The industry's blue chip companies took it on the chin in December with investors cashing out their profits triggered by news that Express Scripts Holding Co., the biggest pharmacy benefit manager (PBM) in the U.S., made known its plan to take up Abbvie Inc.'s Viekira Pak to treat patients with chronic genotype 1 (GT1) infection and drop from its list Gilead Sciences Inc.'s Sovaldi (sofosbuvir), the blockbuster nucleotide analogue inhibitor of NS5B approved in late 2013 for GT1 HCV.