Thursday, December 10, 2009

Research throws up doubts over Tamiflu

Relenza may be a better alternative but that is not addressed below

There is no clear evidence that Tamiflu prevents complications in people with flu, an analysis suggests. While studies have shown the antiviral can cut the length of time people have symptoms by about a day, no real evidence has emerged that it prevents conditions like pneumonia, researchers said. The study, published online in the British Medical Journal (BMJ), questions the validity of research from Roche, the pharmaceutical giant that makes Tamiflu.

In August, experts said the drug was unlikely to prevent complications in children.

More than a million courses of antivirals including Tamiflu have been given out to people across Britain since the start of the swine flu pandemic. Around a million courses have been handed out through the National Pandemic Flu Service for England, with many more given out through GP surgeries.

The latest investigation, by the BMJ and Channel 4 News, found no real evidence Tamiflu stops complications and puts the cost of the drug to the Government at some £500 million. A review of 20 existing studies was carried out by a team led by experts from the Cochrane Collaboration, which last reviewed the evidence in 2005. Their updated study found Tamiflu “did not reduce influenza-related lower respiratory tract complications”. The drug was found to induce nausea while evidence of adverse reactions to the drug were “possibly under-reported”, they said.

The experts said the drug was effective in treating people preventatively after they had come into contact with somebody who was infected, and shortened the length of symptoms in those with swine flu. But they criticised some of the evidence available and said Roche had not been able to “unconditionally” provide the information needed. As a result, the team dropped eight trials that were included in their earlier review because they were unable to independently verify the findings.

Writing in the BMJ, they concluded: “Paucity of good data has undermined previous findings for oseltamivir’s (Tamiflu’s) prevention of complications from influenza.”

Dr Fiona Godlee, editor in chief of the BMJ, said: “Governments around the world have spent billions of pounds on a drug that the scientific community now finds itself unable to judge.”

In a separate review, Professor Nick Freemantle and Dr Melanie Calvert, from the University of Birmingham, looked at observational studies based on a list provided to the Cochrane authors by Roche. They conclude that “oseltamivir may reduce the risk of pneumonia in otherwise healthy people who contract flu. However, the absolute benefit is small, and side effects and safety should also be considered.”

They added: “Interpretation of the studies was difficult. “It seems likely that some patients were included in more than one study, which undermines the ability of these studies to provide independent estimates.”

Dr Godlee and Professor Mike Clarke, director of the UK Cochrane Centre, said the review called into question “not only the effectiveness of oseltamivir but the whole system by which drugs are evaluated, regulated and promoted.” In an editorial in the BMJ, they said “once a trial is completed, there needs to be ready access to the raw data behind any analyses used to license and market a drug. “When vast quantities of public money, and large amounts of public trust, are placed in drugs, the full data must be accessible for scrutiny by the scientific community. “Pending full disclosure and independent review of the raw data from Roche, the risks and benefits of oseltamivir remain uncertain.”

A spokeswoman for Roche said study summaries of Tamiflu would be made available on a password-protected site for members of the scientific community. A statement from Roche said: “Roche is aware of this issue and has been liaising with Channel 4 News and the BMJ to fully address all of the issues that have been raised. “Roche stands behind the robustness and integrity of the data supporting the efficacy and safety of Tamiflu. “Tamiflu is playing a pivotal role in the management of the pandemic (H1N1) 2009 influenza virus.”

A spokesman for the Department of Health said: “The Cochrane Review is an analysis of the use of Tamiflu to treat H1N1 [swine] influenza in healthy adults based on work on seasonal influenza. “It doesn’t cover people with underlying health conditions, or children, and we know that it may not be appropriate to generalise from effects in seasonal flu to those in a pandemic. “This is why we regularly ask for expert advice to ensure that our antiviral policy is based on the best available evidence and informed by expert judgment.

“On November 30 the Scientific Advisory Group for Emergencies (Sage) reviewed the most up to date available evidence on antiviral use and concluded that it clearly continues to point towards a benefit in those with severe illness. “Unlike seasonal flu, swine flu has caused higher levels of severe illness in the young and healthy, and in some cases death. “So it is difficult to determine who will be hardest hit.

