United States Court of Appeals for the Federal Circuit
2006-1334, -1452
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA,
ABBOTT MOLECULAR, INC., and ABBOTT LABORATORIES, INC.,
Plaintiffs-Appellants,
v.
DAKOCYTOMATION CALIFORNIA, INC.,
Defendant-Appellee.
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2007-1202
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA,
ABBOTT MOLECULAR, INC., and ABBOTT LABORATORIES, INC.,
Plaintiffs-Appellants,
v.
DAKO A/S,
and DAKO NORTH AMERICA, INC.,
Defendants-Appellees.
James F. Hurst, Winston & Strawn, LLP, of Chicago, Illinois, argued for plaintiffs-
appellants. On the briefs were Lynn H. Pasahow, Heather N. Mewes, Carolyn C.
Chang, and C.J. Alice Chuang, Fenwick & West, LLP, of Mountain View, California. Of
counsel was Virginia K. DeMarchi.
Thomas H. Jenkins, Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P., of
Washington, DC, argued for all defendants-appellees. With him on the briefs were
Anthony C. Tridico, of Washington, DC, and Tina E. Hulse and David C. Hoffman, of
Palo Alto, California. On the brief for defendant-appellee Dakocytomation California,
Inc. was Richard J. Smith, of Palo Alto, California.
Appealed from: United States District Court for the Northern District of California
Judge Marilyn H. Patel
United States Court of Appeals for the Federal Circuit
2006-1334, -1452
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA,
ABBOTT MOLECULAR, INC., and ABBOTT LABORATORIES, INC.,
Plaintiffs-Appellants,
v.
DAKOCYTOMATION CALIFORNIA, INC.,
Defendant-Appellee.
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2007-1202
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA,
ABBOTT MOLECULAR, INC., and ABBOTT LABORATORIES, INC.,
Plaintiffs-Appellants,
v.
DAKO A/S,
and DAKO NORTH AMERICAN, INC.,
Defendants-Appellees.
Appeal from the United States District Court for the Northern District of
California in Case No. 05-CV-03955, Judge Marilyn Hall Patel.
_____________________
DECIDED: February 28, 2008
_____________________
Before MAYER, LOURIE, and PROST, Circuit Judges.
Opinion for the court filed by Circuit Judge LOURIE. Opinion dissenting in part filed by
Circuit Judge PROST.
LOURIE, Circuit Judge.
The Regents of the University of California and Abbott Molecular Inc. and Abbott
Laboratories Inc. (collectively referred to as “appellants”) appeal from two decisions of
the United States District Court for the Northern District of California. Appellants first
appeal the district court’s denial of their motion for a preliminary injunction enjoining
Dako A/S and Dako North American, Inc. (“Dako”) from manufacturing and selling its
HER2 FISH pharmDXTM kit (“HER2 kit”), which appellants allege infringe the patents in
suit, viz., U.S. Patents 5,447,841 (“the ’841 patent”) and 6,596,479 (“the ’479 patent”).
Appellants also filed an interlocutory appeal from the district court’s decision granting in
part summary judgment of noninfringement of these patents. Because we conclude that
the district court correctly construed the term “heterogeneous mixture of labeled unique
sequence nucleic acid fragments,” erred in its construction of “morphologically
identifiable cell nucleus,” and erred by concluding that appellants were barred by the
doctrine of prosecution history estoppel, we affirm in part, reverse in part, and remand
for further proceedings.
BACKGROUND
A. Background on Technology
The cells of living organisms contain chromosomes—structures in the cell
nucleus that are composed in part of deoxyribonucleic acid (“DNA”). DNA is a complex
molecule that encodes the genetic information of an organism. In order for a cell to
replicate and divide, it undergoes a process known as mitosis. There are two main
phases in the cell-division cycle—metaphase and interphase. During metaphase, the
chromosomes are condensed and are thus visible with a microscope. At this stage of
2006-1334, -1452, 2007-1202 2
mitosis, the condensed chromosomes align in the middle of the cell before dividing into
two daughter cells. That phase is relatively short-lived, as the rest of the cycle is spent
in interphase. During interphase, the chromosomes are not visible with a microscope
because they are not condensed and are spread throughout the nucleus.
The inventions claimed in the patents in suit are directed to improved “methods
for identifying and classifying chromosomes” in order to detect chromosomal
abnormalities. ’841 patent col.1 ll.21-22. 1 Such abnormalities “are associated with
genetic disorders, degenerative diseases, and exposure [sic] to agents known to cause
degenerative diseases,” such as cancer. Id. col.1 ll.23-26. There are three general
types of chromosomal abnormalities, viz., extra or missing individual chromosomes,
extra or missing portions of a chromosome, or chromosomal rearrangements. Id. col.1
ll.34-36. While a normal human cell contains twenty-three pairs of chromosomes, the
genetic disorder known as Down syndrome, for example, is caused by an extra copy of
chromosome 21. Id. col.1 ll.45-46.
Several problems existed in the prior art with respect to screening chromosomes.
First, procedures in the prior art were limited to and required that chromosomes be in
the metaphase phase of the cell cycle. Those procedures required use of metaphase
chromosomes because it was not “possible to visualize nonmetaphase, or interphase
chromosomes due to their dispersed condition in the cell nucleus.” Id. col.2 ll.19-23.
The procedures used cytological techniques to stain the chromosomes, thereby
revealing “a longitudinal segmentation into entities generally referred to as bands.” Id.
1
The ’479 patent is a divisional of the ’841 patent, and has a specification that
is nearly identical to that of the ’841 patent. For ease of reference, throughout the
opinion we will cite the ’841 patent when referencing the common specification.
2006-1334, -1452, 2007-1202 3
col.2 ll.25-27. Banding analysis, however, required “cell culturing and preparation of
high [q]uality metaphase spreads, which is extremely difficult and time consuming, and
almost impossible for tumor cells.” Id. col.2 ll.36-39.
Second, other prior art techniques, which used probes comprised of DNA and
RNA fragments for gene mapping, were limited by the nonspecificity of that technique.
