Full opinion text
MEMORANDUM OPINION AND ORDER REGARDING DEFENDANT’S MOTION FOR SUMMARY JUDGMENT REGARDING DOUBLE PATENTING AND PLAINTIFF’S MOTION TO REASSERT ’728 PATENT BENNETT, Chief Judge. TABLE OF CONTENTS I.INTRODUCTION.1073 A Procedural Background.1073 B.Factual Background.1075 1. The air ñlter indicator market.1075 2. EPC’s patents.1076 3. The stipulation regarding the ’728 patent.1079 II. DONALDSON’S SUMMARY JUDGMENT MOTION REGARDING OBVIOUSNESS-TYPE DOUBLE PATENTING.1082 A. Timeliness of the motion.1082 1. Arguments of the parties.1082 2. Analysis.1083 a. The applicable standard.1083 b. Application of the standards.1085 B. Effect Of The Stipulation And Representations On The Motion.1086 1. Donaldson’s representation concerning invalidity defenses to the ’456 patent.1086 2. Scope of the stipulation concerning the ’728 patent.1087 C. Standards For Summary Judgment .1088 D. Arguments Of The Parties.1089 E. Obviousness-type Double Patenting.1091 1. General principles.1091 2. The two-step analysis .1093 F. Step One: Claim Construction.1094 1. Claim 1 of each patent.1094 a. Side-by-side comparison.1094 b. Identifiable differences .1096 2. Claims 2 and 3 of the ’456patent.1097 a. Language of the claims.1097 b. Identifiable differences .1097 i. Construction of a means-plus-function claim.1098 ii. Construction of the means-plus-function claim here.1099 3. Summary of step one.1100 G. Step Two: Patentable Distinctions.1100 1. The two tests.1100 2. Recent applications.1101 a. In re Braat.1101 b. In re Goodman.1103 c. In re Emert.1103 d. In re Berg.1105 e. Eli Lilly.1107 3. The applicable test.1109 a. Could EPC have filed both sets of claims in one application?... .1109 b. Was the PTO solely responsible for any delay?.1110 4. Scope of the comparison .1111 a. Scope of comparison as framed by the parties.1112 b. Apparent uncertainty of the case law.1112 c. Consideration of other principles .1113 5. Are there patentable distinctions under the applicable test?.1115 a. The independent claims.1115 b. The dependent claims in light of the ’728 patent.1116 c. The impact of prior art.1118 i. Arguments of the parties.1118 ii. Authority to consider prior art.1118 Hi. Extent to which prior art should be considered.1120 d. Merits of the “prior art” arguments.1124 i. The prior art in question.1124 ii. Teachings of the’457patent.1126 Hi. Teachings of the’733 patent.1129 6. Summary of step two.1130 III. EPC’S MOTION TO REASSERT THE ’728 PATENT.1131 IV. CONCLUSION.1131 In this court’s somewhat limited experience with patent cases, it seems that the dispute between the parties often comes down to which party is trying to pound round pegs into square holes. Of course, the dispute may be complicated further by one party’s assertion that it is the pegs that are (or must be) square, while the holes are (or must be) round, inviting a rejoinder by the other party that round pegs and square holes would not be pat-entably distinct from square pegs and round holes, or that, even if one configuration didn’t anticipate, render obvious, or literally infringe the other, it would infringe the other under the doctrine of equivalents! However, where one issue is the judge-made doctrine of “obviousness-type double patenting,” as it is in this case, the Federal Circuit Court of Appeals has provided the lower courts with the following reminder: “In spite of the parties’ eagerness to conform the round-peg facts of the case into semantic, square holes, the critical inquiry remains whether the claims in [a later-issued patent] define an obvious variation of the invention claimed in [an earlier-issued] patent [to the same inventor].” See In re Emert, 124 F.3d 1458, 1462 (Fed.Cir.1997). Somewhat more specifically, this case involves the defendant’s contention that one patent for an air filter indicator device is invalid owing to obviousness-type double patenting over another patent to the same inventor, also for an air filter indicator device, which was filed later, but issued sooner. The defendant argues that it properly raised this contention within weeks of the scheduled trial, based on a “new” decision of the Federal Circuit Court of Appeals, Eli Lilly & Co. v. Barr Laboratories, Inc., 251 F.3d 955 (Fed.Cir. 2001), cert. denied, 534 U.S. 1109,122 S.Ct. 913, 151 L.Ed.2d 879 (2002), which the defendant contends “introduced a new application of the rule of obviousness-type double patenting.” The plaintiff disputes the defendant’s contention that the Eli Lilly decision requires invalidation of its later-issue patent, and also disputes whether the court should entertain the defendant’s double-patenting argument at all on the ground that it was untimely-raised. In the alternative, if its later-issued patent is invalidated, the plaintiff seeks leave to reassert claims alleging infringement of its earlier-issued patent, which the plaintiff had previously stipulated could be dismissed with prejudice. I. INTRODUCTION A. Procedural Background Former District Judge, now Circuit Judge, Michael Melloy, to whom this case was originally assigned, set the scene for the present litigation as follows: “In this patent infringement action, the plaintiff, Engineered Products Company (‘EPC’), asserts patent and trade dress claims against the defendant, Donaldson Company (‘Donaldson’), arising from Donaldson’s creation and sale of two air filter indicator devices — the Air Alert, sold from 1997 to 1999, and the NG Air Alert, sold from 1999 through the present.” Engineered Prods. Co. v. Donaldson Co., Inc., 165 F.Supp.2d 836, 841 (N.D.Iowa 2001). Two of EPC’s patents were originally at issue in this litigation, U.S. Patent Number 4,368,728 (the ’728 patent), issued on January 25, 1983, and U.S. Patent Number 4,445,456 (the ’456 patent), issued on May 1, 1984. Landmarks in the procedural history of this case include the following events. EPC filed its Complaint in this action on November 20, 1998, and Donaldson filed its Answer and Counterclaim on January 11, 1999. EPC then filed its Reply to Donaldson’s Counterclaim on February 1, 1999. Donaldson amended its Answer and Counterclaims on September 2, 1999, and EPC replied to the amended filings on October 6, 1999. Thereafter, the first truly significant occurrence in the procedural history of the case, for present purposes, ct least, occurred on July 28, 2000, when Judge Melloy set a so-called “Markman hearing” for September 21, 2000, and established deadlines for motions for summary judgment including any requests for claim construction. Cross-motions for summary judgment from the parties on a number of issues followed, and the “Mark-man hearing,” which included oral arguments on the cross-motions for summary judgment, took place as scheduled. Also, just shortly before the “Markman hearing,” on September 13, 2000, by stipulation of the parties, Donaldson filed a Second Amended Answer and Counterclaim to which EPC replied on October 10, 2000. On March 27, 2001, Judge Melloy rendered his opinion and order regarding the issues argued in the September 21, 2000, hearing. See Engineered Prods. Co. v. Donaldson Co., Inc., 165 F.Supp.2d 836 (N.D.Iowa 2001). In that ruling, Judge Melloy denied EPC’s motions for summary judgment as to various of Donaldson’s equitable and invalidity defenses; granted Donaldson’s motion for summary judgment on EPC’s trade dress claim; granted EPC’s motion for summary judgment as to Donaldson’s counterclaims alleging false advertising