GSK becomes first major pharmaceutical company to commit to publishing the results of all its drug trials

GlaxoSmithKline, Britain's biggest pharmaceutical company, has become the world's first drug major to commit to publishing clinical trial data in a move that campaigners hope will increase the likelihood of medical breakthroughs and protect patients from ill-advised prescriptions.

GSK's decision to publish the results of all drug trials comes just a year after it paid $3bn (£1.9bn) to settle claims it tricked and bribed doctors into prescribing children dangerous antidepressants. The allegations included a failure to reveal two scientific studies that challenged the efficacy of prescribing Paxil, known as Seroxat in the UK, to children.

The company's commitment to data transparency follows a high-profile campaign led by Ben Goldacre, a doctor and Guardian columnist, who helped expose drug companies' manipulation of clinical trial data.

GSK said it will "publish CSRs [clinical study reports] for all of its medicines once they have been approved or discontinued from development and the results have been published". It will eventually lead to the publication of all trial data dating back to the formation of the company in 2000 when Glaxo Wellcome merged with SmithKline Beecham.

Patrick Vallance, GSK's president of pharmaceutical research and development, said: "We are committed to being transparent with our clinical trial data to help advance scientific understanding and inform medical judgment. All those involved in the conduct and publication of clinical research, whether healthcare companies like GSK, academia or research organisations, have a role to play in ensuring that the data they generate are made publicly available to help bring patient benefit."

The company said it would publish CSRs for clinical outcomes trials for all approved medicines dating back to the formation of the company in 2000. In a speech last year that paved the way for the move, GSK's chief executive, Sir Andrew Witty, said opening clinical trial data to a wider audience would help find cures for diseases such as malaria and tuberculosis as well helping develop novel antibiotics.

Goldacre said GSK's decision to publish CSRs rather than just summary results and academic journal articles was a "genuinely historic" milestone for the future development of medicine.

He said that pharmaceutical companies' refusal to publish all the data has "harmed patients" because it means doctors only have access to some of the information.

"Trials with positive results are twice as likely to get reported as negative results," Goldacre said. "You can't make informed decisions about which treatment is best for the patient on the basis of just half the results, especially as it's the unflattering ones that are withheld."

Goldacre, who sparked a public debate about the morals of the drug industry with his book Bad Pharma, said he met Witty to discuss his All Trials clinical data campaign on Friday.

He said he expected GSK's decision would put "huge pressure" on the world's other big pharmaceutical companies to commit to publishing their own trial data.

"Withholding this data is utterly indefensible," he said. "It is the 21st century equivalent of bloodletting. It's insane."