Those probes “comprise labeled fragments of single stranded or double stranded DNA
or RNA which are hybridized to complementary sites on chromosomal DNA.” Id. col.2
ll.57-60. The hybridization process of the labeled probes to the target chromosomal
DNA requires the denaturation, or the unraveling, of the double-stranded nucleic acids
by heating or some other means. Id. col.3 ll.4-17. That process then requires several
additional steps. A problem associated with that technique, however, was the
nonspecificity of the staining reagents due to repetitive nucleotide sequences that were
present throughout the chromosomes. Id. col.4 ll.47-52. Nucleotide sequences are
generally divided into three different categories based on their frequency: highly
repetitive (or satellite DNA), which is located in the centromeric region of the
chromosome; middle-repetitive, which is generally interspersed among unique
sequences; or unique. Id. col.4 ll.27-30. The presence of repetitive sequences “greatly
reduces the degree of chromosome-specificity of the staining reagents of the invention,
particularly in genomes containing a significant fraction of repetitive sequences, such as
the human genome.” Id. col.8 ll.40-44. Labeled probes would not only hybridize with
the target chromosomal DNA, but with repetitive sequences as well, thereby producing
unacceptable false-positive results.
2006-1334, -1452, 2007-1202 4
In light of those problems, the patentees sought to employ a staining technique
that “open[ed] up the possibility of rapid and highly sensitive detection of chromosomal
abnormalities in both metaphase and interphase cells using standard clinical and
laboratory equipment.” Id. col.5 ll.29-33. To increase the specificity of the staining
reagents, the patents at issue state that it is “desirable to disable the hybridization
capacity of repetitive sequences.” Id. col.4 ll.47-48. The specification discloses three
ways to disable the hybridization capacity of the repetitive sequences, consisting of
blocking, selective removal, and screening of repetitive sequences. The ’841 patent
claims are directed to blocking the repetitive sequences. Claim 1 of the ’841 patent
reads as follows:
1. A method of staining target chromosomal DNA comprising:
(a) providing 1) labeled nucleic acid that comprises fragments which are
substantially complementary to nucleic acid segments within the
chromosomal DNA for which detection is desired, and 2) blocking nucleic
acid that comprises fragments which are substantially complementary to
repetitive segments in the labeled nucleic acid; and
(b) employing said labeled nucleic acid, blocking nucleic acid, and
chromosomal DNA in in situ hybridization so that labeled repetitive
segments are substantially blocked from binding to the chromosomal
DNA, while hybridization of unique segments within the labeled nucleic
acid to the chromosomal DNA is allowed, wherein blocking of the labeled
repetitive segments is sufficient to permit detection of hybridized labeled
nucleic acid containing unique segments, and wherein the chromosomal
DNA is present in a morphologically identifiable chromosome or cell
nucleus during the in situ hybridization.
’841 patent, claim 1 (emphases added). During prosecution of the ’841 patent, the
patentees indicated that the claims of the patent were limited to the blocking
embodiment. They further indicated that claims to the other major embodiment of
2006-1334, -1452, 2007-1202 5
disabling the hybridization capacity, i.e., by removal of the repetitive sequences, would
be pursued in another patent application. That application resulted in the ’479 patent.
Claim 1 of the ’479 patent reads as follows:
1. A method of staining target interphase chromosomal DNA to detect an
extra or missing portion or portions of a chromosome, or a translocation or
an inversion of a portion or portions of a chromosome, the method
comprising:
(a) providing a heterogeneous mixture of labeled unique sequence nucleic
acid fragments which are substantially complementary to nucleic acid
segments within the interphase chromosomal DNA for which detection is
desired and are designed to allow detection of an extra or missing portion
or portions of a chromosome, or a translocation or an inversion of a
portion or portions of a chromosome;
(b) employing the heterogeneous mixture and interphase chromosomal
DNA in in situ hybridization to permit detection of labeled nucleic acid
fragments which are hybridized to interphase chromosomal DNA, wherein
the chromosomal DNA is present in a morphologically identifiable cell
nucleus during the in situ hybridization; and
(c) detecting the labeled nucleic acid fragments which are hybridized to
the interphase chromosomal DNA to determine whether an extra or
missing portion or portions of a chromosome, or a translocation or an
inversion of a portion or portions of a chromosome is present in the target
interphase chromosomal DNA.
’479 patent claim 1 (emphases added). The ’479 patent does not refer to the blocking
method. Instead, the claimed invention of the ’479 patent employs compositions that
are comprised of “a heterogeneous mixture of labeled unique sequence nucleic acid
fragments” that excludes repetitive sequences. Thus, the invention of the ’479 patent
employs the method of removing or screening repetitive sequences from the
heterogeneous mixture in order to disable the hybridization capacity of repetitive
sequences—in contrast to using blocking nucleic acid, as claimed in the ’841 patent.
2006-1334, -1452, 2007-1202 6
B. Procedural Background
On September 29, 2005, appellants, who are the owner and exclusive licensee of
the patents in suit, filed a complaint for patent infringement against Dako. On October
14, 2005, appellants filed a motion for preliminary injunction seeking to prohibit Dako
from manufacturing and selling its HER2 kit. The court denied appellants’ motion on
March 10, 2006. In denying the motion, the court concluded that appellants failed to
show a likelihood of success on the merits of their infringement claim under the ’479
patent based on, inter alia, its claim construction of two claim limitations, viz.,
“morphologically identifiable chromosome or cell nucleus” and “heterogeneous mixture
of labeled unique sequence nucleic acid fragments.” The court also based its
conclusion on appellants’ failure to show a likelihood of success that the accused
product met the “blocking nucleic acid” limitation of the ’841 patent under the doctrine of
equivalents.
On March 30, 2006, appellants appealed the district court’s denial of the
preliminary injunction. While that appeal was pending, the district court issued another
order on May 17, 2006, amending the basis for its denial of the preliminary injunction.
Specifically, the district court amended its basis for rejecting appellants’ proposed
construction of the term “heterogeneous mixture of labeled unique sequence nucleic
acid fragments.” In the original order denying the preliminary injunction, the district
court rejected appellants’ proposed construction of that term, which only appears in the
’479 patent, based on its conclusion that the ’841 patent is prior art to the ’479 patent,
and that adopting appellants’ proposed construction would likely render the ’479 patent
invalid. The court amended “its previous order to the extent it improperly cite[d] 35
2006-1334, -1452, 2007-1202 7
U.S.C. § 102 as the basis for questioning the validity of the claims of the ’479 patent” in
light of the ’841 patent, and instead stated that the ’479 patent would likely be rendered
invalid under the doctrine of nonstatutory (obviousness) double patenting. Appellants
then appealed from the court’s amended order, and both preliminary injunction appeals
were consolidated for briefing and oral argument.
