Euglycemic ketosis in patients with type 2 diabetes on SGLT2-inhibitor therapy-an emerging problem and solutions offered by diabetes technology.

Diabetic ketoacidosis is an infrequent but life-threatening acute complication of diabetes, affecting predominantly patients with type 1 diabetes, children, and pregnant women, where ketosis is usually associated with marked hyperglycemia. Recently, an increasing number of cases have been reported of euglycemic diabetic ketoacidosis in patients with type 2 diabetes receiving sodium-glucose cotransporter 2 inhibitor treatment in routine practice. There is a minor, but not negligible diabetic ketoacidosis risk associated with this drug class, which was not seen in randomized clinical trials. However, sodium-glucose cotransporter2 inhibitors increase the risk of ketosis by increasing glucagon secretion in the pancreas and decreasing the renal excretion of 3-hydroxybutyrate and acetoacetate. When used in addition to insulin, any insulin dose reduction required to avoid hypoglycemia may lead to insufficient suppression of lipolysis and ketogenesis. sodium-glucose cotransporter2 inhibitor-induced loss of urinary glucose encourages euglycemia. Normo-glycemic or near-normoglycemic diabetic ketoacidosis represents a major threat to the health and well-being of a patient, because it may occur undetected and without any indicative hyperglycemia. In consequence, patients on sodium-glucose cotransporter2 inhibitors are recommended to perform regular blood ketone tests since they are not alerted to incipient diabetic ketoacidosis by glucose testing alone. This option is offered by several blood glucose meters that can also measure ketones with a separate ketone strip or in one case by an automatic parallel ketone assessment from the same strip. The need for extra testing and the associated costs may be a barrier to patient acceptance of this risk mitigation procedure. However, patients who are at risk for euglycemic diabetic ketoacidosis when being treated with sodium-glucose cotransporter2 inhibitors should be specially advised to monitor blood ketone levels on a regular basis.

HbA1c and Age in Non-Diabetic Subjects: An Ignored Association?

Objective: Target HbA1c values given in the most National Therapeutic Guidelines for patients with diabetes and cut-off HbA1c values for diabetes diagnosis are usually not taking the age of the respective patients into account; despite the fact that an increase in HbA1c in subjects without diabetes with age is known for some time. In order to further quantify the association between age and HbA1c in non-diabetic subjects an analysis of one German register was performed. Methods: In this cross-sectional study we analyzed data from 7 699 visits of 2 921 patients without diabetes (age 46.6 y [range 18-93 y]; 69.1% women; BMI 27.6±6.4 kg/m²) who had at least one HbA1c and blood glucose measurement. Data were drawn from an electronic patient record system (EMIL™) in which data were collected between 01/1992 and 01/2014. The patients were divided in 6 age groups (< 30 years [n=1 057];>30-40 years [n=1 160];>40-50 years [n=1 693];>50-60 years [n=1 523];>60-70 years [n=1 310];>70 years [n=956]) and the HbA1c values of these groups were compared. Patients with: gestational diabetes, use of systemic glucocorticoids, malignant neoplasm, age<18 y at time of first visit and IGT were excluded. HbA1c measurements were DCCT adjusted. Results: Patients with age>70 years have a 0.47% [5.14 mmol/mol] higher HbA1c compared to those<30 years. The mean HbA1c of the age groups was:<30 4.98% [30.96 mmol/mol],>30-40 5.07% [31.99 mmol/mol],>40-50 5.17% [33.10 mmol/mol],>50-60 5.33% [34.79 mmol/mol],>60-70 5.42% [35.79 mmol/mol] and>70 years 5.45% [36.10 mmol/mol]. In a multiple linear model the regression coefficient for each year of age increase was ß=0.0074 (p<0.001); thus age results in an increase of 0.074% in HbA1c per decade. Conclusion: HbA1c increases significantly with ageing in people without diabetes. The use of different cut-off values for every age range for diagnosis of diabetes should be discussed.

Home Use of an Artificial Beta Cell in Type 1 Diabetes.

