A group of senior Asian medical experts will today call for the stockpiling of a second antiviral drug in efforts to tackle the threat of a bird flu pandemic, and an end to patents on both drugs.

Writing in the Lancet, the British medical publication, Kenneth Tsang, from the University of Hong Kong, and colleagues from Korea, Malaysia and Singapore argue that zanamivir, marketed as Relenza by GlaxoSmithKline, could prove a powerful alternative to oseltamivir, sold by Roche as Tamiflu, which has hitherto dominated discussions over drug treatment for bird flu.