While the appeals were pending, Dako moved for summary judgment of
noninfringement. Prior to ruling on that motion, the district court held a Markman
hearing and construed certain claim limitations. On July 31, 2006, the court granted
summary judgment of noninfringement of the ’479 patent as to all of the accused
products based on its construction of the “heterogeneous mixture” limitation. The court
further granted summary judgment of noninfringement on the ’841 patent as to two of
Dako’s products, viz., the HER2 kit and TOP2A kit, upon concluding that appellants
were barred from asserting infringement of the “blocking nucleic acid” limitation under
the doctrine of equivalents. The court also denied summary judgment on the ’841
patent as to the remaining twenty accused products. The court did not address whether
Dako’s products met the “morphologically identifiable” limitation—a claim limitation that
was at issue in the preliminary injunction motion.
The parties jointly filed a motion to certify for immediate appeal the district court’s
summary judgment order under 28 U.S.C. § 1292(b) and to stay the proceedings. The
district court granted the motion on December 15, 2006, and on February 14, 2007, we
granted permission to appeal the interlocutory order. While we have not generally
certified motions for interlocutory appeal of claim construction, we determined that it
was especially desirable in this case in view of the pendency of the related appeal on
2006-1334, -1452, 2007-1202 8
the denial of the preliminary injunction based on some of the same issues. At oral
argument, the parties agreed that the preliminary injunction appeals and the summary
judgment appeal should be considered together in light of the overlapping issues that
are before us. We have jurisdiction pursuant to 28 U.S.C. § 1292(c)(1).
DISCUSSION
A. Standard of Review
Appellants raise three issues in their combined appeal from the preliminary
injunction and summary judgment orders. Two issues concern claim construction and
the other concerns prosecution history estoppel. We review claim construction, which is
an issue of law, Markman v. Westview Instruments, Inc., 52 F.3d 967, 970-71 (Fed. Cir.
1995) (en banc), de novo. Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1456 (Fed.
Cir. 1998) (en banc). Whether the district court erred in its application of prosecution
history estoppel to limit the effect of the doctrine of equivalents is also a question of law
that is reviewed de novo. Pharmacia & Upjohn Co. v. Mylan Pharms., Inc., 170 F.3d
1373, 1376 (Fed. Cir. 1999).
B. Issues Presented in the Summary Judgment Appeal 2
1. Construction of “heterogeneous mixture of labeled unique sequence
nucleic acid fragments”
In both the preliminary injunction and summary judgment appeals, appellants
argue that the district court erred in its construction of the claim limitation
“heterogeneous mixture of labeled unique sequence nucleic acid fragments,” a limitation
2
We first address the issues raised in the summary judgment appeal, as our
decision concerning the construction of “heterogeneous mixture” in that case has a
dispositive impact on the preliminary injunction appeal.
2006-1334, -1452, 2007-1202 9
that is required by every claim of the ’479 patent. The court construed that language to
mean “heterogeneous mixture of labeled nucleic acid fragments that includes only
unique sequence fragments,” whereas Dako’s kits contain repetitive sequences.
Appellants assert that the court erred by interpreting that language to mean that the
heterogeneous mixture excludes repetitive sequences. They assert that that
construction is contrary to the fact that the dependent claims of the patent clearly
require repetitive sequences. Appellants further argue that the district court erred by
relying on the prosecution history in support of its construction. According to appellants,
the term “unique sequence” was not added to the claim to limit the scope of the
heterogeneous mixture, as the court concluded. Rather, it was added to clarify that the
invention related to the detection of unique sequences, as opposed to the detection of
repetitive sequences as taught in the prior art.
In response, Dako argues that the intrinsic evidence supports the district court’s
construction. According to Dako, the claim language supports a construction that
excludes repetitive sequences, notwithstanding the dependent claims, because the
specification supports that construction in statements and embodiments and in light of
the prosecution history of the ’479 patent. In addition, Dako argues that the doctrine of
claim differentiation is not an absolute rule. Where construction of an independent
claim leads to a clear conclusion inconsistent with a dependent claim, the doctrine of
claim differentiation must yield.
In its initial order denying preliminary injunctive relief, the court concluded that
the heterogeneous mixture excludes repetitive sequences in light of the ’841 patent,
which the court characterized as prior art to the ’479 patent. The court reasoned that
2006-1334, -1452, 2007-1202 10
appellants’ construction, which contemplates the use of both unique and repetitive
sequences, raised “serious concerns about the [appellants’] ability to simultaneously
preserve validity and establish infringement with respect to the claim of the ’479 patent.”
Regents of Univ. of Cal. v. DakoCytomation Cal., Inc., No. 05-CV-03955, 2006 WL
618769, at *9 (N.D. Cal. Mar. 10 2006). Thus, the court rejected appellants’ proposed
construction upon concluding that it would likely render the patent invalid under 35
U.S.C. § 102(b). The court’s reasoning, however, was erroneous because the ’479
patent is a division of the ’841 patent and claims the priority of the filing date of the ’841
patent. See 35 U.S.C. § 120. As such, the court erred in characterizing the ’841 patent
as prior art, and thus erred in concluding that the ’841 patent would likely render the
’479 patent invalid if appellants’ construction had been adopted.
After realizing its error, the district court issued an amended preliminary
injunction order, relying on a new basis for rejecting appellants’ proposed construction.
The court reasoned that that construction would likely render the ’479 patent invalid
based on nonstatutory (obviousness) double patenting in view of the ’841 patent.
Appellants, however, had previously filed a terminal disclaimer, which cures such a
double patenting rejection. Geneva Pharms., Inc. v. GlaxoSmithKline PLC, 349 F.3d
1373, 1378 (Fed. Cir. 2003). Thus, the court erred by rejecting appellants’ construction
on that basis as well.
Although the district court erred in its reasoning as set forth above, we
nonetheless will affirm the court’s construction of the heterogeneous mixture limitation.
The court correctly evaluated the prosecution history and determined the proper claim
construction. We also agree with the court’s conclusion set forth in its summary
2006-1334, -1452, 2007-1202 11
judgment decision that the patentees disclaimed embodiments that include repetitive
sequences during the prosecution of the ’479 patent. Thus, the district court was
correct in concluding that the accused products, which employ a mixture that includes
repetitive sequences, do not infringe the ’479 patent.
It is a truism that the claims of a patent define the invention that is claimed, but
“the prosecution history can often inform the meaning of the claim language by
demonstrating how the inventor understood the invention and whether the inventor
limited the invention in the course of prosecution, making the claim scope narrower than
it would otherwise be.” Phillips v. AWH Corp., 415 F.3d 1303, 1317 (Fed. Cir. 2005) (en
banc).