BACKGROUND: The feasibility, safety, and efficacy of prolonged use of an artificial beta cell (closed-loop insulin-delivery system) in the home setting have not been established. METHODS: In two multicenter, crossover, randomized, controlled studies conducted under free-living home conditions, we compared closed-loop insulin delivery with sensor-augmented pump therapy in 58 patients with type 1 diabetes. The closed-loop system was used day and night by 33 adults and overnight by 25 children and adolescents. Participants used the closed-loop system for a 12-week period and sensor-augmented pump therapy (control) for a similar period. The primary end point was the proportion of time that the glucose level was between 70 mg and 180 mg per deciliter for adults and between 70 mg and 145 mg per deciliter for children and adolescents. RESULTS: Among adults, the proportion of time that the glucose level was in the target range was 11.0 percentage points (95% confidence interval [CI], 8.1 to 13.8) greater with the use of the closed-loop system day and night than with control therapy (P<0.001). The mean glucose level was lower during the closed-loop phase than during the control phase (difference, -11 mg per deciliter; 95% CI, -17 to -6; P<0.001), as were the area under the curve for the period when the glucose level was less than 63 mg per deciliter (39% lower; 95% CI, 24 to 51; P<0.001) and the mean glycated hemoglobin level (difference, -0.3%; 95% CI, -0.5 to -0.1; P=0.002). Among children and adolescents, the proportion of time with the nighttime glucose level in the target range was higher during the closed-loop phase than during the control phase (by 24.7 percentage points; 95% CI, 20.6 to 28.7; P<0.001), and the mean nighttime glucose level was lower (difference, -29 mg per deciliter; 95% CI, -39 to -20; P<0.001). The area under the curve for the period in which the day-and-night glucose levels were less than 63 mg per deciliter was lower by 42% (95% CI, 4 to 65; P=0.03). Three severe hypoglycemic episodes occurred during the closed-loop phase when the closed-loop system was not in use. CONCLUSIONS: Among patients with type 1 diabetes, 12-week use of a closed-loop system, as compared with sensor-augmented pump therapy, improved glucose control, reduced hypoglycemia, and, in adults, resulted in a lower glycated hemoglobin level. (Funded by the JDRF and others; AP@home04 and APCam08 ClinicalTrials.gov numbers, NCT01961622 and NCT01778348.).

Biosimilar insulins: guidance for data interpretation by clinicians and users.

Biosimilar insulins are approved copies of insulins outside patent protection. Advantages may include greater market competition and potential cost reduction, but clinicians and users lack a clear perspective on 'biosimilarity' for insulins. The manufacturing processes for biosimilar insulins are manufacturer-specific and, although these are reviewed by regulators there are few public data available to allow independent assessment or review of issues such as intrinsic quality or batch-to-batch variation. Preclinical measures used to assess biosimilarity, such as tissue and cellular studies of metabolic activity, physico-chemical stability and animal studies of pharmacodynamics, pharmacokinetics and immunogenicity may be insufficiently sensitive to differences, and are often not formally published. Pharmacokinetic and pharmacodynamic studies (glucose clamps) with humans, although core assessments, have problems of precision which are relevant for accurate insulin dosing. Studies that assess clinical efficacy and safety and device compatibility are limited by current outcome measures, such as glycated haemoblobin levels and hypoglycaemia, which are insensitive to differences between insulins. To address these issues, we suggest that all comparative data are put in the public domain, and that systematic clinical studies are performed to address batch-to-batch variability, delivery devices, interchangeability in practice and long-term efficacy and safety. Despite these challenges biosimilar insulins are a welcome addition to diabetes therapy and, with a transparent approach, should provide useful benefit to insulin users.

Biosimilar insulins: a European perspective.

Biosimilar insulins are likely to enter clinical practice in Europe in the near future. It is important that clinicians are familiar with and understand the concept of biosimilarity and how a biosimilar drug may differ from its reference product. The present article provides an overview of biosimilars, the European regulatory requirements for biosimilars and safety issues. It also summarizes the current biosimilars approved in Europe and the key clinical issues associated with the use of biosimilar insulins.

Evidence for continuous glucose monitoring: sufficient for reimbursement?

Evidence for continuous glucose monitoring is mounting. Meta-analyses consistently show lowering of HbA1c , and the first trial reporting a reduction in severe hypoglycaemic events in patients with hypoglycaemia unawareness has recently been presented. The more recent trials studied larger numbers of patients and may have shown better results because of improved technology. The various combinations of pump and sensor, with automated bolus calculators and low glucose suspend features, make evaluation more challenging from a reimbursement point of view, but evidence seems convincing enough to justify reimbursement for selected patient groups, including those who have shown a substantial improvement in HbA1c during a trial period, and those with hypoglycaemia unawareness who encountered severe hypoglycaemia in the recent past. More data on cost-efficacy are needed.

