The approval of AbbVie’s Mavyret is bad news for competitors like biotech giant Gilead, whose hep C treatments are an integral part of its product portfolio. Gilead stock dropped 2% in Thursday trading while AbbVie shares gained modestly.

Gilead actually has its own “pan-genotype” hepatitis C medicine, Epclusa, which was approved last summer. That’s in addition to the drug maker’s blockbuster medications Sovaldi and Harvoni, which elicited major controversy over their steep prices despite their milestone statuses as the first true HCV cures to hit the market. (Sovaldi is one part of the drug combination that comprises Epclusa.)

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But a growing field of competitors ranging from AbbVie (ABBV) to Merck (MRK) have put the squeeze on Gilead’s (GILD) dominance in the hepatitis C space.

Some of these companies have managed to undercut Gilead on price; others, like AbbVie with its new approval, have come through with an advantage on dosing. Epclusa requires 12 weeks of treatment compared to Mavyret’s eight. The latter therapy can also provide a new option for patients struggling with the most prevalent hep C form in America, according to the FDA.

“This approval provides a shorter treatment duration for many patients, and also a treatment option for certain patients with genotype 1 infection, the most common HCV genotype in the United States, who were not successfully treated with other direct-acting antiviral treatments in the past,” the FDA’s Dr. Edward Cox in a statement Thursday.

Gilead claimed an unexpected victory in its most recent earnings report from a bump in its hepatitis C franchise. But, at the time, analysts warned that continued competition in both hepatitis C and HIV treatments—the two major Gilead mainstays—would continue to dog the firm going forward.