers in 2 years in 1920 has become a disease that can be controlled with a possibility to lead a long productive life. Over the past century, the great discovery of Banting, Best and Collip has forever changed the world and saved millions of lives. This review is devoted to the history of the development of insulin and its further improvement: from the moment of discovery to the present days. Various generations of insulin are considered: from animals to modern ultrashort and basal analogues. The article ends with a brief review of current trends in the development of new delivery methods and the development of new insulin molecules. Over the past century, insulin therapy has come a long way, which has significantly improved the quality of life of our patients. But research is actively continuing, including in the field of alternative methods of insulin delivery, which are more convenient for the patient, as well as in the development of «smart» molecules that will have a glucose-dependent effect.

Key indices of glycaemic variability for application in diabetes clinical practice

Near normal glycaemic control in diabetes consists to target daily glucose fluctuations and quarterly HbA1c oscillations in addition to overall glucose exposure. Consequently, the prerequisite is to define simple, and mathematically undisputable key metrics for the short- and long-term variability in glucose homeostasis. As the standard deviations (SD) of either glucose or HbA1c are dependent on their means, the coefficient of variation (CV = SD/mean) should be applied instead as it that avoids the correlation between the SD and mean values. A CV glucose of 36% is the most appropriate threshold between those with stable versus labile glucose homeostasis. However, when near normal mean glucose concentrations are achieved a lower CV threshold of <27 % is necessary for reducing the risk for hypoglycaemia to a minimal rate. For the long-term variability in glucose homeostasis, a CVHbA1c < 5 % seems to be a relevant recommendation for preventing adverse clinical outcomes.

Understanding Biosimilar Insulins - Development, Manufacturing, and Clinical Trials

BACKGROUND

A wave of expiring patents for first-generation insulin analogues has created opportunities in the global insulin market for highly similar versions of these products, biosimilar insulins. Biologics are generally large, complex molecules produced through biotechnology in a living system, such as a microorganism, plant cell, or animal cell. Since manufacturing processes of biologics vary, biosimilars cannot be exact copies of their reference product but must exhibit a high degree of functional and structural similarity. Biosimilarity is proven by analytical approaches in comparative assessments, preclinical cell-based and animal studies, as well as clinical studies in humans facilitating the accumulation of evidence across all assessments. The approval of biosimilars follows detailed regulatory pathways derived from those of their reference products and established by agencies such as the European Medicines Agency and the US Food and Drug Administration. Regulatory authorities impose requirements to ensure that biosimilars meet high standards of quality, safety, and efficacy and are highly similar to their reference product.

PURPOSE

This review aims to aid clinical understanding of the high standards of development, manufacturing, and regulation of biosimilar insulins.

METHODS

Recent relevant studies indexed by PubMed and regulatory documents were included.

CONCLUSIONS

Driven by price competition, the emergence of biosimilar insulins may help expand global access to current insulin analogues. To maximize the impact of the advantage for falling retail costs of biosimilar insulins compared with that of reference insulins, healthcare professionals and insulin users must gain further awareness and confidence.

Accelerated absorption of regular insulin administered via a vascularizing permeable microchamber implanted subcutaneously in diabetic Rattus norvegicus

In Type 1 diabetes patients, even ultra-rapid acting insulins injected subcutaneously reach peak concentrations in 45 minutes or longer. The lag time between dosing and peak concentration, as well as intra- and inter-subject variability, render prandial glucose control and dose consistency difficult. We postulated that insulin absorption from subcutaneously implantable vascularizing microchambers would be significantly faster than conventional subcutaneous injection. Male athymic nude R. norvegicus rendered diabetic with streptozotocin were implanted with vascularizing microchambers (single chamber; 1.5 cm2 surface area per side; nominal volume, 22.5 μl). Plasma insulin was assayed after a single dose (1.5 U/kg) of diluted insulin human (Humulin®R U-100), injected subcutaneously or via microchamber. Microchambers were also implanted in additional animals and retrieved at intervals for histologic assessment of vascularity. Following conventional subcutaneous injection, the mean peak insulin concentration was 22.7 (SD 14.2) minutes. By contrast, when identical doses of insulin were injected via subcutaneous microchamber 28 days after implantation, the mean peak insulin time was shortened to 7.50 (SD 4.52) minutes. Peak insulin concentrations were similar by either route; however, inter-subject variability was reduced when insulin was administered via microchamber. Histologic examination of tissue surrounding microchambers showed mature vascularization on days 21 and 40 post-implantation. Implantable vascularizing microchambers of similar design may prove clinically useful for insulin dosing, either intermittently by needle, or continuously by pump including in "closed loop" systems, such as the artificial pancreas.

A new proposal for a second insulin bolus to optimize postprandial glucose profile in adolescents with type 1 diabetes

AIMS

To evaluate whether a second insulin bolus, calculated with a new approach, could improve postprandial glucose (PPG) after the intake of real-life high-fat (HF) and high-protein (HP) mixed meals.

METHODS

Fifteen adolescents with T1D treated with non-automated insulin pumps and CGM were enrolled. Patients received standard, HF and HP mixed meals treated with one pre-meal insulin bolus; based on differences in PPG between standard, HF and HP meals, correction boluses were calculated (30% and 60% of pre-meal bolus for HF and HP meals, respectively). Then patients received the same HF or HP meal treated with pre-meal bolus plus second insulin bolus after 3 h. Differences between postprandial variables after HF and HP meals treated with one or two insulin boluses were assessed by paired Student's t-test.

RESULTS

Treating HF and HP meals with two insulin boluses significantly reduced the postprandial BG-AUC (21% and 26% respectively, p < 0.05), increased %TIR (from 52.5 to 78.3% for HF meal; from 32.7 to 57.1% for HP meal; p < 0.01), and reduced mean BG and %TAR (p < 0.01), with no differences in %TBR.

CONCLUSIONS

The new way to calculate and administer correction boluses 3 h after HF and HP meals is effective and safe in reducing PPG and the hypoglycemia risk.

