MPs have announced new measures today to force organisations conducting clinical medical trials to report their results. Around half the clinical medical trials that have ever been conducted have not been reported, which can lead to significant distortions in the perceived effectiveness of drugs, according to NHS data and the AllTrials campaign, which tracks the reporting of medical trials.

The Chair of the Science and Technology Select Committee, Norman Lamb MP, has written to 41 universities, including Cambridge, Oxford and Imperial, King's and University College London, informing them that their reporting of medical clinical trials will be monitored by AllTrials, and that universities which fail to improve their reporting within six months may be called to appear before the committee to explain why trials are not being reported.

The Committee released a report in October which stated that despite both UK and EU rules on the subject, "around half of clinical trials are left unreported". Pharmaceutical companies, the report found, were good at reporting their trials but universities were "mixed", and even "trusted bodies such as Public Health England and a range of NHS Foundation Trusts" had failed to publish the results of their research.

Lamb said that while some universities had already reacted to the Committee's report, the response from most had been "deeply disappointing", and that universities and other research organisations needed to address the problem "as a matter of urgency".

Campaigners for greater transparency of clinical trials say failure to publish results can dramatically alter how a drug is perceived, which could lead to unnecessary spending in the NHS. After the swine flu outbreak of 2009, the NHS spent £473m prescribing and stockpiling the antiviral drug Tamiflu, but research by the Cochrane Collection subsequently alleged that their was “evidence of selective reporting” of clinical trials of the drug. Some researchers and doctors claimed that it was in fact no more effective than paracetamol – claims which the manufacturer, Roche, vehemently denied.

AllTrials suggests that the UK should adopt the approach used by Germany’s medical regulator, the IQWiG, which does not allow drugs to be prescribed until every trial conducted using the drug has been published.

Dr Ben Goldacre, the science writer and founder of the AllTrials campaign, said he was "delighted that MPs are paying close attention to this data", and urged universities to "get in touch if they have any questions". AllTrials also monitors the reporting of clinical trials in the US and the EU. After launching its EU CTR Trials Tracker in September, the group found that 46 per cent of EU trials did not report their results, and that while 68 pre cent of commercial clinical trials had reported their results properly, just 11 per cent of academic trials had published their results as required by reporting rules.