Continuous glucose monitoring: quality of hypoglycaemia detection.

AIMS: To evaluate the accuracy of a (widely used) continuous glucose monitoring (CGM)-system and its ability to detect hypoglycaemic events. METHODS: A total of 18 patients with type 1 diabetes mellitus used continuous glucose monitoring (Guardian REAL-Time CGMS) during two 9-day in-house periods. A hypoglycaemic threshold alarm alerted patients to sensor readings <70 mg/dl. Continuous glucose monitoring sensor readings were compared to laboratory reference measurements taken every 4 h and in case of a hypoglycaemic alarm. RESULTS: A total of 2317 paired data points were evaluated. Overall, the mean absolute relative difference (MARD) was 16.7%. The percentage of data points in the clinically accurate or acceptable Clarke Error Grid zones A + B was 94.6%. In the hypoglycaemic range, accuracy worsened (MARD 38.8%) leading to a failure to detect more than half of the true hypoglycaemic events (sensitivity 37.5%). Furthermore, more than half of the alarms that warn patients for hypoglycaemia were false (false alert rate 53.3%). Above the low alert threshold, the sensor confirmed 2077 of 2182 reference values (specificity 95.2%). CONCLUSIONS: Patients using continuous glucose monitoring should be aware of its limitation to accurately detect hypoglycaemia.

Insulin aspart has a shorter duration of action than human insulin over a wide dose-range.

AIMS: Regular human insulin (RHI) at high doses shows prolongation of its duration of action potentially leading to late postprandial hypoglycaemia. This study compared late metabolic activity (4-12 and 6-12 h post-dosing) and duration of action (time to reach late half-maximal activity) over a range of doses between insulin aspart (IAsp) and RHI. METHODS: Pharmacokinetic and pharmacodynamic properties of subcutaneous IAsp and RHI (6, 12 and 24 (I)U) were compared in 16 healthy subjects in this double-blind, randomized, six-way crossover glucose clamp study. RESULTS: With increasing doses of both insulins, metabolic activity, insulin exposure, maximum metabolic effect and maximum serum insulin concentration increased linearly. Late metabolic activity was lower for IAsp than RHI at all doses, reaching statistical significance (p < 0.05) for 12 and 24 (I)U. Likewise, IAsp had a shorter duration of action at all doses (p < 0.01) and reached time to 80% of total metabolic activity earlier at doses of 12 and 24 (I)U (p < 0.05). IAsp, compared with RHI, showed a higher maximum metabolic effect at 12 and 24 (I)U (p < 0.0001) and a stronger early metabolic activity for all three doses (p < 0.05). CONCLUSIONS: IAsp showed a shorter duration of action and, particularly with doses of 12 and 24 (I)U, less late metabolic activity than RHI. These properties might contribute to the lower incidence of hypoglycaemia observed with IAsp versus RHI in clinical trials as lower late metabolic activity should decrease the risk of late postprandial hypoglycaemia.

U-100, pH-Neutral formulation of VIAject(®) : faster onset of action than insulin lispro in patients with type 1 diabetes.

AIMS: VIAject® is a formulation of human insulin with a very fast onset of action. Previous studies used VIAject in a concentration of 25 U/ml and a pH of 4 [VIAject 25 (VJ25)]. Objective of this double blind, three-way crossover study was to compare the pharmacodynamic/pharmacokinetic properties of a novel formulation of VIAject with a concentration of 100 U/ml and a neutral pH [VIAject 7 (VJ7)] with VJ25 and insulin lispro (LIS). METHODS: Forty-three patients with type 1 diabetes [aged 43 (21-65) years, BMI 24.1 (20-28) kg/m(2) and HbA1c 7.5 (5.7-9.5) %] participated in this study. They received subcutaneous injections of 12 U of each insulin formulation under euglycaemic glucose clamp conditions. RESULTS: VJ7 was bioequivalent to VJ25 [90% confidence interval (CI) of the ratios for total insulin AUCs and maximum insulin concentration (C(INS max) ) was within 0.80-1.25]. VJ7 showed a faster absorption compared to LIS [time to C(INS max) 23 vs. 60 min; difference (CI) -30 (-35 to -23)] and faster onset of action [time to early half-maximal glucose infusion rate (GIR) 25 vs. 44 min; -18 (-26 to -10)], and a higher AUC of glucose infusion rate (AUC(GIR) ) in the first 60 min after injection [176 vs. 107 mg/kg; ratio 1.65 (1.27 to 2.14)], contributing to a slightly higher value for AUC(GIR 0-480) [1263 vs. 1095 mg/kg; 1.15 (1.06 to 1.26)]. Maximum GIR was similar between VJ7 and LIS [6.1 vs.6.6 mg/kg/min; ratio 0.93 (0.86 to 1.01)], whereas the duration of action (t(GIR50%-late) ) was longer with VJ7 [274 vs. 228 min; 50 (25 to 73)]. CONCLUSIONS: This formulation of VIAject is bioequivalent to the previously used formulation and has a faster absorption/onset of action than LIS.