and unfair competition; granted EPC’s motion for summary judgment with regard to infringement of the ’456 patent by the original Air Alert; denied EPC’s motion for summary judgment with regard to infringement of the ’456 patent by the NG Air Alert; and denied Donaldson’s motion for summary judgment with regard to noninfringement of the ’456 patent by the NG Air Alert. By order dated June 11, 2001, Judge Melloy denied Donaldson’s motion to reconsider, in part, his construction of one element of the ’456 patent. Of even greater interest, however, than Judge Melloy’s ruling on these matters, for present purposes, was a stipulation regarding the ’728 patent during the “Mark-man hearing.” Pursuant to the parties’ stipulation, Judge Melloy ruled that “Count I and II of EPC’s Complaint, and Claim II of Donaldson’s counterclaim, are dismissed, with prejudice, as are any other claims or defenses of either party to the extent they rely upon the ’728 patent.” Engineered Prods. Co., 165 F.Supp.2d at 841 n. 1. Thus, following the parties’ stipulation and Judge Melloy’s ruling, only EPC’s claims of infringement of the ’456 patent and pertinent defenses remained at issue for trial. By order dated April 6, 2001, Judge Melloy set this matter for jury trial on January 29, 2002, and on December 20, 2001, he denied Donaldson’s motion to continue the trial. Nevertheless, this matter did not proceed to trial on January 29, 2002. Rather, on December 21, 2001, Donaldson filed the first of the motions presently pending before the court, its Motion for Summary Judgment Based on New Federal Circuit Case Law Re: Double Patenting, which diverted this matter from trial into consideration of another set of potentially dispositive motions. Donaldson’s motion is potentially disposi-tive of this action, without the need for trial, because Donaldson contends that the decision of the federal Circuit Court of Appeals in Eli Lilly & Co. v. Barr Laboratories, Inc., 251 F.3d 955 (Fed.Cir.2001), cert. denied, 534 U.S. 1109, 122 S.Ct. 913, 151 L.Ed.2d 879 (2002) — then almost seven months old — is “new” authority regarding obviousness-type double patenting, which, when applied to this case, requires invalidation of the only patent remaining at issue, the ’456 patent, thereby mooting the only remaining claims in this action, claims of infringement of the ’456 patent. Following a status hearing on January 4, 2002, on trial readiness and trial management issues, prompted in part by Donaldson’s summary judgment motion regarding double patenting, Judge Melloy orally continued the trial in this matter until further notice. By written order dated January 7, 2002, Judge Melloy memorialized his order to continue the trial and established a briefing scheduled on Donaldson’s summary judgment motion regarding double patenting. On January 23, 2002, EPC filed a resistance to Donaldson’s motion, and, in partial response to that motion, filed its own Motion To Reassert The ’728 Patent, which is also now pending before the court. In its motion, EPC argues that Donaldson’s motion for summary judgment relies on an unforeseen argument that the ’728 patent provides the basis for arguing obviousness-type double patenting as against the ’456 patent. In such circumstances, EPC contends that fairness and fundamental justice should allow EPC to reassert its ’728 patent, notwithstanding its prior stipulation to dismiss, with prejudice, claims regarding that patent. Thus, EPC’s motion might reanimate some claims for trial — claims based on the ’728 patent instead of the ’456 patent — even if Donaldson’s otherwise dispositive motion regarding double patenting is granted, thus eliminating claims based on the ’456 patent. Briefing on Donaldson’s summary judgment motion regarding double patenting and EPC’s motion to reassert the ’728 patent continued through the late winter and early spring of 2002. While those matters were pending, on December 28, 2001, Donaldson sought leave of court to file a Supplement To Second Amended Answer and Counterclaims in which Donaldson asserted new affirmative defenses of “patent misuse.” Such leave was granted on March 6, 2002. The Supplement did not, however, address the double-patenting defense injected into the litigation by Donaldson’s motion for summary judgment. On July 12, 2002 — after this case had been reassigned to the undersigned upon the elevation of Judge Melloy to the Eighth Circuit Court of Appeals — the court entered an order on various challenges that the parties had made to each other’s filings in support of or resistance to the “double patenting” and “reassertion” motions. In that order, .the court, inter alia, permitted each party to file a surre-ply brief addressing arguments of the opposing party on the motion for summary judgment and the motion to reassert the ’728 patent to which the briefing party believed that it had not yet had a fan-opportunity to respond. In the same order, the court also set the pending motions for oral arguments on August 22, 2002. Both EPC and Donaldson filed surreply briefs by the deadline of August 9, 2002, and the oral arguments took place as scheduled on August 22, 2002. At the oral arguments, plaintiff EPC was represented by Edward M. Laine of Oppenheimer Wolff & Donnelly, L.L.P., in Minneapolis, Minnesota. Defendant Donaldson was represented by Annamarie A. Daley and Ken R. Hall of Robins, Kaplan, Miller & Ciresi, L.L.P., in Minneapolis, Minnesota. The quality of both the briefing and oral arguments has been superb. Therefore, despite the complexity of some of the issues presented, the court finds that the parties’ positions have been clearly, effectively, and zealously presented. B. Factual Background Although one of the motions now pending before the court is a motion for summary judgment, and such motions ordinarily turn on the presence or absence of a genuine issue of material fact, the present factual summary does not attempt to identify all of the pertinent facts, let alone identify all of the factual disputes. Rather, it attempts to provide sufficient factual background to put in context the arguments of the parties on the pending motions. 1. The air filter indicator market In his ruling on the parties’ earlier cross-motions for summary judgment, Judge Melloy provided' sufficient statement of the factual background to this litigation to provide a general context to the parties’ claims. See Engineered Prods. Co., 165 F.Supp.2d at 843-44. The court will not repeat here that entire statement of the general factual background, but some summary is nevertheless appropriate. Suffice it to say that, in the mid-1970s, Joseph Nelson, of Waterloo, Iowa, one of the people who later incorporated EPC, invented a progressive air filter restriction indicator that allows the operator of a vehicle with a combustion engine to see how much restriction is present in the engine’s air filter without having to operate the vehicle at the same time. Nelson was eventually issued both the ’728 patent and the ’456 patent for air filter restriction indicating devices and assigned those patents to EPC. EPC marketed a successful line of products based on these patents. In the late 1970s, Donaldson began manufacturing and selling a competing line of air restriction indicators with a lock-up feature, but its products were consistently outsold by EPC’s. The present dispute was prompted, in part, by a decision of General Motors (GM) in the mid-1990s to add a progressive air filter restriction indicator to its light truck platform, the GMT-800 platform. This platform includes large passenger vehicles, such as SUVs, and hence, was expected to see enormous growth. EPC and Donaldson, the only domestic manufacturers of progressive air filter restriction indicators, competed for the contract to provide the required indicators. Donaldson eventually updated its product, at considerable expense, to produce the Donaldson Air Alert. Based on that upgraded design, Donaldson was awarded the GMT-800 contract. The Air Alert was manufactured and sold from 1997 to 1999, at which time it was replaced by the Next Generation Air Alert. However, on November 20, 1998, EPC filed the present action alleging that the Air Alert and NG Air Alert infringe its patents. 