In Hatch-Waxman litigation that involved Abbreviated New Drug Applications (ANDAs) that were silent as to certain claimed limitations, the U.S. Court of Appeals for the Federal Circuit reversed a lower court’s conclusion that the ANDAs were infringing merely because the products could infringe the patents based on silence with respect to claimed limitations, finding that the evidence failed to show that the generic product sold or likely to be sold infringed the asserted claims. Ferring B.V. v. Watson Labs., Inc., Case Nos. 14-1377; -1416 (Fed. Cir., Aug. 22, 2014) (Lourie, J.).

Ferring sells branded tranexamic acid tablets, Lysteda®, for treatment of menorrhagia. Ferring owns three patents encompassing Lysteda, which are listed in the Orange Book and are directed to modified release formulations. Apotex and Watson filed ANDAs to sell generic versions of the tablets. Both defendants asserted that the patents would not be infringed by their ANDA product, and Watson alleged that the patents were invalid as obvious under § 103. Ferring sued for infringement of the patent under the provisions of the Hatch-Waxman Act. The asserted claims require about 650 mg of tranexamic acid, specified in-vitro dissolution release rate and specified amount of modified release material. Upon approval of its ANDA, Watson launched its generic product “at risk,” which Ferring did not move to enjoin.

The district court found that the asserted claims would not have been obvious because the prior art did not disclose a 650 mg dosage of tranexamic acid or suggest use of a higher dosage and, in fact, motivated in the opposite direction in view of prior art disclosure of dose-dependent increase in gastrointestinal side effects. The district court also found that Apotex’s actual product did not infringe the patents-in-suit based on its dissolution sample data, but concluded, under Sunovion that the absence of specific dissolution rate in the ANDA, corresponding to the asserted claims, permitted sale of an infringing product. Apotex amended its ANDA based on the court’s suggestion to specify a release rate outside the scope of the claims, which the U.S. Food and Drug Administration (FDA) approved and the court found non-infringing. Further, finding Watson’s ANDA submission to be an act of infringement, the district court concluded that Watson’s product infringed the patents, relying on dissolution rate of uncoated tablet cores and that of four out of the hundreds of coated commercial products tested. Watson’s ANDA did not disclose any dissolution data.  Watson appealed.

On appeal, the Federal Circuit emphasized that Glaxo rather than Sunovion applies when an ANDA is silent with respect to infringement, recommending analysis of relevant evidence including biobatch data and actual samples of the proposed product. For the patent holder to prove that a Glaxo-type ANDA is infringing, it must rely on evidence that the ANDA applicant would likely sell an infringing composition pursuant to an approved ANDA. The Court found that data regarding uncoated cores and outlier tablets could not prove infringement by a preponderance of evidence when the dissolution rate collected by both parties was outside the claim scope for an overwhelming majority of samples tested and was consistent with biobatch data reported in Watson’s ANDA itself.