Oral glucose tolerance test and HbA1c for diagnosis of diabetes in patients undergoing coronary angiography: [corrected] the Silent Diabetes Study.

AIMS/HYPOTHESIS: The primary aim of this study was to compare the results of HbA(1c) measurements with those of an OGTT for early diagnosis of 'silent diabetes' in patients with coronary artery disease (CAD) undergoing angiography without prediagnosed diabetes. A secondary aim was to investigate the correlation between the extent of CAD and the glycaemic status of the patient. METHODS: Data from 1,015 patients admitted for acute (n = 149) or elective (n = 866) coronary angiography were analysed. Patients with known diabetes were excluded from the study. Using the OGTT results, patients were classified as having normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes. According to the results of the HbA(1c) measurements, patients were classified into three groups: normal (HbA(1c) <5.7% [<39 mmol/mol]), borderline (HbA(1c) 5.7-6.4% [39-47 mmol/mol]) and diabetes (HbA(1c) ≥6.5% [≥48 mmol/mol]). RESULTS: Based on the OGTT, 513 patients (51%) were classified with NGT, 10 (1%) with IFG, 349 (34%) with IGT and 149 (14%) were diagnosed with diabetes. According to HbA(1c) measurements, 588 patients (58%) were classified as normal, 385 (38%) as borderline and 42 (4%) were diagnosed with diabetes. The proportion of patients with IGT and diabetes increased with the extent of CAD (IGT ρ = 0.14, p < 0.001, diabetes ρ = 0.09, p = 0.01). No differences in HbA(1c) were seen among the groups with different extents of CAD (p = 0.652). CONCLUSIONS/INTERPRETATION: An OGTT should be performed routinely for diagnosis of diabetes in patients with CAD undergoing coronary angiography, since HbA(1c) measurement alone appears to miss a substantial proportion of patients with silent diabetes. A limitation of the study is that the OGTT was not performed before the angiography.

Short-term metabolic effects of prednisone administration in healthy subjects.

AIMS: Supraphysiologic glucocorticoid activity is well established to cause impaired glucose tolerance and insulin resistance, yet no study has evaluated dose-dependent effects of low-dose prednisone during short-term oral administration. METHODS: The objective of this study was to quantify the effects of daily 10 or 25 mg prednisone administration for one week on insulin sensitivity by employing a two-step hyperinsulinemic euglycemic glucose clamp (Step 1: insulin infusion = 20 mU/m²/min; Step 2: insulin infusion = 80 mU/m²/min) in healthy, lean males. The amount of glucose infused at steady-state to maintain stable blood glucose [90 mg/dl (4.95 mmol/l)] was used to calculate several indices of insulin sensitivity. RESULTS: During Step 1 of the clamp, whole body glucose disposal (M) was reduced by 35% (p = 0.003) and M/I was reduced by 29% (p = 0.025) for 25 mg prednisone compared to placebo. No appreciable effect of 10 mg prednisone was observed. During Step 2, M was reduced by 33% (p = 0.001) and 15% (p = 0.006) for 25 and 10 mg prednisone compared to placebo; and M/I ratio was reduced by 31% (p < 0.001) and 13% (p = 0.026), respectively. The insulin sensitivity index, Si, calculated as the quotient of augmentation of M/I between Step 1 and 2, was reduced by 35.3% (p < 0.01) and 23.5% (p < 0.05) for 25 and 10 mg prednisone, respectively. CONCLUSION: Administration of relatively low pharmacological doses of prednisone for one week impaired insulin sensitivity in a dose-dependent manner in healthy males. These observed changes in insulin sensitivity are likely to be clinically relevant, especially in individuals predisposed to develop glucose intolerance.