Targeting pancreatic β cells for diabetes treatment

Insulin is a life-saving drug for patients with type 1 diabetes; however, even today, no pharmacotherapy can prevent the loss or dysfunction of pancreatic insulin-producing β cells to stop or reverse disease progression. Thus, pancreatic β cells have been a main focus for cell-replacement and regenerative therapies as a curative treatment for diabetes. In this Review, we highlight recent advances toward the development of diabetes therapies that target β cells to enhance proliferation, redifferentiation and protection from cell death and/or enable selective killing of senescent β cells. We describe currently available therapies and their mode of action, as well as insufficiencies of glucagon-like peptide 1 (GLP-1) and insulin therapies. We discuss and summarize data collected over the last decades that support the notion that pharmacological targeting of β cell insulin signalling might protect and/or regenerate β cells as an improved treatment of patients with diabetes.

Insulin: evolution of insulin formulations and their application in clinical practice over 100 years

The first preparation of insulin extracted from a pancreas and made suitable for use in humans after purification was achieved 100 years ago in Toronto, an epoch-making achievement, which has ultimately provided a life-giving treatment for millions of people worldwide. The earliest animal-derived formulations were short-acting and contained many impurities that caused adverse reactions, thereby limiting their therapeutic potential. However, since then, insulin production and purification improved with enhanced technologies, along with a full understanding of the insulin molecule structure. The availability of radio-immunoassays contributed to the unravelling of the physiology of glucose homeostasis, ultimately leading to the adoption of rational models of insulin replacement. The introduction of recombinant DNA technologies has since resulted in the era of both rapid- and long-acting human insulin analogues administered via the subcutaneous route which better mimic the physiology of insulin secretion, leading to the modern basal-bolus regimen. These advances, in combination with improved education and technologies for glucose monitoring, enable people with diabetes to better meet individual glycaemic goals with a lower risk of hypoglycaemia. While the prevalence of diabetes continues to rise globally, it is important to recognise the scientific endeavour that has led to insulin remaining the cornerstone of diabetes management, on the centenary of its first successful use in humans.

Faster Insulin Aspart for Continuous Subcutaneous Insulin Infusion: Is It Worth It?

Introduction

Faster insulin aspart (fASP) is the new formulation of insulin aspart (ASP) with a left-shifted pharmacokinetic profile, allowing better control of early postprandial hyperglycemia and a reduction in the risk of late post-meal hypoglycemia. However, it can be associated with more frequent infusion set changes. The purpose of this study is to evaluate efficacy and safety one, three, and six months after starting fASP in continuous subcutaneous insulin infusion (CSII) systems.

Methods

This is a retrospective study that included adults with type 1 diabetes mellitus, users of CSII ≥3 months, who started fASP. Exclusion criteria included less than one month of follow-up after the intervention, concomitant initiation of pharmacological therapy, pre-conception period, and non-use of continuous glucose monitoring.

Results

A total of 77 individuals were included, of which 52 (67.5%) were female, aged 39.87 ± 13.10 years, with a mean time under CSII of 7.30 ± 3.58 years and a median follow-up time after transition to fASP of six months. There was a trend to a global glycemic control improvement at six months after starting fASP: numeric increase in time in range (56.40 ± 12.62% vs 60.15 ± 13.53%, p=0.148), reduction in time above range (37.76 ± 13.05% vs 34.67 ± 14.94%, p=0.557), time below range (6.00 (5.00)% vs 4.50 (5.25)%, p=0.122), and mean glucose (174.29 ± 25.14 mg/dL vs 167.00 ± 25.30 mg/dL, p=0.207). There was a reduction in body mass index (BMI) at six months after switching to fASP (25.08 (4.59) kg/m² vs 24.45 (3.05) kg/m², p=0.010), despite the absence of a significant variation in total daily insulin. Adverse event and discontinuation rates were 7.8% and 6.5%, respectively, with no documented episodes of diabetic ketoacidosis or severe hypoglycemia.

Conclusions

fASP proved to be a safe and effective therapeutic option in CSII systems associated with a significant BMI reduction, aspects that might justify its preference.

Photoacoustic imaging reveals mechanisms of rapid-acting insulin formulations dynamics at the injection site

OBJECTIVE

Ultra-rapid insulin formulations control postprandial hyperglycemia; however, inadequate understanding of injection site absorption mechanisms is limiting further advancement. We used photoacoustic imaging to investigate the injection site dynamics of dye-labeled insulin lispro in the Humalog® and Lyumjev® formulations using the murine ear cutaneous model and correlated it with results from unlabeled insulin lispro in pig subcutaneous injection model.

METHODS

We employed dual-wavelength optical-resolution photoacoustic microscopy to study the absorption and diffusion of the near-infrared dye-labeled insulin lispro in the Humalog and Lyumjev formulations in mouse ears. We mathematically modeled the experimental data to calculate the absorption rate constants and diffusion coefficients. We studied the pharmacokinetics of the unlabeled insulin lispro in both the Humalog and Lyumjev formulations as well as a formulation lacking both the zinc and phenolic preservative in pigs. The association state of insulin lispro in each of the formulations was characterized using SV-AUC and NMR spectroscopy.

RESULTS

Through experiments using murine and swine models, we show that the hexamer dissociation rate of insulin lispro is not the absorption rate-limiting step. We demonstrated that the excipients in the Lyumjev formulation produce local tissue expansion and speed both insulin diffusion and microvascular absorption. We also show that the diffusion of insulin lispro at the injection site drives its initial absorption; however, the rate at which the insulin lispro crosses the blood vessels is its overall absorption rate-limiting step.

CONCLUSIONS

This study provides insights into injection site dynamics of insulin lispro and the impact of formulation excipients. It also demonstrates photoacoustic microscopy as a promising tool for studying protein therapeutics. The results from this study address critical questions around the subcutaneous behavior of insulin lispro and the formulation excipients, which could be useful to make faster and better controlled insulin formulations in the future.

Glycemic control after switching to faster aspart in adults with type 1 diabetes

AIMS

Post-prandial hyperglycemia remains an unmet need in the management of type 1 diabetes (T1D). In randomized trials, faster insulin aspart (FIA) showed modest but significant reductions of glycemic spikes after meals. Whether such benefit is evident in routine clinical practice is unclear.

METHODS

We analyzed data of patients with T1D at the time they switched from a prior bolus insulin to FIA and at the first available follow-up. The primary endpoint was the change in the time spent in hyperglycemia > 250 mg/dl during daytime from flash glucose monitoring (FGM). Secondary outcomes included the change in HbA1c, body weight, insulin dose and other FGM metrics.

