Singapore: A patent for hepatitis B and HIV/AIDS drug Viread has been invalidated by China's State Intellectual Property Office (SIPO). The drug is being manufactured by Gilead Sciences.

The State Intellectual Property Office agreed with Aurisco, a China active pharmaceutical ingredient (API) maker, that Viread was not a novel drug because its active ingredient was already discovered in the Czech Republic in 1985.

Gilead had already lost patent protection for the drug in India and Brazil. Earlier this year, Gilead also made an undisclosed settlement with Teva Pharma to end its challenge to Viread's US patent.