Evolution of pharmacological obesity treatments: focus on adverse side-effect profiles.

Pharmacotherapy directed toward reducing body weight may provide benefits for both curbing obesity and lowering the risk of obesity-associated comorbidities; however, many weight loss medications have been withdrawn from the market because of serious adverse effects. Examples include pulmonary hypertension (aminorex), cardiovascular toxicity, e.g. flenfluramine-induced valvopathy, stroke [phenylpropanolamine (PPA)], excess non-fatal cardiovascular events (sibutramine), and neuro-psychiatric issues (rimonabant; approved in Europe, but not in the USA). This negative experience has helped mould the current drug development and approval process for new anti-obesity drugs. Differences between the US Food and Drug Administration (FDA) and the European Medicines Agency, however, in perceptions of risk-benefit considerations for individual drugs have resulted in discrepancies in approval and/or withdrawal of weight-reducing medications. Thus, two drugs recently approved by the FDA, i.e. lorcaserin and phentermine + topiramate extended release, are not available in Europe. In contrast, naltrexone sustained release (SR)/bupropion SR received FDA approval, and liraglutide 3.0 mg was recently approved in both the USA and Europe. Regulatory strategies adopted by the FDA to manage the potential for uncommon but potentially serious post-marketing toxicity include: (i) risk evaluation and mitigation strategy programmes; (ii) stipulating post-marketing safety trials; (iii) considering responder rates and limiting cumulative exposure by discontinuation if weight loss is not attained within a reasonable timeframe; and (iv) requiring large cardiovascular outcome trials before or after approval. We chronicle the adverse effects of anti-obesity pharmacotherapy and consider how the history of high-profile toxicity issues has shaped the current regulatory landscape for new and future weight-reducing drugs.

Effect of exogenously administered glucagon versus spontaneous endogenous counter-regulation on glycaemic recovery from insulin-induced hypoglycaemia in patients with type 2 diabetes treated with a novel glucokinase activator, AZD1656, and metformin.

AIMS: To study the effect of exogenous i.m. glucagon on recovery from controlled insulin-induced hypoglycaemia in patients with type 2 diabetes treated with the novel glucokinase activator AZD1656, in combination with metformin. METHODS: This was a single-centre randomized, open, two-way crossover phase I, automated glucose clamp (Biostator(®); Life Science Instruments, Elkhart, MD, USA) study (NCT00817271) in eight patients (seven men and one woman, mean age 58.6 years, body mass index 28.1 kg/m(2)). All patients received a stable dose of metformin twice daily, ranging from 1000 to 2250 mg. A 2-day titration phase commenced with 40 mg AZD1656 twice daily, escalating to 80 mg twice daily if tolerated. This was followed by a single dose of 80 or 160 mg AZD1656, administered on days 5 and 8 when metabolic studies were performed. After an overnight fast on days 5 and 8, controlled hypoglycaemia was induced using an exogenous i.v. infusion of insulin. Plasma glucose was lowered in a stepwise fashion over 3 h to attain a target nadir of 2.7 mmol/l. This was sustained for 30 min, at the end of which the hypoglycaemic clamp was released. In random sequence, patients either received an i.m. injection of 1 mg glucagon or were allowed to recover from hypoglycaemia by endogenous counter-regulation. To avoid prolonged hypoglycaemia, a reverse glucose clamp was applied from 4 to 6 h post-dose. RESULTS: Three patients received 40 mg AZD1656 twice daily and five patients 80 mg twice daily. Mean plasma glucose at 20 min after release of the hypoglycaemic clamp was significantly lower (3.1 ± 0.3 mmol/l) for AZD1656 alone than for AZD1656 + glucagon (4.9 ± 0.8 mmol/l; p < 0.001 between the groups). Catecholamine and cortisol responses were similar on the AZD1656 + glucagon and AZD alone study days. Growth hormone response was 18% lower for AZD1656 alone (p = 0.01), consistent with the effect of a pharmacological dose of glucagon on growth hormone secretion. No safety or tolerability concerns were observed during treatment with AZ1656. CONCLUSIONS: Exogenous glucagon was effective as a rescue treatment for hypoglycaemia induced during treatment with AZD1656, given in combination with metformin in patients with type 2 diabetes.