2. EPC’s patents Judge Melloy noted that Mr. Nelson was eventually issued the ’456 patent for his mechanical air filter restriction indicator with a lock-up feature on May 1, 1984. The Abstract to the ’456 patent describes the invention as follows: Am air filter restriction indicating device communicating with the supply of air passing from an air filter to the air intake of an internal combustion engine. The indicating device senses a decrease in the supply of air drawn through the air filter by the engine based upon changes in the amount of vacuum in the negative side of the air supply, the amount of restriction being indicated by the movement of an indicating device. Improved means included in the indicating device senses the movement of the indicating device and progressively locks the indicating device into various indicating positions as the vacuum increases due to an increased restriction of the filter, so that the maximum reading of restriction achieved during engine operation remains visible to the operator or maintenance personnel even after the engine is turned off. ’456 patent, Abstract (Donaldson Appendix, Exhibit 3). The patent has eight claims, of which claims 1 through 3 are of greatest interest in the present posture of the litigation. Claim 1 of the ’456 patent claims the structure of the indicating device, while claim 2, a dependent “means-plus-function” claim, claims “means for guiding the indicating member as the diaphragm moves between its infold position and its outfold position,” and claim 3, another dependent claim, claims a specific structure to perform the guiding function claimed in claim 2. See id., col. 7. 1. 56, to Col 8,1. 8. Although it was not relevant to the matters addressed in Judge Melloy’s ruling, because of the parties’ stipulation regarding the ’728 patent prior to that ruling, it is relevant here that Nelson had also previously been issued the ’728 patent, which is also a patent for an air filter restriction indicating device. The parties agree that, although it was issued first, on January 25, 1983, approximately fifteen months before the ’456 patent issued on May 1, 1984, the ’728 patent was actually an “improvement” patent on the ’456 patent. Indeed, Nelson, the inventor of both patents, described the ’728 patent in the Background Of The Invention as an “improvement” over air filter restriction indicating devices of which the inventor’s “co-pending application,” which ripened into the ’456 patent, was an example. See ’728 patent, col. 1, lines 5-21 (Donaldson’s Appendix, Exhibit 4). The Abstract to the ’728 patent describes the invention as follows: An improved air filter restriction indicating device is disclosed for use in connection with an internal combustion engine intake air filtration system. The improvement resides in a novel structure for resetting the indicating device which permits the indicating device to be reliably used in cold, wet environments and in particularly dirty, dusty environments. Id., Abstract. The precise improvements in the ’728 patent identified by the inventor were identified somewhat more extensively in the Background To The Invention as the inclusion of “a novel reset structure that prevents the structure from being rendered ineffective due to dirt and/or ice clogging [and the ability] to be mounted in any position, including in a vertically up position as well as in a vertically down position.” See id. at col. 1, line 44-51. Claim 1 of the ’728 patent varies but little from claim 1 of the ’456 patent, as indicated in a side-by-side comparison of claim language in Donaldson’s Appendix, which need not be repeated in full at this point in the present ruling. See Donaldson Appendix, Exhibit B. However, the ’728 patent does not expressly claim any “means for guiding the indicating member” as part of the invention, as do claims 2 and 3 of the ’456 patent. Rather, claims 2 through 5 of the ’728 patent are dependent claims claiming the “novel reset structure” that is the claimed improvement of the ’728 patent over existing air filter restriction indicating devices, such as the ’456 patent. See ’728 patent, claims 2-5. When presented side-by-side below, Figures 3 and 4 from each patent — which show the claimed air filter indicating device in each patent in infold and outfold positions — further demonstrate the similarity of the devices at issue, meaning “similarity” only from a layman’s perspective, at this point. Figure 5 from the ’728 patent, also presented below, on the other hand, “is a partially cutaway, exploded view showing the components of the novel resetting structure of the [’728] invention,” see ’728 patent, Brief Description Of The Drawings, col. 2,11. 13-15, which is included here to identify the claimed “improvement” embodied in the ’728 patent over existing air filter restriction indicating devices, such as the ’456 patent. six years to issue, the ’728 patent, for which an application had been filed more than three years later, was issued in just under While the ’456 patent took almost two years. Some of the events in the invention and prosecution of the two patents are also presented side-by-side below for comparison purposes. THE ’456 PATENT THE ’728 PATENT 06/19/78 Application Ser. No. 916,776 10/13/78 PTO rejection of all claims on prior art grounds 01/11/79 Request for extension of time 02/12/79 2nd request for extension of time, with conditional abandonment of application, and request for streamlined continuation, Application Ser. No. 011,410 07/02/79 PTO rejection of all claims on prior art grounds 09/27/79 Request for extension of time 11/01/79 Amendment cancelling pending claims and adding six claims 12/04/79 PTO allowance of amended claims and issuance of Notice of Allowance 03/18/80 Abandonment of allowed claims, request for filing of streamlined continuation, Application Ser. No. 131,456 10/02^80 Amendment adding six new claims 02/09/81 Application Ser. No. 232,422 02/17/81 PTO rejection of all pending claims “Co-pendency” period 05/18/81 Request for extension of time 06/16/81 Request for additional extension of time, conditional abandonment of application, and third streamlined continuation application, Application Ser. No. 273,699 01/23/83 The ’728 patent issued 03/31/83 PTO rejection of pending claims 1-18 06/ — /83 Request for 3 month extension of time until 09/30/83 09/29/83 Amendment 11/17/83 PTO Notice of Allowance of claims 19-26 02/17/84 Base issue fee paid 05/1/84 The ’456 patent issued To summarize this history, the ’456 patent took from the filing of the original application on June 19,1978, until May 1, 1984, to issue, owing to continuations and abandon-ments, but the 728 patent took only from the filing of an application on February 9, 1981, until January 25, 1983, to issue, with no continuations or abandonments noted in the patent. Therefore, the later-filed 728 “improvement” patent issued first, approximately fifteen months before the ’456 “basic” patent. 