Senju Pharmaceutical Co. v. Apotex Inc., 746 F.3d 1344

Senju filed suit in Delaware district court alleging infringement of claims 6 and 12-16 of Senju’s reexamined U.S. Patent No. 6,333,045 (the '045 patent) by Apotex’s Gatifloxacin ophthalmic solution under ANDA No. 79-084.
Apotex moved to dismiss, arguing claim preclusion barred the second action because Senju previously sued over the same patent before reexamination.
In the first action, the district court found original claims 1-3, 6-9 invalid as obvious, and final judgment followed in 2011; Senju’s claim 7 was specifically upheld invalid on that basis.
Senju requested reexamination; the PTO granted it, and in 2011 issued a reexamination certificate cancelling claims 1-3 and 8-11 and patenting amended claim 6, new claim 12, and new dependent claims 13-16.
Senju’s second suit filed November 28, 2011, during the post-remand period but before final judgment in the first action, asserted infringement of the reexamined claims 6 and 12-16.
The district court dismissed the second action as barred by claim preclusion, holding reexamined claims did not create a new cause of action because they were not broader than the original claims.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether reexamined claims create a new cause of action	Senju: reexamined claims may grant new rights not in original action.	Apotex: reexamined claims are within the same patent rights; no new action.	Reexamined claims do not create a new action; barred.
Whether products in both actions were essentially the same	Senju: differences in claims matter; may avoid preclusion.	Apotex: identical product described in ANDA No. 79-084; overlap supports preclusion.	Yes, the product overlap supports claim preclusion.
Whether the same patent rights were involved in both suits	Senju: reexamined claims can create rights not asserted earlier.	Apotex: reexamined claims cannot broaden beyond original and thus do not create new rights.	Reexamined claims do not create a new action; same patent rights for purposes of preclusion.
Impact of Aspex Eyewear on this case	Senju: Aspex requires detailed comparison of reexamined vs original claims to determine overlap.	Apotex: Aspex supports treating reexamined claims as non-new if not broader.	Aspex supports no new grounds to assert infringement; reexamined claims here are not a new action.
Whether reexamination can ever yield a material difference creating a new action	Senju: possible, requiring remand to compare material differences.	Apotex: reexamination cannot broaden claims; no new action.	Not necessary to opine; no material difference shown here; preclusion applies.

Acumed LLC v. Stryker Corp., 525 F.3d 1319 (Fed. Cir. 2008) (define overlap-based preclusion analysis in patent cases)
CoreStates Bank, N.A. v. Huls Am., Inc., 176 F.3d 187 (3d Cir. 1999) (three-factor test for claim preclusion in Third Circuit)
Lawlor v. Nat'l Screen Serv. Corp., 349 U.S. 322 (Supreme Court 1955) (final judgment bars claims that could have been raised)
Kearns v. Gen. Motors Corp., 94 F.3d 1553 (Fed. Cir. 1996) (each patent asserted generally constitutes a separate cause of action)
Aspex Eyewear, Inc. v. Marchon Eyewear, Inc., 672 F.3d 1335 (Fed. Cir. 2012) (reexamined claims not broader than original do not create new rights)
Superior Fireplace Co. v. Majestic Prods. Co., 270 F.3d 1358 (Fed. Cir. 2001) (presumption of validity applies to reexamined claims)
Superior Fireplace Co. v. Majestic Prods. Co., 540 F.3d 1358 (Fed. Cir. 2001) (reexamination claims are limited by original patent)
C.I.R. v. Sunnen, 333 U.S. 591 (Supreme Court 1948) (final judgments bind as to all matters raised or that could have been raised)
Cromwell v. Sac Co., 94 U.S. 351 (Supreme Court 1876) (operational framework for res judicata)
Transclean Corp. v. Jiffy Lube Int'l, Inc., 474 F.3d 1298 (Fed. Cir. 2007) (same patent and same accused device support preclusion)