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Less than half of US clinical trials report results on on time

Hourglass and calendar

In 2007, the US Food and Drug Administration Amendments Act (FDAAA) Final Rule mandated that results of clinical trials are reported on within one year of trial completion. A study into Trials Transparency from the Ben Goldacre EBM DataLab at the University of Oxford has found that less than half of sponsors are meeting this deadline.

In an article published in The Lancet, the authors present reporting timelines for applicable studies, based on data collected from between March 2018 and September 2019. Of the 4209 trials due to report results (excluding those with a certificate of extension), 40.9% did so within the one-year time-frame. This rose to 63.8% when results reported after one year were included, leaving over a third of studies unreported. The median time from study completion to data reporting was 424 days, representing a delay of 59 days beyond the mandated requirement of one year.

Encouragingly for pharmaceutical companies, industry sponsors were significantly more likely to report results on time than non-industry sponsors (50% vs 34%; odds ratio 3.08 [2.52–3.77]). Of note, results were reported within one year for just 31% of trials sponsored by the US Government. Sponsors who had registered a large number of trials, were more likely to report results, and more likely to report results on time, compared with sponsors who had few trials registered. Of the 13 biggest sponsors, each with more than 30 due trials, six were pharmaceutical companies, who all achieved more than 92% compliance. Similarly, there was high compliance among pharmaceutical companies sponsoring 10 or more due trials, with many reporting 100% compliance.

Non-reporting of clinical trial data is a public concern as it erodes the evidence base for medical decision-making, as highlighted by the AllTrials campaign. This study shows that while some industry sponsors are leading the way, the timely release of all clinical trial data is still yet to be attained. The study authors suggest that the overall lack of compliance is likely to reflect a lack of enforcement by regulators: to their knowledge no fines have been imposed by the FDA to date.

Given the lack of effective enforcement by regulators, the study authors are maintaining a public registry of compliance data for individual sponsors at, relying on public accountability to put pressure on those who continue to fall short on clinical trial results reporting.


Summary by Julianna Solomons PhD, CMPP from Aspire Scientific


With thanks to our sponsors, Aspire Scientific Ltd and NetworkPharma Ltd

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