The Discovery and Development of Liraglutide and Semaglutide

Glucagon-Like Peptide-1 Receptor Agonists and Brain Vascular Function

Prevention of cardiovascular events and regression of atherosclerotic changes are the primary aims of preventive cardiovascular medicine. Arterial thrombosis is caused by endothelial dysfunction, which disrupts vascular haemostasis. Glucagon-like peptide 1 (GLP-1) receptor agonists have been initially used as glucose lowering agents, but over time have been used for other indications due to their cardiorenal benefit, as well as their benefit in the regression of atherosclerosis process. The aim of this paper is to present the benefits of GLP-1 receptor agonists in the prevention of atherosclerotic changes, in the preservation of brain vascular function, and to show the possible role in the treatment of neurodegenerative diseases.

Potential kidney protection with liraglutide and semaglutide: Exploratory mediation analysis

AIMS

To investigate whether effects on chronic kidney disease risk factors could explain the apparent reduction in kidney outcomes (composite of macroalbuminuria, doubling of serum creatinine, renal replacement therapy, or renal death), primarily driven by changes in albuminuria, after treatment with the glucagon-like peptide-1 receptor agonists (GLP-1RAs) liraglutide and semaglutide in patients with type 2 diabetes in the LEADER and SUSTAIN 6 trials.

MATERIALS AND METHODS

We evaluated the mediation effect of glycated haemoglobin (HbA1c), systolic blood pressure (BP), and body weight on the kidney effects of GLP-1RAs. Diastolic BP, haemoglobin, heart rate, low-density lipoprotein and total cholesterol, and white blood cell count were also investigated. The mediation effect was estimated by the novel Vansteelandt statistical method. Subgroups with estimated glomerular filtration rate (eGFR) <60 and ≥60 mL/min/1.73 m² were examined in LEADER.

RESULTS

We observed that HbA1c mediated 25% (95% confidence interval [CI] -7.1; 67.3) and 26% (95% CI noncalculable), and systolic BP 9% (95% CI 2.8; 22.7) and 22% (95% CI noncalculable) of kidney effects of GLP-1RAs in LEADER and SUSTAIN 6, respectively. Small or no mediation was observed for the other parameters; for example, body weight mediated 9% (95% CI -7.9; 35.5) in the former and did not mediate effects in the latter study. Mediation by HbA1c was greater in patients with eGFR ≥60 mL/min/1.73 m² (57%) versus those with eGFR <60 mL/min/1.73 m² (no mediation).

CONCLUSIONS

Our results suggest that HbA1c and systolic BP may moderately mediate kidney benefits of liraglutide and semaglutide, with all other variables having a small to no effect. Potential kidney benefits may be driven by other mediators or potentially by direct mechanisms.

Lipophilic Conjugates of Drugs: A Tool to Improve Drug Pharmacokinetic and Therapeutic Profiles

Lipophilic conjugates (LCs) of small molecule drugs have been used widely in clinical and pre-clinical studies to achieve a number of pharmacokinetic and therapeutic benefits. For example, lipophilic derivatives of drugs are employed in several long acting injectable products to provide sustained drug exposure for hormone replacement therapy and to treat conditions such as neuropsychiatric diseases. LCs can also be used to modulate drug metabolism, and to enhance drug permeation across membranes, either by increasing lipophilicity to enhance passive diffusion or by increasing protein-mediated active transport. Furthermore, such conjugation strategies have been employed to promote drug association with endogenous macromolecular carriers (e.g. albumin and lipoproteins), and this in turn results in altered drug distribution and pharmacokinetic profiles, where the changes can be 'general' (e.g. prolonged plasma half-life) or 'specific' (e.g. enhanced delivery to specific tissues in parallel with the macromolecular carriers). Another utility of LCs is to enhance the encapsulation of drugs within engineered nanoscale drug delivery systems, in order to best take advantage of the targeting and pharmacokinetic benefits of nanomedicines. The current review provides a summary of the mechanisms by which lipophilic conjugates, including in combination with delivery vehicles, can be used to control drug delivery, distribution and therapeutic profiles. The article is structured into sections which highlight a specific benefit of LCs and then demonstrate this benefit with case studies. The review attempts to provide a toolbox to assist researchers to design and optimise drug candidates, including consideration of drug-formulation compatibility.

Oral semaglutide in the management of type 2 DM: Clinical status and comparative analysis

BACKGROUND

In the incretin system, Glucagon-like peptide-1 (GLP-1) is a hormone that inhibits the release of glucagon and regulates glucose-dependent insulin secretion. In type 2 diabetes, correcting the impaired incretin system using GLP-1 agonist is a well-defined therapeutic strategy.

OBJECTIVES

This review article aims to discuss the mechanism of action, key regulatory events, clinical trials for glycaemic control and comparative analysis of semaglutide with the second-line antidiabetic drugs.

DESCRIPTION

Semaglutide is a glucagon-like peptide 1 (GLP 1) receptor agonist with enhanced glycaemic control in diabetes patients. In 2019, USFDA approved the first oral GLP-1 receptor agonist, semaglutide to be administered as a once-daily tablet. Further, recent studies highlight the ability of semaglutide to improve the glycaemic control in obese patients with a reduction in body weight. Still, in clinical practice, in type 2 DM treatment paradigm the impact of oral semaglutide remains unidentified. This review article discusses the mechanism of action, pharmacodynamics, key regulatory events, and clinical trials regarding glycaemic control.

CONCLUSION

The review highlights the comparative analysis of semaglutide with the existing second-line drugs for the management of type 2 diabetes mellitus by stressing on its benefits and adverse events.

Partial agonism improves the anti-hyperglycaemic efficacy of an oxyntomodulin-derived GLP-1R/GCGR co-agonist

OBJECTIVE

Glucagon-like peptide-1 and glucagon receptor (GLP-1R/GCGR) co-agonism can maximise weight loss and improve glycaemic control in type 2 diabetes and obesity. In this study, we investigated the cellular and metabolic effects of modulating the balance between G protein and β-arrestin-2 recruitment at GLP-1R and GCGR using oxyntomodulin (OXM)-derived co-agonists. This strategy has been previously shown to improve the duration of action of GLP-1R mono-agonists by reducing target desensitisation and downregulation.

METHODS

Dipeptidyl dipeptidase-4 (DPP-4)-resistant OXM analogues were generated and assessed for a variety of cellular readouts. Molecular dynamic simulations were used to gain insights into the molecular interactions involved. In vivo studies were performed in mice to identify the effects on glucose homeostasis and weight loss.

RESULTS

Ligand-specific reductions in β-arrestin-2 recruitment were associated with slower GLP-1R internalisation and prolonged glucose-lowering action in vivo. The putative benefits of GCGR agonism were retained, with equivalent weight loss compared to the GLP-1R mono-agonist liraglutide despite a lesser degree of food intake suppression. The compounds tested showed only a minor degree of biased agonism between G protein and β-arrestin-2 recruitment at both receptors and were best classified as partial agonists for the two pathways measured.

CONCLUSIONS

Diminishing β-arrestin-2 recruitment may be an effective way to increase the therapeutic efficacy of GLP-1R/GCGR co-agonists. These benefits can be achieved by partial rather than biased agonism.

