Novel insulins: expanding options in diabetes management

Effect of insulin analogues on phosphatidyl inositol-3 kinase/Akt signalling in INS-1 rat pancreatic derived β-cells

CONTEXT

Insulin analogues are largely used for the treatment of diabetic patients, but concerns have been raised about their mitogenic/anti-apoptotic potential. It is therefore important to evaluate these analogues in different cell systems.

OBJECTIVE

The aim of this work was to establish the pharmacological profiles of insulin analogues towards PI-3 kinase/Akt pathway in INS-1 β-pancreatic cells.

METHODS

Bioluminescence Resonance Energy Transfer (BRET), in cell western and caspase 3/7 assays, was used to study the effects of ligands.

RESULTS

Among the five analogues evaluated, only glargine stimulated PI-3 kinase/Akt pathway with higher efficiency than insulin, whereas glargine's metabolite M1 was less efficient. However, glargine did not show higher anti-apoptotic efficiency than insulin.

CONCLUSION

Glargine was more efficient than insulin for the activation of PI-3 kinase/Akt pathway, but not for the inhibition of caspase 3/7 activity. Moreover, glargine's metabolite M1 displayed lower efficiency than insulin towards PI-3 kinase/Akt activation and caspase 3/7 inhibition.

Why most oral insulin formulations do not reach clinical trials

Oral insulin able to induce an efficient antihyperglycemic effect either to replace or complement diabetes mellitus therapy is the major goal of health providers, governments and diabetic patients. Oral therapy is associated not only with the desire to exclude needles from the daily routine of diabetic patient but also with the physiological provision of insulin they would get. Despite numerous efforts over the past few decades to develop insulin delivery systems, there is still no commercially available oral insulin. The reasons why the formulations developed to administer insulin orally fail to reach clinical trials are critically discussed in this review. The principal features of nanoformulations used so far are also addressed as well as the undergoing clinical trials.

Direct comparison of radioimmunoassay and LC–MS/MS for PK assessment of insulin glargine in clinical development

Background: A direct comparison of radioimmunoassay (RIA) and LC–MS/MS for insulin glargine quantification in human plasma is provided. Results: Compared with the RIA, the LC–MS/MS assay exhibited comparable/improved sensitivity (LLOQ at 0.1 ng/ml [˜16.7 pM or 2.8 μU/ml] for glargine and its metabolites M1 and M2, respectively) and ruggedness. Most importantly, it demonstrated a superior specificity advantage against the interference from endogenous insulin, exogenous insulin analogs (e.g., Novolog®, Humalog® or Levemir®, routine treatment for diabetes mellitus) and potentially pre-existing anti-insulin antibodies in patient samples. The data obtained from diabetic patients suggested the LC–MS/MS assay substantially improved pharmacokinetic characterization of glargine. Conclusion: LC–MS/MS overcame common limitations of RIA, and provided critically needed specificity to support glargine clinical development, without sacrificing assay sensitivity and ruggedness.

Biotechnology and genetic engineering in the new drug development. Part I. DNA technology and recombinant proteins

Pharmaceutical biotechnology has a long tradition and is rooted in the last century, first exemplified by penicillin and streptomycin as low molecular weight biosynthetic compounds. Today, pharmaceutical biotechnology still has its fundamentals in fermentation and bioprocessing, but the paradigmatic change affected by biotechnology and pharmaceutical sciences has led to an updated definition. The biotechnology revolution redrew the research, development, production and even marketing processes of drugs. Powerful new instruments and biotechnology related scientific disciplines (genomics, proteomics) make it possible to examine and exploit the behavior of proteins and molecules. Recombinant DNA (rDNA) technologies (genetic, protein, and metabolic engineering) allow the production of a wide range of peptides, proteins, and biochemicals from naturally nonproducing cells. This technology, now approximately 25 years old, is becoming one of the most important technologies developed in the 20(th) century. Pharmaceutical products and industrial enzymes were the first biotech products on the world market made by means of rDNA. Despite important advances regarding rDNA applications in mammalian cells, yeasts still represent attractive hosts for the production of heterologous proteins. In this review we describe these processes.

Effect of insulin analogues on insulin/IGF1 hybrid receptors: increased activation by glargine but not by its metabolites M1 and M2

Background

In diabetic patients, the pharmacokinetics of injected human insulin does not permit optimal control of glycemia. Fast and slow acting insulin analogues have been developed, but they may have adverse properties, such as increased mitogenic or anti-apoptotic signaling. Insulin/IGF1 hybrid receptors (IR/IGF1R), present in most tissues, have been proposed to transmit biological effects close to those of IGF1R. However, the study of hybrid receptors is difficult because of the presence of IR and IGF1R homodimers. Our objective was to perform the first study on the pharmacological properties of the five marketed insulin analogues towards IR/IGF1R hybrids.

Methodology

To study the effect of insulin analogues on IR/IGF1R hybrids, we used our previously developed Bioluminescence Resonance Energy Transfer (BRET) assay that permits specific analysis of the pharmacological properties of hybrid receptors. Moreover, we have developed a new, highly sensitive BRET-based assay to monitor phophatidylinositol-3 phosphate (PIP₃) production in living cells. Using this assay, we performed a detailed pharmacological analysis of PIP₃ production induced by IGF1, insulin and insulin analogues in living breast cancer-derived MCF-7 and MDA-MB231 cells.

Results

Among the five insulin analogues tested, only glargine stimulated IR/IGF1R hybrids with an EC50 that was significantly lower than insulin and close to that of IGF1. Glargine more efficiently stimulated PIP₃ production in MCF-7 cells but not in MDA-MB231 cells as compared to insulin. In contrast, glargine metabolites M1 and M2 showed lower potency for hybrid receptors stimulation, PIP₃ production, Akt and Erk1/2 phosphorylation and DNA synthesis in MCF-7 cells, compared to insulin.

Conclusion

Glargine, possibly acting through IR/IGF1R hybrids, displays higher potency, whereas its metabolites M1 and M2 display lower potency than insulin for the stimulation of proliferative/anti-apoptotic pathways in MCF-7 cells.

Pharmacokinetics and pharmacodynamics of insulin analogs in special populations with type 2 diabetes mellitus

Introduction

The goal of insulin therapy in patients with either type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM) is to match as closely as possible normal physiologic insulin secretion to control fasting and postprandial plasma glucose. Modifications of the insulin molecule have resulted in two long-acting insulin analogs (glargine and detemir) and three rapid-acting insulins (aspart, lispro, and glulisine) with improved pharmacokinetic/pharmacodynamic (PK/PD) profiles. These agents can be used together in basal-bolus therapy to more closely mimic physiologic insulin secretion patterns.

Methods

This study reviews effects of the multiple demographic and clinical parameters in the insulin analogs glargine, detemir, lispro, aspart, and glulisine in patients with T2DM. A search was conducted on PubMed for each major topic considered (effects of injection site, age, race/ethnicity, obesity, renal or hepatic dysfunction, pregnancy, exercise, drug interactions) using the topic words and name of each type of insulin analog. Information was also obtained from the prescribing information for each insulin analog.

Results

The PK/PD profiles for insulin analogs may be influenced by many variables including age, weight, and hepatic and renal function. However, these variables do not have equivalent effects on all long-acting or rapid-acting insulin analogs.

Conclusion

Rapid-acting and long-acting insulin analogs represent major advances in treatment for patients with T2DM who require insulin therapy. However, there are potentially important PK and PD differences between the two long-acting agents and among the three rapid-acting insulin analogs, which should be considered when designing treatment regimens for special patient groups.

