Finding and appraising qualitative evidence
Tamiflu: securing access to medical research data< Back to search results
- Format Texts
- Language/s English
- Target Audience Further education, Self-directed learning
- Difficulty Introductory
Key Concepts addressed
- 1-3a Beware of conflicting interests
- 2-2b All fair comparisons and outcomes should be reported
- 1-2g Common practice is not always evidence-based
- 1-2h Newer is not necessarily better
Update, June 2016
The Oxford Centre for Evidence-Based Medicine has created an interactive timeline of the events of since publication of their review showing that data on the adverse effects of tamiflu had been under-reported.
This includes the responses of regulators, journals, academics, clinicians and the manufacturers.
Our original item on this story is below.
In November 2012 we wrote about Roche’s refusal to release clinical research data relevant to independent assessment of the effects of Tamiflu, and to the campaign to gain access to all of the data.
That campaign has now succeeded, and the full clinical data set has been analysed by Cochrane reviewers. The conclusions are of great importance.
The Cochrane reviewers found that the published reports of the drug included only a highly selective subset of all the clinical data. Indeed, the published studies released by Roche were so incomplete and unreliable that the reviewers discarded them and went back to the original data recorded in the very detailed Clinical Study Reports submitted to the drug licensing authorities.
When the full set of data was analysed, the reviewers found evidence of substantial and serious side-effects that were not reported in the original publications.
Here’s what they found when they looked at the whole picture
The reviewers assessed full internal reports of 20 trials of Tamiflu (oseltamivir) and 26 trials of another drug in the same class, Relenza (zanamivir). In total, these trials involved over 24,000 patients.
When they looked at all of the data, they found that Tamiflu resulted in a modest reduction in flu recovery time in adults, whilst any benefits in children were unclear. There was no evidence of a reduction in either hospitalisations or serious complications, and there was insufficient evidence to support the use of Tamiflu in attempts to prevent the spread of influenza.
Importantly, Tamiflu was shown to have important adverse effects:
- An increased risk of nausea and vomiting in both adults and children
- An increased risk of psychiatric events when used to prevent influenza
- A reduction in the production of antibodies to fight infection.
What are the implications?
Current guidance on the use of both Tamiflu and Relenza in the prevention or treatment of influenza should be revised to take account of the evidence of the smaller than claimed benefits and the increased risk of harms.
What went wrong?
It seems that Roche spun the research findings to fit their commercial needs and withheld evidence of the adverse effects of its product. This paid off because it resulted in massive revenues, as governments stockpiled Tamiflu against a possible H5N1 influenza pandemic.
This raises questions:
- How was Roche able to put out misleading research based on incomplete data?
- Why did the regulators and governments worldwide invest billions of pounds based on this flawed evidence, which, in principle, was available to them at the time)?
This is an unfortunate (and expensive) reprise of some of the key themes covered in Testing Treatments:
In the words of the Cochrane reviewers:
“Drug approval and use cannot be based on biased or missing information any longer. We risk too much in our population’s health and economy.”
- Jefferson T, Jones MA, Doshi P, Del Mar CB, Hama R, Thompson MJ, Spencer EA, Onakpoya I, Mahtani KR, Nunan D, Howick J, Heneghan CJ. Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database of Systematic Reviews 2014, Issue 4. Art. No.: CD008965. DOI: 10.1002/14651858.CD008965.pub4.
- The Tamiflu Trials. BMJ 2014; 348 doi: http://dx.doi.org/10.1136/bmj.g2630 (Published 10 April 2014)Links to the Editorial on the BMJ website
- The Department of Health spent £424 million on stockpiling Tamiflu. www.publications.parliament.uk/pa/cm201314/cmselect/cmpubacc/295/295.pdf
Our original article, published in November 2012 follows:
In the light of Roche’s ongoing refusal to release clinical research data on the effectiveness and safety of Tamiflu for independent scrutiny, Health Action International (HAI) Europe recently held a seminar about improving access to this kind of data. Their YouTube channel contains a series of talks from the seminar that address this issue.
Access to medical research data is an essential foundation of rational health care policy, and the consequences of restricting such access are the subject of growing debate.
The HAI Europe Open Seminar explored this topic using the 2009 outbreak of H1N1 influenza (also known as the Mexican or Swine flu) as a case study, with interesting presentations by Dr. Tom Jefferson (Cochrane Acute Respiratory Infections Group) and Dr. Deborah Cohen (British Medical Journal), followed by a lively Q&A session.
Find out more
HAl Europe is an independent network working to improve access to, and the rational use of, essential medicines with evidence-based advocacy. You can find out more about their work on their website.