Affirming denial of a motion for a new trial, the US Court of Appeals for the Federal Circuit found that an accused infringer appropriately argued both non-infringement and invalidity, even though it used a form of the "practicing the prior art" argument. 01 Communique Lab., Inc. v. Citrix Systems, Inc., Case No. 17-1869 (Fed. Cir., Apr. 26, 2018) (Hughes, J).

Communique owns a patent relating to a method of allowing a remote computer to access a personal computer using the internet. The patent requires that the communication channel between the remote computer and the personal computer be created by a separate "location facility." In 2006, Communique accused Citrix's GoToMyPC connection service of infringing its patent. Citrix filed an inter partes re-examination asserting that certain prior art invalidated the patent's claims, including Citrix's prior art BuddyHelp connection service. The Patent Trial and Appeal Board upheld the validity of the asserted claims, and the case proceeded to trial in the district court.

At trial, the district court allowed Communique to use certain parts of the inter partes re-examination proceeding, but prohibited Communique from identifying Citrix as the challenger because the prejudice to Citrix outweighed any probative value. Citrix argued that its GoToMyPC service did not infringe the claims because the communication channel in that service is created by the remote computer and personal computer, not a separate location facility. It also argued that if the asserted patents were read broadly enough to cover GoToMyPC, then they would be invalid, because the BuddyHelp service used the same process to establish the communication channel. The jury found that the asserted claims were valid, but that GoToMyPC did not infringe. The district court denied Communique's request for a new trial. Communique appealed.

On appeal, Communique argued that Citrix improperly engaged in a "practicing the prior art" defense during which it did not make the required comparison between the GoToMyPC service and the asserted claims and instead compared the GoToMyPC service to the prior art BuddyHelp service. Communique argued that it was prejudiced by this improper comparison, which warranted a new trial.

The Federal Circuit disagreed. While the Court acknowledged that there is no "practicing the prior art" defense to literal infringement, it found that Citrix's litigation strategy was appropriate. First, the Court found that Citrix compared the GoToMyPC service to the asserted claims and presented expert testimony and evidence that the "location facility" limitation was missing from GoToMyPC. The Court found this sufficient to support the jury non-infringement finding. The Court then noted that the comparison between GoToMyPC and BuddyHelp was performed during the invalidity case where Citrix argued that if GoToMyPC infringed the patent, then BuddyHelp must invalidate. The Court found no problem with this argument, noting that a comparison between the accused product and the prior art does not automatically cause prejudice mandating a new trial. Instead, the Court noted that there may be certain situations where such a comparison is warranted. The Court thus affirmed the district court's decision.

"Practicing the Prior Art" Argument Acceptable If Done Correctly

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