Prosecution history estoppel may narrow the scope of a claim that was unamended during prosecution, if another closely related claim is amended or cancelled during prosecution.
Background
U.S. Patent No. 8,900,294 (the '294 patent) owned by Colibri Heart Valve LLC, claims a method for implanting an artificial heart valve. Colibri sued Medtronic CoreValve, LLC, a manufacturer of replacement heart valves, for infringement of the '294 patent in the U.S. District Court for the Central District of California—alleging that Medtronic was inducing surgeons to perform the claimed method of the '294 patent with Medtronic's products.
Initially, the '294 patent included two independent claims reciting the opportunity-for-do-over method of partial deployment: one claimed pushing out the valve from an outer sheath of the delivery apparatus, and the other claimed retracting the outer sheath to expose the valve. However, during prosecution, the examiner rejected the latter claim for lack of written description. In response, Colibri cancelled the rejected claim. The patent ultimately issued with an independent claim reciting partial deployment by pushing, and no claims expressly reciting partial deployment by retracting. The relevant limitation that was recited in the cancelled claim was "after the advancing step, partially deploying the replacement heart valve device within the patient by retracting the moveable sheath to expose a portion of the replacement heart valve device." '294 Patent, Cancelled Claim 39 (emphasis added). As a result, only a limitation reciting pushing out the valve remained, "after the advancing step, partially deploying a distal portion of the replacement heart valve device within the patient by pushing out the pusher member from the moveable sheath to expose the distal portion of the replacement heart valve device." '294 Patent at Claim 1 (emphasis added).
In the district court, Colibri only asserted induced infringement against Medtronic. Colibri Heart Valve LLC v. Medtronic CoreValve, LLC, 23-2153, 9 (Fed. Cir. 2025). A special master resolved a claim construction dispute between the parties, adopting Medtronic's construction that "pushing out the pusher member from the moveable sheath" meant "pressing against the pusher member with a force that moves the pusher member out of the moveable sheath." Id. at 9-10. The district court adopted the special master's recommended claim construction.
After claim construction both parties moved for partial summary judgment: Colibri for no invalidity, and Medtronic for invalidity and noninfringement. In its motion, Medtronic argued that prosecution history estoppel (i.e., the cancellation of claim 39) barred Colibri from asserting that under the doctrine of equivalents partial deployment and recovery of the valve is performed by retracting the sheath. Colibri, 23-2153 at 10. The district court adopted the special master's recommendation that cancelled claim 39 and retained claim 34 (issued claim 1) were separate and distinct. Id. at 11-12. Additionally, the special master distinguished Colibri's asserted equivalent as "not merely retraction" but instead "a combination of pushing and retracting, so the asserted equivalent . . . differ[ed] from what was set forth in the cancelled claim." Id. at 12. Accordingly, the district court denied Medtronic's motion for summary judgment.
During trial Medtronic filed two motions for JMOL seeking, as relevant here, judgment of no equivalents infringement on the ground of prosecution estoppel. Colibri, 23-2153 at 12. The district court did not rule on the motions. The jury ultimately found that Medtronic had induced infringement of claims 1-3 of the '294 patent and that Medtronic had not proved those claims were invalid, and as result awarded more than $106 million in damages to Colibri. Colibri, 23-2153 at 13. After the verdict, Medtronic renewed its JMOL. In denying Medtronic's motions, the district court rejected Medtronic's prosecution history estoppel argument "for the same reasons set forth by the Court during summary judgment proceedings." Id. at 13. Medtronic appealed, arguing among other things, that the district court erred in denying JMOL of noninfringement.
Issue(s)
- Did the district court err in denying Medtronic's request for judgment as a matter of law and rejecting Medtronic's prosecution history estoppel arguments that were based on a canceled claim?
Holding
- Yes. Medtronic was entitled to judgment as a matter of law of noninfringement of the '294 patent because prosecution history estoppel narrowed the scope of an asserted claim to exclude an asserted equivalent that was recited in another claim that was cancelled during prosecution.
Reasoning
While Medtronic's appeal challenged four rulings of the district court: (1) denial of JMOL of invalidity, (2) denial of JMOL of noninfringement, (3) denial of JMOL of no active inducement, and (4) denial of Medtronic's motion for a new trial on damages, it was undisputed that if the denial of JMOL of noninfringement were reversed, the Federal Circuit would not need to reach Medtronic's other challenges. Colibri, 23-2153 at 13.
