Clinical performance of a device that applies local heat to the insulin infusion site: a crossover study

Predicting monoclonal antibody pharmacokinetics following subcutaneous administration via whole-body physiologically-based modeling

Use of the subcutaneous (SC) route for administering monoclonal antibodies (mAbs) to treat chronic conditions has been hindered because of an incomplete understanding of fundamental mechanisms controlling mAb absorption from the SC site, and due to the limited translatability of preclinical studies. In this paper, we report on the development and evaluation of a whole-body physiologically-based model to predict mAb pharmacokinetics following SC administration. The circulatory model is based on the physiological processes governing mAb transport and includes two mAb-specific parameters representing differences in pinocytosis rate and the diffusive/convective transport rates among mAbs. At the SC administration site, two additional parameters are used to represent mAb differences in lymphatic capillary uptake and in pre-systemic clearance. Model development employed clinical intravenous (IV) plasma PK data from 20 mAbs and SC plasma PK data from 12 of these mAbs, as obtained from the literature. The resulting model reliably described both the IV and SC measured plasma concentration data. In addition, a metric based on the positive charge across the mAb's complementarity determining region vicinity was found to positively correlate with the model-based estimates of the mAb-specific parameter governing organ/tissue pinocytosis transport and with estimates of the mAb's SC lymphatic capillary clearance. These two relationships were incorporated into the model and accurately predicted the SC PK profiles of three out of four separate mAbs not included in model development. The whole-body physiologically-based model reported herein, provides a platform to characterize and predict the plasma disposition of monoclonal antibodies following SC administration in humans.

Environmental effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes mellitus

OBJECTIVE

This study aimed to explore the effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes.

MATERIALS AND METHODS

A three-way, cross-over, randomised study was performed in adults with type 1 diabetes mellitus (n = 10). The pharmacodynamics profile of a single dose of short-acting insulin (insulin lispro) was investigated, using a controlled environmental chamber, under three environmental conditions: (a) temperature: 15°C and humidity: 10%; (b) temperature: 30°C and humidity: 10%; and (c) temperature: 30°C and humidity: 60%. A euglycaemic glucose clamp technique ensured constant blood glucose of 100 mg/dL (5.5 mmol/L). The following pharmacodynamic endpoints were calculated: maximum glucose infusion rate (GIR_max ), time to GIR_max (t_GIRmax ), total area under the curve (AUC) for GIR from 0-6 hours (AUC_GIR.0-6h ), and partial AUCs (AUC_GIR.0-1h , AUC_GIR.0-2h and AUC_GIR.2-6h ).

RESULTS

Higher temperature (30°C) under 10% fixed humidity conditions resulted in greater GIR_max (P = 0.04) and a later t_GIR.max (P = 0.049) compared to lower temperature (15°C). Humidity did not affect any pharmacodynamic parameter. When the combined effects of temperature and humidity were explored, t_GIR.max (P = 0.008) occurred earlier, with a lower late insulin pharmacodynamic effect (AUC_GIR.2-6h ; P = 0.017) at a temperature of 15°C and humidity of 10% compared to a temperature of 30°C and humidity of 60%.

CONCLUSIONS

High ambient temperature resulted in a greater insulin peak effect compared to low ambient temperature, with the contribution of high relative humidity apparent only at high ambient temperature. This suggests that patients with type 1 diabetes mellitus who are entering higher environmental temperatures, with or without high humidity, could experience more hypoglycaemic events.

Insulin delivery methods: Past, present and future

Many patients with advanced type 2 diabetes mellitus (T2DM) and all patients with T1DM require insulin to keep blood glucose levels in the target range. The most common route of insulin administration is subcutaneous insulin injections. There are many ways to deliver insulin subcutaneously such as vials and syringes, insulin pens, and insulin pumps. Though subcutaneous insulin delivery is the standard route of insulin administration, it is associated with injection pain, needle phobia, lipodystrophy, noncompliance and peripheral hyperinsulinemia. Therefore, the need exists for delivering insulin in a minimally invasive or noninvasive and in most physiological way. Inhaled insulin was the first approved noninvasive and alternative way to deliver insulin, but it has been withdrawn from the market. Technologies are being explored to make the noninvasive delivery of insulin possible. Some of the routes of insulin administration that are under investigation are oral, buccal, nasal, peritoneal and transdermal. This review article focuses on the past, present and future of various insulin delivery techniques. This article has focused on different possible routes of insulin administration with its advantages and limitation and possible scope for the new drug development.