Basal insulin: physiology, pharmacology, and clinical implications

Primary goals in the treatment of type 2 diabetes mellitus (T2DM) include lowering blood glucose levels sufficiently to prevent micro- and macrovascular complications while limiting side effects, such as hypoglycemia and excessive weight gain. Patients with T2DM are typically treated initially with oral antidiabetes agents; however, as the disease progresses, most will require insulin to maintain glycemic control. Often insulin therapy is initiated with basal insulin, and the objective of this article is to present the conceptual aspects of basal insulin therapy and use these concepts to illustrate important clinical aspects. This will be accomplished within a broader contextual discussion of the normal physiologic patterns of insulin secretion, which consist of sustained levels of basal insulin production throughout the day, superimposed with bursts of insulin secretion following a meal (termed bolus or prandial insulin secretion) that slowly decay over 1 to 3 hours. Long-acting basal insulin analogs form a key component of basal-bolus therapy and provide basal support for patients with T2DM. Insulin therapy is often initiated with basal insulin, and newer long-acting analogs, such as insulin glargine and insulin detemir, provide steady, reliable basal insulin coverage in addition to significant advantages over traditional long-acting insulins. This article will integrate conceptual aspects of basal insulin therapy in the context of physiology, molecular pharmacology, and clinical implications of modern basal insulin analogs to provide a foundational understanding of basal insulin biology and physiology.

Injectable thermally responsive mucoadhesive gel for sustained protein delivery

Poloxamer thermoresponsive gels are widely explored in controlled drug delivery. Nevertheless, these gels possess inadequate mechanical properties, poor bioadhesiveness, and high permeability to water. To overcome these issues, we blended mucoadhesive hyaluronic acid (HA) with poloxamer analogs. This study aimed to investigate the features affecting the microscopic properties of the gels, which determine their macroscopic properties and capability to control/sustain protein release. Results showed that HA hampers water-poloxamer interactions, thus, strongly influencing physicochemical properties of poloxamer gels. This leads to gels with improved mechanical properties in which the diffusion kinetics of macromolecular active molecules are drastically slowed down. Poloxamer-HA gels can sustain the delivery of proteins, such as insulin, and may allow the modulation of its release kinetics by modifying HA content within the gels in the administration sites in which the active molecule release mechanism is mainly governed by its diffusion.

Outcomes of clinical nurse specialist-initiated system-level standardized glucose management

The purpose of this quality improvement project was to determine if the use of standardized insulin orders versus the use of nonstandardized insulin orders improved glucose results in a hospital's critical care unit. A clinical nurse specialist-led interdisciplinary team developed standardized insulin orders with the goal of improving glucose control. Of the 570 patients admitted from July to September 2006, 124 met glucose criteria to use standardized insulin orders. A total of 331 individual glucose results from 16 patients reviewed demonstrated a difference in mean and median when standardized orders were used versus when they were not used to control glucose. A mean glucose of 175 mg/dL and median glucose of 149 mg/dL were the outcomes when standardized insulin orders were used versus a mean glucose of 206 mg/dL and median glucose of 190 mg/dL when standardized orders were not used. System change efforts to improve glucose control resulted in improved staff nurse empowerment, improved provider knowledge of glucose control methods, and improved patient glucose control in this Midwestern hospital.

New Insulin Analogues and Perioperative Care of Patients with Type 1 Diabetes

While insulin remains the mainstay of managing type 1 diabetes, much has changed over the last 15 years. These changes should help in managing patients with type 1 diabetes during the perioperative period. More flexible insulin therapy has three components: 1) basal, 2) prandial and 3) corrective. Many patients, particularly younger patients, are using genetically modified recombinant human insulin analogues. Two of these analogues, aspart and lispro insulin, are rapid-acting with faster onset and offset than subcutaneous regular insulin, allowing both prandial and corrective boluses. Other insulin analogues, particularly glargine and possibly detemir, have a flat profile of up to 24 hours, providing improved basal insulin delivery. Basal insulin can also be provided by a continuous subcutaneous infusion of rapid-acting insulin via a computerised pump that also provides boluses on demand. There is little evidence to help choose the best management of patients with type 1 diabetes during surgery. Some authors still recommend glucose-potassium-insulin infusions for all patients with type 1 diabetes. We challenge this approach, given the flexibility of the newer insulin analogues and delivery systems. We suggest that for many procedures, patients’ usual regimens can be maintained in the perioperative period, providing less disruption and, possibly, greater safety. Both hyperglycaemia and hypoglycaemia reflect poor management: we suggest a target glucose range of 5 to 10 mmol/l. The importance of frequently measuring blood glucose and appropriate responses cannot be overemphasised.

Impact of Absorption and Transport on Intelligent Therapeutics and Nano-scale Delivery of Protein Therapeutic Agents

The combination of materials design and advances in nanotechnology has led to the development of new therapeutic protein delivery systems. The pulmonary, nasal, buccal and other routes have been investigated as delivery options for protein therapy, but none result in improved patient compliances and patient quality of life as the oral route. For the oral administration of these new systems, an understanding of protein transport is essential because of the dynamic nature of the gastrointestinal tract and the barriers to transport that exist.Models have been developed to describe the transport between the gastrointestinal lumen and the bloodstream, and laboratory techniques like cell culture provide a means to investigate the absorption and transport of many therapeutic agents. Biomaterials, including stimuli-sensitive complexation hydrogels, have been investigated as promising carriers for oral delivery. However, the need to develop models that accurately predict protein blood concentration as a function of the material structure and properties still exists.

Management of progressive type 2 diabetes: role of insulin therapy

Insulin is an effective treatment for achieving tight glycemic control and improving clinical outcomes in patients with diabetes. While insulin therapy is required from the onset of diagnosis in type 1 disease, its role in type 2 diabetes requires consideration as to when to initiate and advance therapy. In this article, we review a case study that unfolds over 5 years and discuss the therapeutic decision points, initiation and advancement of insulin regimens, and analyze new data regarding the advantages and disadvantages of tight management of glucose levels.

WITHDRAWN: Inhaled insulin in diabetes mellitus

BACKGROUND

Insulin therapy often relies on multiple daily injections of insulin. However this is a considerable burden to many people with diabetes and adherence to such an insulin regimen can be difficult to maintain, hence compromising optimal glycaemic control. Also, short acting injected insulin is absorbed more slowly than insulin released by the normal pancreas in response to a meal. Inhaled insulin has the potential to reduce the number of injections to perhaps one long-acting insulin per day, and provide a closer match to the natural state, by more rapid absorption from the lung.

OBJECTIVES

To compare the efficacy, adverse effects and patient acceptability of inhaled versus injected insulin.

SEARCH STRATEGY

A sensitive search strategy for randomised controlled or cross-over trials was combined with key terms for inhaled insulins. Databases searched were: The Cochrane Library, MEDLINE, PubMed, EMBASE, Science Citation Index, BIOSIS, Web of Science Proceedings, National Research Register UK, Current Controlled Trials, ClinicalTrials.gov, Conference Papers Index, LexisNexis, and web sites of the ADA and EASD were searched for recent meeting abstracts. Reference lists and journals were handsearched. There were no language restrictions on searching. Manufacturers of inhaled insulin were also contacted. Date of last search October 2002.

SELECTION CRITERIA

Only randomised controlled trials with parallel groups or controlled cross-over trials, including type 1 or type 2 diabetic patients of any age treated with insulin, were considered eligible. The minimum trial duration considered was 10 weeks, as this is the time taken for glycated haemoglobin to reliably reflect changes in glycaemic control.

DATA COLLECTION AND ANALYSIS

Trial selection and evaluation of study quality was performed independently by two reviewers. The quality of reporting of each trial was assessed according to a modification of the criteria outlined in Centre for Reviews and Dissemination (CRD) Report 4, Spitzer; and Jadad.

