For the last several years, patent attorney Zachary Silbersher has been a stone in the shoe of Allergan and now the company that acquired the Irish drugmaker, AbbVie.

But on Thursday, AbbVie got a win over Silbersher in an unusual whistleblower case. In federal circuit appeals court, a three-judge panel ruled unanimously against the legitimacy of his claim that Allergan and Adamas Pharmaceuticals used fraudulent patents to extend their monopoly on two Alzheimer’s drugs, which allowed them to overcharge the government.

Biogen successfully fended off a patent challenge from generic company Mylan over its multiple sclerosis (MS) drug Tecfidera. Mylan had filed an inter partes review hoping to overturn the last of Biogen’s Tecfidera patent, but the U.S. Patent Trial and Appeal Board ruled in Biogen’s favor. The patent won’t expire until 2028. The drug brought in $4.43 billion in 2019.