Palo Alto Networks, Inc. v. Finjan, Inc., 19-2151

Background

The ’154 patent (Finjan) claims a system to protect client computers from dynamically generated malicious content by replacing an original function with a substitute (first) function that sends the input to a remote security computer; the original (second) function is invoked only if the security computer indicates it is safe.
Independent claim 1 requires “content including a call to a first function,” i.e., a programmatic statement in the content that causes the first (substitute) function to provide a service.
Palo Alto challenged claims as obvious over Ross, which discloses hook functions that supersede original functions and cause hooked behavior, but does not explicitly show a programmatic call that names the hook.
The PTAB initially construed “a call to a first function,” found Ross did not disclose that limitation, and held claims 1–8, 10, and 11 not shown unpatentable; Palo Alto sought rehearing when a related IPR used slightly different language.
After this court’s SAS remand, the Board instituted review of dependent claims 9 and 12, adopted its prior findings, and on remand again held Palo Alto failed to show claims unpatentable; the Board relied on expert testimony and distinguished a mere invocation from an explicit programmatic call.
The Federal Circuit affirmed: it held the Board did not add an extra limitation, its application of the construction was supported by substantial evidence, and other appellate arguments (including an Arthrex challenge) were forfeited or without merit.

Issues

Issue	Palo Alto's Argument	Finjan's Argument	Held
Whether the Board added a limitation (direct naming) when applying its construction of “a call to a first function”	Board’s original language implied the first function must be explicitly called; after adopting the IPR2015-01979 wording, the Board should have revisited invalidity analysis because new wording is broader	The Board consistently treated a “call” as a programmatic statement that causes the function to provide a service and distinguished that from mere invocation; Palo Alto requested the same construction	The Board did not add a direct-naming limitation; its construction and application were consistent and lawful
Whether Ross discloses “a call to a first function” as claimed	Ross’s hook functions and pseudocode effectuate calls to hooks and thus satisfy the claim	Ross teaches calls to the original (second) function that indirectly invoke hooks but does not disclose an explicit programmatic call to the hook (first) function	Substantial evidence supports the Board’s finding Ross lacks an explicit call to the first function; Ross does not disclose the claimed element
Whether Board erred by not reopening invalidity analysis after modifying the claim construction on rehearing	Because the rehearing construction (from IPR2015-01979) was broader, the Board should have reexamined its obviousness findings under that construction	Board adopted the consistent construction and explained the modification did not expand scope to include invocations of different functions; no reanalysis required	The Board permissibly applied the construction; no remand required for reanalysis
Constitutional/appointment challenge (Arthrex) and other procedural arguments	Palo Alto argued the Board panel was unconstitutionally appointed (citing Arthrex), seeking vacatur/remand	USPTO/Finjan noted Palo Alto forfeited such an Arthrex challenge by not timely raising it before the Board; other procedural arguments unsupported	The court rejected/treated the Arthrex argument as forfeited and found the related procedural arguments without merit

Key Cases Cited

Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (claim-construction precedent)
SAS Institute Inc. v. Iancu, 138 S. Ct. 1348 (2018) (instituting review must cover all challenged claims)
Arthrex, Inc. v. Smith & Nephew, Inc., 941 F.3d 1320 (Fed. Cir. 2019) (separation-of-powers/appointment issues for PTAB judges)
In re Baxter Int’l, 678 F.3d 1357 (Fed. Cir. 2012) (obviousness is a legal conclusion based on factual findings)
Graham v. John Deere Co., 383 U.S. 1 (1966) (framework for obviousness analysis)
Immunex Corp. v. Sanofi-Aventis U.S. LLC, 977 F.3d 1212 (Fed. Cir. 2020) (standard of review for Board claim construction)
Ciena Corp. v. Oyster Optics, LLC, 958 F.3d 1157 (Fed. Cir. 2020) (forfeiture of Arthrex challenge in certain circumstances)
Respironics, Inc. v. Zoll Med. Corp., [citation="656 F. App'x 531"] (Fed. Cir. 2016) (challenging Board’s application of a claim construction)
AC Tech. S.A. v. Amazon.com, Inc., 912 F.3d 1358 (Fed. Cir. 2019) (applicable claim-construction standard for pre-November 2018 IPRs)
In re Abbott Diabetes Care Inc., 696 F.3d 1142 (Fed. Cir. 2012) (precedent on Board claim-construction application)
Intervet Inc. v. Merial Ltd., 617 F.3d 1282 (Fed. Cir. 2010) (review of Board’s application of claim construction)