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Trial Courts Cannot Look to the Prior Art Merely Listed in a Patent Specification to Provide Corresponding Structure for a Means-Plus-Function Limitation

March 24, 2010

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Last Month at the Federal Circuit - April 2010

Judges: Newman (concurring-in-part, dissenting-in-part), Lourie, Rader (author), Gajarsa, Moore

[Appealed from: E.D. Tex., Judge Clark]

In Pressure Products Medical Supplies, Inc. v. Greatbatch Ltd., No. 08-1602 (Fed. Cir. Mar. 31, 2010), the Federal Circuit vacated the district court’s finding of infringement and remanded the case for a determination of infringement under the correct claim construction.  In addition, the Court affirmed the district court’s denial of Greatbatch Ltd.’s (doing business as Enpath Medical, Inc. (“Enpath”)) motions for JMOL and leave to amend its answer.

Pressure Products Medical Supplies, Inc. (“Pressure Products”) is the owner of the patents-in-suit, U.S. Patent Nos. 5,125,904 (“the ’904 patent”) and 5,312,355 (“the ’355 patent”) (collectively “the Lee patents”).  These patents are directed to introducer sheaths for catheters and hemostatic valves at the proximal ends of the introducer sheaths.  Introducer sheaths facilitate the introduction and removal of catheters, and hemostatic valves prevent blood from leaking out of the body during the catheterization procedure.  The Lee patents disclose embodiments wherein both the introducer sheath and hemostatic valve include longitudinal score lines in order to enable the sheath and hemostatic valve to be split and two halves of each component peeled apart so that the sheath and valve may be removed while the catheter remains inserted in the body.  In reference to this feature, claim 1 of each of the Lee patents recites the disputed limitation:  “means for permitting removal of said hemostatic valve and introducer sheath from said lead or catheter disposed therethrough without requiring said introducer sheath and hemostatic valve to be removed from an end of said lead or catheter.”

During the trial, the trial judge supplemented the definition of the claim term “score lines” established by the magistrate judge at the Markman hearing.  Enpath disputed the supplementation, alleging that it was prejudicial for the district court to supplement the magistrate’s definition and that the supplement was unnecessary because the district court was not faced with the jury interpreting the “means for permitting removal” or “score line” limitations because the magistrate judge had already construed those terms. 

On appeal, the Federal Circuit did not consider the district court’s supplemental definition of the claim term during trial to present a fundamental procedural flaw that jeopardized the jury’s verdict.  The Court reasoned that the trial judge is in the best position to understand the entire context within which the claim term must be interpreted.  In addition, the Court noted that the trial judge supplemented the magistrate’s definition early enough in the trial to give Enpath an opportunity to consider the new construction and adjust its arguments to account for the change.  In further support of this ruling, the Court cited its own previous recognition that district courts may engage in a rolling claim construction, in which the court revisits and alters its interpretation of the claim terms as its understanding of the technology evolves.  In addition, the Federal Circuit noted that, when the parties raise an actual dispute regarding the proper scope of the claims, the court, not the jury, must resolve that dispute.

The Court held that the trial judge did, in fact, have a reason to supplement the magistrate’s definition of “score line” because the Markman order only defined “score line” in the context of dependent claims 4 through 8 of the ’904 patent, as the words “score line” do not appear in independent claim 1 of either Lee patent.  The trial judge’s supplementation provided a definition for the term “score line” in the context of the structure described in the specification corresponding to the means-plus-function limitation in claim 1 of the Lee patents, which the Markman order did not do.  Specifically, in each of the Lee patents, claim 1 includes the means-plus-function limitation “means for permitting removal,” which the trial judge found to correspond to the structure described in the specification as “score lines defined in the hemostatic valve and introducer sheath, and equivalents thereof.”  The Markman order did not address the term “score lines” in the context of its use in the specification.  Therefore, the Court held that the trial judge’s supplementation of the definition of “score lines” was warranted because it prevented the possibility that the jury would decide what this term means in the context of structure in the specification corresponding to the means-plus-function limitation in the claims.  Slip op. at 10.

Nevertheless, although the Court found that it was proper for the trial court to supplement the definition of “score line,” the Court did not agree that the trial court reached the proper definition in doing so.  Pressure Products argued that the trial court correctly construed the term “score lines” according to the doctrine of claim differentiation, alleging that the means-plus-function element of claim 1 must encompass structures other than score lines, namely, linear perforations, slits, slots, tabs, lines, severings, weakenings, or tears, as set forth in the trial judge’s definition.  However, many of these structures are disclosed only in prior art references that are mentioned in the patent. 

The Federal Circuit held that the district court erroneously used structures from the prior art references listed in the patent to provide a definition for score lines encompassing structures not disclosed expressly in the patent specification.  The Court noted that simply mentioning prior art references in a patent does not suffice as a specification description to give the patentee outright claim to all of the structures disclosed in those references.  The Court also explained that the trial judge did not need to include structure from the prior art in the definition in order to satisfy the doctrine of claim differentiation, because a means-plus-function claim element already includes structures other than the corresponding structure explicitly described in the specification, namely, equivalents of the corresponding structure.  Accordingly, the Court remanded for further proceedings in light of the proper construction of the term “score lines.”  Id. at 13.