3. The stipulation regarding the ’728 patent Although EPC originally asserted claims of infringement of the 728 patent as well as the ’456 patent in this litigation, the 728 patent dropped out of this litigation as the result of a stipulation during the “Mark- man hearing.” Because EPC now seeks to reintroduce claims of infringement of the ’728 patent, it is well to review the parties’ stipulation and Judge Melloy’s resulting order regarding claims and defenses involving the ’728 patent. In the pertinent portion of the “Mark-man hearing,” the court and the parties first discussed a stipulation that Donaldson’s original Air Alert, which was marketed in 1997, is an infringing device, and that, if none of Donaldson’s other defenses to the validity of the ’456 patent is valid, Donaldson would owe EPC damages for such infringement, although there was no stipulation as to the measure of any such damages. See Transcript, Markman Hearing and Hearing on Summary Judgment Motions, 96-97. The court and the parties then turned to discussion of the stipulation regarding the ’728 patent, which is of interest here. That discussion consisted of the following: MS. DALEY [(Counsel for Donaldson)]: And there’s another stipulation that might make sense to put on the record with regard to the Next Generation device. Mr. Laine has agreed on behalf of EPC — correct me if I’m wrong, Mr. Laine — that they no longer are asserting the ’728 patent against the Next Generation Donaldson indicator and that they won’t sue us during the remaining months of the life of that patent. THE COURT: And I think there was something to that effect in one of the briefs. MR. LAINE [(Counsel for EPC)]: It’s in the briefs too, Your Honor. THE COURT: Is that the stipulation, Mr. Laine? MR. LAINE: That is we are relying exclusively on the ’456 patent on proving infringement with the second or Next Generation. THE COURT: And as I understand it — we will be getting into this in a little more detail in just a little bit, but Donaldson has this prior art defense to the ’728 patent, but as I understand it, they’ve never raised a prior art defense to the ’456 patent; is that right? MS. DALEY: We have a different invalidity defense. THE COURT: Your invalidity defense to the ’456 patent is, in essence, it was marketed more than a year prior to the patent date? MS. DALEY: Exactly, Your Honor. THE COURT: But the ’728 prior art defense is premised on ’456’s invalidity and that’s the prior art to the ’728; is that right? MS. DALEY: The ’728 patent invalidity, Your Honor, is not premised on invalidity of the ’456 patent. THE COURT: But I thought the report — if I read it correctly — said that some of the prior arts of the ’456 patent— MS. DALEY: Right. And so the ’456 patent — the fact is that the Filter Minder was out in the marketplace for sale more than one year before the filing date of the ’728 patent. THE COURT: But it’s the same facts; right? I mean basically if the ’456 patent is valid, then you don’t have a prior art defense to the ’728 patent; right? MS. DALEY: No, that’s not correct, Your Honor. Even if the ’456 patent is valid, we would still have an invalidity argument on the ’728 patent. THE COURT: Well— MS. DALEY: And Mr. Hall is going to make that argument. Maybe he can explain it to you. THE COURT: Well, I guess if they’re not suing on the ’728 patent, do we have to get into the invalidity of the ’728? MS. DALEY: But they still have the ’728 seeking damages on the original indicator, Your Honor; on — under the ’728 patent. THE COURT: Well, what difference — I guess now I’m — I guess now I’m confused. What difference does that make which of your two patents it infringes if they’re willing to stipulate they’re infringing the ’456? MR. LAINE: It really has no material consequences in terms of the remedy that we can recover unless Donaldson is going to try and later argue that they’re the prevailing party; that they somehow are defeating the ’728 patent, but since we’re not relying on it for the second generation device and since it’s stipulated that the ’456 is infringement first [sic (infringed by the first device?) ], it really has no practical consequence anymore and probably can dispense of it [sic], THE COURT: What is the practical consequences [sic] of the validity or invalidity of the ’728? MS. DALEY: Only if they’re seeking damages against us, Your Honor. And again, we already have the stipulation on the record with respect to future sales. So if Mr. Laine is willing to stipulate to a dismissal of the ’728 patent infringement claim against the original indicator, it’s no longer an issue. MR. LAINE: I wish I could drop it, Judge. THE COURT: And you’re stipulating that this did infringe the ’456? MS. DALEY: The original indicator, subject to our defenses, yes, Your Hon- or. THE COURT: All right. You are not going to sue as to the ’728; is that right, Mr. Laine? MR. LAINE: We’re not going to sue as to the ’728 as [to (?) ] the second device. We really don’t need to as to the first and we would be content to rely on the ’456 and withdraw that claim with the understanding that Donaldson would then withdraw its validity defenses that relate to that so that the whole thing is just gone for both sides and in an equal fashion. THE COURT: Is that agreeable? MS. DALEY: I think that’s the most sufficient [sic] use of everyone’s resources. THE COURT: All right. Then let’s move on to talk — well, I guess it seems to me probably the next thing to talk about is the validity of the ’456. MS. DALEY: And I understand then what EPC has done is it’s stipulated to a dismissal with prejudice of the ’728 patent in this lawsuit? MR. LAINE: Yes. THE COURT: With the understanding that any attack in affirmative defense or counterclaim or otherwise that relates to its validity is withdrawn as well. MS. DALEY: Yes, Your Honor. THE COURT: All right. So that will be so ordered then. Transcript, Markman Hearing and Hearing on Summary Judgment Motions, at 98-102. In his ruling following the “Markman hearing,” Judge Melloy described the parties’ stipulation regarding the ’728 patent, and the effect of that stipulation, as follows: This action originally involved allegations by EPC that Donaldson’s products infringed two EPC patents: U.S. Patent No. 4,368,728 (“the ’728 patent”), issued on January 25, 1983, and U.S. Patent No. 4,445,456 (“the ’456 patent”), issued on May 1, 1984. At oral argument, both parties agreed to withdrawal with prejudice of any claims or defenses based on the ’728 patent. Accordingly, Count I and II of EPC’s Complaint, and Claim II of Donaldson’s counterclaim, are dismissed, with prejudice, as are any other claims or defenses of either party to the extent they rely upon the ’728 patent. Engineered Prods. Co., 165 F.Supp.2d at 841 n. 1. However, the parties now dispute' — among many other things — the accuracy of Judge Melloy’s characterization of their stipulation regarding the ’728 patent, the effect of the stipulation on their claims and defenses, and whether the stipulation and portion of Judge Melloy’s order pursuant to that stipulation should now be set aside