Scarce quality assurance documentation in major clinical trial registries for approved medicines used in post-marketing clinical trials.

This study demonstrates that none of the CTRs of ICMJE and WHO platforms has adequate fields to establish that the source of post-marketing IMPs is of assured quality. This is astonishing given the lengthy requirements in WHO and ICMJE guidelines. Considering the relation between IMP quality and safety of clinical trial participants, the gap of quality assurance fields should be bridged at CTRs concurrently to adjustments of WHO and ICMJE guidelines on CTRs. Specifically, IMP quality testing addressing issues on IMP appearance, impurities, microbial contamination, and dosing should be conducted and reported before, during, and after clinical trial conduct. Until adoption of these measures, the EU CTR should be preferred for registration of phase IV clinical trials conducted in countries lacking stringent regulatory capacities.