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Concept: Rosiglitazone

225

 To assess the risks of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia in patients with type 2 diabetes associated with prescribed diabetes drugs, particularly newer agents including gliptins or glitazones (thiazolidinediones).

Concepts: Diabetes mellitus type 2, Diabetes mellitus, Insulin resistance, Anti-diabetic drug, Sulfonylurea, Pioglitazone, Thiazolidinedione, Rosiglitazone

24

A rapid, simple, and precise RPLC method was developed for the simultaneous determination of the widely used oral antidiabetic, metformin hydrochloride (MTF), with some commonly coadministered oral antidiabetics from different pharmacological classes-glipizide (GPZ), pioglitazone hydrochloride (PGZ), glimepiride (GLM), and repaglinide (RPG)-in bulk, laboratoryprepared mixtures and pharmaceutical formulations in the presence of metformin-reported impurity [1-cyanoguanidine (CNG)]. Chromatographic separation was achieved using isocratic elution mode with a mobile phase of acetonitrile: 0.02 M potassium dihydrogen phosphate (pH 3.17; 50-50, v/v) flowing through a CN Phenomenex column (Phenosphere Next, 250 × 4.6 mm, 5 μm) at a rate of 1.5 mL/min at ambient temperature. UV detection was carried out at 220 nm. The method was validated according to International Conference on Harmonization guidelines. Linearity, accuracy, and precision were satisfactory for concentration ranges: 0.175-350 μg/mL for MTF, 0.0525-105 μg/mL for GPZ, 0.125-250 μg/mL for PGZ, and 0.05-100 μg/mL for GLM and RPG. Correlation coefficients were ˃0.99 for all analytes. LOQs were 0.009 μg/mL for MTF, 0.009 μg/mL for GPZ, 0.04 μg/mL for GLM, 0.124 μg/mL for PGZ, and 0.044 μg/mL for RPG. The developed method is specific, accurate, and suitable for the QC and routine analysis of the cited drugs in their pharmaceutical products.

Concepts: Anti-diabetic drug, Sulfonylurea, Metformin, Pioglitazone, Rosiglitazone

22

Loss-of-function mutations inPPARGcause familial partial lipodystrophy type 3 (FPLD3) and severe metabolic disease in many cases. Missense mutations inPPARGare present in ∼1:500 people. Whilst mutations are often binarily classified as ‘benign’ or ‘deleterious’, prospective functional classification of all missensePPARGvariants suggests that their impact is graded. Furthermore, in testing novel mutations with both prototypic ‘endogenous’ (e.g. prostaglandin J2 (PGJ2)) and synthetic ligands (thiazolidinediones, tyrosine agonists), we observed that synthetic agonists selectively rescue function of some PPARγ mutants. Here, we report FPLD3 patients, harbouring two such PPARγ mutations (R308P, A261E). Both PPARγ mutants exhibit negligible constitutive or PGJ2-induced transcriptional activity but respond readily to synthetic agonistsin vitro, with structural modelling providing a basis for such differential ligand-dependent responsiveness. Concordant with this, dramatic clinical improvement was seen following pioglitazone treatment of the patient with R308P mutant PPARγ. A patient with A261E mutant PPARγ also responded beneficially to rosiglitazone, though cardiomyopathy precluded prolonged thiazolidinedione use. These observations indicate that detailed structural and functional classification can be used to inform therapeutic decisions in patients withPPARGmutations.

Concepts: Mutation, Mutant, Pioglitazone, Point mutation, Missense mutation, Thiazolidinedione, Rosiglitazone, Thiazolidinediones

4

Metabolic syndrome (MetS) is thought to influence several autoimmune diseases, including multiple sclerosis (MS). Anti-inflammatory effects of treatments used for MetS, such as metformin hydrochloride and pioglitazone hydrochloride, have been demonstrated, although clinical evidence supporting use of these treatments in MS is lacking.

