Roche's Tamiflu engine is skipping a few beats. Some seasonal flu strains circulating in Europe are "significantly" resistant to the anti-influenza med, stockpiled around the world as insurance against a flu pandemic. According to the European Centres for Disease Control, 13 percent of H1N1 samples contained a mutation associated with high levels of Tamiflu resistance.
This is the first clear sign of resistance to the antiviral. Previous studies have shown only about 0.4 percent of seasonal viruses carrying resistance, while only four patients with H5N1--so-called avian flu--were infected with resistant strains.
It's not good news for Roche, which turned Tamiflu into a blockbuster by selling it to governments in quantity as they prep for a possible pandemic. But it could benefit GlaxoSmithKline, which makes another anti-flu med, Relenza. The European medicines agency has stressed the importance of stockpiling a variety of antivirals, not just Tamiflu. The EMEA says resistance to Relenza is extremely rare.