Development of the Extended Infusion Set and Its Mechanism of Action

Continuous subcutaneous insulin infusion (CSII, or insulin pump) and continuous glucose monitoring (CGM) sensors have been increasingly used and associated with improved glycemic control by people with type 1 diabetes and insulin-requiring type 2 diabetes. Commonly used infusion sets in most CSII systems are limited to a wear time of 3 days. In contradistinction, CGM sensors are currently approved for seven and more days of wear. With the motivation to provide a 7-day infusion set that matches the CGM wear time and to improve patient experience, the recently CE-marked and FDA 510k-cleared Medtronic extended infusion set (EIS) was designed.s The EIS offers enhanced new features that include use for up to 7 days, improved convenience, comfort, and better quality of life for insulin pump users.

Advances in Insulin Infusion Set in the New Era of Automated Insulin Delivery: A Systematic Review

INTRODUCTION

Automated insulin delivery (AID) has become a well-known research topic devoted to achieving better glycemic outcomes. AID systems consist primarily of three components: the continuous glucose monitoring system, the insulin delivery system, either tethered or patch pump, and the control system (algorithm). A key component in the tethered pump AID system is the insulin infusion set (IIS). This Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) study was conducted to evaluate the IIS evolution in the era of AID and to provide future perspectives of IIS clinical use.

METHODS

Literature searches for articles published from January 2016 to July 2022 were performed in Embase/Medline and PubMed. Data were extracted following PRISMA guidelines. Primary meta-analysis outcomes were IIS wear duration, total daily dose of insulin, and IIS failure reasons/modes.

RESULTS

We identified 387 publications, of which 15 eligible studies compared various IISs comprising over 1400 participants and >53 000 wears. Half of the studies published in 2022 were focused on extended IISs designed for wear durations of seven days or more. Three clinical trials have demonstrated the safe use of extended IISs to seven days of wear in individuals with type 1 diabetes, and two also demonstrated good glycemic control throughout the seven-day use.

CONCLUSIONS

Research in insulin infusion technology has increased in the last six years, and extended IISs have demonstrated improved overall performance, particularly in duration of wear. Paths for future products are discussed with an emphasis on understanding the existing barriers related to both technical and nontechnical issues.

Evaluation of Extended Infusion Set Performance in Adults with Type 1 Diabetes: Infusion Set Survival Rate and Glycemic Outcomes from a Pivotal Trial

Background: Standard insulin infusion sets (IISs) are to be replaced every 2 to 3 days to avoid complications and diabetic ketosis due to set failure. This pivotal trial evaluated the safety and performance of a new extended-wear infusion set (EIS) when used for 7 days by adults with type 1 diabetes (T1D). Methods: This single-arm, nonrandomized trial enrolled adults (18-80 years of age) with T1D, who used their own MiniMed™ 670G system with insulin lispro or insulin aspart and the EIS for up to 7 days, across 12 consecutive wears. Safety endpoints included incidence of serious adverse events (SAEs), serious adverse device effects (SADEs), unanticipated adverse device effects (UADEs), severe hypoglycemia (SevHypo), severe hyperglycemia (SevHyper), diabetic ketoacidosis (DKA), and skin infection. The EIS failure rate due to unexplained hyperglycemia (i.e., suspected occlusion), the overall EIS survival rate, glycemic control outcomes (i.e., A1C, mean sensor glucose and time spent in established glucose ranges), total daily insulin delivered, and satisfaction with the EIS were determined. Results: The intention to treat population (n = 259, 48% men, 45.0 ± 14.1 years) wore a total of 3041 EIS devices. No SADE, UADE, or DKA events was reported. Overall rates of SAEs, SevHypo, SevHyper, and skin infection were 3.8, 2.5, 104.1, and 20.1 events per 100 participant-years. The rate of EIS failure due to unexplained hyperglycemia at the end of day 7 was 0.1% (95% confidence interval [CI]: 0.03-0.51) and 0.4% (95% CI: 0.16-1.00) for insulin lispro and aspart use, respectively. Overall EIS survival rate at the end of day 7 was 77.8% (95% CI: 76.2-79.3), glycemic control did not change, and participants reported greater satisfaction with the EIS compared with standard IISs worn before the study (P < 0.001). Conclusions: This investigation demonstrates that the EIS, when worn for up to 7 days, was safe and rated with high satisfaction, without adversely affecting glycemic control in adults with T1D. Clinical Trial Registration number: NCT04113694 (https://clinicaltrials.gov/ct2/show/NCT04113694).

