Health insurer Anthem Inc on Thursday said it reached a deal under which Gilead Sciences Inc's hepatitis C drug Harvoni will be the primary treatment for patients infected with the most common strain of the liver-destroying virus.

Anthem said the deal effectively lowers its hepatitis C treatment costs. "We were able to achieve a very competitive rate and a freeze on retail pricing for 2015," the insurer said in an emailed statement. "That does favorably impact plan costs for 2015."

Gilead has come under fire for the high cost of Harvoni, as well as predecessor drug Sovaldi, which was launched in late 2013 at a price of $1,000 per pill. Harvoni has a list price of $94,500 for 12 weeks of treatment, or $1,125 per daily pill.