Dynamics of blood electrolytes in repeated hyper- and/or hypoglycaemic events in patients with type 1 diabetes.

AIMS/HYPOTHESIS: Electrolyte disturbances are well-known consequences of the diabetic pathology. However, less is known about the cumulative effects of repeated changes in glycaemia, a characteristic of diabetes, on the electrolyte balance. We therefore investigated the ionic profiles of patients with type 1 diabetes during consecutive hyper- and/or hypoglycaemic events using the glucose clamp. METHODS: In protocol 1, two successive hyperglycaemic excursions to 18 mmol/l were induced; in protocol 2, a hypoglycaemic excursion (2.5 mmol/l) was followed by a hyperglycaemic excursion (12 mmol/l) and another hypoglycaemic episode (3.0 mmol/l). RESULTS: Blood osmolarity increased during hyperglycaemia and was unaffected by hypoglycaemia. Hyperglycaemia induced decreases in plasma Na(+) Cl(-) and Ca(2+) concentrations and increases in K(+) concentrations. These changes were faithfully reproduced during a second hyperglycaemia. Hypoglycaemia provoked rapid and rapidly reversible increases in Na(+), Cl(-) and Ca(2+). In sharp contrast, K(+) levels displayed a rapid and substantial fall from which they did not fully recover even 2 h after the re-establishment of euglycaemia. A second hypoglycaemia caused an additional fall. CONCLUSIONS/INTERPRETATION: Repeated hyperglycaemia events do not lead to any cumulative effects on blood electrolytes. However, repeated hypoglycaemias are cumulative with respect to K(+) levels due to a very slow recovery following hypoglycaemia. These results suggest that recurring hypoglycaemic events may lead to progressively lower K(+) levels despite rapid re-establishment of euglycaemia. This warrants close monitoring of plasma K(+) levels combined with continuous glucose monitoring particularly in patients under intensive insulin therapy who are subject to repeated hypoglycaemic episodes. TRIAL REGISTRATION: Clinicaltrial.gov NCT01060917.

New ways of insulin delivery.

