Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-cand-3_05-cv-03955/USCOURTS-cand-3_05-cv-03955-17/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 35:271 Patent Infringement

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UNITED STATES DISTRICT COURT

NORTHERN DISTRICT OF CALIFORNIA

THE REGENTS OF THE UNIVERSITY OF

CALIFORNIA, ABBOTT MOLECULAR INC., and

ABBOTT LABORATORIES INC.,

Plaintiffs,

v.

DAKO NORTH AMERICA, INC. and DAKO A/S,

Defendants.

 /

No. C 05-03955 MHP

MEMORANDUM & ORDER

Re: Motion for Summary Judgment

Plaintiffs The Regents of the University of California (“UC Regents”), Abbott Molecular

Inc., and Abbott Laboratories Inc. (collectively, “Abbott”) brought this patent infringement action

against defendants Dako North America, Inc. and Dako A/S (collectively, “Dako”), alleging

infringement of two United States patents related to in situ DNA hybridization. Now before the

court is Dako’s motion for summary judgment of noninfringement. Having considered the parties’

arguments and submissions, and for the reasons set forth below, the court enters the following

memorandum and order.

BACKGROUND

The history of this litigation and the nature of the technology at issue are already discussed in

some detail in the court’s previous orders and need not be repeated in full here. The following

summary is sufficient for purposes of resolving Dako’s motion.

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Abbott holds the two patents at issue in this lawsuit, U.S. Patent No. 5,447,841 (the “‘841

patent”) and U.S. Patent No. 6,596,479 (the “‘479 patent”). The two asserted patents have

substantially identical specifications but were issued almost eight years apart and have different

claims. Both patents relate to the identification and analysis of target genes in a tissue sample

through DNA hybridization. In DNA hybridization, sections of nucleic acid that are labeled, usually

with a fluorescent dye (“hybridization probes”), are bonded to complementary “target” regions of

chromosomal DNA—typically, sections which encode a protein of interest. See, e.g., ‘841 patent at

cols. 2–3. The fluorescent label provides visual confirmation of the presence of the target gene. Id.

Dako manufactures diagnostic kits which make use of DNA hybridization to determine the

presence and frequency of certain genes of interest, as well as information about whether genes of

interest have undergone translocation. The accused products differ in some respects, but share two

relevant characteristics. First, the parties do not dispute that each accused product employs a

mixture of labeled probes which includes both unique sequence and repetitive sequence fragments,

as construed by this court. Second, the parties agree that each accused product uses a synthetic

compound called “PNA” to block the binding of repeat sequence fragments to the target

chromosomal DNA.

Abbott filed this lawsuit on September 29, 2005 and moved for a preliminary injunction on

October 17. In connection with the motion for a preliminary injunction, the parties proposed

definitions for certain critical terms in the patent. The court construed the phrase “morphologically

identifiable cell nucleus” (in the ‘479 patent) and “morphologically identifiable . . . cell nucleus” (in

the ‘841 patent) to mean “a single cell nucleus that contains the full complement of chromosomal

DNA.” The court also considered the meaning of the phrase “heterogeneous mixture of labeled

unique sequence nucleic acid fragments,” found in claim 1 of the’479 patent. On the incomplete

record available at the time of resolving the motion for a preliminary injunction, the court concluded

that the recited “heterogeneous mixture” could not include repeat sequence fragments. In light of

the court’s preliminary claim construction, questions regarding the validity and enforceability of the

asserted patents, and the apparent adequacy of monetary damages, the court denied Abbott’s motion

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for a preliminary injunction. Abbott’s interlocutory appeal of the denial, including the proposed

constructions of “morphologically identifiable cell nucleus” and “heterogeneous mixture of labeled

unique sequence nucleic acid fragments,” is currently pending before the Federal Circuit.

