Professor Chris Del Mar from Bond University’s Centre for Research in Evidence-Based Practice (CREBP) has been in the media spotlight recently when The Cochrane Collaboration’s review into the effectiveness of Tamiflu and Relenza made headline news around the world.
As Coordinating Editor for The Cochrane Collaboration’s Acute Respiratory Group, Dr Del Mar was also part of the international review team with researchers from Australia, Italy, Japan, the UK and the US which accessed and reviewed more than 160,000 pages of pharmaceutical company trial clinical study reports (CSRs) over the past six years to develop “the most robust, comprehensive review on neuraminidase inhibitors that exists”.
Published on April 10 by The Cochrane Collaboration and the British Medical Journal, the review found that there is “no good evidence to support claims that (the neuraminidase inhibitors found in) Tamiflu and Relenza reduce admissions to hospital or the complications of influenza”, sending shockwaves through the health sector and generating national media coverage in Australia, Canada, the US and various countries in Africa, Asia and Europe.
Most significantly, the findings attracted strong attention from governments worldwide that have spent billions of dollars stockpiling these drugs.
These stockpiles have been growing since 2002 in anticipation of an influenza pandemic and increased dramatically following the outbreak of Swine Flu (H1Ni virus) in April 2009. In the US, the government has reportedly spent $USD1.3 billion buying up a strategic reserve; the British have spent almost £424 million; and here in Australia, the current value of the stockpile which includes Tamiflu, Relenza and other products is $AUD192 million.
Previously, a lack of access to available trial data hampered the efforts of the Cochrane researchers to verify the safety and effectiveness of Tamiflu, leading to questions over the decisions to stockpile drugs in cases where the risks and benefits from randomised trials with volunteer patients remained hidden from public scrutiny.
The manufacturers of Tamiflu and Relenza – Roche and GlaxoSmithKline – have now made the complete reports of the original research available to the Cochrane team resulting in this latest updated review based on the full internal reports of 20 Tamiflu and 26 Relenza trials collectively involving more than 24,000 people.
The findings not only challenge the assumption that neuraminidase inhibitors are effective in combatting influenza, but suggest that there are insufficient grounds to support the use of Tamiflu in the person-to-person spread of influenza.
“We were able to show that, as previously found, these neuraminidase inhibitors do reduce symptoms but that, compared to a placebo, they only shorten the illness by about half a day,” said Professor Del Mar.
“There’s a chance that people feel better from taking the drug so then get around spreading the virus – which is exactly the kind of behaviour you don’t want in a pandemic.”
The review team also confirmed the increased risk of suffering nausea and vomiting as a side effect of the drugs, and an increased risk of headaches, psychiatric disturbances and renal events when Tamiflu was used in prevention trials.
Adults treated with Tamiflu also had significantly lower increases in the number of antibodies which the body needs to fight infection.
The review has prompted widespread questions about the stockpiling of drugs and the methods used to determine the effectiveness of various drug treatments, with the responses now coming in from the manufacturers, various Government bodies and health authorities.