For the first time, the US Food and Drug Administration (FDA) revoked a breakthrough designation for two drugs on their way to approval. The agency told New York–based Bristol-Myers Squibb (BMS) in January that two of its combination regimens for treating hepatitis C virus (HCV) had forfeited their breakthrough status due to the “evolving HCV treatment landscape.” Since October, FDA has approved antiviral combinations Harvoni (ledipasvir-sofosbuvir) from Gilead Sciences and Viekira Pak from AbbVie to treat HCV, prompting the regulator's decision to revise its 'breakthrough' designations for other drugs in that indication. Both BMS combos contain daclatasvir—an HCV NS5A protein inhibitor. One combines daclatasvir and asunaprevir (an NS3 protease inhibitor), the other, daclatasvir, asunaprevir and BMS-791325 (non-nucleoside HCV NS5B polymerase inhibitor). Submissions of a new drug application for daclatasvir in combination with other agents will not be affected. The agency also told Merck in January that it intended to rescind the breakthrough designation for its investigational combination grazoprevir-elbasvir to treat HCV.