New Incretin Combination Treatments under Investigation in Obesity and Metabolism: A Systematic Review

The worldwide upward trend in obesity in adults and the increased incidence of overweight children suggests that the future risk of obesity-related illnesses will be increased. The existing anti-obesity drugs act either in the central nervous system (CNS) or in the peripheral tissues, controlling the appetite and metabolism. However, weight regain is a common homeostatic response; current anti-obesity medications show limited effectiveness in achieving long-term weight loss maintenance; in addition to being linked to various side effects. Combined anti-obesity medications (per os or injectable) target more than one of the molecular pathways involved in weight regulation, as well as structures in the CNS. In this systematic review, we conducted a search of PubMed and The ClinicalTrials.gov up to February 2021. We summarized the Food and Drug Administration (FDA)-approved medications, and we focused on the combined pharmacological treatments, related to the incretin hormones, currently in a clinical trial phase. We also assessed the mechanism of action and therapeutic utility of these novel hybrid peptides and potential interactions with other regulatory hormones that may have beneficial effects on obesity. As we improve our understanding of the pathophysiology of obesity, we hope to identify more novel treatment strategies.

Purification of Modified Therapeutic Proteins Available on the Market: An Analysis of Chromatography-Based Strategies

Proteins, which have inherent biorecognition properties, have long been used as therapeutic agents for the treatment of a wide variety of clinical indications. Protein modification through covalent attachment to different moieties improves the therapeutic's pharmacokinetic properties, affinity, stability, confers protection against proteolytic degradation, and increases circulation half-life. Nowadays, several modified therapeutic proteins, including PEGylated, Fc-fused, lipidated, albumin-fused, and glycosylated proteins have obtained regulatory approval for commercialization. During its manufacturing, the purification steps of the therapeutic agent are decisive to ensure the quality, effectiveness, potency, and safety of the final product. Due to the robustness, selectivity, and high resolution of chromatographic methods, these are recognized as the gold standard in the downstream processing of therapeutic proteins. Moreover, depending on the modification strategy, the protein will suffer different physicochemical changes, which must be considered to define a purification approach. This review aims to deeply analyze the purification methods employed for modified therapeutic proteins that are currently available on the market, to understand why the selected strategies were successful. Emphasis is placed on chromatographic methods since they govern the purification processes within the pharmaceutical industry. Furthermore, to discuss how the modification type strongly influences the purification strategy, the purification processes of three different modified versions of coagulation factor IX are contrasted.

Obesity and Cardiomyopathy

While much has been written about the syndrome of diabetic cardiomyopathy, clinicians and research scientists are now beginning to realize that an entirely unique syndrome exists, albeit with several commonalities to the diabetic syndrome, that being obesity cardiomyopathy. This syndrome develops independent of such comorbidities as hypertension, myocardial infarction and coronary artery disease; and it is characterized by specific alterations in adipose tissue function, inflammation and metabolism. Recent insights into the etiology of the syndrome and its consequences have focused on the roles played by altered intracellular calcium homeostasis, reactive oxygen species, and mitochondrial dysfunction. A timely and comprehensive review by Ren, Wu, Wang, Sowers and Zhang (1) identifies unique mechanisms underlying this syndrome, its relationship to heart failure and the recently identified incidence of COVID-19-related cardiovascular mortality. Importantly, the review concludes by advancing recommendations for novel approaches to the clinical management of this dangerous form of cardiomyopathy.

Treatment of Metabolic Syndrome in Children

Although metabolic syndrome (MetS) in children and adolescents is a frequently discussed topic in the literature, uniform guidelines on its definition and treatment are still lacking. Insulin resistance, central obesity, dyslipidaemia, and hypertension are commonly considered the main components of MetS. The first recommended approach to all these pathological conditions in children and adolescents is lifestyle intervention (diet and physical exercise); however, in some selected cases, a pharmacological or surgical treatment might prove useful for the prevention of metabolic and cardiovascular complications. The aim of this review is to present the more recent evidence about the treatment of the major components of MetS in children and adolescents, focussing on the current recommendations concerning lifestyle changes, available drugs, and bariatric surgery.

Molecular and pharmacological characterization of insulin icodec: a new basal insulin analog designed for once-weekly dosing

INTRODUCTION

Insulin icodec is a novel, long-acting insulin analog designed to cover basal insulin requirements with once-weekly subcutaneous administration. Here we describe the molecular engineering and the biological and pharmacological properties of insulin icodec.

RESEARCH DESIGN AND METHODS

A number of in vitro assays measuring receptor binding, intracellular signaling as well as cellular metabolic and mitogenic responses were used to characterize the biological properties of insulin icodec. To evaluate the pharmacological properties of insulin icodec in individuals with type 2 diabetes, a randomized, double-blind, double-dummy, active-controlled, multiple-dose, dose escalation trial was conducted.

RESULTS

The long half-life of insulin icodec was achieved by introducing modifications to the insulin molecule aiming to obtain a safe, albumin-bound circulating depot of insulin icodec, providing protracted insulin action and clearance. Addition of a C20 fatty diacid-containing side chain imparts strong, reversible albumin binding, while three amino acid substitutions (A14E, B16H and B25H) provide molecular stability and contribute to attenuating insulin receptor (IR) binding and clearance, further prolonging the half-life. In vitro cell-based studies showed that insulin icodec activates the same dose-dependent IR-mediated signaling and metabolic responses as native human insulin (HI). The affinity of insulin icodec for the insulin-like growth factor-1 receptor was proportionately lower than its binding to the IR, and the in vitro mitogenic effect of insulin icodec in various human cells was low relative to HI. The clinical pharmacology trial in people with type 2 diabetes showed that insulin icodec was well tolerated and has pharmacokinetic/pharmacodynamic properties that are suited for once-weekly dosing, with a mean half-life of 196 hours and close to even distribution of glucose-lowering effect over the entire dosing interval of 1 week.

CONCLUSIONS

The molecular modifications introduced into insulin icodec provide a novel basal insulin with biological and pharmacokinetic/pharmacodynamic properties suitable for once-weekly dosing.

TRIAL REGISTRATION NUMBER

NCT02964104.

Contemporary Classification of Glucagon-Like Peptide 1 Receptor Agonists (GLP1RAs)

This communication provides a contemporary classification of glucagon-like peptide 1 receptor agonists (GLP1RAs) based on indication, route, and frequency of administration, which could support a person-centric approach to treatment choice. It includes all recently developed GLP1RAs as well as those in advanced stages of clinical study. Keeping pace with current trends in pharmacology and metabolic medicine, it attempts to bring clarity and simplicity to a complex spread of information.

Brain GLP-1 and the regulation of food intake: GLP-1 action in the brain and its implications for GLP-1 receptor agonists in obesity treatment

This review considers the similarities and differences between the physiological systems regulated by gut-derived and neuronally produced glucagon-like peptide 1 (GLP-1). It addresses the questions of whether peripheral and central GLP-1 sources constitute separate, linked or redundant systems and whether the brain GLP-1 system consists of disparate sections or is a homogenous entity. This review also explores the implications of the answers to these questions for the use of GLP-1 receptor agonists as anti-obesity drugs.

