Development of Cagrilintide, a Long-Acting Amylin Analogue

Amylin: emergent therapeutic opportunities in overweight, obesity and diabetes mellitus

The identification of amylin as a glucoregulatory peptide hormone with roles in meal-ending satiation sparked a surge of experimental development, which culminated in the amylin mimetic drug pramlintide. Pramlintide was approved by the FDA in 2005 for the treatment of type 1 diabetes mellitus and insulin-requiring type 2 diabetes, and was also explored as a novel anti-obesity treatment. Despite this exciting potential, efforts to develop an amylin-based anti-obesity therapeutic stalled owing to challenges around dosage frequency, safety and formulation. Generally, anti-obesity therapies have displayed modest efficacy and mixed safety profiles, leaving a clear unmet clinical need that requires addressing. Advances in peptide chemistry have reinvigorated the amylin field by enabling the manufacture of effective new amylin-based molecules, resulting in therapeutics that are now on the cusp of approval. At present, there are growing concerns around GLP1 receptor agonist-based therapeutics, in particular their association with loss of lean body mass. Additionally, treatment of patients with overweight or obesity without associated comorbidities is increasingly common. The widespread pharmacotherapy of otherwise healthy populations with overweight or obesity with the goal of improving future health requires further regulatory and ethical consideration. This Review describes how amylin controls energy homeostasis and provides a current overview of amylin-based therapeutic development.

GLP-1-based therapies for diabetes, obesity and beyond

Glucagon-like peptide 1 (GLP-1)-based therapies, such as semaglutide and tirzepatide, represent highly effective treatment options for people with type 2 diabetes and obesity, enabling effective control of glucose and weight loss, while reducing cardiovascular and renal morbidity and mortality. The success of these medicines has spurred development of next-generation GLP-1-based drugs, promising greater weight loss, improved tolerability and additional options for the route and frequency of dosing. This Review profiles established and emerging GLP-1-based medicines, discussing optimization of pharmacokinetics and tolerability, engagement of new therapeutically useful pathways and safety aspects. Structurally unique GLP-1-based medicines that achieve substantially greater and rapid weight loss may impact musculoskeletal health, providing a rationale for therapeutics that more selectively target adipose tissue loss while preserving muscle mass and strength. Ongoing clinical trials in peripheral vascular disease, neuropsychiatric and substance use disorders, metabolic liver disease, arthritis, hypertension and neurodegenerative disorders may broaden indications for GLP-1-based therapeutics.

Structural and dynamic features of cagrilintide binding to calcitonin and amylin receptors

Obesity is a major and increasingly prevalent chronic metabolic disease with numerous comorbidities. While recent incretin-based therapies have provided pharmaceutical inroads into treatment of obesity, there remains an ongoing need for additional medicines with distinct modes of action as independent or complementary therapeutics. Among the most promising candidates, supported by phase 1 and 2 clinical trials, is cagrilintide, a long-acting amylin and calcitonin receptor agonist. As such, understanding how cagrilintide functionally engages target receptors is critical for future development of this target class. Here, we determine structures of cagrilintide bound to Gs-coupled, active, amylin receptors (AMY1R, AMY2R, AMY3R) and calcitonin receptor (CTR) and compare cagrilintide interactions and the dynamics of receptor complexes with previously reported structures of receptors bound to rat amylin, salmon calcitonin or recently developed amylin-based peptides. These data reveal that cagrilintide has an amylin-like binding mode but, compared to other peptides, induces distinct conformational dynamics at calcitonin-family receptors that could contribute to its clinical efficacy.

An update on current type 2 diabetes mellitus (T2DM) druggable targets and drugs targeting them

Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia and affects millions of people globally. Even after advancement and development in medical science, it is a big task to achieve victory over type 2 diabetes mellitus (T2DM). T2DM can be a reason for fatal events like stroke, cardiac failure, nephropathy, and retinopathy. Many advanced antidiabetic drugs have been introduced in the market in the past two decades, leading researchers to hunt for new target proteins and their potential modulators that can help develop newer antidiabetic drugs. This review article comprises a broad literature of the latest developments in the management of T2DM concerning new target proteins, their inhibitors, or drugs from the clinical arena employed for the successful management of symptoms of T2DM using mono, dual, or triple combination medication therapy. The review categorizes antidiabetic drugs into three general classes that include conventional drug targets, currently explored targets, and upcoming emerging targets. The review aims to merge information on the medicines affecting these targets, their mechanisms, followed by the chemical structures, and recent advancements.

From lead to market: chemical approaches to transform peptides into therapeutics

Peptides are a powerful drug modality with potential to access difficult targets. This recognition underlies their growth in the global pharmaceutical market, with peptides representing ~8% of drugs approved by the FDA over the past decade. Currently, the peptide therapeutic landscape is evolving, with high-throughput display technologies driving the identification of peptide leads with enhanced diversity. Yet, chemical modifications remain essential for improving the 'drug-like' properties of peptides and ultimately translating leads to market. In this review, we explore two recent therapeutic candidates (semaglutide, a peptide hormone analogue, and MK-0616, an mRNA display-derived candidate) as case studies that highlight general approaches to improving pharmacokinetics (PK) and potency. We also emphasize the critical link between advances in medicinal chemistry and the optimisation of highly efficacious peptide therapeutics.

Feasibility of a direct binding electrochemiluminescence assay to detect anti-drug antibodies against therapeutic peptides

The emergence of anti-drug antibodies (ADAs) poses significant impacts on the bioactivity and toxicity of biotherapeutics including proteins and peptides. Developing reliable assays to monitor the magnitudes of ADAs in blood samples is therefore considered a crucial task in animal and human studies throughout the development of biotherapeutics. Peptides represent a significant and fast-growing category of biotherapeutics for the management of a variety of indications. While peptides generally exhibit lower immunogenicity risks compared to biologics of larger sizes, drug developers are still required to conduct the risk-based immunogenicity assessment as mandated by the regulatory authorities. To address the need for efficient detection of ADAs against therapeutic peptides, we established a straightforward electrochemiluminescence immunoassay (ECLIA) based on direct binding strategy. Our assay demonstrates its applicability across various peptide therapeutics including marketed drugs and internal investigational compounds. Through stepwise tuning of the assay procedure, we identified several key factors such as buffer, detection reagent, plate type, and conjugation strategy that collectively contribute to the assay performance. Depending on the drug molecule and positive control antibody, the assay can achieve low single-digit to two-digit ng/ml sensitivity and ideal drug tolerance. In conclusion, this ECLIA platform presents a valuable and generic tool to expedite the development and validation of ADA assays for peptide-based therapeutics.

Novel neural pathways targeted by GLP-1R agonists and bariatric surgery

The glucagon-like peptide 1 receptor (GLP-1R) agonist semaglutide has revolutionized the treatment of obesity, with other gut hormone-based drugs lined up that show even greater weight-lowering ability in obese patients. Nevertheless, bariatric surgery remains the mainstay treatment for severe obesity and achieves unparalleled weight loss that generally stands the test of time. While their underlying mechanisms of action remain incompletely understood, it is clear that the common denominator between GLP-1R agonists and bariatric surgery is that they suppress food intake by targeting the brain. In this Review, we highlight recent preclinical studies using contemporary neuroscientific techniques that provide novel concepts in the neural control of food intake and body weight with reference to endogenous GLP-1, GLP-1R agonists, and bariatric surgery. We start in the periphery with vagal, intestinofugal, and spinal sensory nerves and then progress through the brainstem up to the hypothalamus and finish at non-canonical brain feeding centers such as the zona incerta and lateral septum. Further defining the commonalities and differences between GLP-1R agonists and bariatric surgery in terms of how they target the brain may not only help bridge the gap between pharmacological and surgical interventions for weight loss but also provide a neural basis for their combined use when each individually fails.