Insulin resistance: a risk marker for disease and disability in the older person.

Clinical metabolic studies have demonstrated that insulin action declines progressively with age in humans. In addition to its close association with Type 2 diabetes, which reduces life expectancy in older people, age-related insulin resistance is implicated in pathogenesis of several highly prevalent disorders for which ageing is a major risk factor. These include atherosclerotic cardiovascular disease, dementia, frailty and cancer. Accordingly, insulin resistance may be viewed as biomarker of age-related ill health and reduced lifespan. The rapidly rising number of older people, coupled with a high prevalence of insulin resistance resulting from obesity and sedentary lifestyles, presents unprecedented public health and societal challenges. Studies of centenarians have shown that preserved whole-body sensitivity to insulin is associated with longevity. The mechanisms through which insulin action is associated with age-related diseases remain unclear. Changes in body composition, i.e. sarcopenia and excess adiposity, may be more potent than age per se. Moreover, the impact of insulin resistance has been difficult to disentangle from the clustering of vascular risk factors that co-segregate with the insulin resistance-hyperinsulinaemia complex. Potentially modifiable mediators of age-related changes in insulin sensitivity include alterations in adipocytokines, impaired skeletal myocyte mitochondrial function and brown fat activity. The hypothesis that improving or maintaining insulin sensitivity preserves health and extends lifespan merits further evaluation. Practical non-pharmacological interventions directed against age-related insulin resistance remain underdeveloped. Novel metabolically active pharmacological agents with theoretical implications for some age-related disorders are entering clinical trials. However, recent adverse experiences with the thiazolidinediones suggest the need for a cautious approach to the use of insulin sensitizing drugs in older people. This could be particularly important in the absence of diabetes where the risk to benefit analysis may be less favourable.

Diabetes medication patient safety incident reports to the National Reporting and Learning Service: the care home setting.

AIMS: To analyse adverse drug events in older people with diabetes in the care home setting via incident reports obtained from the National Reporting and Learning Service. METHODS: A Freedom of Information request was made to the National Reporting and Learning Service via the National Patient Safety Agency. Within the National Reporting and Learning Service, reports on diabetes within the category of 'medication' using the location limiter of 'hospice or nursing home or residential home' were searched. We requested information about the number and nature of adverse drug event reports that had been received in relation to diabetes. The data were subdivided into reports (1) relating to insulin therapy and (2) oral glucose-lowering agents. RESULTS: Data were collected between 1 January 2005 and 31 December 2009. There were 684 reports related to insulin and 84 incidents related to oral glucose-lowering agents. The most common error category with both types of drug therapy was wrong or unclear dose: 173 reports for insulin, including one death, and 20 reports for oral therapy. CONCLUSIONS: Residents with diabetes in care homes are potentially at risk of harm from adverse drug events pertaining to insulin and oral glucose-lowering agents. Because of under-reporting, our data most likely represent only a fraction of events.

Diastolic function is strongly and independently associated with cardiorespiratory fitness in central obesity.

Cardiorespiratory fitness [maximal O2 consumption (VO2max)] is an independent risk factor for type 2 diabetes; but in individuals at risk, factors influencing VO2max are poorly understood. We tested the hypothesis that VO2max is associated with diastolic function [subendocardial variability ratio (SEVR), %], as diastolic function influences myocardial perfusion. We studied 47 men and women with central obesity without diabetes. We measured fitness (VO2max) by treadmill testing and diastolic function (SEVR%) by pulse-wave analysis. We measured other factors influencing this relationship: insulin sensitivity [whole body glucose uptake-to-insulin concentration ratio (M/I)] by hyperinsulinemic euglycemic clamp, fatness by MR imaging and dual-energy X-ray absorptiometry, physical activity energy expenditure (metabolic equivalents of tasks) by the Sensewear Pro2 device, and muscle microvascular exchange capacity (capillary filtration coefficient) by venous plethysmography. Mean age of the subjects was 51+/-9 (SD) yr. VO2max was associated with SEVR% (r=0.50, P=0.001), fatness (r=-0.39, P=0.008), and HbA1c (r=-0.35, P=0.018), but not with whole body glucose uptake-to-insulin concentration ratio, metabolic equivalents of tasks, or capillary filtration coefficient. In regression modeling with age, sex, fatness, and SEVR% as explanatory variables, only age, sex, and SEVR% were independently associated with VO2max (SEVR%--standardized B coefficient=0.37, 95% confidence interval=0.003-0.18, P=0.007). This model identified 46% of the variance in VO2max (R2=0.46, P=0.0001). There was a strong, independent association between VO2max and a measure of diastolic function in sedentary individuals with central obesity.

