The Regents of the University of California and Abbott v. Dako (CAFC 2006-1334, 1452)

Northern California district court Judge Marilyn Patel had erroneously thought '479 anticipated by 841, its parent, but that was cleared up prior to appeal.

2-1 majority opinion penned by Judge Lourie; Judge Mayer riding shotgun. Judge Prost dissented.

There were three claim term contentions. First was "heterogeneous mixture of labeled unique sequence nucleic acid fragments," which the district court had ruled excluding repetitive sequences, thus providing the basis for noninfringement.

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 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.

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.

Prosecution history was dispositive.

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.

The patentees... were able to overcome... enablement rejection by limiting the heterogeneous mixture to unique sequences.

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.

That got Dako off the hook for '479.

The district court had granted noninfringement for '841 based upon the term 'blocking nucleic acid" having narrowed scope owing to prosecution estoppel, precluding infringement under doctrine of equivalents. On appeal, ace of spades Festo turned a shade of gray for the panel majority, because "the reason for the narrowing amendment was peripheral, or not directly relevant, to the alleged equivalent."

Appellants argue that the doctrine of prosecution history estoppel does not apply here because the "nucleic acid" limitation was never narrowed during prosecution. In 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.

"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).

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 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.

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.

A third term was left twisting in the claim construction DNA: ""morphologically identifiable cell nucleus." The district court had wrongly narrowed construction.

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.

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.

Preliminary injunction denial affirmed; noninfringement of '479 affirmed; '841 summary judgment noninfringement reversed on claim construction; remanded.

Judge Prost dissented "that the doctrine of equivalents is not precluded by prosecution history estoppel because the tangential exception applies." Tangentiality was cutting it too fine for Prost.

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 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).

"[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).