Abstract
Background Non-publication, incomplete publication and excessively slow publication of clinical trial outcomes contribute to research waste and can harm patients. While research waste in German academic trials is well documented, research waste in Germany related to a specific disease area across non-commercial and commercial sponsors has not previously been assessed. Methods In this cohort study, we used public records from three clinical trial registries to identify 70 completed or terminated clinical trials involving women with metastatic breast cancer with trial sites in Germany. We then searched registries and the literature for trial outcomes and contacted sponsors about unreported studies. Results We found that 66/70 trials (94.3%) had made their results public. Only 13/70 (18.6%) trials had reported results within one year of completion as recommended by the World Health Organisation (WHO). The outcomes of 4/70 trials (5.7%) had not been made public at all, but only one of those trials had recruited a significant number of patients. Conclusions Discussions about research waste in clinical trials commonly focus on weakly designed or unreported trials. We believe that late reporting of results is another important form of research waste. In addition, a discussion regarding the appropriate ethical and legal rules for reporting the results of terminated trials might add value. German legislation now requires sponsors to upload the results of some clinical trials onto a trial registry within one year of trial completion, but these laws only cover around half of all trials. Our findings highlight the potential benefits of extending the scope of national legislation to cover all interventional clinical trials involving German patients.