A drug and disease model for lixisenatide, a GLP-1 receptor agonist in type 2 diabetes

Polymeric microparticle systems for modified release of glucagon-like-peptide-1 receptor agonists

Type 2 diabetes is a fast-growing worldwide epidemic. Despite the multiple therapies available to treat type 2 diabetes, the disease is not correctly managed in over half of patients, mainly due to non-compliance with prescribed treatment regimes. The development of analogues to the glucagon-like peptide 1 (GLP-1) has resulted in the extension of its half-life and associated benefits. Further benefits in the use of peptide-based GLP-1 receptor agonists have been achieved by the use of controlled-release systems based on polymeric microparticles. In this review, we focus on commercially available formulations and others that remain in development, discussing the preparation methods and the relationship between in vitro and in vivo kinetic release behaviours.

Lixisenatide, a Once-Daily Prandial Glucagon-Like Peptide-1 Receptor Agonist for the Treatment of Adults with Type 2 Diabetes

Lixisenatide, a short-acting glucagon-like peptide-1 receptor agonist (GLP-1 RA), has been available in Europe since 2013 and was recently approved in the United States for the treatment of type 2 diabetes (T2D) as an adjunct to diet and exercise. The objective of this systematic review is to describe the pharmacology, pharmacokinetics, safety, and efficacy of lixisenatide in patients with T2D. We conducted a search of the EMBASE database, limited to human studies with abstracts available in English. Published conference abstracts, limited to the American Diabetes Association (ADA) and the European Association for the Study of Diabetes meetings in 2015, as well as abstracts presented at the ADA meeting in 2016, were also screened. The abstracts retrieved were assessed for relevance; review articles and meta-analyses focusing on GLP-1 RAs as a class were excluded. Lixisenatide induced mean reductions of 0.46-0.99% in glycated hemoglobin A_1c (Hb_A1c ), 55.86-143.43 mg/dl in 2-hour postprandial glucose (PPG) levels, and 56.58-127.75 mg/dl in mealtime glucose level variations. Changes in fasting plasma glucose (FPG) levels and weight ranged from -21.98 to +5.41 mg/dl and from -2.96 to +0.3 kg, respectively, in patients with T2D enrolled in the GetGoal clinical program (a program of clinical trials that established the efficacy and safety profile of lixisenatide 20 μg once/day across patients with T2D with differing background therapies). Lixisenatide was well tolerated, demonstrating rates of symptomatic hypoglycemia of 0.8-42.9% and a very low rate of severe hypoglycemia (< 1.5%) as well as no increased risk of cardiovascular events. The most common adverse events were gastrointestinal in nature, mainly transient nausea and vomiting of mild-to-moderate severity. Lixisenatide effectively lowers Hb_A1c levels in patients with T2D through a mechanism of action complementary to that of agents that mainly target FPG, with the additional benefit of weight loss. Its once-daily administration schedule and effect on PPG levels make it an attractive option as add-on treatment to basal insulin therapy or oral antidiabetic agents.

Lixisenatide

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Changes in the Intestinal Microbiome and Alcoholic and Nonalcoholic Liver Diseases: Causes or Effects?

The prevalence of fatty liver diseases is increasing rapidly worldwide; after treatment of hepatitis C virus infection becomes more widespread, fatty liver diseases are likely to become the most prevalent liver disorders. Although fatty liver diseases are associated with alcohol, obesity, and the metabolic syndrome, their mechanisms of pathogenesis are not clear. The development and progression of fatty liver, alcoholic, and nonalcoholic liver disease (NAFLD) all appear to be influenced by the composition of the microbiota. The intestinal microbiota have been shown to affect precirrhotic and cirrhotic stages of liver diseases, which could lead to new strategies for their diagnosis, treatment, and study. We review differences and similarities in the cirrhotic and precirrhotic stages of NAFLD and alcoholic liver disease. Differences have been observed in these stages of alcohol-associated disease in patients who continue to drink compared with those who stop, with respect to the composition and function of the intestinal microbiota and intestinal integrity. NAFLD and the intestinal microbiota also differ between patients with and without diabetes. We also discuss the potential of microbial therapy for patients with NAFLD and ALD.

Sulfonamide-1,3,5-triazine–thiazoles: discovery of a novel class of antidiabetic agents via inhibition of DPP-4

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a novel class of antidiabetic drugs used for treating type 2 diabetes mellitus.

Pathophysiological mechanisms involved in non-alcoholic steatohepatitis and novel potential therapeutic targets