upon EPC’s motion to reassert the ’728 patent. As noted above, there are two motions pending before the court: Donaldson’s December 21, 2001, Motion for Summary Judgment Based on New Federal Circuit Case Law Re: Double Patenting, and EPC’s January 23, 2002, Motion To Reassert The ’728 Patent, which was filed as a partial response to Donaldson’s motion regarding double patenting. Although EPC’s motion is not expressly contingent upon the granting of Donaldson’s motion, it is offered “in partial response” to Donaldson’s motion. Thus, the court deems it appropriate to begin its legal analysis with Donaldson’s motion for summary judgment, then consider EPC’s motion to reassert the ’728 patent only to the extent that it may be necessary to do so in light of its disposition of Donaldson’s summary judgment motion. II. DONALDSON’S SUMMARY JUDGMENT MOTION REGARDING OBVIOUSNESS-TYPE DOUBLE PATENTING A. Timeliness of the motion Before considering the merits of Donaldson’s summary judgment motion regarding double patenting, the court must first take up the procedural issue of the timeliness of that motion. This is so, because the motion was filed on the eve of trial, and because EPC has asserted that the untimeliness of the summary judgment motion is a sufficient, independent ground for denying it, without regard to the merits. 1. Arguments of the parties In its opening brief in support of its summary judgment motion regarding double patenting, Donaldson contends that the court should entertain the motion, even though it was filed just over a month before this case was scheduled to go to trial, and well after the dispositive motion deadline embodied in Judge Melloy’s order setting a “Markman hearing” and deadlines for summary judgment motions, because Donaldson’s latest summary judgment motion seeks to invalidate the lone patent still at issue, the ’456 patent, based on “new” Federal Circuit case law. Donaldson identifies that “new” authority as the decision of the Federal Circuit Court of Appeals in Eli Lilly & Co. v. Barr Laboratories, Inc., 251 F.3d 955 (Fed.Cir.2001), cert. denied, 534 U.S. 1109, 122 S.Ct. 913, 151 L.Ed.2d 879 (2002). However, in its resistance to Donaldson’s motion, EPC argues that the motion was filed on the eve of trial, without any prior hint that double patenting was at issue in this case. EPC argues, further, that Donaldson did not plead any affirmative defense of obviousness-type double patenting and had never identified that ground for invalidity of the ’456 patent in answer to any interrogatories regarding its claims or defenses. Thus, EPC argues that Donaldson waived any defense premised on double patenting. Moreover, EPC argues that the decision in Eli Lilly was handed down several months before Donaldson ever asserted the purported dispos-itive impact of that decision on this case, and that the Eli Lilly decision neither stated a new rule nor overruled prior precedent on double patenting. In these circumstances, EPC argues that the Eli Lilly decision provides little excuse for the untimely assertion of arguments based on double patenting. “In short,” EPC summarizes, “if the concept of untimeliness can ever prevent the last minute assertion of claims or defenses, that concept is properly applied here.” EPC’s Brief Resisting Donaldson’s Motion for Summary Judgment on Double Patenting at 18. In reply, Donaldson argues that it never waived a double-patenting defense, because it alleged, generally, that the ’456 patent is invalid, it reserved the right to assert additional grounds for invalidity in its Second Amended Answer and Counterclaims, and it included a reference to the ’728 patent as a basis for invalidating the ’456 patent in its timely Notice pursuant to 35 U.S.C. § 282. Furthermore, Donaldson contends that, during a case management conference, it promptly notified the court of the Eli Lilly decision “as soon as Donaldson became aware of this new case law,” and that it then filed its summary judgment motion based on the Eli Lilly decision just two days after the conference. Finally, Donaldson asserts that it will be prejudiced if it is not permitted to present invalidating prior art, particularly when the issue is supported only by new case law. In its surreply brief, which the undersigned specifically authorized to address arguments to which a party believed that it had not yet had a fair opportunity to respond, EPC contends that Donaldson’s argument that it could not have asserted a double-patenting argument before the Eli Lilly decision was handed down is “disingenuous.” This is so, EPC contends, because Donaldson in fact relies on older cases to assert that the applicable test of double patenting, under the circumstances presented here, is the one-way test later applied in Eli Lilly, demonstrating that the Eli Lilly decision presents nothing “new.” 2. Analysis a. The applicable standard Notwithstanding'—and not finding persuasive'—Donaldson’s assertions that its existing pleadings and answers to interrogatories were sufficient to put EPC on notice of the possibility of a double-patenting defense to the ’456 patent, the court concludes that the appropriate standard against which to judge the timeliness or untimeliness of Donaldson’s motion for summary judgment regarding double patenting is the standard applicable to belated amendments to assert a new defense. This is so, because whatever the manner in which double patenting has been asserted in this litigation, the effect of Donaldson’s motion is to inject—for the first time or by way of an unforeseen clarification—an invalidity defense heretofore not contemplated or addressed by the parties. Rule 15 of the Federal Rules of Civil Procedure provides that, except in circumstances not presented here, amendments of pleadings are permitted as follows: [A] party may amend the party’s pleading only by leave of court or by written consent of the adverse party; and leave shall be freely given when justice so requires. Fed. R. Civ. P. 15(a). In Foman v. Davis, 371 U.S. 178, 83 S.Ct. 227, 9 L.Ed.2d 222 (1962), the Supreme Court stated, In the absence of any apparent or declared reason—such as undue delay, bad faith or dilatory motive on the part of the movant, repeated failure to cure deficiencies by amendments previously allowed, undue prejudice to the opposing party by virtue of allowance of the amendment, futility of amendment, etc. — the leave sought should as the rules require, be “freely given.” Foman, 371 U.S. at 182, 83 S.Ct. 227. Not only is the language of Rule 15(a) and precedent of the Supreme Court and the Federal Circuit Court of Appeals pertinent to the issue of belated assertion of a defense, but the Federal Circuit Court of Appeals has explained that amendment of pleadings is “ ‘a subject which is not unique to patent law, [so that] we look to the law of the regional circuit.’ ” Data-scope Corp. v. SMEC, Inc., 962 F.2d 1043, 1045 (Fed.Cir.1992) (quoting Kalman v. Berlyn Corp., 914 F.2d 1473, 1480 (Fed. Cir.1990)). Thus, this court may also properly consider Eighth Circuit standards for amendment of pleadings under Rule 15(a). Expounding upon the language of Rule 15(a) and the interpretation of that Rule by the Supreme Court in Foman, the Eighth Circuit Court of Appeals has explained, “ ‘Only limited circumstances justify a district court’s refusal to grant leave to amend pleadings: Undue delay, bad faith on the part of the moving party, futility of the amendment or unfair prejudice to the opposing party.’ ” Costello, Porter, Hill, Heisterkamp & Bushnell v. Providers Fidelity Life Ins. Co., 958 F.2d 836, 839 (8th Cir.1992) (quoting Sanders v. Clemco Indus., 823 F.2d 214, 216 (8th Cir. 1987), in turn citing Foman v. Davis, 371 U.S. 178, 182, 83 S.Ct. 227, 9 L.Ed.2d 222 (1962)). More recently, the Eighth Circuit Court of Appeals affirmed denial of leave to amend on grounds of prejudice to the non-movant and undue delay in seeking to amend, finding that the district court had appropriately considered the following factors: “(1) almost a year had passed since the deadline for amending claims when [the movant] sought leave to amend; (2) extensive discovery had been conducted and had closed; and (3) dispositive motions had been filed and were pending before the court.” Deutsche Financial Services Corp. v. BCS Ins. Co., 299 F.3d 692, 700 (8th Cir.2002). The Federal Circuit Court of Appeals also has not been silent on the effect of “undue delay” on leave to amend pleadings: Notwithstanding the view that Fed. R.Civ.P. 15(a) is to be construed liberally, courts have not hesitated to deny motions to amend that have been filed after significant delay. Delay alone, even without a demonstration of prejudice, has thus been sufficient grounds to deny amendment of pleadings. In some cases it has been held important in determining the propriety of the motion for leave to amend whether prejudice would result to the nonmoving party. Senzar-Gel Corp. v. Seijfhart, 803 F.2d 661, 666, 673 (Fed.Cir.1986) (citations omitted) (Bennett, J., dissenting). According to Wright and Miller, “[T]he risk of substantial prejudice increases with the passage of time.” 6 Wright & Miller & Kane, Federal Practice and Procedure § 1488 at 439 (1971). The Fifth Circuit stated in Chitimacha [Tribe of Louisiana v. Harry L. Laws Co., 690 F.2d 1157, 1163 (5th Cir.), cert denied, 464 U.S. 814, 104 S.Ct. 69, 78 L.Ed.2d 83 (1983) ], “[m]ere passage of time need not result in a denial of leave to amend, but delay becomes fatal at some period of time” (citing Gregory v. Mitchell, 634 F.2d 199, 203 (5th Cir. 1981)) (in light of significant delay — 21 months from filing of original complaint — and the fact that the tribe failed to cure deficiencies in earlier amendments, denial of the tribe’s motion to amend was not an abuse of discretion); see Woodson v. Fulton, 614 F.2d 940, 943 (4th Cir.1980) (leave to amend “may be denied for undue delay”). s¡t Hs ‡ ❖ # ... Thus, with the passage of time and acceptance of multiple earlier amendments, a point is reached when the party seeking to amend must justify that request by more than invocation of the concept of the rule’s liberality. • Te-Moak Bands of Western Shoshone Indians of Nevada v. U.S., 948 F.2d 1258, 1262-63 (Fed.Cir.1991) (emphasis added) (non-patent case). Thus, the court in Te-Moak Bands focused on the undue delay, standing alone, and the effect of undue delay in terms of risk of prejudice to the non-movant. On the other hand, in a prior decision, Cornwall v. U.S. Construction Manufacturing, Inc., 800 F.2d 250 (Fed. Cir.1986)— a patent case upon which both parties here rely, although they extract from it diametrically opposed principles—the Federal Circuit Court of Appeals also recognized that a court must consider the risk of prejudice to the movant of denial of leave to amend. Relying on Eleventh Circuit precedent, the court in Cornwall reversed a district court’s denial of leave to amend the defendant’s answer to assert patent invalidity. See Cornwall, 800 F.2d at 252-53. After emphasizing “the importance of considering what effect the denial of a motion to amend would have on the mov-ant,” noting that the district court had failed to offer “any justifying reason” for denying leave to amend, and finding that it appeared that the movant would be prejudiced by denial of leave to amend its answer to assert a defense of patent invalidity, the appellate court reversed the district court’s denial of leave to amend. See Cornwall, 800 F.2d at 253. b. Application of the standards Here, the court finds little justification for Donaldson’s failure to assert double patenting as a ground for invalidity of the ’456 patent well before it did so, even if the Eli Lilly decision first made Donaldson aware of the availability of a double-patenting defense to the ’456 patent. See Foman, 371 U.S. at 182, 83 S.Ct. 227 (considering the movant’s “undue delay” as a ground for denying leave to amend); Costello, 958 F.2d at 839 (same);' Te-Moak Bands, 948 F.2d at 1262-63 (same). This is so, because the issue of double-patenting was not newly minted by the Eli Lilly decision; Donaldson only asserted that issue long after the dispositive motion deadline set by Judge Melloy, and well after the parties had completed extensive discovery; Donaldson had twice previously amended its answer and counterclaims without asserting the double-patenting issue; and, as noted above, the Eli Lilly decision was handed down on May 30, 2001, almost seven months before Donaldson filed its motion relying upon that decision on December 21, 2001. Cf. Deutsche Fin. Seros. Corp., 299 F,3d at 700 (considering the following factors: (1) considerable time had passed since the deadline for amending claims before the movant sought leave to amend; (2) extensive discovery had been conducted and had closed; and (3) dispositive motions had been filed and were pending before the court). Thus, there is some smack of gamesmanship in the timing of Donaldson’s motion several months after the decision upon which it relies was handed down, but only a little over a month before trial was set to begin. However, the dispositive issue here is a balance of prejudice to the parties that would arise from either considering or refusing to consider the double-patenting issue. Compare, e.g., Te-Moak Bands, 948 F.2d at 1262-63 (considering prejudice to the non-movant), with Cornwall, 800 F.2d at 253 (considering prejudice to the mov-ant). On the one side of the scales, the possible prejudice to Donaldson from refusing to hear its defense of patent invalidity, however belatedly that defense was asserted, is substantial. Cf Cornwall, 800 F.2d at 253 (concluding that it “appear[ed]” that the movant was prejudiced by denial of leave to assert a patent invalidity defense). On the other side of the scales, any prejudice to EPC from the belated assertion of the double-patenting defense has been largely cured: EPC was not required to address the defense upon short notice at trial, because Judge Melloy continued the trial, and EPC has had the opportunity to present a full resistance to Donaldson’s motion for summary judgment. Under the circumstances presented here, where the patents at issue have already expired, thus fixing the limits on the period during which any infringement and damages must be determined, the delay of the trial itself cannot be considered “prejudice” to EPC. Therefore, while not condoning such belated assertion of a defense—and particularly a patent invalidity defense—that could reasonably have been asserted sooner, the court will consider Donaldson’s motion as the only means of curing potential prejudice to Donaldson arising from inability to assert a defense of patent invalidity, while imposing no significant prejudice upon EPC. Couched in terms of the standards stated in Rule 15(a), the court concludes that “justice ... requires” consideration of