The prosecution history in the present case sheds decisive light on the scope of
the disputed claim term. As originally filed, the divisional application that resulted in the
’479 patent included a single claim. That claim, claim 17, read:
17. A method of staining chromosomal DNA of a particular chromosome
type or portion thereof, or a particular group of chromosome types, the
method comprising the steps of:
providing a heterogeneous mixture of labeled nucleic acid fragments,
substantial portions of each labeled nucleic acid fragment in the
heterogeneous mixture having base sequences substantially
complementary to base sequences of the chromosomal DNA; and
reacting the heterogeneous mixture with the chromosomal DNA by in situ
hybridization.
Supp. J.A. 6592. Notably, the original claim did not include the phrase “unique
sequence.”
In April 1996, the examiner issued three separate rejections, including an
enablement rejection under § 112, first paragraph; an indefiniteness rejection under
2006-1334, -1452, 2007-1202 12
§ 112, second paragraph; and an anticipation rejection in view of three prior art
references, viz., Landegent et al., Montgomery et al., and Cannizzaro et al. To
overcome those rejections, the patentees canceled claim 17 and submitted a new
independent claim, claim 18, as well as several dependent claims. Claim 18 read:
18. A method of staining target interphase chromosomal DNA to detect
amplifications, deletion, and rearrangements comprising:
(a) providing a heterogeneous mixture of labeled unique sequence nucleic
acid fragments which are substantially complementary to nucleic acid
segments within the interphase chromosomal DNA for which detection is
desired; and
(b) employing the heterogeneous mixture and interphase chromosomal
DNA in in situ hybridization to permit detection of labeled nucleic acid
fragments which are hybridized to interphase chromosomal DNA, wherein
the chromosomal DNA is present in a morphologically identifiable cell
nucleus during the in situ hybridization.
Supp. J.A. at 6650-51 (emphases added). Thus, the patentees added the “unique
sequence” limitation, as well as other limitations regarding interphase chromosomal
DNA and a morphologically identifiable cell nucleus. Although the patentees did not
expressly state whether the “unique sequence” limitation was added in response to any
particular rejection, given the patentees’ arguments accompanying the amendment, as
well as previous statements patentees made during the prosecution of the ’841 patent,
the term “unique sequence” was clearly added to overcome the enablement rejection.
When issuing the enablement rejection, the examiner stated that “[a]s worded,
there is no specificity practice in the actual claim steps that would result in the staining
of the target only without so much background that the desired target nucleic acid would
be [obscured].” Thus, the examiner recognized that original claim 17 failed to include a
limitation directed toward reducing the nonspecific binding of repetitive sequences—a
2006-1334, -1452, 2007-1202 13
key problem in the prior art, as disclosed in the specification. The patentees, however,
were able to overcome the enablement rejection by limiting the heterogeneous mixture
to unique sequences. Indeed, by restricting the heterogeneous mixture to labeled
probes of unique sequences, the problem resulting from probes binding to the repetitive
sequences would not arise.
That conclusion is supported by the patentees’ earlier decision to pursue claims
to certain embodiments in the ’479 patent, while limiting the ’841 patent to the blocking
method. When prosecuting the ’841 patent, the patentees stated:
The present invention is directed to chromosome-specific staining by in
situ hybridization. One aspect of the invention involves disabling the
hybridization capacity of repeat sequences. In one embodiment, that
disabling is performed by selective blocking of the repetitive sequences.
All of the newly added claims are directed to this embodiment of the
invention.
Previously, the broadest claims had been directed to the generic invention
where the repetitive sequences are disabled by any means, the other
major embodiment being by removal of the repetitive sequences. Claims
to that subject matter, which applicants also believe to be patentable, will
be pursued in a separate application.
Supp. J.A. 6124 (emphases added). That separate application became the ’479 patent.
Notably, the patentees’ statements in the prosecution history of the ’841 patent indicate
two important points, viz., that the disabling of the hybridization capacity of repetitive
sequences by blocking was a key aspect of the ’841 invention and that claims to
embodiments involving the removal of repetitive sequences would be pursued in a
separate application. Hence, the addition of “unique sequence” to the heterogeneous
mixture limitation, coupled with the patentees’ statements during prosecution, evince a
clear intent to limit the claims of the ’479 patent to those embodiments in which the
2006-1334, -1452, 2007-1202 14
repetitive sequences have been excluded from the heterogeneous mixture in order to
disable the hybridization capacity of repetitive sequences.
Appellants argue that the addition of the “unique sequence” limitation was not
made to overcome the enablement rejection—but instead was added to overcome the
anticipation rejection. In particular, appellants contend that the patentees added the
“unique sequence” language to the ’479 patent to distinguish the invention from the
§ 102(b) prior art references. According to appellants, the prior art references used
repetitive sequence probes for the detection of repetitive sequences, in contrast to the
’479 invention which used unique sequence probes for the detection of unique
sequences. As such, because the addition of “unique sequence” had nothing to do with
the issue concerning the nonspecific binding of repetitive sequences—an issue raised
by the examiner in connection with the enablement rejection—appellants argue that the
patentees did not intend to limit the scope of the heterogeneous mixture by adding
“unique sequence” to the claims.
We are not persuaded by appellants’ argument. As a preliminary matter, only
two of the three prior art references disclose the use of repetitive sequence probes to
detect repetitive sequences. Indeed, appellants acknowledge in their opening brief in
support of their summary judgment appeal that the third reference, Cannizzaro et al.,
“disclosed the use of unique sequence probes.” Thus, the argument that the patentees
inserted the “unique sequence” limitation to overcome the anticipation rejection in view
of the § 102(b) prior art references is unpersuasive.
2006-1334, -1452, 2007-1202 15
Second, the patentees’ statements in the Remarks section accompanying the
amendment indicate that other language in the amended claim was intended to
overcome the anticipation rejection. In particular, the patentees argued:
Claim 17 has been rejected under 35 U.S.C. § 102(b) as being anticipated
by any one of Landegent et al, Montgomery et al, or Cannizzaro et al. In
view of the cancellation of claim 17 in favor of new claims now of record, it
is believed that this rejection in view of the prior art is now moot. The prior
art fails to disclose or even suggest the methods of staining target
interface [sic] chromosomal DNA to detect amplifications, deletions and
rearrangements, as now claimed. Withdrawal of this rejection is thus
believed to be in order.