Improving the Patient Experience With Longer Wear Infusion Sets Symposium Report

Continuous subcutaneous insulin infusion (CSII) therapy is becoming increasingly popular. CSII provides convenient insulin delivery, precise dosing, easy adjustments for physical activity, stress, or illness, and integration with continuous glucose monitors in hybrid or other closed-loop systems. However, even as insulin pump hardware and software have advanced, technology for insulin infusion sets (IISs) has stayed relatively stagnant over time and is often referred to as the "Achilles heel" of CSII. To discuss barriers to insulin pump therapy and present information about advancements in, and results from clinical trials of extended wear IISs, Diabetes Technology Society virtually hosted the "Improving the Patient Experience with Longer Wear Infusion Sets Symposium" on December 1, 2021. The symposium featured experts in the field of IISs, including representatives from Steno Diabetes Center Copenhagen, University of California San Francisco, Stanford University, Medtronic Diabetes, and Science Consulting in Diabetes. The webinar's seven speakers covered (1) advancements in insulin pump therapy, (2) efficacy of longer wear infusion sets, and (3) innovations to reduce plastics and insulin waste.

Advances in Insulin Pump Infusion Sets Symposium Report

Continuous subcutaneous insulin infusion (CSII) is becoming increasingly used for achieving target glycemic control as well as providing flexibility in lifestyle. In a widely used version of CSII, the insulin pump itself is attached to one end of an insulin infusion set (IIS), which delivers insulin via a thin flexible plastic tube to the patient's body via a cannula or needle that is inserted under the skin at the other end of the IIS. Despite the increased use of CSII by patients with diabetes, there have been few recent advances in IIS technology, especially when compared to the many recent advances made in insulin pump technology and in insulin pharmacokinetics. To discuss recent developments in, and future plans for IIS development, Diabetes Technology Society virtually hosted the Advances in Insulin Pump Infusion Sets Symposium on December 1, 2020. This symposium featured experts in the field of IISs, including representatives from Medtronic and ConvaTec (which are two manufacturers that are currently developing IISs), Stanford University, Steno Diabetes Center Copenhagen, and Science Consulting in Diabetes. The webinar's six speakers covered (1) patient burden, (2) extended wear technology, and (3) future directions in IIS development.

The improved survival rate and cost-effectiveness of a 7-day continuous subcutaneous insulin infusion set

AIMS

The purpose of this article is to compare the insulin cost-savings of the Medtronic Extended Infusion Set (or EIS, a.k.a. Extended Wear Infusion Set) designed and labeled for up to 7-day use with rapid-acting insulins to the current standard of care, 2- to 3-day infusion sets.

METHODS

There are three major improvements (reducing insulin waste, plastic waste, and adverse events) with the extended duration of infusion set wear. This analysis focuses on cost savings from reduced insulin wastage during set changes. Studies published on insulin infusion set survival and EIS clinical trial data (NCT04113694) were used to estimate device lifetime performance using a Markov chain Monte Carlo model, including the assessment of adverse effects and device failure. Total costs associated with infusion set change or failure were systematically found in published literature or estimated based on physical usage, and the direct impact on insulin costs was calculated.

RESULTS

Based on the model and clinical data, EIS users can expect to change their infusion sets about 75 fewer times than standard set users each year. The costs related to unrecoverable insulin during an infusion set and reservoir change in the US were estimated to range from $19.79 to $22.48, resulting in approximately $1324 to $1677 in annual cost-savings for the typical user from minimizing insulin wastage.

LIMITATIONS

The study only assessed devices used within a monitored setting, that is, clinical trials. In addition, the variability associated with healthcare standards and costs and individual treatment variability including insulin dosages, contribute to the uncertainties with the calculations.