The parties subsequently submitted proposed constructions for the remaining disputed claim

terms, which this court construed in a recently issued order. Relevant to the instant motion, the court

revised its construction of the phrase “heterogeneous mixture of labeled unique sequence nucleic

acid fragments” to mean “a heterogeneous mixture of labeled nucleic acid fragments that includes

unique sequence fragments.” The parties have also stipulated that the phrase “nucleic acid” does not

literally encompass the synthetic PNA which the accused products employ to block the binding of

repeat labeled fragments.

Simultaneously with the claim construction briefing, Dako filed the instant motion for

summary judgment. Dako based its motion on the court’s preliminary constructions of

“morphologically identifiable cell nucleus” and “heterogeneous mixture of labeled unique sequence

nucleic acid fragments,” as well as the stipulation that “nucleic acid” does not literally encompass

PNA. Abbott opposes the motion on the merits, and further moves for postponement of the motion

and additional discovery under Federal Rule of Civil Procedure 56(f).

LEGAL STANDARD

I. Summary Judgment

Summary judgment is proper when the pleadings, discovery and affidavits show that there is

“no genuine issue as to any material fact and that the moving party is entitled to judgment as a

matter of law.” Fed. R. Civ. P. 56(c). Material facts are those which may affect the outcome of the

case. Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248 (1986). A dispute as to a material fact is

genuine if there is sufficient evidence for a reasonable jury to return a verdict for the nonmoving

party. Id. The party moving for summary judgment bears the burden of identifying those portions

of the pleadings, discovery, and affidavits that demonstrate the absence of a genuine issue of

material fact. Celotex Corp. v. Cattrett, 477 U.S. 317, 323 (1986). On an issue for which the

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opposing party will have the burden of proof at trial, the moving party need only point out “that

there is an absence of evidence to support the nonmoving party’s case.” Id.

Once the moving party meets its initial burden, the nonmoving party must go beyond the

pleadings and, by its own affidavits or discovery, “set forth specific facts showing that there is a

genuine issue for trial.” Fed. R. Civ. P. 56(e). Mere allegations or denials do not defeat a moving

party’s allegations. Id.; Gasaway v. Northwestern Mut. Life Ins. Co., 26 F.3d 957, 960 (9th Cir.

1994). The court may not make credibility determinations, and inferences to be drawn from the

facts must be viewed in the light most favorable to the party opposing the motion. Masson v. New

Yorker Magazine, 501 U.S. 496, 520 (1991); Anderson, 477 U.S. at 249.

The moving party may “move with or without supporting affidavits for a summary judgment

in the party’s favor upon all or any part thereof.” Fed. R. Civ. P. 56(a). “Supporting and opposing

affidavits shall be made on personal knowledge, shall set forth such facts as would be admissible in

evidence, and shall show affirmatively that the affiant is competent to testify to the matters stated

therein.” Fed. R. Civ. P. 56(e).

II. Patent Infringement

Determination of infringement is a two-step process. First, the court must determine the

meaning of the language of the claims, a question of law. Markman v. Westview Instruments, Inc.,

517 U.S. 370, 384 (1996). Second, the finder of fact must compare the construed claims to the

accused product, to determine if each claim element is present, either literally or under the doctrine

of equivalents. Irdeto Access, Inc. v. Echostart Satellite Corp., 383 F.3d 1295, 1299 (Fed. Cir.

2004).

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DISCUSSION

I. ‘479 Patent

A. Construction of “heterogeneous mixture of labeled unique sequence nucleic acid

fragments”

Dako filed its summary judgment motion based on the court’s observations in the

preliminary injunction as to the likely construction of “heterogeneous mixture of labeled unique

sequence nucleic acid fragments.” The court revised its interpretation of this phrase in light of the

more thorough claim construction briefing submitted by the parties, ultimately accepting Abbott’s

argument that the word “of,” read in the context of the dependent claims of the ‘479 patent, should

be construed to mean “comprising.” Although the court expressed concerns about adopting the

broad construction proposed by Abbott—particularly in light of the inoperative subject matter

encompassed in Abbott’s interpretation of the claim—the court found that the relationship among

the independent and dependent claims provided clear evidence that the patentee intended to allow

the heterogeneous mixture recited in claim 1 to include repetitive as well as unique fragments.

