The International Committee of Medical Journal Editors
(ICMJE) believes that there is an ethical obligation to responsibly
share data generated by interventional clinical
trials because participants have put themselves at risk.
In a growing consensus, many funders around the world
– foundations, government agencies, and industry – now
mandate data sharing. Here we outline ICMJE’s proposed
requirements to help meet this obligation. We encourage
feedback on the proposed requirements. Anyone
can provide feedback at www.icmje.org by 18 April
The ICMJE defines a clinical trial as any research
project that prospectively assigns people or a group of
people to an intervention, with or without concurrent
comparison or control groups, to study the cause-andeffect
relationship between a health-related intervention
and a health outcome. Further details may be found
in the Recommendations for the Conduct, Reporting,
Editing and Publication of Scholarly Work in Medical
Journals at www.icmje.org.
As a condition of consideration for publication of a
clinical trial report in our member journals, the ICMJE
proposes to require authors to share with others the
deidentified individual-patient data (IPD) underlying the
results presented in the article (including tables, figures,
and appendices or supplementary material) no later
than six months after publication. The data underlying
the results are defined as the IPD required to reproduce
the article’s findings, including necessary metadata. This
requirement will go into effect for clinical trials that begin
to enroll participants beginning one year after the
ICMJE adopts its data-sharing requirements*.
Enabling responsible data sharing is a major endeavor
that will affect the fabric of how clinical trials are
planned and conducted and how their data are used. By
changing the requirements of the manuscripts we will
consider for publication in our journals, editors can help
foster this endeavor. As editors, our direct influence is
logically, and practically, limited to those data underpinning
the results and analyses we publish in our journals.
The ICMJE also proposes to require that authors include
a plan for data sharing as a component of clinical
trial registration. This plan must include where the researchers
will house the data and, if not in a public repository,
the mechanism by which they will provide
others access to the data, as well as other data-sharing
plan elements outlined in the 2015 Institute of Medicine
report (e.g., whether data will be freely available to anyone
upon request or only after application to and approval
by a learned intermediary, whether a data use
agreement will be required) . ClinicalTrials.gov has
added an element to its registration platform to collect
data-sharing plans. We encourage other trial registries
to similarly incorporate mechanisms for the registration
of data-sharing plans. Trialists who want to publish in
ICMJE member journals (or nonmember journals that
choose to follow these recommendations) should
choose a registry that includes a data-sharing plan element
as a specified registry item or allows for its entry as
a free-text statement in a miscellaneous registry field. As
a condition of consideration for publication in our member
journals, authors will be required to include a description
of the data-sharing plan in the submitted
Authors may choose to share the deidentified
IPD underlying the results presented in the article
under less restrictive, but not more restrictive, conditions
than were indicated in the registered data-sharing
ICMJE already requires the prospective registration
of all clinical trials prior to enrollment of the first participant.
This requirement aims, in part, to prevent selective
publication and selective reporting of research outcomes,
and to prevent unnecessary duplication of
research effort. Including a commitment to a data-sharing
plan is a logical addition to trial registration that will
further each of these goals. Prospective trial registration
currently includes documenting the planned primary
and major secondary end points to be assessed, which
enables identification of incomplete reporting as well as
post hoc analyses. Declaring the plan for sharing data
prior to their collection will further enhance transparency
in the conduct and reporting of clinical trials by exposing
when data availability following trial completion
differs from prior commitments.
Sharing clinical trial data, including deidentified IPD,
requires planning to ensure appropriate ethics committee or institutional review board approval and the informed
consent of study participants. Accordingly, we
will defer these requirements for one year to allow investigators,
trial sponsors, and regulatory bodies time to
plan for their implementation.
Just as the confidentiality of trial participants must
be protected (through the deidentification of IPD), and
the needs of those reasonably requesting data met
(through the provision of useable data), the reasonable
rights of investigators and trial sponsors must also be
protected. ICMJE proposes the following to safeguard
these rights. First, ICMJE editors will not consider the
deposition of data in a registry to constitute prior publication.
Second, authors of secondary analyses using
these shared data must attest that their use was in accordance
with the terms (if any) agreed to upon their receipt.
Third, they must reference the source of the data
using a unique identifier of a clinical trial’s data set to
provide appropriate credit to those who generated it
and allow searching for the studies it has supported.
Fourth, authors of secondary analyses must explain
completely how theirs differ from previous analyses.
In addition, those who generate and then share clinical
trial data sets deserve substantial credit for their efforts.
Those using data collected by others should seek collaboration
with those who collected the data. However,
because collaboration will not always be possible, practical,
or desired, an alternative means of providing appropriate
credit needs to be developed and recognized
in the academic community. We welcome ideas about
how to provide such credit.
Data sharing is a shared responsibility. Editors of individual
journals can help foster data sharing by changing
the requirements of the manuscripts they will consider
for publication in their journals. Funders and
sponsors of clinical trials are in a position to support and
ensure adherence to IPD sharing obligations. If journal
editors become aware that IPD sharing obligations are
not being met, they may choose to request additional
information; to publish an expression of concern; to notify
the sponsors, funders, or institutions; or in certain
cases, to retract the publication.
In the rare situation in which compliance with these
requirements is impossible, editors may consider authors’
requests for exceptions. If an exception is made,
the reason(s) must be explained in the publication.
Sharing data will increase confidence and trust in
the conclusions drawn from clinical trials. It will enable
the independent confirmation of results, an essential
tenet of the scientific process. It will foster the development
and testing of new hypotheses. Done well, sharing
clinical trial data should also make progress more efficient
by making the most of what may be learned from
each trial and by avoiding unwarranted repetition. It will
help to fulfill our moral obligation to study participants,
and we believe it will benefit patients, investigators,
sponsors, and society.
Feedback may be posted at www.icmje.org by 18
*) The ICMJE plans to adopt data-sharing requirements after considering
feedback received to the proposals made here.
This editorial is being published simultaneously in Annals of Internal
Medicine, British Medical Journal, Canadian Medical Association Journal,
Journal, Deutsches Ärzteblatt (German Medical Journal),
Ethiopian Journal of Health Sciences, JAMA (Journal of the American
Medical Association), Nederlands Tijdschrift voor Geneeskunde (The
Dutch Medical Journal), New England Journal of Medicine, New Zealand
Medical Journal, PLOS Medicine, Revista Médica de Chile, The Lancet,
and Ugeskrift for Læger (Danish Medical Journal).
1. Institute of Medicine. Sharing clinical trial data: maximizing benefits, minimizing risk. Washington, DC: National Academies Press, 2015.