biostudies-literatureDoshi PFDA HHSLaura and John Arnold Foundation213-219https://www.ebi.ac.uk/biostudies/studies/S-EPMC7691700biostudies-literatureUnknown25(6)<h4>Purpose</h4>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.<h4>Methods</h4>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 BMJ evidence-based medicineAdjuvant-containing control arms in pivotal quadrivalent human papillomavirus vaccine trials: restoration of previously unpublished methodology.PMC7691700U01 FD005946Jones MBourgeois FSpence OHong KJefferson TLee HDoshi PShamseer LfalseAdjuvant-containing control arms in pivotal quadrivalent human papillomavirus vaccine trials: restoration of previously unpublished methodology.<h4>Purpose</h4>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.<h4>Methods</h4>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 2020-01-01T00:00:00Z2020 Dec2025-04-21T17:50:19.869Z2021-02-20T09:58:44ZS-EPMC76917003218427710.1136/bmjebm-2019-111331