Donaldson’s belated summary judgment motion asserting the defense of double patenting. B. Effect Of The Stipulation And Representations On The Motion Another procedural impediment to consideration of Donaldson’s motion for summary judgment must also be considered before the court can turn to the merits of that motion. Although EPC does not expressly argue that Donaldson’s summary judgment motion regarding double patenting is contrary to the parties’ stipulation to dismiss claims and defenses relating to the ’728 patent, EPC does argues, inter alia, that Donaldson has “reversed field” on a representation, made in connection with the stipulation during the “Mark-man hearing,” that Donaldson’s only invalidity defense to the ’456 patent was that the invention was marketed more than a year prior to the patent application. Donaldson argues that this so-called representation referred only to the invalidity defenses to the ’456 patent then before the court on summary judgment, not to any and all invalidity defenses that Donaldson had ever asserted or could ever assert. The court deems it appropriate to consider, at least briefly, whether Donaldson’s motion for summary judgment on double patenting is barred either by the parties’ stipulation regarding the ’728 patent or by Donaldson’s “representation” about its invalidity defenses to the ’456 patent. 1. Donaldson’s representation concerning invalidity defenses to the ’456patent First, the “representation” regarding invalidity defenses to the ’456 patent upon which EPC relies arises from the following exchange: THE COURT: And as I understand it — we will be getting into this in a little more detail in just a little bit, but Donaldson has this prior art defense to the ’728 patent, but as I understand it, they’ve never raised a prior art defense to the ’456 patent; is that right? MS. DALEY [(for Donaldson)]: We have a different invalidity defense. THE COURT: Your invalidity defense to the ’456 patent is, in essence, it was marketed more than a year prior to the patent date? MS. DALEY: Exactly, Your Honor. Transcript, Markman Hearing and Hearing on Summary Judgment Motions, p. 98, ll. 10-22. The court finds that the representation by Donaldson’s counsel unambiguously referred only to invalidity defenses then at issue. Although the representation could, perhaps, be construed as an abandonment of any of the other invalidity defenses that Donaldson had already pleaded or had identified in response to EPC’s interrogatories — a matter the court need not decide at this point — it cannot be read as foreclosing Donaldson from asserting an invalidity defense it had not previously asserted. The court resolved, above, the question of whether Donaldson should now be permitted to inject such a new defense into this litigation, under a Rule 15(a) standard, concluding that Donaldson could do so. 2. Scope of the stipulation concerning the ’728 patent Nor does the stipulation concerning the ’728 patent itself bar Donaldson from asserting an invalidity defense to the ’456 patent based on the ’728 patent, such as a defense of obviousness-type double patenting. This court recognizes that Judge Melloy’s summary or characterization of the stipulation in his ruling on the parties’ cross-motions for summary judgment might suggest such a bar, because his characterization was as follows: At oral argument, both parties agreed to withdrawal with prejudice of any claims or defenses based on the ’728 patent. Accordingly, Count I and II of EPC’s Complaint, and Claim II of Donaldson’s counterclaim, are dismissed, with prejudice, as are any other claims or defenses of either party to the extent they rely upon the ’728 patent. Engineered Prods. Co., 165 F.Supp.2d at 841 n. 1 (emphasis added). However, the stipulation that was actually entered on the record was not quite so broad, or, to put it another way, Judge Melloy’s characterization must be read in light of the actual stipulation on the record. The transcript of the stipulation, which is quoted more fully supra, in Section I.B.3., indicates that the parties recognized that the claims as to which the stipulation regarding the ’728 patent applied were EPC’s claims of infringement of that patent by Donaldson’s devices, which were asserted in Counts I and II of EPC’s Complaint, and Donaldson’s defenses asserting the invalidity of the ’728 patent. Near the end of the discussion of the parties stipulation regarding the ’728 patent, the following exchange occurred: THE COURT: All right. You are not going to sue as to the ’728; is that right, Mr. Laine? MR. LAINE [ (for EPC) ]: We’re not going to sue as to the ’728 as [to (?) ] the second device. We really don’t need to as to the first and we would be content to rely on the ’456 and withdraw that claim with the understanding that Donaldson would then withdraw its validity defenses that relate to that so that the whole thing is just gone for both sides and in an equal fashion. THE COURT: Is that agreeable? MS. DALEY: I think that’s the most sufficient [sic] use of everyone’s resources. Transcript, Markman Hearing and Hearing on Summary Judgment Motions, at p. 101, ll. 7-19. EPC’s counsel’s references to its patents in relation to Donaldson’s “first” and “second” devices, in the context presented immediately above and upon consideration of the fuller context of the entire discussion of the stipulation, plainly were references to EPC’s claims of infringement of the ’728 patent by those devices, while his reference to “validity defenses that relate to that” plainly refers to validity defenses to the ’728 patent. Before the court moved on to other matters in the “Markman hearing,” counsel for Donaldson sought some clarification of the stipulation, as follows: MS. DALEY: And I understand then what EPC has done is it’s stipulated to a dismissal with prejudice of the ’728 patent in this lawsuit? MR. LAINE: Yes. THE COURT: With the understanding that any attack in affirmative defense or counterclaim or otherwise that relates to its validity is withdrawn as well. MS. DALEY: Yes, Your Honor. THE COURT: All right. So that will be so ordered then. Transcript, Markman Hearing and Hearing on Summary Judgment Motions, at p. 101, l. 24, to p. 102. 1. 9 (emphasis added). While Donaldson’s counsel’s question is overbroad, in the sense that it does not specify claims of infringement of the ’728 patent, but instead refers to “dismissal with prejudice of the ’728 patent in this lawsuit,” the question sought clarification of what claims involving the ’728 patent EPC had agreed to dismiss. Again, the only claims involving the ’728 patent that EPC had asserted were claims that Donaldson’s devices infringed that patent as well as the ’456 patent. Thus, no ambiguity arises from Donaldson’s counsel’s question. On the other hand, the court’s characterization of the tradeoff clearly demonstrates that the affirmative defenses and counterclaims that Donaldson was stipulating would be dismissed related to the “invalidity” of the ’728 patent, not the ’456 patent. The court concludes that neither the parties’ stipulation nor the representation by Donaldson’s counsel during the “Mark-man hearing” stands as a bar to Donaldson’s present assertion of a motion for summary judgment on the ground that the ’456 patent is invalid owing to obviousness-type double patenting in light of the ’728 patent. Therefore, the court may turn to consideration of the merits of that summary