Concepts: Diabetes mellitus type 2, Insulin resistance, Multiple sclerosis, Anti-diabetic drug, Metformin, Pioglitazone, Non-alcoholic fatty liver disease, Rosiglitazone

2

In the Guidance for Industry from the Food and Drug Administration in 2008, excess cardiovascular risk should be ruled out in trials of all new antidiabetic drugs; however, relatively few studies have focused on cardiovascular safety with antidiabetic drug use. We aimed to examine mortality and cardiovascular risk using a network meta-analysis. We searched the Medline, Embase, Cochrane, and ClinicalTrials.gov registry databases in March 2016 to identify randomized controlled trials reporting cardiovascular risk with the following oral antidiabetic drugs: metformin, sulfonylureas, thiazolidinedione (TZD), dipeptidyl peptidase-4 (DPP4) inhibitors, and sodium-glucose co-transporter-2 (SGLT2) inhibitors. We assessed the differences in the risks of all-cause mortality, cardiovascular-related mortality, acute coronary syndrome (ACS), and myocardial infarction (MI) among antidiabetic drugs with fixed effect models for direct pairwise comparisons and Bayesian network meta-analyses to integrate direct and indirect comparisons. Of the 101,183 patients in 73 randomized controlled trials, 3,434 (3.4%) died. The relative risks of all-cause mortality with SGLT2 inhibitor use were 0.68 (95% credible interval: 0.57-0.80), 0.74 (0.49-1.10), 0.63 (0.46-0.87), 0.71 (0.55-0.90), and 0.65 (0.54-0.78), compared with placebo, metformin, sulfonylurea, TZD, and DPP4 inhibitor, respectively. The relative risks of cardiovascular-related mortality with SGLT2 inhibitor use were 0.61 (0.50-0.76), 0.81(0.36-1.90), 0.52(0.31-0.88), 0.66(0.49-0.91), and 0.61(0.48-0.77), compared with placebo, metformin, sulfonylurea, TZD, and DPP4 inhibitor, respectively. The relative risks of ACS with SGLT2 inhibitor use was consistent with that of all-cause mortality. SGLT2 inhibitor use was associated with a lower risk of ACS than the other OADs and placebo. The relative risks of MI with SGLT2 inhibitor use were 0.77 (0.63-0.93) and 0.75 (0.60-0.94), compared with placebo and DPP4 inhibitor, respectively. The currently available data provide the evidence of cardiovascular benefit from use of SGLT2 inhibitors to patients with type 2 diabetes, although additional results from ongoing studies will be pivotal.

Concepts: Myocardial infarction, Diabetes mellitus, Anti-diabetic drug, Metformin, Pioglitazone, Thiazolidinedione, Exenatide, Rosiglitazone

2

AIMS/HYPOTHESIS: Current drug labels for thiazolidinediones (TZDs) warn of increased fractures, predominantly for distal fractures in women. We examined whether exposure to TZDs affects hip fracture in women and men and compared the risk to that found with other drugs used in diabetes. METHODS: Using a nationwide database of prescriptions, hospital admissions and deaths in those with type 2 diabetes in Scotland we calculated TZD exposure among 206,672 individuals. Discrete-time failure analysis was used to model the effect of cumulative drug exposure on hip fracture during 1999-2008. RESULTS: There were 176 hip fractures among 37,479 exposed individuals. Hip fracture risk increased with cumulative exposure to TZD: OR per year of exposure 1.18 (95% CI 1.09, 1.28; p = 3 × 10(-5)), adjusted for age, sex and calendar month. Hip fracture increased with cumulative exposure in both men (OR 1.20; 95% CI 1.03, 1.41) and women (OR 1.18; 95% CI 1.07, 1.29) and risks were similar for pioglitazone (OR 1.18) and rosiglitazone (OR 1.16). The association was similar when adjusted for exposure to other drugs for diabetes and for other potential confounders. There was no association of hip fracture with cumulative exposure to sulfonylureas, metformin or insulin in this analysis. The 90-day mortality associated with hip fractures was similar in ever-users of TZD (15%) and in never-users (13%). CONCLUSIONS/INTERPRETATION: Hip fracture is a severe adverse effect with TZDs, affecting both sexes; labels should be changed to warn of this. The excess mortality is at least as much as expected from the reported association of pioglitazone with bladder cancer.

Concepts: Diabetes mellitus type 2, Diabetes mellitus, Insulin resistance, Anti-diabetic drug, Metformin, Pioglitazone, Thiazolidinedione, Rosiglitazone

1

To examine and compare risks of serious hypoglycemia among antidiabetic monotherapy-treated adults receiving metformin, a sulfonylurea, a meglitinide, or a thiazolidinedione.

