Roche denies increase in Tamiflu resistance

Switzerland-based drug major Roche says that, since March 2005, there have been no new cases of patients infected with H5N1 influenza virus strains that are resistant to its world-leading antiviral Tamiflu (oseltamivir). The company added that the scientific data available does not substantiate the emergence of increased resistance to the drug, which has been adopted by governments worldwide as the first line of defence against the predicted outbreak.

Roche's influenza pandemic taskforce leader, David Reddy, explained that it has issued the statement in response to "erroneous speculation that resistance to Tamiflu is increasing." He added that "governments can be confident that Tamiflu remains a critical drug, as recommended by the WHO [World Health Organization], for stockpiling to prepare for an influenza pandemic and for physicians and patients to treat and prevent flu when it hits."

The announcement follows a UK Royal Society and Academy of Sciences report which was critical of the UK government's reliance on Tamiflu alone as a means of combating pandemic influenza (Marketletter November 27). Roche said that, to date, there have only been three documented cases of H5N1 becoming resistant to the drug, adding that in one case the prophylactic dose (75mg daily) rather than the treatment dose (75mg twice daily) was administered to a patient already displaying clinical symptoms. The firm went on to say that, when the correct dose was used, the patient in question made a full recovery, and that, when examined, the resistant virus was shown to cause less severe infection and was harder to transmit.