Central nervous system pathways targeted by amylin in the regulation of food intake

Amylin is a peptide hormone co-released with insulin from pancreatic β-cells during a meal and primarily serves to promote satiation. While the caudal hindbrain was originally implicated as a major site of action in this regard, it is becoming increasingly clear that amylin recruits numerous central nervous system pathways to exert multifaceted effects on food intake. In this Review, we discuss the evidence derived from preclinical studies showing that amylin and the related peptide salmon calcitonin (sCT) directly or indirectly target genetically distinct neurons in the caudal hindbrain (nucleus tractus solitarius and area postrema), rostral hindbrain (lateral parabrachial nucleus), midbrain (lateral dorsal tegmentum and ventral tegmental area) and hypothalamus (arcuate nucleus and parasubthalamic nucleus) via activation of amylin and/or calcitonin receptors. Given that the stable amylin analogue cagrilintide is under clinical development for the treatment of obesity, it is important to determine whether this drug recruits overlapping or distinct central nervous system pathways to that of amylin and sCT with implications for minimising any aversive effects it potentially causes. Such insight will also be important to understand how amylin and sCT analogues synergize with other molecules as part of dual or triple agonist therapies for obesity, especially the glucagon-like peptide 1 receptor (GLP-1R) agonist semaglutide, which has been shown to synergistically lower body weight with cagrilintide (CagriSema) in clinical trials.

A Cross-Species Atlas of the Dorsal Vagal Complex Reveals Neural Mediators of Cagrilintide's Effects on Energy Balance

Amylin analogs, including potential anti-obesity therapies like cagrilintide, act on neurons in the brainstem dorsal vagal complex (DVC) that express calcitonin receptors (CALCR). These receptors, often combined with receptor activity-modifying proteins (RAMPs), mediate the suppression of food intake and body weight. To understand the molecular and neural mechanisms of cagrilintide action, we used single-nucleus RNA sequencing to define 89 cell populations across the rat, mouse, and non-human primate caudal brainstem. We then integrated spatial profiling to reveal neuron distribution in the rat DVC. Furthermore, we compared the acute and long-term transcriptional responses to cagrilintide across DVC neurons of rats, which exhibit strong cagrilintide responsiveness, and mice, which respond poorly to cagrilintide over the long term. We found that cagrilintide promoted long-term transcriptional changes, including increased prolactin releasing hormone (Prlh) expression, in the nucleus of the solitary tract (NTS) Calcr/Prlh cells in rats, but not in mice, suggesting the importance of NTS Calcr/Prlh cells for sustained weight loss. Indeed, activating rat area postrema Calcr cells briefly reduced food intake but failed to decrease food intake or body weight over the long term. Overall, these results not only provide a cross-species and spatial atlas of DVC cell populations but also define the molecular and neural mediators of acute and long-term cagrilintide action.

An Overview of Existing and Emerging Weight-Loss Drugs to Target Obesity-Related Complications: Insights from Clinical Trials

Obesity requires treatment as it is associated with health problems such as type 2 diabetes, hypertension, dyslipidemia, cardiovascular diseases, and some cancers, which increase mortality rates. Achieving sufficient weight loss to reduce obesity-related diseases requires a variety of interventions, including comprehensive lifestyle modification of diet and exercise, change in behavior, anti-obesity medications, and surgery. To date, anti-obesity agents with various mechanisms of action have been developed, and mostly reduce energy intake, resulting in weight loss of about 5% to 10% compared to baseline. Recently developed drugs and those currently under development have been shown to reduce body weight by more than 10% and are expected to reduce obesity-related complications. This article summarizes existing and emerging anti-obesity medications, with a particular focus on those evaluated in clinical trials.

Modulation of amylin and calcitonin receptor activation by hybrid peptides

Calcitonin peptide hormone controls calcium homeostasis by activating the calcitonin receptor. When the calcitonin receptor forms a complex with an accessory protein, the complex functions as the receptors for another peptide hormone amylin. The amylin receptors are the drug target for diabetes and obesity treatment. Since human amylin can produce aggregates, rat amylin that does not form aggregates has been commonly used for research. Interestingly, calcitonin originated from salmons was reported to interact with human amylin receptors with higher affinity/potency than endogenous rat amylin. Here, the peptide hybrid was made of a rat amylin N-terminal fragment and a salmon calcitonin C-terminal fragment. This novel hybrid peptide showed higher potency for human amylin receptor 1/2 activation by 6- to 8-fold than endogenous rat amylin. To further examine the role of the peptide C-terminal fragment in receptor activation, another hybrid peptide was made where salmon calcitonin N-terminal 21 amino acids were fused with rat amylin C-terminal 11 amino acids. The rat amylin C-terminal fragment was previously reported to have relatively low affinity for calcitonin receptor extracellular domain. As expected, this calcitonin-amylin hybrid peptide decreased the potency for calcitonin receptor activation by 3-fold compared to salmon calcitonin. The hybrid strategy used in this study significantly changed the peptide potency for amylin and calcitonin receptor activation. These results provide insight into the role of peptide C-terminal fragments in modulating amylin and calcitonin receptor activation.

Cagrilintide is not associated with clinically relevant QTc prolongation: A thorough QT study in healthy participants

AIMS

The combination of cagrilintide and semaglutide (CagriSema) is being developed for the treatment of obesity and type 2 diabetes. The objective of this thorough QT study was to confirm that cagrilintide does not result in a clinically relevant prolongation in cardiac repolarization compared with placebo.

MATERIALS AND METHODS

This was a double-blind study (NCT05804162) in which healthy participants were randomized to cagrilintide, administered as a once-weekly subcutaneous injection dose escalated to 4.5 mg, or a placebo. The primary end point was the time-matched change from baseline in Fridericia heart rate-corrected QT interval (QTcF) at 12-, 24-, 48- and 72 h after the last cagrilintide 4.5-mg dose. To conclude that cagrilintide does not induce a clinically relevant prolongation, the upper limit of the two-sided 90% confidence interval (CI) for the treatment difference at each of the four time points must fall below 10 ms. To establish QT assay sensitivity, participants in the placebo arms received a single 400-mg oral moxifloxacin dose as a positive control and moxifloxacin placebo in a nested cross-over fashion.

RESULTS

A total of 105 participants received cagrilintide (n = 53) or placebo (n = 52). No clinically relevant QTcF prolongation occurred after the last cagrilintide 4.5-mg dose; the upper limits of the two-sided 90% CIs of the placebo-adjusted QTcF changes from baseline were below 10 ms at all time points. QT assay sensitivity was demonstrated with moxifloxacin as a positive control.

CONCLUSIONS

Cagrilintide did not result in clinically relevant QTcF prolongation, indicating no increased risk of ventricular tachyarrhythmias.