In the briefs accompanying the instant motion, however, Dako has discussed additional

excerpts from the prosecution history which call the court’s previous construction into question. 

The excerpts were included in the declarations accompanying the parties’ Markman submissions but

were not cited in the accompanying briefs or highlighted at argument.1

 The cited excerpts follow the

development of the claims of the ‘479 patent in some detail, and bear careful review.

Originally filed application claim 17, which is the predecessor to claim 1 of the ‘479 patent,

read as follows:

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.

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Hoffman Dec., Exh. N at 47. Of particular note is that claim 17 recited a “heterogeneous mixture of

labeled nucleic acid fragments,” without the “unique sequence” modifier. See id. The examiner

rejected the claim under 35 U.S.C. section 112 for lack of enablement, noting that

the disclosure is enabling only for claims limited to reacting practice (last 2 lines of

claim 17) which promotes at least some specificity of hybridization so as to stain only

the desired target chromosome or portion thereof. As worded there is no specificity

practice in the actual claim steps that would result in staining of the target only

without so much background that the desired target nucleic acid would be obscured.

Id., Exh. O at 2 (emphasis added). In other words, claim 17 as drafted contained no provision for

reducing nonspecific binding. This court noted precisely the same concern in its Markman order. 

Slip op. at 8–9.

In response to the rejection, the applicants cancelled the pending claims and submitted

amended claims. Amended application claim 18, which is also the predecessor to claim 1 in the

final patent, read as follows:

18. A method of staining target interphase chromosomal DNA to detect

amplifications, deletions, 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.

Hoffman Dec., Exh. P at 2. Although the claim language changed in several ways in the progression

from claim 17 to claim 18—such as adding the types of conditions to be detected, the requirement

that the process be performed on interphase DNA, and the “morphologically identifiable cell

nucleus” limitation—the only changes to address the examiner’s concern regarding nonspecific

binding were the addition of the phrase “unique sequence” and the clarification that the recited

fragments are “substantially complementary to nucleic acid segments within the interphase

chromosomal DNA for which detection is desired.”

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The applicants did not provide a detailed explanation of the significance of their changes, but

argued that the previous rejection under section 112 was moot in light of the newly drafted claims. 

The examiner accepted the applicants’ argument that the change adequately addressed the

enablement concern. Id., Exh. Q at 3–4. It is also apparent that the examiner recognized that the

fragments in the heterogeneous mixture were intended to bond only to the target region, as

demonstrated by the examiner’s question as to whether use of the word “unique” was appropriate to

cover “detecting apparently non-unique ‘extra’ chromosomes”—i.e., targets which occurred more

than once per haploid. Id., Exh. Q at 4.

The dependent claims added as part of the same amendment are also revealing, as they do not

include the later-added dependent claims which this court found to support Abbott’s proposed

construction. See id., Exh. P at 1–4. Dependent claim 12, which recites the inclusion of repetitive

sequence fragments in the heterogeneous mixture, was not added until March 1999, almost two-andone-half years after the applicants added the “unique sequence” limitation. Id., Exh. V at 2.

The cited excerpts are significant because they evince a disclaimer of methods employing

labeled repeat sequence fragments, the inclusion of which in the probe mixture would result in “so

much background that the desired target nucleic acid would be obscured.” Cf. id., Exh. O at 2. 

Based on the approaches to reducing nonspecific binding set forth in the specification, the applicant

could have chosen to address the examiner’s section 112 rejection in two ways: the addition of

blocking nucleic acid to prevent the repeat sequence fragments from hybridizing to the target, or the

elimination of repeat sequence probes from the heterogeneous mixture. By representing to the

examiner that the amended claim, which did not include any limitation requiring blocking, addressed

the problem of nonspecific binding, the applicants represented that the claimed heterogeneous

mixture would not bind to undesirable locations—in other words, that the claimed mixture was free

of repeat sequence fragments.

