Clinical innovation and scientific progress in GLP-1 medicine
Series edited by Daniel J. Drucker
Therapies targeting the glucagon-like peptide 1 (GLP-1) receptor have revolutionized the treatment of obesity and diabetes. This series of reviews, curated by Dr. Dan Drucker, describes the latest research in this fast-moving in field, from our evolving understanding of the mechanism of GLP-1 receptor signaling to the medicines’ impact on inflammation and the consequences for heart, kidney, and brain health. The reviews also explore the impact of these medicines on conditions beyond their initial indications, including cancer and neurodegenerative disease risk.
Articles in series
Abstract
GLP-1 receptor agonist (GLP-1RA) medications have transformed the treatment of type 2 diabetes (T2D) and obesity, with robust evidence for cardiovascular and renal benefits. Nevertheless, GLP-1RA therapy is associated with a pattern of adverse events affecting their safety and tolerability. Here, we delineate mechanisms potentially leading to adverse responses to GLP-1RAs, describe the impact of side effects on treatment persistence, discuss potential mitigation strategies, and identify areas requiring further studies. Concerns that GLP-1RAs raise the risk for acute pancreatitis and pancreatic cancer have been dispelled by long-term clinical trials. However, GLP-1RAs may confer an increased risk for thyroid cancer. Sight-threatening eye complications resulting from rapid reductions in glycemia may be avoided by retinal screening and ophthalmologic treatment before GLP-1RA initiation. The slowing of gastric emptying with GLP-1RA treatment increases the propensity for retained gastric contents, which could increase the risk of aspiration during upper gastrointestinal endoscopy or general anesthesia. These risks may, however, be elevated in individuals with long-standing T2D even in the absence of GLP-1RA treatment. Improved pharmacovigilance and a more standardized, quantitative assessment of adverse events in clinical trials, particularly in the assessment of gastrointestinal symptoms, would facilitate definition of the benefit-risk relationship for individual medications and indications.
Authors
Ryan J. Jalleh, Nicholas J. Talley, Michael Horowitz, Michael A. Nauck
Abstract
Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have become an essential drug class for treating type 2 diabetes, offering proven benefits in glycemic control, weight reduction, and cardiovascular and renal protection. However, growing evidence of heterogeneity in GLP-1RA treatment effects highlights the potential for developing precision medicine approaches to more accurately allocate GLP-1RAs to maximize patient benefit. In this Review, we explore the evidence for treatment effect heterogeneity with GLP-1RAs, focusing on clinical and genetic factors that robustly influence established therapeutic outcomes. We also highlight the potential of recent predictive models that integrate routine clinical data with personalize treatment decisions, comparing GLP-1RA to other major type 2 diabetes drug classes. While such models have shown considerable promise in identifying optimal type 2 diabetes treatment based on glycemic response, their utility for informing treatment choice for other clinical outcomes remains largely unexplored.
Authors
Pedro Cardoso, John M. Dennis, Ewan R. Pearson
Abstract
Cancer diagnoses are prevalent in people with obesity and type 2 diabetes, and abundant clinical evidence supports the protective effects of weight loss for cancer prevention. Glucagon-like peptide-1 (GLP-1) receptor agonists have revolutionized obesity and type 2 diabetes medicine and alleviate many comorbidities of these metabolic diseases. In this Review, we summarize the current clinical evidence for GLP-1 receptor agonists and cancer risk, including thyroid, pancreatic, gastrointestinal, and hormone-dependent malignancies. With few exceptions, recent meta-analyses report that GLP-1 receptor therapies do not increase cancer incidence and may lower risk in some cases. Preclinical studies reinforce the anticancer effects of GLP-1 receptor therapies, even in non-obese models. However, there are still many opportunities for translational insight as the field grows. Immune-modulating effects of GLP-1 receptor agonists are reported in several preclinical cancer studies, which may reflect direct action on immune cells or result from improved metabolic function. We highlight ongoing clinical trials for GLP-1 receptor therapies in cancer patients, and offer considerations for preclinical studies, including perspectives on the timing and duration of GLP-1 receptor agonist treatment, concurrent use of standard anticancer therapies, and interpretation of models of cancer risk versus progression.