Amylin receptor subunit interactions are modulated by agonists and determine signaling

Three amylin receptors (AMYRs) mediate the metabolic actions of the peptide hormone amylin and are drug targets for diabetes and obesity. AMY1R, AMY2R, and AMY3R are heterodimers consisting of the G protein-coupled calcitonin receptor (CTR) paired with a RAMP1, -2, or -3 accessory subunit, respectively, which increases amylin potency. Little is known about AMYR subunit interactions and their role in signaling. Here, we show that the AMYRs have distinct basal subunit equilibriums that are modulated by peptide agonists and determine the cAMP signaling phenotype. Using a novel biochemical assay that resolves the AMYR heterodimers and free subunits, we found that the AMY1/2R subunit equilibriums favored free CTR and RAMP1/2, and rat amylin and αCGRP agonists promoted subunit association. A stronger CTR-RAMP3 transmembrane domain interface yielded a more stable AMY3R, and human and salmon calcitonin agonists promoted AMY3R dissociation. Similar changes in subunit association-dissociation were observed in live cell membranes, and G protein coupling and cAMP signaling assays showed how these altered signaling. Our findings reveal regulation of heteromeric GPCR signaling through subunit interaction dynamics.

Establishing a Relationship between In Vitro Potency in Cell-Based Assays and Clinical Efficacious Concentrations for Approved GLP-1 Receptor Agonists

Background: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) play an important role in the treatment of type 2 diabetes (T2D) and obesity. The relationship between efficacy and dosing regimen has been studied extensively for this class of molecules. However, a comprehensive analysis of the translation of in vitro data to in vivo efficacious exposure is still lacking. Methods: We collected clinical pharmacokinetics for five approved GLP-1RAs to enable the simulation of exposure profiles and compared published clinical efficacy endpoints (HbA1c and body weight) with in-house in vitro potency values generated in different cell-based assays. Additionally, we investigated the correlation with target coverage, expressed as a ratio between the steady state drug exposure and unbound potency, body weight, or HbA1c reduction in patients with T2D. Results: We found that the best correlation with in vivo efficacy was seen for in vitro potency data generated in cellular assays performed in the absence of any serum albumin or using ovalbumin. Residual variability was larger using in vitro potency data generated in endogenous cell lines or in the presence of human serum albumin. For the human receptor assay with no albumin, exposures above 100-fold in vitro EC50 resulted in >1.5% point HbA1c reduction, while a 5% BW reduction was related to approximately 3× higher exposures. A similar relationship was seen in the ovalbumin assay. Conclusions: Overall, the relationship established for in vitro potency and in vivo efficacy will help to increase confidence in human dose prediction and trial design for new GLP-1RAs in the discovery and early clinical phases.

Updates in pharmacotherapy of obesity

Obesity is now recognized as a chronic, progressive condition requiring early intervention and long-term management to achieve health benefits and improve metabolic risk factors. The main objective of obesity pharmacotherapy is weight loss and weight loss maintenance. There is increasing acceptance of anti-obesity medications as an adjunct to lifestyle modifications and/or surgery. In recent years there has been an evolution in management approach and pharmacologic options for treatment. As a result, there is increased focus on the efficacy and safety of these agents. We provide a historical perspective, review of recent studies on anti-obesity medication outcomes showing efficacy, potential side effects and promising therapies in development.

Amylin analogs for the treatment of obesity without diabetes: present and future

INTRODUCTION

Obesity is a pandemic, linked with increased morbidity including diabetes mellitus (DM) and certain cancer types. Amylin is a major regulatory hormone for satiation and food intake perception in humans. Amylin analogs (pramlintide and cagrilintide) are emerging as promising anti-obesity agents in non-DM subjects.

AREAS COVERED

Pramlintide, the first amylin analog, initially used for the treatment of both type 1 and type 2 DM, has demonstrated weight-lowering action. Clinical trials confirmed a weight loss exceeding 3% in the study period without major untoward effects, which was maintained beyond the follow-up period. Recently, cagrilintide, a long-lasting synthetic amylin analog has been introduced. Cagrilintide has achieved adequate weight loss, reaching even more than 10% of the total weight in early clinical trials. However, adverse gastrointestinal effects, particularly nausea, were more frequent compared with pramlintide. Clinical trials have also confirmed the effectiveness of cagrilintide in comparison with glucagon-like peptide 1 receptor agonists.

EXPERT OPINION

Amylin analogs will certainly enrich the growing therapeutic armamentarium aimed at tackling obesity. The most exciting future research venue could be the development of their combinations with other weight-lowering drugs, especially dual and triple incretin-based co-agonists, thus potentially providing massive weight-loss effects.

Approved and Emerging Hormone-Based Anti-Obesity Medications: A Review Article

Obesity is a heterogeneous, complex, and chronic disease that has a detrimental impact on disability-adjusted life years across the globe. Recent advancements in our understanding of gut-brain communication at the molecular level have driven the development of next-generation anti-obesity medications (AOMs). Glucagon-like peptide-1 receptor agonists (GLP1RAs) remain the front-runners in this rapidly evolving landscape of hormone-based AOMs. Two GLP1RAs, namely Liraglutide and Semaglutide, have been approved by the Food and Drug Administration (FDA) and European Medicine Agency (EMA) for use in clinical practice for weight loss. Three oral GLP1RAs, namely Semaglutide, Danuglipron, and Orforglipron, are undergoing advanced clinical trials in individuals with obesity. Amylin receptor agonist (AMYRA) Cagrilintide, when used alone or in combination with Semaglutide, has demonstrated substantial weight reduction in clinical trials. Tirzepatide, a dual agonist for the glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptors, has been observed to be associated with a significant placebo-subtracted weight reduction of 17.8% in a 72-week randomized controlled trial. Novel approaches targeting glucagon signalling have also yielded promising preliminary results. Three long-acting GLP1R/glucagon receptor (GCGR) dual agonists, namely Survodutide, Mazdutide, and Pemvidutide, exhibited significant weight loss in clinical trials. Retatrutide, a GLP1R/GCGR/GIPR tri-agonist, has been associated with a placebo-subtracted weight reduction of -22.1% in a 48-week phase-II trial. As a note of caution, long-term data on such medications' safety and cardiovascular benefits is yet to be ascertained. Our review provides a comprehensive overview of the approved and emerging hormone-based AOMs, highlighting the diversity of options that might become available in the near future.

Toward once-monthly insulin therapy via synergy in two pharmacokinetic protractors: Fc-conjugation and fatty acid acylation

Pharmacokinetic properties and duration of therapeutic action of a pharmaceutical agent can be significantly extended through the combination of two distinct strategies aimed at increasing plasma half-life: fatty acid acylation and Fc-conjugation. Using insulin as a case study, we demonstrate that a doubly protracted insulin analog produces a substantial prolongation of pharmacodynamic effect to lower blood glucose in STZ-treated mice when compared to the Fc-only counterparts. This enhancement is further corroborated by direct pharmacokinetic measurements in rat and dog models, demonstrating the potential for once-monthly insulin therapy. The results suggest that this approach might have broad application across a diverse spectrum of peptide- and protein-based therapeutics.

