Senju Pharmas. Co., Ltd. v. Apotex Inc. (Fed Cir)

Case Name: Senju Pharmas. Co., Ltd. v. Apotex Inc., No. 2013-1027, 2014 U.S. App. LEXIS 5877 (Fed. Cir. Mar. 31, 2014) (Circuit Judges Newman, Plager, and O’Malley presiding; Opinion by Plager, J.; Dissent by O’Malley) (appeal from D. Del., Robinson, J.)

Drug Product and Patent(s)-in-Suit: Zymar^® (gatifloxacin ophthalmic solution); U.S Patent No. 6,333,045 (“the ’045 patent”) 

Nature of the Case and Issue(s) Presented: The ’045 patent claims the combination of gatifloxacin with disodium edetate (“EDTA”). The ’045 patent originally issued in December 2001. In July 2007, Apotex submitted an ANDA requesting approval to manufacture, market, and sell a generic version of the gatifloxacin ophthalmic solution covered by the ’045 patent. In November 2007, Senju sued Apotex claiming patent infringement. The district court held a bench trial and found the asserted claims invalid as obvious. Senju then filed a motion for a new trial or to amend the district court’s judgment. In December 2011, the district court again concluded that the asserted claims were invalid on the ground of obviousness, and it entered final judgment in the case. In the gap between the district court’s issuance in June 2010 of its findings of fact and conclusions of law and its entry of final judgment in the case in December 2011, Senju filed a request for reexamination of certain claims of the ’045 patent. The USPTO granted reexamination in April 2011, and in response to an initial rejection on the ground of obviousness, Senju amended certain claims to include several additional limitations, including the amount of gatifloxacin, the amount of EDTA, and the pH. Senju also added a new independent claim with similar limitations. In October 2011, the USPTO issued a reexamination certificate.

On November 28, 2011, still in the gap prior to the entry of final judgment in the first action, Senju filed a new action against Apotex, seeking a declaratory judgment that Apotex’s manufacture, use, or sale of gatifloxacin ophthalmic solution infringed the claims set forth in the reexamination certificate of the ’045 patent. Apotex filed a Rule 12(b)(6) motion to dismiss this second suit, arguing that Senju was precluded from asserting the reexamined ’045 patent in the second action under the doctrine of claim preclusion. The district court agreed that Senju had asserted the same cause of action in its second action that it had asserted in its first action. Senju appealed and the Federal Circuit affirmed.

Why Apotex Prevailed:  The issue on appeal was whether Senju’s first and second actions were based on the same cause of action. In its first suit, Senju alleged infringement based on Apotex’s ANDA No. 79-084 and its described gatifloxacin ophthalmic solution. In its second suit, Senju requested a declaratory judgment of infringement based on Apotex’s submission of the same ANDA. Thus, both actions involve the same product. Because the product in the second action completely overlaps with the product in the first action, there is on that basis no new cause of action.

The more difficult analysis is “whether the same patent, or more precisely the same patent rights, were involved in both suits. Relying in large part on its decision in Aspex Eyewear, Inc. v. Marchon Eyewear, Inc., 672 F.3d 1335, the Federal Circuit held that claims that emerge from reexamination do not in and of themselves create a new cause of action that did not exist before. Because a so-called “reexamined patent” is the original patent; it has just been examined another time as indicated in its reexamination certificate. Reexamination does not involve the filing of a new patent application or the issuance of a new patent. Moreover, any amendment that occurs during reexamination is statutorily constrained. Therefore, the Federal Circuit held that Senju’s second suit against Apotex was barred on the principles of claim preclusion.

Judge O’Malley’s dissent took issue with the majority because the reexamined claims that issued were presumptively valid and, unlike the invalid original claims, may have provided Senju with actionable patent rights. Moreover, Judge O’Malley took issue with the majority’s heavy reliance on Aspex because in that case none of the original claims had been invalidated and the Federal Circuit did not assess whether entirely new patent rights might have emerged from reexamination patent rights.