"Because we conclude that the district court committed clear error in finding that Stevens acted with deceptive intent, we need not address Cancer Research's argument that the district court also erred in finding the withheld data highly material, and we reverse the district court's decision holding the '291 patent unenforceable for inequitable conduct.
For the foregoing reasons, we reverse the district court's decision holding the '291 patent unenforceable for prosecution laches and inequitable conduct.
Dissenting opinion filed by Circuit Judge PROST.
PROST, Circuit Judge, dissenting.
I respectfully dissent. In my view, the majority opinion seriously errs in reversing the district court's findings and conclusions that U.S. Patent No. 5,260,291 ("'291 patent") is unenforceable on the grounds of both prosecution laches and inequitable conduct. In doing so, the majority propounds a new and unsupportable legal standard for prosecution laches. With regard to inequitable conduct, the majority not only creates a new evidentiary standard, but it also ignores virtually unassailable credibility findings made by the district court after a four-day bench trial. I address each in turn below.
I. Prosecution Laches
The majority appears to not take issue with the district court's findings and conclusion that the patentee's almost decade-long 735*735 delay in prosecuting its application— caused by filing eleven continuation applications, abandoning ten of those applications, and obtaining nearly two years' worth of time extensions merely to file continuation applications rather than responses to the Office Actions—was unreasonable. Despite Cancer Research Technology Limited and Schering Corporation's (collectively, "Cancer Research") excuses justifying the delay, the information eventually used to overcome the examiner's initial rejection was contained in the application as originally filed ten years earlier. The district court carefully rejected all of the patentee's excuses for its delay, ultimately concluding that the applicants did not prosecute the application until it became commercially advantageous to do so.
Instead, the majority rejects the legal standard the district court applied. The district court concluded that under Symbol Technologies, Inc. v. Lemelson Medical, 422 F.3d 1378 (Fed.Cir.2005) ("Symbol Techs. II"), prosecution laches does not require a showing of intervening rights, but rather turns on whether under the totality of the circumstances Cancer Research's delay was unreasonable and unexplained. See Cancer Research Tech. v. Barr Labs., Inc., 679 F.Supp.2d 560, 572-73 (D.Del.2010). Besides rejecting this standard, the majority says that in order to establish prosecution laches (1) prejudice to the alleged infringer must be shown, and (2) that prejudice requires that "either the accused infringer or others invested in, worked on, or used the claimed technology during the period of delay." Maj. Op. at 729 (emphasis added); see also id. at 732 ("Barr has failed to establish either that it or that others developed or invested in temozolomide or any other claimed tetrazine compound between 1982 and 1991, the period of delay. Accordingly, Barr cannot establish prosecution laches as a matter of law....").
First, I think the district court got it right because I do not agree with the majority that a showing of intervening rights, i.e. prejudice, is compelled by our precedent. Moreover, even if one could construe the case law as requiring prejudice, there is no basis, in the relevant case law or otherwise, for the majority's further temporal limitation that the prejudice exists during the period of delay.
Shifting the inquiry regarding prosecution laches from Cancer Research's own conduct to the conduct of the party invoking the defense ignores that prosecution laches is an equitable defense. Neither the Supreme Court nor this court has required a defendant to establish prejudice to assert prosecution laches. Indeed, in Woodbridge v. United States, the Court held that a plaintiff's willful or negligent postponement in obtaining patent rights alone can result in forfeiture. 263 U.S. 50, 57, 44 S.Ct. 45, 68 L.Ed. 159 (1923) (quoting Kendall v. Winsor, 62 U.S. (21 How.) 322, 329, 16 L.Ed. 165 (1858), for the proposition that an inventor "`may forfeit his rights as an inventor by a willful or negligent postponement of his claims, or by an attempt to withhold the benefit of his improvement from the public until a similar or the same improvement should have been made and introduced by others'" (emphasis added)). Our precedent is no 736*736 more restrictive. Recognizing that prosecution laches is an equitable doctrine, we have declined to "set forth any firm guidelines for determining when such laches exists." Symbol Techs. II, 422 F.3d at 1385. Laches may be triggered by "the totality of the circumstances, including the prosecution history of all of a series of related patents and overall delay in issuing claims." Id. at 1386. And we have specifically indicated that "repetitive refilings that demonstrate a pattern of unjustifiably delayed prosecution" "for the business purpose of delaying ... issuance [of the patent]"—an apt description of Cancer Research's behavior during the prosecution of the '291 patent—supports a finding of laches. Id. at 1385-86."