In addition, as the court observed in the claim construction order, the applicants argued to the

examiner that “‘[u]nique sequence nucleic acid fragments are in contrast with, and free of,

‘repetitive sequence’ nucleic acid.” Slip op. at 10. The court previously noted in its Markman order

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that this definition for “unique” is compatible with Abbott’s proposed construction, which depends

on the word “of” for inclusion of repetitive sequence fragments in addition to the unique sequence

fragments which are expressly recited in the claim. Id. Viewed in the broader context of the

purpose for adding the “unique sequence” modifier, however—overcoming the examiner’s rejection

for inoperability—the applicant’s definition of the word “unique” provides further evidence that the

applicant disclaimed embodiments using repeat sequence fragments and blocking as part of the

amendment.

A patent applicant may relinquish subject matter through claim cancellation or amendment

during prosecution. “The doctrine of prosecution disclaimer is well established in Supreme Court

precedent, precluding patentees from recapturing through claim interpretation specific meanings

disclaimed during prosecution.” Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1323 (Fed. Cir.

2003). Under the doctrine of prosecution disclaimer, which is distinct from prosecution history

estoppel, the literal scope of claim terms is limited as a result of disclaimers made during

prosecution: “a claim in a patent as allowed must be read and interpreted with reference to claims

that have been cancelled or rejected, and the claims allowed cannot by construction be read to cover

what was thus eliminated from the patent.” Id. (citing Schriber-Schroth Co. v. Cleveland Trust Co.,

311 U.S. 211, 220–21 (1940)).

Here, it is clear from the file history that the “unique sequence” limitation was added to

address the examiner’s concern about the lack of any claim element which would reduce nonspecific

binding. Abbott’s proposed construction in this case—that the heterogeneous mixture might include

repeat sequence fragments—is equivalent in scope to the broader claim limitation rejected by the

examiner. Abbott cannot reclaim what it relinquished.

Abbott argues that the words “unique sequence” were added only to clarify that the

heterogeneous mixture must contain some unique sequence fragments, in addition to whatever repeat

sequence fragments might be present. In support of this argument, Abbott notes that as part of the

same office action in which the examiner rejected claim 17 under section 112, the examiner also

rejected claim 17 under section 102(b) as anticipated by three pieces of prior art. Two of the

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references described the use of heterogeneous mixtures of labeled repeat sequence DNA; the third

reference described the use of labeled unique sequence DNA. Hoffman Dec., Exh. O at 3–4. Abbott

notes that none of the cited references used a mixture of unique and repeat sequence fragments and

argues that the modified version of claim 17 is distinct because it includes both.

Abbott’s alternate explanation is not plausible because the applicant did not distinguish the

amended claim 17 from the cited prior art on the basis of the “unique sequence” limitation. Instead,

the applicant distinguished the prior art by limiting the use of the claimed method to interphase DNA

and by requiring that the method detect amplifications, deletions and rearrangements: “The prior art

fails to disclose or even suggest the methods of staining target interface [sic: interphase]

chromosomal DNA to detect amplifications, deletions and rearrangements, as now claimed.” Id.,

Exh. P at 5. Also, as Dako correctly points out, the phrase “heterogeneous mixture” as defined

generally in the specification for the ‘479 patent clearly includes unique sequence fragments: “In

particular, chromosome specific staining reagents are provided which comprise heterogeneous

mixtures of labeled nucleic acid fragments having substantial portions of substantially

complementary base sequences to the chromosomal DNA for which specific staining is desired.” 

‘479 patent at 3:51–56. Thus it was not necessary to add the “unique sequence” modifier to suggest

that the heterogeneous mixture included some unique sequences.