In addition, the Court affirmed the district court’s denial of Enpath’s motion for JMOL.  The Court noted that there was ample support in the record for the jury’s verdict finding the Lee patents to be valid.  First, the Court noted that the Lee patents were entitled to the statutory presumption of validity, further noting that the ’904 patent underwent reexamination and thus was found to be patentable twice by the PTO.  Further, the Court pointed out that Pressure Products’ expert witness testified that the prior art does not disclose all of the claimed features of the Lee patents.  Also, Pressure Products submitted a declaration by the inventor of the prior art patent that was reviewed during the reexamination of the ’904 patent, stating that his patent does not disclose all of the claimed features of the Lee patents.  In addition, Pressure Products submitted secondary evidence of nonobviousness, including evidence of commercial success, long-felt need, skepticism of experts, and unexpected results, and Enpath did not rebut Pressure Products’ secondary evidence of nonobviousness.

In affirming the district court’s denial of the motion for JMOL, the Court reasoned that the trial record shows ample support for the jury’s judgment that the claimed invention would not have been anticipated or rendered obvious by prior art at the time of invention and that Enpath has not shown that the jury’s verdict on these points was unreasonable or based on insubstantial evidence.  Id. at 15.

The Court also affirmed the district court’s denial of Enpath’s motions to amend its answer.  Before trial, Enpath sought leave to amend its pleading to include an inequitable conduct defense.  Enpath filed its motions to amend its answer more than eighteen months after Pressure Products filed its complaint and over one year after Enpath filed its answer and counterclaims. 

The Court did not strictly apply Rule 16(b) because no scheduling order had passed as applied to Enpath.  The Court did, however, cite evidence that Enpath did not have good cause to amend.  Enpath based its inequitable conduct defense on a technical expert’s declaration, which was not available until November 2007, and, thus, Enpath argued that its motion to amend could not have been filed prior to November 2007.  However, the Federal Circuit agreed with the district court, which noted that the same technical expert produced declarations for the reexamination of the ’904 patent over a decade earlier in 1995 and that, further, Enpath received, as early as January 2007, a copy of the ’904 patent file wrapper, which included the 1995 declarations.  Id. at 17.

Moreover, the Court held that, regardless of whether Enpath met the requirements for filing an amended answer under Rule 16(b), Enpath was not entitled to amend its answer under the more liberal Rule 15(a).  The Federal Circuit agreed with the district court, which found that allowing Enpath to amend its pleadings “almost certainly” would have resulted in undue delay and would have “very likely” resulted in undue prejudice to Pressure Products.  Id.

The Court also noted that, since the district court’s ruling on Enpath’s motion to amend its answer, there have been significant opinions by the Federal Circuit requiring specific and demanding showings of evidence before a party may assert the defense of inequitable conduct.  Id. at 18-19 (citing Star Scientific, Inc. v. R.J. Reynolds Tobacco Co., 537 F.3d 1357, 1365 (Fed. Cir. 2008); Exergen Corp. v. Wal-Mart Stores, Inc., 575 F.3d 1312, 1329 n.5 (Fed. Cir. 2009)).  The Court expressed doubt that Enpath’s motion to amend would even satisfy these higher standards of proof to invoke the doctrine of inequitable conduct.  Therefore, the Court held that Enpath did not meet its high burden of showing that the district court abused its discretion in denying Enpath’s motion for leave to amend its answer.

Judge Newman authored a separate opinion, concurring-in-part and dissenting-in-part.  Joining the majority, Judge Newman concurred that the district court’s judgment on the issues of validity and inequitable conduct should be affirmed.  Judge Newman dissented, however, from the majority’s decision on infringement, reasoning that reversible error had not been shown in the district court’s claim construction, and the jury’s verdict was supported by substantial evidence. 

In particular, Judge Newman took issue with the majority’s conclusion that the district court should have ignored references that were incorporated by reference when construing claim limitations.  Judge Newman disagreed with the majority’s conclusion that Atmel Corp v. Information Storage Devices, Inc., 198 F.3d 1374, 1381 (Fed. Cir. 1999), prohibits a patentee from relying on an “incorporated” reference to describe the corresponding structure under § 112, ¶ 6.  Newman Dissent at 5.  Referring to the Court’s conclusion as “an incorrect generalization,” Judge Newman distinguished the Atmel case from the present circumstances by noting that, in Atmel, the specification did not describe any structure at all to perform the claimed function apart from the incorporated references, and that this description could not come solely from the incorporated reference.  Id.  In contrast, Judge Newman observed that the patent specifications in the present case fully described structures that perform the claimed function of removal of the valve and sheath, describing splittable sheaths of various forms, and explaining that there are many known ways of splitting or peeling plastic.  Judge Newman added that the incorporated references simply illustrated known structures that were known alternatives or equivalents to those in the specification.  By doing so, Judge Newman reasoned that patents may remain concise statements of what is new, not cumbersome repetitions of what is already known and readily provided by reference.


Summary authored by Jeremy T. Thissell, Esq.