The United States Patent & Trademark Office (USPTO) has granted Pfizer a reissue patent (US Patent No. RE44048), covering methods of treating osteoarthritis and other approved conditions with celecoxib, the active ingredient in Celebrex. The reissue patent will expire on December 2, 2015, which includes six months of paediatric exclusivity. The basic patent for celecoxib expires on May 30, 2014, which also includes six months of paediatric exclusivity.

“Continued development of new medicines that enhance patient lives is supported by protecting intellectual property and innovation,” said Amy Schulman, executive vice president and general counsel for Pfizer. "We are pleased with the reissuance of this patent protecting the invention of using celecoxib to treat osteoarthritis and other approved conditions, and have initiated legal proceedings to enforce our intellectual property rights through December 2, 2015.”

Pfizer filed suit  against Teva Pharmaceuticals USA, Inc., Mylan Pharmaceuticals Inc., Watson Laboratories, Inc., Lupin Pharmaceuticals, USA, Inc., Apotex Corp., and Apotex, Inc. in the United States District Court for the Eastern District of Virginia for infringement of the reissue patent. Each of these generic companies previously filed an abbreviated new drug application with the United States Food and Drug Administration seeking approval to market a generic form of celecoxib in the United States beginning in May 2014, prior to the December 2, 2015 expiration of the reissue patent.