United States: Festo Redux: A Practioner´s Guide

Few patent law decisions in recent memory have generated as much debate as the Federal Circuit’s en banc decision in 2000 in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 234 F.3d 558 (Fed. Cir. 2000). The Federal Circuit held that the need for certainty and predictability in construing patent claims mandated that 1) prosecution history estoppel applies to all claim amendments made for a substantial reason relating to patentability, including amendments made to overcome non-prior art rejections, and 2) absolutely no range equivalence could be afforded to any such amended claim limitation. Immediately following the decision, most observers correctly predicted that the case was headed for Supreme Court review. After the Supreme Court's ruling in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., the patentee still has to overcome two hurdles in order to be successful in asserting equivalence of an amended claim limitation, but the second hurdle is no longer absolute and impenetrable. See 122 S. Ct. 1831, 1841-42 (2002). Thus, Festo eliminates the complete-bar rule established by the Federal Circuit in its en banc decision, but still leaves the patentee to overcome what is now a rebuttable presumption that he or she had surrendered the equivalent at issue. Id. at 1842.

The extent to which the presumption of estoppel can be overcome under the Supreme Court’s new standard will take years to become clear. For the patent prosecutor, the Supreme Court’s shift to a rebuttable presumption should not be viewed as a license to amend.9268553.1 without concern. Rebuttal of the presumption is not something that can be taken for granted. For the patent litigator, the Supreme Court has created a new set of challenges and opportunities.

Prosecution history estoppel is applied to preclude a range of equivalents which is given up during the patent amending process when the amendments were made in order to make the subject matter patentable. See Warner-Jenkinson, Inc. v. Hilton Davis Chemical, Co., 520 U.S. 17, 30-31 (1997). In Warner-Jenkinson, the Court held that when an amendment has been made to the patent claim that is not related to patentability, the patentee is not necessarily estopped from invoking the doctrine of equivalents. Id. at 33. In a case where it is not possible to tell whether or not the amendment has been made for a reason related to patentability, the Court held that it should be presumed "that the PTO had a substantial reason related to patentability for including the limiting element added by amendment." Id. The burden is on the patentee to rebut this presumption.¹ Id.

In determining how the patent practitioner should proceed post Warner-Jenkinson, the Court in a concurring opinion suggests how this should be handled. See id. at 41-42. (Ginsburg, J., concurring). Justice Ginsburg notes that in cases prior to Warner-Jenkinson, the patentee would not have had much reason to memorialize reasons for the claim amendment and the Court should keep that in mind as the patentee tries to establish reasons for why the amendment was made for a reason not substantially related to patentability. See id. This leads one to conclude that when future amendments are made, the patentee should make all efforts to state in the prosecution history the reason for the amendment and were appropriate, explain why it is not substantially related to patentability. While the prosecution history should be examined for determining the reason an amendment has been made to pre-Warner-Jenkinson patents, the courts should be flexible in determining what evidence to consider in order to rebut the substantially related presumption. See id. at 42 ("[O]n remand, the court can determine – bearing in mind the prior absence of clear rules of the game – whether suitable reasons for including the lower pH limit were earlier offered or, if not, whether they can now be established.").

The Federal Circuit followed Justice Ginsburg's concurrence and on remand allowed the district court wide latitude in to how to conduct the proceeding. See Hilton Davis Chemical Co. v. Warner-Jenkinson Co., 114 F.3d 1161, 1163 (Fed. Cir. 1997) (stating that "[t]he better course is to allow the district court to use its discretion to decide whether hearings are necessary or whether the issue can adequately be determined on a written record.").

Should the patentee be able to overcome the presumption that the change was made because of a substantial reason related to patentability, there will be no prosecution history estoppel, and the full range of equivalents will be available.

If the patentee's amendment is substantially related to patentability (or the patentee was unable to prove it was not), that does not necessarily mean prosecution history estoppel should apply. The Court has applied differing standards as to how a patent amendment should impact the application of prosecution history estoppel.

