An experimental drug for one of the most difficult-to-treat types of hepatitis C has been approved by the Food and Drug Administration, adding to the surge of new options for patients with the liver-destroying virus. Daklinza , developed by New York-based Bristol-Myers Squibb Co., is the first drug approved to treat genotype 3 hepatitis C. It's to be used with Sovaldi, one of two blockbuster hepatitis C drugs sold by Gilead Sciences, along with Harvoni.