Precedential Federal Circuit Decision Serves as a Cautionary Reminder of Prosecution History Estoppel
New York, NY, July 22, 2025
The Federal Circuit issued a precedential decision in Colibri Heart Valve LLC v. Medtronic CoreValve, LLC, No. 2023-2153 (Fed. Cir. July 18, 2025) that expansively applies prosecution history estoppel to limit application of the doctrine of equivalents.
The patent at issue (U.S. Patent No 8,900,294) is directed to methods of partial deployment of artificial heart valves. Colibri initially pursued an independent claim that recited partially deploying the valve by “pushing” a stent and another independent claim that recited partially deploying the valve by “retracting” a sheath that surrounds a stent. During prosecution, the latter was rejected for lack of written description and subsequently cancelled.
In district court, Colibri accused Medtronic of infringing the “pushing” claim under the doctrine of equivalents. Medtronic contended that its product did not infringe because it employed retracting, not pushing, and that prosecution history estoppel precluded Colibri’s use of the doctrine of equivalents. Colibri argued that it could use the doctrine of equivalents because the cancelled claim “did not require pushing the inner member—only retracting the moveable sheath—whereas Medtronic’s [accused devices] require both pushing and retracting.” Slip op. at 17. The district court agreed with Colibri and therefore denied Medtronic’s motion for summary judgment of noninfringement and the case proceeded to trial. After trial, the jury found Medtronic liable for induced infringement of the “pushing” claim under the doctrine of equivalents and awarded Colibri damages of $106 million.
In reversing the jury verdict, the Federal Circuit reasoned that the underlying prosecution history estopped Colibri from asserting the doctrine of equivalents to find infringement. As the Federal Circuit explained: “Narrowing is a prerequisite to prosecution history estoppel … But the required narrowing is not a purely formal matter of altering a single claim’s terms. It can exist, and we conclude here does exist, as a substantive matter based on cancelling a closely related claim involving such intertwined terminology that cancelling one claim necessarily communicated that the scope of the other claim had narrowed.” Slip op. at 19. The Federal Circuit found that such intertwining between pushing and retracting existed in this case based on “Colibri’s assertions before this court [the Federal Circuit] and the district court, coupled with the surrounding claim language.” Id. at 18.
The Federal Circuit, in reaching its conclusion, quoted Festo’s statement that “[e]stoppel is a ‘rule of patent construction’ that ensures that claims are interpreted by reference to those ‘that have been cancelled or rejected,’” and noted that the principle of estoppel “by its terms does not limit estoppel to situations in which the issued, asserted claim itself was amended.” Slip op. at 20. The decision also quotes Schriber-Schroth Co. v. Cleveland Trust Co., 311 U.S. 211, 218 (1940): “Where the patentee … has, by amendment, cancelled or surrendered claims, those which are allowed are to be read in the light of those abandoned and an abandoned claim cannot be revived and restored to the patent by reading it by construction into the claims which are allowed.” Slip op. at 21 n.3. Thus, the Federal Circuit’s reasoning reiterates well-established principles of prosecution history estoppel.
Notably, when canceling the “retracting” independent claim, Colibri took steps to insulate against prosecution history estoppel by expressly reserving the right to pursue cancelled claims in a different application and even pointing to specific disclosure for written description support. However, such steps proved insufficient.
This decision serves as a reminder that prosecution history estoppel is not limited to claims that are amended and may arise from claims that are cancelled. Furthermore, this decision is a reminder that attempts during prosecution to insulate against the effects of prosecution history estoppel by including language regarding alternate reasons for cancellations or amendments (e.g., solely to expedite allowance) may prove futile.