The predominant number of papers published from the middle of 2009 to the middle of 2010 about alternative routes of insulin administration (ARIA) were still about inhaled insulin. Long-term experience with Exubera was the topic of a number of publications that are also of relevance for inhaled insulin in general. The clinical trials performed with AIR insulin by Eli Lilly were published in a supplement issue of one diabetes technology journal and most of these will be presented. A number of other publications (also one in a high ranked journal) about their inhaled insulin were from another company: MannKind. The driving force behind Technosphere insulin (TI) - which is the only one still in clinical development - is Al Mann; he has put a lot of his personal fortune in this development. We will know the opinion of the regulatory authorities about TI in the near future; however, I am personally relatively confident that the Food and Drug Administration will provide TI with market approval. The more critical question for me is: will diabetologists and patients jump on this product once it becomes commercially available? Will it become a commercial success? In view of many negative feelings in the scientific community about inhaled insulin, it might be of help that MannKind publish their studies with TI systematically. Acknowledging being a believer in this route of insulin administration myself, one has to state that Exubera and AIR insulin had not offered profound advantages in terms of pharmacokinetic (PK) and pharmacodynamic (PD) properties in comparison with subcutaneously (SC) applied regular human insulin (RHI) and rapid-acting insulin analogues. The time-action profiles of these inhaled insulins were more or less comparable with that of rapid-acting insulin analogues. This is clearly different with TI which exhibits a strong metabolic effect shortly after application and a rapid decline in the metabolic effect thereafter; probably the duration of action is even too short (see postprandial glycaemic excursions with test meals in the publication by Rosenstock et al. in The Lancet (1)). In the end a number of aspects are of relevance for the success of a given product; one key aspect is clearly the price. However, for patients also practical aspects (handling, need for regular pulmonary function test etc.) are of importance. We shall have to see how creatively MannKind will handle all such questions. Until now Al Mann and his colleagues were able to manage a number of challenges during the clinical development process successfully, so one can have hopes for the market success of TI. However, it is clear that at the same time, if TI fails like Exubera did before, this will be the end for pulmonary insulin in general. Not too many original publications presenting data from clinical trials were published in the last year when it comes to oral insulin (OI), nasal insulin or transdermal insulin developments; simply none with transdermal insulin. Also at the last international congresses not many studies about ARIA were presented. At least in part this might be still a reflection of the shockwaves that the failure of Exubera has sent out to pharmaceutical companies and venture capitalists; they are quite reluctant to invest in any of these developments. However, a considerable number of reviews (in some cases more than original papers!) were published about ARIA. These reviews are listed for completeness, but in most cases are not further commented. OI is still the area of research most companies are active in; however, in some cases it is not clear how active they really are (e.g. Diabetology). Nevertheless, at least some companies are quite active and progressed in their clinical development programme close to market approval, e.g. the large Indian company Biocon is in late phase 3 with IN-105 and the small Israel-based company Oramed is in phase 2b. It appears that other interesting OI developments (e.g. Diasome) were not very active in the last year; at least they have not published new study results. It is clear that for companies that produce insulin themselves (e.g. Biocon) the costs of the good are not of such relevance as for companies that have to buy it commercially. For the latter ones a low bioavailability/biopotency compared with SC insulin administration can be a real hurdle when it comes to the price of their product. Despite some publications about nasal insulin, the overall activity with this route of insulin administration appears to be low; the same holds true for transdermal insulin. Insulin pens have gained more scientific interest in recent years, which is also reflected by an increase in publications, starting from practically nil 10 years ago to a solid number of five to 10 papers per year nowadays. Besides ARIA there are also attempts to increase the speed of insulin absorption after injection into the skin by applying it not into the SC tissue but intradermally or by heating up the skin above the SC insulin depot. Reading a number of papers that were not included in this chapter because they do not present any clinical data but are novel developments tested only in animal experiments so far, the clear message is that there is definitely not a lack of creativity/imagination amongst scientists; each year a plethora of new ideas for insulin application show up. Unfortunately not too many make it towards a full clinical development. As long as there is not a single successful product on the market that is based on a given ARIA approach, this area of research will not mature. For many patients, avoiding the need for SC injections is attractive; however, as long as no clear 'advantage' can be demonstrated, reimbursement will be difficult to achieve. Living in the time of evidence-based medicine it is clear that 'relevant' clinical advantages must be proven. The question is what is relevant. Is it just an improvement in metabolic control (= decrease in HbA1c)? Can this also mean that more patients are willing to start insulin therapy earlier than with conventional SC insulin therapy? With TI we have a product that has improved pharmacological properties (also in comparison to Exubera) for coverage of prandial insulin requirements. Subsequently, in the clinical trials performed, postprandial glycaemic excursions were lower than with SC injection of RHI or rapid-acting insulin analogues. This only in part (if at all) results in an improved metabolic control in general (= lower HbA1c) (see below). The outlook for 2011 is that there are chances that we shall have an inhaled insulin product on the market. Probably also the first OI will be submitted to the regulatory authorities for market approval or will even be available in less regulated markets. In order to select all relevant publications about new ways of insulin delivery I performed a PUBMED search and also checked the table of contents of a number of journals that publish heavily in this area of research as well references in the publications I found for additional references. Selection of the manuscripts from all publications was predominately based on the fact whether they presented data from clinical studies or not. The selected studies were critically reviewed for novelty and appropriate study design etc. In some cases also reviews about a given topic were selected if they provide relevant novel insights.

New ways of insulin delivery.