Prosecution history estoppel was developed to limit the doctrine of equivalents. As the Court stated, "[w]here the original [patent] application once embraced the purported equivalent but the patentee narrowed his claim to obtain the patent or to protect its validity, the patentee cannot assert that he lacked the words to describe the subject matter in question.". Festo, 122 S. Ct. at 1839. Prior to the Federal Circuit's Festo decision, the courts had followed a flexible-bar approach, examining on a case-by-case basis whether or not the patentee is estopped from claiming he or she did not give up the equivalent in question. Id. at 1840. The Federal Circuit in its en banc Festo decision adopted a complete-bar approach, finding any time a claim is amended, there is a complete bar to arguing the doctrine of equivalents for the amended claim limitation. Id.

When a patentee makes an amendment, he has "conceded an inability to claim the broader subject matter or at least [has] abandoned his right to appeal a rejection." Id. at 1840. This being said, the Court noted that under the flexible-bar regime, patentees who amended their patents did not expect this amendment to be interpreted as conceding all equivalents. Id. at 1841. Had patentees felt that by accepting this amendment they were conceding all equivalents, they may have appealed the PTO's decision. See id.

To be fair to patent practitioners who may have not wanted to concede all equivalents when making an amendment, the Court suggested imposing a presumption on the patentee similar to the Warner-Jenkinson presumption. See id. at 1841-42. The Court placed the burden on the patentee to "show[] that the amendment does not surrender the particular equivalent in question." Id. at 1842.

The Court listed three situations where it may be reasonable to believe that the patentee did not concede an equivalent: (1) where "the equivalent may have been unforeseeable at the time of the application;" (2) where "the rationale underlying the amendment may bear no more than a tangential relation to the equivalent in question;" or (3) where there is "some other reason suggesting that the patentee could not reasonably be expected to have described the insubstantial substitute in question." Id.

A reasonableness test is used to determine whether or not the amendment should have included the equivalent. See id. (noting that "[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.").

The United States, in an amicus brief cited with approval by the Court, see id., stated that the patentee should meet their burden "based on the patent prosecution record and relevant to the specific context of the infringement suit . . . ." Brief for the United States as Amicus Curiae Supporting Vacatur and Remand at 23, Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Co., 122 S. Ct. 1831 (2002) (No. 00-1543) [hereinafter Amicus Brief]. In particular, the showing should involve either:

Id. at 23 n.4. To determine the impact of Festo on the patent practitioner, this article separately examines each reason suggested by the Court to determine whether this issue could be decided based solely on the prosecution record, extrinsic evidence, or expert testimony.

A. Unforseeability: The Impact of New Technology
The underlying rationale behind prosecution history estoppel is that during the patent amendment process, the patentee conceded the equivalent in question. See Festo, 122 S. Ct. at 1840. When a new technology is developed that the patentee could not have foreseen, it is not rational to think that the patent holder had conceded that equivalent. See Amicus Brief, at 26 (noting that the patentee "should not be charged with such a surrender if the equivalent upposedly surrendered did not exist and was not reasonably within the contemplation of the PTO and the applicant at the time of the amendment.").

The Court alluded to the impact of new technology, and the fact that new technology could still be a non-conceded equivalent when it stated in Warner-Jenkinson that the time to measure equivalency of elements when applying the doctrine of equivalents is at the time of infringement. See Warner-Jenkinson, 520 U.S. at 320. Since equivalence is measured at the time of infringement, any subsequently developed technology can be examined for equivalence. Had the investigation been limited only to equivalents disclosed within the patent, new technologies deemed equivalent would be excluded from the doctrine. See id.

Presumably, any technology described in the specification or discussed in prosecution is, by definition, not after developed. Hence, while a patent prosecutor may be tempted to engage in expansive descriptions of the alternatives which may be used in place of the elements of the preferred embodiment, such an approach involves risk. A prosecutor’s speculative recitation of alternatives which are not well entrenched and known could result in technology which otherwise might be considered "after developed," being considered known and subject to estoppel.

Extrinsic evidence in the form of expert testimony from one skilled in the technology would be important to determine whether or not the equivalent was conceded. The expert would be able to testify as to whether or not the technology at issue was in existence during the time of the patent amendment process.

B. The Amendment Bears Only a Tangential Relationship to the Equivalent in Question.
Like a new technology that is unfo reseen at the time of the claim amendment, determining whether or not "the rationale underlying the amendment . . . bear[s] no more than a tangential relation to the equivalent in question," Festo, 1222 S. Ct. at 1842, will be something that the patent practitioner can do little to plan ahead for.

