A Randomized, Placebo-Controlled Double-Blind Trial of a Closed-Loop Glucagon System for Postbariatric Hypoglycemia.

BACKGROUND: Postbariatric hypoglycemia (PBH) can threaten safety and reduce quality of life. Current therapies are incompletely effective. METHODS: Patients with PBH were enrolled in a double-blind, placebo-controlled, crossover trial to evaluate a closed-loop glucose-responsive automated glucagon delivery system designed to reduce severe hypoglycemia. A hypoglycemia detection and mitigation algorithm was embedded in the artificial pancreas system connected to a continuous glucose monitor (CGM, Dexcom) driving a patch infusion pump (Insulet) filled with liquid investigational glucagon (Xeris) or placebo (vehicle). Sensor/plasma glucose responses to mixed meal were assessed during 2 study visits. The system delivered up to 2 doses of study drug (300/150 µg glucagon or equal-volume vehicle) if triggered by the algorithm. Rescue dextrose was given for plasma glucose <55 mg/dL or neuroglycopenia. RESULTS: Twelve participants (11 females/1 male, age 52 ± 2, 8 ± 1 years postsurgery, mean ± SEM) completed all visits. Predictive hypoglycemia alerts prompted automated drug delivery postmeal, when sensor glucose was 114 ± 7 vs 121 ± 5 mg/dL (P = .39). Seven participants required rescue glucose after vehicle but not glucagon (P = .008). Five participants had severe hypoglycemia (<55 mg/dL) after vehicle but not glucagon (P = .03). Nadir plasma glucose was higher with glucagon vs vehicle (67 ± 3 vs 59 ± 2 mg/dL, P = .004). Plasma glucagon rose after glucagon delivery (1231 ± 187 vs 16 ± 1 pg/mL at 30 minutes, P = .001). No rebound hyperglycemia occurred. Transient infusion site discomfort was reported with both glucagon (n = 11/12) and vehicle (n = 10/12). No other adverse events were observed. CONCLUSION: A CGM-guided closed-loop rescue system can detect imminent hypoglycemia and deliver glucagon, reducing severe hypoglycemia in PBH. CLINICAL TRIALS REGISTRATION: NCT03255629.

Human factors studies of a prefilled syringe with stable liquid glucagon in a simulated severe hypoglycemia rescue situation.

Background: Two human factors studies evaluated whether a stable liquid formulation of glucagon in a prefilled syringe (G-PFS) could be safely and effectively administered and evaluated the effectiveness of the product label guide and instructions-for-use (IFU). Research design and methods: In a formative study, 11 participants received orientation with the G-PFS instructional materials and performed a single unaided rescue attempt. In the validation study, 75 adult and adolescent participants received training or familiarized themselves with the G-PFS IFU, Label Guide, and device. All participants returned 1 week later to perform a single unaided rescue attempt of a simulated person with diabetes suffering from an emergency severe hypoglycemic event. Results: The formative study resulted in a 100% success rate across all rescue dose attempts. The validation study resulted in 74/75 (99%) of participants successfully using the G-PFS to administer the full glucagon rescue dose, and validated that intended users could learn from, comprehend, and recall the G-PFS instructions to successfully use the product. Conclusion: The G-PFS provides a familiar, easy-to-use alternative to currently marketed lyophilized glucagon kits for treating severe hypoglycemia. The G-PFS IFU and Label Guide enable even untrained users to successfully administer a full rescue dose of stable liquid glucagon.

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.

Mini-Dose Glucagon as a Novel Approach to Prevent Exercise-Induced Hypoglycemia in Type 1 Diabetes.

OBJECTIVE: Patients with type 1 diabetes who do aerobic exercise often experience a drop in blood glucose concentration that can result in hypoglycemia. Current approaches to prevent exercise-induced hypoglycemia include reduction in insulin dose or ingestion of carbohydrates, but these strategies may still result in hypoglycemia or hyperglycemia. We sought to determine whether mini-dose glucagon (MDG) given subcutaneously before exercise could prevent subsequent glucose lowering and to compare the glycemic response to current approaches for mitigating exercise-associated hypoglycemia. RESEARCH DESIGN AND METHODS: We conducted a four-session, randomized crossover trial involving 15 adults with type 1 diabetes treated with continuous subcutaneous insulin infusion who exercised fasting in the morning at ∼55% VO2max for 45 min under conditions of no intervention (control), 50% basal insulin reduction, 40-g oral glucose tablets, or 150-µg subcutaneous glucagon (MDG). RESULTS: During exercise and early recovery from exercise, plasma glucose increased slightly with MDG compared with a decrease with control and insulin reduction and a greater increase with glucose tablets (P < 0.001). Insulin levels were not different among sessions, whereas glucagon increased with MDG administration (P < 0.001). Hypoglycemia (plasma glucose <70 mg/dL) was experienced by six subjects during control, five subjects during insulin reduction, and none with glucose tablets or MDG; five subjects experienced hyperglycemia (plasma glucose ≥250 mg/dL) with glucose tablets and one with MDG. CONCLUSIONS: MDG may be more effective than insulin reduction for preventing exercise-induced hypoglycemia and may result in less postintervention hyperglycemia than ingestion of carbohydrate.

