Minimizing morbidity of hypoglycemia in diabetes: a review of mini-dose glucagon

Comparison of Intranasal and Injectable Glucagon Administration Among Pediatric Population Responders

Aims: Ease of use and acceptability of nasal versus injectable glucagon (IG) among pediatric responders have been little investigated. This study compared the performance of administering nasal and IG in parents of youth with type 1 diabetes (T1D) and in school workers. Enablers and barriers associated with each glucagon and preferred glucagon administration learning modality were also evaluated. Methods: Three months after watching short pedagogical videos, 30 parents and 30 school workers performed simulated scenarios where they administered both glucagon. Completion time and successful execution of critical steps were collected. Interviews assessed preferred learning modalities, barriers, and enablers associated with each glucagon. Results: Both groups administered nasal glucagon faster than IG (median [interquartile range]: parents 19 [12-29] vs. 97 [71-117] s, P < 0.001; school workers 24 [16-33] vs. 129 [105-165] s, P < 0.001). A lower proportion of participants successfully executed all critical steps for injectable versus nasal glucagon (significant difference for school workers [53% vs. 90%; P = 0.007] but not for parents [68% vs. 83%; P = 0.227]). Nasal glucagon was preferred for ease of use and acceptability. Preferred learning modalities were a combination of videos and workshops, but videos alone could suffice for nasal glucagon. Conclusions: Nasal glucagon is faster to use, more likely to be successfully administered, and more acceptable than IG for parents of children with T1D and school workers. Nasal glucagon training with videos could improve school workers' involvement in severe hypoglycemia management. Clinical Trial number, URL to the registration: NCT05395000, https://clinicaltrials.gov/ct2/show/NCT05395000.

Emerging Diabetes Technologies: Continuous Glucose Monitors/Artificial Pancreases

Over the past decade there have been many advances in diabetes technologies, such as continuous glucose monitors (CGM s), insulin-delivery devices, and hybrid closed loop systems . Now most CGMs (Medtronic-Guardian, Dexcom-G6, and Abbott-Libre-2) have MARD values of < 10%, in contrast to two decades ago when the MARD used to be > 20%. In addition, the majority of the new CGMs do not require calibrations, and the latest CGMs last for 10-14 days. An implantable 6-months CGM by Eversense-3 is now approved in the USA and Europe. Recently, the FDA approved Libre 3 which provides real-time glucose values every minute. Even though it is approved as an iCGM it is not interoperable with automatic-insulin-delivery (AID) systems. The newer CGMs that are likely to be launched in the next few months in the USA include the 10-11 days Dexcom G7 (60% smaller than the existing G6), and the 7-days Medtronic Guardian 4. Most of the newer CGM have several features like automatic initialization, easy insertion, predictive alarms, and alerts. It has also been noticed that an arm insertion site might have better accuracy than abdomen or other sites, like the buttock for kids. Lag time between YSI and different sensors have been reported differently, sometimes it is down to 2-3 min; however, in many instances, it is still 15-20 min, especially when the rate of change of glucose is > 2 mg/min. We believe that in the next decade there will be a significant increase in the number of people who use CGM for their day-to-day diabetes care.

New Developments in Glucagon Treatment for Hypoglycemia

Glucagon is essential for endogenous glucose regulation along with the paired hormone, insulin. Unlike insulin, pharmaceutical use of glucagon has been limited due to the unstable nature of the peptide. Glucagon has the potential to address hypoglycemia as a major limiting factor in the treatment of diabetes, which remains very common in the type 1 and type 2 diabetes. Recent developments are poised to change this paradigm and expand the use of glucagon for people with diabetes. Glucagon emergency kits have major limitations for their use in treating severe hypoglycemia. A complicated reconstitution and injection process often results in incomplete or aborted administration. New preparations include intranasal glucagon with an easy-to-use and needle-free nasal applicator as well as two stable liquid formulations in pre-filled injection devices. These may ease the burden of severe hypoglycemia treatment. The liquid preparations may also have a role in the treatment of non-severe hypoglycemia. Despite potential benefits of expanded use of glucagon, undesirable side effects (nausea, vomiting), cost, and complexity of adding another medication may limit real-world use. Additionally, more long-term safety and outcome data are needed before widespread, frequent use of glucagon is recommended by providers.

