Mark Perry, Gibson, Dunn & Crutcher partner Mark Perry, Gibson, Dunn & Crutcher partner

Apple has added Gibson, Dunn & Crutcher to its legal team in a messy patent fight where the company alleges improper ex parte contact between its opponent and key officials at the U.S. Patent and Trademark Office tainted the outcome of an administrative patent trial.

The iPhone maker is asking the Patent Trial and Appeal Board (PTAB) to reverse a final decision in favor of Voip-Pal.com, and instead declare the patents related to voice-over-internet protocol invalid as a sanction. If the PTAB isn't willing to take that extraordinary step, then Gibson partners Mark Perry and Brian Buroker will likely be leading the charge for Apple to the Federal Circuit. Because of the unusual posture of the case, Apple was forced to preserve its appellate rights Thursday.

Perry, a Washington, D.C.-based partner who leads Gibson's appellate and constitutional law practice, is a go-to lawyer for Apple in IP appeals. His ties to the company are looking even stronger with the entrance of Apple's new GC Katherine Adams, who clerked for Supreme Court Justice Sandra Day O'Connor during the 1993-94 term, the same year as Perry.

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Erise IP partners Adam Seitz and Eric Buresh represent Apple before the PTAB.

They allege that Voip-Pal.Com, which is seeking $2.8 billion in federal court patent litigation against Apple, secretly lobbied PTAB Chief Judge David Ruschke and the administrative judges hearing Apple's validity challenge. Former Voip-Pal CEO Thomas Sawyer wrote a series of letters accusing the PTAB judges hearing its case of conflicts of interest, and complaining generally of unfairness to patent owners. Three new judges were substituted into the case a month later and ultimately ruled against Apple, disagreeing with the original panel on a key issue.

Voip-Pal initially claimed that Sawyer was nothing more than a concerned shareholder. More recently the company admitted that Sawyer conferred with Voip-Pal management and unspecified attorneys about the letters, but argues they were within PTAB rules.

Voip-Pal.com is represented by Knobbe Martens and Kevin Malek of Malek Moss.

Read more:

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