Jennifer Chen, left, and John Fuisz, right, of Vinson & Elkins in Washington, D.C.
Jennifer Chen, left, and John Fuisz, right, of Vinson & Elkins in Washington, D.C. (Courtesy photos)

The intellectual property attorney who went head-to-head with the embattled blood-testing startup Theranos Inc. over trade secrets is back in Big Law.

John Fuisz and his boutique co-owner Jennifer Chen have joined Vinson & Elkins in Washington, D.C., as partners, the firm announced Monday. Fuisz worked at McDermott Will & Emery until 2010, when he started his own D.C. firm. It combined with Chen’s firm and took the name Fuisz Chen last year.

Fuisz and his family became embroiled in litigation with Theranos after the company’s founder, Elizabeth Holmes, accused him in a 2011 federal lawsuit of stealing trade secrets. Fuisz was a board member of a pharmaceutical company owned by his brother and father in the 1990s, and McDermott’s IP group had represented Theranos.

An amended version of the dispute between Theranos and the Fuiszes, which eventually dropped John Fuisz as a defendant, went before a jury in March 2014. The Fuiszes denied the claims, and the parties settled midway through trial. At the time, Fuisz called Theranos’ allegations “preposterous” and “pure fantasy.”

In recent months, Theranos, once a darling of the media and investors, has faced its own scrutiny and sanctions from federal regulators.

Chen handles intellectual property licensing and transactions, while Fuisz is a litigator. He has represented Hitachi, while she worked in-house for the company earlier in her career, Vinson & Elkins said.

“John and Jennifer are outstanding lawyers and their addition reinforces our commitment to building and maintaining a world-class intellectual property practice,” said Vinson & Elkins chairman Mark Kelly in a statement.

Vinson & Elkins has been beefing up its IP offerings this year. The firm opened a Taipei, Taiwan, office focused on matters in that field, and a Texas-based group of five partners joined Vinson & Elkins in June from Wilson Sonsini Goodrich & Rosati and Akin Gump Strauss Hauer & Feld.

Chen and Fuisz were not available for an interview Monday.

Correction: The law firm McDermott, Will & Emery at one time represented Theranos, though former partner John Fuisz did not. A previous version of this story misreported the attorney-client relationship. We regret the error.

Contact Katelyn Polantz at On Twitter: @kpolantz