Skeletal muscle microvascular exchange capacity is associated with hyperglycaemia in subjects with central obesity.

AIMS: Poor glycaemic control is associated with increased risk of microvascular disease in various organs including the eye and kidney, but the relationship between glycated haemoglobin (HbA(1c)) and microvascular function in skeletal muscle has not been described. We tested the association between HbA(1c) and a measure of microvascular exchange capacity (K(f)) in skeletal muscle in people with central obesity at risk of developing Type 2 diabetes. METHODS: Microvascular function was measured in 28 women and 19 men [mean (+/- sd) age 51 +/- 9 years] with central obesity who did not have diabetes. We estimated insulin sensitivity by hyperinsulinaemic-euglycaemic clamp, visceral and total fatness by magnetic resonance imaging, fitness (VO(2) max by treadmill testing), physical activity energy expenditure [metabolic equivalents of tasks (METS) by use of the SenseWear Pro armband] and skeletal muscle microvascular exchange capacity (K(f)) by venous occlusion plethysmography. RESULTS: In regression modelling, age, sex and fasting plasma glucose accounted for 30.5% of the variance in HbA(1c) (r(2) = 0.31, P = 0.001). Adding K(f) to this model explained an additional 26.5% of the variance in HbA(1c) (r(2) = 0.57, P = 0.0001 and K(f) was strongly and independently associated with HbA(1c) (standardized B coefficient -0.45 (95% confidence interval -0.19, -0.06), P = 0.001). CONCLUSIONS: We found a strong negative independent association between a measure of skeletal muscle microvascular exchange capacity (K(f)) and HbA(1c). K(f) was associated with almost as much of the variance in HbA(1c) as fasting plasma glucose.

Practical guidance on intensification of insulin therapy with BIAsp 30: a consensus statement.

BACKGROUND: Basal insulin and premix insulin are commonly prescribed first-line insulin therapies for patients failing to maintain glycaemic control on oral therapy. When control on these insulins starts to drift, premix analogues, such as biphasic insulin aspart 30/70 (BIAsp 30), are a simple and effective tool for intensification as they can be injected up to three-times daily (TID). However, at present, international recommendations for intensification of insulin therapy using premix analogues are limited and specific guidance on dosing is not available for many scenarios. METHODS: In October 2008, an international expert panel met to review the current guidelines for insulin intensification with BIAsp 30 in patients with type 2 diabetes, with the aim of developing practical guidance for general and specialist practitioners. RESULTS: Simple treatment algorithms have been developed for (i) patients on basal insulin (human or analogue) once daily or twice daily (BID) who need intensification to BIAsp 30 BID, and (ii) patients on BIAsp 30 once daily or BID who can be intensified to BIAsp 30 BID or TID. As well as these algorithms, specific guidance has been provided on dose transfer (from basal insulin to BIAsp 30), dose split (when intensifying from once daily to BID), and combination oral therapies. In addition, a guide to dose titration is included. CONCLUSIONS: The guidelines presented here should enable general or specialist practitioners to use BIAsp 30 to intensify the insulin therapy of patients failing on basal insulin or BIAsp 30 once or twice daily.

Adipocytokines, sex hormones, and cardiovascular risk factors in postmenopausal women: factor analysis of the Rancho Bernardo study.