Abbott also argues, as it did at the claim construction hearing, that the examiner must have

understood the claim to include repeat sequence fragments when she allowed dependent claims 12

through 14 to be added without objection. Abbott, however, does not cite any portion of the file

history suggesting that the examiner considered the tension between her previous rejection under

section 112 and her subsequent allowance of claim 12. Absent some explanation for or qualification

of the otherwise clear disclaimer, Abbott is not entitled to recover the disclaimed scope. The court

therefore modifies its construction of the phrase “heterogeneous mixture of labeled unique sequence

nucleic acid fragments” to mean “a heterogeneous mixture of labeled nucleic acid fragments that

includes only unique sequence fragments.”

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B. Literal Infringement of the ‘479 Patent

The parties do not dispute that each of Dako’s accused kits employs a mixture of nucleic acid

fragments which includes repeat sequence fragments. Thus there is no dispute, given the revised

claim construction, that Dako’s kits do not literally infringe the ‘479 patent.

C. Infringement of the ‘479 Patent Under the Doctrine of Equivalents

The prosecution history discussed supra is equally applicable in evaluating infringement

under the Doctrine of Equivalents. See Terlep v. Brinkmann Corp., 418 F.3d 1379, 1385–86 (Fed.

Cir. 2005) (relying on an amendment during prosecution both in determining the literal scope of a

claim and in assessing infringement under the Doctrine of Equivalents). Determining whether

prosecution history estoppel applies is a two-step process. First, if there was a narrowing

amendment made during prosecution, a presumption arises that the applicant “surrendered the

territory between the original claims and the amended claims.” Id. at 1385. The patentee may

overcome the presumption by showing that “the alleged equivalent was unforeseeable at the time the

amendment was made, that the alleged equivalent was tangential to the purpose of that amendment,

or that there was some other reason suggesting that the patentee could not reasonably be expected to

have described the insubstantial substitute in question.” Id. (citing Festo Corp. v. Shoketsu Kinzoku

Kogyo Kabushiki Co., 535 U.S. 722, 740–41 (2002)).

Here, the addition of “unique sequence” to the claims was clearly narrowing, as it limited the

claimed process to the use of unique sequence fragments in hybridization. Abbott does not attempt

to argue that the use of blocking agents was unforeseeable (as it is discussed at length in the

specification for the ‘479 patent) or that the abandoned equivalent was tangential to the purpose of

the amendment. The court therefore concludes that none of the accused products infringes the ‘479

patent under the Doctrine of Equivalents. Dako’s motion for summary judgment with respect to the

‘479 patent is therefore granted.

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II. ‘841 Patent

A. Construction of “blocking nucleic acid”

The parties have stipulated that the phrase “blocking nucleic acid” in claim 1 of the ‘841

patent means “fragments of repetitive-sequence-enriched DNA or RNA.” Hoffman Dec., Exh. Y at

2. The court will therefore consider whether the phrase as the parties have defined it covers the

accused products.

B. Literal Infringement of the ‘841 Patent

Abbott argues that most of the accused Dako kits, which indisputably employ PNA to block

the binding of repeat sequence labeled fragments, also make use of DNA to perform a blocking

function. With two exceptions, each accused product includes unlabeled “total human DNA” as

well as unlabeled PNA. Chang Dec., Exh. I at 180:25–182:20. Abbott argues that total human DNA

is rich in repeat sequences and serves a blocking function, therefore falling within the literal scope of

the “blocking nucleic acid” recited in claim 1 of the ‘841 patent. Dako argues that total human DNA

does not satisfy the claim limitation because it is not artificially “enriched” with additional repeat

sequence fragments.

The parties’ dispute has two separate components. First, although the parties purported to

stipulate to a definition for “blocking nucleic acid,” they apparently disagree as to the meaning of

the word “enriched” in the stipulated construction. Abbott interprets “enriched” as meaning that the

DNA must have a high ratio of repeat to unique sequences. Dako argues that “enriched” means that

the ratio of repeat to unique sequences must be above that found in naturally occurring DNA. 

Although neither party addressed the proper claim construction in their briefs, both offered various

citations to the intrinsic record at oral argument.

