A review of all the clinical trial evidence for flu medications Tamiflu and Relenza has found that they are not as effective as they seemed when only some of the data was assessed.

The new review is based on detailed clinical study reports from clinical trials of the drugs which the researchers from Cochrane Collaboration have spent four and a half years battling to access. It shows there is no good evidence that the drugs prevent the spread of flu or reduce dangerous complications and only helped reduce symptoms by half a day compared to not using the drugs.

The UK government has spent £473 million on Tamiflu and £136 million on Relenza since 2006, and other countries have stockpiled it too. When the government made the decision to stockpile the medications its medicines regulator MHRA had not seen all of the evidence.

Editor-in-Chief of the BMJ Dr Fiona Godlee said: “This review is the result of many years of struggles to access and use trial data, which was previously unpublished and even hidden from view. It highlights with certainty that future decisions to purchase and use drugs, particularly when on a mass scale, must be based on a complete picture of the evidence, both published and unpublished. We need the full data from clinical trials made available for all drugs in current use. With the new European Clinical Trials Directive bringing in rules for future drugs, it highlights the enormous challenge we face. We need the commitment of organisations and drug companies to make all data available, even if it means going back 20 years. Otherwise we risk another knee-jerk reaction to a potential pandemic. And can we really afford it?”

Professor Carl Heneghan, Director, Centre for Evidence-based Medicine, Oxford, co-founding organisation of the AllTrials campaign: “This is an important moment in the AllTrials campaign. As an author of the Cochrane review, it is clear that access to full clinical study reports is fundamental to establish the effectiveness of treatments. Full access has allowed us, for the first time, to quantify the harms and the lack of benefits of Tamiflu and Relenza, which have been extensively stockpiled around the world. What we need to do now, is have the courage to make all clinical study reports available for treatments that are currently available and used.”

Dr Síle Lane, Director of Campaigns, Sense About Science, co-founding organisation of the AllTrials campaign: “There is no excuse for not publishing results but a huge public benefit to having a complete picture of what was found in trials on treatments currently in use. We might find drugs that work better than we think.  We’ll soon have European law that will mean all drug clinical trials will have to be registered and results reported. Since the launch of the AllTrials campaign last year a number of companies have made commitments to make data from past clinical trials available to researchers. Hundreds of thousands of people have taken part in trials that haven’t published results. It is a betrayal of their trust that this data remains locked up and not available for scrutiny.”

Dr Ben Goldacre, author and co-founder of AllTrials: This is a pivotal moment. Tamiflu has become the poster child for clinical trials transparency, and it illustrates perfectly why researchers need access to the full methods and results of all trials, to help doctors and patients make informed decisions about treatments. But we must remember that Roche broke no laws, and Tamiflu is not an isolated case. The evidence clearly shows that important information on the methods and results of clinical trials on the treatments we use today are still being routinely and legally withheld, throughout medicine.

Roche have slowly become more transparent, and should be applauded for this. Many other companies are still lagging behind. Some, such as InterMune, are still suing regulators to make them withhold trials information. Regulators, policy makers, and public health officials must demand full access to the methods and results of all trials, on all treatments currently in use. But industry itself has much to gain by supporting transparency. The world has changed, and they must change with it.”

More coverage:

Tamiflu: Britain spent £424m on a drug that shortens bouts but is no cureGuardian

Scientists say UK wasted £560m on flu drugs that are not provenGuardian

What the Tamiflu saga tells us about drug trials and big pharmaGuardian

Tamiflu: Millions wasted on flu drug, claims major reportBBC

Flu pandemic: ‘No benefit from Tamiflu treatment’BBC

Tamiflu: drugs given for swine flu ‘were waste of £500m’The Telegraph

Tamiflu: how drug became last line of defence against fluThe Telegraph

Pandemic flu: was the Tamiflu stockpile a waste of money?Channel 4

Tamiflu’s effectiveness in cutting hospitalizations questionedCBC

£500m stockpile of Tamiflu ‘no better than paracetamol’The Times

Review raises questions about TamifluSBS Australia

Use of anti-flu medicine Tamiflu ‘should be reviewed’ITV

Government should ‘review use of anti-flu drug Tamiflu’ITV

Flu experts line up to defend tamiflu against new studyNBC News

Study questions Tamiflu’s effectiveness against pandemicsWall Street Journal

Review raises question over TamifluBelfast Telegraph

The drugs don’t work: Britain wasted £600m of taxpayers’ money on useless flu pills stockpiled by Government in case of pandemicThe Independent

The entire system of drug evaluation is flawed – Dr Fiona Godlee in The Independent

Scientists say UK ministers wasted millions on flu medicineFinancial Times

Ministers blew £650 million on useless anti-flu drugs: Cash spent on stockpiling treatments that ‘worked no better than paracetamol’Daily Mail

Researchers, regulators and Roche row over stockpiled drug TamifluReuters

Billions of dollars being wasted on ‘ineffective’ Tamiflu drug: ResearchersThe Times of India