Incidence of Tamiflu Resistance Very Low, Study Shows

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New data published by the World Health Organization (WHO) has confirmed a low frequency of resistance to the flu drug Tamiflu between 2003 and 2006, Roche announced.

The information, published by WHO’s Neuraminidase Inhibitor Susceptibility Network, shows that resistance to Tamiflu (oseltamivir) of approximately 0.3 percent was seen during the past three influenza seasons, during which the drug was used extensively in Japan. This level of resistance is extremely low compared with the 65 percent rate seen in Japan with another antiviral, amantadine.

“These results confirm that the potential for the development of resistance to Tamiflu is very low, even when used extensively in the management of seasonal influenza,” David Reddy, head of Roche’s Pandemic Task Force, said.

The possible development of antiviral resistance is of concern for pandemic influenza preparedness, Roche said. However, to date there have only been three documented cases of avian influenza H5N1 resistance to Tamiflu. Two other possible cases of resistance of H5N1 to Tamiflu in Egypt have been identified and are currently under investigation.

WHO recently reconfirmed that stockpiling antivirals is the only way to ensure that sufficient supplies are available in the event of a pandemic. Roche has been working closely with WHO to ensure governments are aware of the importance of stockpiling antivirals in the event of a pandemic situation. The company has fulfilled pandemic orders for Tamiflu from more than 80 countries worldwide.