Assuming for the sake of argument that Dako’s proposed interpretation is correct, Abbott

also claims that the total human DNA used in Dako’s kits may have a higher proportion of repeat

sequences than naturally occurring DNA. At oral argument, Abbott claimed that total human DNA

is generally manufactured by subjecting a single set of DNA to amplification. During the

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amplification process repeat sequence fragments are duplicated at a higher rate than unique sequence

fragments. Thus the resulting DNA contains a higher proportion of repeat sequence fragments than

normal human DNA.

The court finds that the record submitted in connection with Dako’s motion is not developed

enough to permit construction of “blocking nucleic acid” or application of the properly construed

phrase to Dako’s kits. The parties were unable to address the issue in detail in their briefs because

Abbott did not disclose its literal infringement contention based on the total human DNA as part of

its preliminary infringement contentions. See Hoffman Dec., Exh. BB. The court also notes that

Abbott’s representations at oral argument about the effect of creating large quantities of total human

DNA through amplification appear to lack support in the current factual record. Abbott submitted a

supplemental declaration from Professor David Pinkel in support of its contention that total human

DNA can be an effective blocking agent, but the article attached to the declaration does not appear to

describe the process by which total human DNA is manufactured. The only relevant passage the

court has discovered describes the total human DNA as follows: “Placental DNA (Sigma) was

treated with proteinase K, extracted with phenol, and sonicated to a size range of 200–600 base pairs

(bp).” Supp. Pinkel Dec., Exh. A at 9139. This passage appears to describe the preparation of total

human DNA without the use of amplification.

Without a clear record, the court must deny Dako’s motion under Rule 56(f), subject to

renewal at the point when a fully developed record as to the proper construction of “blocking nucleic

acid” and the use of total human DNA in Dako’s accused kits becomes available.

Two of Dako’s products, however—the HER2 kit and the TOP2A kit—do not make use of

total human DNA at all and therefore do not literally infringe the claims of the ‘841 patent. The

court will therefore consider infringement under the Doctrine of Equivalents for those two products.

C. Infringement of the ‘841 Patent Under the Doctrine of Equivalents

The “blocking nucleic acid” limitation was not present in the original claims of the ‘841

patent, but was added during prosecution. The earliest claims of the ‘841 patent purported to cover

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“the generic invention where the repetitive sequences are disabled by any means.” Chang Dec.,

Exh. D at A-351. The claims ultimately pursued in connection with the ‘841 patent, however, were

limited by the applicant to methods in which “disabling is performed by selective blocking of the

repetitive sequences.” Id. The broader claims were pursued in connection with a divisional

application. Dako contends that the limitation of the claims to the use of blocking was a narrowing

amendment for a substantial reason related to patentability, giving rise to a presumption of

prosecution history estoppel.

Prior to the amendment in question, application claim 28 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.

Id. at A-221–22 (editorial notations omitted and emphasis added). Dependent application claim 99,

prior to the amendment in question, recited

[t]he 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.

Id. at A-238.

The examiner rejected application claim 28 as anticipated by or obvious in light of a prior art

reference (“Weissman”) which disclosed the use of “single-copy” probes in hybridization. Id. at A318–21. In Weissman, repeat sequence probes were eliminated from the probe mixture “by

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preassociation with total human DNA.” Id. at A-320. In response to the rejection, the applicants

cancelled their existing claims and added application claim 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 A-348.

Dako argues that claim 132 is a narrowing amendment because it incorporates the limitations

of formerly dependent claim 99 into the previous independent claim 28. Incorporating the

limitations of a dependent claim into an independent claim is a narrowing amendment when it is

done to avoid a rejection:

Thus, the fact that the scope of the rewritten claim has remained unchanged will not

preclude the application of prosecution history estoppel if, by canceling the original

independent claim and rewriting the dependent claims into independent form, the

scope of subject matter claimed in the independent claim has been narrowed to secure

the patent.

Honeywell Int’l Inc. v. Hamilton Sundstrand Corp., 370 F.3d 1131, 1142 (Fed. Cir. 2004) (en banc). 