Concepts: Cohort study, Diabetes mellitus, Anti-diabetic drug, Sulfonylurea, Metformin, Pioglitazone, Exenatide, Rosiglitazone

0

Heart failure (HF) is a common complication in patients with type 2 diabetes and it is closely associated with high morbidity and mortality rate. The incidence of cardiovascular events in patients with diabetes is related to high levels of glycemia, expressed by increase of HbA1c levels. However, there is little evidence to indicate that glycemic control can reduce the incidence of HF events in this population. Recently, several new antidiabetic drugs have been proposed although the exact clinical impact on heart failure occurrence and deterioration is under debate. Most common oral antidiabetic medication such as SGLT2, GLP-1 receptor agonist, metformin, and DPP4 inhibitor revealed peculiar metabolic and biomolecular signal effects. Moreover, the negative effects of thiazolidinediones on HF prognosis, on cardiac function, and exercise tolerance is of great interest. Conversely, several studies on GLP-1RA have highlighted many positive effects on cardiac myocytes, reducing apoptosis through cAMP/PKA/CRCB-mediated pathways protecting against oxidative stress. DPP-4 inhibitors have a controversial effect: saxagliptin and alogliptin may increase the risk of HF as opposed to vildagliptin and sitagliptin. Metformin increases myocardial ATP levels due to activation of 5-AMPK and this could explain the positive link between the drug and events rate reduction in diabetic patients with HF. The more interesting class of new drugs is SGLT2 inhibitors, that seems to have a positive effect on cardiac function by 38% reduction of HF incidence and mortality with empagliflozin treatment. In this review, we would analyze the specific effects of each class so as to better elucidate the clinical impact of antidiabetic drug on HF for guiding the clinicians in the choice of a best individualized therapy.

Concepts: Diabetes mellitus, Anti-diabetic drug, Metformin, Pioglitazone, Anti-diabetic drugs, Sitagliptin, Thiazolidinedione, Rosiglitazone

0

Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor superfamily. It functions as a ligand-activated transcription factor and plays important roles in the regulation of adipocyte differentiation, insulin resistance, and inflammation. Here, we report the crystal structures of PPARγ in complex with lobeglitazone, a novel PPARγ agonist, and with rosiglitazone for comparison. The thiazolidinedione (TZD) moiety of lobeglitazone occupies the canonical ligand-binding pocket near the activation function-2 (AF-2) helix (i.e., helix H12) in ligand-binding domain as the TZD moiety of rosiglitazone does. However, the elongated p-methoxyphenol moiety of lobeglitazone interacts with the hydrophobic pocket near the alternate binding site of PPARγ. The extended interaction of lobeglitazone with the hydrophobic pocket enhances its binding affinity and could affect the cyclin-dependent kinase 5 (Cdk5)-mediated phosphorylation of PPARγ at Ser245 (in PPARγ1 numbering; Ser273 in PPARγ2 numbering). Lobeglitazone inhibited the phosphorylation of PPARγ at Ser245 in a dose-dependent manner and exhibited a better inhibitory effect on Ser245 phosphorylation than rosiglitazone did. Our study provides new structural insights into the PPARγ regulation by TZD drugs and could be useful for the discovery of new PPARγ ligands as an anti-diabetic drug, minimizing known side effects.

Concepts: Signal transduction, Peroxisome proliferator-activated receptor, Diabetes mellitus, Anti-diabetic drug, Pioglitazone, Nuclear receptor, Thiazolidinedione, Rosiglitazone

0

Inter-individual variability in pharmacokinetics can lead to unexpected side effects and treatment failure, and is therefore an important factor in drug development. CYP2C8 is a major drug-metabolizing enzyme known to be involved in the metabolism of over 100 drugs. In this study, we predicted the inter-individual variability in AUC/Dose of CYP2C8 substrates in healthy volunteers using the Monte Carlo simulation. Inter-individual variability in the hepatic intrinsic clearance of CYP2C8 substrates (CLint,h,2C8) was estimated from the inter-individual variability in pharmacokinetics of pioglitazone, which is a major CYP2C8 substrate. The coefficient of variation (CV) of CLint,h,2C8 was estimated to be 40%. Using this value, the CVs of AUC/Dose of other major CYP2C8 substrates, rosiglitazone and amodiaquine, were predicted to validate the estimated CV of CLint,h,2C8. As a result, the reported CVs of both substrates were within the 2.5-97.5 percentile range of the predicted CVs. Furthermore, the CVs of AUC/Dose of the CYP2C8 substrates loperamide and chloroquine, which are affected by renal clearance, were also successfully predicted. Combining this value with previously reported CVs of other CYPs, we were able to successfully predict the inter-individual variability in pharmacokinetics of various drugs in clinical.

Concepts: Scientific method, Pharmacology, Enzyme, Prediction, Futurology, Prophecy, Monte Carlo, Rosiglitazone