The effects of liraglutide and dapagliflozin on cardiac function and structure in a multi-hit mouse model of heart failure with preserved ejection fraction

AIMS

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial disease that constitutes several distinct phenotypes, including a common cardiometabolic phenotype with obesity and type 2 diabetes mellitus. Treatment options for HFpEF are limited, and development of novel therapeutics is hindered by the paucity of suitable preclinical HFpEF models that recapitulate the complexity of human HFpEF. Metabolic drugs, like glucagon-like peptide receptor agonist (GLP-1 RA) and sodium-glucose co-transporter 2 inhibitors (SGLT2i), have emerged as promising drugs to restore metabolic perturbations and may have value in the treatment of the cardiometabolic HFpEF phenotype. We aimed to develop a multifactorial HFpEF mouse model that closely resembles the cardiometabolic HFpEF phenotype, and evaluated the GLP-1 RA liraglutide (Lira) and the SGLT2i dapagliflozin (Dapa).

METHODS AND RESULTS

Aged (18-22 months old) female C57BL/6J mice were fed a standardized chow (CTRL) or high-fat diet (HFD) for 12 weeks. After 8 weeks HFD, angiotensin II (ANGII), was administered for 4 weeks via osmotic mini pumps. HFD + ANGII resulted in a cardiometabolic HFpEF phenotype, including obesity, impaired glucose handling, and metabolic dysregulation with inflammation. The multiple hit resulted in typical clinical HFpEF features, including cardiac hypertrophy and fibrosis with preserved fractional shortening but with impaired myocardial deformation, atrial enlargement, lung congestion, and elevated blood pressures. Treatment with Lira attenuated the cardiometabolic dysregulation and improved cardiac function, with reduced cardiac hypertrophy, less myocardial fibrosis, and attenuation of atrial weight, natriuretic peptide levels, and lung congestion. Dapa treatment improved glucose handling, but had mild effects on the HFpEF phenotype.

CONCLUSIONS

We developed a mouse model that recapitulates the human HFpEF disease, providing a novel opportunity to study disease pathogenesis and the development of enhanced therapeutic approaches. We furthermore show that attenuation of cardiometabolic dysregulation may represent a novel therapeutic target for the treatment of HFpEF.

Development of Cagrilintide, a Long-Acting Amylin Analogue

A hallmark of the pancreatic hormone amylin is its high propensity toward the formation of amyloid fibrils, which makes it a challenging drug design effort. The amylin analogue pramlintide is commercially available for diabetes treatment as an adjunct to insulin therapy but requires three daily injections due to its short half-life. We report here the development of the stable, lipidated long-acting amylin analogue cagrilintide (23) and some of the structure-activity efforts that led to the selection of this analogue for clinical development with obesity as an indication. Cagrilintide is currently in clinical trial and has induced significant weight loss when dosed alone or in combination with the GLP-1 analogue semaglutide.

Safety of Semaglutide

The glucagon-like peptide-1 receptor agonist (GLP-1RA) semaglutide is the most recently approved agent of this drug class, and the only GLP-1RA currently available as both subcutaneous and oral formulation. While GLP-1RAs effectively improve glycemic control and cause weight loss, potential safety concerns have arisen over the years. For semaglutide, such concerns have been addressed in the extensive phase 3 registration trials including cardiovascular outcome trials for both subcutaneous (SUSTAIN: Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes) and oral (PIONEER: Peptide InnOvatioN for the Early diabEtes tReatment) semaglutide and are being studied in further trials and registries, including real world data studies. In the current review we discuss the occurrence of adverse events associated with semaglutide focusing on hypoglycemia, gastrointestinal side effects, pancreatic safety (pancreatitis and pancreatic cancer), thyroid cancer, gallbladder events, cardiovascular aspects, acute kidney injury, diabetic retinopathy (DRP) complications and injection-site and allergic reactions and where available, we highlight potential underlying mechanisms. Furthermore, we discuss whether effects are specific for semaglutide or a class effect. We conclude that semaglutide induces mostly mild-to-moderate and transient gastrointestinal disturbances and increases the risk of biliary disease (cholelithiasis). No unexpected safety issues have arisen to date, and the established safety profile for semaglutide is similar to that of other GLP-1RAs where definitive conclusions for pancreatic and thyroid cancer cannot be drawn at this point due to low incidence of these conditions. Due to its potent glucose-lowering effect, patients at risk for deterioration of existing DRP should be carefully monitored if treated with semaglutide, particularly if also treated with insulin. Given the beneficial metabolic and cardiovascular actions of semaglutide, and the low risk for severe adverse events, semaglutide has an overall favorable risk/benefit profile for patient with type 2 diabetes.

Patient initiation and maintenance of GLP-1 RAs for treatment of obesity

Introduction: Healthcare providers (HCPs) see many patients with obesity-related complications and are therefore well placed to help treat obesity itself. However, limited collated information exists to help HCPs with the practical use of anti-obesity medications (AOMs). We focus on the initiation and maintenance of a glucagon-like peptide-1 receptor agonist (GLP-1 RA) for weight management, liraglutide 3.0 mg. Literature search was conducted between 25-28 November 2019 on PubMed and ClinicalTrials.gov.Areas covered: Clinical trial and real-world data describing weight-loss efficacy, cardiometabolic risk factors, incidence of adverse events (AEs), and persistence are presented to assist HCPs with patient discussions. Practical considerations to overcome barriers to optimal use are provided, equipping HCPs with the information required to aid with adherence to and persistence with AOMs. The use of other GLP-1- RA therapies in obesity is discussed in light of the recent US Food and Drug Administration approval of semaglutide 2.4 mg for weight management.Expert opinion: Liraglutide 3.0 mg provides benefits regarding weight loss and improvements in cardiometabolic risk factors. Promising areas of future research in the field of obesity include dual receptor agonists and the combination of glucagon-like peptide-1 receptor agonists with other molecules.

Re-Assessing PK/PD Issues for Oral Protein and Peptide Delivery

Due to a lack of safe and effective oral delivery strategies for most protein and peptide therapeutics, pharmaceutical drug developers have focused on parenteral routes to administer these agents. Recent advances in delivery technologies have now shown clinical validation for a few of these biopharmaceuticals following oral administration. While these initial opportunities have provided more than just a glimmer of hope within the industry, there are important aspects of oral biopharmaceutical delivery that do not completely align with pharmacokinetic (PK) parameters and pharmacodynamics (PD) outcomes that have been learned from parenteral administrations. This commentary examines some of these issues with the goal of presenting a rationale for re-assessing methods, models, and success criteria to better measure oral protein or peptide delivery outcomes related to PK/PD events.