Abbott argues that the amendment is not narrowing under Honeywell because although claim

132 requires the use of “blocking nucleic acid” to disable the hybridization capacity of the repetitive

sequence labeled probes, it is broader than claims 28 and 99 in other respects. For example, claim

132 omits any requirement as to the length of the unique sequence regions and does not require

“rendering visible the hybridized fragments.” The fact that the new claim may have broadened in

other, unrelated respects is not relevant to determining whether prosecution history estoppel applies

to the disputed element, as prosecution history estoppel is evaluated on an element-by-element basis.

Id. at 1144 (“The scope of the patentee’s concession is determined on a limitation-by-limitation

basis.”); see also Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359, 1367 (Fed.

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Cir. 2003) (en banc) (“Festo VIII imposes the presumption that the patentee has surrendered all

territory between the original claim limitation and the amended claim limitation.”). Here, limiting

the methods of “disabling the hybridization capacity of repetitive sequences” to the use of blocking

nucleic acid provided a basis for distinguishing Weissman, which used preassociation with total

human DNA to remove repeat sequence probes prior to hybridization. See Chang Dec., Exh. D at

A-351 (“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 . . . will be pursued in a separate application.”)

(emphasis added); id. at A-355–56 (distinguishing Weissman on the basis that “prior to the filing of

the grandparent to the present application in January 1986, the direction of the art for unique

sequence in situ hybridization involved careful selection of probes that did not contain repetitive

sequences” and that “until the grandparent to the present application was filed in January 1986, the

use of blocking copies of a sequence in in situ hybridization had been limited to testing whether a

hybridization signal was due to repeat sequences.”).

Abbott also argues that claim 132 should not be viewed as a narrowing amendment because

the applicant continued to pursue the broader claim in a divisional application. This argument is not

persuasive because the fact that Abbott pursued the disclaimed subject matter in prosecuting another

patent has no bearing on the proper range of equivalents for the claims of the ‘841 patent. As noted

supra, the applicant disavowed the subject pursued in the divisional application, in the context of the

‘841 patent, by adding the blocking limitation. Id., Exh. D at A-351 (“Claims to that subject matter .

. . will be pursued in a separate application.”).

Abbott also argues that the amendment is not narrowing because the applicant separately

disagreed with the merits of the examiner’s rejection. See Chang Dec., Exh. D at A-353–59. As

already noted, the applicant distinguished Weissman on the grounds that it suggests removing repeat

sequence probes from the mixture prior to hybridization, rather than using blocking DNA during

hybridization. See id. at A-355 (“prior to the filing of the grandparent to the present application in

January 1986, the direction of the art for unique sequence in situ hybridization involved careful

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selection of probes that did not contain repetitive sequences.”). The flaw in Abbott’s argument is

that the cited passage attempts to distinguish Weissman from the revised claim, 132, and not from

the previous claim 28. See id. at A-353 (“the following remarks will address only those rejections

which pertain to the new claims.”). In other words, the applicant felt it was necessary to distinguish

the prior art cited by the examiner even after filing revised claims. The applicant’s arguments are

not an attempt to preserve some of the scope of the previously rejected claims; thus the cancellation

of claim 28 and the submission of claim 132 constitutes a narrowing amendment. Specifically, the

submission of claim 132 presumptively narrowed the scope of the invention from “disabling the

hybridization capacity of repetitive sequences” using any means (as recited in claim 28) to using

“blocking nucleic acid” to accomplish the same function.

Having concluded that a narrowing amendment took place, the court must next consider

whether “the alleged equivalent was unforeseeable at the time the amendment was made, that the

alleged equivalent was tangential to the purpose of that amendment, or that there was some other

reason suggesting that the patentee could not reasonably be expected to have described the

insubstantial substitute in question.” See Terlep, 418 F.3d at 1385. Abbott argues that the purpose

of the amendment was “to pursue in separate applications claims involving other embodiments of

the invention that do not involve blocking.” Brief in Opposition at 23. While Abbott’s

characterization of the purpose may be valid when considered from the perspective of the applicant’s

attempts to pursue multiple patents on the same parent application, from the narrower vantage point

of the prosecution of the ‘841 patent, the purpose of the amendment was to overcome the examiner’s

rejections under sections 102 and 103. This purpose—to narrow the methods of eliminating repeat

sequences in order to avoid prior art—is directly related to the “blocking nucleic acid” limitation.