[New technologies in diabetology. How far are we from a closed loop?]

Today, assistive technologies are highly important in the treatment of diabetes, especially in the therapy of type 1 diabetes. The use of insulin pumps, for example, has become an established form of treatment. Modern insulin pumps offer various functions, such as different basal rate profiles, split delivery of the meal bolus, and integrated bolus calculators. Some pumps are additionally connected to a blood glucose meter or a continuous glucose-monitoring sensor. Several minimally invasive needle-type sensor systems for continuous tissue glucose monitoring are already available. Recent developments aim at increasing the functionality of insulin pumps and the improvements of sensors for continuous glucose monitoring. In addition, many research groups are working on closing the loop between these two components and thus developing an artificial pancreas, which automatically regulates insulin delivery. The first steps have already been taken and bolus calculators or sensor-augmented insulin pumps with suspension of insulin delivery are now available. Many experimental models show promising results. Prior to the implementation of a fully automated system for everyday use, however, partially automated systems that require user input are to be expected. This article aims at giving an overview of the current state of development in the field of diabetes technology.

Towards a Physiological Prandial Insulin Profile: Enhancement of Subcutaneously Injected Prandial Insulin Using Local Warming Devices

The need to develop an insulin delivery system that can closely mimic physiologically induced changes in prandial insulin release has been a major research target since the discovery of insulin. The challenges facing existing insulin delivery systems, related to relatively slow pharmacokinetics and pharmacodynamics, have been further highlighted by rapid advances in diabetes technology and progress in artificial pancreas research. Despite the growing interest in alternative routes of insulin administration, the subcutaneous route remains-at least for now-the preferred route for insulin administration. In this article, we review efforts aimed at developing subcutaneously injected ultrafast-acting insulin and measures aimed at enhancing insulin absorption, focusing on local warming devices.

Improved Postprandial Glucose Control Using the InsuPad Device in Insulin-Treated Type 2 Diabetes: Injection Site Warming to Improve Glycemic Control

BACKGROUND

Delays in the time-action profiles of premeal boluses of rapid-acting insulin analogs contribute to early postmeal hyperglycemia in patients with diabetes. We tested whether applying local heat to skin around the injection site to increase the rate of insulin absorption reduces postprandial hyperglycemia in patients with type 2 diabetes.

METHODS

Fourteen patients with type 2 diabetes (4 females; age 61.6 ± 8.4 years, HbA1c 8.42 ± 1.13%; BMI 29.10 ± 5.61 kg/m(2)) on intensified insulin therapy underwent 5-hour meal tolerance tests (MTTs) with a standardized liquid meal after an overnight fast on 2 study days. Subjects injected 0.2 U/kg of insulin aspart or lispro subcutaneously into the abdominal skin on both days with and without the use of the InsuPad device.

RESULTS

Following the premeal bolus injection of rapid-acting insulin analog, infusion site warming led to a rise in plasma insulin levels to peak concentrations that were significantly earlier than without skin warming (mean ± SD 52 ± 26.7 vs 80 ± 51.3 minutes, P < .005) as well as increase in plasma insulin levels during the first hour after injection (mean ± SD 63.5 ± 32.7 IU vs 48.0 ± 25.0 uU.min/ml, P = .019). As a result, the area under the curve of the postprandial glucose excursion during the first 2 hours (the primary study outcome) and the entire 5 hours after the meal were significantly reduced (P = .007 and P = .03, respectively) with skin warming around the injection site.

DISCUSSION AND CONCLUSIONS

Use of the InsuPad to increase the rate of insulin absorption provides an effective means to achieve better control of postmeal glucose excursions in type 2 diabetic patients receiving premeal injections of rapid-acting insulin analogs.

Improved pharmacokinetic and pharmacodynamic profiles of insulin analogues using InsuPatch, a local heating device

BACKGROUND

Previous studies have shown that heating the insulin injection site may accelerate insulin absorption. We investigated the pharmacological profile of insulin administered with InsuPatch, a local skin-heating device.

