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Are clinical trial data shared sufficiently today? No

BMJ 2013; 347 doi: (Published 09 July 2013) Cite this as: BMJ 2013;347:f1880
  1. Ben Goldacre, Wellcome research fellow in epidemiology
  1. 1London School of Hygiene and Tropical Medicine
  1. ben{at}

The AllTrials campaign asks for all trials to be registered and their results published. Ben Goldacre says we need the evidence to make informed decisions about medicines. John Castellani (doi:10.1136/bmj.f1881) says mandatory disclosure could affect patient privacy, stifle discovery, and allow competitors or unscrupulous actors to use the information

When discussing transparency it is important to be clear on what is being requested, as obfuscation is sometimes used to avoid discussing simple fixes. At stake are four levels of information about trials: (1) knowledge that a trial has been conducted, from a clinical trials register; (2) a brief summary of a trial’s results, in an academic journal article or regulatory summary; (3) longer details about the trial’s methods and results, from a clinical study report where available; (4) individual patient data. The AllTrials campaign calls only for the first three to be published.

The status quo is plainly unsatisfactory. The most current review—with no cherry picking permitted—estimates that around half of all trials for the treatments being used today have gone unpublished; and that trials with positive results are twice as likely to be disseminated.1 This is a problem for both industry and academic trials.

Although some in industry claim that these problems are in the past, in reality all supposed fixes have failed. In 2005, journal editors passed regulations stating that they would publish only registered trials: the evidence now shows these regulations have been widely ignored.2 In 2007, US legislation was passed requiring all trials since 2008 to post results on within a year of completion: the best published evidence shows this law has been ignored by 60-90% of trials.3 If industry representatives believe these problems have been fixed, they should present published evidence to support their case, with methods and results that …

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