RESULTS

We included 117 patients with T1D on multiple daily injections who switched to FIA, 57 of whom had data from FGM. Patients were 41-year-old, 51.3% men, with 19.3 years diabetes duration and a baseline HbA1c of 7.7% (60 mmol/mol). Mean observation time was 4.3 months. After switching to FIA, HbA1c declined by 0.1% (1 mmol/mol) only in patients with baseline HbA1c > 7.0% (53 mmol/mol). Time spent in hyperglycemia > 250 mg/dl during daytime was significantly reduced from 14.8 to 11.9% (p = 0.006). Time in range improved from 48.3 to 51.0% (p = 0.028). Results were consistent across various patient characteristics.

CONCLUSIONS

Under routine care, patients with T1D who switched to FIA experienced a reduction in the time spent in hyperglycemia > 250 mg/dl during daytime and an increase in time in range. These improvements may be due to better control of post-prandial hyperglycemia, as observed in trials.

New Horizons: Next-Generation Insulin Analogues: Structural Principles and Clinical Goals

Design of "first-generation" insulin analogues over the past 3 decades has provided pharmaceutical formulations with tailored pharmacokinetic (PK) and pharmacodynamic (PD) properties. Application of a molecular tool kit-integrating protein sequence, chemical modification, and formulation-has thus led to improved prandial and basal formulations for the treatment of diabetes mellitus. Although PK/PD changes were modest in relation to prior formulations of human and animal insulins, significant clinical advantages in efficacy (mean glycemia) and safety (rates of hypoglycemia) were obtained. Continuing innovation is providing further improvements to achieve ultrarapid and ultrabasal analogue formulations in an effort to reduce glycemic variability and optimize time in range. Beyond such PK/PD metrics, next-generation insulin analogues seek to exploit therapeutic mechanisms: glucose-responsive ("smart") analogues, pathway-specific ("biased") analogues, and organ-targeted analogues. Smart insulin analogues and delivery systems promise to mitigate hypoglycemic risk, a critical barrier to glycemic control, whereas biased and organ-targeted insulin analogues may better recapitulate physiologic hormonal regulation. In each therapeutic class considerations of cost and stability will affect use and global distribution. This review highlights structural principles underlying next-generation design efforts, their respective biological rationale, and potential clinical applications.

Insulin discovery: A pivotal point in medical history

The discovery of insulin in 1921 - due to the efforts of the Canadian research team based in Toronto - has been a landmark achievement in the history of medicine. Lives of people with diabetes were changed forever, considering that in the pre-insulin era this was a deadly condition. Insulin, right after its discovery, became the first hormone to be purified for human use, the first to be unraveled in its amino acid sequence and to be synthetized by DNA-recombinant technique, the first to be modified in its amino acid sequence to modify its duration of action. As such the discovery of insulin represents a pivotal point in medical history. Since the early days of its production, insulin has been improved in its pharmacokinetic and pharmacodynamic properties in the attempt to faithfully reproduce diurnal physiologic plasma insulin fluctuations. The evolution of insulin molecule has been paralleled by evolution in the way the hormone is administered. Once-weekly insulins will be available soon, and glucose-responsive "smart" insulins start showing their potential in early clinical studies. The first century of insulin as therapy was marked by relentless search for better formulations, a search that has not stopped yet. New technologies may have, indeed, the potential to provide further improvement of safety and efficacy of insulin therapy and, therefore, contribute to improvement of the quality of life of people with diabetes.

Insulin Centennial: Milestones influencing the development of insulin preparations since 1922

During 1921 to 1922, a team effort by Banting, Macleod, Collip and Best isolated and purified insulin and demonstrated its life-giving properties, giving rise to the birth of insulin therapy. In the early years (1922-1950), priorities revolved around the manufacture of insulin to meet demand, improving purity to avoid allergic reactions, establishing insulin standards and increasing its duration of action to avoid multiple daily injections. Shortly after the emergence of insulin, Joslin and Allen advocated the need to achieve and maintain good glycaemic control to realize its full potential. Although this view was opposed by some during a dark period in the history of insulin, it was subsequently endorsed some 60 years later endorsed by the Diabetes Control and Complications Trial and United Kingdom Prospective Diabetes Study. Major scientific advances by the Nobel Laureates Sanger, Hodgkin, Yalow and Gilbert and also by Steiner have revolutionized the understanding of diabetes and facilitated major advances in insulin therapy. The more recent advent of recombinant technology over the last 40 years has provided the potential for unlimited source of insulin, and the ability to generate various insulin 'analogues', in an attempt to better replicate normal insulin secretory patterns. The emerging biosimilars now provide the opportunity to improve availability at a lower cost.

One-hundred year evolution of prandial insulin preparations: From animal pancreas extracts to rapid-acting analogs

The first insulin preparation injected in humans in 1922 was short-acting, extracted from animal pancreas, contaminated by impurities. Ever since the insulin extracted from animal pancreas has been continuously purified, until an unlimited synthesis of regular human insulin (RHI) became possible in the '80s using the recombinant-DNA (rDNA) technique. The rDNA technique then led to the designer insulins (analogs) in the early '90s. Rapid-acting insulin analogs were developed to accelerate the slow subcutaneous (sc) absorption of RHI, thus lowering the 2-h post-prandial plasma glucose (PP-PG) and risk for late hypoglycemia as comparing with RHI. The first rapid-acting analog was lispro (in 1996), soon followed by aspart and glulisine. Rapid-acting analogs are more convenient than RHI: they improve early PP-PG, and 24-h PG and A1C as long as basal insulin is also optimized; they lower the risk of late PP hypoglycemia and they allow a shorter time-interval between injection and meal. Today rapid-acting analogs are the gold standard prandial insulins. Recently, even faster analogs have become available (faster aspart, ultra-rapid lispro) or are being studied (Biochaperone lispro), making additional gains in lowering PP-PG. Rapid-acting analogs are recommended in all those with type 1 and type 2 diabetes who need prandial insulin replacement.

