Continuous subcutaneous delivery of exenatide via ITCA 650 leads to sustained glycemic control and weight loss for 48 weeks in metformin-treated subjects with type 2 diabetes

Emerging Technologies in Endocrine Drug Delivery: Innovations for Improved Patient Care

Recent advancements in drug delivery systems for endocrine disorders have significantly improved patient outcomes by addressing the limitations of traditional methods such as oral tablets and injections. These innovations include non-invasive alternatives like inhaled insulin, which provides rapid absorption and better patient compliance, and robotic pills that deliver drugs directly to specific gastrointestinal sites, enhancing absorption and reducing side effects. Wearable artificial pancreas systems have revolutionized diabetes management by integrating continuous glucose monitoring with insulin pumps to automate blood glucose control. These systems demonstrate superior glycemic control and reduce hypoglycemic events. Additionally, smart insulin pens enhance diabetes care through dose tracking and real-time data sharing, improving accuracy and adherence. Microneedle patches offer a minimally invasive method for transdermal drug delivery, effectively administering hormones and therapeutic peptides without the pain and inconvenience of injections. These patches dissolve after use, eliminating biohazardous waste. Implantable devices provide long-term, controlled release of medications, significantly improving adherence and glycemic control of patients with diabetes. Hydrogels also offer new drug delivery options.  This review examines these technologies' clinical efficacy, safety, advantages, and limitations, highlighting their potential to transform endocrine disorder management. Integrating advanced delivery systems marks a significant step towards personalized medicine, tailoring treatments to individual patient needs for better health outcomes.

Drug release profile of a novel exenatide long-term drug delivery system (OKV-119) administered to cats

Beneficial weight-loss properties of glucagon-like peptide-1 receptor agonists (GLP-1RA) in obese people, with corresponding improvements in cardiometabolic risk factors, are well established. OKV-119 is an investigational drug delivery system that is being developed for the long-term delivery of the GLP-1RA exenatide to feline patients. The purpose of this study was to evaluate the drug release characteristics of subcutaneous OKV-119 implants configured to release exenatide for 84 days. Following a 7-day acclimation period, five purpose-bred cats were implanted with OKV-119 protypes and observed for a 112-day study period. Food intake, weekly plasma exenatide concentrations and body weight were measured. Exenatide plasma concentrations were detected at the first measured timepoint (Day 7) and maintained above baseline for over 84 Days. Over the first 28 days, reduced caloric intake and a reduction in body weight were observed in four of five cats. In these cats, a body weight reduction of at least 5% was maintained throughout the 112-day study period. This study demonstrates that a single OKV-119 implant can deliver the GLP-1RA exenatide for a months long duration. Results suggest that exposure to exenatide plasma concentrations ranging from 1.5 ng/ml to 4 ng/ml are sufficient for inducing weight loss in cats.

Subcutaneous infusion of exenatide and cardiovascular outcomes in type 2 diabetes: a non-inferiority randomized controlled trial

Glucagon-like peptide 1 receptor agonists (GLP-1RAs) injected periodically have been shown to not increase and, for some members of this class, decrease the risk of cardiovascular events. The cardiovascular safety of delivering a continuous subcutaneous infusion of the GLP-1RA exenatide (ITCA 650) is unknown. Here, we randomly assigned patients with type 2 diabetes with, or at risk for, atherosclerotic cardiovascular disease (ASCVD) to receive ITCA 650 or placebo to assess cardiovascular safety in a pre-approval trial ( NCT01455896 ). The primary outcome was a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke or hospitalization for unstable angina. On the basis of 2008 guidance from the US Food and Drug Administration, a non-inferiority margin of 1.8 for the upper bound of the 95% confidence interval (CI) of the hazard ratio (HR) was used. We randomized 4,156 patients (2,075 assigned to receive ITCA 650 and 2,081 assigned to receive placebo) who were followed for a median of 16 months. The primary outcome occurred in 4.6% (95/2,075) of patients in the ITCA 650 group and 3.8% (79/2,081) of patients in the placebo group, meeting the pre-specified non-inferiority criterion (HR = 1.21, 95% CI, 0.90-1.63, P_{non-inferiority} = 0.004). Serious adverse events were similar between the two groups. Adverse events were more frequent in the ITCA 650 group (72%, 1,491/2,074) than in the placebo group (63.9%, 1,325/2,070), mainly due to an increase in gastrointestinal events and disorders while on ITCA 650. In patients with type 2 diabetes with, or at risk for, ASCVD, ITCA 650 was non-inferior to placebo. A larger and longer-duration cardiovascular outcomes trial is needed to define more precisely the cardiovascular effects of ITCA 650 in this population.

Safety, Tolerability, and Proof-Of-Concept Study of OKV-119, a Novel Exenatide Long-Term Drug Delivery System, in Healthy Cats

Background: Glucagon-like peptide-1 (GLP-1) is an incretin hormone that plays an important role in glucose homeostasis and food intake. In people, GLP-1 receptor agonists (GLP-1RAs) are commonly used for the treatment of type 2 diabetes mellitus (DM) and obesity; however, non-adherence to injectable medications is common. OKV-119 is an investigational drug delivery system intended for subdermal implantation and delivery of the GLP-1RA exenatide for up to 6 months.

Hypothesis/Objectives: Develop protocols for the subcutaneous (SC) insertion and removal of OKV-119 and to evaluate its tolerability, in vivo drug-releasing characteristics, and weight-loss effects in cats.

Animals: Two cadaveric and 19 purpose-bred cats.

Methods: In cadavers, OKV-119 insertion protocol and imaging were performed at three SC locations. The safety and tolerability of OKV-119 implants were assessed in a small (n = 4 cats) 62-day study. Weekly plasma exenatide concentrations and body weight were measured in a 42-day proof-of-concept study designed to evaluate OKV-119 prototypes implanted in cats (n = 15).

Results: In anesthetized cats, the duration of insertion and removal procedures was 1–2 min. OKV-119 was easily identified on radiographs, and well-tolerated without any apparent implant site reactions. Following implantation, exanatide plasma concentrations were observed for up to 35 days. Plasma exenatide concentrations were correlated to weight loss.

Conclusion and clinical importance: Our findings suggest that OKV-119 could be easily inserted and removed during a routine clinic visit and can be used to safely and effectively deliver exenatide. Future studies of OKV-119, configured to release exenatide for a longer extended months-long duration, are warranted to determine whether the combination of metabolic improvements and beneficial weight-loss, coupled with minimal impact on pet-owner's lifestyle, lead to improved outcomes for obese cats and feline DM patients.