However, this is an area where the prosecution history should be valuable. The practitioner should have a thorough explanation in the prosecution history of why the claim was being amended, and this should establish a framework for determining whether or not there is a tangential relationship. It is "presumed the amended text was composed with awareness" of the presumption "and that the territory surrendered is not an equivalent of the territory claimed." Id. While a detailed prosecution history would not show that the equivalent was not intended to be surrendered, it would help to explain the reasons for the amendment and demonstrate if the reason was tangential to the equivalent being claimed.

C. Some Other Reason the Inconsequential Substitute Was Not Mentioned
Sometimes it may not be "possible for one of ordinary skill in the art to draft a claim amendment that literally encompassed the allegedly equivalent element while disclaiming the surrendered subject matter." Amicus Brief, at 26. Due to the complex nature of an amendment, a patentee may claim that it could not have been drafted with any greater particularity, however the court needs to determine if that is true. See id. at 27. A court can conduct this inquiry by comparing "the actual claim formulations that a person of ordinary skill in the art could have adopted to provide literal coverage of the alleged equivalent." Id.

This inquiry is likely going to involve the use of extrinsic evidence. If the equivalent was mentioned in the prosecution history, one would not have arrived at the inquiry concerning whether or not one of "ordinary skill in the art" could have drafted language which would have included this equivalent. The only advice to suggest to the practitioner is that the practitioner be as explicit as possible in the equivalents that are being conceded, and hope the case does not arise where the equivalent is not mentioned.

Festo appears to have changed the landscape in applying the doctrine of equivalents. To illustrate an exemplary Federal Circuit decision renedered between Warner-Jenkinson and the Festo en banc decision is examined in order to determine how it may have be handled in a post-Festo world.

In Litton Systems, Inc. v. Honeywell, Inc., 140 F.3d 1449 (Fed. Cir. 1998), defendant Honeywell tried to apply prosecution history estoppel to preclude Litton's use of the doctrine of equivalents regarding an ion beam source. See id. at 1458. During the patent amendment process, Litton had amended language calling for an ion beam source to a Kaufman-type ion beam source." Id. Applying Warner-Jenkinson using the prosecution history, the Federal Circuit determined that Litton "made its amendment for reasons related to patentability." Id. at 1458-61.

While prosecution history estoppel may apply, the court noted that "the standard for determining whether subject matter has been relinquished is whether one of ordinary skill in the art would objectively conclude from the prosecution history that an applicant surrendered it." Id. at 1462. There were several alternative structures Honeywell argued Litton was estopped from including. One structure, the duoplasmatron source, was listed in the prior art cited by the examiner when rejecting Litton's first patent claim. Id. After the rejection, Litton amended its claim to narrow it from being an "ion beam source" to a "Kaufman-type ion beam source." Id. The court noted that this narrowing, and the evidence in the record is sufficient to estop Litton from asserting the doctrine of equivalents for this issue. Id. Had Festo been decided, the outcome should be no different, as this is a clear case of prosecution history estoppel. Litton narrowed its claim for reasons related to patentability, and the claim language specifically narrowed the sources to exclude the duoplasmatron.

The Federal Circuit’s engaged in a different analysis of two other ion sources that Honeywell used, the hollow cathode or RF ion beam source. Id. at 1463. While the court noted that neither of these items was mentioned in the amendment, "this does not preclude estoppel." Id. The court remanded on this issue. See id. at 1464. Articles disclosed and distinguished by Litton during the patent process discussed beam sources that may have been similar to the Honeywell sources. See id. at 1463-64. If the differences between the disclosed ion sources and Honeywell's sources are trivial, then Litton would be estopped from arguing the doctrine of equivalents applied. See id. If they are not trivial, then prosecution history estoppel would not apply and the lower court would then examine if the doctrine of equivalents applies. See id. at 1464.