PEG-based thermosensitive and biodegradable hydrogels

Injectable thermosensitive hydrogels are free-flowing polymer solutions at low or room temperature, making them easy to encapsulate the therapeutic payload or cells via simply mixing. Upon injection into the body, in situ forming hydrogels triggered by body temperature can act as drug-releasing reservoirs or cell-growing scaffolds. Finally, the hydrogels are eliminated from the administration sites after they accomplish their missions as depots or scaffolds. This review outlines the recent progress of poly(ethylene glycol) (PEG)-based biodegradable thermosensitive hydrogels, especially those composed of PEG-polyester copolymers, PEG-polypeptide copolymers and poly(organophosphazene)s. The material design, performance regulation, thermogelation and degradation mechanisms, and corresponding applications in the biomedical field are summarized and discussed. A perspective on the future thermosensitive hydrogels is also highlighted. STATEMENT OF SIGNIFICANCE: Thermosensitive hydrogels undergoing reversible sol-to-gel phase transitions in response to temperature variations are a class of promising biomaterials that can serve as minimally invasive injectable systems for various biomedical applications. Hydrophilic PEG is a main component in the design and fabrication of thermoresponsive hydrogels due to its excellent biocompatibility. By incorporating hydrophobic segments, such as polyesters and polypeptides, into PEG-based systems, biodegradable and thermosensitive hydrogels with adjustable properties in vitro and in vivo have been developed and have recently become a research hotspot of biomaterials. The summary and discussion on molecular design, performance regulation, thermogelation and degradation mechanisms, and biomedical applications of PEG-based thermosensitive hydrogels may offer a demonstration of blueprint for designing new thermogelling systems and expanding their application scope.

Fluid intake, what's dopamine got to do with it?

Maintaining fluid balance is critical for life. The central components that control fluid intake are only partly understood. This contribution to the collection of papers highlighting work by members of the Society for the Study of Ingestive Behavior focuses on the role that dopamine has on fluid intake and describes the roles that various bioregulators can have on thirst and sodium appetite by influencing dopamine systems in the brain. The goal of the review is to highlight areas in need of more research and to propose a framework to guide that research. We hope that this framework will inspire researchers in the field to investigate these interesting questions in order to form a more complete understanding of how fluid intake is controlled.

Recent advances in proteolytic stability for peptide, protein, and antibody drug discovery

Introduction: To discover and develop a peptide, protein, or antibody into a drug requires overcoming multiple challenges to obtain desired properties. Proteolytic stability is one of the challenges and deserves a focused investigation.Areas covered: This review concentrates on improving proteolytic stability by engineering the amino acids around the cleavage sites of a liable peptide, protein, or antibody. Peptidases are discussed on three levels including all peptidases in databases, mixtures based on organ and tissue types, and individual peptidases. The technique to identify cleavage sites is spotlighted on mass spectrometry-based approaches such as MALDI-TOF and LC-MS. For sequence engineering, the replacements that have been commonly applied with a higher chance of success are highlighted at the beginning, while the rarely used and more complicated replacements are discussed later. Although a one-size-fits-all approach does not exist to apply to different projects, this review provides a 3-step strategy for effectively and efficiently conducting the proteolytic stability experiments to achieve the eventual goal of improving the stability by engineering the molecule itself.Expert opinion: Improving the proteolytic stability is a spiraling up process sequenced by testing and engineering. There are many ways to engineer amino acids, but the choice must consider the cost and properties affected by the changes of the amino acids.

Hypothalamic GPCR Signaling Pathways in Cardiometabolic Control

Obesity is commonly associated with sympathetic overdrive, which is one of the major risk factors for the development of cardiovascular diseases, such as hypertension and heart failure. Over the past few decades, there has been a growing understanding of molecular mechanisms underlying obesity development with central origin; however, the relative contribution of these molecular changes to the regulation of cardiovascular function remains vague. A variety of G-protein coupled receptors (GPCRs) and their downstream signaling pathways activated in distinct hypothalamic neurons by different metabolic hormones, neuropeptides and monoamine neurotransmitters are crucial not only for the regulation of appetite and metabolic homeostasis but also for the sympathetic control of cardiovascular function. In this review, we will highlight the main GPCRs and associated hypothalamic nuclei that are important for both metabolic homeostasis and cardiovascular function. The potential downstream molecular mediators of these GPCRs will also be discussed.

Commemorating insulin's centennial: engineering insulin pharmacology towards physiology

The life-saving discovery of insulin in Toronto in 1921 is one of the most impactful achievements in medical history, at the time being hailed as a miracle treatment for diabetes. The insulin molecule itself, however, is poorly amenable as a pharmacological intervention, and the formidable challenge of optimizing insulin therapy has been ongoing for a century. We review early academic insights into insulin structure and its relation to self-association and receptor binding, as well as recombinant biotechnology, which have all been seminal for drug design. Recent developments have focused on combining genetic and chemical engineering with pharmaceutical optimization to generate ultra-rapid and ultra-long-acting, tissue-selective, or orally delivered insulin analogs. We further discuss these developments and propose that future scientific efforts in molecular engineering include realizing the dream of glucose-responsive insulin delivery.

Therapeutic Peptides Targeting PPI in Clinical Development: Overview, Mechanism of Action and Perspectives

Targeting protein-protein interactions (PPIs) has been recently recognized as an emerging therapeutic approach for several diseases. Up today, more than half a million PPI dysregulations have been found to be involved in pathological events. The dynamic nature of these processes and the involvement of large protein surfaces discouraged anyway the scientific community in considering them promising therapeutic targets. More recently peptide drugs received renewed attention since drug discovery has offered a broad range of structural diverse sequences, moving from traditionally endogenous peptides to sequences possessing improved pharmaceutical profiles. About 70 peptides are currently on the marked but several others are in clinical development. In this review we want to report the update on these novel APIs, focusing our attention on the molecules in clinical development, representing the direct consequence of the drug discovery process of the last 10 years. The comprehensive collection will be classified in function of the structural characteristics (native, analogous, heterologous) and on the basis of the therapeutic targets. The mechanism of interference on PPI will also be reported to offer useful information for novel peptide design.

A Pharmacological and Clinical Overview of Oral Semaglutide for the Treatment of Type 2 Diabetes

Oral semaglutide (Rybelsus®) is a glucagon-like peptide-1 (GLP-1) receptor agonist (GLP-1RA) with 94% homology to human GLP-1. It is the first GLP-1RA developed for oral administration, and it comprises a co-formulation of the peptide semaglutide with the absorption enhancer sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, which overcomes the challenges of peptide absorption in the acidic conditions of the stomach. Oral semaglutide is indicated for use as an add-on combination therapy (with other glucose-lowering agents, including insulin) or as a monotherapy (in patients who are intolerant to metformin) for type 2 diabetes when diet and exercise do not provide adequate glycemic control. In an extensive phase III clinical program including patients from across the disease spectrum, treatment with oral semaglutide resulted in effective glycemic control, reductions in body weight, and decreases in systolic blood pressure when used as monotherapy or in combination with other glucose-lowering therapies. Studies showed that oral semaglutide was well tolerated, with a safety profile consistent with the GLP-1RA drug class. The risk of hypoglycemia was low, and the most common adverse events were gastrointestinal, with nausea and diarrhea generally being the most frequently reported manifestations. Cardiovascular (CV) safety was shown to be noninferior to placebo and observations suggest that the CV profile of oral semaglutide is likely to be similar to that of subcutaneous semaglutide. The evolution of the GLP-1RA class to include an oral agent could facilitate the use of these agents earlier in the diabetes treatment cascade owing to wider acceptance from patients and healthcare professionals.