Cardiovascular outcomes trials with incretin-based medications: a critical review of data available on GLP-1 receptor agonists and DPP-4 inhibitors

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors are so called "incretin-based therapies" (IBTs) that represent innovative therapeutic approaches and are commonly used in clinical practice for the treatment of type 2 diabetes mellitus (T2DM). The cardiovascular outcome trials (CVOTs) have provided useful information that has helped to shape changes in clinical practice guidelines for the management of T2DM. At the same time, the mechanisms that may explain the nonglycemic and cardiovascular (CV) benefits of these medications are still being explored. A summary of the main findings from CVOTs performed to-date with particular emphasis on various outcomes and inconsistencies observed in the trials is provided. Overall, available data is favourable to the early deployment of GLP-1RAs in clinical practice, fully in line with recommendations from international scientific guidelines, and based on their effects on glucose metabolism parameters, body weight reduction and CV outcomes. Evidence further suggest that the CV benefits of GLP-1RAs may not be a class effect, with GLP-1 analogues having a greater benefit rather than exendin-based agents.

From Animal Poisons and Venoms to Medicines: Achievements, Challenges and Perspectives in Drug Discovery

Animal poisons and venoms are comprised of different classes of molecules displaying wide-ranging pharmacological activities. This review aims to provide an in-depth view of toxin-based compounds from terrestrial and marine organisms used as diagnostic tools, experimental molecules to validate postulated therapeutic targets, drug libraries, prototypes for the design of drugs, cosmeceuticals, and therapeutic agents. However, making these molecules applicable requires extensive preclinical trials, with some applications also demanding clinical trials, in order to validate their molecular target, mechanism of action, effective dose, potential adverse effects, as well as other fundamental parameters. Here we go through the pitfalls for a toxin-based potential therapeutic drug to become eligible for clinical trials and marketing. The manuscript also presents an overview of the current picture for several molecules from different animal venoms and poisons (such as those from amphibians, cone snails, hymenopterans, scorpions, sea anemones, snakes, spiders, tetraodontiformes, bats, and shrews) that have been used in clinical trials. Advances and perspectives on the therapeutic potential of molecules from other underexploited animals, such as caterpillars and ticks, are also reported. The challenges faced during the lengthy and costly preclinical and clinical studies and how to overcome these hindrances are also discussed for that drug candidates going to the bedside. It covers most of the drugs developed using toxins, the molecules that have failed and those that are currently in clinical trials. The article presents a detailed overview of toxins that have been used as therapeutic agents, including their discovery, formulation, dosage, indications, main adverse effects, and pregnancy and breastfeeding prescription warnings. Toxins in diagnosis, as well as cosmeceuticals and atypical therapies (bee venom and leech therapies) are also reported. The level of cumulative and detailed information provided in this review may help pharmacists, physicians, biotechnologists, pharmacologists, and scientists interested in toxinology, drug discovery, and development of toxin-based products.

Impact of Glucose-Lowering Medications on Cardiovascular and Metabolic Risk in Type 2 Diabetes

Type 2 Diabetes Mellitus (T2DM) is associated with a high risk of atherosclerotic cardiovascular (CV) disease. Among the well-known pathophysiologic factors, crucial roles are played by endothelial dysfunction (caused by oxidative stress and inflammation hyperglycemia-linked), increased activity of nuclear factor kB, altered macrophage polarization, and reduced synthesis of resident endothelial progenitor cells. As consequence, a potentially rapid progression of the atherosclerotic disease with a higher propensity to unstable plaque is arguable, finally leading to significantly increased cardiovascular mortality. Main managements are focused on both prevention and early diagnosis, by targeted treatment of hyperglycemia and vascular complications. Innovative therapeutic approaches for T2DM seek to customize the antidiabetic treatment to each patient in order to optimize glucose-lowering effects, minimize hypoglycemia and adverse effects, and prevent cardiovascular events. The newer drugs (e.g., Glucagon Like Peptide-1 Receptor Agonists, GLP-1 RAs; Sodium GLucose coTransporter-2 inhibitors, SGLT2is; DiPeptidyl Peptidase-4 inhibitors, and DPP4is) impact body weight, lipid parameters, and blood pressure, as well as endothelial (dys)functions, inflammatory markers, biomarkers of both oxidative stress, and subclinical atherosclerosis. The present review summarizes the results of the main trials focused on the cardiovascular safety of these drugs from the CV standpoint.

Molecular and Materials Engineering for Delivery of Peptide Drugs to Treat Type 2 Diabetes

Type 2 diabetes is exploding globally. Despite numerous treatment options, nearly half of type 2 diabetics are unsuccessful at properly managing the disease, primarily due to a lack of patient compliance, driven by adverse side effects as well as complicated and frequent dosing schedules. Improving the delivery of type 2 diabetes drugs has the potential to increase patient compliance and thus, greatly enhance health outcomes and quality of life. This review focuses on molecular and materials engineering strategies that have been implemented to improve the delivery of peptide drugs to treat type 2 diabetes. Peptide drugs benefit from high potency and specificity but suffer from instability and short half-lives that limit their utility as therapeutics and pose a significant delivery challenge. Several approaches have been developed to improve the availability and efficacy of antidiabetic peptides and proteins in vivo. These methods are reviewed herein and include devices, which sustain the release of peptides in long term, and molecular engineering strategies, which prolong circulation time and slow the release of therapeutic peptides. By optimizing the delivery of these peptides and proteins using these approaches, long-term glucose control can be achieved in type 2 diabetes patients.

Future perspectives of the pharmacological management of diabetic dyslipidemia

INTRODUCTION

Diabetic dyslipidemia is frequent among patients with type 2 diabetes mellitus (T2DM) and is characterized by an increase in triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and small-dense (atherogenic) particles, and by a decrease in low high-density lipoprotein cholesterol (HDL-C) and apolipoprotein (Apo) A1 that are strongly related to insulin resistance. The increased flux of free fatty acids from adipose tissue to the liver aggravates hepatic insulin resistance and promotes all of aspects of the dyslipidemic state. Areas covered: Statins are the first-line agents for treatment while other lipid-lowering drugs (ezetimibe, fibrate and proprotein convertase subtilisin/kexin type 9) or novel anti-diabetic agents (dipeptidyl peptidase-4 inhibitors (DPP-4is), glucagon like peptide-1 receptor agonist (GLP-1RA), sodium/glucose cotransporter 2 inhibitors (SGLT2is)) or nutraceuticals (berberine, omega 3 fatty acid, red yeast rice) can be used alone or in combination. Expert commentary: In patients with T2DM, lipid abnormalities should be identified and treated as part of the overall diabetic treatment, in order to prevent cardiovascular disease. The choice of drugs to be used is mainly based on the lipid profile and on the characteristic lipoprotein abnormalities; the use of new drugs for the treatment of hyperglycemia and lipids alteration in these patients can improve diabetic dyslipidemia.

