Pfizer’s Celebrex Could Face Generic At-Risk Launches In May
This article was originally published in The Pink Sheet Daily
Executive Summary
Pfizer had hoped to gain an extra 18 months of patent protection with a reissue patent granted last year but a district court ruled the method of use patent is invalid.
Pfizer Inc. could face generic competition for its blockbuster Celebrex (celecoxib) as early as May 30 now that a court has ruled that a reissue patent on the pain drug is invalid.
In a March 12 order, U.S. District Judge Arenda Wright Allen, of the Eastern District of Virginia, dismissed Pfizer’s patent infringement suit against five generic manufacturers finding that the method of use patent covering Celebrex is invalid for obviousness-type double patenting. The reissue patent (RE44048), a revised version of an earlier patent (No. 5,760,068), expires on Dec. 2, 2015.
Pfizer immediately announced it plans to appeal the ruling. As a result, any generic launch would be at risk until the U.S. Court of Appeals for the Federal Circuit issues a final decision.
In 2008 the Federal Circuit ruled that the ‘068 was invalid for obviousness-type double patenting, thus clearing the way for generic competition on May 30, 2014 when patents covering the active compound and composition of Celebrex expire following a six-month pediatric exclusivity period. Pfizer gained an extra 18 months of protection when it was awarded the reissue patent last year.
The day the patent issued Pfizer filed an infringement suit against Lupin Pharmaceuticals Inc., Teva Pharmaceuticals USA Inc., Mylan Pharmaceuticals Inc., Watson Laboratories Inc. (now Actavis) and Apotex Inc. (Also see "Celebrex Reissue Patent Reawakens Generic Litigation" - Pink Sheet, 11 Mar, 2013.). The defendants argued that the patent was non-infringed and invalid.
On Feb. 26, the court heard oral arguments on the parties’ motions for summary judgment in the case, G.D. Searle LLC v. Lupin. A trial was scheduled to begin on March 19 on the infringement claims.
The judge concluded that the ‘048 patent is invalid because Pfizer filed the reissue application as a continuation-in-part application rather than as a divisional application and thus an earlier divisional patent may be used to invalidate it.
Sanford C. Bernstein & Co. analyst Tim Anderson said in a note that it is not certain whether generics will launch in May. It is highly likely that Pfizer will try to stop them with a preliminary injunction, “or generics could be fearful of infringing the patent if an appeals court finds it valid,” Anderson said. “However, it seems likely that odds are in favor of generics launching early.”
Celebrex is Pfizer’s fourth top revenue generator with worldwide sales of $2.9 billion in 2013. Without the reissue patent in play, generic manufacturers will not be able to get 180-day marketing exclusivity as the first ANDA filer since the exclusivity period was triggered when the court ruled the ‘068 patent was invalid (Also see "Celebrex Generics: Will Any Qualify For 180-Day Market Exclusivity?" - Pink Sheet, 7 Mar, 2014.).