Authors
Estefania Valencia-Rincón, Rajani Rai, Vishal Chandra, Elizabeth A. Wellberg
Abstract
Historically, antiobesity medications have been modestly effective at best, with side-effect profiles that limit compliance and often preclude the long-term therapy required to maintain weight loss. Recently developed therapies based on analogs of the gut hormone glucagon-like peptide-1 (GLP-1) have transformed the medical management of obesity, leading both to a degree of weight loss that rivals bariatric surgery and a reduction in morbidity and mortality associated with obesity-related complications. GLP-1 receptor agonist (GLP-1RA) therapies were developed to mimic the peripheral effects of GLP-1, but it is now well established that their efficacy in the treatment of obesity depends on reducing energy intake through their action in the central nervous system (CNS). Recent data indicate that the aversive gastrointestinal side effects of GLP-1RAs are also CNS mediated. Although a complete understanding of the neural circuits underlying GLP-1RA–induced weight loss remains elusive, a great deal has been learned in recent years. This Review summarizes proposed gut-brain and central mechanisms through which GLP-1 and its synthetic analogs regulate food intake and bodyweight.
Authors
Lisa R. Beutler
Abstract
Glucagon-like peptide-1 receptor agonists (GLP-1RAs), established therapies for type 2 diabetes and obesity, are increasingly recognized for their potential in neurodegenerative diseases. Preclinical studies across diverse neurodegenerative conditions consistently demonstrate neuroprotective effects of GLP-1RAs, including reduced protein aggregation, enhanced autophagy, improved mitochondrial function, suppression of neuroinflammation, and preservation of synaptic integrity. Epidemiological analyses further suggest reduced incidence of dementia, Parkinson disease, and multiple sclerosis among long-term GLP-1RA users. Early human trials provide signals of target engagement, such as preserved cerebral glucose metabolism, altered inflammatory biomarkers, and slowed brain atrophy, although clinical outcomes to date remain mixed and trials in rarer disorders are sparse. Translation is constrained by uncertainty around optimal molecule choice, CNS penetrance, tolerability, adherence, and heterogeneity of response. Furthermore, next-generation dual and triple agonists may offer enhanced efficacy but remain untested in neurodegeneration. Conceptually, GLP-1RAs share pleiotropic effects with exercise — one of the few interventions with proven disease-modifying potential — by enhancing insulin signaling, stabilizing mitochondria, reducing inflammation, and promoting synaptic plasticity. This overlap highlights their promise as “pharmacological analogues of exercise,” and underscores the need for biomarker-driven, disease-specific trials to establish whether GLP-1RAs can deliver durable disease modification across the spectrum of neurodegenerative diseases.
Authors
Dilan Athauda, Nigel H. Greig, Wassilios G. Meissner, Thomas Foltynie, Sonia Gandhi
Abstract
The incretin hormone glucagon-like peptide-1 (GLP-1) exerts potent effects on glucose metabolism, prompting the development of therapeutic strategies that enhance activity of the GLP-1 receptor (GLP-1R) pathway. Inhibitors of dipeptidyl peptidase 4 (DPP-4) prolong the half-life of endogenous GLP-1 and typically achieve reductions in HbA1c of 0.5%–0.8%. However, large-scale cardiovascular (CV) outcomes trials (CVOTs) with DPP-4 inhibitors demonstrated CV safety but did not show a reduction in CV events. A second incretin-based therapeutic approach was the development of GLP-1R agonists (GLP-1RAs). Various GLP-1RAs, including liraglutide, semaglutide, and dulaglutide, demonstrated a reduction in CV outcomes in large CVOTs. Initially, these medications were only available as injectable agents for subcutaneous administration, but recent technological advancements have enabled the development of orally available GLP-1RAs. A third incretin-based approach is tirzepatide, a dual agonist of GLP-1R and glucose-dependent insulinotropic polypeptide receptor (GIPR), which achieves greater HbA1c reduction and weight loss compared with GLP-1RAs alone. Ongoing large-scale CVOTs will determine its effects on hard cardiovascular endpoints. This Review summarizes the effects of GLP-1 and GLP-1RAs in the CV system as well as clinical data of GLP-1RAs in individuals with CV disease or high CV risk.