Mitral cells and the glucagon-like peptide 1 receptor: The sweet smell of success?

The olfactory bulb (OB) is often affected at very early stages of neurodegenerative disorders, in the so-called "prodromal" phase. In Parkinson's disease (PD), olfactory disturbances appear years before motor symptoms arise. Additionally, pathological alpha-synuclein aggregates are found in olfactory regions before spreading to other areas of the brain. Being positioned at the frontier between the brain and a potentially hostile environment, could explain the particular vulnerability of the OB. Mitral cells (MCs), the principal projecting neurons of the olfactory system, are involved in the pathogenesis and in the prion-like progression of PD. They are affected by Lewy pathology and are thought to contribute to the axonal transport of misfolded alpha-synuclein to other regions of the brain. Here, we first describe the main markers reported to distinguish MCs from other olfactory neurons. We focus on the glucagon-like peptide 1 receptor (GLP-1R), a membrane protein specifically expressed in MCs. After summarizing OB pathology, we explore the idea of targeting specifically MCs with GLP-1 or its analogues. Exenatide has shown great promise as a neuroprotective and neurorestorative agent and has been used in a clinical trial for clinical PD. Since GLP-1R activation has the ability to mitigate many facets of prodromal PD pathology, we postulate that once a robust biomarker is in place that is capable of identifying individuals in the prodromal phase of PD, homing in on GLP-1R could assist in deferring, or eradicating to a significant degree, the clinical manifestation of this debilitating human disorder.

No Guts, No Loss: Toward the Ideal Treatment for Obesity in the Twenty-First Century

Over the last century, our knowledge of the processes which control appetite and weight regulation has developed significantly. The understanding of where gut hormones fit into the control of energy homeostasis in addition to the rapid advancement of pharmacotherapeutics has paved the way for the development of novel gut hormone analogs to target weight loss. Currently, bariatric surgery remains the most efficacious treatment for obesity. The emergence of gut hormone analogs may provide a useful non-surgical addition to the armamentarium in treating obesity. Simply targeting single gut hormone pathways may be insufficiently efficacious, and combination/multiple-agonist approaches may be necessary to obtain the results required for clear clinical impact.

Glucagon-like Peptide-1 Receptor Agonists: A Class Update for Treating Type 2 Diabetes

Current management options for treating type 2 diabetes are diverse. Many different classes of antidiabetes therapies are used in clinic, and several new candidates are in late-phase clinical trial. This therapeutic abundance is a windfall for patients because it facilitates individualized patient care. Evidence-based positioning of these agents is challenging, however, requiring comprehensive and balanced familiarity with each drug class. In this review, I provide a clinical update of glucagon-like peptide-1 receptor agonists (GLP-1RAs), a class of incretin-based, injectable antidiabetes therapies which improve fasting and postprandial blood glucose control through glucose-dependent pancreatic islet cell hormone secretion without significant risks for hypoglycemia. Chronic use of GLP-1RAs also promotes body weight loss through stimulation of GLP-1 receptors localized in hypothalamic satiety centres that regulate appetite, resulting in reduced caloric intake. Since 2005, when GLP-1RAs first received regulatory approval for type 2 diabetes, this class has expanded to include long-acting, once-weekly GLP-1RAs. Recent cardiovascular outcome trials demonstrate that long-term use of GLP-1RAs (liraglutide and semaglutide) reduce cardiovascular and renal complications of diabetes. Illustrating that GLP-1RAs are favourable in high-risk patients with type 2 diabetes. This review provides a clinical appraisal of the GLP-1RA class, highlighting intraclass similarities and differences, summarizing the clinical development of incretin-based diabetes therapies and focusing on currently approved GLP-1RAs. The review also discusses the implications of structural differences between GLP-1RA molecules and comments on the risks and benefits associated with GLP-1RAs and their positioning in treating type 2 diabetes.

Glucagon-like peptide 1 in health and disease

In healthy individuals, the incretin hormone glucagon-like peptide 1 (GLP1) potentiates insulin release and suppresses glucagon secretion in response to the ingestion of nutrients. GLP1 also delays gastric emptying and increases satiety. In patients with type 2 diabetes mellitus (T2DM), supraphysiological doses of GLP1 normalize the endogenous insulin response during a hyperglycaemic clamp. Owing to the short plasma half-life of native GLP1, several GLP1 receptor agonists (GLP1RAs) with longer half-lives have been developed for the treatment of T2DM. These compounds vary in chemical structure, pharmacokinetics and size, which results in different clinical effects on hyperglycaemia and body weight loss; these variations might also explain the difference in cardiovascular effect observed in large-scale cardiovascular outcome trials, in which certain GLP1RAs were shown to have a positive effect on cardiovascular outcomes. Owing to their metabolic effects, GLP1RAs are also considered for the treatment of several other lifestyle-induced conditions, such as obesity, prediabetes and liver disease. This Review provides insights into the physiology of GLP1 and its involvement in the pathophysiology of T2DM and an overview of the currently available and emerging GLP1RAs. Furthermore, we review the results from the currently available large-scale cardiovascular outcome trials and the use of GLP1RAs for other indications.

Long acting systemic HIV pre-exposure prophylaxis: an examination of the field

Oral pre-exposure prophylaxis for the prevention of HIV-1 transmission (HIV PrEP) has been widely successful as demonstrated by a number of clinical trials. However, studies have also demonstrated the need for patients to tightly adhere to oral dosing regimens in order to maintain protective plasma and tissue concentrations. This is especially true for women, who experience less forgiveness from dose skipping than men in clinical trials of HIV PrEP. There is increasing interest in long-acting (LA), user-independent forms of HIV PrEP that could overcome this adherence challenge. These technologies have taken multiple forms including LA injectables and implantables. Phase III efficacy trials are ongoing for a LA injectable candidate for HIV PrEP. This review will focus on the design considerations for both LA injectable and implantable platforms for HIV PrEP. Additionally, we have summarized the existing LA technologies currently in clinical and pre-clinical studies for HIV PrEP as well as other technologies that have been applied to HIV PrEP and contraceptives. Our discussion will focus on the potential application of these technologies in low resource areas, and their use in global women's health.