METHODS

In this randomized, crossover study carried out in 56 subjects with type 1 diabetes treated with insulin pump [mean age 32 ± 13.5 years; 23 women; HbA1c :7.8 ± 0.9% (62 ± 10 mmol/mol) (mean+/-standard deviation)]. Euglycemic glucose clamps were performed after administration of 0.15 units/kg of short-acting insulin analogues. Each subject underwent three clamp procedures: two with the InsuPatch device (day 1 and day 3) and one without the device (day 1 control). The primary endpoints were the following: (1) the change in the area under the curve (AUC) of insulin during the first 60 min post-insulin bolus on day 1 with the InsuPatch device versus day 1 control and (2) parameters to assess the safety of using the device.

RESULTS

The area under the curve of insulin during the initial 60 min (insulin AUC(0-60)) after insulin bolus was increased by 29.7 ± 7% on day 1 InsuPatch versus day 1 control (p < 0.01). Maximal post-insulin bolus concentration was 57 mU/L on day 1 InsuPatch versus 47.6 mU/L on day 1 control (p < 0.01). On day 3 InsuPatch, insulin AUC(0-60) was increased by 27.9 ± 72% versus day 1 InsuPatch (p < 0.01). Maximal insulin concentration was 70.4 mU/L versus 57 mU/L, respectively (p = 0.05).

CONCLUSIONS

The use of the heating device upon administration of short-acting insulin analogues in pump-treated type 1 diabetic patients was found to enhance insulin absorption. This heating device may therefore serve to achieve better meal insulin coverage.

The Barmer study: impact of standardized warming of the injection site to enhance insulin absorption and reduce prandial insulin requirements and hypoglycemia in obese patients with diabetes mellitus

BACKGROUND

The primary objective of this prospective controlled study was to investigate the impact of standardized injection-site warming on prandial rapid acting insulin dose and glycemic control when studied under real-world conditions.

METHODS

All 145 participating patients (51 female, 94 male, 13 type 1 and 132 type 2 patients, age: 61.6 ± 8.4 yrs, HbA1c: 7.19 ± 0.50%) were treated with intensive insulin glargine and short-acting insulin analog therapy. After a 4 week treatment optimization run-in period, patients were randomized to continue therapy for three months without (control) or with a local injection-site warming device (InsuPad * ). Observation parameters included HbA1c, insulin dose, frequency of hypoglycemia, body weight and adverse events.

RESULTS

HbA1c improved in both arms until study end (control group: 6.3 ± 0.5%; injection-site warming device: 6.3 ± 0.5%; both p < 0.001 vs. baseline). To achieve this good control, patients in the control group needed to increase the daily prandial insulin dose by 8.1% (from 66 ± 31 U to 71 ± 38 U, p < 0.05) with stable basal insulin requirements. Patients who used the injection-site warming device required less prandial insulin (70 ± 43 U to 55 ± 34 U; -19%, p < 0.001) and slightly more basal insulin (+3.9%). Total daily insulin dose increased in the control group (+3.7%) and decreased with warming device use (-8.6%, p < 0.001). The number of hypoglycemic events (<63 mg/dL) during the observation period was higher in the control group (6.2 ± 9.9/patient vs. injection-site warming device: 3.3 ± 4.8/patient, p < 0.05). Main study limitations can be seen in the open label design reliability of the collected dose information and the very obese patient cohort.

CONCLUSION

When treating obese patients to target with insulin therapy, use of an injection-site warming device for 3 months resulted in a lower frequency of hypoglycemic events and a reduction in prandial insulin analog requirements. If these results are confirmed in other patient populations, an injection-site warming device may be useful in achieving treatment targets with a safer and more efficient basal bolus therapy in insulin-treated patients with type 1 and type 2 diabetes.

Increasing local blood flow by warming the application site: beneficial effects on postprandial glycemic excursions

The absorption profile of rapid-acting insulin analogs delivered subcutaneously is slow compared with physiological insulin. Shorter time to peak and shorter duration of insulin action are important steps toward reducing high postprandial blood glucose concentrations in diabetes therapy and are critical for the development of a closed-loop insulin delivery system. Many attempts have been made to develop more rapid-acting insulins. Since the 1950s, different approaches, such as jet injectors and sprinkler needles, which try to increase the absorption areas of injected insulin, have been developed; however, none of them are commonly used in diabetes therapy. Massage and heat increase tissue blood perfusion and, thereby, the absorption of subcutaneously applied insulin. The main focus of this article is a novel device that allows local application of heat to human skin. The device can be connected to a regular insulin pump. This device could demonstrate a significant effect on insulin absorption and postprandial glucose excursions in multiple clinical trials.