RT Journal Article SR Electronic T1 Adjuvant-containing control arms in pivotal quadrivalent human papillomavirus vaccine trials: restoration of previously unpublished methodology JF BMJ Evidence-Based Medicine JO BMJ EBM FD BMJ Publishing Group Ltd SP bmjebm-2019-111331 DO 10.1136/bmjebm-2019-111331 A1 Peter Doshi A1 Florence Bourgeois A1 Kyungwan Hong A1 Mark Jones A1 Haeyoung Lee A1 Larissa Shamseer A1 O'Mareen Spence A1 Tom Jefferson YR 2020 UL http://ebm.bmj.com/content/early/2020/03/17/bmjebm-2019-111331.abstract AB Purpose Trustworthy reporting of quadrivalent human papillomavirus (HPV) vaccine trials is the foundation for assessing the vaccine’s risks and benefits. However, several pivotal trial publications incompletely reported important methodological details and inaccurately described the formulation that the control arms received. Under the Restoring Invisible and Abandoned Trials initiative (RIAT), we aim to restore the public record regarding the content and rationale of the controls used in the trials.Methods We assembled a cohort (five randomised controlled trials) described as placebo-controlled using clinical study reports (CSRs) obtained from the European Medicines Agency. We extracted the content and rationale for the choice of control used in each trial across six data sources: trial publications, register records, CSR synopses, CSR main bodies, protocols and informed consent forms.Results Across data sources, the control was inconsistently reported as ‘placebo’-containing aluminium adjuvant (sometimes with dose information). Amorphous aluminium hydroxyphosphate sulfate (AAHS) was not mentioned in any trial registry entry, but was mentioned in all publications and CSRs. In three of five trials, consent forms described the control as an ‘inactive’ substance. No rationale for the selection of the control was reported in any trial publication, register, consent form, CSR synopsis or protocol. Three trials reported the rationale for choice of control in CSRs: to preserve blinding and assess the safety of HPV virus-like particles as the ‘safety profile of (AAHS) is well characterised’.Conclusions The stated rationale of using AAHS control—to characterise the safety of the HPV virus-like particles—lacks clinical relevance. A non-placebo control may have obscured an accurate assessment of safety and the participant consent process of some trials raises ethical concerns.Trial registration numbers NCT00092482, NCT00092521, NCT00092534, NCT00090220, NCT00090285.