by Dennis Crouch
The Federal Circuit’s new decision in Medtronic v. Teleflex delves into the old pre-AIA law of inventorship and prior art. It also provides an important appellate procedure lesson with the court finding the appellant waived a key argument.
Teleflex’s U.S. Patent No. RE46,116 claims methods for using a special extension for its guide catheter. Medtronic filed a pair of IPR petitions, asking the USPTO to cancel the claims. Although the PTAB granted the petitions, it eventually sided with the patentee — agreeing that one of the asserted references did not qualify as prior art. On appeal, the Federal Circuit has affirmed.
The basic question is whether Itou (7,736,355) qualifies as prior art against Teleflex’s patent (RE46,116). The Itou application was filed about nine-months before the Teleflex application.
Under the AIA Teleflex would clearly lose. Itou was filed first and eventually published and therefore qualifies as prior art under AIA 102(a)(2). And, the AIA limited 1-year grace period under 102(b)(2) would not apply since Teleflex did not first disclose the invention. But, these applications are all pre-AIA.
In this situation, Medtronic wants Itou to qualify as prior art as of its application filing date. That means that we apply pre-AIA 102(e). 35 U.S.C. 102(e) provided that a person shall not be entitled to a patent if the claimed invention was described in a patent granted on an application for patent by another filed in the United States before the invention by the applicant for patent. Thus, Itou is prior art so long as it was filed prior to the Teleflex invention date.
Proving Invention Date. Establishing invention date requires determining when the inventor both conceived of the complete invention and then reduced it to practice. Conception is typically seen as the most important aspect of invention, but invention is not complete until it is reduced to practice. Conception occurs when an inventor forms a definite and permanent idea of the complete and operative invention in their mind. This is the critical inception of the invention. However, conception alone is not enough – the inventor must also reduce the invention to practice. This can occur either by actually building and testing the invention to show it works for its intended purpose (actual reduction to practice). But, in patent law we also observe the legal fiction that filing a patent application describing the invention in sufficient detail to enable a person skilled in the art to make and use it will also qualify (constructive reduction to practice).
When proving a prior invention date, the law allows inventors to claim all the way back to their provable date of conception, so long as they also show reasonable and continuous diligence by the inventor to reduce the invention to practice. Thus, if the inventor conceived the invention but then set it aside for a long period before filing a patent application or resuming diligent efforts to reduce it to practice, this can negate the prior invention date. Once the invention is reduced to practice, diligence is no longer required, but the inventor must be careful not to unduly delay in filing for patent protection because it could create abandonment, estoppel, or laches issues.
In this case, the PTAB agreed with Teleflex that Itou was not prior art, finding that the invention was both actually and constructively reduced to practice before Itou’s filing. On appeal, the Federal Circuit affirmed on the grounds of constructive reduction to practice, declining to reach the issue of actual reduction to practice. Constructive reduction to practice requires (1) conception prior to the filing date of the asserted reference, and (2) reasonably continuous diligence from just before the reference’s filing until the priority application.
Here, Teleflex provided dated technical documents about the “GuideLiner” product it was developing sufficient to prove diligence and submitted declarations and other supporting evidence showing ongoing development of the invention through the filing date of the patent application. These included records of prototypes, emails, testic documents, manufacturing prep, etc.
On appeal, Medtronic argued that the PTAB erred in finding that Teleflex established an actual reduction to practice before Itou’s filing date. Specifically, Medtronic asserted that the plain language of Teleflex’s claims requires in vivo testing, as the claims recite steps like “advancing a distal end of a guide catheter . . . through a main blood vessel to an ostium of a coronary artery.” According to Medtronic, Teleflex’s bench testing in an anatomical model was insufficient to meet this limitation and demonstrate actual reduction to practice. In response, Teleflex contended that actual reduction to practice allows some flexibility rather than rigidly requiring that every claim limitation be performed exactly as stated. Teleflex pointed to cases like In Re Spiller finding reduction to practice despite variations from the explicit claim language. However, the Federal Circuit panel questioned whether Spiller actually supports such flexibility, and whether the Board properly construed the precedent it relied on.
Ultimately, the Federal Circuit declined to decide the issue of actual reduction to practice, affirming solely on the grounds of constructive reduction to practice since Medtronic had seemingly waived its diligence arguments on appeal through improper incorporation by reference.
Incorporation by Reference Doesn’t Work: For anyone appealing to the Federal Circuit, the waiver aspect of this case will be the most important part. Appellants get 14,000 words in their appeal brief. Although that word length is quite a lot — it gets eaten up pretty quickly and appellants are regularly cutting arguments that they feel could be winners. Here, Medtronic attempted to incorporate 20 pages of briefing from another case by reference that detailed its argument on lack-of-diligence. The brief itself only included a cursory statement that if the Federal Circuit vacated the diligence finding in the parallel case, it should also vacate and remand on diligence here. But, Medtronic did not substantively argue against the PTAB’s diligence analysis in the brief proper. During oral arguments, Judge Chen offered the following remarks:
We have a 14,000 word count limit to our briefing. You’re at 13,979 and on page 41 you want to incorporate 20 pages of briefing from a separate appeal, which would obviously blow right through the 14,000 word count. So I’m trying to figure out what to do here. We’ve got 14,000 word count limit that’s being blown through. And likewise, we have a pretty strong precedent that says you’re not allowed to incorporate by reference arguments made in other documents into your briefing. So I don’t know if we can read this as a permissible incorporation by reference.
In the decision, the court concluded that the 14,000 word count limit for principal briefs under Federal Circuit Rule 32(a) along with prior precedent prohibits incorporation by reference to ensure parties fully develop their arguments within the allotted word limits. Despite Medtronic asserting the diligence issue was fully briefed in the other case, the Federal Circuit held Medtronic waived any challenges to the PTAB’s diligence determination and affirmed on the basis of Teleflex’s constructive reduction to practice. According to the court, Medtronic made a strategic decision (a bet) regarding how to allocate its words, and could not undo that choice by asking the court to consider extra-record briefing (without a successful motion to extend the word count). Thus, while Medtronic contested the finding of diligence before the PTAB, the Federal Circuit found this challenge waived on appeal due to inadequate briefing.
Affirmed.