When Exubera (EXU), the first inhaled insulin formulation to make it through the clinical development process, was introduced to the market some years ago it was hoped that this would be the first in a series of novel insulin formulations applied by this route. In addition, it was hoped that inhaled insulin would pave the way for other alternative routes of insulin administration (ARIA), i.e. oral insulin, nasal insulin or transdermal insulin to mention only some of the different attempts that have been studied in the last 90 years. The failure of EXU, i.e. its withdrawal from the market due to insufficient market success, was followed by the cessation of nearly all other attempts to develop inhaled insulin formulations. Currently there is only one company (MannKind) which moves sturdily ahead with their Technosphere insulin. This company has submitted an NDA for their product recently and hopes to bring it to the market by the end of 2010 or early 2011. Even if the product is able to pass the approval hurdles in the USA and Europe, this does not guarantee that it will become a market success. Many diabetologists were sceptical about the need/advantages of inhaled insulin/EXU from the start and the introduction of this product has raised even more scepticism. Reports about 'side effects' (development of lung cancer in patients treated with EXU) of inhaled insulin are also not helpful, even if the causality of the appearance of cancer with this type of insulin therapy is not proven. One of the very negative consequences of stopping EXU are the huge financial losses to Pfizer. The managers in charge in other pharmaceutical companies and also most venture capitalists are reluctant to invest in ARIA nowadays. This in turn means that many of the small companies that try to develop new forms of insulin administration have issues when they try to find a big brother and/or sufficient financial support. Clearly the economic crisis has further aggravated this issue. One can foresee that with most new ways of insulin delivery the bioavailability/biopotency will be lower than with subcutaneous (SC) insulin administration. This in turn requires that more insulin has to be applied to induce the same metabolic (blood glucose lowering) effect in patients with diabetes. If the costs of insulin are of relevance for the price (this clearly depends on the source of insulin the individual company has to use) the price of the product will be higher relative to standard SC insulin therapy. The question is, clearly, what are the advantages of the new product? In times when SC insulin administration was painful and cumbersome it was clear that the ease of swallowing an insulin tablet was a good argument for many patients. With the invention of thin insulin needles that make the SC injection practically pain free in most cases, this argument of being 'convenient' becomes of limited relevance. However, for many patients (especially the public) the avoidance of 'injection' is an argument. The question is, how much is the patient (society) willing to pay for such a psychological 'advantage'? Most probably additional clear-cut clinical advantages must be demonstrable to convince the payers to reimburse a new product, especially when the price is higher than that of SC insulin. If, for example, postprandial glycaemic excursions are considerably better controlled because the pharmacodynamic (PD) effects are better than with SC injection of rapid-acting insulin analogues (this might be possible with inhaled Technosphere insulin), this would be a clinically relevant argument. Without such advantages, new products will have no market success. Most probably it will not be until one of the various ARIA developments (e.g. nasal insulin) makes it into a financially attractive product (sufficient return on investment) that more money will flow again in this area of research. The search for relevant articles about new ways to deliver insulin did not reveal very many, especially on clinical studies. However, it is fascinating to see that the imagination about improvements in existing ways to deliver insulin (e.g. insulin pens) and also about novel ways to improve insulin absorption (e.g. local heating of the injection site) is still there. At the same time the above-mentioned considerations (coming more from the viewpoint of pharmaceutical companies and more market oriented) appear not to be the focus of many scientists in pharmacological research institutes. Otherwise it is difficult to understand why every year a number of new oral insulin formulations are published in pharmacological journals, reporting impressive data from animal studies (mainly performed on rats), but only a very limited number of these are transferred to the clinical development process. It is well known that most drugs fail during the clinical development process and the resources of pharmaceutical companies that are willing to invest in, for example, oral insulin are very limited. Small companies tend to make a lot of smoke out of a little fire to gain access to these resources. Unfortunately, the limited financial resources also hamper the design and performance of pre-clinical experiments and clinical studies. The consequence is that many of the study results presented are inconclusive (to phrase it carefully). One good study that proves that a given approach works - or shows convincingly that it does not work - would be much better than a number of small studies. Sometimes one has the impression that this is done on purpose to show some activity and keep the company alive. Without a more stringent approach there is a high risk that many of the current developments will never make it into an available clinical product. These comments are not intended to be destructive but to strengthen a thorough scientific approach and to induce a more realistic view of the prospects: most probably an oral insulin pill will not be on the market next year! Nevertheless, this is the route of insulin administration where I would put my money (if I had enough). Also in this area of research it is not easy to make statements about which approaches are valid and will make it to a product. The fact that some large pharmaceutical companies are active in this area indicates that they also believe that oral insulin is the hottest candidate of the next ARIA that will come to the market.

Glucose monitoring by microdialysis: performance in a multicentre study.

