The promise of glucagon-like peptide 1 receptor agonists (GLP-1RA) for the treatment of obesity: a look at phase 2 and 3 pipelines

Introduction: GLP-1-based therapies have changed the treatment of overweight/obesity. Liraglutide 3.0 mg daily, the first GLP-1 RA approved for treatment of overweight, induced a weight loss of 6–8%, Semaglutide 2.4 mg once weekly improved weight loss to about 12–15%, while the dual GIP/GLP-1 receptor agonist tirzepatide once weekly has induced a weight loss of about 20% in obese people without diabetes. Areas covered: This review describes results obtained with GLP-1 mono-agonists, GLP-1/GIP dual agonists, GLP-1/glucagon co-agonists, and the triple agonist retatrutide (GIP/GLP-1/glucagon), which have shown beneficial effect both on body weight and steatotic liver disease. A combination of semaglutide (a GLP-1 agonist) and cagrilintide (a long-acting amylin analogue) for weekly administration is currently in phase III development, and so is oral semaglutide and several non-peptide small molecule GLP-1 agonists for oral administration. The adverse events with the GLP-1-based therapies are primarily gastrointestinal and include nausea, vomiting, obstipation, or diarrhea, which often can be mitigated by slow up titration. Expert opinion: The GLP-1-based therapies will change the treatment of obesity and its comorbidities including steatotic liver disease in the future. Outstanding question is maintenance of the weight loss, possibly pharmacological treatment needs to be life-long.