CONCLUSIONS

Our analysis demonstrates that by extending the duration of infusion set wear, there may be substantial cost savings by reducing insulin wastage.

Male erectile dysfunction: therapy and drug delivery

Finding an ideal chemical agent or a user-friendly delivery system for the treatment of male erectile dysfunction (MED) has been the goal of several research groups. The most suitable therapy for erectile dysfunction (ED) in man would involve a chemical that acts directly or indirectly on the penis and assures erection without any side effects. The understanding of ED has grown tremendously over the last decade and has been accompanied by an impressive proliferation of new therapies, ranging from traditional therapeutic agents to novel agents and drug delivery systems. Before Viagra, the most effective therapies involved injecting drugs directly into the base of the penis and inserting suppositories into the urethra, but these were too invasive to achieve great popularity. Although ED was not an area of pharmaceutical research that many companies were focused on, the success of Viagra has shown that there is a huge market opportunity for this indication. Financial analysts project a worldwide market of approximately $2 billion for oral ED treatments. This review presents a general overview of the present state as well as the future directions of research to treat MED.

DMP-504 (DuPont Pharmaceuticals Co)

DMP-504 is a novel hydrogel bile acid sequestrant being developed by DuPont for the potential treatment of primary moderate hypercholesterolemia. It is in phase III trials. Equilibrium binding studies coupled with computer simulation of human bile flow predict that DMP-504 could be 3- to 4-fold more potent than cholestyramine in a clinical setting. Preclinical pharmacology studies demonstrate DMP-504 is 6-fold more potent than cholestyramine at decreasing serum cholesterol in hamsters. Clinical studies, at doses ranging from 0.9 to 7.2 g/day, indicate that DMP-504 is well tolerated and decreases LDL-cholesterol by up to 34%. As of June 1997, DuPont was seeking to outlicense DMP-504, which will be marketed in an easy-to-swallow, non-gritty tablet.

Indirect atomic absorption spectrometric determination of sulfate in human blood serum

An indirect method for the determination of sulfate by atomic absorption spectrometry (AAS) is described. Sulfate forms a stable ion-association complex, [Cu(neocuproine)2]2+(SO4(2-)), in neutral medium, which can be extracted into isobutyl methyl ketone in the presence of a polar medium (methanol) with an efficiency higher than 98.0% and the extract can be analysed directly for copper (and hence indirectly for sulfate) by AAS. Measurement of the copper atomic absorption signal from the organic phase allows the indirect determination of 0.14-1.12 micrograms ml-1 of sulfate, giving a 450-fold increase in sensitivity over the conventional method of precipitation with barium. The limit of detection (3 sigma) is 3.2 ng ml-1 which is better than that of ion chromatography (0.15 micrograms ml-1). Indirect AAS allows the accurate assay of inorganic sulfate anion in biological fluids and tissues. The sulfate concentration determined by the proposed method in human blood serum (n = 6 in each instance) was 35.4-43.3 micrograms ml-1 in normal persons, 50.3-62.5 micrograms ml-1 in jaundice patients and 83.3-155.6 micrograms ml-1 in diabetic patients. A good correlation between measured sulfate and the sulfate added to blood serum was obtained.

Indirect determination of free cyanide in industrial waste effluent by atomic absorption spectrometry

An indirect method is described for the determination of free cyanide in industrial waste effluent samples by atomic absorption spectrometry (AAS). In an alkaline medium, cyanide forms a stable complex species [Cu(BPTC)(CN)] (BPTC = 2-benzoylpyridine thiosemicarbazone), which can be extracted into a mixture of isobutyl methyl ketone-isopentyl alcohol (7 + 1) with an efficiency of greater than 98.5%. The extract can be analysed directly for copper (and hence indirectly for cyanide) by flame AAS. The calibration graph is linear up to 5.7 micrograms of cyanide per millilitre of solvent mixture and the limit of detection is 4.8 ng ml-1. A large number of foreign ions were found not to interfere with the proposed method.