The Federal Circuit applied the Ninth Circuit's de novo standard for reviewing the district court's JMOL decision. Colibri, 23-2153 at 13 (citing TEK Global, S.R.L. v. Sealant Systems International, Inc., 920 F.3d 777, 783 (Fed. Cir. 2019). The Federal Circuit noted that the JMOL standard itself, which regards fact issues, requires deference to the factfinder, i.e., JMOL is not to be granted unless "the evidence, construed in the light most favorable to the nonmoving party, permits only one reasonable conclusion, and that conclusion is contrary to the jury's verdict." Id. at 13 (citing TVIIM, LLC v. McAfee, Inc., 851 F.3d 1356, 1362 (Fed. Cir. 2017)). However, prosecution estoppel, is not a matter of fact but instead a matter of law, and is decided de novo on appeal according to Federal Circuit law. Id. at 13 (citing Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359, 1367-68 (Fed. Cir. 2003)(en banc)). Applying the law to Medtronic's appeal, while Medtronic asserted multiple grounds for challenging the district court's denial of JMOL determination, the Federal Circuit focused only on the prosecution history estoppel argument for noninfringement, which, if reversed, would moot the other grounds.
Colibri's Argument that Medtronic's Prosecution History Estoppel Argument was Waived
Colibri asserted that based on a pre-trial statement, Medtronic waived a prosecution history estoppel argument in by stating "Medtronic is not pursuing the Fifth Affirmative Defense of Prosecution History Estoppel." Colibri, 23-2153 at 14-15. This statement was made in accordance with a local rule of the Central District of California, which requires that the parties "identify any pleaded claims or affirmative defenses which have been abandoned." L.R.16-4.6. For three reasons the Federal Circuit held that Medtronic had not waived its JMOL argument based on prosecution history estoppel. See id. at 15-16.
First, while Medtronic's statement was poorly worded, it could reasonably be understood as Medtronic merely stating it would not repeat at trial, to the jury, an argument that was denied at summary judgment and that involved only a question of law on which no facts needed to be proved at trial. Colibri, 23-2153at 15. The Federal Circuit also acknowledged that Medtronic's statement included that the contentions made were "based on Medtronic's current understanding of the parties' claims in light of the Technical Special Master's Reports and Recommendations on Summary Judgment . . . . [and do] not constitute a waiver or concession of any aspect of Medtronic's objections or arguments made in connection with those orders, [nor] does it constitute a waiver of Medtronic's right to appeal the same." Id. Medtronic also made a similar disclaimer in its trial brief.
Second, when Medtronic made its motion for JMOL, it explicitly made its prosecution estoppel argument. In response, instead of arguing Medtronic had abandoned the argument, Colibri urged the district court to reject the argument solely based on the merits. As a result, Colibri forfeited the waiver argument "by addressing the claim on the merits without also making a waiver argument." Colibri, 23-2153at 15 (quoting Norwood v. Vance, 591 F.3d 1062, 1068 (9th Cir. 2010)).
Third, Colibri asserted the waiver defense for the first time in response to Medtronic's renewed JMOL motion despite having the opportunity to assert the argument in response to the original JMOL motion. Additionally, even when it asserted the argument, Colibri failed to establish any prejudice resulting from the pretrial statement followed by the raising of the issue of law in connection with JMOL. The district court disagreed with Colibri's waiver contention, and instead directly addressed the motion on the merits. The Federal Circuit also declined to find that Medtronic had waived its prosecution history estoppel argument.
The Merits of Medtronic's Prosecution History Estoppel Argument
Medtronic argued that the district court erred in concluding that Colibri's asserted equivalent was distinct and separate from what was recited in cancelled claim 39 and that Colibri's cancellation of claim 39 was not a narrowing amendment. Colibri, 23-2153 at 16.
In addressing this argument the Federal Circuit began with the district court's conclusion that the asserted equivalent differs distinctly from what was recited in cancelled claim 39. Colibri, 23-2153 at 17. Colibri argued that claim 39 did not require pushing the inner member (only retracting the movable sheath), and Medtronic's accused infringing devices require both pushing and retracting. The district court agreed with Colibri holding that Colibri's "asserted equivalent is not merely retraction" and the asserted equivalent differs from what was set forth in the cancelled claim. Id. at 17.
