A Washington federal judge has dismissed Encyclopaedia Britannica Inc.'s malpractice case against Dickstein Shapiro over the firm's patent prosecution work for the company, finding that intellectual property at issue was ineligible for patenting.

U.S. District Judge Royce Lamberth, in a decision issued on Thursday, found that the encyclopedia company lost its “case-within-a-case“ under Section 101 of the Patent Act necessary to prevail on the malpractice claims.

Encyclopaedia Britannica filed a $250 million lawsuit against the Washington-based firm in 2010 for “incompetent prosecution.” It claims the firm exposed two of its patents to the possibility of being declared invalid because of the company's own prior art, or information published before the patent filing which describes the claimed invention.