Posting of clinical trial results and other critical information from completed medicines trials on ClinicalTrials.gov.

Abstract

Clinical trials transparency requires trial registration and the posting of results on a public register. US regulations also require the posting of protocols and statistical analysis plans (SAPs). For US Federal agency funded trials to be started on or after 21January2019, informed consent forms (ICFs) must also be posted. Posting these documents is not mandatory in other countries. We aimed to assess compliance with US regulations of trials conducted in the US or in other countries with respect to ICFs, protocols, SAPs, and results. This cross-sectional analysis (27April2023) comprised completed medicines trials to be started on or after 21January2019 registered on ClinicalTrials.gov. Trial data were registered by funder type (i.e., 'US federal agencies', industry, and 'all others') and development phase. Of 5,584 trials, 40% were conducted solely in the US. 47% and 12% of US and non-US trials had posted results. Some 40% of US trials had posted protocols and SAPs as did 9% of trials conducted in other countries. Only 10% (US) and 2% (other countries) of trials had posted ICFs. When the margin of the last 2 and 12 months after primary completion date were considered in the analysis, ICF posting rate did not change, but posting results increased to 64% for US trials. 'US Federal agencies' funded trials were significantly more likely to post ICFs than industry [OR 23.9 (12.5-45.7; <.001)] or 'all others' [OR 3.16 (1.79-5.56; <.001)]. Future interventions should be considered to encourage timely posting of trial results and information.