Federal Circuit Finds LUNESTA Patent Infringement Based on ANDA Product Description Not Avoided by Other Certifications

01 October 2013 PharmaPatents Blog

In Sunovion Pharmaceuticals, Inc. v. Teva Pharmaceuticals USA, Inc., the Federal Circuit reversed the district’s holding of no Lunesta® patent infringement that was based on a certification submitted to the court, and found infringement based on the product described in the Abbreviated New Drug Application (ANDA). In reaching its decision, the court upheld the district court’s construction of “consisting essentially of” that was based on arguments and evidence submitted during prosecution.

The Patent At Issue

The patent as issue was Sunovion’s U.S. Patent 6,444,673, which is listed in the Orange Book for Lunesta®. The court identified claim 1 as representative:

1. 6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine, or a pharmaceutically acceptable salt thereof, in the form of its dextrorotatory isomer and essentially free of its levorotatory isomer.

Thus, the patent is directed to eszopiclone, which is the (S)-enantiomer of the racemic drug known as zopiclone. As noted by the Federal Circuit, the FDA required “that each tablet of Lunesta® contain not more than … 0.3%” of the (R)-enantiomer.

The ANDA At Issue

The ANDA at issue was filed by Dr. Reddy’s Laboratories, Ltd. and Dr. Reddy’s Laboratories, Inc. (collectively “Reddy”). As noted by the Federal Circuit, Reddy originally “requested approval of generic eszopiclone products with ‘[n]ot less than 0.3% and [n]ot more than 1.0%’” of the (R)-enantiomer, but the FDA required Reddy to further limit the (R)-enantiomer content. Reddy therefore amended its ANDA to describe its product as having not more than 0.6% of the (R)-enantiomer.

The District Court Proceedings

The Federal Circuit summarized the district court proceedings on claim construction as follows:

Following a Markman hearing, the district court construed the claim term “essentially free” to mean “less than 0.25% of [the] levorotatory isomer.” …. The court found that there was no plain meaning for the disputed term and thus focused on intrinsic evidence, including the prosecution history of the patent …. The court held that Sunovion was bound by its own definition of the invention as containing less than 0.25% of the levorotatory enantiomer through a declaration submitted by named co-inventor Roussel and through amendments and arguments made during prosecution. ….

The Federal Circuit summarized the district court proceedings on infringement as follows:

The district court initially denied Reddy’s motion [for summary judgment of noninfringement] without prejudice, but permitted Reddy to file a renewed motion for summary judgment of noninfringement accompanied by a so-called “certification” that Reddy would not market an eszopiclone product contain¬ing less than 0.3% of the levorotatory isomer. …. Reddy subsequently submitted a declaration [(the “Cappuccino certification”)] to the district court from one of its employees vowing to the court, but not to the FDA, that Reddy would only market generic eszopiclone tablets containing 0.3-0.6% levorotatory isomer, notwithstanding that Reddy had not (and still has not) gained regulatory approval for products with that level of impurity. ….

The district court accordingly granted Reddy’s renewed motion for summary judgment of noninfringement, …. [based in the findings that] the eszopiclone products that Reddy presumes to market would likely be “outside the infringing range of less than 0.25% of levorotatory isomer” because of Reddy’s internal manufacturing guidelines and the Cappuccino certification in which it pledged to constrain the amount of levorotatory isomer to not less than 0.3%, despite the contrary representations made to the FDA in Reddy’s amended ANDA specification.

The Federal Circuit Decision

The Federal Circuit opinion was authored by Judge Lourie, and joined by Judges Reyna and Schall.

The Federal Circuit first considered the district court’s construction of the “essentially free of” clause. It affirmed the district court’s claim construction in view of the following findings:

  • There is no ordinary and customary meaning of the phrase “essentially free of”
  • The specification does not define (or even use) the phrase “essentially free of”
  • “The written description refers to the subject of the claimed invention merely as the dextrorotatory isomer of zopiclone, distinguished from the racemate, which is by definition a 50/50 mixture of the two enantiomers.”
  • During prosecution, “the applicants repeatedly and consist¬ently defined their claimed invention to be as exhibited by Example 1.”
  • During prosecution, the applicants submit¬ted a declaration attesting that “the ‘pure form’ of the dextrorotatory isomer of zopiclone ‘as described in Example 1’ contained ‘lower than 0.25%’ of the levorotatory isomer.

The court noted:

The applicants’ repeated and consistent attribution of the purity level of less than 0.25% levorotatory isomer to “the invention” and “the instant invention” thus gives meaning to the term “essentially free.”

Turning to the holding of noninfringement, the Federal Circuit explained the Hatch-Waxman infringement paradigm and stated:

[I]f a product that an ANDA applicant is asking the FDA to approve for sale falls within the scope of an issued patent, a judgment of infringement must necessarily ensue. …. What Reddy has asked the FDA to approve as a regulatory matter is the subject matter that determines whether infringement will occur, and the fact that Reddy either tells the court that its manufacturing guidelines will keep it outside the scope of the claims or has even filed a declaration in the court stating that it will stay outside the scope of the claims does not overcome the basic fact that it has asked the FDA to approve, and hopes to receive from the FDA, approval to market a product within the scope of the issued claims. In this case, Reddy’s request for approval of levorotatory amounts from 0.0-0.6% is within the scope of the “less than 0.25%” limitation of the ’673 patent claims. …..

Allowing Reddy to avoid infringement based on its unconventional and unenforceable “guarantee” when it is asking for and may receive FDA approval to market a product within the scope of the innovator’s patent, would be incompatible with the basic principles of patent law.

The Federal Circuit therefore reversed the finding of noninfringement.

You Can’t Have Your Sleep And Stay Up Late Too

It seems that Reddy was trying to have it both ways. On the one hand, Reddy sought to take advantage of the ANDA approval framework by relying on the approval of Lunesta®. On the other hand, Reddy sought to avoid the ANDA patent infringement framework by certifying that it would not infringe. The Federal Circuit decision here clarifies that the Hatch-Waxman Act does not work that way.

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