Orrick Herrington & Sutcliffe has seen two teams of litigators quit to join US rivals this week, writes the Am Law Daily, with a total of eight partners exiting the US top 25 firm.

The partners include a New York-based quartet moving to Gibson Dunn & Crutcher's local practice, while Dechert has recruited a four-partner team to launch a Los Angeles branch.

The new arrivals for Gibson Dunn are Daniel Thomasch, Richard Mark, Lauren Elliot and Joseph Evall. A statement from Gibson Dunn issued on Thursday (7 April) said that the four are "known for their work as national lead trial and appellate counsel for Wyeth (now Pfizer) in more than 350 product liability cases involving claims that childhood vaccines containing the preservative thimerosal cause autistic-spectrum disorders in some children".

"We are pleased to welcome this exceptional group of litigators to our New York office," said Gibson Dunn chair and managing partner Ken Doran (pictured). "Their experience and success litigating on behalf of major companies in the life sciences, pharmaceutical, and biotech industries complements our firm-wide strengths in the areas of class actions, mass torts, and patent litigation."

Meanwhile, the former head of Orrick's national litigation team is headlining a group of lateral partners that will open a new Los Angeles office for Dechert.

Litigator Edwin Woodsome, who stepped down as Orrick's head of litigation two years ago, leads a group that also includes partners William Oxley, Christopher Ruhland and Andrew Wong. Associates may eventually follow the group as well, Woodsome and Dechert chairman Barton Winokur said.

Woodsome, who will serve as managing partner of the Los Angeles branch, advises Fortune 100 and 500 companies in commercial litigation matters, concentrating on class action defence work.

Winokur commented: "Our strategy is to have a national practice, as opposed to one that is focused locally in a particular geographic area, and these fellas have a practice, a very good practice, that is sort of nationally and internationally-focused."

The Los Angeles office will be the fourth in California for Dechert, whose other Golden State outposts are in San Francisco, Orange County and Silicon Valley.

The Am Law Daily is a US affiliate title of Legal Week.