One hundred years of insulin therapy

At the time of its first clinical application 100 years ago, insulin was presented as the cure for people with diabetes mellitus. That transpired to be an overstatement, yet insulin has proven to be the lifesaver for people with type 1 diabetes mellitus and an essential therapy for many with type 2 diabetes mellitus or other forms of diabetes mellitus. Since its discovery, insulin (a molecule of only 51 amino acids) has been the subject of pharmaceutical research and development that has paved the way for other protein-based therapies. From purified animal-extracted insulin and human insulin produced by genetically modified organisms to a spectrum of insulin analogues, pharmaceutical laboratories have strived to tailor the preparations to the needs of patients. Nonetheless, overall glycaemic control often remains poor as exogenous insulin is still not able to mimic the physiological insulin profile. Circumventing subcutaneous administration and the design of analogues with profiles that mimic that of physiological insulin are ongoing areas of research. Novel concepts, such as once-weekly insulins or glucose-dependent and oral insulins, are on the horizon but their real-world effectiveness still needs to be proven. Until a true cure for type 1 diabetes mellitus is found and the therapeutic arsenal for other forms of diabetes mellitus is expanded, insulin will remain central in the treatment of many people living with diabetes mellitus.

Future directions in insulin therapy

Insulin therapy has a long history at the cutting edge of technological development through purification, extended-action, molecular chemistry, and devices, and in support technologies including self-measurement and patient education. But unmet needs remain large. Today's therapy cannot deliver minute-to-minute control of glucose levels, and cannot imitate the reflex/incretin driven physiological insulin delivery at mealtimes. Further it depends on a raft of devices for administration several times a day, devices liked for their functionality, but disliked as an intrusive reminder of the condition, several times a day. Approaches to overcoming these barriers include closed-loop systems and further modification of insulin formulations, but are limited by fundamental underlying difficulties. While clinical studies of oral insulin are in progress, the barriers to success look daunting. Development of small-molecule approaches (insulin-mimetic tablets) appears to have stalled, while concepts for glucose-responsive insulin as yet fail to deliver the necessary insulin-to-glucose gradient. Gene therapy, feasible in animals in preliminary studies, is not capable of providing feedback control. Transplantation of cultured islets and islet B-cells from stem cells thus looks to the be the best long-term prospect for insulin delivery in terms of overcoming the above barriers, but is a true biotechnological tour-de-force which will take time to mature.

Insulin therapy development beyond 100 years

The first insulin preparation capable of consistently lowering blood glucose was developed in 1921. But 100 years later, blood glucose control with insulin in people with diabetes is nearly universally suboptimal, with essentially the same molecule still delivered by the same inappropriate subcutaneous injection route. Bypassing this route with oral administration appears to have become technologically feasible, accelerating over the past 50 years, either with packaged insulin peptides or by chemical insulin mimetics. Some of the problems of prospective unregulated absorption of insulin into the circulation from subcutaneous depots might be overcome with glucose-responsive insulins. Approaches to these problems could be modification of the peptide by adducts, or the use of nanoparticles or insulin patches, which deliver insulin according to glucose concentration. Some attention has been paid to targeting insulin preferentially to different organs, either by molecular engineering of insulin, or with adducts. But all these approaches still have problems in even beginning to match the responsiveness of physiological insulin delivery to metabolic requirements, both prandially and basally. As would be expected, for all these technically complex approaches, many examples of abandoned development can be found. Meanwhile, it is becoming possible to change the duration of action of subcutaneous injected insulin analogues to act even more rapidly for meals, and towards weekly insulin for basal administration. The state of the art of all these approaches, and the barriers to success, are reviewed here.

Ultra-rapid-acting insulins for adults with diabetes: A systematic review and meta-analysis

We performed a systematic review and meta-analysis of randomized controlled trials to assess the efficacy and safety of the novel, ultra-rapid-acting insulins aspart and lispro in adults with type 1 or type 2 diabetes. Our primary outcome was change in HbA1c from baseline. We additionally assessed eight efficacy and six safety endpoints. We calculated weighted mean differences (WMD) for continuous outcomes and odds ratios (ORs) for dichotomous outcomes, alongside 95% confidence intervals (CIs). We additionally assessed statistical heterogeneity among studies with the I² statistic, considering values greater than 60% as indicative of substantial heterogeneity. Nine studies comprising 5931 patients were included in the systematic review; eight active-controlled studies could be synthesized in terms of a meta-analysis. Treatment with ultra-rapid-acting insulins had a similar effect on change in HbA1c compared with rapid-acting insulins (WMD -0.02%, 95% CI -0.08 to 0.05, I²  = 61% for patients with type 1 diabetes and -0.02%, 95% CI -0.09 to 0.04, I²  = 19% for patients with type 2 diabetes). Similarly, no difference was evident in terms of change in fasting plasma glucose, self-measured plasma glucose, body weight, basal or bolus insulin dose, incidence of serious adverse events and hypoglycaemia. Compared with rapid-acting insulins, ultra-rapid-acting insulins reduced 1- and 2-hour postprandial glucose (PPG) increment based on a liquid meal test, both in patients with type 1 and type 2 diabetes (WMD -0.94 mmol/L, 95% CI -1.17 to -0.72, I²  = 0% and -0.56 mmol/L, 95% CI -0.79 to -0.32, I²  = 0%, respectively, for change in 1-hour PPG increment). In conclusion, ultra-rapid-acting insulins were as efficacious and safe as rapid-acting insulins, showing a favourable effect solely on PPG control.

Structural principles of insulin formulation and analog design: A century of innovation

BACKGROUND

The discovery of insulin in 1921 and its near-immediate clinical use initiated a century of innovation. Advances extended across a broad front, from the stabilization of animal insulin formulations to the frontiers of synthetic peptide chemistry, and in turn, from the advent of recombinant DNA manufacturing to structure-based protein analog design. In each case, a creative interplay was observed between pharmaceutical applications and then-emerging principles of protein science; indeed, translational objectives contributed to a growing molecular understanding of protein structure, aggregation and misfolding.

SCOPE OF REVIEW

Pioneering crystallographic analyses-beginning with Hodgkin's solving of the 2-Zn insulin hexamer-elucidated general features of protein self-assembly, including zinc coordination and the allosteric transmission of conformational change. Crystallization of insulin was exploited both as a step in manufacturing and as a means of obtaining protracted action. Forty years ago, the confluence of recombinant human insulin with techniques for site-directed mutagenesis initiated the present era of insulin analogs. Variant or modified insulins were developed that exhibit improved prandial or basal pharmacokinetic (PK) properties. Encouraged by clinical trials demonstrating the long-term importance of glycemic control, regimens based on such analogs sought to resemble daily patterns of endogenous β-cell secretion more closely, ideally with reduced risk of hypoglycemia.