MAIN RESULTS

Six randomised controlled trials were found and the overall number of participants was 1191. Three trials included patients with type 1 diabetes and three with type 2 diabetes. Three trials had a duration of 24 weeks, and three of 12 weeks. All were open label. There was insufficient information to determine the study quality. Results for HbA1c were similar for all trials, in that all showed comparable glycaemic control for inhaled insulin compared to an entirely subcutaneous regimen. All trials that reported patient satisfaction and quality of life showed that these were significantly greater in the inhaled insulin group. Overall there was no difference in total hypoglycaemic episodes between the groups, but one trial showed a statistically significant increase in severe hypoglycaemic episodes for the inhaled insulin group. No adverse pulmonary effects were observed in any of the studies, but longer follow-up will be required to be sure that there are no adverse side-effects. Cavets include: few studies published in full (so quality could not be assessed), and only two studies used the same basal regimen in both the inhaled and injected groups.

AUTHORS' CONCLUSIONS

Inhaled insulin taken before meals, in conjunction with an injected basal insulin, has been shown to maintain glycaemic control comparable to that of patients taking multiple daily injections. The key benefit appears to be that patient satisfaction and quality of life are significantly improved, presumably due to the reduced number of daily injections required. However, the patient satisfaction data is based on five trials, of which only two have been published in full; also the three trials containing quality of life data are all only published in abstract form at present. In addition, longer term pulmonary safety data are still needed. Also, the lower bioavailability, and hence higher doses of inhaled insulin required, may make it less cost-effective than injected insulin.

Adjust to target in type 2 diabetes: comparison of a simple algorithm with carbohydrate counting for adjustment of mealtime insulin glulisine

OBJECTIVE

Carbohydrate counting is an effective approach to mealtime insulin adjustment in type 1 diabetes but has not been rigorously assessed in type 2 diabetes. We sought to compare an insulin-to-carbohydrate ratio with a simple algorithm for adjusting the dose of prandial insulin glusiline.

RESEARCH AND DESIGN METHODS

This 24-week, multicenter, randomized, controlled study compared two algorithms for adjusting mealtime (glulisine) insulin along with a standard algorithm for adjusting background (glargine) insulin in 273 intent-to-treat patients with type 2 diabetes. Glulisine and glargine were adjusted weekly in both groups based on self-monitored blood glucose (SMBG) results from the previous week. The simple algorithm group was provided set doses of glulisine to take before each meal. The carbohydrate counting (carb count) group was provided an insulin-to-carbohydrate ratio to use for each meal and adjusted their glulisine dose based on the amount of carbohydrate consumed.

RESULTS

A1C levels at week 24 were 6.70% (simple algorithm) and 6.54% (carb count). The respective mean A1C changes from baseline to 24 weeks were -1.46 and -1.59% (P = 0.24). A1C <7.0% was achieved by 73.2% (simple algorithm) and 69.2% (carb count) (P = 0.70) of subjects; respective values for A1C <6.5% were 44.3 and 49.5% (P = 0.28). The total daily dose of insulin was lower, and there was a trend toward less weight gain in carb count group patients. Severe hypoglycemia rates were low and equal in the two groups.

CONCLUSIONS

Weekly basal-bolus insulin adjustments based on premeal and bedtime glucose patterns resulted in significant reductions in A1C. Having two effective approaches to delivering and adjusting rapid-acting mealtime insulin may increase physicians' and patients' willingness to advance therapy to a basal-bolus insulin regimen.

Development of a clinical type 1 diabetes metabolic system model and in silico simulation tool

OBJECTIVES

The goal of this study was to develop a system model of type 1 diabetes for the purpose of in silico simulation for the prediction of long-term glycemic control outcomes.

METHODS

The system model was created and identified on a physiological cohort of virtual type 1 diabetes patients (n = 40). Integral-based identification was used to develop (n = 40) insulin sensitivity profiles.

RESULTS

The n = 40 insulin sensitivity profiles provide a driving input for virtual patient trials using the models developed. The identified models have a median (90% range) absolute percentage error of 1.33% (0.08-7.20%). The median (90% range) absolute error was 0.12 mmol/liter (0.01-0.56 mmol/liter). The model and integral-based identification of SI captured all patient dynamics with low error, which would lead to more physiological behavior simulation.

CONCLUSIONS

A simulation tool incorporating n = 40 virtual patient data sets to predict long-term glycemic control outcomes from clinical interventions was developed based on a physiological type 1 diabetes metabolic system model. The overall goal is to utilize this model and insulin sensitivity profiles to develop and optimize self-monitoring blood glucose and multiple daily injection therapy.

In silico simulation of long-term type 1 diabetes glycemic control treatment outcomes

OBJECTIVES

The goals of this study were to develop (1) a safe and effective protocol for the clinical control of type 1 diabetes using conventional self-monitoring blood glucose (SMBG) measurements and multiple daily injections with insulin analogues, and (2) an in silico simulation tool of type 1 diabetes to predict long-term glycemic control outcomes of clinical interventions.

METHODS

The virtual patient method was used to develop a simulation tool for type 1 diabetes using data from a type 1 diabetes patient cohort (n = 40). The tool was used to test the adaptive protocol (AC) and a conventional intensive insulin therapy (CC) against results from a representative control cohort. Optimal and suboptimal basal insulin replacements were evaluated as a function of SMBG frequency in conjunction with the (AC and CC) prandial control protocols.

RESULTS

In long-term glycemic control, the AC protocol significantly decreased hemoglobin A1c in conditions of suboptimal basal insulin replacement for SMBG frequencies > or = 6/day, and reduced the occurrence of mild and severe hypoglycemia by 86-100% over controls, over all SMBG frequencies in conditions of optimal basal insulin.

CONCLUSIONS

A simulation tool to predict long-term glycemic control outcomes from clinical interventions has been developed to test a novel, adaptive control protocol for type 1 diabetes. The protocol is effective and safe compared to conventional intensive insulin therapy and controls. As fear of hypoglycemia is a large psychological barrier to glycemic control, the AC protocol may represent the next evolution of intensive insulin therapy to deliver increased glycemic control with increased safety. Further clinical or experimental validation is needed to fully prove the concept.

Improved glycaemic control of thrice-daily biphasic insulin aspart compared with twice-daily biphasic human insulin; a randomized, open-label trial in patients with type 1 or type 2 diabetes

AIM

This trial evaluated the potential for improving glycaemic control by intensifying a conventional twice-daily therapy with premixed human insulin (HI) to a thrice-daily regimen using premixed formulations of biphasic insulin aspart (BIAsp) in patients with type 1 or type 2 diabetes.

METHODS

This was a multicentre, open-label, parallel group trial. After a 4-week run-in period, patients were randomized 1 : 1 to 16 weeks of treatment. A total of 748 patients were screened, 664 were exposed to trial drug and 604 completed the trial.

RESULTS

Haemoglobin A(1c), the primary efficacy endpoint, was shown to be significantly lower for the BIAsp treatment group compared with the biphasic HI (BHI) 30 group [estimated mean difference: -0.32, 95% confidence interval (CI) (-0.48; -0.16), p = 0.0001]. The average blood glucose level was significantly lower in the BIAsp group [estimated mean difference: -0.79, 95% CI (-1.17; -0.40), p = 0.0001]. There were few major hypoglycaemic episodes, 11 in the BIAsp group and 7 in the BHI 30 group. Although intensification of insulin therapy with BIAsp three times a day was associated with a higher risk of minor hypoglycaemia (relative risk = 1.58, p = 0.0038), the overall rate of minor hypoglycaemia remained low with both the BIAsp and the BHI treatments (13.1 vs. 8.3 episodes/patient year respectively). Overall safety and patient satisfaction were similar with the two insulin therapies.