Design and Clinical Evaluation of a Novel Low-Glucose Prediction Algorithm with Mini-Dose Stable Glucagon Delivery in Post-Bariatric Hypoglycemia.

BACKGROUND: Postbariatric hypoglycemia (PBH) is a complication of bariatric surgery with limited therapeutic options. We developed an event-based system to predict and detect hypoglycemia based on continuous glucose monitor (CGM) data and recommend delivery of minidose liquid glucagon. METHODS: We performed an iterative development clinical study employing a novel glucagon delivery system: a Dexcom CGM connected to a Windows tablet running a hypoglycemia prediction algorithm and an Omnipod pump filled with an investigational stable liquid glucagon formulation. Meal tolerance testing was performed in seven participants with PBH and history of neuroglycopenia. Glucagon was administered when hypoglycemia was predicted. Primary outcome measures included the safety and feasibility of this system to predict and prevent severe hypoglycemia. Secondary outcomes included hypoglycemia prediction by the prediction algorithm, minimization of time below hypoglycemia threshold using glucagon, and prevention of rebound hyperglycemia. RESULTS: The hypoglycemia prediction algorithm alerted for impending hypoglycemia in the postmeal state, prompting delivery of glucagon (150 µg). After observations of initial incomplete efficacy to prevent hypoglycemia in the first two participants, system modifications were implemented: addition of PBH-specific detection algorithm, increased glucagon dose (300 µg), and a second glucagon dose if needed. These modifications, together with rescue carbohydrates provided to some participants, contributed to progressive improvements in glucose time above the hypoglycemia threshold (75 mg/dL). CONCLUSIONS: Preliminary results indicate that our event-based automatic monitoring algorithm successfully predicted likely hypoglycemia. Minidose glucagon therapy was well tolerated, without prolonged or severe hypoglycemia, and without rebound hyperglycemia.

Efficacy and Safety of Mini-Dose Glucagon for Treatment of Nonsevere Hypoglycemia in Adults With Type 1 Diabetes.

Context: Standard treatment of hypoglycemia is oral carbohydrate, but it often results in hyperglycemia and entails extra caloric intake. Objective: To evaluate low-dose glucagon to treat mild hypoglycemia in ambulatory adults with type 1 diabetes (T1D). Design: Randomized crossover trial (two 3-week periods). Setting: Five U.S. diabetes clinics. Patients: Twenty adults with T1D using an insulin pump and continuous glucose monitor (CGM) and experiencing frequent mild hypoglycemia. Intervention: Nonaqueous mini-dose glucagon (MDG) (150 µg) to treat nonsevere hypoglycemia. Main Outcome Measures: Successful treatment was defined as blood glucose (BG) ≥50 mg/dL 15 minutes and ≥70 mg/dL 30 minutes after intervention, on the study meter. Two authors, blinded to treatment arm, independently judged each event as a clinical success or failure. Results: Sixteen participants (mean age 39 years, 75% female, mean diabetes duration 23 years, mean hemoglobin A1c 7.2%) had 118 analyzable events with initial BG of 50 to 69 mg/dL. Successful treatment criteria were met for 58 (94%) of 62 events during the MDG period and 53 (95%) of 56 events during the glucose tablets (TABS) period (adjusted P = 0.99). Clinical assessments of success for these events were 97% and 96%, respectively. CGM-measured time in range did not differ between treatment groups during the 2 hours after events, but TABS resulted in higher maximum glucose (116 vs 102 mg/dL; P = 0.01) over the first hour. Conclusions: Low-dose glucagon can successfully treat mild hypoglycemia and may be a useful alternative to treatment with oral carbohydrate when trying to avoid unnecessary caloric intake.

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.

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.

Development of a highly stable, nonaqueous glucagon formulation for delivery via infusion pump systems.

Despite a vigorous research effort, to date, the development of systems that achieve glucagon stability in aqueous formulations (without reconstitution) has failed to produce any clinical candidates. We have developed a novel, nonaqueous glucagon formulation based on a biocompatible pharmaceutical solvent, dimethyl sulfoxide, which demonstrates excellent physical and chemical stability at relatively high concentrations and at high temperatures. This article reports the development of a novel, biocompatible, nonaqueous native human glucagon formulation for potential use in subcutaneous infusion pump systems. Data are presented that demonstrate physical and chemical stability under presumed storage conditions (>2 years at room temperature) as well as "in use" stability and compatibility in an Insulet's OmniPod(®) infusion pump. Also presented are results of a skin irritation study in a rabbit model and pharmacokinetics/pharmacodynamics data following pump administration of glucagon in a diabetic swine model. This nonaqueous glucagon formulation is suitable for further clinical development in pump systems.