Results
A total of 1877 trials were identified on ClinicalTrials.gov. We identified 789 trials involving therapeutic interventions, with 755 of those trials reporting a PEP in a published article. One trial had a PEP change detected prior to trial initiation and was not included as having a PEP change in the present study. Of 755 trials meeting the inclusion criteria, 145 (19.2%) had detectable PEP changes occurring after the study start date by at least 1 of the 3 detection methods (ClinicalTrials.gov, article, published protocols) (