The antiviral medication Tamiflu shortened the length of time patients experienced flu symptoms, and reduced rates of complications and hospitalizations from the virus, a new study finds. But it did not have an effect on those with flu-like symptoms who did not have the flu.
The findings already are being challenged by some because they conflict with those of another report almost a year ago that raised serious questions about the drug's safety and efficacy. That report claimed the harms are understated and called government stockpiles of the antivirals a waste of money. Critics are latching on to the involvement of drugmaker Roche in the new study as evidence its findings are questionable even though authors say Roche had no active role in the new report.
“That's the conclusion I would have expected from a Roche-sponsored reanalysis,” said Dr. Peter Doshi, assistant professor of pharmaceutical health services research at the University of Maryland. Doshi was part of a team to review a Cochrane study published last year in The BMJ, which questioned government stockpiling of antiviral flu medications.
The new report comes as the U.S. is in the throes of what health officials warn could be a severe flu season. The proportion of people reporting flu-like illness has remained above the national baseline for the ninth consecutive week, according to estimates from the Centers for Disease Control. Earlier this month, CDC director Dr. Tom Frieden recommended early, aggressive treatment with antivirals in patients suspected of having the flu virus, even if the virus is not confirmed.
“It's is not a perfect antiviral, but it should be a component of treatment,” said Dr. Arnold Monto, an epidemiology professor at the University of Michigan, one of the authors of a new study designed to clear up the debate about the efficacy of oseltamivir (Tamiflu) treatment. “There are few side effects so the risk-benefit is better” than using antibiotics. "Our findings confirm Tamiflu's role,” he said.
Monto and a team of researchers obtained published and unpublished Roche-sponsored randomized, placebo-controlled, double-blind trials on the drug for the meta-analysis, which included nine trials conducted between 1997 and 2001 and a total of 4,328 patients. Patients had been given either 75 mg doses of oseltamivir or a placebo, within 36 hours of feeling sick, and continued the drug regimen for five days at 12-hour intervals.
The analysis found that among patients infected with the flu virus, symptoms like aches, sore throat, nasal congestion and chills, cleared up in about four days, while it took an extra day for placebo patients. They also had fewer lower respiratory complications—like pneumonia or bronchitis—requiring antibiotics more than 48 hours later, and were less likely to be hospitalized. Although side effects like nausea, vomiting and gastrointestinal disorders were more prevalent, there was no evidence of serious adverse events, like neurological or psychiatric disorders.
The findings from Monto, Joanna Dobson and Stuart Pocock of the London School of Hygiene & Tropical Medicine and Dr. Richard Whitley of the University of Alabama at Birmingham, were published Thursday in the journal The Lancet.
The Cochrane review used some of the same data obtained by the Lancet researchers, but found no evidence that the drug reduced pneumonia complications, led to fewer hospitalizations or stopped the spread of a pandemic. It also said worrisome side effects—like the potential for psychiatric and renal problems and hypoglycemia—were understated. “I think (the Lancet authors) have erred in their interpretation of the evidence,” Doshi said.
The new study notes that the meta-analysis was funded by the Multiparty Group for Advice on Science (MUGAS), which obtained an unrestricted grant from Roche, stipulating the manufacturer could not be involved in the review process except to provide requested data and clarifications when needed. Results were not shared with the manufacturer until the analysis was completed, the paper said. It is also noted that one researcher, Dr. Richard Whitley, is a board member of Gilead Sciences, which has patents on the oseltamivir medication marketed by Roche. The manufacturer did not respond to requests for comment.
However, Monto said the Cochrane group “uses that as a smokescreen.” If The Lancet believed total independence had not been demonstrated, it would not have published the results, he said.
The CDC continues to stockpile the drug and recommends physicians use it quickly in symptomatic patients. It disagreed with the findings last year in the BMJ, and said that report did not tell the complete story.
Widespread flu activity is being reported in 44 states with 9,926 flu-related hospitalizations since the start of flu season. Use of Tamiflu, Relenza and Rapivab are most effective within the first 48 hours of symptoms, said Dr. Tom Frieden, the agency's director, during a media briefing this month.
“If those treated with Tamiflu don't have influenza, the benefit is going to be much higher,” he said. “More than half of the people with flu-like illness have confirmation that they have flu on detailed studies, but don't wait for confirmatory testing... it's not necessary to get the tests done before you treat the patient.”
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