The Clinical Impact of GLP-1 Receptor Agonists in Type 2 Diabetes: Focus on the Long-Acting Analogs

GLP-1 receptor agonists (GLP-1 RAs), introduced for clinical use in 2005, have excellent potency in reducing HbA_1c and mean glucose, improving fasting plasma glucose, inducing weight loss or protecting against the weight gain associated with insulin therapy, reducing appetite, and delaying gastric emptying. Two of these medications, liraglutide and semaglutide, appear to have cardioprotective effects as reflected in cardiovascular outcomes studies. The GLP-1 RAs are associated with gastrointestinal side effects that tend to diminish over time. They have very low risk of hypoglycemia unless used in conjunction with insulin or insulin secretagogues. Two coformulations of GLP-1 RAs together with long-acting basal insulin are available for daily use. The original GLP-1 RA, exenatide, requires twice-daily injections; two short-acting analogs are given once daily. Three currently available long-acting GLP-1 RAs are injected once weekly, providing greater convenience and potentially improving patient adherence. Semaglutide appears to be the most effective in terms of HbA_1c reduction and weight loss. GLP-1 RAs can be combined with all classes of antihyperglycemic agents except DPP-4 inhibitors. Current studies are exploring the use of an implantable osmotic pump for long-term administration of a rapid acting analog (exenatide), an oral preparation of semaglutide, benefits for management of obesity and nonalcoholic steatohepatitis, and mechanisms of cardioprotective effects.

Treatment of type 2 diabetes: future approaches

INTRODUCTION OR BACKGROUND

Type 2 diabetes, which accounts for ~90% of all diabetes, is a heterogeneous and progressive disease with a variety of causative and potentiating factors. The hyperglycaemia of type 2 diabetes is often inadequately controlled, hence the need for a wider selection of glucose-lowering treatments.

SOURCES OF DATA

Medline, PubMed, Web of Science and Google Scholar.

AREAS OF AGREEMENT

Early, effective and sustained control of blood glucose defers the onset and reduces the severity of microvascular and neuropathic complications of type 2 diabetes and helps to reduce the risk of cardiovascular (CV) complications.

AREAS OF CONTROVERSY

Newer glucose-lowering agents require extensive long-term studies to confirm CV safety. The positioning of newer agents within therapeutic algorithms varies.

GROWING POINTS

In addition to their glucose-lowering efficacy, some new glucose-lowering agents may act independently to reduce CV and renal complications.

AREAS TIMELY FOR DEVELOPING RESEARCH

Studies of potential new glucose-lowering agents offer the opportunity to safely improve glycaemic control with prolonged efficacy and greater opportunity for therapeutic individualisation.

GLP-1 receptor agonists and reduction of cardiometabolic risk: Potential underlying mechanisms

Type 2 diabetes mellitus (T2DM) is a metabolic condition with an elevated impact on cardiovascular (CV) risk. The innovative therapeutic approaches for T2DM - incretin-based therapies (IBTs), including glucagon-like peptide 1 (GLP-1) receptor agonists, have become popular and more widely used in recent years. The available scientific data from clinical studies and clinical practice highlights their beyond glucose-lowering effects, which is achieved without any increase in hypoglycaemia. The former effects include reduction in body weight, lipids, blood pressure, inflammatory markers, oxidative stress, endothelial dysfunction, and subclinical atherosclerosis, thus reducing and potentially preventing CV events. In fact, the introduction of IBTs is one of the key moments in the history of diabetes research and treatment. Such therapeutic strategies allow customization of antidiabetic treatment to each patient's need and therefore obtain better metabolic control with reduced CV risk. The aim of the present paper is to provide a comprehensive overview of the effects of GLP-1RA on various cardiometabolic markers and overall CV risk, with particular attention on recent CV outcome studies and potential mechanisms. In particular, the effects of liraglutide on formation and progression of atherosclerotic plaque and mechanisms explaining its cardioprotective effects are highlighted.

Battle of GLP-1 delivery technologies

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) belong to an important therapeutic class for treatment of type 2 diabetes. Six GLP-1 RAs, each utilizing a unique drug delivery strategy, are now approved by the Food and Drug Administration (FDA) and additional, novel GLP-1 RAs are still under development, making for a crowded marketplace and fierce competition among the manufacturers of these products. As rapid elimination is a major challenge for clinical application of GLP-1 RAs, various half-life extension strategies have been successfully employed including sequential modification, attachment of fatty-acid to peptide, fusion with human serum albumin, fusion with the fragment crystallizable (Fc) region of a monoclonal antibody, sustained drug delivery systems, and PEGylation. In this review, we discuss the scientific rationale of the various half-life extension strategies used for GLP-1 RA development. By analyzing and comparing different approved GLP-1 RAs and those in development, we focus on assessing how half-life extending strategies impact the pharmacokinetics, pharmacodynamics, safety, patient usability and ultimately, the commercial success of GLP-1 RA products. We also anticipate future GLP-1 RA development trends. Since similar drug delivery strategies are also applied for developing other therapeutic peptides, we expect this case study of GLP-1 RAs will provide generalizable concepts for the rational design of therapeutic peptides products with extended duration of action.

Effects of glucagon-like peptide-1 receptor agonists on cardiovascular risk factors: A narrative review of head-to-head comparisons

Cardiovascular (CV) disease is the leading cause of death and morbidity in patients with type 2 diabetes. Five CV risk factors (blood pressure, resting heart rate, body weight, cholesterol levels and blood glucose) are monitored routinely as safety and efficacy endpoints in randomized clinical trials for diabetes therapies. To determine if different glucagon-like peptide-1 receptor agonists (GLP-1RAs) had varying effects on these CV risk factors, we reviewed 16 head-to-head trials directly comparing GLP-1RAs that included at least one of the five factors. Few trials reported statistical differences between GLP-1RAs in terms of systolic blood pressure (SBP), body weight and total cholesterol. Liraglutide increased heart rate vs its comparators in three separate trials. All GLP-1RAs reduced glycated haemoglobin (HbA1c), but exenatide twice daily and lixisenatide had statistically smaller effects compared with other GLP-1RAs. These descriptive data indicate that individual GLP-1RAs affect CV risk factors differently, potentially because of their individual pharmacokinetics and/or size. Short-acting GLP-1RAs appeared to result in smaller changes in SBP and total cholesterol compared with continuous-acting treatments, while large GLP-1RAs had a reduced effect on body weight compared with small GLP-1RAs. For glycaemic control, short-acting GLP-1RAs had a greater impact on postprandial glucose levels vs continuous-acting GLP-1RAs, but for fasting plasma glucose levels and HbA1c, continuous-acting treatments had the greater effect. No differentiating trends were obvious in heart rate data. These diverse actions of GLP-1RAs on CV risk factors should aid individualized patient treatment.