Authors
Florian Kahles, Andreas L. Birkenfeld, Nikolaus Marx
Abstract
Glucagon-like peptide-1 (GLP-1) was initially considered to be a hormone with a predominant role in regulating glucose metabolism by inducing insulin secretion, reducing glucagon secretion, and ameliorating insulin resistance, with the last effect being largely dependent on the induction of weight loss. In more recent years, the role of this peptide beyond metabolism has progressively been explored, including its impact on kidney physiology and kidney clinical outcomes in people with obesity with or without diabetes. Indeed, despite only modest expression of the GLP-1 receptor in the kidney, the renoprotective actions of GLP-1 and its receptor agonists have become an area of intensive investigation. This Review appraises the current status of GLP-1 peptide and its receptor agonists and focuses on the preclinical as well as recent seminal clinical findings defining the kidney benefits conferred by GLP-1 receptor agonist treatment in people living with type 2 diabetes and obesity.
Authors
Mark E. Cooper, Daniël H. van Raalte
Abstract
Therapies based on glucagon-like peptide-1 (GLP-1) reduce rates of cardiovascular and chronic kidney disease in people with type 2 diabetes and/or obesity, with ongoing clinical trials investigating their effects in people with metabolic liver disease, arthritis, and both substance use and neurodegenerative disorders. Acute and chronic activation of GLP-1 receptor signaling also reduces systemic and tissue inflammation in mice and humans, through weight loss–dependent and –independent mechanisms, actions that may contribute to the expanding spectrum of clinical benefits ascribed to GLP-1 medicines. In this Review, we highlight current understanding of the direct and indirect antiinflammatory effects and mechanisms of GLP-1 medicines in both preclinical and clinical studies, covering emerging concepts, clinical relevance, and areas of uncertainty that require further investigation.
Authors
Chi Kin Wong, Daniel J. Drucker
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) is a class B1 G protein–coupled receptor and major therapeutic target in type 2 diabetes and obesity. Beyond its canonical role in Gαs/cAMP signaling, GLP-1R is increasingly recognized as an organizer of spatiotemporally defined signaling nanodomains, or “signalosomes.” This Review highlights our current knowledge on the mechanisms of assembly and regulation of GLP-1R signalosomes, including the involvement of biomolecular condensates formed by liquid-liquid phase separation, and the role of membrane contact sites between the endoplasmic reticulum (ER) and other organelles as key locations for GLP-1R signaling assemblies. Furthermore, we discuss existing data on the molecular composition and functional impact of two predicted GLP-1R nanodomains, one at ER–plasma membrane contact sites, where GLP-1R might interact with ion channels and transporters to influence local excitability and coordinated insulin secretion, and another at ER–mitochondria membrane contact sites, with the capacity to control lipid and calcium signaling and modulate ER and/or mitochondrial activity. We additionally discuss the role of GLP-1R posttranslational modifications as critical modulators of GLP-1R signal specification and nanodomain organization. Conceptualizing GLP-1R as a dynamic architect of spatiotemporally encoded signalosomes opens new avenues for a deeper understanding of incretin biology with the potential for identification of novel GLP-1R effectors and the development of refined therapeutic strategies for metabolic disease.
Authors
Gregory Austin, Alejandra Tomas
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)