The respected British Medical Journal (BMJ) will refuse to publish research papers on drugs unless the clinical trial data behind these studies is made available for independent scrutiny.
The requirement to make anonymised patient-level data available "on reasonable request" will apply to all clinical trials of drugs and medical devices from January 2013, the BMJ said in an editorial.
The move increases the pressure on drug companies to lift the lid on data secrets amid growing criticism that lack of disclosure hampers the ability of doctors and medical researchers to assess the true value of products.
Patient-level data, which sits behind the published results of clinical trials, is a potential treasure trove for scientists wanting to test drug company claims and expose product deficiencies.
Companies have been reluctant to release this information, but GlaxoSmithKline set a precedent this month by announcing that it would make such data available from its trials.