CONCLUSIONS

This trial confirmed that a thrice-daily BIAsp regimen can safely be used to intensify treatment for patients inadequately controlled on twice-daily BHI. A treat-to-target trial is required to explore the full potential of the BIAsp regimens and evaluate their use as a viable alternative to intensification with a basal-bolus regimen.

Lispro insulin-induced lipoatrophy: a new case

Lipoatrophy (LA) is a rare complication of insulin treatment in type 1 diabetes mellitus. The pathogenesis of insulin-induced LA is still unknown. Many theories suggest immunological reactions. We report a 4-yr-old Saudi girl with LA probably induced by lispro insulin. A review of the literature on the clinical features, pathophysiology, differential diagnosis, and treatment is briefly discussed.

Insulin's 85th anniversary--An enduring medical miracle

In 1922, the discovery of insulin led to a revolution in diabetes management. Since then, many improvements have been made to insulin preparations: early preparations of bovine and porcine insulins were purified and their duration of action prolonged, giving rise to the introduction of Neutral Protamine Hagedorn (NPH) insulin and monocomponent insulins. Then, with the advances in genetic engineering in the 1980s, it became possible to produce recombinant human insulin. Nowadays, modern molecular biology techniques enable the production of insulin analogues, which have several advantages over human insulin preparations including a reduced risk of hypoglycaemia. Insulin delivery is still predominantly via subcutaneous injections, but alternative routes of insulin administration are being investigated. Pulmonary delivery has emerged as the most feasible option thus far but oral delivery is an ultimate goal, although basic problems of insulin stability in the gut and absorption from the gastrointestinal tract still need to be resolved. The availability of a true artificial pancreas by means of a closed-loop system, linking continuous glucose monitoring with insulin-pump technology, would also constitute a significant advance, but major technological problems still need to be overcome.

Premixed insulin treatment for type 2 diabetes: analogue or human?

The progressive nature of type 2 diabetes makes insulin initiation a necessary therapeutic step for many patients. Premixed insulin formulations containing both basal and prandial insulin (so called biphasic insulin) are often prescribed because they are superior to long- or intermediate-acting insulin in obtaining good metabolic control. In addition, they are considered as an attractive alternative to classical basal-bolus therapy as fewer daily injections are required. Premixed insulin formulations include conventional (e.g. biphasic human insulin 70/30, or 30/70 in European countries, BHI 30) and newer premixed human analogues (e.g. biphasic insulin aspart 70/30, or 30/70 in Europe, BIAsp 30; insulin lispro mix 75/25-Mix 75/25, or Mix 25/75 in Europe). Like conventional premixed human insulin, premixed insulin analogues contain a fixed proportion of soluble, rapid-acting insulin analogue, with protaminated analogue comprising the remainder. Unlike conventional premixes, analogue premixes have more physiological pharmacokinetic and therapeutically more desirable pharmacodynamic profiles than premixed human insulin. Consequently, postprandial glycaemic control is better with premixed insulin analogues than with premixed human insulin. In nontreat-to-target registration trials, the lowering of haemoglobin A(1c) with premixed insulin analogues was not inferior to that seen with premixed human insulin. Minor hypoglycaemia was similar for premixed analogue and premixed human insulins, while major hypoglycaemia appears to be rare with either formulation. The occurrence of adverse events, other than hypoglycaemia, was also similar between various premix insulins. The premixed insulin analogues, BIAsp 30 and Mix 75/25, like the fast-acting analogues from which they are derived, also allow flexible injection timing, relative to meal timing, thus improving adherence, compliance and quality of life compared with premixed human insulin. Overall, the evidence suggests that premixed insulin analogues are cost effective and have useful advantages over premixed human insulin for the treatment of type 2 diabetes.

Benefits of complementary therapy with insulin aspart versus human regular insulin in persons with type 2 diabetes mellitus

BACKGROUND

Absorption rates of the phosphate-buffered insulin analogs aspart, lispro, and glulisine prevail over that of regular human insulin. The aim of this prospective observational open-label controlled study was to compare the effects of aspart and human regular insulin resulting from their sequential long-lasting routine administration in small preprandial boluses to individuals with type 2 diabetes according to identical algorithms.

METHODS

Fifty-seven individuals with type 2 diabetes 64.0 +/- 1.29 (mean +/- SE) years old with diabetes' duration of 12.4 +/- 1.06 years, treated with human regular insulin for 5.2 +/- 0.44 years, and a serum C-peptide level of 1.1 +/- 0.10 nmol/L were enrolled into the study. Following two checkups performed in the course of the 364 +/- 17.9-day baseline period, human regular insulin was replaced with aspart in equivalent boluses, and two checkups in the course of 330 +/- 11.1-day sequential period were performed. The control group consisted of 17 individuals with type 2 diabetes 68.4 +/- 2.36 years old with diabetes' duration of 9.9 +/- 1.57 years, treated with insulin for 4.2 +/- 0.57 years, and a C-peptide level of 1.1 +/- 0.11 nmol/L. Data were analyzed using the statistical program SPSS version 10.1. (SPSS, Inc., Chicago, IL).

RESULTS

Following the switch from human regular insulin to aspart, hemoglobin A1c (HbA1c) decreased from 8.4 +/- 0.23% at baseline to 7.9 +/- 0.17% (P = 0.031), and thereafter to 7.5 +/- 0.20% (P < 0.001), while plasma glucose concentrations in 10-point profiles, daily insulin dose (37.1 +/- 1.39 IU/day), body mass index (BMI) (30.5 +/- 0.82 kg/m(2)), and frequency of hypo- and hyperglycemic episodes did not change (P > 0.05). Patients quote satisfaction was good. No adverse events were recorded. In the control group, no significant change of baseline HbA1c (8.4 +/- 0.54%), insulin dose (33.1 +/- 3.17 IU/day), and BMI (32.1 +/- 1.12 kg/m(2)) was found.

CONCLUSION

Aspart appears to be more effective than human regular insulin for complementary insulin treatment in individuals with type 2 diabetes.

Health care resource utilization and expenditures associated with the use of insulin glargine

BACKGROUND

Newer insulins, such as long-acting analogues, offer promise of better glycemic control, reduced risk for diabetes complications, and moderation of health care use and costs.

OBJECTIVE

We studied initiation of insulin glargine to evaluate its association with subsequent health service utilization and estimated expenditures.

METHODS

Patients of the Veterans Health Administration, US Department of Veterans Affairs (VA) who initiated insulin glargine (n=5064) in 2001-2002 were compared with patients receiving other insulin (n=69,944), matched on prescription month (index date). Inpatient and outpatient VA care in the 12 months after a patient's index date was evaluated using Tobit regression, controlling for prior utilization, demographic characteristics, comorbidities, glycosylated hemoglobin (HbA(1c)) levels, and diabetes severity. National average utilization costs and medication acquisition costs were used to estimate the value of VA expenditures.

RESULTS

Compared with other insulin users, insulin glargine initiators had higher HbA(1c) values (8.72% vs 8.16%) prior to the index date, but greater subsequent HbA(1c) reduction (-0.50% vs -0.22%). After adjustment for age, prior utilization, HbA(1c) levels, and other factors, insulin glargine initiation was associated with 2.4 (95% CI, 1.1-3.7) fewer inpatient days for patients with any hospital admission (US $820 lower costs per initiator), 1.6 (1.2-1.9) more outpatient encounters ($279 higher costs per initiator), and $374 ($362-$387) higher costs for diabetes medications. The net difference was an average lower VA cost of $166 (-$290 to $622) per patient.

