In a bid to maintain its dominance in the HIV market, Gilead Sciences (GILD) allegedly conspired with other drug makers whose medicines were part of a so-called combination cocktail in order to block generic competition, according to a lawsuit filed by AIDS activists and two unions.

The complaint describes an unusual scheme concerning these cocktails, which are actually fixed-dose combinations of different medicines and have been widely used for several years to combat the virus. Although Gilead has been a dominant player in the HIV marketplace, other companies manufacture HIV medicines that are useful components in a cocktail treatment.