MAJOR CONCLUSIONS

Next-generation insulin analog design seeks to explore new frontiers, including glucose-responsive insulins, organ-selective analogs and biased agonists tailored to address yet-unmet clinical needs. In the coming decade, we envision ever more powerful scientific synergies at the interface of structural biology, molecular physiology and therapeutics.

Carbohydrate restriction for diabetes: rediscovering centuries-old wisdom

Carbohydrate restriction, used since the 1700s to prolong survival in people with diabetes, fell out of favor after the discovery of insulin. Despite costly pharmacological and technological developments in the last few decades, current therapies do not achieve optimal outcomes, and most people with diabetes remain at high risk for micro- and macrovascular complications. Recently, low-carbohydrate diets have regained popularity, with preliminary evidence of benefit for body weight, postprandial hyperglycemia, hyperinsulinemia, and other cardiometabolic risk factors in type 2 diabetes and, with more limited data, in type 1 diabetes. High-quality, long-term trials are needed to assess safety concerns and determine whether this old dietary approach might help people with diabetes attain clinical targets more effectively, and at a lower cost, than conventional treatment.

Dual-hormone artificial pancreas for management of type 1 diabetes: Recent progress and future directions

Over the last few years, technological advances have led to tremendous improvement in the management of type 1 diabetes (T1D). Artificial pancreas systems have been shown to improve glucose control compared with conventional insulin pump therapy. However, clinically significant hypoglycemic and hyperglycemic episodes still occur with the artificial pancreas. Postprandial glucose excursions and exercise-induced hypoglycemia represent major hurdles in improving glucose control and glucose variability in many patients with T1D. In this regard, dual-hormone artificial pancreas systems delivering other hormones in addition to insulin (glucagon or amylin) may better reproduce the physiology of the endocrine pancreas and have been suggested as an alternative tool to overcome these limitations in clinical practice. In addition, novel ultra-rapid-acting insulin analogs with a more physiological time-action profile are currently under investigation for use in artificial pancreas devices, aiming to address the unmet need for further improvements in postprandial glucose control. This review article aims to discuss the current progress and future outlook in the development of novel ultra-rapid insulin analogs and dual-hormone closed-loop systems, which offer the next steps to fully closing the loop in the artificial pancreas.

Glucagon as a Therapeutic Approach to Severe Hypoglycemia: After 100 Years, Is It Still the Antidote of Insulin?

Hypoglycemia represents a dark and tormented side of diabetes mellitus therapy. Patients treated with insulin or drug inducing hypoglycemia, consider hypoglycemia as a harmful element, which leads to their resistance and lack of acceptance of the pathology and relative therapies. Severe hypoglycemia, in itself, is a risk for patients and relatives. The possibility to have novel strategies and scientific knowledge concerning hypoglycemia could represent an enormous benefit. Novel available glucagon formulations, even now, allow clinicians to deal with hypoglycemia differently with respect to past years. Novel scientific evidence leads to advances concerning physiopathological mechanisms that regulated glycemic homeostasis. In this review, we will try to show some of the important aspects of this field.

Type 1 diabetes glycemic management: Insulin therapy, glucose monitoring, and automation

Despite innovations in insulin therapy since its discovery, most patients living with type 1 diabetes do not achieve sufficient glycemic control to prevent complications, and they experience hypoglycemia, weight gain, and major self-care burden. Promising pharmacological advances in insulin therapy include the refinement of extremely rapid insulin analogs, alternate insulin-delivery routes, liver-selective insulins, add-on drugs that enhance insulin effect, and glucose-responsive insulin molecules. The greatest future impact will come from combining these pharmacological solutions with existing automated insulin delivery methods that integrate insulin pumps and glucose sensors. These systems will use algorithms enhanced by machine learning, supplemented by technologies that include activity monitors and sensors for other key metabolites such as ketones. The future challenges facing clinicians and researchers will be those of access and broad clinical implementation.

Pharmacological Management of Diabetes Mellitus: A Century of Expert Opinions in Cecil Textbook of Medicine

BACKGROUND

Drug therapy for diabetes mellitus (DM) has had a significant impact on quality of life and work potential of affected persons and has contributed to a remarkable decrease in the frequency and severity of complications, hospitalizations, and mortality. The current approach is the result of incremental progress in using technological advances to increase the safety and effectiveness of insulin therapy and the introduction of new molecules as oral and injectable antidiabetic drugs.

STUDY QUESTION

What are the milestones of the changes in the expert approach to the pharmacological management of DM in the past century?

STUDY DESIGN

To determine the changes in the experts' approach to the management of DM, as presented in a widely used textbook in the United States.

DATA SOURCES

The chapters on describing the management of DM in the 26 editions of Cecil Textbook of Medicine published from 1927 to 2020.

RESULTS

In 1927, DM was treated with insulin extracted from the pancreas of large animals (cattle, hogs, and sheep) and purified with alcohol to prevent the tissues' proteolytic action on the hormone. The therapeutic milestones in DM marked 2 avenues for innovation. The first created advances in insulin therapy, starting with processes that led to the production of crystalline insulin and protamine zinc insulin (1937), synthetic human insulin (1996), and prandial (2000) and basal (2004) insulin analogues. The second was an effort to develop and introduce in clinical practice in the United States oral antidiabetic drugs, starting with tolbutamide, a sulfonylurea (1955), followed by metformin, a biguanide (1996), thiazolidinediones, alpha-glucosidase inhibitors, and benzoic acid derivatives (2000), dipeptidyl peptidase-4 inhibitors and glucagon-like peptide 1 receptor agonists (2008), and sodium glucose cotransporter 2 inhibitors (2020). A latent period of 40 years between significant advances was likely because of searches for new technologies (eg, recombinant DNA for the production of synthetic insulin and analogues) and, at least in part, to the impact of the controversial University Group Diabetes Project on the development and acceptance of oral antidiabetic drugs.

CONCLUSIONS

The pharmacological management of DM has progressed unevenly, with a long latency period in the second half of the last century followed by highly encouraging advances in the first 2 decades of the 21st century. In chronological order, the major advances were synthetic insulins obtained through DNA recombinant technology, adoption of metformin as first line therapy, and introduction of antidiabetic medication classes that also promote weight reduction and cardiovascular health.