Clinical Impact of ITCA 650, a Novel Drug-Device GLP-1 Receptor Agonist, in Uncontrolled Type 2 Diabetes and Very High Baseline HbA1c: The FREEDOM-1 HBL (High Baseline) Study

OBJECTIVE

ITCA 650 is a subdermal osmotic mini-pump that continuously delivers exenatide subcutaneously for 3-6 months. The efficacy, safety, and tolerability of ITCA 650 added to diet and exercise alone or combined with metformin, sulfonylurea, or thiazolidinedione monotherapy or a combination of these drugs was evaluated in poorly controlled patients with type 2 diabetes (T2D) who were ineligible for participation in a placebo-controlled study (FREEDOM-1) because of severe hyperglycemia (HbA_1c >10% [86 mmol/mol]).

RESEARCH DESIGN AND METHODS

This 39-week, open-label, phase 3 trial enrolled patients aged 18-80 years with HbA_1c >10% to ≤12% (86-108 mmol/mol) and BMI 25-45 kg/m². Patients received ITCA 650 20 μg/day for 13 weeks, then 60 μg/day for 26 weeks. The primary end point was change in HbA_1c at week 39.

RESULTS

Sixty patients were enrolled. At baseline, mean HbA_1c was 10.8% (94.7 mmol/mol) and mean (± SD) duration of diabetes was 8.6 (± 5.3) years. At week 39, there was a mean reduction in HbA_1c of -2.8% (-30.3 mmol/mol; P < 0.001 vs. baseline) and in body weight of -1.2 kg (P = 0.105), and 25% of patients achieved HbA_1c <7% (53 mmol/mol). A reduction in HbA_1c of ≥1% (≥10.9 mmol/mol) occurred in 90% of patients. The most common adverse events were nausea, vomiting, diarrhea, and headache. Gastrointestinal adverse events were generally transient and subsided over time; only 4 patients (6.7%) discontinued for gastrointestinal events.

CONCLUSIONS

Treatment with ITCA 650, the first injection-free glucagon-like peptide 1 receptor agonist, resulted in significant improvements in glycemic control in poorly controlled long-standing T2D patients with a high baseline HbA_1c >10%.

Treatment satisfaction with ITCA 650, a novel drug-device delivering continuous exenatide, versus twice-daily injections of exenatide in type 2 diabetics using metformin

AIMS

To evaluate treatment satisfaction in patients with type 2 diabetes (T2D) not adequately controlled by metformin, randomized to ITCA 650 (continuous exenatide in osmotic mini-pump) vs twice-daily exenatide injections (Ex-BID).

MATERIALS AND METHODS

The Diabetes Medication Satisfaction Tool (DM-SAT) was administered and assessments were made at baseline, Week 8 and Week 20 during a 24-week open-label phase 2 trial. In Stage I (Weeks 1-12), 155 patients, comprising the ITT population, were randomized to 3 groups: ITCA 650 20 μg/day, ITCA 650 40 μg/day and Ex-BID 10 μg BID. In Stage II (Weeks 13-24), ITCA 650 groups were re-randomized to either remain on the Stage I dose or receive a higher dose. Patients treated with Ex-BID were randomized to 40 or 60 μg/day ITCA 650.

RESULTS

Patients using ITCA 650 reported significant increases in overall treatment satisfaction by Week 8 vs those using Ex-BID (P < .01), despite similar clinical efficacy and overall rates of nausea. During Stage II, further improvement in HbA1c and weight were seen after 3-fold dose escalation of ITCA 650 and treatment satisfaction was maintained. When patients using Ex-BID were switched to ITCA 650, treatment satisfaction increased and reached levels similar to those initially treated with ITCA 650. Neither GI side effects of nausea and/or vomiting, nor the procedure to sub-dermally place ITCA 650, significantly impacted treatment satisfaction scores.

CONCLUSION

ITCA 650 added to metformin for patients with T2D, and for those who switched to ITCA 650 from Ex-BID, meaningfully improved glucose control and significantly increased overall treatment satisfaction.

Glucose-lowering therapies in type 2 diabetes: Opportunities and challenges for peptides

This overview considers the opportunities and challenges that face the use of gluco-regulatory peptides to treat type 2 diabetes. New insulin analogues and formulations are being developed with pharmacokinetic properties to speed-up or prolong transfer from a subcutaneous injection site to the target tissues, or to selectively favour effects on the liver. Alternative routes of insulin administration continue to attract attention, and advances in the integration of glucose monitoring with insulin pump devices are improving miniaturised 'closed loop' artificial pancreas systems. Proof of concept has been established for non-cellular glucose-responsive insulin delivery ('smart insulins') to release insulin from implants or circulating depots in proportion to circulating glucose. The many peptides involved in blood glucose control offer diverse therapeutic opportunities. Exploitation of multiple selected receptor targets using constructs of hybrid and chimeric peptides, especially those based on glucagon and gastrointestinal hormones, has gained much credence from initial preclinical studies. Peptide templates identified from comparative endocrine studies have also provided valuable insights in this respect and indicated novel approaches to address associated conditions such as obesity and infections at the same time. Nevertheless, there are many challenges to the use of therapeutic peptides that impose on every step in the complex pathway from design and testing through to making a fully characterised therapeutic product, and optimising administration, tissue targeting and degradation. Stability of peptides and immunological uncertainties of novel structures require particular consideration as well as the need to avoid over-reduction of blood glucose into hypoglycaemia.

Efficacy and Safety of ITCA 650, a Novel Drug-Device GLP-1 Receptor Agonist, in Type 2 Diabetes Uncontrolled With Oral Antidiabetes Drugs: The FREEDOM-1 Trial

OBJECTIVE

ITCA 650 (exenatide in osmotic mini-pump) continuously delivers exenatide subcutaneously for 3-6 months. Two doses of ITCA 650 were compared with placebo in patients with uncontrolled type 2 diabetes.

RESEARCH DESIGN AND METHODS

This 39-week, phase 3, double-blind, placebo-controlled trial randomized 460 patients aged 18-80 years with glycated hemoglobin (HbA_1c) 7.5-10% [58-86 mmol/mol] 1:1:1 to placebo, ITCA 650 40 μg/day, or ITCA 650 60 μg/day. Primary end point was change in HbA_1c at 39 weeks.

RESULTS

Least squares (LS) mean change from baseline HbA_1c was -1.1% [-12.2 mmol/mol] and -1.2% [-13.2 mmol/mol] for ITCA 650 40 and 60 μg/day, respectively (P < 0.001 vs. placebo -0.1% [-1.3 mmol/mol]). In a prespecified analysis, greater HbA_1c reductions occurred in patients not receiving sulfonylureas (SUs) versus those receiving SUs (-1.7% vs. -1.2% [-18.6 and -13.1 mmol/mol]). At week 39, HbA_1c <7% [53 mmol/mol] was attained in 37%, 44%, and 9% of ITCA 650 40 μg/day, ITCA 650 60 μg/day, and placebo groups, respectively (P < 0.001 each dose vs. placebo). LS mean change from baseline body weight was -2.3 kg and -3.0 kg for ITCA 650 40 and 60 μg/day, respectively (P ≤ 0.015 vs. placebo -1.0 kg). Nausea was the most common adverse event (AE) and subsided over time. Discontinuation for gastrointestinal AEs occurred in 7.2% with ITCA and 1.3% with placebo. Most AEs associated with procedures to place and remove ITCA 650 were mild and transient.

