In a case involving multiple defendants seeking to sell generic versions of the drug rosuvastatin calcium, currently marketed as Crestor®, the U.S. Court of Appeals for the Federal Circuit, a divided panel, found that the patent at issue was valid and enforceable.  In re Rosuvastatin Calcium Litigation, Case Nos. 10-1460 through -1473 (Fed. Cir., Dec. 14, 2012) (Newman,  J.) (Plager, J., concurring) (Mayer, J., dissenting). 

The patent-at-issue to Shionogi was directed to rosuvastatin calcium, the active ingredient in Crestor.  Nine separate defendants filed Abbreviated New Drug Applications (ANDAs), alleging that their generic versions of Crestor would not infringe the patent and that the patent was invalid and/or unenforceable.  At trial, the defendants, conceding infringement, argued that the patent was invalid based on structural obviousness, unenforceable due to inequitable conduct, and invalid due to improper reissue.  The district court found the patent to be valid and enforceable, and the defendants raised each of the above arguments on appeal. 

On appeal, the Federal Circuit dismissed the obviousness arguments, finding that a skilled artisan would not have been prompted to make the necessary changes to obtain rosuvastatin from the lead compound proposed by the defendants. 

Regarding inequitable conduct, the Federal Circuit found that while three undisclosed references proffered by the defendants were unquestionably known to Shionogi and material to patentability, the defendants failed to prove that Shionogi withheld these references with specific intent to mislead or deceive the Patent and Trademark Office (PTO), based largely on the panel’s deference to the district court’s determination of three key witnesses’ credibility. 

Addressing the improper reissue argument, the Court found that there was insufficient evidence to establish that Shionogi had intentionally omitted a claim specific to rosuvastatin in the original application and that Shionogi had acted in a timely manner once the error was discovered.  The Court noted that deceptive intent in the context of reissue required the same level of proof as deceptive intent in the context of inequitable conduct. 

Finally, the Federal Circuit found that one of the defendants, Apotex U.S., was a proper defendant.  Apotex U.S. had argued that while it submitted Apotex’s ANDA to the U.S. Food and Drug Administration (FDA), another company, Apotex Canada, had sent the Paragraph IV notification, which was an infringing act under Section 271(e)(2), and therefore Apotex U.S. could not be bound by any judgment of patent infringement.  The Court agreed with the finding of the district court that “a wholly-owned subsidiary of a foreign ANDA applicant, which signs an ANDA as the agent of its parent-applicant, and which intends to benefit directly if the ANDA is approved by participating in the manufacture, importation, distribution and/or sale of the generic drug [i]s subject to suit under §271(e) as the one who has ‘submitted’ the ANDA.”  Judge Plager wrote separately to clarify his opinion that Apotex U.S. was a proper defendant because Apotex U.S. had a financial interest in the drug that was the subject of the ANDA, i.e., Apotex U.S. was the party that would actually market and sell the drug in the United States.

Judge Mayer dissented from the decision, arguing that the patent should be held invalid for improper reissue, because the evidence demonstrated that Shionogi’s failure to specifically claim rosuvastatin was a deliberate choice made during the prosecution of the original application, and Shionogi made no attempt to seek reissue for over five years after the original patent issued.  Judge Mayer also noted that he believed Shionogi would have been found to commit inequitable conduct under the standard that existed prior to Therasense.