Background
Teleflex Life Sciences Ltd. owns patents covering guide extension catheters used in interventional cardiology procedures — specifically, the GuideLiner catheter. Guide extension catheters are hollow tubes that extend through a guide catheter to provide additional support and reach during coronary interventions. The key patent at issue, U.S. Patent No. 7,736,355 (the ‘116 patent), was originally developed by Vascular Solutions, Inc. and claimed methods for using a guide extension catheter in combination with a guide catheter.
Medtronic, Inc. launched its own competing guide extension catheter product — the Telescope — in 2019. Facing allegations of infringement, Medtronic filed two petitions for inter partes review (IPR) of the ‘116 patent before the Patent Trial and Appeal Board (PTAB), arguing that a prior art reference (the “Itou” reference) anticipated or rendered the claims obvious. The PTAB found in Teleflex’s favor, concluding that Itou was not prior art because Teleflex’s inventors had conceived the invention and diligently reduced it to practice before Itou’s critical date. Medtronic appealed both IPR decisions to the Federal Circuit.
The Court’s Holding
The Federal Circuit affirmed the PTAB across both appeals. The central dispute was whether Itou qualified as prior art to the challenged patent. To defeat Itou as prior art, Teleflex needed to show that its inventors had conceived the claimed invention and either actually or constructively reduced it to practice before Itou’s date, and that the inventors diligently pursued reduction to practice throughout the relevant period.
The parties had stipulated that conception occurred before the critical date, so the key issues were actual or constructive reduction to practice and diligence. The Federal Circuit found that Medtronic had waived its challenge to the PTAB’s diligence finding by inadequately raising it in its opening brief — a cautionary reminder that arguments not properly developed in opening briefs are forfeited on appeal. With conception uncontested and diligence waived, the prior art challenge collapsed. The court accordingly affirmed the PTAB’s determination that Itou did not qualify as prior art to the ‘116 patent, and that Medtronic had not proven the claims unpatentable.
Key Takeaways
- In IPR proceedings, a patent owner can defeat an asserted prior art reference by establishing prior conception and diligent reduction to practice — the classic antedating maneuver available under pre-AIA law for patents claiming pre-March 2013 priority dates.
- Arguments not adequately briefed in opening appellate briefs are waived — Medtronic lost its diligence challenge on this procedural ground alone.
- Medical device companies targeting competitors’ IPR-vulnerable patents must ensure their invalidity arguments are comprehensively developed at the Board level and preserved meticulously on appeal.
- The decision illustrates how IPR petitions against older medical device patents can fail when the patent owner successfully antedates the asserted prior art.
Why It Matters
The cardiovascular medical device sector is intensely competitive, with major companies frequently using IPR proceedings to challenge competitors’ patents on products they want to enter the market with. This case illustrates the limits of that strategy when a patent’s inventors can demonstrate priority over the asserted prior art. For medical device patent holders, the case underscores the value of maintaining thorough laboratory notebooks and invention records that can establish conception dates and document the diligent path from idea to working prototype.
The waiver holding also carries a broader lesson for appellate practice: arguments that are raised but not adequately developed — especially challenges to specific PTAB factual findings — will be treated as forfeited. Litigants appealing PTAB decisions to the Federal Circuit must ensure that every challenged finding is briefed with full argument, not merely referenced or incorporated by mention.