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| |  Cochran Review Questions Benefit of Oseltamivir in Healthy Adults By Denise Baez NEW YORK -- December 10, 2009 -- According to a controversial study published today online in BMJ, researchers from the Cochran Review have concluded that neuraminidase inhibitors have only modest effectiveness, at best, against symptoms of influenza in otherwise healthy adults. In light of the results, the authors recommend that the use of oseltamivir or zanamivir be regarded as optional for reducing the symptoms of seasonal influenza. “Our Cochrane review team has tried to obtain the data needed to verify claims that oseltamivir lowers serious complications of influenza such as pneumonia,” wrote coauthor Peter Doshi, PhD, Massachusetts Institute of Technology, Cambridge, Massachusetts, in an accompanying commentary. “We failed, but in failing discovered that the public evidence base for this global public health drug is fragmented, inconsistent, and contradictory.” They also call for independent randomised trials to determine the efficacy of oseltamivir for the prevention of complications from influenza, as current findings are uncertain. Tom Jefferson, MD, Acute Respiratory Infections Group, Cochrane Collaboration, Rome, Italy, and colleagues assessed the effects of neuraminidase inhibitors in preventing or reducing the symptoms of influenza. They also assessed its effectiveness on transmission and complications from influenza in healthy adults. The authors analysed 20 randomised, placebo-controlled studies of neuraminidase inhibitors in otherwise healthy adults exposed to naturally occurring influenza. Of the studies, 4 were on prophylaxis, 12 were on treatment, and 4 were on postexposure prophylaxis. Results showed that neuraminidase inhibitors as prophylaxis had no effect against influenza-like illness or asymptomatic influenza. The efficacy of oral oseltamivir against symptomatic laboratory-confirmed influenza was 61% at 75 mg daily and 73% at 150 mg daily. Inhaled zanamivir 10 mg daily was 62% efficacious. Oseltamivir had an efficacy of 58% for postexposure prophylaxis and 84% in 2 trials looking at household transmission prevention. Zanamivir performed similarly. Oseltamivir did not reduce influenza-related lower respiratory tract complications. In light of this review, guidelines and policies from the Centers for Disase Control (CDC) and the US Department of Health & Human Services (HHS) are being questioned. “The implications to policy (CDC influenza and HHS pandemic preparedness policy), the first order of business is to clarify whether the CDC, HHS, and WHO have independently analysed the data,” Dr. Doshi told Doctor’s Guide. “Both the CDC and HHS cite the same single key paper (Kaiser et al 2003) in the literature which concludes that Tamiflu reduces complications. Did they believe in that paper’s results on trust or did they independently verify those claims? Eight of the 10 trials the claims are based on were never published.” “The US Food and Drug Administration has an explicit statement on the [oseltamivir] product label saying that the drug has not been shown to reduce complications,” he continued. “Despite this, the CDC and the HHS say this drug reduces complications.” He added that the way in which public health decision are made may itself need to be re-examined. In response, Roche said that they firmly believe in the robustness of the data, and say that full access to data has been granted to Governments and regulatory authorities. SOURCE: BMJ
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