The promising future of insulin therapy in diabetes mellitus

The first therapeutic use of insulin by Frederick Banting and Charles Best in 1921 revolutionized the management of type 1 diabetes and considerably changed the lives of many patients with other types of diabetes. In the past 100 years, significant pharmacological advances took place in the field of insulin therapy, bringing closer the goal of optimal glycemic control along with decreased diabetes-related complications. Despite these developments, several challenges remain, such as increasing treatment flexibility, reducing iatrogenic hypoglycemia, and optimizing patient quality of life. Ongoing innovations in insulin therapy (e.g., new insulin analogs, alternative routes of insulin administration, and closed-loop technology) endeavor to overcome these hurdles and change the landscape of diabetes mellitus management. This report highlights recent advances made in the field of insulin therapy and discusses future perspectives.

Minimising hypoglycaemia in the real world: the challenge of insulin

Insulin therapy has been a life saver for people with type 1 diabetes and has been an essential tool in the therapy of people with type 2 diabetes, but the risk for hypoglycaemia has been a major hurdle to achieving good glycaemic control for most. Insulin analogues, the availability of novel technologies for the administration of insulin, like insulin pumps, and, in particular, tools to measure glucose levels, evolving from capillary measurements to continuous glucose monitoring, have revolutionised the way in which people living with diabetes use insulin. Novel insulin concepts, like once-weekly or oral insulin administration, will have to demonstrate safety on the side of hypoglycaemia before they will be able to move into the clinic.

The physiological basis of insulin therapy in people with diabetes mellitus

Insulin therapy has been in use now for 100 years, but only recently insulin replacement has been based on physiology. The pancreas secretes insulin at continuously variable rates, finely regulated by sensitive arterial glucose sensing. Pancreatic insulin is delivered directlyin the portal blood to insulinize preferentially the liver. In the fasting state, insulin is secreted at a low rate to modulate hepatic glucose output. After liver extraction (50%), insulin concentrations in peripheral plasma are 2.4-4 times lower than in portal, but still efficacious to restrain lipolysis. In the prandial condition, insulin is secreted rapidly in large amounts to increase portal and peripheral concentrations to peaks 10-20 times greater vs the values of fasting within 30-40 min from meal ingestion. The prandial portal hyperinsulinemia fully suppresses hepatic glucose production while peripheral hyperinsulinemia increases glucose utilization, thus limitating the post-prandial plasma glucose elevation. Physiology of insulin indicates that insulin should be replaced in people with diabetes mimicking the pancreas, i.e. in a basal-bolus mode, for fasting and prandial state, respectively. Despite the presently ongoing limitations (subcutaneous and peripheral rather than portal and intravenous insulin delivery), basal-bolus insulin allows people with diabetes to achieve A1c in the range with minimal risk of hypoglycaemia, to prevent vascular complications and to ensure good quality of life.

Diabetes education in pediatrics: How to survive diabetes

Diabetes mellitus is the most common abnormal carbohydrate metabolism disorder affecting millions of people worldwide. It is characterized by hyperglycemia as a result of ß-cell destruction or dysfunction by both genetic and environmental factors. Over time chronic hyperglycemia leads to microvascular (i.e., retinopathy, nephropathy and neuropathy) and macrovascular (i.e., ischemic heart disease, peripheral vascular disease, and cerebrovascular disease) complications of diabetes. Diabetes complication trials showed the importance of achieving near-normal glycemic control to prevent and/or reduce diabetes-related morbidity and mortality. There is a staggering rate of increased incidence of diabetes in youth, raising concerns for future generations' health, quality of life and its enormous economic burden. Despite advancements in the technology, diabetes management remains cumbersome. Training individuals with diabetes to gain life-long survival skills requires a comprehensive and ongoing diabetes education by a multidisciplinary team. Diabetes education and training start at the time of diagnosis of diabetes and should be continuous throughout the course of disease. The goal is to empower the individuals and families to gain diabetes self-management skills. Diabetes education must be individualized depending on the individual's age, education, family dynamics, and support. In this article, we review the history of diabetes, etiopathogenesis and clinical presentation of both type 1 and type 2 diabetes in children as well as adolescents. We then focus on diabetes management with education methods and materials.

Pharmacokinetics and Pharmacodynamics of Three Different Formulations of Insulin Aspart: A Randomized, Double-Blind, Crossover Study in Men With Type 1 Diabetes

OBJECTIVE

To investigate the pharmacokinetic and pharmacodynamic properties and safety of a novel formulation of insulin aspart (AT247) versus two currently marketed insulin aspart formulations (NovoRapid [IAsp] and Fiasp [faster IAsp]).

RESEARCH DESIGN AND METHODS

This single-center, randomized, double-blind, three-period, crossover study was conducted in 19 men with type 1 diabetes, receiving single dosing of trial products (0.3 units/kg) in a random order on three visits. Pharmacokinetics and pharmacodynamics were assessed during a euglycemic clamp lasting up to 8 h.

RESULTS

Onset of insulin appearance was earlier for AT247 compared with IAsp (-12 min [95% CI -14; -8], P = 0.0004) and faster IAsp (-2 min [-5; -2], P = 0.0003). Onset of action was accelerated compared with IAsp (-23 min [-37; -15], P = 0.0004) and faster IAsp (-9 min [-11; -3], P = 0.0006). Within the first 60 min, a higher exposure was observed for AT247 compared with IAsp by the area under the curve (AUC) glucose infusion rate (GIR) from 0 to 60 min (AUC_Asp0-60min: treatment ratio vs. IAsp 2.3 [1.9; 2.9] vs. faster IAsp 1.5 [1.3; 1.8]), which was underpinned by a greater early glucose-lowering effect (AUC_GIR,0-60min: treatment ratio vs. IAsp 2.8 [2.0; 5.5] vs. faster IAsp 1.7 [1.3; 2.3]). Furthermore, an earlier offset of exposure was observed for AT247 compared with IAsp (-32 min [-58; -15], P = 0.0015) and faster IAsp (-27 min [-85; -15], P = 0.0017), while duration of the glucose-lowering effect, measured by time to late half-maximum effect, did not differ significantly.

CONCLUSIONS

AT247 exhibited an earlier insulin appearance, exposure, and offset, with corresponding enhanced early glucose-lowering effect compared with IAsp and faster IAsp. It therefore represents a promising candidate in the pursuit for second-generation prandial insulin analogs to improve postprandial glycemic control.

