Federal Circuit Vacates PTAB Rejection of Catheter Patent Application Over Incorrect Claim Construction

The U.S. Court of Appeals for the Federal Circuit (CAFC) issued a decision today in In re Incept LLC, vacating and remanding a Patent Trial and Appeal Board (PTAB) decision that had affirmed an examiner’s rejection of a medical catheter patent application as obvious. Since the Board’s obviousness analysis relied on an incorrect construction of the claim term “flow barrier,” the CAFC declined to reach the underlying obviousness question and returned the case to the Board for further proceedings.

Incept LLC appealed the Board’s decision affirming an examiner’s rejection of claim 1 of U.S. Patent Application No. 16/886,099, titled “Anchoring Strain Relief Member,” as unpatentable under 35 U.S.C. Section 103. The application describes a medical catheter comprising a catheter shaft, a hub attached to the shaft’s proximal end, and an anchoring strain relief member positioned distal to the hub. The strain relief member includes a sealing portion made up of ridges, with claim 1 requiring each ridge to form a “flow barrier” between the catheter’s outer surface and the top of the ridge. The sealing portion also must have no more than about a 1.5 degree forward taper in the proximal to distal direction.

On July 1, 2024, the examiner rejected several claims of the application, including claim 1, as obvious over a single prior art reference identified in the opinion as Thomspon Smith. Incept challenged only the rejection of claim 1 on appeal. The examiner found that Thomspon Smith disclosed every limitation of claim 1 except the specific taper angle of the sealing portion, and acknowledged that the reference never said outright that its strain relief member had a forward taper, nor identified what degree of taper, if any, it possessed. The examiner nonetheless concluded that the dimensional difference did not create a patentable distinction, reasoning that Incept had attributed no special function to the claimed taper range. The examiner further construed the “flow barrier” limitation as permitting the barrier to sit anywhere between the catheter’s outer surface and the ridge top, and found that Thomspon Smith’s ridged strain relief member satisfied that limitation.

The Board reversed the examiner’s rejection of several other claims but affirmed the rejection of claim 1, agreeing that Thomspon Smith disclosed the claimed structure aside from the taper angle and that modifying the reference to meet the taper limitation would have been obvious. Incept requested rehearing, arguing that the Board had overlooked a dispute over the construction of “flow barrier” and that Thomspon Smith did not teach that limitation at all. The Board denied rehearing, adopting the examiner’s construction and stating that the claim “does not require sealing of the catheter outer surface to the ridges, but rather, recites the position of the flow barrier between the catheter and the top of the ridge.”

The CAFC reviews the Board’s claim construction de novo and its ultimate obviousness determination de novo as well, while reviewing underlying factual findings for substantial evidence. On appeal, Incept argued that the Board’s construction of “flow barrier” lacked support in the intrinsic evidence and that the examiner and Board failed to establish a prima facie case of obviousness. The court addressed only the claim construction argument, and agreed with Incept.

Moreover, the court explained that examiners and the Board are required to interpret claims as broadly as the specification will reasonably allow, though it has limits, since “the Board cannot construe the claims so broadly that its constructions are unreasonable under general claim construction principles.” The court also examined two dependent claims that the Director cited as evidence that Incept knew how to claim a fluid-tight seal when it wanted to, and found those claims more consistent with Incept’s construction than with the Board’s.

The court also rejected the Director’s argument that Incept’s construction improperly imported an unclaimed nested configuration into the claim. It explained that the specification’s description of a fluid-tight junction between the sealing portion and an elastomeric member did not depend on any particular configuration of use. The CAFC ultimately construed “flow barrier” to be “a solid surface that spans from the catheter outer surface to the top of the ridge along a circumference at the location of the ridge.”

Since the Board’s obviousness analysis had proceeded on the understanding that the only difference between the prior art and claim 1 involved relative dimensions, the CAFC found that the incorrect construction impaired the Board’s obviousness analysis. The court did not reach the merits of the obviousness rejection and instead remanded for the Board to evaluate patentability under the construction outlined in the opinion.

Ultimately, the CAFC vacated the Board’s decision affirming the rejection of claim 1 of the ‘099 application and remanded for further proceedings.