Introduction and Objective: Obesity trials are conducted in a competitive landscape with increasing protocol complexity. Phase I and II studies have distinct operational demands requiring phase-specific strategies. Methods: Review of 15 Phase I and II obesity studies conducted between 2020 and 2025 across North America and Europe informed phase specific best practices. Results: Phase I studies benefited from intensive oversight, in-house patient stays and early-phase units assessment expertise and body composition imaging. Standardized imaging workflows and structured patient training supported data integrity and timely decision-making. Phase II studies required patient retention focus to ensure data integrity. For all studies, participant compensation was the leading retention approach, though not consistently implemented, followed by transportation support and access to lifestyle counseling, which were utilized across all trials. Findings were consistent with a recent global site survey, which identified emerging tactics such as gym membership reimbursement. Post trial access to maintenance medication, while infrequently used in Phase II appeared a high value retention enabler. Conclusion: Obesity trial success depends on phase-appropriate operational design. Phase I trials benefit from imaging-ready early-phase units and intensive oversight, while Phase II studies require scalable, patient-centered support strategies to sustain retention and data integrity. Disclosure S. Patel: None. I. Eniu: None.
Patel et al. (Fri,) studied this question.