Non-alcoholic fatty liver disease (NAFLD) is a major health care problem and represents the hepatic expression of the metabolic syndrome. NAFLD is classified as non-alcoholic fatty liver (NAFL) or simple steatosis, and non-alcoholic steatohepatitis (NASH). NASH is characterized by the presence of steatosis and inflammation with or without fibrosis. The physiopathology of NAFL and NASH and their progression to cirrhosis involve several parallel and interrelated mechanisms, such as, insulin resistance (IR), lipotoxicity, inflammation, oxidative stress, and recently the gut-liver axis interaction has been described. Incretin-based therapies could play a role in the treatment of NAFLD. Glucagon-like peptide-1 (GLP-1) is an intestinal mucosa-derived hormone which is secreted into the bloodstream in response to nutrient ingestion; it favors glucose-stimulated insulin secretion, inhibition of postprandial glucagon secretion and delayed gastric emptying. It also promotes weight loss and is involved in lipid metabolism. Once secreted, GLP-1 is quickly degraded by dipeptidyl peptidase-4 (DPP-4). Therefore, DPP-4 inhibitors are able to extend the activity of GLP-1. Currently, GLP-1 agonists and DPP-4 inhibitors represent attractive options for the treatment of NAFLD and NASH. The modulation of lipid and glucose metabolism through nuclear receptors, such as the farsenoid X receptor, also constitutes an attractive therapeutic target. Obeticholic acid is a potent activator of the farnesoid X nuclear receptor and reduces liver fat content and fibrosis in animal models. Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid with immunomodulatory, anti-inflammatory, antiapoptotic, antioxidant and anti-fibrotic properties. UDCA can improve IR and modulate lipid metabolism through its interaction with nuclear receptors such as, TGR5, farnesoid X receptor-α, or the small heterodimeric partner. Finally, pharmacologic modulation of the gut microbiota could have a role in the therapy of NAFLD and NASH. Probiotics prevent bacterial translocation and epithelial invasion, inhibit mucosal adherence by bacteria, and stimulate host immunity. In animal models, probiotics prevent obesity, decrease transaminase levels, and improve IR and liver histology in NASH.

Evaluation of the long-term durability and glycemic control of fasting plasma glucose and glycosylated hemoglobin for pioglitazone in Japanese patients with type 2 diabetes

BACKGROUND

This study applied a pharmacodynamic model-based approach to evaluate the long-term durability and glycemic control of pioglitazone in comparison with other oral glucose-lowering drugs in Japanese type 2 diabetes mellitus (T2DM) patients.

SUBJECTS AND METHODS

Japanese T2DM patients were enrolled in a prospective, randomized, open-label, blinded-end point study and received pioglitazone with or without other oral glucose-lowering drugs (excluding another thiazolidinedione [TZD]) (n=293) or oral glucose-lowering drugs excluding TZD (n=294). Treatment was adjusted to achieve glycosylated hemoglobin (HbA1c) <6.9%, and samples for fasting plasma glucose (FPG) and HbA1c were collected over 2.5-4 years. A simultaneous cascading indirect response model structure was applied to describe the time course of FPG and HbA1c. HbA1c levels were described using both an FPG-dependent and an FPG-independent function. To account for titration, drug effects for both treatment groups were implemented using a time-dependent Emax model.

RESULTS

Pioglitazone was superior in both time to maximum effect and the magnitude of reduction achieved in FPG and HbA1c. A greater reduction in median FPG (-21 mg/dL vs. -9 mg/dL) was observed with pioglitazone (P<0.05). Maximum drug effect for FPG was predicted to occur earlier (11 months) for pioglitazone than for the control group (14 months). The simulated additional reduction in FPG and HbA1c achieved with pioglitazone was predicted to be maintained beyond the currently observed study duration.

CONCLUSIONS

Pioglitazone was found to result in improved glycemic control and durability compared with control treatment. This model-based approach enabled the quantification of differences in FPG and HbA1c for both treatment groups and simulation to evaluate longer-term durability on FPG and HbA1c.

Effects of glucagon-like peptide-1 receptor agonists on non-alcoholic fatty liver disease and inflammation

Glucagon-like peptide1 (GLP-1) is secreted from Langerhans cells in response to oral nutrient intake. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a new class of incretin-based anti-diabetic drugs. They function to stimulate insulin secretion while suppressing glucagon secretion. GLP-1-based therapies are now well established in the management of type 2 diabetes mellitus (T2DM), and recent literature has suggested potential applications of these drugs in the treatment of obesity and for protection against cardiovascular and neurological diseases. As we know, along with change in lifestyles, the prevalence of non-alcoholic fatty liver disease (NAFLD) in China is rising more than that of viral hepatitis and alcoholic fatty liver disease, and NAFLD has become the most common chronic liver disease in recent years. Recent studies further suggest that GLP-1RAs can reduce transaminase levels to improve NAFLD by improving blood lipid levels, cutting down the fat content to promote fat redistribution, directly decreasing fatty degeneration of the liver, reducing the degree of liver fibrosis and improving inflammation. This review shows the NAFLD-associated effects of GLP-1RAs in animal models and in patients with T2DM or obesity who are participants in clinical trials.

Optimizing nanomedicine pharmacokinetics using physiologically based pharmacokinetics modelling

The delivery of therapeutic agents is characterized by numerous challenges including poor absorption, low penetration in target tissues and non-specific dissemination in organs, leading to toxicity or poor drug exposure. Several nanomedicine strategies have emerged as an advanced approach to enhance drug delivery and improve the treatment of several diseases. Numerous processes mediate the pharmacokinetics of nanoformulations, with the absorption, distribution, metabolism and elimination (ADME) being poorly understood and often differing substantially from traditional formulations. Understanding how nanoformulation composition and physicochemical properties influence drug distribution in the human body is of central importance when developing future treatment strategies. A helpful pharmacological tool to simulate the distribution of nanoformulations is represented by physiologically based pharmacokinetics (PBPK) modelling, which integrates system data describing a population of interest with drug/nanoparticle in vitro data through a mathematical description of ADME. The application of PBPK models for nanomedicine is in its infancy and characterized by several challenges. The integration of property-distribution relationships in PBPK models may benefit nanomedicine research, giving opportunities for innovative development of nanotechnologies. PBPK modelling has the potential to improve our understanding of the mechanisms underpinning nanoformulation disposition and allow for more rapid and accurate determination of their kinetics. This review provides an overview of the current knowledge of nanomedicine distribution and the use of PBPK modelling in the characterization of nanoformulations with optimal pharmacokinetics.