Resistance to a popular anti-influenza drug from Switzerland’s Roche may be more common than previously thought, raising questions about how it should be used in a major pandemic, Japanese researchers said on Thursday.
Tamiflu, or oseltamivir, belongs to a class of drugs known as a neuraminidase inhibitors which work by blocking the action of viral enzymes.
But Yoshihiro Kawaoka and colleagues at the University of Tokyo, who analysed samples from a group of 50 Japanese children given the drug, found that flu viruses had mutated to outwit the medicine in 18 percent of the patients.
Writing in The Lancet medical journal, they said that resistant strains of viruses were first detected 4 days after the start of treatment and on each successive day of the study.
In an accompanying commentary, Anne Moscona of the Mount Sinai School of Medicine in New York, said the research showed more research was needed and doctors needed to find out urgently whether virus resistant to the drug was transmissible.
Tamiflu was used earlier this year to help protect Asian workers culling chickens infected with bird flu.