Kelley Drye & Warren was knocked out of defending a longtime client Monday against a lawsuit by a company the firm represented when it was sold in 2008.

U.S. District Judge William Martini in Newark upheld a decision by a magistrate judge disqualifying Kelley Drye because confidential information it obtained in handling the sale was central to the client’s defense in the current litigation, H20 Plus v. Arch Personal Care Products , 10-cv-3089.