Structural analysis of the dual agonism at GLP-1R and GCGR

Glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR), two members of class B1 G protein-coupled receptors, play important roles in glucose homeostasis and energy metabolism. They share a high degree of sequence homology but have different functionalities. Unimolecular dual agonists of both receptors developed recently displayed better clinical efficacies than that of monotherapy. To study the underlying molecular mechanisms, we determined high-resolution cryo-electron microscopy structures of GLP-1R or GCGR in complex with heterotrimeric Gs protein and three GLP-1R/GCGR dual agonists including peptide 15, MEDI0382 (cotadutide) and SAR425899 with variable activating profiles at GLP-1R versus GCGR. Compared with related structures reported previously and supported by our published pharmacological data, key residues responsible for ligand recognition and dual agonism were identified. Analyses of peptide conformational features revealed a difference in side chain orientations within the first three residues, indicating that distinct engagements in the deep binding pocket are required to achieve receptor selectivity. The middle region recognizes extracellular loop 1 (ECL1), ECL2, and the top of transmembrane helix 1 (TM1) resulting in specific conformational changes of both ligand and receptor, especially the dual agonists reshaped ECL1 conformation of GLP-1R relative to that of GCGR, suggesting an important role of ECL1 interaction in executing dual agonism. Structural investigation of lipid modification showed a better interaction between lipid moiety of MEDI0382 and TM1-TM2 cleft, in line with its increased potency at GCGR than SAR425899. Together, the results provide insightful information for the design and development of improved therapeutics targeting these two receptors simultaneously.

Perspectives In Weight Control In Diabetes - Sglt2 Inhibitors And Glp-1-Glucagon Dual Agonism

Treatment of people with type 2 diabetes mellitus (T2D) and obesity should include glycemic control and sustained weight loss. However, organ protection and/or risk reduction for co-morbidities have also emerged as important goals. Here, we define this combined treatment approach as 'weight loss plus' and describe it as a metabolic concept where increased energy expenditure is central to outcomes. We suggest there are currently two drug classes - sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 (GLP-1)-glucagon dual agonists - that can facilitate this 'weight loss plus' approach. We describe evidence supporting that both classes address the underlying pathophysiology of T2D and facilitate normalization of metabolism through increased periods of energy expenditure, which effect other organ systems and may facilitate long-term cardio-renal benefits. These benefits have been demonstrated in trials of SGLT2is, and appear, to some degree, to be independent of glycemia and substantial weight loss. The combined effect of caloric restriction and metabolic correction facilitated by SGLT2i and GLP-1-glucagon dual agonists can be conceptualized as mimicking dietary restriction and physical activity, a phenomenon not previously observed with drugs whose benefits predominantly arise from absolute weight loss, and which may be key to achieving a 'weight loss plus' approach to treatment.

Phase I studies of the safety, tolerability, pharmacokinetics and pharmacodynamics of the dual glucagon receptor/glucagon-like peptide-1 receptor agonist BI 456906

AIM

To report two phase I studies of the novel subcutaneous glucagon-like peptide-1 receptor/glucagon receptor (GLP-1R/GCGR) dual agonist BI 456906 versus placebo in healthy volunteers and people with overweight/obesity.

MATERIALS AND METHODS

A phase Ia study (NCT03175211) investigated single rising doses (SRDs) of BI 456906 in 24 males with a body mass index (BMI) of 20-<30 kg/m² . A phase Ib study (NCT03591718) investigated multiple rising doses (MRDs) of BI 456906 (escalated over 6 [Part A] or 16 [Part B] weeks) in 125 adults with a BMI of 27-40 kg/m² .

RESULTS

In the SRD study (N = 24), mean body weight decreased with increasing BI 456906 dose. In the MRD study, the maximum decreases in placebo-corrected mean body weight were at week 6 (-5.79%, dosage schedule [DS] 1; Part A) and week 16 (-13.8%, DS7; Part B). BI 456906 reduced plasma amino acids and glucagon, indicating target engagement at GCGRs and GLP-1Rs. Drug-related adverse events (AEs) increased with BI 456906 dose. The most frequent drug-related AE with SRDs was decreased appetite (n = 9, 50.0%), and two subjects (8.3%) did not complete the trial because of AEs (nausea and vomiting). During MRD Part A (N = 80), 10 subjects (12.5%) discontinued BI 456906, most commonly because of a cardiac or vascular AE (n = 6, 7.5%); during Part B (N = 45), eight subjects (17.8%) discontinued BI 456906, mainly because of AEs (n = 6, 13.3%), most commonly gastrointestinal disorders.

CONCLUSIONS

BI 456906 produced a placebo-corrected body weight loss of 13.8% (week 16), highlighting its potential to promote clinically meaningful body weight loss in people with overweight/obesity.

GLP-1 receptor agonists for the treatment of obesity: Role as a promising approach

Obesity is a complex disease characterized by excessive fat accumulation which is caused by genetic, environmental and other factors. In recent years, there has been an increase in the morbidity, disability rate,and mortality due to obesity, making it great threat to people's health and lives, and increasing public health care expenses. Evidence from previous studies show that weight loss can significantly reduce the risk of obesity-related complications and chronic diseases. Diet control, moderate exercise, behavior modification programs, bariatric surgery and prescription drug treatment are the major interventions used to help people lose weight. Among them, anti-obesity drugs have high compliance rates and cause noticeable short-term effects in reducing obese levels. However, given the safety or effectiveness concerns of anti-obesity drugs, many of the currently used drugs have limited clinical use. Glucagon-like peptide-1 receptor (GLP-1R) agonists are a group of drugs that targets incretin hormone action, and its receptors are widely distributed in nerves, islets, heart, lung, skin, and other organs. Several animal experiments and clinical trials have demonstrated that GLP-1R agonists are more effective in treating or preventing obesity. Therefore, GLP-1R agonists are promising agents for the treatment of obese individuals. This review describes evidence from previous research on the effects of GLP-1R agonists on obesity. We anticipate that this review will generate data that will help biomedical researchers or clinical workers develop obesity treatments based on GLP-1R agonists.