CONCLUSIONS

ITCA 650 significantly reduced HbA_1c and weight compared with placebo and was well tolerated in patients with uncontrolled type 2 diabetes on oral antidiabetes medications.

Clinically advancing and promising polymer-based therapeutics

In this review article, we will examine the history of polymers and their evolution from provisional World War II materials to medical therapeutics. To provide a comprehensive look at the current state of polymer-based therapeutics, we will classify technologies according to targeted areas of interest, including central nervous system-based and intraocular-, gastrointestinal-, cardiovascular-, dermal-, reproductive-, skeletal-, and neoplastic-based systems. Within each of these areas, we will consider several examples of novel, clinically available polymer-based therapeutics; in addition, this review will also include a discussion of developing therapies, ranging from the in vivo to clinical trial stage, for each targeted area of treatment. Finally, we will emphasize areas of patient care in need of more effective, accessible, and targeted treatment approaches where polymer-based therapeutics may offer potential solutions.

Fc-modified exenatide-loaded nanoparticles for oral delivery to improve hypoglycemic effects in mice

To improve the oral efficiency of exenatide, we prepared polyethylene glycol-poly(lactic-co-glycolic acid) (PEG-PLGA) NPs modified with Fc (NPs-Fc) for exenatide oral delivery. Exenatide was encapsulated into the NPs by the w/o/w emulsion-solvent evaporation method. The particle size of the NPs-Fc was approximately 30 nm larger than that of the unmodified NPs with polydispersity indices in a narrow range (PDIs; PDI < 0.3) as detected by DLS, and the highest encapsulation efficiency of exenatide in the NPs was greater than 80%. Fc-conjugated NPs permeated Caco-2 cells faster and to a greater extent compared to unmodified NPs, as verified by CLSM and flow cytometry. Hypoglycemic effect studies demonstrated that oral administration of exenatide-loaded PEG-PLGA NPs modified by an Fc group extended the hypoglycemic effects compared with s.c. injection of the exenatide solution. Fluorescence-labeled NPs were used to investigate the effects of Fc targeting, and the results demonstrated that the NPs-Fc stayed in the gastrointestinal tract for a longer time in comparison with the unmodified NPs, as shown by the whole-body fluorescence images and fluorescence images of the dissected organs detected by in vivo imaging in live mice. Therefore, Fc-targeted nano-delivery systems show great promise for oral peptide/protein drug delivery.

Pharmacokinetic drug evaluation of exenatide for the treatment of type 2 diabetes

INTRODUCTION

Glucagon-like peptide-1 (GLP-1) receptor analogs are a group of therapeutic agents which mimic endogenous GLP-1, exerting their effect by the stimulation of the GLP-1 receptor with a wide distribution. Its activation increases insulin releasing dependent on blood glucose levels, suppression of glucagon secretion and a reduction of hepatic glucose output. It delays gastric emptying and increases satiety. Exenatide is the synthetic version of exendin-4, a natural peptide with similar properties to human GLP-1. There are two pharmaceutical forms, for subcutaneous injection: twice daily and once weekly. Clinical practice guidelines recommend them because of a high efficacy reducing hyperglycemia, low risk of hypoglycemia and a significative weight loss effect. Gastrointestinal adverse events are the most common beside injection site-related. Their cost is the main limitation to use. Areas covered: We review the recent literature investigating the pharmacokinetics and pharmacodynamics and efficacy-safety studies of exenatide twice daily and once weekly in type 2 diabetes Expert opinion: GLP-1 receptor analogs are now positioned as an effective and safe drug for the treatment of type 2 diabetes. Exenatide significally reduces HbA1c and fasting plasma glucose. Additionally, it produces moderate weight loss and decreases blood pressure. One weekly formulation may improve compliance while cost is still a limitation. EXSCEL trial has shown that, despite cardiovascular safety, exenatide do not exhibits cardiovascular benefits.

Pharmacological management of type 2 diabetes: what's new in 2017?

INTRODUCTION

Novelties in the management of type 2 diabetes are dominated by the commercialisation of new glucose-lowering agents, which offer alternatives to older antidiabetic medications, and by the publication of several prospective placebo-controlled outcome trials, which demonstrated not only cardiovascular safety but also cardiovascular and renal protection with some new medications. Areas covered: Updates regarding the use of glucose-lowering agents are discussed from a clinical point of view. Some new viewpoints concern older antidiabetic agents such as metformin, sulfonylureas and glitazones whose benefit-risk balance has been revisited, especially in high risk patients. The recent data regarding DPP-4 inhibitors (gliptins) focused on the safety profile of this pharmacological class, including in patients with impaired renal function. The highlight concerns the cardiovascular (and renal) protection by some GLP-1 receptor agonists (liraglutide, semaglutide) and SGLT2 inhibitors (empagliflozin, canagliflozin) in patients with high cardiovascular risk. Finally, efficacy and safety of new combinations and advances in insulin therapy will be briefly discussed. Expert commentary: The recent data from randomized controlled trials, meta-analyses and observational real-life studies should trigger a revision of the algorithm for the treatment of hyperglycemia in type 2 diabetes, especially in patients with high cardiovascular and/or renal risk.

A Hydrogel-Microsphere Drug Delivery System That Supports Once-Monthly Administration of a GLP-1 Receptor Agonist

We have developed a chemically controlled very long-acting delivery system to support once-monthly administration of a peptidic GLP-1R agonist. Initially, the prototypical GLP-1R agonist exenatide was covalently attached to hydrogel microspheres by a self-cleaving β-eliminative linker; after subcutaneous injection in rats, the peptide was slowly released into the systemic circulation. However, the short serum exenatide half-life suggested its degradation in the subcutaneous depot. We found that exenatide undergoes deamidation at Asn²⁸ with an in vitro and in vivo half-life of approximately 2 weeks. The [Gln²⁸]exenatide variant and exenatide showed indistinguishable GLP-1R agonist activities as well as pharmacokinetic and pharmacodynamic effects in rodents; however, unlike exenatide, [Gln²⁸]exenatide is stable for long periods. Two different hydrogel-[Gln²⁸]exenatide conjugates were prepared using β-eliminative linkers with different cleavage rates. After subcutaneous injection in rodents, the serum half-lives for the released [Gln²⁸]exenatide from the two conjugates were about 2 weeks and one month. Two monthly injections of the latter in the Zucker diabetic fatty rat showed pharmacodynamic effects indistinguishable from two months of continuously infused exenatide. Pharmacokinetic simulations indicate that the delivery system should serve well as a once-monthly GLP-1R agonist for treatment of type 2 diabetes in humans.