Steroid sex hormones modulate the expression of adipocytokines implicated in the pathogenesis of athero-thrombotic cardiovascular disease. We used exploratory factor analysis to search for latent associations between circulating sex steroid hormones, adipocytokines, and cardiovascular risk factors in a well-characterized cohort of postmenopausal women. Among participants in the Rancho Bernardo community study we identified 515 Caucasian women with a mean age of 74+/-8 years and mean body mass index of 24.2+/-3.7 kg/m(2). All had intact ovaries and none was using estrogen therapy. We constructed models aiming for structural clarity and high loading of variables on individual factors. Total adiponectin loaded with major lipid subfractions (low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and fasting triglycerides) and with sex hormone-binding globulin. Leptin loaded with central obesity (waist circumference) and fasting insulin levels. Neither adipocytokine loaded with total or bioavailable testosterone or with estradiol or dehydroepiandrosterone sulfate. Sex hormones consistently loaded together on a separate factor; this co-segregation was not influenced by body mass index. Exclusion of women with diabetes did not alter these observations. In conclusion, we identified evidence of latent associations between adipocytokines and a range of cardiovascular risk factors in postmenopausal women. Our results suggest that cardiovascular risk in older women may be modulated through a hitherto unrecognized association between adiponectin, lipid subfractions, and sex hormone bioavailability.

The efficacy of self-monitoring of blood glucose in the management of patients with type 2 diabetes treated with a gliclazide modified release-based regimen. A multicentre, randomized, parallel-group, 6-month evaluation (DINAMIC 1 study).

AIM: To determine if therapeutic management programmes for type 2 diabetes that include self-monitoring of blood glucose (SMBG) result in greater reductions in glycated haemoglobin (HbA1c) compared with programmes without SMBG in non-insulin requiring patients. METHODS: Multicentre, randomized, parallel-group trial. A total of 610 patients were randomized to SMBG or non-SMBG groups. Patients in both groups received the same oral antidiabetic therapy using a gliclazide modified release (MR)-based regimen for 27 weeks. The primary efficacy end-point was the difference between groups in HbA1c at the end of observation. RESULTS: A total of 610 patients were randomized: 311 to the SMBG group and 299 to the non-SMBG group. HbA1c decreased from 8.12 to 6.95% in the SMBG group and from 8.12 to 7.20% in the non-SMBG group; between-group difference was 0.25% (95% CI: 0.06, 1.03; p = 0.0097). Symptoms suggestive of mild to moderate hypoglycaemia was the most commonly reported adverse event, reported by 27 (8.7%) and 21 (7.0%) patients in the SMBG and non-SMBG groups, respectively; the incidence of symptomatic hypoglycaemia was lower in the SMBG group. CONCLUSION: In patients with type 2 diabetes, the application of SMBG as an adjunct to oral antidiabetic agent therapy results in further reductions in HbA1c.

Type 2 diabetes, psoriasis and thiazolidinediones.

Thiazolidinediones, synthetic ligands for the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) receptor, are insulin-sensitizing drugs licensed for use in selected patients with type 2 diabetes mellitus. The potential therapeutic applications of the thiazolidinediones extend to other clinical specialties such as dermatology. Rosiglitazone and pioglitazone are being evaluated for the treatment of psoriasis. Type 2 diabetes and psoriasis may coexist prompting speculation that dual benefits might accrue for patients with both conditions. A recent open pilot study suggests that oral pioglitazone may be beneficial for moderate chronic plaque psoriasis. However, changes in antidiabetic medication must be made in the knowledge of the cautions and contraindications to oral agents as well as the impact on metabolic control. Further studies are required before the use of thiazolidinediones for psoriasis can be advocated.

Metabolic and hormonal effects of tacrolimus (FK506) or cyclosporin immunosuppression following renal transplantation.

Twelve renal transplant recipients randomised to receive immunosuppression with either tacrolimus (FK506) or cyclosporin underwent oral glucose tolerance tests (OGTT) a median of 8 months (range 7-9) after transplantation. Six healthy subjects acted as controls. Compared with the controls, both transplant groups had significantly elevated fasting (p < 0.05 for both groups) and postprandial (p < 0.001 for tacrolimus and p < 0.05 for cyclosporin) blood glucose concentrations. Fasting hyperinsulinaemia was observed in both transplant groups (p < 0.05) relative to the control subjects. Glucose-stimulated plasma immunoreactive insulin concentrations in the tacrolimus-treatment group were significantly higher than in the cyclosporin group (p < 0.05) and the controls (p < 0.001). Postprandial blood alanine concentrations were also significantly elevated in the tacrolimus group compared with both the controls (p < 0.001) and cyclosporin-treated patients (p < 0.001). The raised insulin concentrations with normal or increased blood glucose concentrations after renal transplantation suggests that insulin resistance was more marked in patients receiving tacrolimus-based immunosuppression.