Machine-Learning-Guided Peptide Drug Discovery: Development of GLP-1 Receptor Agonists with Improved Drug Properties

Peptide-based drug discovery has surged with the development of peptide hormone-derived analogs for the treatment of diabetes and obesity. Machine learning (ML)-enabled quantitative structure-activity relationship (QSAR) approaches have shown great promise in small molecule drug discovery but have been less successful in peptide drug discovery due to limited data availability. We have developed a peptide drug discovery platform called streaMLine, enabling rigorous design, synthesis, screening, and ML-driven analysis of large peptide libraries. Using streaMLine, this study systematically explored secretin as a peptide backbone to generate potent, selective, and long-acting GLP-1R agonists with improved physicochemical properties. We synthesized and screened a total of 2688 peptides and applied ML-guided QSAR to identify multiple options for designing stable and potent GLP-1R agonists. One candidate, GUB021794, was profiled in vivo (S.C., 10 nmol/kg QD) and showed potent body weight loss in diet-induced obese mice and a half-life compatible with once-weekly dosing.

NN1213 - A Potent, Long-Acting, and Selective Analog of Human Amylin

Amylin, a member of the calcitonin family, acts via amylin receptors in the hindbrain and hypothalamus to suppress appetite. Native ligands of these receptors are peptides with short half-lives. Conjugating fatty acids to these peptides can increase their half-lives. The long-acting human amylin analog, NN1213, was generated from structure-activity efforts optimizing solubility, stability, receptor affinity, and selectivity, as well as in vivo potency and clearance. In both rats and dogs, a single dose of NN1213 reduced appetite in a dose-dependent manner and with a long duration of action. Consistent with the effect on appetite, studies in obese rats demonstrated that daily NN1213 dosing resulted in a dose-dependent reduction in body weight over a 21-day period. Magnetic resonance imaging indicated that this was primarily driven by loss of fat mass. Based on these data, NN1213 could be considered an attractive option for weight management in the clinical setting.

Type-2 Diabetes, Pancreatic Amylin, and Neuronal Metabolic Remodeling in Alzheimer's Disease

Type-2 diabetes raises the risk for Alzheimer's disease (AD)-type dementia and the conversion from mild cognitive impairment to dementia, yet mechanisms connecting type-2 diabetes to AD remain largely unknown. Amylin, a pancreatic β-cell hormone co-secreted with insulin, participates in the central regulation of satiation, but also forms pancreatic amyloid in persons with type-2 diabetes and synergistically interacts with brain amyloid β (Aβ) pathology, in both sporadic and familial Alzheimer's disease (AD). Growing evidence from studies of tumor growth, together with early observations in skeletal muscle, indicates amylin as a potential trigger of cellular metabolic reprogramming. Because the blood, cerebrospinal fluid, and brain parenchyma in humans with AD have increased concentrations of amylin, amylin-mediated pathological processes in the brain may involve neuronal metabolic remodeling. This review summarizes recent progress in understanding the link between prediabetic hypersecretion of amylin and risk of neuronal metabolic remodeling and AD and suggests nutritional and medical effects of food constituents that might prevent and/or ameliorate amylin-mediated neuronal metabolic remodeling.

Identification and utility exploration of a highly potent and long-acting bullfrog GLP-1 analogue in GLP-1 and amylin combination therapy

This study assesses the efficacy of an innovative therapeutic approach that combines GLP-1 and amylin analogues for weight reduction. Focusing on GLP-1 analogues from bullfrog (Rana catesbeiana), we designed ten bGLP-1 analogues with various modifications. Among them, bGLP-10 showed high potency in binding and activating GLP-1 receptors, with superior albumin affinity. In diet-induced obesity (DIO) mice fed a high-fat diet, bGLP-10 demonstrated significant superiority over semaglutide in reducing blood sugar and food intake at a dose of 10 nmol/kg (P < 0.001). Notably, in a chronic study involving DIO mice, the combination of bGLP-10 with the amylin analogue cagrilintide led to a more substantial weight loss (-38.4%, P < 0.001) compared to either the semaglutide-cagrilintide combination (-23.0%) or cagrilintide (-5.7%), bGLP-10 (-16.1%), and semaglutide (-10.9%) alone. Furthermore, the bGLP-10 and cagrilintide combination exhibited superior glucose control and liver lipid management compared to the semaglutide-cagrilintide combination (P < 0.001). These results highlight bGLP-10's potential in GLP-1 and amylin-based therapies and suggest exploring more GLP-1 analogues from natural sources for anti-obesity and anti-diabetic treatments.

Variable CGRP family peptide signaling durations and the structural determinants thereof

Calcitonin gene-related peptides alpha and beta (αCGRP, βCGRP), adrenomedullin (AM), and adrenomedullin 2/intermedin (AM2/IMD) function in pain signaling, neuroimmune communication, and regulation of the cardiovascular and lymphatic systems by activating either of two class B GPCRs, CLR and CTR, in complex with a RAMP1, -2, or -3 modulatory subunit. Inspired by our recent discovery that AM2/IMD(1-47) activation of CLR-RAMP3 elicits long duration cAMP signaling, here we used a live-cell cAMP biosensor assay to characterize the signaling kinetics of the two CGRP peptides and several bioactive AM and AM2/IMD fragments with variable N-terminal extensions. Remarkably, AM2/IMD(8-47) and AM2/IMD-53 exhibited even longer duration signaling than the 1-47 fragment. AM2/IMD(8-47) was a striking 8-fold longer acting than AM(13-52) at CLR-RAMP3. In contrast, the N-terminal extension of AM had no effect on signaling duration. AM(1-52) and (13-52) were equally short-acting. Analysis of AM2/IMD-AM mid-region chimeras and AM2/IMD R23 and R33 point mutants showed the importance of these residues for long-duration signaling and identified AM2/IMD peptides that exhibited up to 17-fold diminished signaling duration at CLR-RAMP3, while retaining near wildtype signaling potencies. βCGRP was ∼ 3-fold longer acting than αCGRP at the CGRP (CLR-RAMP1) and the amylin1 (CTR-RAMP1) receptors. Chimeric CGRP peptides showed that the single residue difference near the N-terminus, and the two differences in the mid-region, equally contributed to the longer duration of βCGRP signaling. This work uncovers key temporal differences in cAMP signaling among the CGRP family peptides, elucidates the structural bases thereof, and provides pharmacological tools for studying long-duration AM2/IMD signaling.

The processing intermediate of human amylin, pro-amylin(1-48), has in vivo and in vitro bioactivity

Amylin is released by pancreatic beta-cells in response to a meal and its major soluble mature form (37 amino acid-peptide) produces its biological effects by activating amylin receptors. Amylin is derived from larger propeptides that are processed within the synthesizing beta-cell. There are suggestions that a partially processed form, pro-amylin(1-48) is also secreted. We tested the hypothesis that pro-amylin(1-48) has biological activity and that human pro-amylin(1-48) may also form toxic pre-amyloid species. Amyloid formation, the ability to cross-seed and in vitro toxicity were similar between human pro-amylin(1-48) and amylin. Human pro-amylin(1-48) was active at amylin-responsive receptors, though its potency was reduced at rat, but not human amylin receptors. Pro-amylin(1-48) was able to promote anorexia by activating neurons of the area postrema, amylin's primary site of action, indicating that amylin can tolerate significant additions at the N-terminus without losing bioactivity. Our studies help to shed light on the possible roles of pro-amylin(1-48) which may be relevant for the development of future amylin-based drugs.