Synthesis and In Vivo Evaluation of Insulin-Loaded Whey Beads as an Oral Peptide Delivery System

For many diabetics, daily, lifelong insulin injections are required to effectively manage blood glucose levels and the complications associated with the disease. This can be a burden and reduces patient quality of life. Our goal was to develop a more convenient oral delivery system that may be suitable for insulin and other peptides. Insulin was entrapped in 1.5-mm beads made from denatured whey protein isolate (dWPI) using gelation. Beads were then air-dried with fumed silica, Aerosil^®. The encapsulation efficiency was ~61% and the insulin loading was ~25 µg/mg. Dissolution in simulated gastric-, and simulated intestinal fluids (SGF, SIF) showed that ~50% of the insulin was released from beads in SGF, followed by an additional ~10% release in SIF. The omission of Aerosil^® allowed greater insulin release, suggesting that it formed a barrier on the bead surface. Circular dichroism analysis of bead-released insulin revealed an unaltered secondary structure, and insulin bioactivity was retained in HepG2 cells transfected to assess activation of the endogenous insulin receptors. Insulin-entrapped beads were found to provide partial protection against pancreatin for at least 60 min. A prototype bead construct was then synthesised using an encapsulator system and tested in vivo using a rat intestinal instillation bioassay. It was found that 50 IU/kg of entrapped insulin reduced plasma glucose levels by 55% in 60 min, similar to that induced by subcutaneously (s.c.)-administered insulin (1 IU/kg). The instilled insulin-entrapped beads produced a relative bioavailability of 2.2%. In conclusion, when optimised, dWPI-based beads may have potential as an oral peptide delivery system.

Novel formulations and drug delivery systems to administer biological solids

Recent advances in formulation sciences have expanded the previously limited design space for biological modalities, including peptide, protein, and vaccine products. At the same time, the discovery and application of new modalities, such as cellular therapies and gene therapies, have presented formidable challenges to formulation scientists. We explore these challenges and highlight the opportunities to overcome them through the development of novel formulations and drug delivery systems as biological solids. We review the current progress in both industry and academic laboratories, and we provide expert perspectives in those settings. Formulation scientists have made a tremendous effort to accommodate the needs of these novel delivery routes. These include stability-preserving formulations and dehydration processes as well as dosing regimes and dosage forms that improve patient compliance.

Old Paradoxes and New Opportunities for Appetite Control in Obesity

Human obesity is accompanied by alterations in the blood concentrations of multiple circulating appetite regulators. Paradoxically, most of the appetite-inhibitory hormones are elevated in nonsyndromic obesity, while most of the appetite stimulatory hormones are reduced, perhaps reflecting vain attempts of regulation by inefficient feedback circuitries. In this context, it is important to understand which appetite regulators exhibit a convergent rather than paradoxical behavior and hence are likely to contribute to the maintenance of the obese state. Pharmacological interventions in obesity should preferentially consist of the supplementation of deficient appetite inhibitors or the neutralization of excessive appetite stimulators. Here, we critically analyze the current literature on appetite-regulatory peptide hormones. We propose a short-list of appetite modulators that may constitute the best candidates for therapeutic interventions.

Emerging synthetic drugs for the treatment of liver cirrhosis

Introduction: The number of deaths and prevalent cases of cirrhosis are increasing worldwide, but there are no licensed antifibrotic or pro-regenerative medicines and liver transplantation is a limited resource. Cirrhosis is characterized by extreme liver fibrosis, organ dysfunction, and complications related to portal hypertension. Advances in our understanding of liver fibrosis progression and regression following successful etiological therapy betray vulnerabilities in common and disease-specific mechanisms that could be targeted pharmacologically.Area covered: This review summarizes the cellular and molecular pathogenesis of cirrhosis as a preface to discussion of the current drug development landscape. The dominant indication for global pharma R&D pipelines is cirrhosis related to nonalcoholic steatohepatitis (NASH). We searched Clinicaltrials.gov, GlobalData, Pharmaprojects and PubMed for pertinent information on emerging synthetic drugs for cirrhosis, with a focus on compounds listed in phase 2 and phase 3 trials.Expert opinion: Although cirrhosis can regress following successful etiological treatment, there are no specific antifibrotic or pro-regenerative drugs approved for this condition. Obstacles to drug development in cirrhosis include intrinsic biological factors, a heterogeneous patient population, and lack of acceptable surrogate endpoints. Nevertheless, several synthetic drugs are being evaluated in clinical trials and the NASH field is rapidly embracing a drug combination approach.

The islet's bridesmaid becomes the bride: Proglucagon-derived peptides deliver transformative therapies

The 2021 Gairdner Prize is awarded to Daniel Drucker, Joel Habener, and Jens Juul Holst for the discovery of novel peptides encoded in the proglucagon sequence and the establishment of their physiological roles. These discoveries underpinned the development of therapeutics that are now benefiting patients with type 2 diabetes and other disorders worldwide.

Obesity therapeutics: The end of the beginning

Obese non-diabetic patients receiving semaglutide, an injectable long-acting GLP-1 receptor agonist, in a large randomized placebo-controlled trial, lost and maintained ∼15% of their body weight for over a year (Wilding et al., 2021). This impressive result is likely to usher in a new era of anti-obesity drugs based on hormones that suppress food intake, largely through acting on the brain.

The gut-brain axis: Identifying new therapeutic approaches for type 2 diabetes, obesity, and related disorders

BACKGROUND

The gut-brain axis, which mediates bidirectional communication between the gastrointestinal system and central nervous system (CNS), plays a fundamental role in multiple areas of physiology including regulating appetite, metabolism, and gastrointestinal function. The biology of the gut-brain axis is central to the efficacy of glucagon-like peptide-1 (GLP-1)-based therapies, which are now leading treatments for type 2 diabetes (T2DM) and obesity. This success and research to suggest a much broader role of gut-brain circuits in physiology and disease has led to increasing interest in targeting such circuits to discover new therapeutics. However, our current knowledge of this biology is limited, largely because the scientific tools have not been available to enable a detailed mechanistic understanding of gut-brain communication.

SCOPE OF REVIEW

In this review, we provide an overview of the current understanding of how sensory information from the gastrointestinal system is communicated to the central nervous system, with an emphasis on circuits involved in regulating feeding and metabolism. We then describe how recent technologies are enabling a better understanding of this system at a molecular level and how this information is leading to novel insights into gut-brain communication. We also discuss current therapeutic approaches that leverage the gut-brain axis to treat diabetes, obesity, and related disorders and describe potential novel approaches that have been enabled by recent advances in the field.

MAJOR CONCLUSIONS

The gut-brain axis is intimately involved in regulating glucose homeostasis and appetite, and this system plays a key role in mediating the efficacy of therapeutics that have had a major impact on treating T2DM and obesity. Research into the gut-brain axis has historically largely focused on studying individual components in this system, but new technologies are now enabling a better understanding of how signals from these components are orchestrated to regulate metabolism. While this work reveals a complexity of signaling even greater than previously appreciated, new insights are already being leveraged to explore fundamentally new approaches to treating metabolic diseases.

Effect of GLP-1/GLP-1R on the Polarization of Macrophages in the Occurrence and Development of Atherosclerosis

Aims

To investigate the effect of GLP-1/GLP-1R on the polarization of macrophages in the occurrence and development of atherosclerosis.

Methods

Totally, 49 patients with coronary heart disease (CHD) and 52 cases of health control (HC) were recruited, all subjects accept coronary angiography gold standard inspection. One or more major coronary arteries (LM, LAD, LCx, and RCA) stenosis degree in 50% of patients as CHD group; the rest of the stenosis less than 50% or not seen obvious stenosis are assigned to the HC group. Flow cytometry were used to detect the percentage of (CD14+) M macrophages, (CD14+CD80+) M1 macrophages, (CD14+CD206+) M2 macrophages, and their surface GLP-1R expression differences in the two groups, using BD cytokine kit to detect the levels of IL-8, IL-1β, IL-6, IL-10, TNF, and IL-12p70.