Colibri's theory of equivalents hinged on "simple physics," namely that a relevant artisan would understand that pushing necessarily accompanies retracting, i.e., "there's absolutely no way to deploy the replacement heart valve without applying opposing forces, [a pushing force and a retracting force]." Colibri, 23-2153 at 17-18. Additionally, claim language in both retained claim 34 (issued claim 1) and cancelled claim 39 further indicate that the relevant artisan would know that pushing necessarily accompanies retraction. Id. at 18. As a result the Federal Circuit held that the special master and the district court were incorrect that Colibri's asserted equivalent distinctly differed from what was set forth in claim 39 such that the substance dropped when cancelling claim 39 is quite separate from the substance of retained claim 34 (issued claim 1).
Medtronic also argued that Colibri's cancelling of claim 39 in favor of pursuing limitations that already appeared in retained claim 34 (issued claim 1) was a narrowing amendment giving rise to prosecution history estoppel. Colibri, 23-2153 at 19-25. The Federal Circuit acknowledged that for prosecution history estoppel to apply there must be a narrowing of the claims. However, the Federal Circuit held that narrowing must not necessarily be a "purely formal matter of altering a single claim's terms," instead narrowing can exist (as it did here) as a substantive matter, where cancellation of a closely related claim "involving such intertwined terminology that cancelling one claim necessarily communicated that the scope of the other claim was narrowed." Id. at 19.
The Federal Circuit reiterated its reasoning that the cancellation of claim 39 bears on what can be covered under the doctrine of equivalents by claim 1 because a relevant artisan would understand the "close basic-physics" relationship between of the cancelled and retained claims. Colibri, 23-2153 at 19. Accordingly, the Federal Circuit viewed the district court's rationale that cancelled claim 39 and retained claim 34 (issued claim 1) were separate and distinct, as reliant on an "entirely formal point" that requires a formal claim relationship between the cancelled and allowed claim (e.g., independent and dependent). Thus, for the district court's reasoning to justify denying estoppel, formalities must be determinative, which the Federal Circuit held were not.
The Federal Circuit pointed to governing law that "precludes making formalities determinative, to the exclusion of substantive relationships that would be understood by relevant readers." Colibri, 23-2153 at 20. First, the Federal Circuit noted that "estoppel" is a "rule of patent construction" that requires claims be "interpreted by reference to those claims that have been cancelled or rejected." Id. at 20 (quoting Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 733 (2002)). Furthermore, this principle does not limit estoppel only to situations in which the issued, asserted claim itself was amended, instead the inquiry is the scope of the claims of the patent as a whole, pre- and post-amendment. Id. at 20-21.
Additionally, the Federal Circuit noted that a formalistic approach to the narrowing inquiry was rejected in Honeywell International Inc. v. Hamilton Sundstrand Corp., 370 F.3d 1131, 1141-44 (Fed. Cir. 2004) (en banc). In that case, Honeywell argued that rewriting a dependent claim into independent form does not give rise to the presumption of prosecution estoppel because "the scope of the rewritten claims themselves has not been narrowed." Colibri, 23-2153 at 22 (quoting Honeywell, 170 F.3d at 1141). However, the Federal Circuit rejected that argument, based on the Supreme Court's decision in Festo. Specifically, a purely formalistic approach "conflates the patentee's reason for making the amendment with the impact the amendment has on the subject matter." Id. at 22 (Honeywell 1141-42 & n.7).
The Federal Circuit also cited further case law to support the principle that cancellation of claims for reasons related to patentability in favor of claims with a narrower literal scope has the same presumptive effect on claim limitations as amending the claims directly. Colibri, 23-2153 at 23-24. In other words, when evaluating prosecution history estoppel, claims are not addressed in isolation, considering only whether the asserted claim was amended. Id. at 23. Instead, cancellation of a prior, broader independent claim may give rise to prosecution history estoppel in relation to a narrower claim, depending on the relationship between the scopes of those claims. Id. at 23-24. For all of these reasons the Federal Circuit rejected Colibri's contention that claim 1 itself needed to be amended for prosecution estoppel to apply.
Conclusion
The Federal Circuit determined that Medtronic was entitled to judgment as a matter of law of noninfringement of the '294 patent, and reversed the district court's denial of Medtronic's motion for JMOL. Accordingly, the grant of JMOL on noninfringement mooted the remaining aspects of the appeal (invalidity, remaining noninfringement arguments, and damages).
Apart from the highlighting the importance of procedural takeaways, mainly addressing arguments believed to be waived early, often, and explicitly; this case was also instructive to patent practitioners particularly. Both in prosecution and when reviewing prosecution history, consideration should be taken when in regard to claim amendments when considering prosecution history estoppel. Specifically, consideration should be taken to how the cancellation of independent claims may affect the scope of claims that have not been amended.