The Current State of Peptide Drug Discovery: Back to the Future?

Over the past decade, peptide drug discovery has experienced a revival of interest and scientific momentum, as the pharmaceutical industry has come to appreciate the role that peptide therapeutics can play in addressing unmet medical needs and how this class of compounds can be an excellent complement or even preferable alternative to small molecule and biological therapeutics. In this Perspective, we give a concise description of the recent progress in peptide drug discovery in a holistic manner, highlighting enabling technological advances affecting nearly every aspect of this field: from lead discovery, to synthesis and optimization, to peptide drug delivery. An emphasis is placed on describing research efforts to overcome the inherent weaknesses of peptide drugs, in particular their poor pharmacokinetic properties, and how these efforts have been critical to the discovery, design, and subsequent development of novel therapeutics.

Is It Time to Change the Type 2 Diabetes Treatment Paradigm? Yes! GLP-1 RAs Should Replace Metformin in the Type 2 Diabetes Algorithm

Most treatment guidelines, including those from the American Diabetes Association/European Association for the Study of Diabetes and the International Diabetes Federation, suggest metformin be used as the first-line therapy after diet and exercise. This recommendation is based on the considerable body of evidence that has accumulated over the last 30 years, but it is also supported on clinical grounds based on metformin's affordability and tolerability. As such, metformin is the most commonly used oral antihyperglycemic agent in the U.S. However, based on the release of newer agents over the recent past, some have suggested that the modern approach to disease management should be based upon identification of its etiology and correcting the underlying biological disturbances. That is, we should use interventions that normalize or at least ameliorate the recognized derangements in physiology that drive the clinical manifestation of disease, in this circumstance, hyperglycemia. Thus, it is argued that therapeutic interventions that target glycemia but do not correct the underlying pathogenic disturbances are unlikely to result in a sustained benefit on the disease process. In our field, there is an evolving debate regarding the suggested first step in diabetes management and a call for a new paradigm. Given the current controversy, we provide a Point-Counterpoint debate on this issue. In the point narrative below that precedes the counterpoint narrative, Drs. Abdul-Ghani and DeFronzo provide their argument that a treatment approach for type 2 diabetes based upon correcting the underlying pathophysiological abnormalities responsible for the development of hyperglycemia provides the best therapeutic strategy. Such an approach requires a change in the recommendation for first-line therapy from metformin to a GLP-1 receptor agonist. In the counterpoint narrative that follows Drs. Abdul-Ghani and DeFronzo's contribution, Dr. Inzucchi argues that, based on the medical community's extensive experience and the drug's demonstrated efficacy, safety, low cost, and cardiovascular benefits, metformin should remain the "foundation therapy" for all patients with type 2 diabetes, barring contraindications.-William T. CefaluChief Scientific, Medical & Mission Officer, American Diabetes Association.

A Narrative Review of Potential Future Antidiabetic Drugs: Should We Expect More?

Prevalence of diabetes mellitus, a chronic metabolic disease characterized by hyperglycemia, is growing worldwide. The majority of the cases belong to type 2 diabetes mellitus (T2DM). Globally, India ranks second in terms of diabetes prevalence among adults. Currently available classes of therapeutic agents are used alone or in combinations but seldom achieve treatment targets. Diverse pathophysiology and the need of therapeutic agents with more favourable pharmacokinetic-pharmacodynamics profile make newer drug discoveries in the field of T2DM essential. A large number of molecules, some with novel mechanisms, are in pipeline. The essence of this review is to track and discuss these potential agents, based on their developmental stages, especially those in phase 3 or phase 2. Unique molecules are being developed for existing drug classes like insulins, DPP-4 inhibitors, GLP-1 analogues; and under newer classes like dual/pan PPAR agonists, dual SGLT1/SGLT2 inhibitors, glimins, anti-inflammatory agents, glucokinase activators, G-protein coupled receptor agonists, hybrid peptide agonists, apical sodium-dependent bile acid transporter (ASBT) inhibitors, glucagon receptor antagonists etc. The heterogeneous clinical presentation and therapeutic outcomes in phenotypically similar patients is a clue to think beyond the standard treatment strategy.

WITHDRAWN: Glucagon-like Peptide-1 Receptor Agonists: A Class Update for Treating Type 2 Diabetes

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.jcjd.2017.02.003. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Exenatide: pharmacokinetics, clinical use, and future directions

INTRODUCTION

The first-in-class glucagon-like peptide-1 receptor agonist (GLP-1RA) exenatide, which was initially approved in 2005, is available in twice-daily (BID) and once-weekly (QW) formulations. Clinical trial data suggest both formulations are effective and safe for patients with type 2 diabetes (T2D), both as monotherapy and as part of combination therapy. Since exenatide was approved, several other GLP-1RAs have become available for clinical use. Areas covered: Many ongoing clinical trials involving exenatide BID and exenatide QW are investigating new indications (exenatide BID) and new end points and combination therapies (exenatide QW). This review provides an overview of the delivery and pharmacokinetics of both formulations of exenatide, reviews existing data in T2D, and summarizes ongoing investigations. Expert opinion: Exenatide BID and QW have substantial clinical benefits. Comparisons with other GLP-1RAs demonstrate some differences in efficacy and safety profiles that make assessment of benefit:risk ratios complex. Head-to-head comparisons of QW GLP-1RA formulations may assist in the ranking of GLP-1RAs according to efficacy and safety. Results on the impact of exenatide QW on cardiovascular outcomes are eagerly awaited. The potential clinical utility of exenatide BID in other indications will clarify whether exenatide holds clinical promise in diagnoses other than T2D.

Improving drug-like properties of insulin and GLP-1 via molecule design and formulation and improving diabetes management with device & drug delivery

There is an increased incidence of diabetes worldwide. The discovery of insulin revolutionized the management of diabetes, the revelation of glucagon-like peptide-1 (GLP-1) and introduction of GLP-1 receptor agonists to clinical practice was another breakthrough. Continued translational research resulted in better understanding of diabetes, which, in combination with cutting-edge biology, chemistry, and pharmaceutical tools, have allowed for the development of safer, more effective and convenient insulins and GLP-1. Advances in self-administration of insulin and GLP-1 receptor agonist therapies with use of drug-device combination products have further improved the outcomes of diabetes management and quality of life for diabetic patients. The synergies of insulin and GLP-1 receptor agonist actions have led to development of devices that can deliver both molecules simultaneously. New chimeric GLP-1-incretins and insulin-GLP-1-incretin molecules are also being developed. The objective of this review is to summarize molecular designs to improve the drug-like properties of insulin and GLP-1 and to highlight the continued advancement of drug-device combination products to improve diabetes management.