Results

GLP-1R expression on the surface of total macrophages and M2 macrophages was different between the CHD group and the HC group (P < 0.05). There was no difference in the percentage of total, M1 or M2 macrophages (P > 0.05). Concentration of IL-8 in the HC group was higher than that in the CHD group (P < 0.05). There is no significant difference in the cytokine IL-1β, IL-6, IL-10, TNF, and IL-12p70 in the two groups (P > 0.05). After controlling for potential confounders including age, gender, smoking status (S.S.), drinking status (D.S.), HR, SBP, DBP, PP, TC, TG, HDL-C, LDL-C, GHbA1c, M, M1, M2, GLP-1R_M, GLP-1R_M1, GLP-1R_M2, IL-8, IL-1β, IL-6, IL-10, TNF, and IL-12p70 by multiple linear regression, decreasing Gensini Score was significantly associated with increased percentage of M1 macrophage.

Conclusion

GLP-1R agonist is independent of the hypoglycemic effect of T2DM and has protective effect on cardiovascular system. GLP-1R may regulate the polarization of macrophages toward M2, thus playing a protective role in the progression of coronary atherosclerosis.

A Placebo-Controlled Trial of Subcutaneous Semaglutide in Nonalcoholic Steatohepatitis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a common disease that is associated with increased morbidity and mortality, but treatment options are limited. The efficacy and safety of the glucagon-like peptide-1 receptor agonist semaglutide in patients with NASH is not known.

METHODS

We conducted a 72-week, double-blind phase 2 trial involving patients with biopsy-confirmed NASH and liver fibrosis of stage F1, F2, or F3. Patients were randomly assigned, in a 3:3:3:1:1:1 ratio, to receive once-daily subcutaneous semaglutide at a dose of 0.1, 0.2, or 0.4 mg or corresponding placebo. The primary end point was resolution of NASH with no worsening of fibrosis. The confirmatory secondary end point was an improvement of at least one fibrosis stage with no worsening of NASH. The analyses of these end points were performed only in patients with stage F2 or F3 fibrosis; other analyses were performed in all the patients.

RESULTS

In total, 320 patients (of whom 230 had stage F2 or F3 fibrosis) were randomly assigned to receive semaglutide at a dose of 0.1 mg (80 patients), 0.2 mg (78 patients), or 0.4 mg (82 patients) or to receive placebo (80 patients). The percentage of patients in whom NASH resolution was achieved with no worsening of fibrosis was 40% in the 0.1-mg group, 36% in the 0.2-mg group, 59% in the 0.4-mg group, and 17% in the placebo group (P<0.001 for semaglutide 0.4 mg vs. placebo). An improvement in fibrosis stage occurred in 43% of the patients in the 0.4-mg group and in 33% of the patients in the placebo group (P = 0.48). The mean percent weight loss was 13% in the 0.4-mg group and 1% in the placebo group. The incidence of nausea, constipation, and vomiting was higher in the 0.4-mg group than in the placebo group (nausea, 42% vs. 11%; constipation, 22% vs. 12%; and vomiting, 15% vs. 2%). Malignant neoplasms were reported in 3 patients who received semaglutide (1%) and in no patients who received placebo. Overall, neoplasms (benign, malignant, or unspecified) were reported in 15% of the patients in the semaglutide groups and in 8% in the placebo group; no pattern of occurrence in specific organs was observed.

CONCLUSIONS

This phase 2 trial involving patients with NASH showed that treatment with semaglutide resulted in a significantly higher percentage of patients with NASH resolution than placebo. However, the trial did not show a significant between-group difference in the percentage of patients with an improvement in fibrosis stage. (Funded by Novo Nordisk; ClinicalTrials.gov number, NCT02970942.).

A Non-Perturbative Molecular Grafting Strategy for Stable and Potent Therapeutic Peptide Ligands

The gut-derived incretin hormone, glucagon-like peptide-1 (GLP1), plays an important physiological role in attenuating post-prandial blood glucose excursions in part by amplifying pancreatic insulin secretion. Native GLP1 is rapidly degraded by the serine protease, dipeptidyl peptidase-4 (DPP4); however, enzyme-resistant analogues of this 30-amino-acid peptide provide an effective therapy for type 2 diabetes (T2D) and can curb obesity via complementary functions in the brain. In addition to its medical relevance, the incretin system provides a fertile arena for exploring how to better separate agonist function at cognate receptors versus susceptibility of peptides to DPP4-induced degradation. We have discovered that novel chemical decorations can make GLP1 and its analogues completely DPP4 resistant while fully preserving GLP1 receptor activity. This strategy is also applicable to other therapeutic ligands, namely, glucose-dependent insulinotropic polypeptide (GIP), glucagon, and glucagon-like peptide-2 (GLP2), targeting the secretin family of receptors. The versatility of the approach offers hundreds of active compounds based on any template that target these receptors. These observations should allow for rapid optimization of pharmacological properties and because the appendages are in a position crucial to receptor stimulation, they proffer the possibility of conferring "biased" signaling and in turn minimizing side effects.

Once-Weekly Semaglutide in Adults with Overweight or Obesity

BACKGROUND

Obesity is a global health challenge with few pharmacologic options. Whether adults with obesity can achieve weight loss with once-weekly semaglutide at a dose of 2.4 mg as an adjunct to lifestyle intervention has not been confirmed.

METHODS

In this double-blind trial, we enrolled 1961 adults with a body-mass index (the weight in kilograms divided by the square of the height in meters) of 30 or greater (≥27 in persons with ≥1 weight-related coexisting condition), who did not have diabetes, and randomly assigned them, in a 2:1 ratio, to 68 weeks of treatment with once-weekly subcutaneous semaglutide (at a dose of 2.4 mg) or placebo, plus lifestyle intervention. The coprimary end points were the percentage change in body weight and weight reduction of at least 5%. The primary estimand (a precise description of the treatment effect reflecting the objective of the clinical trial) assessed effects regardless of treatment discontinuation or rescue interventions.

RESULTS

The mean change in body weight from baseline to week 68 was -14.9% in the semaglutide group as compared with -2.4% with placebo, for an estimated treatment difference of -12.4 percentage points (95% confidence interval [CI], -13.4 to -11.5; P<0.001). More participants in the semaglutide group than in the placebo group achieved weight reductions of 5% or more (1047 participants [86.4%] vs. 182 [31.5%]), 10% or more (838 [69.1%] vs. 69 [12.0%]), and 15% or more (612 [50.5%] vs. 28 [4.9%]) at week 68 (P<0.001 for all three comparisons of odds). The change in body weight from baseline to week 68 was -15.3 kg in the semaglutide group as compared with -2.6 kg in the placebo group (estimated treatment difference, -12.7 kg; 95% CI, -13.7 to -11.7). Participants who received semaglutide had a greater improvement with respect to cardiometabolic risk factors and a greater increase in participant-reported physical functioning from baseline than those who received placebo. Nausea and diarrhea were the most common adverse events with semaglutide; they were typically transient and mild-to-moderate in severity and subsided with time. More participants in the semaglutide group than in the placebo group discontinued treatment owing to gastrointestinal events (59 [4.5%] vs. 5 [0.8%]).