Supp. J.A. 6654 (emphasis added). Thus, based on the plain language of patentees’
statements, the patentees overcame the anticipation rejection by clarifying that the
claimed method of staining was applied to interphase chromosomal DNA, in contrast to
metaphase chromosomal DNA, which was disclosed in the prior art references. Indeed,
all three references state that probes for detecting target sequences were used on
metaphase chromosomes. See Supp. J.A. at 6618 (Landegent reference stating the
procedure was tested and optimized on “mouse satellite sequences in metaphase
preparations of a mouse-human hybrid cell line”); id. at 6630 (Montgomery reference
stating that “[h]ybridization with metaphase chromosomes in situ has localized these
sequences to either the homogeneously staining regions or double-minute
chromosomes”); id. at 9646 (Cannizzaro stating that “metaphase [chromosomes were]
examined from both subjects”) (emphases added). Thus, appellants’ contention that the
addition of “unique sequence” was added to overcome the anticipation rejection, rather
than the enablement rejection, is belied by the patentees’ own statements that the
2006-1334, -1452, 2007-1202 16
interphase limitation distinguished the invention over the prior art. 3 The “unique
sequence” addition was made at least in part to overcome the enablement rejection.
Appellants also argue that the district court’s construction is incorrect in light of
certain dependent claims that require inclusion of repetitive sequences. Appellants rely
on AK Steel Corp. v. Sollac and Ugine, 344 F.3d 1234, 1242 (Fed. Cir. 2003), for the
proposition that “dependent claims are presumed to be of narrower scope than the
independent claims from which they depend” under the doctrine of claim differentiation.
That argument, however, is likewise unpersuasive. Presumptions are rebuttable. We
have held that “[w]hile it is true that dependent claims can aid in interpreting the scope
of claims from which they depend, they are only an aid to interpretation and are not
conclusive.” N. Am. Vaccine, Inc. v. Am. Cyanamid Co., 7 F.3d 1571, 1577 (Fed. Cir.
1993). Indeed, the presumption created by the doctrine of claim differentiation is “not a
hard and fast rule and will be overcome by a contrary construction dictated by the
written description or prosecution history.” Seachange Int’l, Inc. v. C-COR, Inc., 413
F.3d 1361, 1369 (Fed. Cir. 2005). Here, as discussed above, the prosecution history
overcomes the presumption; the correct construction of “heterogeneous mixture” is one
that excludes repetitive sequences, notwithstanding the presence of certain dependent
claims that do not exclude them.
3
We note that in their brief, appellants argue that “the addition of the interphase
limitation was not sufficient to overcome the anticipation rejection” with regard to the
Landegent reference because that reference “discloses the use of labeled probes to
detect repetitive sequences in interphase cells.” Appellants’ Summ. J. Reply Br. at 12
(emphasis added). Our review of that reference, however, reveals that metaphase
chromosomes were used in the Landegent experiments and no mention of interphase
chromosomes was made. We thus find appellants’ statement to be unsubstantiated
and hence unpersuasive.
2006-1334, -1452, 2007-1202 17
We have considered appellants’ additional arguments in support of their position
that the heterogeneous mixture does not exclude repetitive sequences, and find no
basis for reversing the court’s claim construction. Accordingly, having determined that
the patentees limited the scope of the heterogeneous mixture to one that only contains
unique sequences, the court’s claim construction of “heterogeneous mixture containing
labeled unique sequence nucleic acid fragments” is affirmed. Thus, the court’s grant of
summary judgment of noninfringement as to the ’479 patent is affirmed.
2. Prosecution History Estoppel
The district court also granted summary judgment of noninfringement of the ’841
patent as to two accused products, viz., the HER2 kit and the TOP2A kit. In reaching
that conclusion, the court addressed the claim limitation “blocking nucleic acid”—a term
required by all the claims of the ’841 patent. In the district court, the parties stipulated
that “blocking nucleic acid” means “fragments of repetitive-sequence-enriched DNA or
RNA.” Because the HER2 and TOP2A kits do not use human DNA, and instead use
synthetic nucleic acids referred to as peptide nucleic acids (“PNA”), the court concluded
that those products do not literally infringe the ’841 patent. The court then considered
whether those products infringe under the doctrine of equivalents. After determining
that the patentees narrowed the scope of the “blocking nucleic acid” limitation during
prosecution, the court concluded that appellants were barred from asserting that PNAs
were an equivalent of a “blocking nucleic acid,” and granted summary judgment of
noninfringement under the doctrine of equivalents.
Appellants argue that the doctrine of prosecution history estoppel does not apply
here because the “nucleic acid” limitation was never narrowed during prosecution. In
2006-1334, -1452, 2007-1202 18
the alternative, even if prosecution history estoppel were applicable, appellants argue
that the presumption of surrender was overcome because the amendment was merely
tangential to the accused equivalent. In response, Dako argues that the court correctly
applied the presumption that the patentees surrendered equivalents of the nucleic acid
limitation and that appellants have failed to rebut that presumption.
We agree with appellants that the district court erred by applying prosecution
history estoppel to the “blocking nucleic acid” limitation. “Prosecution history estoppel
prevents a patentee from recapturing under the doctrine of equivalents subject matter
surrendered during prosecution to obtain a patent.” Cross Med. Prods., Inc. v.
Medtronic Sofamor Danek, Inc., 480 F.3d 1335, 1341 (Fed. Cir. 2007) (citing Festo
Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 741 (2002)). Thus, “a
narrowing amendment made to satisfy any requirement of the Patent Act may give rise
to an estoppel.” Festo, 535 U.S. at 736. “A patentee’s decision to narrow his claims
through amendment may be presumed to be a general disclaimer of the territory
between the original claim and the amended claim.” Id. at 740. The presumption of
surrender, however, “may be rebutted if the patentee can demonstrate that: (1) the
alleged equivalent would have been unforeseeable at the time . . . the narrowing
amendment was made; (2) the rationale underlying the narrowing amendment bore no
more than a tangential relation to the equivalent at issue; or (3) there was some other
reason suggesting that the patentee could not reasonably have been expected to have
described the alleged equivalent.” Honeywell Int’l Inc. v. Hamilton Sundstrand Corp.,
370 F.3d 1131, 1140 (Fed. Cir. 2004) (quotations omitted).
2006-1334, -1452, 2007-1202 19
In the present case, the prosecution history reveals that claim 1 of the ’841
patent was amended for a substantial reason related to patentability. In the ’841 patent
application, the patentees filed claims that were directed to general methods of
disabling the hybridization capacity of repetitive sequences, and also submitted a claim
that specifically recited blocking nucleic acids. In particular, the patentees’ application
claims 28 and 99 read as follows:
28. (Twice amended) A method of staining chromosomal DNA that can
be used to stain a particular chromosome type or portion thereof, or a
particular group of chromosome types or portions thereof, whether the
targeted chromosomal sequences are present at normal copy numbers for
diploid or haploid cells or at higher copy numbers, the method comprising
the steps of:
providing a heterogeneous mixture that contains labeled nucleic acid
fragments that are substantially complementary to unique sequence
regions of complexity of at least 35 kilobases (kb) in the targeted
chromosomal DNA[;]
disabling the hybridization capacity of repetitive sequences within said
heterogeneous mixture;
reacting the heterogeneous mixture with the target chromosomal DNA by
in situ hybridization; and
rendering visible the hybridized, labeled fragments.
