Gilead Sciences, Inc. announced that the US Patent & Trademark Office (PTO) has completed the second of four re-examination proceedings and has confirmed the patentability of US Patent No. 5,922,695, which covers the composition of matter for Viread (tenofovir disoproxil fumarate). On May 20, Gilead announced that the US PTO confirmed the patentability of US Patent No. 6,043,230.

The four US PTO review proceedings were initiated July 2007 in response to a challenge issued by the Public Patent Foundation (PUBPAT) in March 2007 for US Patents No. 5,922,695; 5,977,089; 5,935,946; and 6,043,230. In its request for the re-examinations, PUBPAT claimed that prior art existed that would have impacted the issuance of the original patents.

"Of the four patents originally under PTO review, this composition of matter patent is the most integral to Viread's novel exclusivity," said Gregg Alton, Senior Vice President and General Counsel. "We are pleased with the PTO's swift analyses and actions, which have confirmed the strength of our patent position."

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company's mission is to advance the care of patients suffering from life-threatening diseases worldwide.