Diabetes: a review of its pathophysiology, and advanced methods of mitigation

Diabetes mellitus (DM) is a long-lasting metabolic non-communicable disease often characterized by an increase in the level of glucose in the blood or hyperglycemia. Approximately, 415 million people between the ages of 20 and 79 years had DM in 2015 and this figure will rise by 200 million by 2040. In a study conducted by CARRS, it's been found that in Delhi the prevalence of diabetes is around 27% and for prediabetic cases, it is more than 46%. The disease DM can be both short-term and long-term and is often associated with one or more diseases like cardiovascular disease, liver disorder, or kidney malfunction. Early identification of diabetes may help avoid catastrophic repercussions because untreated DM can result in serious complications. Diabetes' primary symptoms are persistently high blood glucose levels, frequent urination, increased thirst, and increased hunger. Therefore, DM is classified into four major categories, namely, Type 1, Type 2, Gestational diabetes, and secondary diabetes. There are various oral and injectable formulations available in the market like insulin, biguanides, sulphonylureas, etc. for the treatment of DM. Recent attention can be given to the various nano approaches undertaken for the treatment, diagnosis, and management of diabetes mellitus. Various nanoparticles like Gold Nanoparticles, carbon nanomaterials, and metallic nanoparticles are some of the approaches mentioned in this review. Besides nanotechnology, artificial intelligence (AI) has also found its application in diabetes care. AI can be used for screening the disease, helping in decision-making, predictive population-level risk stratification, and patient self-management tools. Early detection and diagnosis of diabetes also help the patient avoid expensive treatments later in their life with the help of IoT (internet of medical things) and machine learning models. These tools will help healthcare physicians to predict the disease early. Therefore, the Nano drug delivery system along with AI tools holds a very bright future in diabetes care.

Development of a Novel Assay for Direct Assessment of Selective Amylin Receptor Activation Reveals Novel Differences in Behavior of Selective and Nonselective Peptide Agonists

Dual amylin and calcitonin receptor agonists (DACRAs) show promise as efficacious therapeutics for treatment of metabolic disease, including obesity. However, differences in efficacy in vivo have been observed for individual DACRAs, indicating that detailed understanding of the pharmacology of these agents across target receptors is required for rational drug development. To date, such understanding has been hampered by lack of direct, subtype-selective, functional assays for the amylin receptors (AMYRs). Here, we describe the generation of receptor-specific assays for recruitment of Venus-tagged Gs protein through fusion of luciferase to either the human calcitonin receptor (CTR), human receptor activity-modifying protein (RAMP)-1, RAMP1 (AMY1R), human RAMP2 (AMY2R), or human RAMP3 (AMY3R). These assays revealed a complex pattern of receptor activation by calcitonin, amylin, or DACRA peptides that was distinct at each receptor subtype. Of particular note, although both of the CT-based DACRAs, sCT and AM1784, displayed relatively similar behaviors at CTR and AMY1R, they generated distinct responses at AMY2R and AMY3R. These data aid the rationalization of in vivo differences in response to DACRA peptides in rodent models of obesity. Direct assessment of the pharmacology of novel DACRAs at AMYR subtypes is likely to be important for development of optimized therapeutics for treatment of metabolic diseases. SIGNIFICANCE STATEMENT: Amylin receptors (AMYRs) are important obesity targets. Here we describe a novel assay that allows selective functional assessment of individual amylin receptor subtypes that provides unique insight into the pharmacology of potential therapeutic ligands. Direct assessment of the pharmacology of novel agonists at AMYR subtypes is likely to be important for development of optimized therapeutics for treatment of metabolic diseases.

Recent advances in peptide-based therapies for obesity and type 2 diabetes

Options for the treatment of type 2 diabetes mellitus (T2DM) and obesity have recently been expanded by the results of several large clinical trials with incretin-based peptide therapies. Most of these studies have been conducted with the glucagon-like peptide-1 (GLP-1) receptor agonist semaglutide, which is available as a once weekly subcutaneous injection and once daily tablet, and the once weekly injected dual agonist tirzepatide, which interacts with receptors for GLP-1 and glucose-dependent insulinotropic polypeptide (GIP). In individuals with T2DM these therapies have achieved reductions of glycated haemoglobin (HbA1c) by > 2% and lowered body weight by > 10%. In some studies, these agents tested in non-diabetic, obese individuals at much higher doses have lowered body weight by > 15%. Emerging evidence suggests these agents can also offer cardio-protective and potentially reno-protective effects. Other incretin-based peptide therapies in early clinical development, notably a triple GLP-1/GIP/glucagon receptor agonist (retatrutide) and a combination of semaglutide with the amylin analogue cagrilintide (CagriSema), have shown strong efficacy. Although incretin therapies can incur adverse gastrointestinal effects these are for most patients mild-to-moderate and transient but result in cessation of treatment in some cases. Thus, the efficacy of new incretin-based peptide therapies is enhancing the opportunity to control body weight and blood glucose and improve the treatment of T2DM and obesity.

Management of type 2 diabetes, obesity, or nonalcoholic steatohepatitis with high-dose GLP-1 receptor agonists and GLP-1 receptor-based co-agonists

Type 2 diabetes (T2D), obesity, and nonalcoholic fatty liver disease/nonalacoholic steatohepatitis (NAFLD/NASH) share mutual causalities. Medications that may offer clinical benefits to all three conditions are being developed. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are approved for the management of T2D and obesity and there is great interest in evaluating higher doses of available GLP-1RAs and developing novel GLP-1RA-based co-agonists to provide greater reductions in glycated hemoglobin (HbA1c) and body weight as well as modifying NAFLD/NASH complications in clinically meaningful ways. High-dose GLP-1RAs and multi-hormonal strategies including GLP-1R agonism have either already been approved or are in development for managing T2D, obesity, or NASH. We provide a mechanistic outline with a detailed summary of the available clinical data and ongoing trials that are adjudicating the impact of high-dose GLP-1RAs, unimolecular, and multimolecular GLP-1R-based co-agonists in populations living with T2D, obesity, or NASH. The available trial findings are aligned with preclinical observations, showing clinical efficacy and safety thus providing optimism for the expansion of GLP-1R-based drug classes for managing the triad of T2D, obesity and NASH. Development, access, and wide-spread utilization of these new therapeutic approaches will offer important opportunities to markedly improve the collective global burden of T2D, obesity, and NASH.

Structural insight into selectivity of amylin and calcitonin receptor agonists

Amylin receptors (AMYRs), heterodimers of the calcitonin receptor (CTR) and one of three receptor activity-modifying proteins, are promising obesity targets. A hallmark of AMYR activation by Amy is the formation of a 'bypass' secondary structural motif (residues S19-P25). This study explored potential tuning of peptide selectivity through modification to residues 19-22, resulting in a selective AMYR agonist, San385, as well as nonselective dual amylin and calcitonin receptor agonists (DACRAs), with San45 being an exemplar. We determined the structure and dynamics of San385-bound AMY3R, and San45 bound to AMY3R or CTR. San45, via its conjugated lipid at position 21, was anchored at the edge of the receptor bundle, enabling a stable, alternative binding mode when bound to the CTR, in addition to the bypass mode of binding to AMY3R. Targeted lipid modification may provide a single intervention strategy for design of long-acting, nonselective, Amy-based DACRAs with potential anti-obesity effects.

