Background: Glucagon-like peptide-1 (GLP-1) receptor agonists are a key pharmacological target in obesity management, associated with sustained weight loss and broader metabolic benefits beyond glycaemic control. Objective: To analyse the characteristics, design trends, and research themes of completed clinical trials investigating GLP-1-based interventions for obesity registered in ClinicalTrials.gov. Methods: A registry-based cross-sectional qualitative analysis was conducted using ClinicalTrials.gov data retrieved on October 18, 2025. Completed interventional trials evaluating GLP-1 receptor agonists, including liraglutide, semaglutide, tirzepatide, exenatide, dulaglutide, and lixisenatide, were identified. Extracted variables included study phase, intervention type, enrolment, primary outcomes, and completion year. Descriptive statistics were used to summarize quantitative data, and qualitative thematic synthesis was applied to categorize outcome domains and research focus. Results: A total of 227 completed interventional studies were identified. Liraglutide was the most frequently investigated agent (n = 86), followed by semaglutide (n = 18), tirzepatide (n = 18), exenatide (n = 15), and other GLP-1 analogues. Phase 3 and 4 trials predominated, with most studies enrolling fewer than 200 participants. Primary outcomes were mainly weight-related, with increasing attention to hepatic, cardiometabolic, and inflammatory endpoints. A marked rise in completed trials was observed after 2018, corresponding with the introduction of newer GLP-1 analogues. Conclusion: Completed GLP-1 obesity trials demonstrate an expanding research focus from weight and glycaemic control toward broader metabolic and organ-specific outcomes. This registry-based qualitative analysis provides a novel overview of research maturity and evolving priorities in GLP-1–based obesity pharmacotherapy. Keywords: glucagon-like peptide-1, obesity, liraglutide, semaglutide, tirzepatide, metabolic outcomes
Alourfi et al. (2026) studied this question.