Pharmacokinetics of Intraperitoneally Delivered Glucagon in Pigs: A Hypothesis of First Pass Metabolism

Background and Objective

Artificial pancreases administering low-dose glucagon in addition to insulin have the scope to improve glucose control in patients with diabetes mellitus type 1. If such a device were to deliver both hormones intraperitoneally, it would mimic normal physiology, which may be beneficial. However, the pharmacokinetic properties of glucagon after intraperitoneal administration are not well known. Hence, the current study aims to evaluate the relationship between the amount of intraperitoneally delivered glucagon and pharmacokinetic variables in a pig model.

Methods

Pharmacokinetic data was retrieved from experiments on 19 anaesthetised pigs and analysed post hoc. The animals received a single intraperitoneal bolus of glucagon ranging from 0.30 to 4.46 µg/kg. Plasma glucagon was measured every 2–10 min for 50 min.

Results

Peak plasma concentration and area under the time–plasma concentration curve of glucagon correlated positively with the administered dose, and larger boluses provided a relatively greater increase. The mean (standard deviation) time to maximum glucagon concentration in plasma was 11 (5) min, and the mean elimination half-life of glucagon in plasma was 19 (7) min.

Conclusions

Maximum plasma concentration and area under the time–plasma concentration curve of glucagon increase nonlinearly in relation to the intraperitoneally administered glucagon dose. We hypothesise that the results are compatible with a satiable first-pass metabolism in the liver. Time to maximum glucagon concentration in plasma and the elimination half-life of glucagon in plasma seem independent of the drug dose.

Glucagon for hypoglycaemia treatment in type 1 diabetes

To achieve strict glycaemic control and avoid chronic diabetes complications, individuals with type 1 diabetes (T1D) are recommended to follow an intensive insulin regimen. However, the risk and fear of hypoglycaemia often prevent individuals from achieving the treatment goals. Apart from early insulin suspension in insulin pump users, carbohydrate ingestion is the only option for preventing and treating non-severe hypoglycaemic events. These rescue treatments may give extra calories and cause overweight. As an alternative, the use of low-dose glucagon to counter hypoglycaemia has been proposed as a tool to raise glucose concentrations without adding extra calories. Previously, the commercially available glucagon formulations required reconstitution from powder to a solution before being injected subcutaneously or intramuscularly-making it practical only for treating severe hypoglycaemia. Several companies have developed more stable formulations that do not require the time-consuming reconstitution process before use. As well as treating severe hypoglycaemia, non-severe and impending hypoglycaemia can also be treated with lower doses of glucagon. Once available, low-dose glucagon can be either delivered manually, as an injection, or automatically, by an infusion pump. This review focuses on the role and perspectives of using glucagon to treat and prevent hypoglycaemia in T1D.

Glucagon-based therapy: Past, present and future

Diabesity and its related cardio-hepato-renal complications are of absolute concern globally. Last decade has witnessed a growing interest in the scientific community in investigating novel pharmaco-therapies employing the pancreatic hormone, glucagon. Canonically, this polypeptide hormone is known for its use in rescue treatment for hypoglycaemic shocks owing to its involvement in the counter-regulatory feedback mechanism. However, substantial studies in the recent past elucidated the pleiotropic effects of glucagon in diabesity and related complications like non-alcoholic steatohepatitis (NASH) and non-alcoholic fatty liver disease (NAFLD). Thus, the dual nature of this peptide has sparked the search for drugs that can modify glucagon signalling to combat hypoglycaemia or diabesity. Thus far, researchers have explored various pharmacological approaches to utilise this peptide in imminent modern therapies. The research endeavours in this segment led to explorations of stable glucagon formulations/analogues, glucagon receptor antagonism, glucagon receptor agonism, and incretin poly-agonism as new strategies for the management of hypoglycaemia or diabesity. This 'three-dimensional' research on glucagon resulted in the discovery of various drug candidates that proficiently modify glucagon signalling. Currently, several emerging glucagon-based therapies are under pre-clinical and clinical development. We sought to summarise the recent progress to comprehend glucagon-mediated pleiotropic effects, provide an overview of drug candidates currently being developed and future perspectives in this research domain.