Efficacy and Safety of Multiple Doses of Exenatide Once-Monthly Suspension in Patients With Type 2 Diabetes: A Phase II Randomized Clinical Trial

OBJECTIVE

This study investigated the efficacy and safety of multiple exenatide once-monthly suspension (QMS) doses of exenatide-containing microspheres in Miglyol referenced against the clinical dose of exenatide once-weekly (QW) microspheres in aqueous solution.

RESEARCH DESIGN AND METHODS

In this phase II, randomized, controlled, single-blind study, 121 adults (∼30/arm) with type 2 diabetes and HbA1c 7.1-11.0% (54-97 mmol/mol) were randomized 1:1:1:1 to subcutaneous exenatide QW 2 mg (self-administered) or exenatide QMS 5, 8, or 11 mg (caregiver-administered) for 20 weeks. The primary end point was change in HbA1c.

RESULTS

At baseline, mean age was 50 years, HbA1c was 8.5% (69 mmol/mol), fasting plasma glucose (FPG) was 184 mg/dL, and body weight was 98 kg. At week 20, mean ± SD HbA1c reductions were -1.54% ± 1.26% with exenatide QW and -1.29% ± 1.07%, -1.31% ± 1.66%, and -1.45% ± 0.93% with exenatide QMS 5, 8, and 11 mg, respectively (evaluable population: n = 110). There were no significant differences in HbA1c reductions among the exenatide QMS doses. FPG reductions were -34 ± 48 mg/dL with exenatide QW and -25 ± 43, -30 ± 52, and -49 ± 49 mg/dL with exenatide QMS 5, 8, and 11 mg, respectively. Weight decreased with all treatments. For exenatide QMS, nausea (16.7-23.3%) and headache (16.7-26.7%) were the most common adverse events. No major or minor hypoglycemia occurred.

CONCLUSIONS

All doses of exenatide QMS resulted in efficacy and tolerability profiles consistent with exenatide QW. These results combined with pharmacokinetic and pharmacodynamic modeling could inform dose selection for further development.

Peptide-based GLP-1/glucagon co-agonists: A double-edged sword to combat diabesity

Diabesity is a new term for obesity-dependent diabetes, which is also associated with cardiovascular and other comorbidities with rising epidemic. Traditional treatments (sulfonylureas and thiazolidinediones) of diabetes are associated with weight gain, except metformin. Newer agents such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and Sodium glucose co-transporter 2 inhibitors (SGLT2i) are causing a modest weight reduction, whereas dipeptidyl peptidase-4 inhibitors (DPP-4i) are weight neutral. Oxyntomodulin, a native GLP-1/glucagon receptor agonist produced a superior weight loss and antihyperglycemic effects in obese mice and humans. Recent findings with synthetic dual GLP-1/glucagon receptor agonists have shown a good weight loss and antihyperglycemic profile in diet-induced obese (DIO) mice. Targeting combinations of GLP-1 receptor and glucagon receptor simultaneously with a single peptide may be the better strategy to achieve marked weight loss and considerable glycemic control in diabesity. Cardiovascular safety is very important with new antidiabetic agents due to rosiglitazone controversy. Current on-going clinical trials will clarify the cardiovascular effects of incretin-based therapies in near future. Based on current knowledge and rapid progress in the field, there is a strong possibility that the GLP-1/glucagon receptor co-agonists will likely be the new therapeutic treatment for diabesity for decades to come.

Investigational glucagon-like peptide-1 agonists for the treatment of obesity

INTRODUCTION

Obesity is a worldwide problem predisposing to type 2 diabetes mellitus (T2DM), hypertension, cardiovascular disease, cancer and other comorbidities. Lifestyle modification is the first line intervention but adjunctive pharmacotherapy is often required. The GLP-1 receptor agonists (GLP-1RAs) were developed primarily for T2DM and they also reduce body weight. Liraglutide was approved for the treatment of obesity and other GLP-1RAs are likely to be suitable for this indication.

AREAS COVERED

This review describes the GLP-1RAs that have been approved for the treatment of T2DM as potential candidates for the treatment of obesity and the new agents currently under development which may have advantages in patient adherence.

EXPERT OPINION

The GLP-1RAs offer a welcome addition to obesity pharmacotherapy. They appear to be free of serious adverse effects although uncertainty remains about possible risks of pancreatitis and neoplasms. However, they have frequent gastrointestinal side effects, particularly nausea, which limits their tolerability. Cardiovascular outcome studies in T2DM support their use and this is likely to increase in both T2DM and obesity. Other GLP-1RAs which can be given by subcutaneous injection once weekly or less frequently or by oral administration would have advantages especially if nausea is less frequent than with liraglutide.

Future glucose-lowering drugs for type 2 diabetes

The multivariable and progressive natural history of type 2 diabetes limits the effectiveness of available glucose-lowering drugs. Constraints imposed by comorbidities (notably cardiovascular disease and renal impairment) and the need to avoid hypoglycaemia, weight gain, and drug interactions further complicate the treatment process. These challenges have prompted the development of new formulations and delivery methods for existing drugs alongside research into novel pharmacological entities. Advances in incretin-based therapies include a miniature implantable osmotic pump to give continuous delivery of a glucagon-like peptide-1 receptor agonist for 6-12 months and once-weekly tablets of dipeptidyl peptidase-4 inhibitors. Hybrid molecules that combine the properties of selected incretins and other peptides are at early stages of development, and proof of concept has been shown for small non-peptide molecules to activate glucagon-like peptide-1 receptors. Additional sodium-glucose co-transporter inhibitors are progressing in development as well as possible new insulin-releasing biological agents and small-molecule inhibitors of glucagon action. Adiponectin receptor agonists, selective peroxisome proliferator-activated receptor modulators, cellular glucocorticoid inhibitors, and analogues of fibroblast growth factor 21 are being considered as potential new approaches to glucose lowering. Compounds that can enhance insulin receptor and post-receptor signalling cascades or directly promote selected pathways of glucose metabolism have suggested opportunities for future treatments. However, pharmacological interventions that are able to restore normal β-cell function and β-cell mass, normalise insulin action, and fully correct glucose homoeostasis are a distant vision.