Cagrilintide: A Long-Acting Amylin Analog for the Treatment of Obesity

Despite the worldwide epidemic of obesity, there remain few approved pharmacological treatment options to bridge the gap between lifestyle therapy and bariatric surgery. Cagrilintide is an amylin-analog, now being developed in combination with the GLP-1 agonist semaglutide to achieve sustained weight loss in persons with overweight and obesity. Amylin, released with insulin from beta cells in the pancreas, induces its satiating effect via both the homoeostatic and hedonic regions of the brain. Semaglutide, a GLP-1 receptor agonist, reduces appetite via GLP-1 receptors in the hypothalamus and increases the production of insulin, and reduces glucagon secretion, delaying gastric emptying. These separate, but related mechanisms of action of an amylin-analog and a GLP-1 receptor agonist appear to have an additive effect on appetite reduction. Given the heterogeneity and complex pathogenesis of obesity, combination therapy with multiple pathophysiological targets is a logical approach to increasing weight loss response with pharmacotherapy. Cagrilintide alone, as well as cagrilintide in combination with semaglutide have shown promising weight loss in clinical trials that supports the further development of this therapy for sustained weight management.

Future is Brighter: New Potential Paradigm-Shifting Medications and Regimens for Diabetes and Obesity

Diabetes is a chronic illness that can become debilitating owing to its microvascular and macrovascular complications. Its prevalence is increasing and so is its cost. Diabetes, particularly type 2, appears to have a very close relationship with obesity. While lifestyle modifications, exercises, and current therapeutics have substantially improved clinical outcomes, the need for new therapeutics and regimens continue to exist. Several new medications and regimens for diabetes, obesity, and diabesity are showing promising results in advanced clinical trials. For type 1 diabetes mellitus (T1DM), they include teplizumab, ustekinumab, jakinibs, and cell therapies, whereas for type 2 diabetes mellitus (T2DM), they include once-weakly insulin, tirzepatide, high oral dose of semaglutide, orforglipron, retatrutide, CagriSema, and survodutide. Given their structural and mechanistic diversity as well as their substantial efficacy and safety profiles, these medications and regimens are paradigm shifting and promise a brighter future. They will likely enable better disease prevention and management. This review will provide details about each of the above strategies to keep the scientific community up to date about progress in the fields of diabetes and obesity.

Novel Approaches for the Management of Type 2 Diabetes Mellitus: An Update

Diabetes mellitus is an irreversible, chronic metabolic disorder indicated by hyperglycemia. It is now considered a worldwide pandemic. T2DM, a spectrum of diseases initially caused by tissue insulin resistance and slowly developing to a state characterized by absolute loss of secretory action of the β cells of the pancreas, is thought to be caused by reduced insulin secretion, resistance to tissue activities of insulin, or a combination of both. Insulin secretagogues, biguanides, insulin sensitizers, alpha-glucosidase inhibitors, incretin mimetics, amylin antagonists, and sodium-glucose co-transporter-2 (SGLT2) inhibitors are the main medications used to treat T2DM. Several of these medication's traditional dosage forms have some disadvantages, including frequent dosing, a brief half-life, and limited absorption. Hence, attempts have been made to develop new drug delivery systems for oral antidiabetics to ameliorate the difficulties associated with conventional dosage forms. In comparison to traditional treatments, this review examines the utilization of various innovative therapies (such as microparticles, nanoparticles, liposomes, niosomes, phytosomes, and transdermal drug delivery systems) to improve the distribution of various oral hypoglycemic medications. In this review, we have also discussed some new promising candidates that have been approved recently by the US Food and Drug Administration for the treatment of T2DM, like semaglutide, tirzepatide, and ertugliflozin. They are used as a single therapy and also as combination therapy with drugs like metformin and sitagliptin.

G protein-coupled receptors and obesity

G protein-coupled receptors (GPCRs) have emerged as important drug targets for various chronic diseases, including obesity and diabetes. Obesity is a complex chronic disease that requires long term management predisposing to type 2 diabetes, heart disease, and some cancers. The therapeutic landscape for GPCR as targets of anti-obesity medications has undergone significant changes with the approval of semaglutide, the first peptide glucagon like peptide 1 receptor agonist (GLP-1RA) achieving double digit weight loss (≥10%) and cardiovascular benefits. The enhanced weight loss, with the expected beneficial effect on obesity-related complications and reduction of major adverse cardiovascular events (MACE), has propelled the commercial opportunity for the obesity market leading to new players entering the space. Significant progress has been made on approaches targeting GPCRs such as single peptides that simultaneously activate GIP and/or GCGR in addition to GLP1, oral tablet formulation of GLP-1, small molecules nonpeptidic oral GLP1R and fixed-dose combination as well as add-on therapy for patients already treated with a GLP-1 agonist.

Recent advances in the development of therapeutic peptides

Peptides have unique characteristics that make them highly desirable as therapeutic agents. The physicochemical and proteolytic stability profiles determine the therapeutic potential of peptides. Multiple strategies to enhance the therapeutic profile of peptides have emerged. They include chemical modifications, such as cyclization, substitution with d-amino acids, peptoid formation, N-methylation, and side-chain halogenation, and incorporation in delivery systems. There have been recent advances in approaches to discover peptides having these modifications to attain desirable therapeutic properties. We critically review these recent advancements in therapeutic peptide development.

An updated patent review of GLP-1 receptor agonists (2020-present)

INTRODUCTION

Type 2 diabetes (T2DM) and obesity present significant global health issues, requiring the development of long-lasting and highly effective pharmacotherapies. Although glucagon-like peptide-1 receptor agonists (GLP-1RAs) are commonly used for diabetes treatment, their potential for addressing obesity is still being explored.

AREAS COVERED

This review offers a comprehensive overview of recently published patents from January 2020 to July 2023, focusing on modified GLP-1RAs, small molecule GLP-1RAs, GLP-1 R-based multi-agonists, GLP-1RA-based fusion proteins, and combination therapies. The patents discussed pertain to the treatment and prevention of diabetes and obesity. Patent searches were conducted using the PATENTSCOPE database of the World Intellectual Property Organization, using the keywords GLP-1, GLP-1/GIP, GLP-1/GCG, and GLP-1/GCG/GIP.

EXPERT OPINION

In recent years, patents have emphasized two main goals for developing GLP-1RAs drugs: oral delivery and improved weight reduction effects. To address the growing demand for improved treatments, researchers have focused their efforts on developing GLP-1 R-based multi-agonists, orally administered GLP-1RAs, and combination therapies utilizing GLP-1RAs. These new approaches offer promising benefits, such as improved effectiveness by targeting multiple pathways and reduced side effects. Additionally, the development of new uses, oral forms, and long-lasting preparations will be crucial in shaping the future market potential of GLP-1 drugs.

New Long-Acting [89Zr]Zr-DFO GLP-1 PET Tracers with Increased Molar Activity and Reduced Kidney Accumulation

Positron emission tomography (PET) imaging is used in drug development to noninvasively measure biodistribution and receptor occupancy. Ideally, PET tracers retain target binding and biodistribution properties of the investigated drug. Previously, we developed a zirconium-89 PET tracer based on a long-circulating glucagon-like peptide 1 receptor agonist (GLP-1RA) using desferrioxamine (DFO) as a chelator. Here, we aimed to develop an improved zirconium-89-labeled GLP-1RA with increased molar activity to increase the uptake in low receptor density tissues, such as brain. Furthermore, we aimed at reducing tracer accumulation in the kidneys. Introducing up to four additional Zr-DFOs resulted in higher molar activity and stability, while retaining potency. Branched placement of DFOs was especially beneficial. Tracers with either two or four DFOs had similar biodistribution as the tracer with one DFO in vivo, albeit increased kidney and liver uptake. Reduced kidney accumulation was achieved by introducing an enzymatically cleavable Met-Val-Lys (MVK) linker motif between the chelator and the peptide.