AIMS: The aim of this study was to assess the performance of the Continuous Research Tool (CRT) in a multicentre clinical-experimental study. METHODS: Three patient groups totalling 28 subjects with diabetes [group A 10 Type 1 (Ulm), group B 10 Type 1 (Neuss), group C eight Type 2 (Aarhus)] participated in this trial. Two CRT microdialysis probes were inserted in parallel in the abdominal subcutaneous tissue for 120 h in each subject. In subjects in group A, glucose excursions were induced on one study day and those in group B underwent a glucose clamp (eu-, hypo- or hyperglycaemic) on one study day. CRT data were calibrated once with a retrospective calibration model based on a run-in time of 24 h and three blood glucose measurements per day. RESULTS: All analysable experiments, covering a broad range of blood glucose values, yielded highly accurate data for the complete experimental time with a mean relative absolute difference of 12.8 +/- 6.0% and a predictive residual error sum of squares of 15.6 +/- 6.3 (mean +/- SD). Of all measurement results, 98.2% were in zones A and B of the error grid analysis. The average absolute differences were 1.14 mmol/l for Type 1 and 0.88 mmol/l for Type 2 diabetic patients. Relative absolute differences were 16.0% for Type 1 and 12.6% for Type 2 diabetic patients. CONCLUSIONS: These results demonstrate that this microdialysis system allows reliable continuous glucose monitoring in patients with diabetes of either type.

Renal glucose excretion and tubular reabsorption rate related to blood glucose in subjects with type 2 diabetes with a critical reappraisal of the "renal glucose threshold" model.

Until today a "renal threshold for glucose" is described in most medical textbooks. Notwithstanding, low glucose levels are detectable in urine even under euglycaemic conditions - a phenomenon which was observed already in 1904 and labelled as "basal glucosuria". We aimed to characterise renal glucose transport during various steady-state blood glucose levels. Twenty-two subjects with type 2 diabetes and normal renal function underwent two 5-period hyperglycaemic glucose-clamps with blood glucose target levels between 7.8 and 13.3 mmol x l(-1). A virtual renal threshold for glucose excretion (VRT (G)) was calculated for every subject as the highest blood glucose concentration during the glucose-clamps associated with a concomitant urinary glucose level of <2.8 mmol x l(-1). VRT (G) of subjects was classified as low, medium, and high. Each urine sample contained a detectable amount of glucose with a minimal urinary glucose concentration of 0.73 mmol x l(-1). Median VRT (G) was 11.0 mmol x l(-1), ranging from 7.8 and 12.1 mmol x l(-1). With increasing blood glucose renal glucose excretion increased in each subject - but varied considerably between subjects. For example, at a blood glucose concentration of 11 mmol x l(-1) renal glucose excretion ranged from 163 micromol x min(-1) to 25 micromol x min(-1) in subjects exhibiting a low to high VRT (G), thus showing a variability >factor 6. This study reinforces the rejection of the concept of a renal threshold for glucose. Instead, this study shows a substantial variability of renal glucose excretion between subjects with type 2 diabetes.

Pharmacokinetics and linear exposure of AFRESA compared with the subcutaneous injection of regular human insulin.

AIM: AFRESA [Technosphere Insulin (TI); MannKind Corporation, Valencia, CA], a dry powder preparation of regular human insulin (RHI), utilizes a novel and versatile drug carrier platform that enables pulmonary administration of medications typically administered by injection. The aim of this study was to compare the pharmacokinetic (PK) and pharmacodynamic (PD) parameters of three different inhaled doses of TI with those of subcutaneous (s.c.) RHI. METHODS: This randomized, open-label, four-way crossover study of 11 healthy, non-smoking volunteers evaluated PK and PD profiles following single inhalations of 25, 50 or 100 U TI and 10 IU RHI administered subcutaneously using a euglycaemic clamp technique. RESULTS: Following inhalation of TI, peak insulin concentrations (C(max)) were achieved approximately 2 h earlier than with RHI (12-17 min for TI vs. 134 min for RHI). Area under the insulin concentration-time curve (AUC) and insulin C(max) values increased with increasing TI dose. Insulin exposure, as measured by AUC, was found to be linear over the dose range studied. Compared with s.c. RHI, TI at doses of 25, 50 and 100 U showed a relative bioavailability of 25, 23 and 21%, respectively. The maximum bioeffect, as measured by the glucose infusion rate, occurred approximately 2 h earlier for all three TI doses (42, 50 and 58 min, respectively) than for s.c. RHI (171 min). No treatment-related adverse events were reported with TI. CONCLUSION: TI is an inhaled insulin with a more rapid absorption and a more rapid elimination than subcutaneously administered RHI, resulting in a quick onset and short duration of action. Insulin exposure following TI administration was found to be linear over the dose range of 25-100 U.