The Pennsylvania Supreme Court has rejected the appeal of a Superior Court ruling that tossed out a $625 million legal malpractice lawsuit against Duane Morris.

The suit alleged Duane Morris negligently failed to file an appellate brief in a federal case but a three-judge appeals panel in March unanimously affirmed a decision by the Philadelphia Court of Common Pleas granting the law firm’s preliminary objections. The panel held the suit could not proceed because the plaintiffs lacked standing in the underlying suit.