CONCLUSIONS

In participants with overweight or obesity, 2.4 mg of semaglutide once weekly plus lifestyle intervention was associated with sustained, clinically relevant reduction in body weight. (Funded by Novo Nordisk; STEP 1 ClinicalTrials.gov number, NCT03548935).

Nutrient-Induced Cellular Mechanisms of Gut Hormone Secretion

The gastrointestinal tract can assess the nutrient composition of ingested food. The nutrient-sensing mechanisms in specialised epithelial cells lining the gastrointestinal tract, the enteroendocrine cells, trigger the release of gut hormones that provide important local and central feedback signals to regulate nutrient utilisation and feeding behaviour. The evidence for nutrient-stimulated secretion of two of the most studied gut hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), along with the known cellular mechanisms in enteroendocrine cells recruited by nutrients, will be the focus of this review. The mechanisms involved range from electrogenic transporters, ion channel modulation and nutrient-activated G-protein coupled receptors that converge on the release machinery controlling hormone secretion. Elucidation of these mechanisms will provide much needed insight into postprandial physiology and identify tractable dietary approaches to potentially manage nutrition and satiety by altering the secreted gut hormone profile.

Selective release of gastrointestinal hormones induced by an orally active GPR39 agonist

OBJECTIVES

Obesity is a complex disease associated with a high risk of comorbidities. Gastric bypass surgery, an invasive procedure with low patient eligibility, is currently the most effective intervention that achieves sustained weight loss. This beneficial effect is attributed to alterations in gut hormone signaling. An attractive alternative is to pharmacologically mimic the effects of bariatric surgery by targeting several gut hormonal axes. The G protein-coupled receptor 39 (GPR39) expressed in the gastrointestinal tract has been shown to mediate ghrelin signaling and control appetite, food intake, and energy homeostasis, but the broader effect on gut hormones is largely unknown. A potent and efficacious GPR39 agonist (Cpd1324) was recently discovered, but the in vivo function was not addressed. Herein we studied the efficacy of the GPR39 agonist, Cpd1324, on metabolism and gut hormone secretion.

METHODS

Body weight, food intake, and energy expenditure in GPR39 agonist-treated mice and GPR39 KO mice were studied in calorimetric cages. Plasma ghrelin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) levels were measured. Organoids generated from murine and human small intestine and mouse colon were used to study GLP-1 and PYY release. Upon GPR39 agonist administration, dynamic changes in intracellular GLP-1 content were studied via immunostaining and changes in ion transport across colonic mucosa were monitored in Ussing chambers. The G protein activation underlying GPR39-mediated selective release of gut hormones was studied using bioluminescence resonance energy transfer biosensors.

RESULTS

The GPR39 KO mice displayed a significantly increased food intake without corresponding increases in respiratory exchange ratios or energy expenditure. Oral administration of a GPR39 agonist induced an acute decrease in food intake and subsequent weight loss in high-fat diet (HFD)-fed mice without affecting their energy expenditure. The tool compound, Cpd1324, increased GLP-1 secretion in the mice as well as in mouse and human intestinal organoids, but not in GPR39 KO mouse organoids. In contrast, the GPR39 agonist had no effect on PYY or GIP secretion. Transepithelial ion transport was acutely affected by GPR39 agonism in a GLP-1- and calcitonin gene-related peptide (CGRP)-dependent manner. Analysis of Cpd1324 signaling properties showed activation of Gα_q and Gα_i/o signaling pathways in L cells, but not Gα_s signaling.

CONCLUSIONS

The GPR39 agonist described in this study can potentially be used by oral administration as a weight-lowering agent due to its stimulatory effect on GLP-1 secretion, which is most likely mediated through a unique activation of Gα subunits. Thus, GPR39 agonism may represent a novel approach to effectively treat obesity through selective modulation of gastrointestinal hormonal axes.

Synthesis, Optimization, and Biological Evaluation of Corrinated Conjugates of the GLP-1R Agonist Exendin-4

Corrination is the conjugation of a corrin ring containing molecule, such as vitamin B₁₂ (B12) or B12 biosynthetic precursor dicyanocobinamide (Cbi), to small molecules, peptides, or proteins with the goal of modifying pharmacology. Recently, a corrinated GLP-1R agonist (GLP-1RA) exendin-4 (Ex4) has been shown in vivo to have reduced penetration into the central nervous system relative to Ex4 alone, producing a glucoregulatory GLP-1RA devoid of anorexia and emesis. The study herein was designed to optimize the lead conjugate for GLP-1R agonism and binding. Two specific conjugation sites were introduced in Ex4, while also utilizing various linkers, so that it was possible to identify Cbi conjugates of Ex4 that exhibit improved binding and agonist activity at the GLP-1R. An optimized conjugate (22), comparable with Ex4, was successfully screened and subsequently assayed for insulin secretion in rat islets and in vivo in shrews for glucoregulatory and emetic behavior, relative to Ex4.

The effect of semaglutide 2.4 mg once weekly on energy intake, appetite, control of eating, and gastric emptying in adults with obesity

AIM

To investigate the effects of once-weekly subcutaneous (s.c.) semaglutide 2.4 mg on gastric emptying, appetite, and energy intake in adults with obesity.

MATERIALS AND METHODS

A double-blind, parallel-group trial was conducted in 72 adults with obesity, randomized to once-weekly s.c. semaglutide (dose-escalated to 2.4 mg) or placebo for 20 weeks. Gastric emptying was assessed using paracetamol absorption following a standardized breakfast. Participant-reported appetite ratings and Control of Eating Questionnaire (CoEQ) responses were assessed, and energy intake was measured during ad libitum lunch.

RESULTS

The area under the concentration-time curve (AUC) for paracetamol 0 to 5 hours after a standardized meal (AUC_0-5h,para ; primary endpoint) was increased by 8% (P = 0.005) with semaglutide 2.4 mg versus placebo at week 20 (non-significant when corrected for week 20 body weight; P = 0.12). No effect was seen on AUC_0-1h,para , maximum observed paracetamol concentration, or time to maximum observed paracetamol concentration. Ad libitum energy intake was 35% lower with semaglutide versus placebo (1736 versus 2676 kJ; estimated treatment difference -940 kJ; P <0.0001). Semaglutide reduced hunger and prospective food consumption, and increased fullness and satiety when compared with placebo (all P <0.02). The CoEQ indicated better control of eating and fewer/weaker food cravings with semaglutide versus placebo (P <0.05). Body weight was reduced by 9.9% with semaglutide and 0.4% with placebo. Safety was consistent with the known profile of semaglutide.

CONCLUSIONS

In adults with obesity, once-weekly s.c. semaglutide 2.4 mg suppressed appetite, improved control of eating, and reduced food cravings, ad libitum energy intake and body weight versus placebo. There was no evidence of delayed gastric emptying at week 20, assessed indirectly via paracetamol absorption.