99. The method of staining chromosomal DNA according to Claim 28
wherein said disabling step includes substantially blocking the labeled
repetitive nucleic acid fragments in the heterogeneous mixture by
hybridization with unlabeled repetitive nucleic acid fragments that are
complementary to those in the heterogeneous mixture.
J.A. 221, 238 (emphases added). The examiner issued several rejections of those
claims for, inter alia, indefiniteness, anticipation, and obviousness. Thereafter, on
February 5, 1993, the examiner conducted a personal interview with one of the
inventors and his counsel. The Examiner Interview Summary Record indicates that
2006-1334, -1452, 2007-1202 20
they discussed ways to distinguish the instant invention from certain prior art references
and further discussed a “proposed claim directed solely to the use of blocking nucleic
acids to direct probe hybridization to unique segments.” That claim, claim 132, read:
132. A method of staining chromosomal DNA comprising:
(a) providing 1) labeled nucleic acid that comprises fragments which are
substantially complementary to nucleic acid sequences within the
chromosomal DNA for which staining is desired, and 2) blocking nucleic
acid that comprises fragments which are substantially complementary to
repetitive sequences in the labeled nucleic acid;
(b) employing said labeled nucleic acid, blocking nucleic acid, and
chromosomal DNA in in situ hybridization so that labeled repetitive
sequences are substantially blocked from binding to the chromosomal
DNA, while allowing substantial hybridization of unique sequences within
the labeled nucleic acid to the chromosomal DNA.
Id. at 348 (emphases added). In filing that amendment, the patentees stated that the
claims of the ’841 patent would be limited to the embodiment involving the blocking
method and that claims to other embodiments, including the embodiment involving the
removal of repetitive sequences, would “be pursued in a separate application,” leading
to the ’479 patent. Because the prosecution history suggests that the patentees limited
the claim to the blocking method at least in part to overcome the examiner’s rejections,
the patentees presumptively surrendered all equivalents of the “blocking nucleic acid”
limitation.
However, even if the Festo presumption applies, we must consider whether
appellants rebutted the “presumption of total surrender by demonstrating that it did not
surrender the particular equivalent in question.” Festo Corp. v. Shoketsu Kinzoku
Kogyo Kabushiki Co., Ltd., 344 F.3d 1359, 1367 (Fed. Cir. 2003). Appellants rely on
the tangential ground in support of their assertion that the presumption has been
2006-1334, -1452, 2007-1202 21
rebutted. “[T]he inquiry into whether a patentee can rebut the Festo presumption under
the ‘tangential’ criterion focuses on the patentee’s objectively apparent reason for the
narrowing amendment.” Id. at 1369. Indeed, prosecution history estoppel will not bar
the doctrine of equivalents when “the reason for the narrowing amendment was
peripheral, or not directly relevant, to the alleged equivalent.” Id.
Here, the patentees identified two main reasons for the narrowing amendment.
First, the patentees narrowed the claims in order to “facilitate prosecution.” In deciding
to limit the claims of the ’841 patent to the blocking method and to pursue other means
of disabling in a separate application, the patentees argued that “[b]y separating the
different inventions into separate applications, it is believed that prosecution will be
facilitated.” Such a reason for amending the claim is clearly nonsubstantive and does
not help us in our analysis.
Second, and more significantly, however, the patentees did amend the claim in
order to distinguish the invention over the prior art. The examiner issued prior art
rejections in view of, inter alia, Weissman et al., Sealey et al., and Yunis et al. To
overcome those references, the patentees argued that the invention was new and
nonobvious because it used the blocking method in connection with in situ hybridization
for the detection of unique sequences. In contrast, the Weissman reference involved
the use of pure unique sequence probes—or probes from which repetitive sequences
have been removed—as opposed to blocking. Both the Sealey and Yunis references,
however, disclosed the use of the blocking method, but that method was limited to
testing the hybridization of repetitive sequences and did not concern targeting unique
sequences, as does the claimed use of blocking nucleic acids. As such, the patentees
2006-1334, -1452, 2007-1202 22
argued that the invention would not have been obvious in view of the prior art because a
person of ordinary skill would not have considered the use of blocking for the detection
of unique sequences.
The prosecution history therefore reveals that in narrowing the claim to overcome
the prior art rejections, the focus of the patentees’ arguments centered on the method of
blocking—not on the particular type of nucleic acid that could be used for blocking.
Indeed, the “nucleic acid” limitation was never narrowed during prosecution and was not
at issue in the office action rejecting the claims, the Examiner Interview Summary
Record, or the patentees’ remarks accompanying the amendment. Moreover, Dako
does not dispute that none of the cited references concerned the type of nucleic acid
that could perform the blocking, or mentioned the accused equivalent. We thus
conclude that appellants have met their burden of showing that the amendment did not
surrender the equivalent in question because the narrowing amendment was only
tangential to the accused PNA equivalent, i.e., the peptide nucleic acid. Accordingly,
the court erred in concluding that appellants are precluded by estoppel from asserting
that Dako’s products infringe under the doctrine of equivalents. Whether they do
infringe is a question of fact for the trial court to consider on remand.
C. Remaining Issue in the Preliminary Injunction Appeal
Appellants presented two issues in their preliminary injunction appeal—both
involving claim construction. The first issue related to the construction of the
“heterogeneous mixture” limitation, which we have already dealt with. The district court
denied appellant’s motion for a preliminary injunction upon concluding, inter alia, that
appellants failed to show a likelihood of success that the sole product at issue, viz.,
2006-1334, -1452, 2007-1202 23
Dako’s HER2 kit, met the “heterogeneous mixture” limitation of the ’479 patent. In light
of our affirmance of the court’s construction, we affirm the court’s denial of the
preliminary injunction.
