CAFC Affirms PTAB Finding that Glucose Sensor Patent Claims are Obvious

The U.S. Court of Appeals for the Federal Circuit (CAFC) today affirmed a Patent Trial and Appeal Board (PTAB) ruling that claims of DexCom, Inc.’s patent for implantable glucose sensors were unpatentable as obvious. The CAFC opinion was authored by Judge Nina Y. Wang of the United States District Court for the District of Colorado, sitting by designation.

Abbott Diabetes Care, Inc. brought the inter partes review (IPR) against claims 1–3 and 11–13 of DexCom’s U.S. Patent No. 10,702,193 (the CAFC opinion mistakenly references U.S. Patent No. 10,792,193). DexCom sued Abbott, alleging infringement of the ’193 patent and Abbott subsequently petitioned for IPR, alleging the challenged claims would have been obvious over U.S. Patent Application Publication No. 2005/0215871 (“Feldman”). The Feldman application discloses blood glucose sensors that “may be placed internally, transcutaneously, or externally, relative to a body.” Abbott’s expert argued a person skilled in the art would have understood from the figures in Feldman that stacked layers with “non-conductive layers between the electrode layers to prevent a short circuit between the electrodes” as outlined in the challenged claims of DexCom’s patent were an obvious solution. The PTAB instituted the IPR And agreed with Abbott’s expert testimony that “’Feldman’s Figures 4A–B would have been understood and interpreted by a person of ordinary skill in the art as encompassing’ the claimed five-layer arrangement of stacked electrodes and non-conductive layers.”

DexCom argued on appeal that the Board did not consider that Feldman allows for other arrangements and thus did not rely on substantial evidence. But the CAFC said this was a misreading. “The Board acknowledged DexCom’s alternative interpretations of Feldman, but determined the existence of alternatives did not refute Dr. Smith’s testimony that a skilled artisan would read Feldman to encompass a sensor with stacked electrodes separated by non-conductive layers,” wrote the CAFC.

DexCom further argued that the Board was inconsistent in its statement that Feldman “encompasses” the claimed arrangement while simultaneously acknowledging at times that Feldman does not actually “disclose” any such arrangement. An obvious but undisclosed arrangement would require modification and DexCom argued the Board therefore failed to provide DexCom the notice and opportunity required under the Administrative Procedure Act (APA) to respond to that argument. But Abbott argued the Board’s decision did not rely on modification of Feldman to achieve the claimed arrangement and the CAFC agreed.

Pointing to the “expansive and flexible approach” to obviousness taught by KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 415, 418 (2007), the CAFC said the Board’s reasoning was correct:

“Consistent with this standard, the Board focused its inquiry on what Feldman would teach or suggest to a person of ordinary skill in the art, rather than limiting itself to what Feldman literally says or shows.”

The court also found that the PTAB used the word “alternative” in its discussion of Feldman “to refer to the alternative interpretations of what is shown in Feldman’s Figures 4A and 4B, not alternative arrangements based on modifying Feldman.” Thus, the opinion said in a footnote that the court did not need to address DexCom’s argument about the Board’s APA violation.

Finally, the CAFC agreed with Abbott that DexCom waived its argument that only the filed version of Feldman should have been considered as prior art, not the published version. According to DexCom, the figures differed significantly between the filed and published versions, but Abbott argued that this argument was waived because DexCom didn’t raise it in its post-institution response. “[I]n its post-institution response, DexCom argued only that the ‘Feldman publication . . . itself is insufficient evidence of the contents of the Feldman application as filed,’” wrote the CAFC. “That is insufficient to preserve the argument DexCom now presents regarding the difference between the filed and published versions of Figure 4A in Feldman.”

Abbott withdrew from the appeal before oral argument, so Acting Director of the U.S. Patent and Trademark Office, Coke Morgan Stewart, intervened, relying on Abbott’s brief. The CAFC ultimately affirmed the PTAB’s decision that DexCom’s patent claims were unpatentable as obvious.

Image Source: Deposit Photos
Author: sharafmaksumov
Image ID: 229492118