Abbott also argues that the critical distinction over the prior art was the use of “blocking”

generally rather than some other method of disabling hybridization, and did not depend on the

particular type of blocking used. Abbott argues that Insituform Technologies, Inc. v. CAT

Contracting, Inc., 385 F.3d 1360 (Fed. Cir. 2004) found an alleged equivalent to be only tangentially

related to the purposes of amendment under similar circumstances. In Insituform, the patent covered

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a method of repairing underground pipes by installing a liner inside the pipes. Id. at 1362–63. Prior

to installing the liner, the liner had to be filled with resin, which the claimed invention accomplished

through the use of a vacuum pump. Id. During prosecution of the patent, the claims were amended

to avoid prior art which located the vacuum pump at the end of the liner, but required the use of a

large vacuum pump as a result. Id. at 1370. The patentee added the requirement that the vacuum

pump use a single cup attached at the middle of the liner, rather than at the end. Id. The accused

product employed multiple cups, and the alleged infringer argued that the use of multiple cups was

disclaimed as a result of the narrowing amendment. Id. The Federal Circuit disagreed, holding that

the location of the vacuum pump at the center of the liner, rather than the number of vacuum cups,

provided the critical distinction over the prior art: “[t]here is no indication in the prosecution history

of any relationship between the narrowing amendment and a multiple cup process, which is the

alleged equivalent in this case.” Id. Thus the use of multiple cups was not disclaimed as part of the

narrowing amendment. Id.

Here, according to Abbott’s characterization, the focus of the narrowing amendment was on

the use of blocking. Blocking using unlabeled nucleic acid is a subspecies of blocking in general;

thus the specific choice of blocking agent is not unrelated to the use of blocking in the same way that

the number of vacuum cups is unrelated to the location of the vacuum. The exception applied in

Insituform Technologies is narrow, as the Supreme Court noted in Festo. A narrowing amendment

raises a presumption that the resulting element is confined to its literal scope. The presumption can

only be overcome by a showing 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, 535 U.S. at 741. Abbott has not demonstrated that it would have been

unreasonable or even difficult to claim the use of blocking generally, if, as Abbott claims, the use of

blocking provided the relevant distinction over the prior art. Blocking using PNA is thus excluded

from the scope of equivalents covered by the amended claim.

Dako’s motion for summary judgment of noninfringement of the ‘841 patent as to the HER2

and TOP2A products is therefore granted.

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III. Contributory and Induced Infringement

Abbott further alleges that Dako is secondarily liable for infringement of the patents under

principles of contributory and induced infringement. No contributory or induced infringement

exists, however, absent direct infringement by a third party. Here, with the exception noted above

for certain products under the ‘841 patent, use of the accused kits does not directly infringe either

asserted patent. Thus Abbott’s secondary liability arguments are unavailing.

CONCLUSION

For the foregoing reasons, the court GRANTS IN PART Dako’s motion for summary

judgment of noninfringement. As to the ‘479 patent, Dako’s motion is GRANTED in its entirety. 

As to the ‘841 patent, Dako’s motion is GRANTED for the HER2 and TOP2A products and

DENIED without prejudice for the remaining accused products.

IT IS SO ORDERED.

Dated: July 31, 2006 

MARILYN HALL PATEL

District Judge

United States District Court

Northern District of California

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1. The court points out that it is not the court’s responsibility to comb the record in search of

evidence or arguments not raised in the parties’ briefing. That is the lawyers’ job. Had this been

done in the claim construction phase this issue would have been resolved at that time—the proper

time—and would not need to be revisited here.

ENDNOTES

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