The Washington Post
The U.S. Patent and Trademark Office will reexamine patents covering embryonic stem cell discoveries made by University of Wisconsin researchers.
The office could revoke, modify or leave intact patents that cover all embryonic stem cell research in the nation. But any such action could be months to several years away.
Critics say the patents are too restrictive and have been impeding the field.
The patent office is acting in response to challenges brought by two groups that contend the patents should never have been issued because other researchers paved the way for the breakthroughs in Wisconsin.
Patent examiners said in recent rulings that the claims by the Foundation for Taxpayer and Consumer Rights and the Public Patent Foundation raise substantial questions about whether the patents are valid.
The patents cover research by University of Wisconsin at Madison scientist James Thomson and his colleagues, who were the first to grow and isolate human embryonic stem cells in 1998. They govern five stem cell lines grown at the school as well as the methods used to grow them.