Treatment sequencing using the dual amylin and calcitonin receptor agonist KBP-336 and semaglutide results in durable weight loss

OBJECTIVE

Long-acting dual amylin and calcitonin receptor agonists (DACRAs) hold great promise as potential treatments for obesity and its associated comorbidities. These agents have demonstrated beneficial effects on body weight, glucose control, and insulin action mirroring the effects observed with glucagon-like peptide-1 (GLP-1) agonist treatment. Strategies aimed at enhancing and prolonging treatment efficacy include treatment sequencing and combination therapy. Here, we sought to investigate the impact of switching between or combining treatment with the DACRA KBP-336 and the GLP-1 analog semaglutide in fed rats with obesity induced by a high-fat diet (HFD).

METHODS

Two studies were performed in which HFD-induced obese Sprague Dawley rats were switched between treatment with KBP-336 (4.5 nmol/kg, Q3D) and semaglutide (50 nmol/kg, Q3D) or a combination of the two. Treatment efficacy on weight loss and food intake was evaluated, and glucose tolerance was assessed by oral glucose tolerance tests.

RESULTS

KBP-336 and semaglutide monotherapy resulted in a similar reduction in body weight and food intake. Treatment sequencing resulted in continuous weight loss and all monotherapies resulted in similar weight loss independent of the treatment regimen (P < 0.001 compared to vehicle). The combination of KBP-336 and semaglutide significantly improved the weight loss compared to either monotherapy alone (P < 0.001), which was evident in the adiposity at the study end. All treatments improved glucose tolerance, with the KBP-effect on insulin sensitivity as the dominant response.

CONCLUSIONS

These findings highlight KBP-336 as a promising anti-obesity therapy both alone, in treatment sequencing, and in combination with semaglutide or other incretin-based therapies.

Pharmacotherapy for chronic obesity management: a look into the future

Substantial leaps have been made in the drug discovery front in tackling the growing pandemic of obesity and its metabolic co-morbidities. Greater mechanistic insight and understanding of the gut-brain molecular pathways at play have enabled the pursuit of novel therapeutic agents that possess increasingly efficacious weight-lowering potential whilst remaining safe and tolerable for clinical use. In the wake of glucagon-like peptide 1 (GLP-1) based therapy, we look at recent advances in gut hormone biology that have fermented the development of next generation pharmacotherapy in diabesity that harness synergistic potential. In this paper, we review the latest data from the SURPASS and SURMOUNT clinical trials for the novel 'twincretin', known as Tirzepatide, which has demonstrated sizeable body weight reduction as well as glycaemic efficacy. We also provide an overview of amylin-based combination strategies and other emerging therapies in the pipeline that are similarly providing great promise for the future of chronic management of obesity.

Obesity and Type 2 Diabetes: Adiposopathy as a Triggering Factor and Therapeutic Options

Obesity and type 2 diabetes (T2DM) are major public health concerns associated with serious morbidity and increased mortality. Both obesity and T2DM are strongly associated with adiposopathy, a term that describes the pathophysiological changes of the adipose tissue. In this review, we have highlighted adipose tissue dysfunction as a major factor in the etiology of these conditions since it promotes chronic inflammation, dysregulated glucose homeostasis, and impaired adipogenesis, leading to the accumulation of ectopic fat and insulin resistance. This dysfunctional state can be effectively ameliorated by the loss of at least 15% of body weight, that is correlated with better glycemic control, decreased likelihood of cardiometabolic disease, and an improvement in overall quality of life. Weight loss can be achieved through lifestyle modifications (healthy diet, regular physical activity) and pharmacotherapy. In this review, we summarized different effective management strategies to address weight loss, such as bariatric surgery and several classes of drugs, namely metformin, GLP-1 receptor agonists, amylin analogs, and SGLT2 inhibitors. These drugs act by targeting various mechanisms involved in the pathophysiology of obesity and T2DM, and they have been shown to induce significant weight loss and improve glycemic control in obese individuals with T2DM.

An update on peptide-based therapies for type 2 diabetes and obesity

Long-acting analogues of the naturally occurring incretin, glucagon-like peptide-1 (GLP-1) and those modified to interact also with receptors for glucose-dependent insulinotropic polypeptide (GIP) have shown high glucose-lowering and weight-lowering efficacy when administered by once-weekly subcutaneous injection. These analogues herald an exciting new era in peptide-based therapy for type 2 diabetes (T2D) and obesity. Of note is the GLP-1R agonist semaglutide, available in oral and injectable formulations and in clinical trials combined with the long-acting amylin analogue, cagrilintide. Particularly high efficacy in both glucose- and weight lowering capacities has also been observed with the GLP-1R/GIP-R unimolecular dual agonist, tirzepatide. In addition, a number of long-acting unimolecular GLP-1R/GCGR dual agonist peptides and GLP-1R/GCGR/GIPR triagonist peptides have entered clinical trials. Other pharmacological approaches to chronic weight management include the human monoclonal antibody, bimagrumab which blocks activin type II receptors and is associated with growth of skeletal muscle, an antibody blocking activation of GIPR to which are conjugated GLP-1R peptide agonists (AMG-133), and the melanocortin-4 receptor agonist, setmelanotide for use in certain inherited obesity conditions. The high global demand for the GLP-1R agonists liraglutide and semaglutide as anti-obesity agents has led to shortage so that their use in T2D therapy is currently being prioritized.

Elucidating the Interactome of G Protein-Coupled Receptors and Receptor Activity-Modifying Proteins

G protein-coupled receptors (GPCRs) are known to interact with several other classes of integral membrane proteins that modulate their biology and pharmacology. However, the extent of these interactions and the mechanisms of their effects are not well understood. For example, one class of GPCR-interacting proteins, receptor activity-modifying proteins (RAMPs), comprise three related and ubiquitously expressed single-transmembrane span proteins. The RAMP family was discovered more than two decades ago, and since then GPCR-RAMP interactions and their functional consequences on receptor trafficking and ligand selectivity have been documented for several secretin (class B) GPCRs, most notably the calcitonin receptor-like receptor. Recent bioinformatics and multiplexed experimental studies suggest that GPCR-RAMP interactions might be much more widespread than previously anticipated. Recently, cryo-electron microscopy has provided high-resolution structures of GPCR-RAMP-ligand complexes, and drugs have been developed that target GPCR-RAMP complexes. In this review, we provide a summary of recent advances in techniques that allow the discovery of GPCR-RAMP interactions and their functional consequences and highlight prospects for future advances. We also provide an up-to-date list of reported GPCR-RAMP interactions based on a review of the current literature. SIGNIFICANCE STATEMENT: Receptor activity-modifying proteins (RAMPs) have emerged as modulators of many aspects of G protein-coupled receptor (GPCR)biology and pharmacology. The application of new methodologies to study membrane protein-protein interactions suggests that RAMPs interact with many more GPCRs than had been previously known. These findings, especially when combined with structural studies of membrane protein complexes, have significant implications for advancing GPCR-targeted drug discovery and the understanding of GPCR pharmacology, biology, and regulation.

