The insufficient publication of early-phase clinical trials in oncology.

INTRODUCTION: Early-phase oncology clinical trials are often underrepresented in studies regarding publication of trial results. This study investigated the publication status of early-phase clinical trials, focusing on trials of compounds discontinued in clinical development. METHODS: Two retrospective cohorts were formed: one included early-phase trials supporting European Medicines Agency marketing authorization applications (2017-2020), while the second cohort included early-phase trials of discontinued compounds. Trials were matched with database registry and their corresponding publications. RESULTS: The first cohort consisted of 73 trials. Nine ongoing trials were excluded. No full publication or full report was found for 11% (n = 7/64) of trials. Median time from registered closure date to publication of trial results as full publication or full report was 109 days [IQR -733-597]. Trials sponsored by large size firms (HR 2.25 [95%CI 1.23-4.1]), with >100 patients (HR 2.15 [95%CI 1.19-3.88]) and duration >2 years (HR 6.83 [95%CI 3.03-14.38]) were more likely to be published. The cohort with discontinued compounds consisted of 66 clinical trials. After exclusion of nine ongoing trials, 39% (n = 22/57) lacked full publication or full report. Median time from registered closure date to publication of trial results as full publication or full report was 702 days [IQR 263-2200]. No covariates influencing publication status were found. CONCLUSIONS: Timely and complete publication of early-phase clinical trial results remains inadequate. Forty percent of trials with discontinued drugs are not publicly reported, and even among approved compounds, 11% of early-phase trial results cannot be found in the public domain.