In this week’s Case of Week, the Federal Circuit affirmed inter partes review decisions upholding as patentable Teleflex’s challenged patent claims directed to a method for use of a guide extension catheter in arteries.  This case is the latest development in the Medtronic and Teleflex saga—our write-up of a previous precedential opinion in the same matter is available here.  At that stage, the Board had found that Teleflex’s evidence supporting reduction to practice of its claimed invention was adequate to antedate a prior art reference (“Itou”) because Teleflex demonstrated that the invention prototype was able to perform its intended purpose based on a substantial evidence standard.

On remand of its two petitions for inter partes review, Medtronic again argued that Teleflex’s ’116 patent claims were obvious over Itou.  Teleflex again argued that Itou did not qualify as prior art under pre-AIA law because the claimed invention was: (1) conceived prior to Itou’s filing date and (2) was either (a) actually reduced to practice before the critical date or (b) diligently pursued until its constructive reduction to practice through its effective filing date.  There was no contention regarding the demonstration of conception, but Medtronic did contest Teleflex’s showing of reduction to practice.

The Board found: (1) that the ’116 patent’s claimed invention was conceived before Itou’s critical date, (2) that the claimed invention was actually reduced to practice before the critical date, and (3) that the patent owner diligently pursued work on the invention until its constructive reduction to practice through its effective filing date.  The Board here used the same analysis prescribed by the Federal Circuit in the earlier Medtronic case, supra.

However, one question unique to the present case was whether in vivo testing of the claimed method was required for a showing of actual reduction to practice.  The Board held that it was not because the claimed method could be demonstrated using a physical model replicating human arterial anatomy.

In reviewing the Board’s decision, the Federal Circuit noted that under pre-AIA law, a patent owner may antedate an asserted prior art patent based on a constructive reduction to practice by showing conception of the invention before the critical date and either actual reduction to practice or reasonably continuous diligence in reducing the invention to practice until its effective filing date.  See ATI Techs. v. Iancu, 920 F.3d 1362, 1369 (Fed. Cir. 2019); Tyco Healthcare Grp. v. Ethicon Endo-Suergery, Inc., 774 F.3d 968, 975 (Fed. Cir. 2014).  The Federal Circuit thus affirmed the Board’s finding of constructive reduction to practice without needing to reach to the issue of whether a lack of in vivo testing precluded a finding of actual reduction to practice.

Medtronic also attempted to argue that Teleflex did not exercise reasonably continuous diligence until the constructive reduction to practice of the claimed invention, but the Court found that argument to have been waived.  Medtronic asserted that it preserved an opportunity to argue against the diligence finding by referring to two sentences in Medtronic’s opening brief: “In addressing diligence, the Board simply adopted its earlier erroneous diligence analysis in IPR2020-00132.  Appx61-62.  Therefore, if this Court vacates the Board’s diligence holding in No. 21-2356, it should likewise vacate the Board’s decisions here.”  Since the Court did not vacate the Board’s decision in the referenced appeal, the Federal Circuit considered Medtronic’s diligence argument waived.  The Court also noted that Medtronic was not permitted to maintain its diligence argument through an improper incorporation by reference of its brief for the earlier Medtronic case.  Since Medtronic’s diligence argument here was based only on the improper incorporation by reference, and was not made within the word limit of Medtronic’s opening brief, the Federal Circuit maintained that Medtronic had waived its opportunity to argue against the Board’s diligence finding.

The opinion can be found here.

By Ann Bernert

This article summarizes aspects of the law and does not constitute legal advice. For legal advice for your situation, you should contact an attorney.