CONCLUSIONS

Insulin glargine use was associated with decreased inpatient days but increased outpatient care, and the value of the net change in utilization to VA offset the additional medication expenditures. Initiation of insulin glargine improves glycemic control and may reduce time in hospital without additional use of health resources.

Glycemic control with insulin glargine as part of an ethnically diverse, community-based diabetes management program

OBJECTIVE

To evaluate the contribution of long-acting basal insulin therapy (insulin glargine) to glycemic control in a predominantly Hispanic population participating in a community-based diabetes management program, Project Dulce.

RESEARCH DESIGN AND METHODS

This retrospective analysis included 3122 adult patients with diabetes from 17 community clinics in San Diego County, California who participated in Project Dulce between July 2000 and March 2003. A subset of 180 patients received insulin glargine because of ongoing, inadequate glycemic control (ie, elevated HbA1c). Glycemic control was evaluated by mean adjusted HbA1c during follow-up clinical visits using hierarchical linear modeling, with values determined separately before and after initiation of insulin glargine.

RESULTS

At baseline, the mean number of individuals with hypoglycemia, presence of diabetic complications, and duration of diabetes were greater in the glargine group that in the reference group. HbA1c at baseline was 8.79 and 9.44 (P = 0.019) in the reference and glargine groups, respectively. Mean adjusted HbA1c in the glargine group was 8.80 at baseline, 7.89 before initiation of insulin glargine (P < 0.001 vs baseline), and 7.34 after adding insulin glargine (P < 0.001 vs pre-glargine). In the reference group, mean adjusted HbA1c decreased from 8.81 at baseline to 7.40 during follow-up (P < 0.001 vs baseline).

CONCLUSIONS

A comprehensive program of diabetes care in Project Dulce improved HbA1c significantly in a predominantly Hispanic population. Adding long-acting basal insulin therapy with insulin glargine produced significant incremental improvement in HbA1c.

Pramlintide in the treatment of diabetes

Diabetes treatment has traditionally focused on correcting insulin deficiency with exogenous insulin and oral agents designed to enhance insulin secretion or insulin sensitivity in peripheral tissues. The more recent view of diabetes as a disease that affects multiple hormones in addition to insulin has led to the development of new therapies more broadly aimed at restoring glucose homeostasis by correcting abnormalities in additional glucoregulatory hormones. Pramlintide, a synthetic analogue of the beta-cell hormone amylin, regulates the appearance of glucose in the circulation following meals through several mechanisms of action: slowing gastric emptying, preventing inappropriate postprandial secretion of glucagon and increasing satiety. Long-term studies have demonstrated that pramlintide improves postprandial glucose fluctuations and A1C while reducing insulin dose and body weight. This combination of benefits associated with pramlintide makes it an attractive new treatment option for patients with diabetes. Clinical Trial Registry Numbers: 137-155 open-label clinical trial: NCT00108004 (Pramlintide long-term, placebo-controlled clinical trials were completed prior to the requirement for NCT registry).

Inhaled insulin delivery--where are we now?

Since 1925, when the concept of treating diabetes with inhaled insulin (INH) was originally published, a number of clinical challenges have been resolved through technological advancements. Efforts by pharmaceutical partnerships or individual companies have resulted in the development of both injection-free devices and novel insulin formulations. Four different INH systems are now in phase 3 of clinical development, and several other INH systems are in earlier stages of clinical study. Clinical data consistently demonstrate that INH therapy is comparable to subcutaneous (SC) therapy in improving glycaemic control in patients with either type 1 or type 2 diabetes, generally without greater risk of overall hypoglycaemia. INH is generally well tolerated and appears to be safe. Adverse-event profiles for INH therapies are similar to SC insulin therapy, with the majority of events being reported as being mild to moderate. Long-term safety studies are ongoing, with emphasis on evaluating the impact of INH therapy on pulmonary function and immune responses. Although small, reversible decreases in pulmonary diffusion capacity (DL(co)) and FEV1 have been reported in response to INH, pulmonary function and structure do not appear to be affected in any clinically significant way. While insulin antibodies are increased in INH therapy, these antibodies have not been correlated with haemoglobin A1c (HbA1c), insulin dosage, hypoglycaemia, pulmonary function or adverse events. Nevertheless, properly controlled, long-term studies will best answer any remaining concerns. From the patient's perspective, INH therapy is preferred by the majority of patients over conventional SC insulin therapy. Studies have shown that patients prefer INH therapy, because it provides greater lifestyle flexibility and social acceptability while at the same time avoiding the pain associated with injection. Thus, after more than 80 years during which the injection route has been the only means of administering insulin, patients and physicians may soon avail themselves of another valuable tool in management of diabetes.

Tissue selectivity of insulin detemir action in vivo

AIMS/HYPOTHESIS

Recombinant DNA technology is a useful tool that can be used to create insulin analogues with modified absorption kinetics to improve glycaemic control in patients with type 1 and type 2 diabetes. Among conventional insulin analogues, which are usually created by amino acid exchange, insulin detemir is the first analogue to be acylated with a fatty acid to enable reversible albumin binding. In this study we determined activation of the insulin receptor (IR)-signalling cascade by insulin detemir at the level of IR and IR substrate (Irs) phosphorylation, as well as downstream signalling elements such as phosphatidylinositol 3-kinase and Akt, and performed epidural EEG in vivo.

METHODS

C57Bl/6 mice were injected i.v. with either insulin detemir or human insulin and Western blot analysis was performed on liver, muscle, hypothalamic and cerebrocortical tissues. Moreover, cerebrocortical activity was detected by EEG in awake mice and cerebral insulin concentrations were measured following human insulin and insulin detemir injection.

RESULTS

The time course and extent of IR phosphorylation in peripheral tissues were similar following insulin detemir treatment compared with human insulin, but insulin signalling in hypothalamic and cerebrocortical tissue determined by tyrosine-phosphorylation of the IR and Irs2 proteins occurred faster and was enhanced due to a higher insulin detemir concentration in the brain. Moreover, epidural EEG in mice displayed increased cortical activity using insulin detemir.

CONCLUSIONS/INTERPRETATION

Taken together, these data suggest that insulin detemir has a tissue-selective action, with a relative preference for brain compared with peripheral tissues.

The Treat-to-Target Trial and related studies

OBJECTIVE

To describe the rationale for, and the findings of, the Treat-to-Target Trial and to compare its results with those of two subsequent studies based on the same concepts.

METHODS

The 24-hour pattern of hyperglycemia in type 2 diabetes is presented, and its separate components are identified in an attempt to help optimize therapeutic interventions for diabetes. In addition, the treat-to-target concept, including glycemic outcomes and potential adverse effects, is discussed.

RESULTS

Using a hemoglobin A1c (A1c) value of 7% as a treatment goal based on evidence from interventional studies and a fasting plasma glucose level of 100 mg/dL as a target for titration of dosage of basal insulin, the Treat-to-Target Trial tested two hypotheses. It confirmed that addition of basal insulin to previously unsuccessful oral therapies can, using a simple algorithm, restore glycemic control to 7% A1c or better in most patients with type 2 diabetes. It also confirmed that a long-acting insulin analogue, glargine, causes less hypoglycemia than human NPH insulin when used in this way. Two subsequent studies using similar treatment algorithms showed comparable ability to improve glycemic control but also demonstrated more frequent unwanted effects of insulin treatment when a different comparator regimen was used to initiate therapy than when a glargine-based regimen was used.

