Senju Pharm. Co. v. Apotex, Inc.

Case Name: Senju Pharm. Co. v. Apotex, Inc., Civ. No. 11-1171-SLR, 2012 U.S. Dist. LEXIS 132219 (D. Del. Sept. 17, 2012) (Robinson, J.)

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

Nature of the Case and Issue(s) Presented:  This is the second case that plaintiffs filed against Apotex asserting infringement of the ’045 patent.  In the first case, the court held that the asserted claims of the ’045 patent were invalid as obvious.  Before the entry of final judgment, plaintiff filed a petition for reexamination based on Apotex’s invalidity arguments and the court’s ruling.  During reexamination, plaintiffs cancelled most of the original claims and submitted new claims that contained many of the dependent limitations found in the original claims, but which were now all in one independent claim.  When the PTO served a notice of intent to issue a reexamination certificate, plaintiffs, for the first time, informed the Court of the existence of the reexamination.

Plaintiffs then filed a complaint for patent infringement against Apotex based on its prior ANDA filing.  Apotex moved to dismiss plaintiffs’ complaint under Fed. R. Civ. P. 12(b)(6) arguing that the claims should be dismissed on the basis of claim preclusion.  In particular, Apotex argued that the claims were the same or substantially similar to the original claims.  In response, plaintiffs argued that the claims were new and could not have been asserted in the prior litigation, and claim preclusion should not apply.  The court agreed with Apotex.

Why Apotex Prevailed:  The Court found that each patent gives rise to a cause of action, and not each claim of a patent.  Applying Federal Circuit law, the only issue in dispute was whether the claims being asserted in the new action were the same or substantially similar to the claims asserted in the first action. 

The court found that the new claims were merely rewrites of the original claims.  In particular, the new claims were combinations of limitations that were present in the original claims.  Thus, the court found that the new claims were not broader in scope than the original claims, and if anything, they were narrower than the original claims.  Because the plaintiffs could have sought a narrowing interpretation of the original claims in the first action that would have been the same or substantially similar to the new claims, the court found that the new claims were, in fact, not new.  Thus, the Plaintiffs cause of action was precluded by claim preclusion.