Appellants also appeal the construction of another claim term that the court
construed in its preliminary injunction order, viz., “morphologically identifiable cell
nucleus.” While we need not reach that issue in light of our affirmance of the denial of
the preliminary injunction on the heterogeneous mixture ground, we will do so in the
interest of judicial efficiency, as the issue has been fully briefed and that term will likely
be at issue on remand.
The disputed claim term “morphologically identifiable cell nucleus” appears in
both the ’841 and ’479 patents. The district court construed that term as “a single cell
nucleus that contains the full complement of chromosomal DNA.” Appellants argue that
that construction is incorrect based on the specification and prosecution history of the
patents. According to appellants, the claim merely requires that the nucleus be
“capable of being identified by its form or function” and does not require the full set of
DNA.
In response, Dako argues that the intrinsic evidence supports the court’s
construction. Dako asserts that the patentees characterized the invention as one that
allows the detection of chromosomal abnormalities on a cell-by-cell basis and thus a full
set of chromosomal DNA is required to achieve that objective.
We agree with appellants that the district court erred in its construction of this
term. First, the plain language of the claim term “morphologically identifiable cell
nucleus” suggests that the nucleus must be identifiable by form or structure, and does
2006-1334, -1452, 2007-1202 24
not indicate that a full set of chromosomal DNA must be present in the cell nucleus.
Appellants note, and Dako does not dispute, that the word “morphological” generally
refers to form or structure, not to identity of chromosomal DNA content.
In addition, the prosecution history of the ’841 patent reveals that the term
“morphologically identifiable cell nucleus” was added to the claim to clarify that the
target chromosomal DNA remained in a natural biological structure during in situ
hybridization. Indeed, the patentees argued that:
The [addition of the “morphologically identifiable” language] addresses the
Examiner’s concern that the chromosomal DNA could have been taken
from a chromosome but processed prior to hybridization. It makes clear
that the in situ hybridization is conducted while the DNA is still present in a
morphologically recognizable chromosome or cell nucleus.
J.A. at 447. Thus, by adding the disputed phrase, the patentees clarified that “the in situ
hybridization is conducted while the DNA is still present in a morphologically identifiable
chromosome or cell nucleus.” The implication of that statement is that while the DNA is
still present, the identification is morphological, not by DNA identity. The patentees
contrasted that method with other methods, such as “Southern blot hybridization in
which the biological structure has been destroyed, and the DNA has been cut into
restriction fragments and separated by size.” Significantly, nowhere in the prosecution
history, or the specification for that matter, do we find any indication that the
“morphologically identifiable” language was added to impose a requirement that the cell
nucleus must retain its full complement of chromosomal DNA. Accordingly, the proper
construction of “morphologically identifiable cell nucleus” is one that is capable of being
identified by its form or structure—a construction that we find to be consistent with the
intrinsic evidence.
2006-1334, -1452, 2007-1202 25
CONCLUSION
For the foregoing reasons, we affirm the district court’s denial of the preliminary
injunction, affirm in part the court’s grant of summary judgment of noninfringement as to
the ’479 patent, and reverse in part the court’s grant of summary judgment of
noninfringement as to the ’841 patent with respect to the HER2 and TOP2A products.
We affirm the court’s construction of “heterogeneous mixture of labeled unique
sequence nucleic acid fragments,” reverse the court’s conclusion that appellants are
estopped from asserting that Dako’s products meet the “blocking nucleic acid” limitation
under the doctrine of equivalents, and reverse the court’s construction of
“morphologically identifiable cell nucleus.” The case is remanded to the district court for
further proceedings consistent with this opinion.
AFFIRMED IN PART, REVERSED IN PART, and REMANDED
COSTS
No costs.
2006-1334, -1452, 2007-1202 26
United States Court of Appeals for the Federal Circuit
2006-1334, -1452
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA,
ABBOTT MOLECULAR, INC., and ABBOTT LABORATORIES, INC.,
Plaintiffs-Appellants,
v.
DAKOCYTOMATION CALIFORNIA, INC.,
Defendant-Appellee.
------------------------------------------------------------------------------
2007-1202
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA,
ABBOTT MOLECULAR, INC., and ABBOTT LABORATORIES, INC.,
Plaintiffs-Appellants,
v.
DAKO A/S,
and DAKO NORTH AMERICAN, INC.,
Defendants-Appellees.
Appeal from the United States District Court for the Northern District of California
in case no. 05-CV-03955, Judge Marilyn Hall Patel.
PROST, Circuit Judge, dissenting-in-part.
I join the majority opinion except for Part B.2 of the Discussion section, reversing
the district court and holding that the doctrine of equivalents is not precluded by
prosecution history estoppel because the tangential exception applies, from which I
respectfully dissent. The majority concludes that, by amending the claims, the
patentees surrendered all other methods of disabling the hybridization capacity of
repetitive sequences, but did not surrender equivalents of the nucleic acid that could be
used to perform the blocking. In my view, this conclusion is contrary to this court’s
precedent and to the proper application of prosecution history estoppel as set forth by
the Supreme Court.
Under Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. (“Festo I”), if the
patentee narrows the scope of the claims of the patent in response to a rejection during
prosecution, there is a presumption that the patentee is estopped from arguing that the
surrendered territory comprises an equivalent for the purposes of infringement under
the doctrine of equivalents. 535 U.S. 722, 739-40 (2002); see Int’l Rectifier Corp. v.
IXYS Corp., Nos. 2007-1063, -1141, -1165, slip op. at 7 (Fed. Cir. Feb. 11, 2008).
Prosecution history estoppel applies to any narrowing amendment made for a
substantial reason related to patentability. Festo I, 535 U.S. at 739-40. The majority
recognizes that the amendment here was made in order to overcome certain prior art
references and, thus, the amendment was made for a substantial reason related to
patentability. A narrowing amendment is all that is required for the presumption of
prosecution history estoppel to attach to bar the application of the doctrine of
equivalents.
