Phase IV Drug Trials With a Canadian Site: A Comparison of Industry-Funded and Non-Industry-Funded Trials.

Recent regulatory reforms have favored expedited drug marketing and increased reliance on Phase IV clinical trials for safety and efficacy assurance. This study, utilizing ClinicalTrials.gov, assesses the characteristics of Phase IV trials, with at least one site in Canada, examining those funded by industry sponsors and those lacking industry funding. Additionally, it compares the publication status of industry-funded and non-industry-funded trials through a manual review of the medical literature. Between 2000 and 2022, 864 Phase IV trials were completed, with 480 (55.6%) receiving industry funding and 384 (44.4%) funded solely by non-industry sources. Industry-funded clinical trials were larger (mean 204 enrollees versus 70), more likely to be international (57.7% versus 9.6%) and reported results more promptly (1.21 years after completion versus 1.85 years), yet both types shared similar designs, outcomes, and completion times. Publication rates were 81.8% for industry-funded and 65.8% for non-industry-funded trials. The ClinicalTrials. gov registry displayed 48 inaccuracies in publication associations, raising concerns about its accuracy. Our findings underscore the existing institutional limitations in ensuring comprehensive reporting and publication of Phase IV trial results funded by both industry and non-industry sources.