Advances in newer basal and bolus insulins: impact on type 1 diabetes

PURPOSE OF REVIEW

Insulin administration is vitally important to maintain a good glycaemic control in people with type 1 diabetes mellitus (T1DM). The purpose of this review is to give a clinically relevant overview of the newer basal and bolus insulin analogues and to highlight their practicalities of use and advantages in specific categories of patients with T1DM.

RECENT FINDINGS

Second-generation rapid-acting insulin analogues (i.e. faster insulin aspart and ultrarapid-acting lispro) have shown to be safe, efficient and superior in controlling postprandial plasma glucose levels without an increase in hypoglycaemia. The newest basal insulin analogues, insulin glargine U300 and degludec, have proven to be efficient in reducing hypoglycaemic events due to a more stable action profile.

SUMMARY

The second-generation rapid-acting and basal insulin analogues approach better the desired physiological insulin pattern of the beta cell. Due to a faster absorption, it is possible to inject the prandial insulin analogues more closely or even after meals without compromising postprandial glucose control. Due to more stable release patterns, basal insulins now have more reliable and longer profiles, covering basal insulin demands in a superior way, leading to a better glycaemic control with less hypoglycaemia (especially nocturnal events) and an improved quality of life.

Improving the treatment of patients with diabetes using insulin analogues: current findings and future directions

Introduction: The aim of insulin replacement in insulin-deficient people (type 1 diabetes, pancreatic causes of diabetes, long-standing type 2 diabetes) is to approximate the physiologic insulin action profile as closely as possible. However, short-acting human insulins start too slow and act too long, causing postprandial hyperglycemia and delayed hypoglycemia, while the insulin action profile of long-acting human insulins is too variable in duration and strength of action, leading to insufficient basal insulin covering and peak insulin levels after injection causing early nocturnal hypoglycemia. Insulin analogues were designed to overcome these shortcomings. In insulin-resistant people (type 2 diabetes), insulin analogues contribute to more efficient and safer insulin supplementation. Areas covered: In this review, we describe the unmet needs for insulin therapy, the currently available short- and long-acting insulin analogues and some considerations on cardiovascular outcomes, use in special populations, and cost-effectiveness. Finally, we discuss what is new in the field of insulin analogues. Expert opinion: The development of insulin analogues is an important step in diabetes treatment. Despite many patients meeting their glycemic targets with the newest analogues, hypoglycemic episodes remain a major problem. More physiologic insulin regimens, with glucose-sensitive or organ-targeting insulin analogues may be the answer to these issues.

Glucose variability and diabetes complications: Risk factor or biomarker? Can we disentangle the "Gordian Knot"?

« Variability in glucose homoeostasis » is a better description than « glycaemic variability » as it encompasses two categories of dysglycaemic disorders: i) the short-term daily glucose fluctuations and ii) long-term weekly, monthly or quarterly changes in either HbA1c, fasting or postprandial plasma glucose. Presently, the relationship between the "variability in glucose homoeostasis" and diabetes complications has never been fully clarified because studies are either observational or limited to retrospective analysis of trials not primarily designed to address this issue. Despite the absence of definitive evidence from randomized controlled trials (RCTs), it is most likely that acute and long-term glucose homoeostasis "cycling", akin to weight and blood pressure "cycling" in obese and hypertensive individuals, are additional risk factors for diabetes complications in the presence of sustained ambient hyperglycaemia. As hypoglycaemic events are strongly associated with short- and long-term glucose variability, two relevant messages can be formulated. Firstly, due consideration should be given to avoid within-day glucose fluctuations in excess of 36% (coefficient of variation) at least for minimizing the inconvenience and dangers associated with hypoglycaemia. Secondly, it seems appropriate to consider that variability in glucose homoeostasis is not only associated with cardiovascular events but is also a causative risk factor via hypoglycaemic episodes as intermediary step. Untangling the" Gordian Knot", to provide confirmation about the impact of variability in glucose homoeostasis and diabetes complications remains a daunting prospect.

Fast-Acting Insulin Aspart Use with the MiniMedTM 670G System

Background: This study assessed the efficacy and safety of ultrarapid insulin Fiasp^® in the hybrid closed-loop MiniMed™ 670G system. Methods: This was a pilot randomized double-blinded crossover study among established MiniMed™ 670G users comparing percentage time in range (TIR) and hypoglycemia for Novolog^® and Fiasp. After 2 weeks optimization with their home insulin, participants were randomized to receive Novolog or Fiasp for 2 weeks, followed by the other insulin for the next 2 weeks. Data from the second week of blinded insulin use were analyzed to allow 1 week for 670G adaptation. During the second week, individuals were asked to eat the same breakfast for 3 days to assess differences in meal pharmacodynamics. Results: Nineteen adults were recruited with mean age of 40 ± 18 years, diabetes duration of 27 ± 12 years, and median hemoglobin A1c of 7.1% (6.9, 7.5), using 0.72 (0.4, 1.2) units/(kg·day). For Novolog and Fiasp, respectively, the %TIR (70-180 mg/dL) was 75.3 ± 9.5 and 78.4 ± 9.3; %time <70 mg/dL was 3.1 ± 2.1 and 2.3 ± 2.0; %time >180 mg/dL was 21.6 ± 9.0 and 19.3 ± 8.9; mean glucose was 147 ± 12 and 146 ± 12 mg/dL; coefficient of variation was 28.6% ± 4.5% and 26.8% ± 4.4%; %time in auto mode 86.4 ± 9.2 and 84.4 ± 9.2. All comparisons were nonsignificant for insulin type. Total daily dose (Novolog 48.8 ± 28.4 vs. Fiasp 52.4 ± 31.7 units; P = 0.01) and daily basal (Novolog 17.6 [15.5, 33.8] vs. Fiasp 19.1 [15.3, 38.5] units; P = 0.07) correlated with TIR and %time >180 mg/dL. For insulin delivery in auto mode there was no statistical difference in total daily dose or daily basal between arms. Paired analysis for matched breakfast meals revealed no significant differences in time to maximum glucose, peak glucose, or glucose excursion. Conclusions: In this pilot study, the use of either Novolog or Fiasp in a commercially available MiniMed 670G system operating in auto mode resulted in clinically similar glycemic outcomes, with a slight increase in daily insulin requirements using Fiasp.