Derivatization with fatty acids in peptide and protein drug discovery

Peptides and proteins are widely used to treat a range of medical conditions; however, they often have to be injected and their effects are short-lived. These shortcomings of the native structure can be addressed by molecular engineering, but this is a complex undertaking. A molecular engineering technology initially applied to insulin - and which has now been successfully applied to several biopharmaceuticals - entails the derivatization of peptides and proteins with fatty acids. Various protraction mechanisms are enabled by the specific characteristics and positions of the attached fatty acid. Furthermore, the technology can ensure a long half-life following oral administration of peptide drugs, can alter the distribution of peptides and may hold potential for tissue targeting. Due to the inherent safety and well-defined chemical nature of the fatty acids, this technology provides a versatile approach to peptide and protein drug discovery.

Analysis of Sheep and Goat IAPP Provides Insight into IAPP Amyloidogenicity and Cytotoxicity

Human islet amyloid polypeptide (hIAPP) plays a role in glucose regulation but forms pancreatic amyloid deposits in type 2 diabetes, and that process contributes to β-cell dysfunction. Not all species develop diabetes, and not all secrete an IAPP that is amyloidogenic in vitro under normal conditions, a perfect correlation currently exists between both. Studies of IAPPs from such organisms can provide clues about the high amyloidogenicity of hIAPP and can inform the design of soluble analogues of hIAPP. Sheep and goat IAPP are among the most divergent from hIAPP, with 13 and 11 substitutions, respectively, including an unusual Tyr to His substitution at the C-terminus. The properties of sheep and goat IAPP were examined in solution and in the presence of anionic vesicles, resulting in no observed amyloid formation, even at increased concentrations. Furthermore, both peptides are considerably less toxic to cultured β-cells than hIAPP. The effect of the Y37H replacements was studied in the context of hIAPP, as was a Y37R substitution. Buffer- and salt-dependent effects were observed. There was little impact on the time to form amyloid in phosphate-buffered saline; however, a significant deceleration was observed in Tris buffer, and amyloid formation was slower in the absence of added salt. The Y37H substitution had little impact on toxicity, while the Y37R replacement led to a 30% decrease in toxicity compared with that of hIAPP. The implications for the amyloidogenicity of hIAPP and the design of soluble analogues of the human peptide are discussed.

Targeting appetite and satiety in diabetes and obesity, via G protein-coupled receptors

Type 2 diabetes and obesity have reached pandemic proportions throughout the world, so much so that the World Health Organisation coined the term "Globesity" to help encapsulate the magnitude of the problem. G protein-coupled receptors (GPCRs) are highly tractable drug targets due to their wide involvement in all aspects of physiology and pathophysiology, indeed, GPCRs are the targets of approximately 30% of the currently approved drugs. GPCRs are also broadly involved in key physiologies that underlie type 2 diabetes and obesity including feeding reward, appetite and satiety, regulation of blood glucose levels, energy homeostasis and adipose function. Despite this, only two GPCRs are the target of approved pharmaceuticals for treatment of type 2 diabetes and obesity. In this review we discuss the role of these, and select other candidate GPCRs, involved in various facets of type 2 diabetic or obese pathophysiology, how they might be targeted and the potential reasons why pharmaceuticals against these targets have not progressed to clinical use. Finally, we provide a perspective on the current development pipeline of anti-obesity drugs that target GPCRs.

Anti-Obesity Medications and Investigational Agents: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This "Anti-Obesity Medications and Investigational Agents: An Obesity Medicine Association Clinical Practice Statement 2022" is intended to provide clinicians an overview of Food and Drug Administration (FDA) approved anti-obesity medications and investigational anti-obesity agents in development.

Methods

The scientific information for this Clinical Practice Statement (CPS) is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

This CPS describes pharmacokinetic principles applicable to those with obesity, and discusses the efficacy and safety of anti-obesity medications [e.g., phentermine, semaglutide, liraglutide, phentermine/topiramate, naltrexone/bupropion, and orlistat, as well as non-systemic superabsorbent oral hydrogel particles (which is technically classified as a medical device)]. Other medications discussed include setmelanotide, metreleptin, and lisdexamfetamine dimesylate. Data regarding the use of combination anti-obesity pharmacotherapy, as well as use of anti-obesity pharmacotherapy after bariatric surgery are limited; however, published data support such approaches. Finally, this CPS discusses investigational anti-obesity medications, with an emphasis on the mechanisms of action and summary of available clinical trial data regarding tirzepatide.

Conclusion

This "Anti-Obesity Medications and Investigational Agents: An Obesity Medicine Association Clinical Practice Statement 2022" is one of a series of OMA CPSs designed to assist clinicians in the care of patients with pre-obesity/obesity.

Preclinical evaluation of a protracted GLP-1/glucagon receptor co-agonist: Translational difficulties and pitfalls

During recent years combining GLP-1 and glucagon receptor agonism with the purpose of achieving superior weight loss and metabolic control compared to GLP-1 alone has received much attention. The superior efficacy has been shown by several in preclinical models but has been difficult to reproduce in humans. In this paper, we present the pre-clinical evaluation of NN1177, a long-acting GLP-1/glucagon receptor co-agonist previously tested in clinical trials. To further investigate the contribution from the respective receptors, two other co-agonists (NN1151, NN1359) with different GLP-1-to-glucagon receptor ratios were evaluated in parallel. In the process of characterizing NN1177, species differences and pitfalls in traditional pre-clinical evaluation methods were identified, highlighting the translational challenges in predicting the optimal receptor balance in humans. In diet-induced obese (DIO) mice, NN1177 induced a dose-dependent body weight loss, primarily due to loss of fat mass, and improvement in glucose tolerance. In DIO rats, NN1177 induced a comparable total body weight reduction, which was in contrast mainly caused by loss of lean mass, and glucose tolerance was impaired. Furthermore, despite long half-lives of the three co-agonists, glucose control during steady state was seen to depend on compound exposure at time of evaluation. When evaluated at higher compound exposure, glucose tolerance was similarly improved for all three co-agonists, independent of receptor balance. However, at lower compound exposure, glucose tolerance was gradually impaired with higher glucagon receptor preference. In addition, glucose tolerance was found to depend on study duration where the effect of glucagon on glucose control became more evident with time. To conclude, the pharmacodynamic effects at a given GLP-1-to-glucagon ratio differs between species, depends on compound exposure and study length, complicating the identification of an optimally balanced clinical candidate. The present findings could partly explain the low number of clinical successes for this dual agonism.

Linking hIAPP misfolding and aggregation with type 2 diabetes mellitus: a structural perspective

There are over 40 identified human disorders that involve certain proteins folding incorrectly, accumulating in the body causing damage to cells and organs and causing disease. Type 2 Diabetes Mellitus (T2DM) is one of these protein misfolding disorders (PMDs) and involves human islet amyloid polypeptide (hIAPP) misfolding and accumulating in parts of the body, primarily in the pancreas, causing damage to islet cells and affecting glucose regulation. In this review, we have summarised our current understanding of what causes hIAPP to misfold, what conformations are found in different parts of the body with a particular focus on what is known about the structure of hIAPP and how this links to T2DM. Understanding the molecular basis behind these misfolding events is essential for understanding the role of hIAPP to develop better therapeutics since type 2 diabetes currently affects over 4.9 million people in the United Kingdom alone and is predicted to increase as our population ages.