Mini-doses of glucagon to prevent hypoglycemia in children with type 1 diabetes refusing food: a case series

AIMS

Hypoglycemia in small children with type 1 diabetes is difficult to manage if nausea, vomit or food refusal occurs. If oral carbohydrate cannot be used, there is a hypothetical risk of severe hypoglycemia. The present article describes the effect on glucose of small doses of subcutaneous glucagon to revert hypoglycemia and prevent severe events in small children with type 1 diabetes using a continuous glucose monitoring.

METHODS

We analyzed 4 episodes of impending or mild hypoglycemia in 3 children with type 1 diabetes who refused to eat carbohydrates. Using a standard U-100 insulin syringe, children received one "unit" (10 μg) of glucagon subcutaneously for every year of age up to 15 units (150 μg). If the blood glucose did not increase within 30 min, the initial dosage was repeated at that time. Instructions were given by phone from the physician. At the following visit data from continuous glucose monitoring devices, insulin pump and glucometer were downloaded and reviewed retrospectively from the physician.

RESULTS

Blood glucose from continuous glucose monitoring after one and 2 h was 127 ± 80 mg/dl and 165 ± 78 mg/dl, respectively. After a glucagon injection, there was a single recurrence of hypoglycemia, requiring another shot. The glucagon was well tolerated, except for nausea, present before the injection. None of the children were taken to our hospital because of concerns for hypoglycemia.

CONCLUSION

Mini-doses of glucagon given subcutaneously were effective and safe in preventing frank or impending hypoglycemia in type 1 diabetes children refusing food.

Severe Hypoglycemia: Is It Still a Threat for Children and Adolescents With Type 1 Diabetes?

Severe hypoglycemia is defined as a condition with serious cognitive dysfunction, such as a convulsion and coma, requiring external help from other persons. This condition is still lethal and is reported to be the cause of death in 4-10% in children and adolescents with type 1 diabetes. The incidence of severe hypoglycemia in the pediatric population was previously reported as high as more than 50-100 patient-years; however, there was a decline in the frequency of severe hypoglycemia during the past decades, and relationship with glycemic control became weaker than previously reported. A lot of studies have shown the neurological sequelae with severe hypoglycemia as cognitive dysfunction and abnormalities in brain structure. This serious condition also provides negative psychosocial outcomes and undesirable compensatory behaviors. Various possible factors, such as younger age, recurrent hypoglycemia, nocturnal hypoglycemia, and impaired awareness of hypoglycemia, are possible risk factors for developing severe hypoglycemia. A low HbA_1c level is not a predictable value for severe hypoglycemia. Prevention of severe hypoglycemia remains one of the most critical issues in the management of pediatric patients with type 1 diabetes. Advanced technologies, such as continuous glucose monitoring (CGM), intermittently scanned CGM, and sensor-augmented pump therapy with low-glucose suspend system, potentially minimize the occurrence of severe hypoglycemia without worsening overall glycemic control. Hybrid closed-loop system must be the most promising tool for achieving optimal glycemic control with preventing the occurrence of severe hypoglycemia in pediatric patients with type 1 diabetes.

Human Factors Usability and Validation Studies of a Glucagon Autoinjector in a Simulated Severe Hypoglycemia Rescue Situation

Background: A room-temperature stable, soluble liquid glucagon formulation loaded into a prefilled, single-use, two-step autoinjector is under development for severe hypoglycemia rescue. We report a human factors validation program evaluating the glucagon autoinjector (GAI) (Gvoke HypoPen™; Xeris Pharmaceuticals, Inc., Chicago, IL) versus marketed glucagon emergency kits (GEKs) for managing severe hypoglycemia. Methods: A simulated-use human factors usability study was conducted with the GAI versus marketed GEKs in 16 participants, including adult caregivers and first responders, experienced with glucagon administration. A summative human factors validation study of the GAI was conducted with 75 volunteers. Participants were (1) trained on the device and procedure or (2) given time to individually read the instructions and familiarize themselves with the device. Participants returned a week later to perform an unaided rescue attempt that simulated rescue of patients with diabetes suffering a hypoglycemia emergency. Participant actions were recorded for critical rescue tasks and use errors. Results: In the usability study, 88% (14) successfully administered a rescue injection using the GAI versus 31% (5) using GEKs (P < 0.05). Mean total rescue time of use was 47.9 s with the GAI versus 109.0 s with GEKs (P < 0.05). In the validation study, 98.7% successfully administered the rescue injection using the GAI. Overall, there were no patterns of differences between trained versus untrained participants, between caregivers versus first responders or between adults versus adolescents. Conclusion: The GAI and instructional materials can be correctly, safely, and effectively used by intended user, which support continued development of the GAI as an alternative to GEKs.