Ultrafast acting insulin analog - a new way to prevent postprandial hyperglycemia and improve quality of life in type 1 diabetes patients - case reports

The aim of modern insulin therapy used in the treatment of type 1 diabetes mellitus is to mimic the physiological secretion of insulin in order to ensure stable normoglycemia while maintaining the greatest possible comfort of life for diabetic patients. New ultra-fast insulin analogs that can be administered immediately before a meal contribute to the improvement of postprandial glycemia and the quality of life of patients. We presented two cases illustrating the effectiveness and safety of the use of an ultra-fast-acting insulin analog in the treatment of postprandial hyperglycemia in children with type 1 diabetes.

Randomized Double-Blind Clinical Trial Comparing Ultra Rapid Lispro With Lispro in a Basal-Bolus Regimen in Patients With Type 2 Diabetes: PRONTO-T2D

OBJECTIVE

To evaluate the efficacy and safety of ultra rapid lispro (URLi) versus lispro in patients with type 2 diabetes on a basal-bolus insulin regimen.

RESEARCH DESIGN AND METHODS

This was a phase 3, treat-to-target, double-blind 26-week study. After an 8-week lead-in to optimize basal insulin glargine or degludec in combination with prandial lispro treatment, patients were randomized to blinded URLi (n = 336) or lispro (n = 337) injected 0-2 min prior to meals. Patients could continue metformin and/or a sodium-glucose cotransporter 2 inhibitor. The primary end point was change in HbA1c from baseline to 26 weeks (noninferiority margin 0.4%), with multiplicity-adjusted objectives for postprandial glucose (PPG) excursions during a standardized meal test.

RESULTS

HbA1c improved for both URLi and lispro, and noninferiority was confirmed: estimated treatment difference (ETD) 0.06% (95% CI -0.05; 0.16). Mean change in HbA1c was -0.38% for URLi and -0.43% for lispro, with an end-of-treatment HbA1c of 6.92% and 6.86%, respectively. URLi was superior to lispro in controlling 1- and 2-h PPG excursions: 1-h ETD, -0.66 mmol/L (95% CI -1.01, -0.30); 2-h ETD, -0.96 mmol/L (-1.41, -0.52). Significantly lower PPG excursions were evident from 0.5 to 4.0 h postmeal with URLi treatment. There were no significant treatment differences in rates of severe or documented hypoglycemia (<3.0 mmol/L). Incidence of overall treatment-emergent adverse events was similar between treatments.

CONCLUSIONS

URLi compared with lispro in a basal-bolus regimen was confirmed to be noninferior for HbA1c and superior to lispro for PPG control in patients with type 2 diabetes.

Production of a novel heterodimeric two-chain insulin-Fc fusion protein

Insulin is a peptide hormone produced by the pancreas. The physiological role of insulin is the regulation of glucose metabolism. Under certain pathological conditions the insulin levels can be reduced leading to the metabolic disorder diabetes mellitus (DM). For type 1 DM and, dependent on the disease progression for type 2 DM, insulin substitution becomes indispensable. To relieve insulin substitution therapy for patients, novel insulin analogs with pharmacokinetic and pharmacodynamic profiles aiming for long-lasting or fast-acting insulins have been developed. The next step in the evolution of novel insulins should be insulin analogs with a time action profile beyond 1-2 days, preferable up to 1 week. Nowadays, insulin is produced in a recombinant manner. This approach facilitates the design and production of further insulin-analogs or insulin-fusion proteins. The usage of the Fc-domain from immunoglobulin as a fusion partner for therapeutic proteins and peptides is widely used to extend their plasma half-life. Insulin consists of two chains, the A- and B-chain, which are connected by two disulfide-bridges. To produce a novel kind of Fc-fusion protein we have fused the A-chain as well as the B-chain to Fc-fragments containing either 'knob' or 'hole' mutations. The 'knob-into-hole' technique is frequently used to force heterodimerization of the Fc-domain. Using this approach, we were able to produce different variants of two-chain-insulin-Fc-protein (tcI-Fc-protein) variants. The tcI-Fc-fusion variants retained activity as shown in in vitro assays. Finally, prolonged blood glucose lowering activity was demonstrated in normoglycemic rats. Overall, we describe here the production of novel insulin-Fc-fusion proteins with prolonged times of action.

Amphiphilic Polyacrylamide Excipients Lead to a Record-Breaking Fast-Acting Insulin

Fast-acting insulins are central to the regulation of prandial glucose in diabetic patients. Current fast-acting insulins require 20-30 min for the onset and longer for the peak blood concentrations. The recent work by Mann et al. used high-throughput synthesis and screening of polyacrylamide-based excipients to yield a formulation with pharmacokinetics that is faster than the currently available fast-acting insulins.

The continuing quest for better subcutaneously administered prandial insulins: a review of recent developments and potential clinical implications

The class of rapid-acting insulin analogues were introduced more than 20 years ago to control postprandial plasma glucose (PPG) excursions better than unmodified regular human insulin. Insulins, lispro, aspart and glulisine all achieved an earlier onset of action, greater peak effect and shorter duration of action resulting in lower PPG levels and a reduced risk of late postprandial hypoglycaemia. However, the subcutaneous absorption rate of these analogues still fails to match the physiological profile of insulin in the systemic circulation following a meal. Recent reformulations of aspart and lispro have generated a second generation of more rapid-acting insulin analogue candidates, including fast-acting aspart (faster aspart), ultra-rapid lispro and BioChaperone Lispro. These modifications have the potential to mimic physiological prandial insulin secretion better with an even earlier onset of action with improved PPG control, shorter duration of effect and reduced risk of hypoglycaemia. Recent phase 3 trials in type 1 and type 2 diabetes show that faster aspart and ultra-rapid lispro compared with conventional aspart and lispro, achieved fewer PPG excursions with a small increase in post-meal hypoglycaemia but similar or marginally superior glycated haemoglobin levels, and suggest the need for parallel optimization of basal insulin replacement. Phase 1 trials for BioChaperone Lispro are equally encouraging with phase 3 trials yet to be initiated. Comparative analysis of the clinical and pharmacological evidence for these new prandial insulin candidates in the treatment of type 1 and type 2 diabetes is the main focus of this review.