(Reuters) - A federal appeals court on Thursday refused to revive Teva Pharmaceutical Industries Ltd's patent infringement suit against AstraZeneca Pharmaceuticals LP for the rights to Crestor, a multibillion-dollar cholesterol fighter.
In a ruling that upheld a lower court, the U.S. Court of Appeals for the Federal Circuit invalidated Teva's patent for Crestor on grounds that AstraZenec invented it first.
Teva in 1999 patented a method for stabilizing drugs known as statins, which help lower cholesterol. Statins are inherently unstable and require an added compound to be medically effective.
In 2008, Teva sued AstraZeneca over its cholesterol drug Crestor, which contains the active ingredient rosuvastatin calcium, a stabilized statin. AstraZeneca argued that it first manufactured a batch of the drug in mid-1999, before Teva obtained its patent. The batch included a compound Teva later identified as a stabilizer.
The U.S. District Court for the Eastern District of Pennsylvania sided with AstraZeneca, invalidating the Teva patent based on AstraZeneca's prior invention. Under federal law, a patent is invalid if someone else made the invention first and did not abandon, suppress or conceal it.
On appeal, Teva argued that AstraZeneca in 1999 did not appreciate the stabilizing effect of the compound it added to the drug formulation. But the Federal Circuit found such an appreciation was not necessary.
AstraZeneca understood that it had created a stable formulation, and it understood the components of that formulation, the court found.
"AstraZeneca did not need to appreciate which component was responsible for stabilization," Judge Richard Linn wrote on behalf of the three-judge panel.
Denise Bradley, a spokeswoman for Teva, declined to comment on the litigation.
AstraZeneca spokeswoman Elizabeth Renz said the company was pleased with the court's ruling invalidating Teva's formulation patent.
In a separate case, AstraZeneca is fighting several companies seeking to sell cheap versions of Crestor, including Mylan, Teva, Sun, Aurobindo, Par, Watson, Sandoz and Apotex. A Delaware federal judge in June 2010 upheld the validity of AstraZeneca's Crestor patent, which keeps generics out of the market until 2016. That case is also currently on appeal before the Federal Circuit.
The latest ruling was in the case Teva Pharmaceutical Industries Ltd v. AstraZeneca Pharmaceuticals LP et al, U.S. Court of Appeals for the Federal Circuit, No. 2011-1091.
(Reporting by Terry Baynes; Editing by Eileen Daspin and Jerry Norton)