New uses and formulations of glucagon for hypoglycaemia

Hypoglycaemia is the more frequent complication of insulin therapy and the main barrier to tight glycaemic control. Injectable glucagon and oral intake of carbohydrates are the recommended treatments for severe and non-severe hypoglycaemia episodes, respectively. Nasal glucagon is currently being developed as a ready-to-use device, to simplify severe hypoglycaemia rescue. Stable forms of liquid glucagon could open the field for different approaches for mild to moderate hypoglycaemia treatment, such as mini-doses of glucagon or continuous subcutaneous glucagon infusion as a part of dual-hormone closed-loop systems. Pharmaceutical companies are developing stable forms of native glucagon or glucagon analogues for that purpose.

Stable Liquid Glucagon: Beyond Emergency Hypoglycemia Rescue

Glycemic control is the mainstay of preventing diabetes complications at the expense of increased risk of hypoglycemia. Severe hypoglycemia negatively impacts the quality of life of patients with type 1 diabetes and can lead to morbidity and mortality. Currently available glucagon emergency kits are effective at treating hypoglycemia when correctly used, however use is complicated especially by untrained persons. Better formulations and devices for glucagon treatment of hypoglycemia are needed, specifically stable liquid glucagon. Out of the scope of this review, other potential uses of stable liquid glucagon include congenital hyperinsulinism, post-bariatric surgery hypoglycemia, and insulinoma induced hypoglycemia. In the 35 years since Food and Drug Administration (FDA) approval of the first liquid stable human recombinant insulin, we continue to wait for the glucagon counterpart. For mild hypoglycemia, a commercially available liquid stable glucagon would enable more widespread implementation of mini-dose glucagon use as well as glucagon in dual hormone closed-loop systems. This review focuses on the current and upcoming pharmaceutical uses of glucagon in the treatment of type 1 diabetes with an outlook on stable liquid glucagon preparations that will hopefully be available for use in patients in the near future.

Cross-Validation of a Glucose-Insulin-Glucagon Pharmacodynamics Model for Simulation Using Data From Patients With Type 1 Diabetes

BACKGROUND

Currently, no consensus exists on a model describing endogenous glucose production (EGP) as a function of glucagon concentrations. Reliable simulations to determine the glucagon dose preventing or treating hypoglycemia or to tune a dual-hormone artificial pancreas control algorithm need a validated glucoregulatory model including the effect of glucagon.

METHODS

Eight type 1 diabetes (T1D) patients each received a subcutaneous (SC) bolus of insulin on four study days to induce mild hypoglycemia followed by a SC bolus of saline or 100, 200, or 300 µg of glucagon. Blood samples were analyzed for concentrations of glucagon, insulin, and glucose. We fitted pharmacokinetic (PK) models to insulin and glucagon data using maximum likelihood and maximum a posteriori estimation methods. Similarly, we fitted a pharmacodynamic (PD) model to glucose data. The PD model included multiplicative effects of insulin and glucagon on EGP. Bias and precision of PD model test fits were assessed by mean predictive error (MPE) and mean absolute predictive error (MAPE).

RESULTS

Assuming constant variables in a subject across nonoutlier visits and using thresholds of ±15% MPE and 20% MAPE, we accepted at least one and at most three PD model test fits in each of the seven subjects. Thus, we successfully validated the PD model by leave-one-out cross-validation in seven out of eight T1D patients.

CONCLUSIONS

The PD model accurately simulates glucose excursions based on plasma insulin and glucagon concentrations. The reported PK/PD model including equations and fitted parameters allows for in silico experiments that may help improve diabetes treatment involving glucagon for prevention of hypoglycemia.

