Expert Testimony Must Be Tethered to Supporting Evidence

| Christie Matthaei

Before Reyna, Hughes, and Stoll. Appeal from the Patent Trial and Appeal Board.


Summary: Findings of fact at the PTAB must be supported by substantial evidence, and conclusory expert testimony, without supporting evidence, is not substantial evidence.

TQ Delta, LLC (“TQ Delta”) filed suit against several telecommunication companies, including Cisco Systems, Inc. (“Cisco”). In response, Cisco filed two IPR petitions challenging all claims of both patents. Every ground of the petitions included the combination of prior art references Shively and/or Stopler. The PTAB invalidated all claims of both patents and adopted Cisco’s position, which relied heavily on the testimony of Cisco’s expert. TQ Delta timely appealed to the Federal Circuit.

The Federal Circuit reversed the PTAB’s finding of obviousness and held that the PTAB’s fact-finding was based on conclusory testimony unsupported by substantial evidence. The Court determined that Cisco’s expert only offered unsupported and conclusory statements which failed to provide “meaningful explanation for why one of ordinary skill in the art would be motivated to combine.” Further, the Federal Circuit found that Cisco’s expert’s statements were not tethered to any supporting or contemporaneous evidence besides the description of the invention in the patents-in-suit. For those reasons, the Federal Circuit reversed the PTAB’s decision.

Editor: Paul Stewart