Vertex ends work on one hepatitis C drug, continues another Tue Sep 25, 2012 9:50am EDT (Reuters) - Vertex Pharmaceuticals Inc said on Tuesday it will discontinue development of an experimental drug to treat hepatitis C after it failed to show sufficient efficacy to warrant further study. The company, which was developing the drug, known as ALS-2158, with partner Alios BioPharma Inc, said it will continue development of another hepatitis C drug, ALS-2200, after it showed promise in an early trial. The company said it is planning one mid-stage, or Phase II, trial of ALS-2200 in combination with the drug ribavirin and one trial to evaluate ALS-2200 in combination with the company's existing drug Incivek. Vertex acquired worldwide rights to ALS-2200 through a licensing agreement it signed with Alios in June 2011. The drug is designed to inhibit the replication of the hepatitis C virus and the virus does not appear to become easily resistant to it, the company said. Reporting By Toni Clarke; Editing by Gerald E. McCormick