Roche denies increase in Tamiflu resistance

Earlier in the year, a GlaxoSmithKline sponsored a study discovered that its Relenza antiviral treatment is less likely to lead to drug-resistant flu strains than Tamiflu.

Roche said the incidence of resistance rates for Tamiflu remain low in treated patients at 0.32% in adults and 4.1% for children. Roche said it regularly tests the treatment and resistance is rare. According to the company, there have been no new cases of resistance seen in patients infected with H5N1 virus since March 2005.

“Over the last few months, there has been erroneous speculation that resistance to Tamiflu is increasing. This is an area that Roche and independent groups have been closely monitoring and there is no scientific evidence to suggest this is happening,” said David Reddy, Roche's influenza pandemic taskforce leader.

All H5N1 viruses that have been tested are susceptible to neuraminidase inhibitors like Tamiflu.

As with any antiviral medication, there is a theoretical risk that a virus may emerge with decreased sensitivity to a drug. To date, there have only been three documented cases of Tamiflu resistance to avian influenza H5N1.