In 2013, Merck filed a lawsuit against Gilead Sciences, claiming that Gilead's hepatitis C drug, Sovaldi (sofosbuvir), infringed on Merck's patents.
In 2016, a jury initially awarded Merck $2.54 billion in damages, one of the largest patent infringement verdicts in history.
However, in 2018, a federal judge overturned the verdict, citing that a former Merck scientist had lied under oath and engaged in unethical conduct during the patent process.
This reversal was a significant financial and reputational loss for Merck.