judgment motion. C. Standards For Summary Judgment Analysis of the merits of Donaldson’s motion begins with the standards applicable to a motion for summary judgment. Rule 56 of the Federal Rules of Civil Procedure, which governs motions for summary judgment, states, in pertinent part, the following: Rule 56. Summary Judgment (b) For Defending Party. A party against whom a claim ... is asserted ... may, at any time, move for summary judgment in the party’s favor as to all or any part thereof. (c) Motions and Proceedings Thereon.... The judgment sought shall be rendered forthwith if the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, 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(b)-(e) (emphasis added). Thus, as the plain language of the rule indicates, the appropriateness of summary judgment ordinarily turns on whether or not there are genuine issues of material fact that must be resolved by the trier of fact. “A genuine issue exists if the evidence is such that a reasonable jury could find for the nonmoving party.” Eli Lilly, 251 F.3d at 962 (citing Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986)). “A disputed fact is material if it might affect the outcome of the suit such that a finding of that fact is necessary and relevant to the proceedings.” Id. (again citing Anderson, 477 U.S. at 248, 106 S.Ct. 2505). “While the burden rests on the party moving for summary judgment to show ‘that there, is an absence of evidence to support the non-moving party’s case,’ the nonmoving party must affirmatively demonstrate by specific factual allegations that a genuine issue of material fact-exists for trial.” Id. at 971 (quoting Celotex Corp. v. Catrett, 477 U.S. 317, 322-23,106 S.Ct. 2548, 91 L.Ed.2d 265 (1986)). In reviewing the record, the court must view all the facts in the light most favorable to the nonmoving party and give that party the benefit of all reasonable inferences that can be drawn from the facts. See Matsushita Elec. Indus. Co. v. Zenith Radio Corp., 475 U.S. 574, 587, 106 S.Ct. 1348, 89 L.Ed.2d 538 (1986). On the other hand, questions of law are particularly amenable to summary judgment precisely because they do not turn on factual disputes. See, e.g., Varilease Technology Group, Inc. v. U.S., 289 F.3d 795, 798 (Fed.Cir.2002) (contract interpretation, as a question of law, is amenable to summary judgment); Gentex Corp. v. Donnelly Corp., 69 F.3d 527, 530 (Fed.Cir.1995) (patent claim interpretation, as a question of law, is amenable to summary judgment). Double patenting, which is at issue in Donaldson’s motion for summary judgment, is a question of law for the court, see, e.g., Georgia-Pacific Corp. v. United States Gypsum Co., 195 F.3d 1322, 1326 (Fed.Cir. 1999), as amended on denial of rehearing and rehearing en banc, 204 F.3d 1359 (Fed.Cir. Feb.23, 2000), cert. denied, 531 U.S. 816, 121 S.Ct. 54, 148 L.Ed.2d 22 (2000), as is the determination of whether a “one-way” or “two-way” test of double patenting is appropriate. See In re Emert, 124 F.3d 1458, 1460 (Fed.Cir.1997). Nevertheless, the legal question of which test of double patenting applies may depend upon specific findings of fact. See id. Therefore, this aspect, at least, of Donaldson’s motion for summary judgment regarding double patenting may be subject to genuine issues of material fact, notwithstanding that the ultimate questions of what test applies and whether there was double patenting are questions of law. Moreover, other legal determinations in the double-patenting analysis may also be subject to genuine issues of material fact. Cf. Eli Lilly, 251 F.3d at 971-72 (noting that there were no genuine issues of material fact as to whether fluoxetine hydrochloride inhibits the uptake of serotonin in animals, or that human is a species of the animal genus, such that the double-patenting issue in that case was “solely a matter of law”). I). Arguments Of The Parties In support of its motion for summary judgment, Donaldson contends that, in Eli Lilly & Co. v. Barr Laboratories, Inc., 251 F.3d 955 (Fed.Cir.2001), cert. denied, 534 U.S. 1109, 122 S.Ct. 913, 151 L.Ed.2d 879 (2002), the Federal Circuit Court of Appeals “introduced a new application of the rule of obviousness-type double patenting.” Specifically, Donaldson contends that, in Eli Lilly, the court held that if a later-filed, but earlier-issued patent anticipates or renders obvious an earlier-filed, but later-issued patent, and the same party holds the rights to both patents, the earlier-filed patent is invalid. Donaldson contends that, before the Eli Lilly decision, the rule was, “ ‘When a basic patent is filed before but issued after an improvement patent, the order of issuance is disregarded and the later-issuing patent is upheld if the improvement patent is not obvious in light of the basic patent.’ ” Donaldson’s Brief in Support of Motion for Summary Judgment Based on New Federal Circuit Case Law Re: Double Patenting at 6 (quoting 3 D. Chisum, Patents, § 9.03[2][c] (2000)). Donaldson contends, “With its decision in Eli Lilly & Co. v. Barr Laboratories, Inc., 251 F.3d 955 (Fed.Cir.2001), [cert. denied, 534 U.S. 1109, 122 S.Ct. 913, 151 L.Ed.2d 879 (2002),] however, the Federal Circuit no longer disregards the order of issuance. Instead ..., the current law now requires that the claim(s) of an earlier-filed but later-issued patent be held invalid if it is anticipated by, or is obvious in light of, the elaim(s) of a commonly-owned earlier-issued patent.” Id. In this case, Donaldson argues that the earlier-issued ’728 patent anticipates the later-issued ’456 patent, adding only an improved reset structure, and the ’456 patent is not “patentably distinct” from the ’728 patent, rendering the ’456 patent invalid under the rule of obviousness-type double patenting, as articulated in Eli Lilly. In response, EPC argues that, under the “one-way test” applied in Eli Lilly, claims 2 and 3 of the ’456 patent are “patentably distinct” from the claims of the ’728 patent, because those claims claim a “guiding means” that is neither claimed in the ’728 patent, nor obvious over the claims of the ’728 patent. Moreover, EPC argues that, in the circumstances presented here, the “two-way test,” not the “one-way test” should apply, allowing it to demonstrate that the earlier-issued ’728 patent is also patentably distinct from the later-issued ’456 patent, because claim 1 of the ’728 patent claims a novel reset structure that is not claimed in claim 1 of the ’456 patent. EPC contends that the Eli Lilly decision did not sweep away the two-way test, but instead held that it was inapplicable in the circumstances presented in that case. EPC contends, however, that the two-way test is applicable here, because the inventions were made at different times, and accordingly, different application dates with different specifications for the ’456 patent and the ’728 patent were necessary and proper, and EPC did not control or “orchestrate” the progress of the two patents through the PTO, or delay prosecution of the ’456 patent. Still more specifically, EPC contends that, during the “critical” period of “co-pendency” of the applications for the two patents, the PTO, not EPC, delayed the application for the ’456 patent by not responding to a continuation for over 21 months. In its reply brief, Donaldson argues that Eli Lilly, as well as earlier precedent, establish that the two-way test is only available in circumstances presenti