“Our priority has always been to minimise the risk of serious illness and death from swine flu. Therefore, while there are still significant levels of H1N1 circulating, our strategy remains to offer antivirals to all patients with the illness.”


Testosterone’s aggressive impact is circumstantial. It can make you friendlier

It is popularly known as the selfish hormone, which courses through male veins to promote egotistical and antisocial behaviour. Yet research has suggested that testosterone’s bad reputation is largely undeserved. Far from always increasing aggression and greed, the male hormone can actually encourage decency and fair play, scientists have discovered.

The common belief that it makes people quarrelsome, however, can cause it to have that effect. When people think they have been given supplements of the hormone they tend to act more aggressively, even though it does nothing biological to promote such behaviour.

The findings, from an Anglo-Swiss team, suggest that rather than encouraging selfishness and risk-taking as a matter of course, testosterone has subtler effects on human behaviour that depend very much on social circumstances. The research also highlights the importance of social expectations and prejudices on the placebo effect: these can cause testosterone to influence people’s actions according to its reputation, rather than its biological effect. “It appears that it is not testosterone itself that induces aggressiveness, but rather the myth surrounding the hormone,” said Michael Naef, of Royal Holloway, University of London, an author of the study. “In a society where qualities and manners of behaviour are increasingly traced to biological causes and thereby partly legitimated, this should make us sit up and take notice.”

The popular belief that testosterone promotes aggression is founded in animal research: castrated male rodents, for example, become less combative. In humans, studies of male prisoners have found that those with higher testosterone levels are more likely to have committed a violent crime, to rebel against prison rules and get into fights.

Some scientists, however, have questioned whether the male hormone contributes directly to antisocial behaviour. The alternative view is that testosterone makes people more anxious to seek high status. This can, in different circumstances, promote either hostile or co-operative behaviour.

The study, which is published in the journal Nature, sought to test this using a common psychological exercise known as the ultimatum game. In this game, a player is given a sum of money, say £10, to share with a second player, offering as much or as little as he or she wants. If the offer is accepted, the pot is distributed that way, but if it is refused, neither player gets any cash. Players who are very aggressive, offering just £2 or £3, stand to benefit financially, but also risk coming away with nothing.

Before playing the game, a group of 60 women was given either a testosterone supplement or a placebo. “We wanted to verify how the hormone affects social behaviour,” said Christoph Eisenegger, of the University of Zurich. “If one were to believe the common opinion, we would expect subjects who received testosterone to adopt aggressive, egocentric, and risky strategies – regardless of the possibly negative consequences on the negotiation process.”

The subjects who were given testosterone supplements in fact made much fairer offers in the ultimatum game than those given a placebo, suggesting that the hormone does not promote aggression in these circumstances, but co-operation. “The preconception that testosterone only causes aggressive or egoistic behaviour in humans is thus clearly refuted,” Dr Eisenegger said.

The only exception was when participants guessed that they had been given testosterone and not the placebo. In these cases, they made more aggressive offers. “Subjects who believed that they received testosterone — regardless of whether they received it or not — behaved much more unfairly than those who believed that they were treated with a placebo,” the researchers wrote. The results support the idea that testosterone promotes status-seeking, and that this can encourage or discourage aggression depending on the circumstances. In the ultimatum game, an unfair offer risks damaging a person’s status and reputation if it is rejected, so co-operative strategies are favoured. But in situations of conflict, as in prisons, a more aggressive and risky strategy may pay off.

“In the socially complex human environment, pro-social behaviour secures status, and not aggression,” Dr Naef said. “The interplay between testosterone and the socially differentiated environment of humans, and not testosterone itself, probably causes fair or aggressive behaviour.”


1 comment:

Anonymous said...

"the male hormone can actually encourage decency and fair play, scientists have discovered."

What they actually found was that male behaviour is responsive to social circumstances. Big surprise, men are human beings. Neither male nor female humans are simply a collection of hormones and programmed responses. Do we really need a very small, badly designed experiment to tell us that all humans are complex creatures. Duh.