Cephalon can’t rely on the strength of its patent for a narcolepsy drug in a reverse-payment antitrust suit brought by the Federal Trade Commission because the judge found in a related case that the patent is invalid.

Cephalon, which was recently acquired by Teva Pharmaceuticals, had claimed to have invented the formula for its wakefulness drug called Provigil when it applied for patents in the 1990s. However, in a related case brought by competing pharmaceutical companies, U.S. District Judge Mitchell S. Goldberg of the Eastern District of Pennsylvania had found in 2011 that the company committed fraud on the patent office by concealing the fact that a French company, Laboratoire L. Lafon, had actually developed the drug.