Potential Effects of COVID-19 on Cytochrome P450-Mediated Drug Metabolism and Disposition in Infected Patients

Coronavirus Disease 2019 (COVID-19) has been a global health crisis since it was first identified in December 2019. In addition to fever, cough, headache, and shortness of breath, an intense increase in immune response-based inflammation has been the hallmark of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) virus infection. This narrative review summarizes and critiques pathophysiology of COVID-19 and its plausible effects on drug metabolism and disposition. The release of inflammatory cytokines (e.g., interleukins, tumor necrosis factor α), also known as 'cytokine storm', leads to altered molecular pathophysiology and eventually organ damage in the lung, heart, and liver. The laboratory values for various liver function tests (e.g., alanine aminotransferase, aspartate aminotransferase, total bilirubin, albumin) have indicated potential hepatocellular injury in COVID-19 patients. Since the liver is the powerhouse of protein synthesis and the primary site of cytochrome P450 (CYP)-mediated drug metabolism, even a minor change in the liver function status has the potential to affect the hepatic clearance of xenobiotics. It has now been well established that extreme increases in cytokine levels are common in COVID-19 patients, and previous studies with patients infected with non-SARS-CoV-2 virus have shown that CYP enzymes can be suppressed by an infection-related cytokine increase and inflammation. Alongside the investigational COVID-19 drugs, the patients may also be on therapeutics for comorbidities; especially epidemiological studies have indicated that individuals with hypertension, hyperglycemia, and obesity are more vulnerable to COVID-19 than the average population. This complicates the drug-disease interaction profile of the patients as both the investigational drugs (e.g., remdesivir, dexamethasone) and the agents for comorbidities can be affected by compromised CYP-mediated hepatic metabolism. Overall, it is imperative that healthcare professionals pay attention to the COVID-19 and CYP-driven drug metabolism interactions with the goal to adjust the dose or discontinue the affected drugs as appropriate.

Harnessing molecular recognition for localized drug delivery

A grand challenge in drug delivery is providing the right dose, at the right anatomic location, for the right duration of time to maximize therapeutic efficacy while minimizing off-target toxicity and other deleterious side-effects. Two general modalities are receiving broad attention for localized drug delivery. In the first, referred to as "targeted accumulation", drugs or drug carriers are engineered to have targeting moieties that promote their accumulation at a specific tissue site from circulation. In the second, referred to as "local anchoring", drugs or drug carriers are inserted directly into the tissue site of interest where they persist for a specified duration of time. This review surveys recent advances in harnessing molecular recognition between proteins, peptides, nucleic acids, lipids, and carbohydrates to mediate targeted accumulation and local anchoring of drugs and drug carriers.

Obstetrician-Gynecologists' Strategies for Patient Initiation and Maintenance of Antiobesity Treatment with Glucagon-Like Peptide-1 Receptor Agonists

Obesity is a chronic disease affecting women at higher rates than men. In an obstetrics and gynecology setting, frequently encountered obesity-related complications are polycystic ovary syndrome, fertility and pregnancy complications, and increased risk of breast and gynecological cancers. Obstetrician-gynecologists (OBGYNs) are uniquely positioned to diagnose and treat obesity, given their role in women's primary health care and the increasing prevalence of obesity-related fertility and pregnancy complications. The metabolic processes of bodyweight regulation are complex, which makes weight-loss maintenance challenging, despite dietary modifications and exercise. Antiobesity medications (AOMs) can facilitate weight loss by targeting appetite regulation. There are four AOMs currently approved for long-term use in the United States, of which liraglutide 3.0 mg is among the most efficacious. Liraglutide 3.0 mg, a glucagon-like peptide-1 receptor agonist (GLP-1 RA), is superior to placebo in achieving weight loss and improving cardiometabolic profile, in both clinical trial and real-world settings. In addition, women with fertility complications receiving liraglutide 1.8–3.0 mg can benefit from improved ovarian function and fertility. Liraglutide 3.0 mg is generally well tolerated, but associated with transient gastrointestinal side effects, which can be mitigated. In this review, we present the risks of obesity and benefits of weight loss for women, and summarize clinical development of GLP-1 RAs for weight management. Finally, we provide practical advice and recommendations for OBGYNs to open the discussion about bodyweight with their patients, initiate lifestyle modification and GLP-1 RA treatment, and help them persist with these interventions to achieve optimal weight loss with associated health benefits.

A synthetic peptide as an allosteric inhibitor of human arginase I and II

Arginine metabolism mediated by arginases plays a critical role in cell and tissue function. The arginine hydrolysis is deeply involved in the urea cycle, which helps the kidney excrete ammonia from blood. Upregulation of arginases affects microenvironment stability due to the presence of excess urea in blood. To regulate the arginase activities properly, a synthetic peptide based on the structure of human arginase I was designed and assessed. Preliminary data shows it inhibits human arginase I and II with an IC₅₀ of 2.4 ± 0.3 and 1.8 ± 0.1 mmol, respectively. Our kinetic analysis indicates the inhibition is not competitive with substrate – suggesting an allosteric mechanism. This result provides a step towards specific inhibitors design.

Effect of C-terminus Conjugation via Different Conjugation Chemistries on In Vivo Activity of Albumin-Conjugated Recombinant GLP-1

Glucagon-like peptide-1 (GLP-1) is a peptide hormone with tremendous therapeutic potential for treating type 2 diabetes mellitus. However, the short half-life of its native form is a significant drawback. We previously prolonged the plasma half-life of GLP-1 via site-specific conjugation of human serum albumin (HSA) at position 16 of recombinant GLP-1 using site-specific incorporation of p-azido-phenylalanine (AzF) and strain-promoted azide-alkyne cycloaddition (SPAAC). However, the resulting conjugate GLP1_8G16AzF-HSA showed only moderate in vivo glucose-lowering activity, probably due to perturbed interactions with GLP-1 receptor (GLP-1R) caused by the albumin-linker. To identify albumin-conjugated GLP-1 variants with enhanced in vivo glucose-lowering activity, we investigated the conjugation of HSA to a C-terminal region of GLP-1 to reduce steric hindrance by the albumin-linker using two different conjugation chemistries. GLP-1 variants GLP1_8G37AzF-HSA and GLP1_8G37C-HSA were prepared using SPAAC and Michael addition, respectively. GLP1_8G37C-HSA exhibited a higher glucose-lowering activity in vivo than GLP1_8G16AzF-HSA, while GLP1_8G37AzF-HSA did not. Another GLP-1 variant, GLP1_8A37C-HSA, had a glycine to alanine mutation at position 8 and albumin at its C-terminus and exhibited in vivo glucose-lowering activity comparable to that of GLP1_8G37C-HSA, despite a moderately shorter plasma half-life. These results showed that site-specific HSA conjugation to the C-terminus of GLP-1 via Michael addition could be used to generate GLP-1 variants with enhanced glucose-lowering activity and prolonged plasma half-life in vivo.

Metabolic Messengers: glucagon-like peptide 1

Glucagon like peptide-1 (GLP-1), a peptide hormone from the intestinal tract, plays a central role in the coordination of postprandial glucose homeostasis through actions on insulin secretion, food intake and gut motility. GLP-1 forms the basis for a variety of current drugs for the treatment of type 2 diabetes and obesity, as well as new agents currently being developed. Here, we provide a concise overview of the core physiology of GLP-1 secretion and action, and the role of the peptide in human health, disease and therapeutics.