Following Festo, this second inquiry would become more complex. If the Honeywell beam source was not a trivial variation on the disclosed sources, in a post-Festo world, Litton would still be presumed to have surrendered this technology even if it would be considered an equivalent. See Festo, 122 S. Ct. at 1842. It will likely be very difficult in a post-Festo world to overcome the presumption. Since similar technology to the Honeywell sources appeared in the articles disclosed by Litton, it is unlikely the court would find that the equivalent was "unforeseeable at the time of the application." Id. Also, since the amendment revolved around ion beam sources, the amendment was "more than tangential[ly] relate[ed] to the equivalent in question." Id. The only possibility for Litton appears to be whether or not "there may be some other reason suggesting the patentee could not reasonably be expected to have described the insubstantial substitute in question." Id. In order to determine this, the court should examine whether someone with "ordinary skill in the art" could have drafted an amended claim would have encompassed the alleged equivalent. See Amicus Brief, at 27. Festo appears to have greatly narrowed the options which would have been available for Litton in asserting application of the doctrine of equivalents.

Honeywell made one final argument for finding application of prosecution history estoppel. See Litton Systems, 140 F.3d at 1464. Honeywell argued that since "one of ordinary skill in the art" knew that the Honeywell ion source could have been substituted for the Kaufman-type source, that knowledge should be imputed to Litton, and failure to mention the Honeywell source means it was an equivalent surrendered during the amendment process. Id. The Federal Circuit dispenses with that argument stating that "[t]o accept this argument would be essentially to accept the premise that when an applicant makes an amendment to an element to overcome the prior art, he has automatically surrendered all then-known substitutes to the amended element." Id. at 1464-65. However, Festo may cut contrary to this view. In Litton Systems, the court disagrees with imputing the knowledge of an ordinary person skilled in the art to the patent applicant because "[a]n applicant cannot surrender that which he does not know." Id. at 1465. However, if in Festo an equivalent could be surrendered if it was foreseeable at the time, Festo, 122 S. Ct. at 1842, hence effectively imputing the knowledge of an ordinary person to determine what was foreseeable. If it was foreseeable, the inquiry might turn to whether or not one skilled in the art could have drafted the amendment to include the Honeywell ion source. See Amicus Brief, at 27. Litton may have been presumed to have conceded the equivalent whether or not it was actually conceded.

The Litton Systems court stated that "[b]ecause the prosecution history is objective evidence of what knowledge the applicant has of the art, prosecution history estoppel should remain limited to the prosecution history." Litton Systems, 140 F.3d at 1465. However, while Festo may not be clear as to whether or not evidence from beyond the prosecution history can be used to determine whether prosecution history estoppel applies, the Amicus Brief, cited with approval by the Court, clearly supports the use of extrinsic evidence, including the use of expert testimony. Amicus Brief, at 23 n. 4.

It will undoubtedly take years for the repercussions of Festo to become clear. In the interim, here are some suggestions for consideration:

A. Avoid amending claims for any reason.

B. Thoroughly research the prior art before filing an application.

C. Draft a plethora of independent claims that encompass the entire spectrum of possible claims in breadth.

1. Include independent claims that clearly distinguish over the prior art even if they are narrow.

2. Beware of undue multiplicity rejections.

3. Any claims not pursued should be canceled without prejudice.

D. Draft claims so that they are divided into discrete elements, and, if they must be amended, do so by adding separate elements, if possible.

1. Only the added portion may be subject to the presumed bar.

E. Avoid making minor amendments to distinguish prior art cited by the Examiner where the rejection may be overcome by without amendment.

F. Where an independent claim is rejected based upon prior art, but a dependent claim is indicated by the Examiner to be allowable, the patentee should not amend the independent claim to include the additional limitations of the dependent claim. Instead, the patentee should cancel the independent claim and rewrite the dependent claim in independent form to retain the full benefit of the doctrine of equivalents.

G. Use means-plus-function claims since they have a statutorily mandated range of equivalents.

1. It may be possible to overcome a prior art rejection of a means-plus-function claim without having to amend it even though it would have been necessary to amend a corresponding claim not in means-plus- function format.

2. Include many alternative equivalent structures and multiple embodiments in the specification.

H. Conduct interviews with the Examiner before making any amendment that might be construed as having been made for a substantial reason related to patentability.

I. If claims must be amended for reasons other than substantial reasons related to patentability, carefully document the reason for making the amendment.

1. Always argue that an amendment does not narrow the claim element.

2. Always argue that an amendment was made for purposes unrelated to statutory concerns.

J. The claims of cases that originate in foreign countries should be amended before the U.S. application is filed.

K. When forced to amend claims in light of prior art, focus remarks on distinguishing the prior art rather than elaborating on the invention.