CONCLUSION

Initiation of insulin therapy with structured titration to glycemic targets can frequently, but not always, restore glycemic control in patients with type 2 diabetes when orally administered agents are no longer successful alone. Future trials should include hypoglycemia and weight gain as specific, objectively measured endpoints to assess their importance as adverse effects of titrating insulin dosage to target. Studies are needed to assess ways to control postprandial as well as basal hyperglycemia and thus enable almost all patients with type 2 diabetes to reach A1c targets.

Dose response of inhaled dry-powder insulin and dose equivalence to subcutaneous insulin lispro

OBJECTIVE

To determine the pharmacokinetic (PK) and glucodynamic (GD) dose response of human insulin inhalation powder (HIIP) delivered via AIR particle technology and dose equivalence to subcutaneous (SC) insulin lispro.

RESEARCH DESIGN AND METHODS

Twenty healthy, nonsmoking, male or female subjects (aged 29.6 +/- 6.9 years, BMI 23.2 +/- 2.3 kg/m2, means +/- SD) with normal forced vital capacity and forced expiratory volume were enrolled in an open-label, randomized, seven-period, euglycemic glucose clamp, cross-over trial. Each subject received up to four single doses of HIIP (2.6, 3.6, 5.2, or 7.8 mg) and three doses of SC lispro (6, 12, or 18 units) from 5 to 18 days apart.

RESULTS

HIIP demonstrated a similar rapid onset but an extended time exposure and a prolonged duration of effect (late t(50%) 412 vs. 236 min, P < 0.001) compared with SC lispro. The HIIP versus SC lispro doses of 2.6 mg vs. 6 units, 5.2 mg vs. 12 units, and 7.8 mg vs. 18 units achieved similar PK area under the serum immunoreactive insulin (IRI) concentration-versus-time curve from time zero until the serum IRI concentrations returned to the predose baseline value [AUC(0-t')] and GD (G(tot)) responses. The median insulin (t(max)) was not different between HIIP and SC lispro (45 min for both), although the median time of return to baseline for PK was apparently longer for HIIP compared with SC lispro (480 vs. 360 min). Relative bioavailability and relative biopotency of HIIP were consistent across doses (8 and 9%).

CONCLUSIONS

While the time-action profile was longer for HIIP than for SC lispro, both treatments showed rapid initial absorption and similar overall PK exposure and GD effect. HIIP was as well tolerated as SC lispro, thereby offering a promising alternative to injectable insulin therapy.

Synthesis and Evaluation of Insulin−Human Serum Albumin Conjugates

A series of human insulin maleimido derivatives with short and long linkers was synthesized by exploiting the variations in the pK(a) values and environment of the three amino groups present in the protein. The syntheses were accomplished in organic solvent because of maleimide's instability in basic aqueous media. The derivatives thus obtained were conjugated to the free thiol on Cys34 of human serum albumin (HSA) and purified. A structure-activity relationship based on in vitro receptor binding and activation results for this series of insulin-HSA conjugates showed that the best compounds were attached at the B1 position of insulin with either short or long linkers. Two conjugates were administered subcutaneously to streptozotocin-induced diabetic rats and found to possess blood glucose normalizing activity up to 8 h post-administration. The return to diabetic plasma glucose levels was not observed within the time frame of the experiment (48 h). In comparison, the insulin-treated group's normalization activity lasted 2 h and returned to a diabetic level at 8 h. The onset of the conjugate activities were delayed by 1 h when compared to the activity of human insulin. The study results led to the identification of CJC-1575 as a potent and long lasting human insulin analogue.

PEGylated insulin in PLGA microparticles. In vivo and in vitro analysis

A novel controlled release formulation has been developed with PEGylated human insulin encapsulated in PLGA microspheres that produces multi-day release in vivo. The insulin is specifically PEGylated at the amino terminus of the B chain with a relatively low molecular weight PEG (5000 Da). Insulin with this modification retains full biological activity, but has a limited serum half-life, making encapsulation necessary for sustained release beyond a few hours. PEGylated insulin can be co-dissolved with PLGA in methylene chloride and microspheres made by a single o/w emulsion process. Insulin conformation and biological activity are preserved after PEGylation and PLGA encapsulation. The monolithic microspheres have inherently low burst release, an important safety feature for an extended release injectable insulin product. In PBS at 37 degrees C, formulations with a drug content of approximately 14% show very low (< 1%) initial release of insulin over one day and near zero order drug release after a lag of 3-4 days. In animal studies, PEG-insulin microspheres administered subcutaneously as a single injection produced < 1% release of insulin in the first day but then lowered the serum glucose levels of diabetic rats to values < 200 mg/dL for approximately 9 days. When doses were given at 7-day intervals, steady state drug levels were achieved after only 2 doses. PEG-insulin PLGA microparticles show promise as a once-weekly dosed, sustained release basal insulin formulation.

Making the transition from oral to insulin therapy

The typically long delay in starting insulin for patients with type 2 diabetes mellitus may be due in part to uncertainty about how best to make the transition from oral therapy to insulin. Recent studies show that when appropriate glycemic targets are sought, with systematic titration of insulin dosage, several methods of beginning insulin may be successful. Notably, either starting with a single injection of basal insulin or starting with 3 injections of short-acting insulin at mealtimes can be effective. Studies also suggest that continuing oral therapies and using insulin analogues rather than human insulins may improve the effectiveness of insulin treatment relative to the rate of hypoglycemia and gain of weight typically seen in this setting. Starting with a single injection of insulin to control basal glycemia while continuing oral therapy is the simplest approach, and lends itself to stepwise addition of mealtime injections as needed to bring most patients to glycemic targets in a logical and practical way. Future studies should consider not only the ability of regimens to reach hemoglobin A(1c) targets but also the burden of adverse effects accompanying this effort with a given method.

Insulin glulisine: insulin receptor signaling characteristics in vivo

In recent years, recombinant DNA technology has been used to design insulin molecules that overcome the limitations of regular insulin in mealtime supplementation. However, safety issues have been raised with these alternatives, as the alteration of the three-dimensional structure may alter the interaction with the insulin and/or IGF-I receptors and therefore lead to the activation of alternate metabolic as well as mitogenic signaling pathways. It is therefore essential to carefully study acute and long-term effects in a preclinical state, as insulin therapy is meant to be a lifelong treatment. In this study, we determined in vivo the insulin receptor signaling characteristics activated by insulin glulisine (Lys(B3), Glu(B29)) at the level of insulin receptor phosphorylation, insulin receptor substrate phosphorylation, and downstream signaling elements such as phosphatidylinositol (PI) 3-kinase, AKT, and mitogen-activated protein kinase. C57BL/6 mice were injected with insulin glulisine or regular insulin and Western blot analysis was performed for liver and muscle tissue. The extent and time course of insulin receptor phosphorylation and activation of downstream signaling elements after insulin glulisine treatment was similar to that of human regular insulin in vivo. Moreover, insulin signaling in hypothalamic tissue determined by PI 3-kinase activity was comparable. Therefore, insulin glulisine may be a useful tool for diabetes treatment.

A Critical Appraisal of the Role of Insulin Analogues in the Management of Diabetes Mellitus

Insulin is one of the oldest and best studied treatments for diabetes mellitus. Despite many improvements in the management of diabetes, the nonphysiological time-action profiles of conventional insulins remain a significant obstacle. However, the advent of recombinant DNA technology made it possible to overcome these limitations in the time-action profiles of conventional insulins. Used as prandial (e.g. insulin lispro or insulin aspart) and basal (e.g. insulin glargine) insulin, the analogues simulate physiological insulin profiles more closely than the older conventional insulins. If rapid-acting insulin analogues are used in the hospital, healthcare providers will need a new mind-set. Any error in coordination between timing of rapid-acting insulin administration and meal ingestion may result in hypoglycaemia. However, guidelines regarding in-hospital use of insulin analogues are few. The safety profile of insulin analogues is still not completely established in long-term clinical studies. Several studies have shown conflicting results with respect to the tumourigenic potential of this new class of agents. The clinical implications of these findings are not clear. Although novel insulin analogues are promising 'designer drugs' in our armamentarium to overcome some of the limitations of conventional insulin therapy, cost may be a limiting factor for some patients.

