Footnotes

• Contributors LC designed the study, collated the FCOI information, reviewed and drafted the summary of the data on clinicaltrials.gov and developed a first draft of the paper (excluding the last two sections). AFS reviewed the FCOI information, reviewed and assisted with the summary of the clinical trials.gov data and made significant contributions to succeeding drafts of the final paper. TS drafted the last two sections and made substantial contributions to succeeding drafts of the final paper.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.