The presumption of prosecution history estoppel with regard to a narrowing
amendment is absolute, i.e., an amendment is “presumed to be a general disclaimer of
the territory between the original claim and the amended claim.” Festo I, 535 U.S. at
740; Biagro W. Sales, Inc. v. Grow More, Inc., 423 F.3d 1296,1305 (Fed. Cir. 2005);
Terlep v. Brinkmann Corp., 418 F.3d 1379, 1385 (Fed. Cir. 2005). The fact that
2006-1334, -1452, 2007-1202 2
narrowing the claim to a method of blocking with a “blocking nucleic acid” may not have
been necessary to distinguish over the prior art does not change the analysis. As this
court has previously stated:
[T]here is no principle of patent law that the scope of a surrender of
subject matter during prosecution is limited to what is absolutely
necessary to avoid a prior art reference that was the basis for an
examiner’s rejection. To the contrary, it frequently happens that patentees
surrender more through amendment than may have been absolutely
necessary to avoid particular prior art. In such cases, we have held the
patentees to the scope of what they ultimately claim, and we have not
allowed them to assert that claims should be interpreted as if they had
surrendered only what they had to.
Norian Corp. v. Styker Corp., 432 F.3d 1356, 1361-62 (Fed. Cir. 2005). Here, the
amendment narrowed the scope of the invention from any method of disabling the
hybridization capacity of repetitive sequences to a method of disabling repetitive
sequences using “blocking nucleic acids.” The parties have stipulated that “blocking
nucleic acid” means “fragments of repetitive-sequence-enriched DNA or RNA.”
Therefore, the patentee surrendered all other methods for disabling hybridization
capacity of repetitive sequences including methods of blocking other than with DNA or
RNA. It is irrelevant to the determination of the scope of the surrendered territory that to
overcome the prior art references the patentee did not need to amend the claims to a
method of disabling the hybridization capacity of repetitive sequences by blocking with a
“blocking nucleic acid,” but instead could have amended the claims to a method of
disabling repetitive sequences by blocking.
Under Festo I, the presumption of a wholesale surrender of territory between the
original claim and the amended claim may only be rebutted if the patentee is able to
show that one of the exceptions applies. 535 U.S. at 740-41. The appellants do not
2006-1334, -1452, 2007-1202 3
suggest that this case falls under the “some other reason” exception. The appellants do
not and cannot assert the “unforeseeable” exception since PNAs were discovered prior
to when the narrowing amendment was made. See Festo Corp. v. Shoketsu Kinzoku
Kogyo Kabushiki Co. (“Festo II”), 344 F.3d 1359, 1369 (Fed. Cir. 2003). Rather, before
the district court and on appeal, the appellants raised only the tangential exception. The
majority agrees that the tangential exception bars application of prosecution history
estoppel. In so concluding, they reason that the patentee, in narrowing the claims to
overcome the prior art, focused on the method of blocking and not on the particular type
of nucleic acid that could be used in the blocking.
“[T]he inquiry into whether a patentee can rebut the Festo presumption under the
‘tangential’ criterion focuses on the patentee’s objectively apparent reason for the
narrowing amendment.” Id. The primary consideration is “whether the amendment is
peripheral or not directly relevant, to the alleged equivalent.” Id. Here, the reason for
the amendment bears more than a tangential relationship to the equivalent. The
amendment limits the claims to a method of disabling repetitive sequences by blocking
with “blocking nucleic acids” (i.e., DNA or RNA). In making the amendment, the
appellants presumptively surrendered any other means of disabling repetitive
sequences. The equivalent, PNA, however, functions to do exactly that, i.e., to disable
repetitive sequences. Hence, the purpose for the amendment is not unrelated to the
equivalent. See Int’l Rectifier, slip op. at 9-10; Cross Med. Prods., Inc. v. Medtronic
Sofamor Danek, Inc., 480 F.3d 1335, 1343 (Fed. Cir. 2007); Biagro, 423 F.3d at 1306;
Terlep, 418 F.3d at 1379; Rhodia Chimie v. PPG Indus. Inc., 402 F.3d 1371, 1383 (Fed.
Cir. 2005).
2006-1334, -1452, 2007-1202 4
The appellants rely on two cases to support application of the tangential
exception, Insituform Technologies, Inc. v. CAT Contracting, Inc., 385 F.3d 1360 (Fed.
Cir. 2004), and Primos, Inc. v. Hunter’s Specialties, Inc., 451 F.3d 841 (Fed. Cir. 2006).
However, this case is distinguishable from both of those cases. The patent at issue in
Insituform was directed to a method for performing pipe repair without removing the
damaged pipe from the ground. 385 F.3d at 1362. The patented method comprised
impregnating a curable resin to the inside of the tube while applying a vacuum. Id. at
1368-69. The original claims did not specify the position or number of vacuum cups. Id.
at 1369. The prior art method suffered from the problem that the vacuum was at the far
end of the tube opposite the resin source and required an exceedingly large suction
compressor. Id. To overcome the prior art, the patent claims were amended to specify
that the vacuum source was close to the resin source. Id. at 1369-70. The alleged
equivalent differed from the claimed method only in that it used multiple vacuum cups.
Id. at 1369. Thus, we held that the narrowing amendment was tangential to the
equivalent, which used multiple cups. Id. at 1370.
In Primos, the patent was directed to a diaphragm mouth call used by hunters to
simulate animal sounds. 451 F.3d at 843. The prior art device contained a shelf
structure which was directly above the membrane with no space in between. Id. at 849.
During prosecution, the claims were amended to add a limitation requiring that the plate
be “differentially spaced” above the membrane. Id. The alleged equivalent contained a
dome, instead of a plate, which was similarly spaced above the membrane. Id. We
concluded, therefore, that the equivalent (dome as opposed to plate) was tangential to
2006-1334, -1452, 2007-1202 5
the purpose of the amendment, which was to require spacing between the plate and the
membrane. Id.
In both Insituform and Primos, “the reason for the amendment and the alleged
equivalent involved different aspects of the invention.” Biagro, 423 F.3d at 1306. Here,
the purpose for the amendment and the accused equivalent do not involve different
aspects of the invention. Indeed, they both relate to the means for disabling repetitive
sequences. Therefore, the equivalent is not tangential to the purpose for the
amendment. To overcome the presumption of prosecution history estoppel “[t]he
patentee must show that at the time of the amendment one skilled in the art could not
reasonably be expected to have drafted a claim that would have literally encompassed
the alleged equivalent.” Festo I, 535 U.S. at 741. Here, the appellants could
reasonably have been expected to have drafted a claim that encompassed blocking
repetitive sequences using PNA. The appellants should, therefore, be estopped from
asserting that PNA is an equivalent to “blocking nucleic acid” in the ’841 patent.
For these reasons, I respectfully dissent.
2006-1334, -1452, 2007-1202 6