Hepatitis C drugs On 25 October, a US non-profit organization filed challenges against six core patents for sofosbuvir, a key component of three hepatitis C drugs. The medicines — Sovaldi, Harvoni and Epclusa — belong to Gilead Sciences in Foster City, California. The Initiative for Medicines, Access and Knowledge (I-MAK) in New York City argues that Gilead’s patents are unmerited because the drug is not different enough to warrant a US patent, saying that the company developed the compound by tweaking existing HIV and cancer drugs. The patents prevent cheaper, generic drugs from entering the US market. Using a similar argument, I-MAK had a sofosbuvir patent removed in China in 2015.