Comparison of pharmacokinetic and pharmacodynamic properties of single-dose oral insulin spray and subcutaneous insulin injection in healthy subjects using the euglycemic clamp technique

BACKGROUND

Oral insulin spray is a new, noninjectable method of insulin delivery. This system delivers an aerosol of uniform-sized droplets containing regular human insulin at a high velocity into the oropharyngeal cavity for local transmucosal absorption.

OBJECTIVE

The purpose of this study was to compare the pharmacokinetic and pharmacodynamic properties of single-dose oral insulin spray and SC insulin injection in healthy subjects.

METHODS

Healthy male volunteers aged 21 to 25 years participated in this open-label study conducted at the Diabetes Unit, Hadassah-Hebrew University Hospital, Jerusalem, Israel. Subjects presented at 2 visits separated by 7 to 14 days. At both visits, the euglycemic clamp technique was used to maintain a constant blood glucose level. At one visit, subjects received regular human insulin 0.1 U/kg by SC injection. At the other visit, subjects received 15 puffs (150 U) of oral insulin spray. The pharmacokinetic (insulin absorption) and pharmacodynamic (glucose uptake) properties of the drugs were evaluated using blood analyses over the subsequent 360 minutes.

RESULTS

Six volunteers were enrolled (mean [SD] age, 22.8 [1.2] years; mean [SD] body mass index, 23.2 [2.2] kg/m(2)). The mean (SD) baseline-corrected C(max) was significantly higher with oral insulin spray compared with SC insulin (54.0 [20.3] vs 30.8 [6.1] microU/mL; P = 0.028). Mean (SD) T(max) was significantly shorter with oral insulin spray compared with SC insulin (23.3 [5.2] vs 83.3 [42.2] minutes; P = 0.027). The mean (SD) time to maximal metabolic effect (maximum glucose infusion rate [GIR(max)]) (44.2 [8.6] vs 100.0 [35.6] minutes) and late time to half-maximal effect (101.0 [41.0] vs 257.2 [27.8] minutes) were shorter with oral insulin spray compared with SC insulin (both, P = 0.028). The baseline-corrected GIR(max) (6.8 [3.3] vs 6.2 [2.3] mg/kg . min) and glucose consumption (396.7 [178.0] vs 432.1 [226.0] mg/kg) during the 120 minutes after study drug administration were comparable between oral and SC insulin, respectively.

CONCLUSIONS

In this study in a small, selected population of healthy male subjects under euglycemic conditions, oral insulin spray was associated with a higher C(max), shorter T(max), and faster time to peak glucose uptake compared with SC insulin. The short T(max) and the 120-minute duration of effect of oral insulin spray suggest it may be a promising alternative for fulfilling meal-related insulin requirements in persons with diabetes.

Intentional Overdose with Insulin Glargine and Insulin Aspart

Reports of intentional massive overdoses of insulin are infrequent. A review of the literature revealed no reports of overdose attempts with either insulin glargine or insulin aspart. We report the case of a 33-year-old woman without diabetes mellitus who intentionally injected herself with an overdose of both products, which belonged to her husband. She arrived at the emergency department 15 hours after her suicide attempt, which took place the night before. Her husband had checked her blood glucose level throughout the night and had given her high-carbohydrate drinks and foods. The patient had a history of obsessive-compulsive disorder, major depression, and numerous suicide attempts. She recovered from the resulting hypoglycemia after 40 hours of dextrose infusion and was transferred to a mental health facility. The main danger associated with insulin overdose is the resultant hypoglycemia and its effects on the central nervous system; hypokalemia, hypophosphatemia, and hypomagnesemia also can develop with excess insulin administration. Dextrose infusion, with liberal oral intake when possible, and monitoring for electrolyte changes, making adjustments as needed, are recommended for the treatment of intentional insulin overdose.

Nocturnal hypoglycemia in patients with insulin-treated diabetes

While use of intensive insulin therapy has proven effective for reducing risk of long-term complications of hyperglycemia in people with diabetes, overnight hypoglycemia remains a significant barrier to intensive therapy. Findings from numerous studies indicate that nocturnal hypoglycemia is a frequent event among patients with type 1 diabetes, while severe hypoglycemic episodes are approximately three times more likely in patients on intensive insulin therapy than in those on conventional therapy. Nocturnal hypoglycemia remains frequent, even when specific approaches-use of short-acting insulin analogues to manage postprandial glucose surges, peakless long-acting insulin analogues as basal therapy, and strategically selected bedtime snacks-aim to avert this problem. Thus, nocturnal hypoglycemia continues to threaten the well-being of patients with diabetes and cause concerns for their family members and caregivers. Continuing research is required to improve methods for detection and prompt correction of hypoglycemia in order to achieve a safe level of euglycemia in people with diabetes.

Lispro is superior to regular insulin in transient intensive insulin therapy in type 2 diabetes

OBJECTIVE

The optimal approach to relatively recent onset type 2 diabetes patients is still unknown. We speculated that the use of short-acting insulin analogs might be of particular benefit in this context.

PATIENTS AND METHODS

To explore this possibility, we compared the effect on beta- and alpha-cell function of transient intensive insulin therapy using lispro versus human regular insulin in a total of 21 type 2 diabetic patients who were randomly assigned to 14-days intensive insulin therapy consisting of bedtime NPH insulin plus three injections of mealtime lispro (n=11) or regular insulin (n=10). The dosages of both types of insulin were adjusted to attain preprandial glucose levels of <6.1 mmol/l within 1 week with similar rates of glucose decline. An oral glucose tolerance test (OGTT) was performed at day 0 (baseline), 7, and 14; plasma glucose, serum insulin, and plasma glucagon responses over 0-120 minutes were measured, and calculated as the area under the curve (AUC).

RESULTS

Lispro led to a significant reduction in glucose-AUC and also an increase in insulin-AUC versus regular insulin on day 7. Glucagon secretion following OGTT was well suppressed with lispro on day 14 compared to regular insulin.

CONCLUSION

Two-week intensive insulin therapy with lispro appeared to be more effective than that with regular insulin in type 2 diabetes in attaining both more rapid beta-cell rest and greater suppression of glucagon. These changes may provide significant long-term benefits.

Reduction of cardiovascular morbidity and mortality in type 2 diabetes. A rational approach to hypoglycemic therapy

Type 2 diabetes mellitus is the single most important risk factor for the development of coronary artery disease. Unfortunately, the traditional therapeutic strategies for the treatment of hyperglycemia have proven to be ineffective in preventing cardiovascular complications. In recent years the number of available hypoglycemic agents has increased and considerable progress has been made regarding the comprehension of the pathophysiology of diabetes and its vascular complications. In the present article we firstly present benefits and risks of intensive vs standard hypoglycemic intervention, and the pros and cons of therapy targeted to postprandial hyperglycemia. Secondly, we discuss the cardiovascular effects of sulfonylurea agents and insulin, focusing on the role of intensive insulin treatment in the context of acute coronary syndromes. Thirdly, we review the epidemiological, clinical and experimental evidence linking insulin resistance and cardiovascular disease. Finally, we present the rationale and the role of metformin and thiazolidinedionetherapy in the prevention of cardiovascular complications. We conclude that the optimal use of the full spectrum of hypoglycemic agents has the potential to play a key role in the prevention of diabetes-related macrovascular complications.

