A law firm accused of malpractice for allegedly turning down a $25 million settlement offer has lost its bid to take the deposition of the chief mediator for the 3rd U.S. Circuit Court of Appeals who, the firm claims, would testify that no such offer was ever made.

The malpractice suit stems from McKissock & Hoffman’s representation of the plaintiff in Polymer Dynamics Inc. v. Bayer Corp. , a case that resulted in a $12.5 million verdict in June 2005.