Comparative Pharmacokinetic/Pharmacodynamic Study of Liquid Stable Glucagon Versus Lyophilized Glucagon in Type 1 Diabetes Subjects

BACKGROUND

There is currently no stable liquid form of glucagon commercially available. The aim of this study is to assess the speed of absorption and onset of action of G-Pump™ glucagon at 3 doses as compared to GlucaGen®, all delivered subcutaneously via an OmniPod®.

METHODS

Nineteen adult subjects with type 1 diabetes participated in this Phase 2, randomized, double-blind, cross-over, pharmacokinetic/pharmacodynamic study. Subjects were given 0.3, 1.2, and 2.0 µg/kg each of G-Pump glucagon and GlucaGen via an OmniPod.

RESULTS

G-Pump glucagon effectively increased blood glucose levels in a dose-dependent fashion with a glucose Cmax of 183, 200, and 210 mg/dL at doses of 0.3, 1.2, and 2.0 µg/kg, respectively (P = ns vs GlucaGen). Mean increases in blood glucose from baseline were 29.2, 52.9, and 77.7 mg/dL for G-Pump doses of 0.3, 1.2, and 2.0 µg/kg, respectively. There were no statistically significant differences between treatments in the glucose T50%-early or glucagon T50%-early with one exception. The glucagon T50%-early was greater following G-Pump treatment at the 2.0 μg/kg dose (13.9 ± 4.7 min) compared with GlucaGen treatment at the 2.0 μg/kg dose (11.0 ± 3.1 min, P = .018). There was more pain and erythema at the infusion site with G-Pump as compared to GlucaGen. No serious adverse events were reported, and no unexpected safety issues were observed.

CONCLUSIONS

G-Pump glucagon is a novel, stable glucagon formulation with similar PK/PD properties as GlucaGen, but was associated with more pain and infusion site reactions as the dose increased, as compared to GlucaGen.

Pyridyl-alanine as a Hydrophilic, Aromatic Element in Peptide Structural Optimization

Glucagon (Gcg) 1 serves a seminal physiological role in buffering against hypoglycemia, but its poor biophysical properties severely complicate its medicinal use. We report a series of novel glucagon analogues of enhanced aqueous solubility and stability at neutral pH, anchored by Gcg[Aib16]. Incorporation of 3- and 4-pyridyl-alanine (3-Pal and 4-Pal) enhanced aqueous solubility of glucagon while maintaining biological properties. Relative to native hormone, analogue 9 (Gcg[3-Pal6,10,13, Aib16]) demonstrated superior biophysical character, better suitability for medicinal purposes, and comparable pharmacology against insulin-induced hypoglycemia in rats and pigs. Our data indicate that Pal is a versatile surrogate to natural aromatic amino acids and can be employed as an alternative or supplement with isoelectric adjustment to refine the biophysical character of peptide drug candidates.

Nonaqueous, Mini-Dose Glucagon for Treatment of Mild Hypoglycemia in Adults With Type 1 Diabetes: A Dose-Seeking Study

OBJECTIVE

To evaluate mini-dose glucagon in adults with type 1 diabetes using a stable, liquid, ready-to-use preparation.

RESEARCH DESIGN AND METHODS

Twelve adults with type 1 diabetes receiving treatment with insulin pumps received subcutaneous doses of 75, 150, and 300 μg of nonaqueous glucagon. Plasma glucose, glucagon, and insulin concentrations were measured. At 180 min, subjects received insulin followed in ~60 min by a second identical dose of glucagon.

RESULTS

Mean (±SE) fasting glucose concentrations (mg/dL) were 110 ± 7, 110 ± 10, and 109 ± 9 for the 75-, 150-, and 300-μg doses, respectively, increasing maximally at 60 min by 33, 64, and 95 mg/dL (all P < 0.001). The post-insulin administration glucose concentrations were 70 ± 2, 74 ± 5, and 70 ± 2 mg/dL, respectively, with maximal increases of 19, 24, and 43 mg/dL post-glucagon administration (P < 0.02) at 45-60 min.

CONCLUSIONS

Subcutaneous, nonaqueous, ready-to-use G-Pen Mini glucagon may provide an alternative to oral carbohydrates for the management of anticipated, impending, or mild hypoglycemia in adults with type 1 diabetes.