Ethical use of long-acting medications in the treatment of severe and persistent mental illnesses

volunteerism Mental illnesses are prevalent, cause great suffering, and are burdensome to society. Traditional "depot" antipsychotic agents are used to treat the most severely and persistently mentally ill individuals. They will soon be joined by new atypical antipsychotic medications in long-acting formulations. These long-acting medications pose special ethical issues, but may greatly benefit some people who suffer from severe and persistent mental illnesses. The objective of the current report is to highlight ethical considerations related to the use of long-acting antipsychotic medications. An analysis centering on the ethical concepts of voluntarism, beneficence, and justice is performed, integrating relevant empirical evidence and bioethics principles. Two main conceptual issues related to constraints upon voluntarism and coercion exist. Careful examination of ethically important empirical evidence suggests that voluntarism may not be perceived as an issue for some persons receiving depot antipsychotic medications. A favorable balance of benefits and risks has been documented for some individuals with severe and persistent mental illnesses. Access to care, innovative treatments, and long-acting antipsychotic medications may arise as an issue of justice and nondiscrimination in the care of mental illness. Considerations of justice indicate that long-acting medications may need to be used more frequently and earlier in the course of severe and persistent mental illness for select patients. We conclude that great care should be given to ethically important issues surrounding voluntarism, beneficent care, and equitable access to innovative psychiatric treatments, especially for persons who carry the burden of stigma as well as severe and persistent mental illness.

Inhaled insulin in diabetes mellitus

BACKGROUND

Insulin therapy often relies on multiple daily injections of insulin. However this is a considerable burden to many people with diabetes and adherence to such an insulin regimen can be difficult to maintain, hence compromising optimal glycaemic control. Also, short acting injected insulin is absorbed more slowly than insulin released by the normal pancreas in response to a meal. Inhaled insulin has the potential to reduce the number of injections to perhaps one long-acting insulin per day, and provide a closer match to the natural state, by more rapid absorption from the lung.

OBJECTIVES

To compare the efficacy, adverse effects and patient acceptability of inhaled versus injected insulin.

SEARCH STRATEGY

A sensitive search strategy for randomised controlled or cross-over trials was combined with key terms for inhaled insulins. Databases searched were: The Cochrane Library, MEDLINE, PubMed, EMBASE, Science Citation Index, BIOSIS, Web of Science Proceedings, National Research Register UK, Current Controlled Trials, ClinicalTrials.gov, Conference Papers Index, LexisNexis, and web sites of the ADA and EASD were searched for recent meeting abstracts. Reference lists and journals were handsearched. There were no language restrictions on searching. Manufacturers of inhaled insulin were also contacted. Date of last search October 2002.

SELECTION CRITERIA

Only randomised controlled trials with parallel groups or controlled cross-over trials, including type 1 or type 2 diabetic patients of any age treated with insulin, were considered eligible. The minimum trial duration considered was 10 weeks, as this is the time taken for glycated haemoglobin to reliably reflect changes in glycaemic control.

DATA COLLECTION AND ANALYSIS

Trial selection and evaluation of study quality was performed independently by two reviewers. The quality of reporting of each trial was assessed according to a modification of the criteria outlined in Centre for Reviews and Dissemination (CRD) Report 4, Spitzer; and Jadad.

MAIN RESULTS

Six randomised controlled trials were found and the overall number of participants was 1191. Three trials included patients with type 1 diabetes and three with type 2 diabetes. Three trials had a duration of 24 weeks, and three of 12 weeks. All were open label. There was insufficient information to determine the study quality. Results for HbA1c were similar for all trials, in that all showed comparable glycaemic control for inhaled insulin compared to an entirely subcutaneous regimen. All trials that reported patient satisfaction and quality of life showed that these were significantly greater in the inhaled insulin group. Overall there was no difference in total hypoglycaemic episodes between the groups, but one trial showed a statistically significant increase in severe hypoglycaemic episodes for the inhaled insulin group. No adverse pulmonary effects were observed in any of the studies, but longer follow-up will be required to be sure that there are no adverse side-effects. Cavets include: few studies published in full (so quality could not be assessed), and only two studies used the same basal regimen in both the inhaled and injected groups.

REVIEWERS' CONCLUSIONS

Inhaled insulin taken before meals, in conjunction with an injected basal insulin, has been shown to maintain glycaemic control comparable to that of patients taking multiple daily injections. The key benefit appears to be that patient satisfaction and quality of life are significantly improved, presumably due to the reduced number of daily injections required. However, the patient satisfaction data is based on five trials, of which only two have been published in full; also the three trials containing quality of life data are all only published in abstract form at present. In addition, longer term pulmonary safety data are still needed. Also, the lower bioavailability, and hence higher doses of inhaled insulin required, may make it less cost-effective than injected insulin.

Insulin Aspart

Insulin aspart (NovoRapid, NovoLog) is a short-acting insulin analogue, which has a faster onset and shorter duration of action than regular human insulin. Insulin aspart administered immediately before meals provided significantly greater improvements in glycosylated haemoglobin and better postprandial glycaemic control than regular human insulin administered 30 minutes before meals, when used in a basal-bolus regimen with neutral protamine Hagedorn (NPH) insulin, in randomised, nonblind studies in patients with type 1 diabetes mellitus. In patients with type 2 diabetes, insulin aspart provided similar glycaemic control to regular human insulin, administered in a basal-bolus regimen with NPH insulin. Small studies suggest that the use of insulin aspart in combination with oral hypoglycaemic agents may be beneficial. Insulin aspart, administered by continuous subcutaneous insulin infusion (CSII) provided better glycaemic control than insulin aspart multiple daily injection regimens in patients with type 1 (but not type 2) diabetes, and had similar efficacy to CSII with insulin lispro or regular human insulin in type 1 diabetes. Limited studies show insulin aspart to be effective in children, adolescents and young adults with type 1 diabetes. Insulin aspart had a tolerability profile similar to that of regular human insulin in clinical trials. The incidence of major or nocturnal hypoglycaemic events reported in patients receiving insulin aspart was lower than that of regular human insulin in several studies. In conclusion, insulin aspart, administered immediately before meals in a basal-bolus regimen with NPH insulin, provided better long-term glycaemic control than regular human insulin administered 30 minutes before meals in patients with type 1 diabetes, and was as effective as regular human insulin in patients with type 2 diabetes. A significantly lower risk of hypoglycaemia was seen in several trials. Insulin aspart CSII provided better glycaemic control than insulin aspart multiple daily subcutaneous injection (MDI) in patients with type 1 (but not type 2) diabetes and had similar efficacy to CSII with insulin lispro or regular human insulin in type 1 diabetes. Insulin aspart is an effective and well tolerated alternative to regular human insulin and insulin lispro for the maintenance of glycaemic control in patients with type 1 or 2 diabetes.

Insulin therapy for type 2 diabetes

Type 2 diabetes is a disease of insulin deficiency along with insulin resistance, and the natural history is a progressive worsening of insulin secretion over time. The obvious conclusion supported by clinical experience is most patients will eventually need insulin therapy. However, there is often a reluctance on the part of many care providers to prescribe insulin because of fears of weight gain, hypoglycemia, or cardiovascular consequences, or because the patient is unwilling. Another problem is many practitioners are uncertain how to use insulin in type 2 diabetes. This review discusses the benefits of insulin therapy in patients with type 2 diabetes when it is required for optimal glycemia control. It also debunks the fears over unwanted consequences such as severe hypoglycemia and worsening of atherosclerotic cardiovascular disease. Finally, it provides a "hands on" approach on how to start basal insulin therapy and multishot insulin therapy in type 2 diabetes.